KR> 912 ULS
HI, i'm after some info about installing a Rotax 912 ULS 100 hp in my kr2. I am replacing the Revmaster R2300, I am sick of spending more hours fixing the engine than flying it. about 150 hrs flight time and 300 hours repair time.what I need to know is, has any one out there have a 912 ULS in there KR2, what my concern is with the reduction drive at 2.43 equating to 2380 RPM at the prop would a 58" diameter prop be enough for take off, then in min cruise power with 2057 RPM at the prop is it still going to work, currently with the R2300 'when its going' I am getting 135 KT cruise at 3000 RPM.what I am guessing is with a 58" prop (max dia I can safely go) it would have to have a hell of a lot of pitch on it to get the engine loaded right, then with that much pitch am i going to have more trouble with the prop stalling say when trying to take off? prop manufacturer here in Oz. said that that engine and there prop would give me an estimated cruise about 150-160 kt cruise WOW!! if it works. I know its not the correct way to look at this but 2000 RPM at the moment i'm barely keeping the plane flying?If anyone has installed a 912 with a 58" prop what prop are they using, and how much success are they having with it.Another engine option I am considering is the new D-MOTOR LF26 specs look really good to suit a KR2, direct drive, 92 Hp @ 3000 RPM, water cooled, EFI, 88 Hp @ 2800 RPM for cruise,8 liter/hour 2.1 gal/hour for the yanks, (that near the doubles my fuel endurance), 67 kg ready to fly weight and its tiny and apparently very quite. and has down loadable diagnostics which can be sent to the manufacturer for analysis or tuning, and cheaper than a 912 'not by much'.
KR> Revmaster R2300
Hi all, I Thought I would put my two cents in about the Revmaster R2300 as I have one of these in my kr2, When I'm not working on it trying to figure out the bugs, when its running right it is a great engine, after about 18 months of playing with it I am now getting 140 kts cruise and 1200 fpm climb at gross , so that i think is pretty respectable, and can now not stress to much on it performing properly. But the problems I have had with the engine at times I've been ready to burn the plane! thinking I would never get this thing right. A few times in the early hours of it flying it I had to do emergency 180 turn backs on climb out as the engine was not going to make the full circuit, with CHT's going through the roof at 300 deg C+. (screen only only goes to 300 got there in about 10 sec from take off, and EGT's 950 deg C+. (last flight when the heads finally cooked). a list of the faults I had with it are. 1/ ign. timing set at approx 40 deg btdc, which cooked the heads within 10 hrs from new (timing was factory set!) with a timing light shown it was correct at the prop flange, but found it a with dial ind. on piston #1 while stripping the engine down. 2/ aluminium push rods 6 out of the eight failed in 40 hrs, now replaced all with steel ones (rod ends crushed into the alloy tubes) and yes they were rubbing on the push rod outer tubes . 3/. oil leaked out like a sieve every were since new, can never seem to get one to take up from out the back of the engine, 4/. constantly lapping valves particularly the exhaust valves, 20 hours ago had the heads professionally ground and re seated and just recently 3 exh. valves started leaking again and had to re lap (about 2 hours ago). and feels like i am adjusting tappets every 5 hours. temp figures:- CHT's on average in climb approx 180-190 degs C., 140-150 deg C in cruise 90-100 on descent.EGT's around 680-720 deg C, in climb and about 600 deg C. in cruise.Oil Temp about 60-70 deg C, pending on day temp.So the engine does run pretty cool and I am running only on 98 unleaded fuel, no ethanol. (cant afford AV gas over here or justify it.The engine now has 130 hours on it (with 500 hundred hours spent working on it!)And as I said earlier when its going properly it does perform very well, but the quality of manufacture does let it down! Or mine must have just been a Friday build.
KR> Revflow carby
To "Roger Bulla" everything that you described is exactly what is happening with mine, I can get it to run smooth at full WOT. on climb and really high EGT's, (and no its not on the lean side) then reducing the throttle into the mid range and low end, the mixture control is so far back its almost to the point of no fuel, an example yesterday for touch and goes I was doing is why I don't like it, was when I went to open the throttle approx 1/4" i forgot to richen the mix first before moving the throttle and I swear that if i hadn't have got onto the mix when i did the engine would have stopped and I would have been though the fence on the end of the strip, you need a throttle that will respond straight away at least with a small amount of throttle movement.Let me know how you get on with your Revflow Rodger, like you, i like the design of the revfow and alternate flow ram air intake, If i have to change carbs i also will have to reshape my cowl to suit.
