Re: KR> Cockpit vacuum gauge

2017-02-02 Thread Jeff Scott via KRnet

 
 

Jeff said,

> "I don't think the manifold pressure gauge [vacuum gauge] is going to
tell you much other than your throttle setting for a given altitude."

It won't even do that if you fly wide open throttle - which if above 8K I
assume everyone does.

Steve Bennett had a chart that showed what information could be derived
from a vaccuum gauge. I just went looking for it but couldn't find it.
It's out there on the internet - behavior of the needle indicating
various possible engine problems. Steve once recommended I put one in so
I did . . . but I've never found the gauge useful at all. The way I fly,
unless I've just taken off and am climbing, it always reads zero.

Mike
KSEE
---

Actually, a manifold pressure gauge will show absolute pressure, which changes 
with altitude even at full throttle. (30 in manifold pressure at sea level vs 
20 in manifold pressure at 10,000').  That allows you to calculate percent 
power.  FWIW, I am almost always flying above 8000' since the airport is at 
7200', but I rarely cruise at full throttle.

I suspect the initial question was asked based on the vacuum gauge 
interpretations on this web site: 
.  First off, the 
interpretations on that web site are pretty lose interpretations.  Secondly, 
the things they are interpreting via a vacuum gauge would be detected much 
earlier during any type of regular engine maintenance (differential compression 
test, mag drop test on run-up, and mag timing check).  The third point is that 
a manifold pressure gauge is usually installed with a restricted port, and a 
fairly long 1/8" copper line, so any of the vacuum interpretations from that 
web site would be pretty well buffered out of the manifold pressure gauge 
readings.  That is by design in order to prevent having a significant vacuum 
leak into the intake manifold should the line to the manifold pressure gauge 
fail.

-Jeff Scott
Los Alamos, NM

 

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Re: KR> cockpit vacuum gauge

2017-01-31 Thread Jeff Scott via KRnet

 
I have a manifold pressure gauge in my KR. It's nice for fine tuning throttle 
settings and calculating percent power, but it's only there as a personal 
preference and is completely unnecessary without a constant speed prop.  Can't 
say that I would be able to diagnose valve issues or engine health with it.  I 
find EGTs and a static compression differential test to be a much better 
indicator of what's going on with the engine.  

1 EGT running 50 - 100° higher than normal is an indication that a spark plug 
is not firing.  All EGTs running 50-100° higher than normal is an indication 
that a mag may have failed.  Just pulling the engine through as part of your 
preflight should indicate if you have a valve or cylinder issue as you'll feel 
the soft cylinder and will hear it leaking.  I've seen a lot of different 
failures in aircraft engines, but short of launching a cylinder off the case, I 
don't think the manifold pressure gauge [vacuum gauge] is going to tell you 
much other than your throttle setting for a given altitude.

-Jeff Scott
Los Alamos, NM


--
Subject: KR> cockpit vacuum gauge
Anyone running a vacuum gauge in their panel. Is it not an indicator of engine 
health, valves etc

Craig


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Re: KR> DAR inspections

2017-01-22 Thread Jeff Scott via KRnet

Bob,

In the US, a DAR inspection is the only FAA inspection required on an Amateur 
Built Aircraft, and is only performed after the aircraft is completed.  All 
other inspections are typically by an EAA Tech Counselor and are strictly 
voluntary... i.e. not required.  Even the Tech Counselor inspections are only 
recommended 3 or 4 times during construction.  It is highly unlikely that the 
Canadian Government would be willing to backtrack and allow you to use what 
they would consider to be uninspected parts such as the box spars, closed out 
wings, or a closed out fuselage.  

-Jeff Scott

-
Hi All;
I am considering a project in the U.S. that has no documentation whatsoever and 
am wondering about DAR inspections.
I want to import this project into Canada and our inspections require a pre 
cover (before box spars etc,are closed in) .
What I am wondering is if I might find a number or something that shows it was 
done in the U.S .
In Canada each component is stamped or stickered to show it has been done.
The project is fairly complete all spars are closed, wings closed etc.although 
it would still meet 51% requirement here in Canada.
I f I can show the inspections I an import as parts and then continue it.
Any thoughts about this?
Thanks
Bob R
Winnipeg
Canada

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Re: KR> Tailwheel assembly

2017-01-22 Thread Jeff Scott via KRnet


You can order direct or through your favorite aircraft parts vendor. If your 
spring is mounted at a non-standard angle, they will be happy to make one to 
fit your plane.  Choose between the 4" solid tail wheel or the 6" 
semi-pneumatic tailwheel (hollow inside to make a bit softer).



