KR> challenge / blitz
Willie - Mark L se epos = n56ml at hiwaay.net Waar is jy? Steve REMEMBER, GROWING OLDER IS MANDATORY. GROWING UP IS OPTIONAL.? -Original Message- From: KRnet [mailto:krnet-bounces at list.krnet.org] On Behalf Of Willie van der Walt via KRnet Sent: 29 September 2014 04:37 PM To: Flesner; KRnet Subject: Re: KR> challenge / blitz Hi Larry You wrote " Please e-mail a photo and info to http://www.n56ml.com to be added to the www.krnet.org web site. Thank you. (signature)" This take me to the web page.What is the e-mail address to be used? Regards Willie -Original Message- From: Flesner via KRnet Sent: Monday, September 29, 2014 2:52 PM To: krnet at list.krnet.org Subject: KR> challenge / blitz My challenge: In reviewing the U.S. aircraft registry alone, it appears that nearly 1000 KR2's, KRII's, KR2S's have been registered over the years with maybe only 10 percent or so still current. My challenge is for everyone on the list to buy 10 post cards, go to the registry, pick 10 names in your state / country, and send them a card asking them to post a photo / info of their KR to Mark's web address (included on the card). If you can find the address of those no longer current, include them also. If each of us get just one response we could add 500 aircraft to the site. Larry Flesner Sample message: The (FAA registry / country) list you as a current owner of a ( KR2, KR2's) aircraft. We would like your aircraft to be included in the world wide listing of KR aircraft. Please e-mail a photo and info to http://www.n56ml.com to be added to the www.krnet.org web site. Thank you. (signature) ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org please see other KRnet info at http://www.krnet.org/info.html see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org please see other KRnet info at http://www.krnet.org/info.html see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options
KR> SA - AAD
Well done boet - how many have you built already? Any progress on the KR? Will be in PE later this year - you still in the same place? Take care Steve Jacobs REMEMBER, GROWING OLDER IS MANDATORY. GROWING UP IS OPTIONAL.? -Original Message- From: KRnet [mailto:krnet-bounces at list.krnet.org] On Behalf Of Dene via KRnet Sent: 15 September 2014 10:44 AM To: 'KRnet' Subject: KR> SA - AAD Guys this is not quite KR related but I just had to share. This week end was the AAD display in South Africa. All South African designed and produced aviation products are put on display, from unmanned UAV drones to gyrocopters and the awesome rooivalk attack helicopter. Standing front and centre is the very first Whisper motor glider I built. The same one that won best composite aircraft at the annual EAA convention here in 2013. I feel like a proud father!
KR> Continental
It would be nice is someone would come up with a complete FWF package, including the carb, for a decent price. +++ I made enquiries after seeing an advert and the response was encouraging, viz.: Thank you for your e-mail. We do offer an 100 Hp engine, model TMXO-200 experimental engine that is assembled from new TCM parts. This engine is all new parts and includes items such as the mags, harness, spark plugs, starter & clutch assembly, alternator and carburetor. At the present time we are in the midst of a price change and are assessing our costs and lead times. I regret that I must get back to you when I have this important information. I hope this to be less that one week, but I will contact you regardless as soon as we determine our new costs. Regards, Michael michael_you...@teledyne.com) Engine Sales Mgr. The Sept 04 Kitplanes ran an advert from Mattituck offering similar engines based on all new parts - typically TMX O-200 $15k and TMX IO-240 for $17k. A complete new TMX IO-360 for $19.6k (TMX O-360 = $18k) I heard that Superior Air Parts are offering something even better but I have not been able to find any specific info. SteveJ
KR> Hartford photo
I should have clarified that I'd done a little Photoshop work on that photo + Nice catch (without a mitt)
KR> T-88
Is there some way to thin T-88 without losing the bonding power. +++ After much research I have concluded that the short answer is NO. There are however various considerations depending on the specific application I have emailed to you (direct) a copy of an article on this subject. This paper was in reply to a similar question pertaining to the West system, but I believe that the info pertains to epoxies in general. Steve J
KR> How far will a KR roll
I switching to Cleveland wheels and I'm awaiting my purchase ... + Hi Orma Why are you changing? Take care Steve
KR>KX170b
Does anyone have wiring diagrams for the KX170B ++ I have sent the pin-outs to you direct - hope this is what you are looking for. Take care SteveJ
KR> over the hump!
Bottom line is that I'm no longer afraid of this thing There you go now - enjoy some hard earned time aloft. I realize that it may still be a while, but I am already looking forward to the final paint job. Steve J
KR> ground effect and stall speed?
Does anybody know if ground effect lowers your stall speed? +++ I always believed that it did not, so I was surprised to read the compelling evidence from John M, viz., "Mine actually lifts off at 37 knots in ground effect and will fly a foot or so above the ground however stall at altitude is at about 42 knots". I suspect that the TAS does not change, but the IAS does due to the ground effect on airflow around the pitot. Would be interesting to hear from the KR that has the pitot on top of the Fin. For your purposes right now, I guess the best answer is yes - what you will see on the ASI will be lower in ground effect (compared to readings observed at altitude). What have you decided regarding the canopy latch and the turtle deck attachments? Good luck Steve J
KR> the importance of an airspeed indicator.
Notice that you never got "airspeed" until you had your first solo. You were taught to recognize attitude for takeoff , level flight and landings. They trained a lot of good pilots by this method. Jeez guys - Africa wants some Friday lea-way here. There was a time that they amputated legs without any anesthetic. They trained many good doctors then and also saved many lives - but that was then. Now we have flush toilets, ASI's and VSI's etc. Have a great weekend. Steve J PS I was surprised at the amount of visible flaps on 56ML (one of the recent photo's) - I presume that you are happy with the aileron authority Mark - thus a good balance on that short outer section.
KR> vortex generators
ok has anyone done it , they sound good sounds a lot safer to me with them ,i will even sacrifice some spped to get the stall down and quicker t/o >From my experiments (PA32) you don't need to sacrifice anything. VG's can help achieve different things, do enough reading and decide what your requirement is. I get mine from: http://www.mywebco.com/cci/ Good product and the lowest price. Take care Steve J
KR> N56ML flies!
Congratulations Bwana = Wise move to put her in the best hands available. = Why did you opt to seal the fuselage / Tdeck gap? Good luck with the next flight. Steve J
KR> krnet
sometimes things get off subject,some times subjects are flogged to death, but for the most part this is great to be able to communicate with so many people that are interested in what I'm keenly interested in. My accolades go to Mark L. and crew, I personally think you've got something real good going here +++ Agreed an seconded I did actually learn from the tool discussion - certainly much more than I learnt from endless yee haa's and months of countdowns. But then again, they were KR yee haa's and KR meet count-down Steve J
KR> GRS Ballistic Chute from Oz
Hi Barry K Where do the cute cables attach to on your airplane? (what would the attitude be whilst suspended by the chute). The first engine mount looked pretty robust, why did you change it to a tubular construction? Take care Steve J
KR> GRS Ballistic Chute from Oz
I would be hanging tail down when descending. While this sounds bad, it is not, the tail of the aircraft is a crumple zone and my back and head are fully supported. Thank you - that makes complete sense and certainly simplifies everything - perfect KIS. Steve J
KR> Flight Report
Normally I go full power and the tail is off the ground, 2 up I have about 20 meters ground roll before the tail comes up Barry - do you let it come up by itself, or do you deliberately bring it up with down elevator? Full down? Performance from the Jab sound pretty good considering you have fixed pitch. Take care Steve J Zambia
KR> ELT where to buy cheap
does anybody know who sells an inexpensive ELT? other than Aircraft Spruce, Wicks? +++ RST Engineering - http://www.rst-engr.com/ Loads of good stuff for home builders Steve J
KR> Ribs, Foam and Plywood - replacement parts for Serge
By the way, they were not made by Dan Diehl. They were made in South Africa, where one guy used to have a KR2 license from Ken Rand, and was manufacturing and marketing the pre-molded parts locally. +++ If you ever need new parts - you can get exact replacements (from the same moulds) - I gather from Jaco Swanepoel [jacosw...@yahoo.com] that Peter Eich still has the moulds and offers: (Prices may have changes slightly) Wing skins - ZAR (US$ 1,250) Stub wing - ZAR 2,000 ($335) Cowling - ZAR 1,200 ($200) Spinner - ZAR 800 ($135) Very nice canopies (stretched / widened) are available ex CT - ZAR 1500 ($250). This included fitting to the pre-made canopy frame. Can also be tinted. Did you have any hassles converting a ZS PPL to Europe - I gather that the Euro / UK (JAR) requirements are stiff? Take care Steve J
KR> Is it really a RAF 48
The trouble is, what I get is different from the KR2 Scale 1 drawing. The KR2 profile is slightly thicker. What the hell is wrong here? Hey mon ami There is not much wrong - your airplane flies great - no? The RAF 48 (according to my software) is 14.96% at 30%Ch or 182.43mm for the 1912.2mm (48") section. When I measure this dimension in Auto Cad it comes out at 182.43mm - 0.09 diff, so it should be correct? Max camber of 2,93% falls at 40% Ch. Steve J
KR> Time ran out!