KR> flying, KR 19-8322
I'd like to make a little comment about flying my KR2, Granted I have only clocked up 5 hrs on it now in the last 3 day since I started flying it myself, but all the hype i had read about while building it, with being a very sensitive if not over sensitive plane to fly is absolute rubbish! or I just got it right! I cant stay out of this thing!!! it has to be possibly the easiest plane I have ever flown! the mod to to stabilizer by stretching it's span 6" and cutting the span of the elevator down by 4" has really paid off! still light, powerful and responsive but by comparison to the fin and rudder which is pretty much stock to the plan very light and very easy to catch you out and to get in trouble with over control on the ground with the tail up, but comparison between elevator and rudder responses, elevator would be half as sensitive as the rudder but still just as powerful, if the rudder is anything to go by, If any one is like myself as a low time pilot and building one, I could not recommend anything better than the mods that Troy Petteway did to the tail, just wish I did it to the fin and rudder. Test pilot stated to me just before I flew for the first time that, he has never flown a plane that is so easy to 3 point land! and he is right! I could only imagine how sensitive the elevator would be if done to the plans. Would be very nervy on the first couple of landings until you got used to it.
KR> kr props
Thanks for the replies about props, test pilot flew the plane again this morning and the local plane legend was there again as well and everyone agreed that the prop needed to be trimmed down and after what a few of the kr netters had suggested also, I bit the bullet and trimmed 1/2" off each tip. now my static rpm has increased by approx 80 rpm, from 2370 to 2450, not quite as much as I had hoped. test pilot will take it for another run tomorrow to check to see how much more i will gain in flight. (i hope i don't lose to much on performance!)If all goes well, hopefully I will get to take it up myself tomorrow as well for the fist time, I did do a couple of runs down the strip this morning flying it approx 10' of the runway, love the aileron response just need to get used to the elevator, must have been funny to watch when i was trying to settle back on with ballooning, over controlling with elevator.
KR> kr props
Hi all, does any one have any advise on props, my kr2 has now had its second test flight on it, The prop is a Tonini gt, its a 56*44 and i am only getting 2800 rpm on climb and 2900 at 140 Kts. (160 mph) Revmaster claims full power is 85 hp. @ 3200 rpm. the climb also appears to be lacking. engine is a revmaster R2300. I am missing 3-400 rpm. would trimming down the diameter a little at a time give me back my missing revs.My other thought is, the engine now only has 1.2 hrs on it from new, can the engine develop more power as it runs in, so am i jumping the gun thinking about the prop yet.Test pilot claims the 'little KR' (smurf jet) is a beautiful little plane to fly, well balanced in all controls and, the mod to the tail (same as Troy Petteway's ) has really paid off. not overly sensitive throughout the whole speed envelope and still powerful enough for full control at low speed. (big relief !!).Other thing is i may have ballsed up on my tail incidence as the nose keeps wanting to lower even with full up trim, I added a second adjustable trim to the control bell crank at the elevator with bungee cord to between the seats and that still required a lot of pull to trim the plane out. ortest pilot is also a light weight (he is), I haven't checked the weight and balance figure but I am guessing he has put the CG fwd of the fwd limit. (as a 85 kg (187 lb to you yanks) pilot and full head tank I am 1/4" aft of the fwd limit). I have been told this was to be expected on the first flight (nose down trim that is)One more thing, I have lagging on my header pipes can this cause me to have higher than expected EGT temps approx 50c and higher. (122f for the yanks), lagging was put on to protect wiring and coils, on the R2300 with individual ignition coils, the front exhausts run parallel under the head and approx 1/2" away from the coils.
KR> first flight advise
Thanks guy's for the reply, I had not even considered the thought of flying several different aircraft before mine but it is a good logical idea and i know were it is coming from as I have driven a lot of different machines over the years, from small underground loco's to giant mine face shovels and you need to approach each one differently and feel what the machine is telling you before you act. but for this purpose I am only limited to a small few planes. And by the way if any one is on the hunt for tail wheel came across this, a Tail Wheel Assembly and hardware. from fisher flying products, looks like a neat unit. --always great to find something after you have already made it!!--And thanks Mark for the offer for my link but my my web site is already there in the builders list. unless you had something else in mind, in any case it's OK, its out there for anyone to look at.