Dreams do come true, and N 61305 will fly again, and Larry now fly's with Eagles. ++ What a wonderful thing to say. This is one of those rare emails that I cannot bring myself to delete - just read it again and again. Sure started my day with something extra - Thank you
KR> ZS-UKU
Dankie Leon You provided a trip down memory lane for me as well. I met Sakkie (late 70's) when he was at the boat stage with UKU - at the time he and his dad owned the DIY centre in Krugersdorp. Peter Eich was the KR SA guy and Sakkie did most of the foam shaping work in Peter's hangar at Bara G airport (Uncle Charlie's South of Johannesburg). I recall some interesting discussion at EAA meetings, Murray Cohoe was the inspector for UKU and those wing tips provoked interesting debate. They were initially decorative, but the plans were to develop them as tip tanks (that did not impinge on the G limits). The epoxy / ester fuel tank debate raged in SA 25 years ago - SASOL was already supplying petrol laced (heavily) with methanol (alcohol) distilled from coal. It screwed up seals and gaskets and the clever guys were warning about the potential impact on GRP's The last time I saw Sakkie (early 80's) he let me fly UKU - he had just completed a dirt strip on his 10 acre plot (homestead). This took some doing as you say, it was right next to FALA. By then he was the KRSA guy and working hard on improving VW conversions with great emphasis on dual ignition. UKU was initially white with the (then BMW) flash colours of red, green, something. After a bad landing en route to Margate (that punched the flex bar suspension through the top of the wing (original RR fold-back retracts) - he changed the colours to the very attractive markings that you describe - biscuit with trim in tan, caramel and brown. I recall the engine (initially ?) as being a 1700cc VW with a RayJay tubo and Posa carb. For some reason it was called an "injection" carb. Ftrom what I have since read on KR net - I can understand why he called it an expensive fishing sinker ZS-UKU sounded cool, it looked cool, and it was cool. I gather from Jaco Swanepoel (FAWB) that peter Eich is back in the KR business in Gauteng, offering pre-molded cowls and wing skins. Acrylform (CT) will come up with a first class canopy for under R2k ($275). At 42 you are at the perfect age to get started on your own KR2S vet ses. Beste Steve J Zambia
KR> Pre Flight 'n props
= I set the pitch at 19° which is equal to 54" pitch. = static rpms yielded the same as my 2-blade Sterba 56x64 prop + Turning 10" less pitch at the same RPM is a bit like a car in a lower gear, i.e. a ratio that provides less fwd speed for the same rpm. I would expect the static thrust to be higher. In addition, I believe that three blades are better than two in the thrust dept. (not cruise) so that will further contribute to the results you observed. Like any other "wing" at an AoA over 16 degrees - a propeller blade at typical cruise or take-off rpm and zero fwd movement (static) is stalled to some degree, over varying parts of the blade surface. The more pitch, the greater the degree and the more of the blade lifting surface will be stalled, producing higher drag, thus lugging the engine RPM down and producing less (static) thrust. The same propeller will unload as the "apparent" angle of attack reduces due to fwd movement, thus improving in efficiency as the aircraft accelerates - hopefully peaking (in efficiency) closer to the desired operating speed. An under-pitched propeller will show promising static thrust levels because the set-up is more efficient (less inefficient). This propeller will probably reach max efficiency sooner in the take off roll and may be substantially less efficient at the desired speeds of climb and cruise. Just like a car would be in the cruise at anything less than top gear (higher ratio). As we know, the trick fixed with pitch propellers will always be to find the best compromise for the plane / engine combo and even that will change with weight, temps and general requirements on the day - but I somehow doubt that a propellers' efficiency under static conditions could be a reliable indicator of a good compromise - these are not conditions the airplane will ever encounter in normal flight - maybe just as it stalls, but that is hardly normal flight. I would hang back with re-pitching the plank until you have established what the plastic will do in the cruise. The plane looks really good and I am pleased that the spinner saga turned out Ok. Good luck Steve J Zambia
KR> Fuel Injection
RFI has come up with a "cut and paste" EFI system for aviation ++ This closes the gap for me - the only remaining issue between an IO something and a Corvair. After nearly 30 years in this game, it just must be injected. I have searched on RFI without joy - any more info much appreciated - thank you. Steve J Zambia
KR> Tweety update
Thank you Orma, well described, I had no problem fully understanding your arrangement and it certainly appears to be a good solution - it works. I was not aware of the existence of a dual (piggy back) pump - sure is the ideal solution in this case. Is scavenging a turbo a new concept (first I heard of it) or are there many existing cases? My understanding has always been that having the oil under pressure (at the turbo bearings) is what created the "bearings" that the turbo shaft ran on. I would have thought that placing these chambers under vacuum (scavenging) would reduce the effective pressure at the bearing surface. That would reduce the pressure on the seals (maybe even produce negative pressure) and thus prevent any oil getting past the hot section seals into the exhaust, thus achieving what you set out to do. Question is, will the reduced pressure affect the turbo life? What is the consequence of a failed turbo in flight (in this type of installation). Could you lean out the mixture and still have say 70% Power? Do you know if a similar approach could be taken on the Corvair engine? Enjoy the Easter break Ron -Original Message- From: krnet-boun...@mylist.net [mailto:krnet-boun...@mylist.net] On Behalf Of Orma Sent: 25 March 2005 07:32 AM To: KRnet Subject: Re: KR> Tweety update Hello Ron First of all, type2 and type 4 parts are mostly interchangeable. The Vanagon automatic, utilizes a piggy back dual oil pump to provide pressure to the transmission. It is this pump that I am using for the turbo scavenge pump. The suction side of the pump is connected to the turbo oil return, and the pressure side of the pump is connected to the side of the engine case at the oil sump. Please see http://kr-2.aviation-mechanics.com/Turbo%20Oil%20Leak.htm The pump sucks hot frothy turbo return oil and passes it under pressure back into the engine case. The turbo oil supply is taken from the top of the original oil cooler boss and is routed directly to the top of the turbo. The Ford engine that this turbo is applicable for has a requirement for 50 psi. That being said, the turbo is getting what ford required. The pump is two pumps driven by a common shaft that is turned by a slot in the cam gear. Both pumps are completely separate, each with it's own inlet and outlets. Was it worth it? Even though the dust has not settled yet, I can tell that I have a lo more power. The difference is like night and day. My pervious top speed was 129 kts. I have exceeded that in the pattern at PTK, seeing 135 kts. My climb was always around 500 fpm ( my KR was over 615 lbs). On a calm day I can now do over 1000 fpm. Your short answer is YES. It brings back that YeH feeling. It takes the Hum out of Hum Drum and leaves the Drum with a quickened beat. Orma ___ Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net please see other KRnet info at http://www.krnet.org/info.html
KR> Folding Wing Brackets
The partly built Aussie design PT-3 has the same WAF as the KR Hey Phil I have some info on the TP3 designed by Thomas Philippa in 2001, but lost contact with Murray Gill (Oz) who was my connection. I heard later that he went back to school to study philosophy or something. Do you have contact with this or any other builders? Take care Steve J Zambia
KR> FIRST FLIGHT
Well done Mark - here's to many happy hours. Steve J Zambia
KR> LEDs
These may be old news, but just in case: http://www.ledtronics.com/ http://www.creativair.com/ http://www.killacycle.com/Lights.htm http://www.steinair.com/
KR> Header Tanks
My wing tanks are from the back of the main outter spar aft 13 inches and 45 inches outwards. these hold 45 litures.( 11 US Gals) +++ Hey Phil Our gallon is like your Oz gallon, i.e. an Imperial gallon of 4.55 L. The only thing American that is not bigger than every one else's, is their gallon - one US gallon is only 3.785 L. (or 11 US gal = 41.64 L). Only reason for pointing this out is it caused me some panic as a fresh PPL in 1976 when I used a fuel burn in L/hour and worked out the range (Grumman AA5) assuming Imperial gallons. I launched from your home town headed for Springbok in the NW Cape - 4 hour cross country with what emerged later as a 4.2 hour range. Steve J
KR> Kr Costs...
Stephen, what model Garmen was that? ++ Hi Dene - Sorry, I can't recall. It was very much like the typical Garmin hand-held before the moving map units came along. The model number was one digit different from the otherwise identical aviation GPS - something like x93 instead of x94. I did try to find some email correspondence to refresh my memory, but I probably dumped it when I gave the GPS away - I did however find the Garmin plug pin-outs (from the same guy at Garmin) if anyone needs this. Steve J
KR> Header Tanks
My wing tanks are from the back of the main outter spar aft 13 inches and 45 inches outwards. these hold 45 litures.( 11 US Gals) +++ Hey Phil Our gallon is like your Oz gallon, i.e. an Imperial gallon of 4.55 L. The only thing American that is not bigger than every one else's, is their gallon - one US gallon is only 3.785 L. (or 11 US gal = 41.64 L). Only reason for pointing this out is it caused me some panic as a fresh PPL in 1976 when I used a fuel burn in L/hour and worked out the range (Grumman AA5) assuming Imperial gallons. I launched from your home town headed for Springbok in the NW Cape - 4 hour cross country with what emerged later as a 4.2 hour range. Steve J
KR> Fit two people
The KR2 and KR2s are the same in this dept - 34" wide. This should not be an issue as most every KR built deviates in terms of cockpit width. Widening the cabin by as little as 4" makes a big difference. SteveJ +++ What is your name - Ronald or Steve?
KR> Fit two people
Brian - I would not like to travel long distances in something with dimensions like a Cessna 150 at about 36". Ken - I have yet to notice anyone "highly suspicious" on this group about anything. +++ I have seen Ron post a few times and 3 or 4 Steve's but never seen another Steve J - did not now there was another?? The question is a very valid one, I spent a great deal of time reading various builder reports on exactly this topic. On my plans the fuse is 38.12" at the widest, unfortunately this forward of the shoulders. At the shoulders it is about 37" at the top rail of the boat. That is the outside dimension, so deduct 1.25" (2 x 5/8") for the top longeron and doublers, thus an inside dimension of 36.75 - 1.25 = 35.5 (at the rear spar / shoulders). After reading a great deal of comment from netters, I concluded that I could safely get away with anything up to 44" outside, plus move the wide point back to the shoulder position. That is 5" more than the older C172. As someone else commented, you can customize the seats to suite your shape, age, posture etc. and end up with a very comfortable airplane. You could even modify the seats over time until you find exactly what you like. I am sure that the popularity of the KR stems from the fundamental simplicity of design and materials - it really is easy to customize. It may not always be safe or even wise to do this, but it is easy. Many builders stretch the boat - I think I have read about another 14" onto a 2S. Apart from the other benefits, this helps to accommodate the extra width in softer curves. At least Mark L and Don Reid discuss this (and other mods) on their respective web sites. Steve J Zambia
KR> Wood
It's been a while but I'd say that's for building the ailerons. + Thanks Bwana - I should have spotted that one. There has been talk of laminated spar caps recently and this looked like the right size for that - had me wondering. Steve J
KR> Kr Costs...
Oh yeh, forgot to mention Worldmap is a marine unit and as anyone knows when the word aircraft is mentioned the price goes up 10 times. I have a Lowrance now and it works a treat. My first attempt was also a cost-saver, but it turned out to be a bad idea - check out the non-aviation GPS carefully. I bought a non-aviation Garmin for a great price. I was very happy with my new toy - it worked fine in the car but it would not work in the airplane. After much frustration I learnt that it would not function over certain speeds - not sure now, but I think it stopped registering after 70mph. Take care Steve J
KR> Back on the subject of wood
I recalled reading a government report from the twenties pertaining to use if alternative wood in aircraft production. I've located the link and thought I'd post it +++ Thank you Bill - I am fascinated by this topic and cannot wait to read the article. The link did not work just now, I will try again later. Steve J
KR> Seat position
Good day netters I am trying to establish how much space there actually is between the pilot and the control stick. The relevance of this is that some folks have shorter legs than others and need to sit closer to the rudder pedals - other folks have bigger paunches and need to sit a bit further back to fit the beer belly in. Some adjustment in the rudder pedals helps, but I need to figure out how much the seat can be moved forward without creating a problem. I am looking at ways to move the seats closer to the CG so as to reduce the CG shift from one to two occupants. The original design (and every KR I have seen) has the single and dual stick arrangement mounted on the aft surface of the main spar. I would prefer to do the same - this avoids making any extra holes through the main spar. I guess the real question is, how comfortable are different size folks with the present (standard) configuration? Could (should) the stick be further / nearer to the pilot? Thanks Steve J
KR> Seat position
There is not a whole lot of room to work with anyway. The more forward you can sit, the better Thanks Dan The above comment is the core of my question - get as far fwd as possible, BUT how much room is there to do so and still feel comfortable with the stick position, especially for someone with a bit of middle age spread. The only KR I ever flew had a centre stick so no way to tell if there was space to move fwd or not. I don't see how mounting the stick on the aft side of the main spar avoids extra holes in the main spar. The small bolt holes are not the concern - mounting the pole on the fwd side (to get another 4 -5 inches in front of the pilot) will require a dirty great hole through the spar for the push rod. I flew a KR for 185 hours that had a center stick and that is one of the most aggravating things there was about the KR. ++ I am pleased you made that point - I have always wondered if there was that much difference - now I know. Take care Steve J
KR> Seat position, rudder pedals
Mark L says: I wouldn't mind if my stick was aft about 3" more than it is. See http://home.hiwaay.net/~langford/kcontrol.html ). Thank you Mark L Colin R says: My seats are 4 inches further forward then plans, bottom 4 inches forward of rear spar, and seat back 5 inches. My dual sticks (thanks Brian Kraut ) are very comfortably right at my knee. - Thank you Colin R + This is exactly what I was trying to establish - thank you both. I still have the option to move everything - Firewall, seats and rudder pedals a bit closer (further forward), even the canopy if need be. I needed to know the true position in a completed airplane. My root chord is larger so the distance between spars is 3" greater, so I already have that in hand. From your info I now know that I can move the seats (payload) a good 6" fwd and still plan on having the controls mounted on the back of the main spar. My primary motive is to minimize the aft CG shift (when the second trusting soul comes aboard) by relocating the seats closer to the CG. Ideally the variable payload should be on the CG, but that is the price of side-by-side seating. I do appreciate the impact and consequences of this change, but the effort is worth having an airplane that has a relatively small CG migration between driver only and full house. Is that not why we choose the KR - it tolerates our whims. I am dead keen to hear the responses to the point raised by Barry K - what is the skinny on the single stick vs dual stick? I somehow figured that a "side stick" would be more convenient, it is aligned with the push-rod (arm), it caters for an arm rest (to reduce PIO) and makes for uncluttered space in front of everyone. I must be wrong, almost everyone is opting for dual controls - even guys that had already completed and installed single sticks Steve J
KR> update
Several times I ran out of control input and just had to ride where ever the plane was going in the turbulence. ++ Wow Colin, can you say a bit more on this please - which control(s)? Are your control surfaces standard? Steve J
KR> Wood
The Aircraft Spruce catalogue (web page) calls for 24' of 1/4" x 3NOM spruce - what is this for? Take care Steve J
KR> Joey 2 - I will call mine Cobber
>From what I understand, Gary has stretched the KR2S some what and modified/improved the design. He has also made many pre-formed parts and had the redesigned aircraft and pre-formed parts approved as a kit in Australia. This, I feel, is a great step forward in the evolution of our wonderful ++ I totally agree - what has he done wrong? There are other people that offer KR bits - landing gears, canopies, wing skins, metal parts etc. He just figured to first improve the design - then make parts, kits etc. There is a greater difference between the Joey and a KR2S built to plan then there was between the first KR and the airplane it was copied from - as we know, the KR series has its roots (very close copy) of one of the original "home built" airplanes - open cockpit, RAF 48 and all. RR added the folding legs. With great respect to the original KR designer(s) - the design was never really a useable two seat airplane of any great note. It worked in the sense that you could cram in two small souls and go fast with a VW for not much money. Most of them are flying well over there design weight and power. Many have been intelligently modified to cope with the new role, many may not have been. The KR was a great lesson in a new building technique using readily available "space age" materials 30 years ago. It was cheap and easy (quick) to build and thus received attention. There are many, many airplanes out there that cashed in on this technique. It is the innovation and skill of the individual builder that evolved the KR to something very special. Have a close look at the RV's, Lancairs, Falco's, GP4's etc. - not much deviation in the basic airplane, they are generally built to plan. I have not seen too many folks make a retract RV or a fixed leg Falco. You have to ask why. Yes - it was inevitable that someone would hang a turbine on an RV (or a KR) - but that aside. Not many KR's are the same - each one has something longer, bigger, wider, taller, stronger etc. You have to ask why. Built and powered to plan, a KR2S (in my opinion) is a nice airplane for those that it suits. Garry Morgan changed all the things that did not suite him and came up with exactly what most KR builders want (and do anyway), but the changes were properly re-engineered to handle the revised requirements (loads/ duty /speeds). He has produced a better mousetrap - and had it approved as such. It is available in a variety of kits /sub kits and he has done the engineering around different engine installations. Not unlike most KR2SX's around - it is a very different airplane to what comes off the plans. I cannot see how anyone can take umbrage to that. Some could even argue that you should really to call it something else if you deviate from the plans to that extent. If one of the radically different KR's (and there are many) crashed and upset the insurance on all the other's - bet you there will be plenty of chirping about NOT calling it a KR. Steve J Africa
KR> Fuel Pump Tests
So I conducted some tests. ++ Well set up exercise with positive and tangible results - thanks Dan. Steve J
KR> Fuel Pump Tests
Mark I hope you have an engine driven pump as well!! If not what happens when you've run one tank dry, I like Mark's approach. My installation will add one more pump rigged to transfer fuel either way. Then all the fuel is available even if one primary delivery pump and the mechanical pump both fail. Steve J
KR> Even less KR related
and shut down the left engine on the Beech Baron we were in trying to be a smart *** since the hydraulics were on that side .. . this dummy never read the maintenance report prior to take off where it clearly stated that this bird had a bad problem and wouldn't restart left engine. No Baron has any hydraulics - they all have electric flaps and u/c, must have been a DC3. How about the other dummy - did he read the maintenance report - why launch in an airplane that is not airworthy?
KR> CCW wood screws
Some time ago someone gave me a box of stuff that had belonged to someone that was no longer around. I understand that the old timer spent his time restoring old British airplanes - mainly wood (Tiger Moth and Chipmunk?). I was the only airplane guy they knew, so rather than toss it out, it came my way. There were some useful things in there, including a super tubing cutter for the smaller sizes (under 1/2") and turning tools for ferrels, flaring tools etc. Recently I needed some wood screws that were going to be covered with ply forever. I did not know if the moisture in the spruce (6%?) would ultimately corrode steel screws, so I decided to use brass just in case, but where to on a Sunday eve. I remembered seeing some brass wood screws in one of the little drawers in this box of treasures - they were the perfect size. Problem is, they would not do what screws are supposed to do. After a period of total perplexion, I finally realized that they had a left-hand "thread". I turned them backwards and in they went. I was reluctant to bury them under the ply, they may be unique and valuable. I cannot dredge up any logical reason why anyone would make a reverse thread wood screw - maybe to counter harmonic vibrations?? I doubt anyone else has any answers, but worth mentioning. Take care Steve J
KR> aircraft have been flown to the published limits
I've seen him fly well over 1300 pounds (and heard of 1400 lbs), AND register 6g's on his g-meter, all in the same flight. + Do we know if he built a stock spar? RAF 48 I presume? Steve J
KR> Bathroom Scales
That is much more accurate than just adjusting the scales to read zero then expecting them to be accurate at 250 pounds. Water is a relatively accurate "known" weight for calibration purposes. Steve J
KR> To laminate or not ...