KR> first flight advise
Thanks for the first flight test plan Mark, I will be seriously studying that.here is a couple of specs on mine if it helps any one for my first flight advice and what to expect,I pretty much built mine exactly the same as Troy Petteway's. Based on photos and his tail specs.It is a standard KR2 , apart from the tail. and fixed gear (Dhiel) T.G.I increased the stab span by 6" on both sides and reduced the elevator by 4" on both sides, pretty much same as Troy's (built that way with fear in mind of pitch sensitivity in the early stages), Increase the height of the fin by 4"Wing is the AS5046.Empty weight is 635lb./288kg Mean CG, aft face of fwd spar is 54.5" from spinner back plate. CG. with full fuel (head tank and wing tanks) and 1 pilot is 971lb./440kg. CG. is 1/4" fwd of mean CG. Head tank only with 1 pilot is 894lb/405kg, CG is 1 3/4" fwd of mean CG. Engine is a 85hp Revmaster R2300 with Revflow carb and prop is a Tonini Bro. GT 57" * 44". Pilot weight based on 187lb/85kg. "i'm a little lighter than that!"if any ones interested in some pics there is some here of it http://www.lilausydreamkr2.com/general-pics.html.
KR> est. w
Hi all,I finally just completed my KR2 on the 1/NOV/2013, 2 years 3 months and 1800hrs (yipee!), and after final weigh in 4 days ago i have an mt. weight of 635lb/288kg and a gross weight of 1162lb/527kg that's with 26.5gal/100L. fuel (Aus. is a big place!) and based on two 85 kg pilots on board.I am now about to go back to sea for four weeks so I now have to sit wait to get the permit to fly in the mail, and to get the first flight out of the way and thinking of that, I had a pilot organised to do the first flight for me, he came around yesterday to do his own inspection on it and could not wait to do the first flight UNTILL he tried to fit in it! He couldn't even get his knees under the dash let alone close the canopy. He didn't look that much bigger than me! considering that I had built it around myself. Bit to be said for the size of the KR!So what tips can I get for the first flight? If I end up doing it myself.
KR> KR and pilot
My condolences to Ben's family, I only found out a few days ago, I was hoping to catch up with him during my leave home from sea this time, so I could get some time in his before I fly mine for the fist time.
KR> aileron pushrods
from my previous question regarding aileron pushrods I am searching for solid steel rivets for the aileron push rods and can't find any, I would prefer to use the steel rivets, as the rod ends and tube are chrome steel, were I think with alloy or monel rivets there will be corrosion issues over time. (indifferent metals = corrosion. as I was taught at school.) any one have any other suggestions.or another option. would steel cherry rivets be considered strong enough to do the job? in place of solid.
KR> Aileron pushrods
This is more addressed to Mark Jones (N886MJ) I am nearly ready to make the aileron push rods for my kr2.I have ordered and received the parts that you listed from an old archive message.AN490HT8P rod ends 1/2" * .035" 4130 tube and the MW-4 bearings. next question is. What rivets did you use to attach the rod ends to the 4130 tube? So many rivets to choose from!
KR> serial numbers
I have a question regarding serial numbers as I am about to start a request for the the rego numbers here in Australia and they require the serial number. I have been told that the serial number should be printed inside the front cover of the construction manual but the only number there is an EAA# 51###. (5 numbers long don't seem long enough for a serial) but is this the serial number?The manual is pretty old, last revised 1977 rand robinson. I hope this is it as I am getting close to completing the plane now and I dont really want to buy a new set of plans just for the number.
KR> tail spars
I have a question about using the tail rib templates on the existing preshaped spars for the KR2.with the stab foamed up between the spars and the tip template glued in place would it be safe to fill the gap to make up the thickness of the spar by pouring in polyurethane foam then sand down to shape, or would it be better to cap and shape the spars with some more spruce, I ask this as my spars have already been sized to the original plans with the 5/8" sq. tips and i want to use M. Langfords profiles.
KR> as5046 profile
Hi from Robert Gill in Tasmania Australia,I have just started construction on a standard kr2 project that was given to me, the boat hull is complete and the center spars have been glued in place the stab and elevators have been built but not glassed or glued to the Fuse.I have been reading Mark Langford's artical on the design of the AS5046 profile and he refers to others that have modified there kr2s with the new profile.My question is while mine is at this stage of construction can the AS5046 profile be used on the standard KR2 and use the construction methods as explained in his artical, by raising the TE spar to decrease in incidence and increasing the main spar thickness with extra capping and then the tail incidence to match, will this work? and will it work with the standard tail profile. His artical seem to only refer to the KR2s.