Don't forget, most laminates (such as plywood) are stronger as compared to a solid peice of wood the same thickness because of the different grain orientations. +++ I also believe this - so here is a question for the knowledgeable among us: How about making up wing spar caps out of several laminations of ply? As we are taught, a good scarf makes for any length you like without any strength compromise. 8 x 1/4" laminations would make up the correct depth (for a 2" spar cap) and work just fine for the bent spar. Using 5 ply must surely result in a bullet proof spar? Steve J
KR> VE resin
Just to clear up my mind Are you saying that if you paint PVA release agent onto a layup on V/E or P/E resin it will make it dry better?? V/E does have drying problems, it stays tacky for some time, Does PVA help this. PE and VE resins exude a gum to the surface (surfaces?) when curing - this is the perceived tackiness (that takes ages to dry out). I once used a high quality PE that had reportedly been "de-gummed" and it was very nice to work with and sand, like fast curing epoxy. A US manufacturer for model airplane products (K) also offers something similar that I have used. The big difference is in how the cured resin will sand, the gum quickly clogs up the paper and that is a real pain. I am also interested in the comment regarding PVA as a potential solution, but what are we talking about - PVA wood glue? PVA water soluble release agent? PVA wall paint? Steve J
KR> Widening KR-2s Fuselage - long
The more I read about the KR-2S the more it grows on me. However, I have also read that, like the VP-2, it makes a better fat single seater than a cruiser for 2 adults. + Hi Sean I have been through the very same thought process and frustrations for a year now - including spending loads of time designing my own based loosely on a KR. Maybe my thoughts and observations will save you some time, so for what it is worth. I prefer to work with wood and I do not have the budget to throw $25k at a kit that is headed for $50k plus. There is little doubt that RR offers the basis for a great airplane with a low budget and costs that can comfortably be spread out over the build period - particularly if you live in the US where you have immediate (overnight) access to everything at really good prices. Construction can start with a small budget - just enough spruce, ply and adhesive for the fuselage, so $500 will keep you busy for months (the entire spruce / ply / foam package is only $1500). There is also little doubt that it can be built as a competent and safe airplane that will last just as well as any glass slipper or spam can - Dan Diehl's KR2 (N4DD) will be 30 years old this July and still going strong (and looking good) - there are many others. Consider the improvement in technology over 30 years, the ease of communication and the advent of refined engine conversions - it becomes clear that it has become easier to build a stunning, reliable and safe airplane. The important part of your question is really about changes to the original design. The short answer is to keep these to a minimum and the build will be much faster (there are KR's that have been completed in a few months) but in order to have a realistic two seat bird - some changes are necessary. There is enough data from completed airplanes to know that this in entirely possible provided you understand that each change has the potential to enforce other changes etc. and will substantially increase the build time (and weight). The KRnet is a super source of info, along with many well documented builder web sites. It is like having 10 different step-by-step construction manuals. I have researched all the airplanes where info is available - this is my advice. Refer Mark Langford's site (Miscellaneous Stuff) for the fuselage stretch (not what he did but what he says he wished he had done). Redraw the side and plan view incorporating the new length and moving the wide-point (plan view) back closer to the wing trailing (better aerodynamics and cockpit width were it is required). Any stretch over the stock KR2S will soften the effect of widening the fuselage - some have added up to 10" (34+10=44"). As a guide, the older C172 is 39" at the shoulder (inside width), so anything over that will be nice. The 2S already ads an inch or two to the fwd fuselage and that should make for ample leg room. If you are going to use a larger (heavier) motor - don't add any more length to the front. One other mod that may be helpful for tall people (refer Larry Flesner) is to lift the turtle deck / canopy an inch or three if necessary. No more than necessary, this directly affects frontal area. Resist the temptation to "beef things up" - rather do a really good job of building to plan with good materials. It is unlikely that you will build out at anything like the weight suggested by RR, so here are my thoughts on accommodating a higher MOTW. I know that MANY KR's are happily flying around at 200 and 300 lbs over weight - the KR that I flew weighed in at 1200lbs with myself and the builder on board. I believe that the wing loading at 1200 lbs is still perfectly acceptable, particularly if you have enhanced the stability (CG envelope) by stretching the aft fuselage (increased tail moment / tail volume). I don't believe that it is clever to totally ignore the fact that the spar was designed for less - even if it appears to work for others. If nothing else, they have a reduced safety margin for the day the bird encounters abnormal loads from severe turbulence or whatever - sh*t happens. We know that the AS 5048/15 results in a deeper spar, so we know that the spar is meaningfully stronger if made exactly according to plan (except for the extra depth) - so that takes care of that. I have read that the WAF,s are more than adequate, but to my mind these are so critical to the integrity of the wing and difficult to control (quality of the metal / treatment) so I did some extra reading. Search the KR archives on "WAF" and look for input by Don Reid. He discusses the topic and makes some suggestions for improving the existing arrangement - he provides the rationale and arithmetic that convinced me. Also visit his web site and look at "some older pictures" - his rendition of the main spar WAF's are visible in the pictures (single row of larger bolts). I would discuss (with a structural engineer) the impact of using the next size up 4130
KR> AS 504X CofG
... for a low-wing monoplane such as the KR, a starting point would be to use 18% and 34% of MAC. For a wing with a 48" MAC, that is roughly 8-1/2" to 16-1/2" aft of leading edge . +++ When someone starts asking questions about CG location, he or she may be pretty close to launching - so it is important that they get the right info in the correct context. The info provided by OZ is good and would be accurate and relevant for a constant chord wing - but for a KR the info is incomplete and could be misleading in a bad direction - tail heavy airplanes are dangerous. On a KR2 built to plan, the net taper (sweep) on the outboard wing is notably forward, thus the overall CG location is displaced fwd relative to the calculated position of the centre section. The builder that establishes an aft CG limit of x% back from the LE and measures this on the centre section will be have a CG aft of what he thinks - maybe as much as 2" further back. OZ's statement is correct: "a wing with a 48" MAC, that is roughly 8-1/2" to 16-1/2" aft of leading edge". However, the mean chord on a KR /KR2 is not 48". (and the planform is not symmetrical) Take care Steve J
KR> AS 504X CofG - I wonder?
I guess that, more than anything, I was trying to figure out how Rand and Robinson arrived at their published CG range +++ Hey Oscar I found it interesting that your extrapolation came out within 1/2" of the RR numbers - almost as it they had also ignored the influence of the tapered outboard panels. Every informed opinion / pilot report that I have seen strongly suggests the same thing - the airplane gets unhappy with the CG in aft few inches of the range indicated by the designer. Maybe if the planform and true MAC were taken into consideration, the calculated CG range would be more acceptable. Take care Steve J PS - The Pete looks stunning - did it get dinged before or after you bought it?
KR> Fw: Yahoo! Photos - glasseyegav's Photos - My KR2 S Project
Hi Gavin Nice pictures. What type of foam are you using on the outer panels, it looks relatively light coloured - almost white? Take care Steve
KR> tri-carriage - split fuselage
The previous owner had to cut the plane behind the cockpit to get it out of his garage, and I wonder if someone has some views on the best way to join the two parts. + Andy You are on thin ice here, but the airplane can be joined without any hassles provided it is done properly. I would suggest that you get hold of Sybrand Strachen (he was with SAA and stayed in Boksburg) or one of the other "approved Persons" that knows his way around wood. You will have to involve one of them sooner or later anyway to get the bird signed off. It would be important to splice each longeron and diagonal (if applicable) with a doubler (splice) tapered at 1:10 (or 1:12) on each side of the break. It is highly unlikely that you will be able to "scarf" the existing longerons, so glue them together as is (where they were cut) taking great care to keep things straight - then add the splices (with dual taper) of the same material /dimensions. (Remember to do test pieces with the same batch of glue and material) Similarly, it makes no sense to try and scarf the existing ply skin for insets. Hopefully there is space on the inside for a 75mm strip of good quality 45 degree ply (similar thickness or greater) that is scarfed on both edges to be glued (centered) over the join. If not, you may have to locate the skin splice doubler on the outside - not as bad as it first sounds if you consider that the ply is under 3mm and the taper can be as flat as you wish (typically 25:1) provided you have the full depth width for the required distance either side of the join. There may be a composite solution for the skin join with a few layers of cloth resin inside and out - get advice from someone informed. It is not necessary to go for "belts and braces" - that would just add weight. In essence - a) ensure the continuity of each longeron (4) with a doubler (tapered on each end from 5/8" to zero over 6 to 8") PROPERLY glued. B) Similarly, ensure the continuity (of the forces within) the skin by joining them as above. Groete Steve J Lusaka
KR> Avgas cost
I am starting to feel a whole lot better about the fuel prices in Zambia (Africa). About the same as BC - hovers around US$1.00 per liter - maybe 0.05 one way or the other - close to $4/ US gal. Car fuel is generally about the same as Avgas, so no point in bothering. Steve J
KR> KR annual
Larry F = and had the prop off to rotate one bolt hole ++ Why Larry? Easier hand starting is all I can think of? Steve J
KR> Grove gear
There are some pictures on my web site. Easy installation ( I did not say inexpensive). Hi Bernard What is the blue plug that is visible on edge of the landing gear leg? Thanks Steve J
KR> Grove gear
For $100 extra Grove will drill the brake hydraulic line/passageway (gundrill) through the gear legs...makes for a neat setup. +++ Thanks Bernard. Never knew about gundrilling before so I had a quick look around the web - amazing equipment, I am pleased that I now know about it - thanks. I presume that they drill the passageways in the flat metal and then bend the leg to shape. Steve J
KR> Wax and PVA
Silicones have to be the worst, seems that you can wash whatever the part may be till the cows come home and there will still be a small amount left behind to screw up an otherwise perfect job. ++ I learnt all about this when some idiot picked up my "clean cloth" to shine up his motorcycle saddle - using a silicon based polish. I could not figure out why my paint job was going horribly wrong. As it turned out, I had used that cloth to wipe down just before spraying. 20/20 hindsight. After much agony, this is what I learnt: Keep any polish, wax, Lube, etc. that contains ANY silicon well away from anything (or any place) remotely connected to spray painting (including any rags that may be contaminated. Many of the aerosol magic lubes, penetrating oils etc. are suspect - check the contents (read the can) If you have contamination evidenced by small craters or "fisheyes" forming in the freshly applied paint (the paint is actually being rejected by the surface) - the normal reaction is to suspect water or oil from the compressor. DON'T sand (water paper) the area as I did, hoping to sand away the problem - this actually spreads the contamination and embeds the silicon into the surface making things even more difficult. There is a solvent that will remove the surface contamination. It is expensive and difficult to find, but it works if you wipe down two, maybe three times using a clean cloth literally with each wipe. (I use paper towels). Main problem was finding a paint or body shop that was aware of the stuff and would sell a small quantity (one pint or less). There is also a spray additive - a few drops in the gun will do the trick. Also not cheap and those who have (sell) it are secretive as to what it is - always got mine in a glass jar with no label. Some say it is the same stuff as the cleaner - I don't know, it may even be cold tea for all I care, but wiping down with it, plus a few drops of the additive in the gun will solve the problem. I have come to believe that you have everything over there (in the US) -probably manufacture the stuff - so if I can find it in Africa, you will no doubt have it there. Steve J
KR> KRVair variant
he has posted one of the pictures of his KR/Corvair variant on the Jan. 5 "open email" page on his website + Hey Oscar I have been staring at this that for a whole day now - looks good, but I don't see the KR connection - looks more like a fold-a-plane approach. Can you cast any more light on the construction? Steve J
KR> KRVair variant
In other words, it seems like William is building a Vision that looks like a KR and powering it with a Corvair. +++ Thanks Oscar All of a big sudden 1 + 1 = 2. I am a big fan of Steve Rahm - just that I am not comfortable with composites. (it's an age thing). There is (was?) something brewing somewhere called a Corvair Personal Cruiser - based on Rahm's rationale and Wynne's engine - it would make great sense if they are working together - only good things will come from that. Pity It only has one seat and will be made of plastic. Take care Steve J PS - you have been faffing around with that Squirrel for ever now - whatsup?
KR> Conversion
Probably more information than you wanted to know. -Jeff On the contrary - this is the most informative (and informed) answer I have seen to this question - thank you. Steve J
KR> The gospel of Bingelis
Did you sand or file all rib and bulkhead edges lightly? Have the plywood edges of the cantilever spar been chamfered? I noted this statement in his article on ply skinning. I can only assume that this is some form of stress relief or riser avoidance - can anyone cast more light. Regards Steve J
KR> KR-3 twin - It is real (or something very similar sure is)
And if you believe that, then Santa Claus is no stretch of the imagination either! I have the pictures - and it is flying, 2 VW motors /fixed pitch propellers. If anyone with a web site would like to post these photos, let me know and I will forward. Have a great festive season and take care on the roads. Steve J
KR> Braved to cold today.
I just wonder what the wind chill was behind the prop while I was doing that... I spent six hours out in the cold with my plane today and am very close to being ready for that first flight. ++ A brave man indeed Mr. Jones. I am excited for you and looking fwd to your first flight report - this is one of three airplanes that I sort of feel that I know intimately - I have read these web sites so many times over. Don't rely on memory - make notes and check everything three times. When I was in a similar situation I had a small pad of yellow POST IT's (2"x2") - I would make a note and put one on whatever needed remembering. The next secret is a note pad and pencil next to your bed - always. You WILL wake up with something on your mind - write it down right away, then have a P and go back to sleep. Good luck. Steve J
KR> Fuel Management
Phillip, I'll probably be judged a pi$$ poor pilot with my hair on fire but in the Bonanza, I routinely ran the aft tank dry +++ After reading the AvWeb article years ago, I took to doing exactly this on my PA32. This airplane (single) has 84 gal spread over 4 tanks - so without some care a situation often arises where you have 2 hours of fuel on board, but it is spread out between 4 tanks - all showing something near to "Empty". Fuel is often not available at a destination where you expected to top up the tanks, so you have to push on to the next stop. Nothing worse than being 10 minutes from landing, knowing that you have 60+ minutes of fuel - but what you can see is 4 tanks all on E. I took to running the tip tanks dry if more than two of the tanks were under 1/4 - that way I could be confident about what was remaining, plus I knew exactly which tank to select if there was a sudden surprise. HOWEVER - this is all fine with motors that will happily windmill all day (even at approach speeds) giving the driver plenty of time to change tanks and fire up all the pumps and fiddle with things until the motor is happy with the mixture and starts making nice noises. VW (and Vairs I suspect) do not readily windmill - they will stop dead if there is a fuel interruption for more than a split second. Let the experts speak - but my humble view is to avoid any fuel interruption on a High(er) compression engine. Higher RPM means smaller a prop (less leverage) will not help matters - neither will a re-drive. Steve J
KR> kr wings
No big deal, but a thought that may be maybe worth expressing. My concern with pre-fab wing skins (any wing skins) is the quality of bond with the spars. We need to remember that the airplane is literally being picked up by the skin of its wings (well 2/3 of it is). That may not translate to a great force per sq. ft - a typical KR has a wing load of maybe 10 lbs /sq. ft. At say 4G that is 40 lbs /sg Ft - so maybe 27lbs of actual tug on each square foot of wing. We know that the load distribution is not even over the entire wing and the bit covered by the fuselage is counted, but carries zero aerodynamic load, so some areas must handle a bit more - say 38 lbs /sg ft for those parts in a heavy G turn /pull-up. On the face of it, no big deal - that is a mild 1.3G load for a piston twin. Consider the KR wing structure (below the skin) and imagine dividing the top surface of the wing into 1' x 1' squares and screwing a cup hook into each square. Turn it over and hang 38 lbs on each of the 80 or so cup hooks. How comfortable will we be with the bond between the skin and the spar(s)? How about coming back and hanging these weights on the wing after the bird gets to be 20 years old and sees many great gatherings sitting in the sun. The point is that the combined load is transferred to the wing structure via a much smaller area - for a KR this is essentially the spars. The COP moves around a lot, but typical numbers would suggest that the main spar carries the bulk of the load - particularly under high G loads when the COP tends to sneak fwd - maybe even ahead of the main spar. The typical, KR main spar (top surface area) amounts to maybe 2 sq ft. that could well be carrying up to 700 lbs or more. Still not a very big deal, that is only 700/288 = 2.4 lbs /sq ft, but we do need to keep this in mind when bonding the top skin. With his wing skins DD suggests that we taper the spar in section only and leave the plan view (width) constant for more glue area Have a great Sunday Steve J Mark J - Y Haaa (hee haw) ?
KR> Lift - BS debunked
Jeez guys - never wanted to start a big issue here, just felt it important to stress the importance of the skin /spar bond - it has killed a few folks and it will probably kill a few more. I would be happy if I can do something to prevent just one future accident. I considered leaving it alone, but I have seen so many constructive contributors give up that I do feel compelled to stay with it a bit longer. Let me be clear - I do not feel compelled to comment on everything that is said - even when I know little about the topic. I can happily do without defending my earlier post with what is really basic stuff, but it is important to me that this message gets across - is that not what KRnet is all about? Some folks seem to feel obliged to have the last word and that would be great if they would build on the post and develop the point - add some value. In this case an important point may get lost in a meaningless exchange - so let us dump the conjecture and opinion and deal with hands on, seeing is believing, raw reality - OK. Please - take a desert spoon and go to the sink. Open the tap until you have a nice steady stream of water. Hold the handle (stem?) of the spoon gently between two fingers, with the scoop hanging vertically down - the bulge facing the running water. A bit like the top of a wing about to enter an air stream. Slowly move the spoon closer until the bulge contacts the running water. Get the message? I really need say no more. Orma, you sincerely said you were out to learn and I would be really pleased if I can contribute something to that. Do this little experiment and you will immediately understand where that 2/3 of lift comes from. The spoon will be aggressively "sucked" (tugged?) into the stream and you will have no doubt that 2/3 of the weight of your airplane is being suspended by the upper wing skin - sucked into the air. The spoon has no "bottom surface" that is being influenced by the flowing water, so the under-camber aspect is NOT at work here. We could leave it there, but for those who are now curious. The spoon has no "bottom" as such, so that blows any verbiage about: "the airflow being increased over the top creating a pressure differential from under to over causing the air on the bottom to push up into the now low pressure area above the wing" I read the above a few times and I have no clue what he is trying to say - with great respect, I honestly tried. In any case, there is no water moving under the "wing" in this demonstration. If the stream of water from the faucet was in fact a thick sheet of water, the spoon would continue to be "sucked" through the water until it came out the other side - the upper "camber" is developing "lift". >From airplane to airplane (depending on configuration, loading etc.) the horz stab may or may not be contributing to lift and some parts of the fuselage may sometimes contribute a bit (it is reported that the GP4 canopy generates 400lbs of lift??) but for the purpose of this discussion, the wing provides the lift. The following is not my opinion, speculation, assumption or a product of thumb sucking - it is well established, simple, basic old hat fact. Approx 1/3 of the lift produced by a wing is generated from pressure under the wing and the other 2/3 of lift is created by the top surface of the wing. You have just proved the 2/3 bit with the spoon. We have all stuck our hand out the car window at 50 mph, so we know all about the 1/3 bit. (Even then, we are actually also seeing some of the 2/3 bit). If you want, you can do a second test to really make sure that your airplane is being sucked into the air (by the top skin) even it there is NO BOTTOM SKIN. This is more difficult to explain. This time we deal with air flow, not water. Take a sheet of typing paper and hold it by the bottom corners, one corner in each hand, between two fingers - sort of like you wanted to read it without smudging it. Bottom corners OK - the page is above your fingers. Try to hold the sheet near vertical (like you were reading it), then without changing the position of your hands, allow the paper flop over backwards (away from you). The bit you are holding is nearly vertical and the rest of the sheet is sort of hanging backwards over your hands - right. Now blow over the curve of the paper. Amazing how it rises up. The harder you try to blow it down, the more it rises up. The flow of air is "sucking" the trailing paper up - even without any airflow around the "bottom". The lift created by the top surface of a wing is indeed a function of Bernoulli's Law - also known as the venturi effect. The vacuum created in a venturi (Bernoulli's Law) is substantial, venturis were developed in days gone by to power vacuum instruments. Call it negative pressure, call it vacuum, call it what you like - in simple terms Bernoulli's Law is all about "suction". We really could leave it alone now, but in the interest of completeness. I am not
KR> Lift - BS debunked Part 2
I had an interesting email (off-net) from one of the fellow netters - thank you sir. I have been around since 1949 so I am aware of most broad strains of rationale regarding wing lift (and then some). When we get down to brass tacks and sort through the 10-100, most of the various hypotheses actually support reach other, but I hate it when the simple facts (truth) become distorted and difficult to comprehend because of an over supply of words, theories and ego. There is no reason why the regular builder /pilot should not have a reasonable understanding of how these things actually work (and let the academics go debate the higher sciences to their hearts content) The demonstration that placed everything into perspective for me was really brilliant and would not be that difficult to replicate. This is a highly visual demonstration that really settles all arguments. Maybe someone teaches the subject or would like to make one for the next hangar meet. There is much to be learnt from this, we can even clearly see how the centre of lift (pressure) moves around as the angle of attack varies. One simple drawing would tell it all, but let's see how far we get with words. The demo comprised of a wing section with a chord of about 30" and a similar span - no more than a short piece of typical wing with a simple 15% section and not much else - no spars etc. There was a series of holes down the centre of the wing, all along the "rib line" from front to back, top and bottom. Each such aperture was connected, via a flexible tube, to a glass U tube that was half full with colored water. By subjecting the wing to an air flow, it was possible to visibly display the actual degree of pressure (positive or negative) that the wing surface was experiencing at any point along the chord. The glass tubes were side-by-side, so the resultant image was almost like a graph. The lift profile (water height in each tube) formed a parabola starting just behind the leading edge, progressively increasing to a peak at about the 30% aft point - then tapering of to zero at the TE. This was a vivid and visual, live view of the lift "sucking" away at the surface of the top skin. It was also possible to vary the angle of attack and observe (in real time) how the peak moved fwd (and higher) as the AofA increased. The area of the curve encompassed by the points on the parabola sort of gave a pictorial representation of the quantity of lift. Similar results were displayed in the second set of glass tubes displaying the pressure from each point under the wing - except that the parabola was inverted, flatter and approx 1/2 the area generated on the top of the wing - really. I have seen illustrations of something very similar in a book - "Flight Without Theory" - I think the author is AC Kermode (sp??). This publication has a similar illustration of the span-wise lift profile at the Clmax - very useful for someone trying to figure out some wing tips to actually see how little lift is being generated in this zone (and how useful some winglets may be) A similar, simpler model of smaller proportions could be made out of some scrap 015" Alclad, ABS plastic, heavy card, 1/32" ply, etc. With some fish tank tubing, a dish of water (with food coloring) and a leaf blower - we could have a model that would serve well to illustrate the point. Please remember - this is all about the importance of the bond between the top skin and the spar(s). One last plug at this comes from my RC experience - I am sure many netters will relate to that. It was a sport model with solid foam /balsa wings that were covered with one of the glossy heat shrink materials. This airplane flew really well, but every so often it would suddenly enter a diving turn - always to the same side. Obviously everything in the radio dept. was suspect and gradually swapped out until it was painfully obvious that I had a strange aerodynamic problem. During yet another test session (with high pucker factor) one eagle eyed observer said something about one wing puffing up just before the airplane went berserk. The penny dropped - I recovered the wings making sure that the covering was well bonded all over. Thereafter the Mongrel was a treat to fly. The lift was sucking the covering away from the wing on one side only and acting like a massive airbrake, spoiler and aileron all in one. Take care Steve J
KR> The mystery of lift
well I really don't care, as long as the plane fly's +++ I agree - that is what counts. Have a great week Steve J
KR> Weight and Balance
I say do the preliminary W before making any changes, because, otherwise, you will just be guessing. + You can always get some idea of the CG location by seeing where it actually balances. Don't poke any holes in the bottom wing skins, but gently resting it on two trestles will give you a good indication. Make sure there is a spar, ply rib or something where it rests. Some scrap foam will help here. Not sure I want a battery anywhere behind me - just in case there is a sudden stop. Steve J
KR> Props
What are your thoughts on having two bolt patterns on the same prop? + Stop stalling (and muttering about the weather)- go fly that airplane and give us the KR grin. (and Ye Ha)
KR> AS504x wing sections
Happy Friday guys Mr. Langford (alias Flinkdink, AKA long ranger), please straighten us out on the above topic. My KR2 plans have only 2 wing sections, both RAF48 - one is 48" chord (for the centre section) and the other is 36" for the tip. According to my plans, these are the final dimensions as the urethane foam is sanded to these templates. The Ashok sections generated and made available by your kind self and others offer the 48" section, but offer a shorter section for the tip - closer to 30". No doubt a good reason, but I am missing it. If you have a moment, maybe talk about the differences in the selection of airfoils included in the pdf file. Neat idea to express the section outline with two lines - any builder that has screwed up will appreciate the value of the back-up line. Regards SteveJ
KR> AS504x wing sections
Ashok designed that airfoil specifically for the KR2S ++ Thank you - it has now finally sunk in that there is a bit more to the 2S than a fuselage stretch, I had better get the supplement. Take care Steve J
KR> AS504x wing sections
You 2S guys please adjust my thinking if I am wrong. The 2S is not any different than the 2, just Stretched. Certainly not the airfoil. + That is what I thought and you are mostly correct Dan, but I gather from Mark L that the wing plan form is also subtly different. (Tip section) The Ashok section were never provided or even accepted by RR coz that precludes the builder buying the pre-fabricated wing skins. Take care SteveJ I guess we should here a big yee haa from other Mark anytime soon??
KR> canopy
Doe's anybody have an email ad or ph# for Todds canopy Thanks Bill Email: bsilve...@aol.com Cell # : 954-579-0874 Web URL: http://kgarden.com/todd/types.htm
KR> spars
What's the common thinking about making the main spar one piece? +++ I share your discomfort here John, plus a few others. I accept that the KR spar is stronger than a brick outhouse and there have been no reported failures etc. etc. It still worries me. As ever, I express my views in the hopes that the more informed among us will step in and put me straight. It is not so much the strength of the WAF's that concerns me, it is drilling all those holes in the spar (cap). Even the landing gear mounts require holes drilled in the upper and lower spar cap at the very point of highest load (almost). I cannot bring myself to do this - my intention is to add a wider pillar between the caps where the undercarriage mounts, add a 2mm 4130 "back-plate" behind the spar - then drill the mounting holes through the pillar - not the spar caps. This way the legs are sort of clamped to the spar without any holes in the load bearing caps - maybe even one size up on the ply web between the legs (and the necessary precautions against stress risers). I may compromise by having holes in the top cap (no plans for any inverted flight any time soon). The above approach is probably not acceptable for the WAF's, so this is my chosen way to deal with this particular concern and a few other short-comings at the same time. I plan to build a bent, laminated spar with the dihedral starting at the fuselage (as suggested by Mark L on his web site). Riley Collins has already done this and it worked out great. The next trick is to relocate the WAF's outboard to about half span. I.e. the centre section spar is "bent" up just as it passes through the fuselage side - and continues further out. = the load on the WAF's is now substantially reduced (shorter moment) so using the same (or similar) WAF design and material will substantially improve the margin. = doing away with the crank wing may look nicer to some of us - I personally like the way a KR looks anyway. = Fuel tanks (centre section) will drain better. = Flaps of better proportions. Take care Steve J
KR> Bent Spars = Big Flaps?
a flap that starts at the fuselage and extends outboard of the stub wing. This creates the potential for some very effective flaps. + One of the primary idea's behind the bent spar is to move the WAF's OUTWARDS. The centre section is then one-piece (canting up for the dihedral where it exits the fuselage) and stretched to about mid span. Then you have ample room for flaps on the centre section (and ailerons on the outboard section). QED. The rear spar is the snag - you are correct is assuming that it sweeps at the WAF intersection. On my dwgs the rear spar now sweeps from the centre line of the aircraft with a constant sweep (and dihedral) to the tip. It will mount to the fuse much the same way the GP4 rear spar mounts. For the information of our intrepid watchdog (with the short bio) - I am not crazy and I have no death wish. Everything that I do from the main spar to the elevator hinges will be checked by someone who knows exactly what he is doing. Steve J
KR> Leaders or Followers - long
The designer during the design and structural analysis process considers the holes, both locations and diameters, and load being applied to determine the final size requirements. To continue the design process of the spars, the designer determines the landing gear strut load conditions. The sensible approach to building an airplane (if you really must) is surely to buy plans or a kit from a reputable designer and build the airplane according to plan. Fact is, few of our species want to go this way, including (with respect) Ken and Stu - in fact, if they had followed this sensible logic when they each wanted an airplane, the KR would never have been born. No matter how strong your feelings may be, getting wound up, insulting and cussing will not achieve anything other than cause rifts - and silence those that already say very little (generally the smart ones who's input we really need). It is sound advice that tells us NOT to mess with things unless we know precisely what we are doing, cannot fault that. For me, even better advice is where to find the skills you need to come over and help you mess with whatever you want messed with. I am sure that is what R did, there is just no way they used the core design "as is" for all the products. What they came up with has proved to be adequate - not sure when Jim Marcy got involved, but if they did not know, they sure found someone that did, just like we can. To get a neat KR off the ground is going to cost at LEAST $10k plus a few years of dedication. Another $2k ?? for the right skills check the changes that make it perfect for you is a bargain. The original KR was a copied from the Taylor Monoplane (designed in 1956, 1st flight 1959). I don't know what was available in the way of epoxies, polystyrene, urethane, Dynel etc. 10 years earlier, but we can be sure that when the first KR was conceived, Rand and Robinson changed more than just the name. They seem to stay with the basic configuration, dimensions and wing section, but they took off the blinkers - history says that even their U control model airplane experience came into play - I think this is wonderful, they were true leaders in experimental aircraft. The original Monoplane had a fixed u/c similar to that on a DH Chipmunk, but the KR1 rev 1.0 emerged with a retractable landing gear. A clever concept, but one resulted in many holes being bored in the centre section spar caps for the various pivots and locks. I am sure they did the necessary and "messed with it some" - none have ever failed. This 500lb Monoplane evolved along the same basic structure to become a 1,000lb, two seat, 200 mph (up to) airplane. Most of the completed airplanes have been stretched and widened with more power added and a higher gross weight. I have little doubt that John Taylor engineered (and probably tested) the primary structure to good old British WWII standards, but I sincerely hope that R messed a bit with the structure on the way to the KR2. The true contribution by R was the concept, the materials and method revealed to the homebuilder - FLEXIBILITY. Maybe that is why less that 120 Monoplanes were ever built, but 20 times as many KR's are flying (or in the pipeline). I am NOT trying to get up anyone nose here - just make the point that our kind (the species that will opt for a KR above all other designs) aspire and dream about how it will ultimately look - different - that is the very essence of this design (concept) and it gets worse every time another great looking KR takes pops up on my screen. . Telling them to build it like it is and leave well alone, takes (for me) a bit of the spin out of the airplane. I bet that each flying KR owner is very happy with his unique, very own airplane - after all, he made it that way. If he is unhappy with some aspect - he will soon take it out back and add a belly flap, nose gear, whatever. It is a scary thought that some builders may have unwittingly done something silly that will someday hurt them - I would hope that this forum will go a long way to preventing that. I have little doubt that the originators were responsible in what they did, and that the present design is adequate (structurally safe), but like anything, it can be improved. It is this builder's intention to change everything that does not suite or appeal to his vision - but to ensure that each change is scrutinized and approved by someone competent. Test wing spars will be built (using white pine, builder's ply and carpenters wood glue) and loaded to failure. It can be done in a weekend, costs very little, gives some practice, and settles concerns. Yes, I know there is a bit more to it than that - this is just one for instance!! Have a great Sunday Steve J
KR> For the season
but you're gonna lose an engine >on takeoff." ++ Brilliant
KR> PINK SLIP
Take care and good luck Be a real devil and beat Flinkdink to the blue yonder
KR> Don Reid
Hi Don With reference to the "Specs and Mods" comment on your web site: In the narrative you mention a stretch of 5" fwd and 6" aft for a total of 11" over the KR2S - thus a new length of 16'11". Your root chord is 4" greater (48 to 52) so maybe another inch or so in the distance between the spars and thus the overall length - so maybe a total of 17'. In the table comparing the KR2 /KR2S /KR2XL you give a length of 18'6" for your airplane. I am missing something here. Thanks Steve J
KR> RE:GARMIN
All that Mr. Irwin did was to point out the reality to us. Everythi8ng that has been said regarding the legitimacy of price control etc. is valid and true. What Mr. Irwin did was to intercept privileged information on this site and drop one of the members (and his supplier) in the dwang. A few weeks ago members were discussing the tax laws in various states. How would you feel if you discussed (with your buddies on the net) that you had not been taxed on your airplane - and a week later the inspector arrived at your door with a fine, claim for back taxes and a tax bill because some other righteous citizen felt honour bound to tip off the relevant authorities. This is a private forum that is maintained and offered at no cost and (as far as I am concerned) nobody has any "rights" to do anything other than learn and contribute. Steve J
KR> How much width is enough?
Anyone not sure how wide to make the boat? It is generally accepted that the standard KR cockpit is just not wide enough at 34". I am a relatively "wide" guy, so I read everything I could find, particularly the opinions of the guys that were already flying their airplanes. I also noted what more recent kits /plans were doing in this dept. Still not convinced, I did all the usual stuff arranging the dining room chairs in various ways and measuring everyone that walked by. I eventually convinced myself that nothing less than 47" would do. The well stretched fuselage (15' back from the firewall) helped to disguise the bulge in the fuse which moved aft to about shoulder position. All was well. Then I settled on the Jabiru engine and everything changed. The cowl only needed to be 24" wide - that is 7" narrower than the VW (6" smaller than the Corvair). Now the bulge looked really silly - the nose was just too pointy. Ishh This last week I travelled down to the lower Zambezi to recover a crashed C172. The wreck was transported back to my house where my kid is stripping it down for the insurance company. Today I was looking at it - the cabin really looked real narrow. I found a tape measure and checked - 39" at the widest point (shoulder position). That really shook me guys - I was trying to go 8" wider than a Cessna 172. Hope this saves someone some sleep. Steve J
KR> 56ML Rudder Pedals
Morning Mark I guess you are into the sort strokes right now, so stay focussed and make plenty to-do-lists - don't rely on memory for anything. When you have a spare moment; >From your rudder pedal construction page: Quote - The angle which serves as half of the pivot was bonded to the back of the pedal with some incredible stuff sold by Tra-Bond. Mark Lougheed sent me a sample, and it's tenacious stuff similar to JB Weld. Saved a few ounces on bolts and nuts here! - unquote. You have three small holes drawn in on the outer pivot and pedal but from the above it would appear that you are satisfied with the bond alone - no fasteners? Thanks for the .pdf - this is exactly what I will do including the improved brake pedal retainer idea. I will however splash out on six 4-40 countersunk bolts and nuts. On your engine page you discuss areas where you could have saved weight (the 20-20 hindsight thing) reduction - I was surprised at how much could be safely trimmed - very encouraging. I plan to use the 18%/15% wing section in precisely the manner you would have preferred (bent spars) except that I intend to move the WAF's outboard to the flap /ail intersection. I understand that you switched from RAF48 to the 15% NLF(1) and then to the AS5046 and this resulted in a wing spar of unnecessary proportions - what would you do if you (when you) do another wing (in terms of laminated cap dimensions?) It is understood and accepted that my results may vary. Good luck. Steve J
KR> Eduardo's plane & website
A visit to Eduardo's website is worth the time. http://www.kr2-egb.com.ar/ He is building an amazing plane. Exceptionally nice website too. I can see why you get so excited about it. ++ I tell ya Frank - if I could just get my mind around this dissimilar stiffness thing. According to at least one reputable composite guy, this is a problem. I am sure there is an answer /solution, but in the mean while it really worries me. Imagine a 2S with the popular stretch in length and width; fuselage constructed in the Eduardo style; incorporating Flink Dinks' DAISNAID laminated, bent wing and a Vair with 120 ponies. Isshh man, the ultimate KR Steve J
KR> HS Weight
If anyone has the weight data, I would appreciate it. +++ Eduardo reports 6.2kg (13.64lbs) with a NACA 63a008 and the plans style hinges
KR> Gathering photos, finally...
they are reduced and compressed by an average factor of 120x, so the slow modem guys won't choke on them Thank you Mark - highly motivating What a treat it must be to actually be around these folks and airplanes.
KR> Glass fuse
I think Eduardo's idea is the strongest, incorporating the best of both construction methods. This could help keep ones cost down if wood is hard to get ++ Acceptable grade plywood is a problem for me - Eduardo's method really appealed to me as a cost effective solution that also produces a pretty elegant fuselage - BUT, the concern I have with this relates to the difference in relative stiffness between the wooden structure and the glass /epoxy skin(s). Extract from Zeke Smith (On Composites): This illustrates a principle that carries into practical composite aircraft design. Some designs which use mostly E-glass fiber make use of carbon (graphite) fiber for spar caps. Carbon is much stiffer than glass, so the carbon will carry nearly the entire spar cap load. If any glass is used in parallel with the stiffer carbon, the glass component is essentially wasted because it will never experience enough strain to carry a useful load - the carbon fiber gets nearly all the load .. Eduardo created a wood structure that (I think) is potentially as strong as a regular KR boat except that he replaces the ply skin with a pseudo composite structure. To what extent will the difference in stiffness here cause the inadequate wooden structure (no plywood skin) to take the load - as suggested by Zeke Smith? Even if the composite component is actually strong enough to do the job without the wood - maybe the wood takes the load first due to "stiffness". Something here is certainly along for the ride contributing only weight. The Vision fuselage is based of a Last a Foam core with glass skins to form a classic 6mm (1/4") sandwich structure. The wood structure, as you know, is purely a "mould" that is discarded after the fuselage shape is established - thus no embedded wood. My own idea of getting the "best of both worlds" is to follow Eduardo's method but pursue the Vision end result by using a lighter wood structure (3/8" square) that will remain embedded (like Eduardo) but without any gussets or blocks - for that matter, even using lighter white Pine or Poplar, but with an adhesive that will allow the joints to flex or stretch later. Filling in with 1/2" core material leaves some surplus to sand and the result is a fast, straight, smooth, rounded shape (as per Eduardo). The skin thickness is selected as if there was no wood. We are taught that a thicker composite sandwich is stronger for a given skin strength, so the resultant KR fuse of 3/8" sandwich should be stronger (than a 1/4" sandwich) plus the embedded wood (3/8" sq) will improve the mean shear strength of whatever core material we use. It sounds like loads of extra work, but it suits my workshop and my style - the question is - will it work??? Steve J
KR> KR - 56ML - HS Update
Steve, below is a message I sent to KRnet about 5 years ago . After my new ones were built (they were lighter anyway because of a little design change) I started wondering how strong the old ones were, and tested them to failure. The glue joint isn't where the caps separated... Thank you - should have known you would figure a way. Pity my table saw does not have a controllable tilt adjustment (more like unlock /reset by hand /lock method), but I liked the other idea of using an electric hand-held plane (mine is 3" wide) with a two angle rails to get the progressive angle change Would you share the design change or maybe its obvious from the relevant construction page? How did you load the first spar and how did it fail. I presume that it was un-supported in the torsional sense so it may have twisted. Take care Steve J
KR> Glass fuse
You worry me when you say it is not good !!! who is zeke Smith + Hey Ron - As the man always says, your results may differ. I discussed my concerns with Eduardo (this took some time as he speaks Spanish and I speak English). He certainly is a bright guy and appears to have done his homework. Everything else he has done is near perfect, including anodizing his ali parts and making up his own legs and leg attachments, fuel tanks etc. One other South American (Leo, he speaks English) is doing similar things with a GP4, in this case the wing was originally designed for a ply skin, but Leo is doing a KR wing type skin, but staying with the original design spars. http://www.geocities.com/leoadrena/GP4.html Leo built a nice KR before, so he has been around DIY airplanes for a while. Zeke Smith has written various books and articles on composite structures - I see him as knowledgeable in these matters. If he perceives a problem with mixing E-glass and Carbon fibre in the same lay-up due to the differences in stiffness (as suggested in the extract I included) - I must wonder to what extent the same problem will be present in Eduardo's Structure - he is mixing ply with glass. For that matter, how wise is it for Leo to build the wing sub-structure (spars /ribs etc.) according to the plans and then completely change the wing skin from ply to mould-less composite (not even a true sandwich)? I don't know, but my hopes are that one of the netters has an informed opinion and will share it with us. My strong interest is with Eduardo's way - I suppose the question really is which is "stiffer", the spruce frame or the foam/glass composite. If the Composite component of Eduardo's airplane is stiffer and takes the initial load, all is well (if the glass bit is spec'd to do the job.) The spruce frame goes along for the ride. If the spruce frame is stiffer and loads up first - it may not be strong enough without the ply skin and fail. We both seem to like his approach, so let me know if you learn any more. Take care Steve J
KR> Glass fuse
Hi Doug I really like Eduardo's way of making a KR fuse and it would suite me just fine to see things the same way you do. I would like to start my project in January and this is one of the few outstanding issues. I cannot imagine anything worse that looking at a complete fuselage or wing etc. and realizing that you opted for a bum idea /material /technique and created a pile of junk. My reservations stem from Zeke Smith's teachings - what are your thoughts on that? To reiterate, he opens the relevant chapter with this comment: Quote: The following simple puzzle illustrates the effect of using two materials of different stiffness in the same structure - end quote The punch-line of the lesson is: Quote: This illustrates a principle that carries into practical composite aircraft design. Some designs which use mostly E-glass fiber make use of carbon (graphite) fiber for spar caps. Carbon is much stiffer than glass, so the carbon will carry nearly the entire spar cap load. If any glass is used in parallel with the stiffer carbon, the glass component is essentially wasted because it will never experience enough strain to carry a useful load - the carbon fiber gets nearly all the load, just like in the puzzle with the stiff chain and the soft bungee - end quote. In the true spirit of KRnet, we all strive to lean and understand more about the tools, materials and techniques we use. To progress this discussion, it would help if you addressed the particular comment that you do not agree with so I can either learn from your input, or clarify my position and take the discussion to the next level. This way we will ultimately conclude the discussion and one or both of us will learn something (along with any other netters that were interested). With some luck we may even lure one of the informed netters into setting us straight. As above, what is your reaction to Zeke Smith's teaching? Take care Steve
KR> Embarrassing Moments
Building airplanes is like raising a family. By the time you are finished, you have finally figured out how to do it right. That's why grandparents are so neat!! ++ Oh so very wise - thank you Jimbo I will make a plaque with those words (for when I am a gramps) Have a great weekend Steve J
KR> "Blowing" your own canopy - it can be done
Anyone out there with plans or ideas on blowing your own canopy? The general recommendations tendered on this topic so far are probably the best advice - go buy one. However for those that really want to make everything or have an abnormal requirement (like my 44" width) - have a look at: http://www.kr2-egb.com.ar/ Yes - it's good old Eduardo again. Under the heading "Cabina" he gives a detailed account of how he made the mold and formed his own canopy frame plus windscreen and side panels (for a gull-wing door set-up. Absolutely brilliant. The comment is in Spanish - I used a web translator (http://translation1.paralink.com/ ) to give me an English text - I have made MS Word pages with text and pictures for everything on his site and will be using this as constant reference during my build. Thank you Eduardo Take care Steve J
KR> HS Update
Welcome back Herr Langford What secret bits did you smuggle back for the Sirocco? The following extract from your construction pages (tail feathers): The tapered spars were created on the tablesaw with the same tapering fixture that the newletter printed a few years back. Simply put, it's a straight piece of 1x6 to which the spar is clamped using wooden clamps, at the desired angle. The angle on the blade was also gradually altered during tapering, so that the spars required no sanding to match the airfoil profile. This took an awful lot of thinking (mostly in mirror-mode) and ate up a lot of time, but was worth it in the long run. ++ Can you say a bit more here Mark. Any time spent getting this right will save gobs of time shaping and sanding the spars later (empennage as well as the wing spars), particularly with the AS sections. I am not convinced that what I am visualizing is right, i.e. - cutting a few inches; shutting down; changing blade angle; starting the saw; cutting a few more inches etc. You mention "required no sanding", so obviously no steps?? Would be nice if there was a way to progressively change the blade angle between the known angles during the cut. Take care Steve J
KR> Trim Indicators
I'll type Ray Allen into a search engine and see what I can find http://rayallencompany.com/index.html
KR> Cheap Carbon Fiber
Brian Kraut pointed me to a distributor for discount carbon fiber. The are offering 282 5.8oz CF in 60" width for $12.50/yard. ++ Can you please pass on the suppliers contact details /web address Thanks Steve J
KR> G limit - long
how and who came up with this rule? Is there any science behind it? No science at all, only BS. Most netters already know this, but just in case .. If the aircraft weighs 900lb, then 1G (gravity) is 900lbs. The rated load factor of 7G means the relevant part of the structure was tested /calculated to withstand seven times static weight - it can thus handle 7x900=6,300lb - that is what 7G means. You can literally put 6300lbs* of sand bags on the wing (properly spread out to represent the load) to establish the -G limit - or load the inverted airplane to establish the positive load factor. The structural strength does not change if we make it heavier, so the tested or calculated capability is still 6300lbs. If we add another 100lbs of structure, fuel, cargo, passenger etc., the MAUW will be 1000lbs and the G capability will be 6300/1000=6.3G (not 7-1=6G) If we add 400lbs (increase the MAUW to 1300lbs), then 6300/1300=4.85G (not 7-4=3G) Apply this rationale to a Cherokee typical MAUW of maybe 2000lbs and a load factor of +5.6G 2000x5.6=11,200. Apply the BS rule (1G /100lbs) 2100lbs reduces the LF to +4.6G?? The truth: 11200/2100=5.33G When we talk about load factors it is important to know: The aircraft has a CALCULATED load factor of +7G / -7G? Or, the aircraft has a DEMONSTRATED load factor of ...? Tested (loaded) to +7G with no permanent structural damage /distortion? Or, tested to destruction, i.e. failed (or permanent damage) at +7G (often referred to as the ultimate load factor). Everything in /on the airplane is subjected to G forces, not only the wing. A fuel tank could pop out the bottom of a wing if the mountings are not capable of restraining the load of the tank plus fuel at X times its static weight. Counter-balance weights (elevator) were discussed on the net recently - they must also be able to withstand any G loads that the airplane may be subjected to. We generally see G loads as pilot induced - steep turns, pull-ups etc. The discomfort of G forces will keep the pilot aware of the effects - may even cause him/her to black-out. (The blood trying to get to your brain is also subjected to the same G load (acceleration). G loads caused by turbulence scare me, they are invariably unexpected and can be very harsh. They are instantaneous, leaving no time to take any compensating action. That is why store bought airplanes have a placarded manoeuvring speed (* not strictly true - some of the wing weight will be excluded) Have a great weekend Steve J
KR> Looking for basic specifications
Hi Joe As Scott says - many of the lads are on their way to the 2004 gathering. In the interim, the sites that proved very valuable and interesting for me: http://home.hiwaay.net/~langford/ http://www.erols.com/donreid/kr_page.htm http://mywebpage.netscape.com/n886mj/homepage http://kr-builder.org/ A particularly interesting site and my favourite: http://www.kr2-egb.com.ar/ It is all in Spanish, but the pictures are so good that it hardly matters. I copies all of his pages and used some web based free translating software to translate all the narrative to English - wonderful reference material and very inspiring. Take care Steve J http://www.freetranslation.com/ http://translation1.paralink.com/
KR> Rotax
My guess is that the cost of the Rotax may be a big reason they are not popular in Krs leaning towards the VW or a Corvair conversion. +++ Yikes - I see what you mean - $14k for 100hp. I really like the Corvair, it has (I think) all the characteristics of a very reliable and cost effective aero engine. Whereas I am happy to create every single bit of my airplane including the canopy, when it comes to the motor - I would really prefer to take one out of a crate. Several neat VW conversions available, but nobody seems to offer a ready-to-fly Vair. If there is a supplier, please pass on the email or URL. Have a great Sunday. Steve J