-Jeff Scott
Los Alamos, NM
 
---
I have a glass round tailwheel spring from Stev glover where do I get the 
tailwheel assembled to fit that spring. I have s new Matco unit but it seem 
very heavy
Phil Matheson


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Re: KR> Archives

2017-01-25 Thread Jeff Scott via KRnet

 
Ron,

That's the way it's supposed to work... in theory.  The reality is that many 
FSDOs simply don't have the manpower to do amateur built inspections.  I have 
seen guys get held up for a year waiting on FSDO to do an inspection because 
they wouldn't cough up the $500+ travel expenses to pay a DAR.  It varies 
widely from region to region and from time to time. DARs are contractors and 
charge what they think is reasonable for their services.  Some are $200.  Some 
are $1000.  Some do good inspections.  Some will drive up in their motorhome 
with the boat on behind, sign the paperwork on the way by while heading for the 
lake and charge you travel time for it on top of their fees.  It's a real crap 
shoot.  However, it is a much better system than what we had prior to the rule 
changes in 1980.

-Jeff Scott
Los Alamos, NM

-
Why do you even need a DAR during the build?  3 visits, for what?  The FSDO in 
your city will come out for free if you can ahead and get on their schedule for 
a final inspection, which is all that is required (unless the rules have 
changed)??.
RonSt. Louis, MO



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Re: KR> Melting lead

2017-01-27 Thread Jeff Scott via KRnet
Or you might want to consider using lead shot mixed with epoxy resin and either 
flox or milled fibers.  Makes it easy to mold to shape cold.  Lead is a 
distinctly unhealthy material to be melting. 

-Jeff Scott
Los Alamos, NM
 

Subject: KR> Melting lead
First a comment before my question.  In the book it says to use an old pot to 
melt lead down for the aileron counter weight.  I'll give you some advise. What 
you consider an old pot is might be different then what your wife considers an 
old pot is. Be forewarned

How do you melt a 5 lbs chunk of lead on the stove? I did an internet search.  
Lead melts at 621 degrees.  I'm not even getting close to that.


Paul Visk 

Belleville Il.

618-406-4705

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Re: KR> Aileron hinge bolts

2017-01-20 Thread Jeff Scott via KRnet
Either method works just fine.  I chose to counterbore the hinges and used 
flush screws with the screws offset between the aileron and the wing.   Like 
Larry, I also floxed a set of #8 nut plates to the back of the mount holes to 
make them removable.  

One note on self locking nut plates like what are used in this application.  
The pinch on the end of the nut plates as manufactured is a bit too tight.  
Most savvy A will run a tap through the nut plate.  They will still be self 
locking in that the screws will not loosen up, but they won't destroy Stainless 
screws, and the nut plates won't twist out of the floxed mount if you ever have 
to remove the aileron.

-Jeff Scott
Los Alamos, NM

---
I'll be ordering my aileron hardware from Wicks soon. In looking in the book at 
10.59. It says to use 8/32 pan head bolts for the aileron hinge. Has anyone had 
problems with sufficient clearance between the heads of the bolts if they're 
lined up with each other?  Or should they be offset. I believe I've seen some 
people use countersunk bolts. Any advice would be appreciated. 


Paul Visk Belleville Il.
618-406-4705

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Re: KR> Aileron hinge bolts

2017-01-20 Thread Jeff Scott via KRnet
Unsanctioned by USAF?  Yes.  We only did that when the inspectors weren't 
looking. :o)  

For others, running a tap through the metal self locking nut plates does not 
destroy their self locking qualities.  They don't just bind as tight, so they 
don't destroy the threads on Stainless screws or bind the steel screws so tight 
that the heads strip.  But they do still bind well enough to meet the specs for 
a self locking nut.

-Jeff Scott

--
Subject: Re: KR> Aileron hinge bolts
Thanks for the advice guys. Jeff, I thought that was an unique Air Force  
unsanctioned trick that we used to do years ago. : )

Paul Visk Belleville Il.
618-406-4705

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Re: KR> Aileron hinge bolts and BID

2017-01-20 Thread Jeff Scott via KRnet
Just notch a step into the skin large enough for the false spar to sit in the 
skin, then scrub the foam out from between the layers about 1/4" deep.  Fill 
with Flox and slide the false spar into place.  Your call whether you want to 
add a layer of glass to it while the flox is wet or not.  I had the nutplates 
already floxed onto the inside of the false spars when I installed them.  When 
I glassed over them, I had a set of screws that I had dipped in floor wax to 
screw through the wet glass into the nut plates to keep the holes clear.  Once 
cured, they easily unscrewed.  No need for a vacuum bag. 

It hasn't been mentioned in a while, but there have been some failures of the 
aluminum L bracket that the Aileron counterweight mounts on.  Some folks have 
replaced theirs with 4130 L brackets.  I still have the aluminum brackets on my 
KR after 20 years and 1150 hrs, but if I was building them today, I would use 
4130 for the brackets.

-Jeff Scott
Los Alamos, NM
 

Hi all,

On this note, I did the 8/32 pan head off-set; results to follow the next
installation:

The next steps for the aileron attachment in the plans call for Flox the
attachment nut, add the counter weight arm (middle), then 1 layer BID
overlapping at least 1 inch.

I've been stewing about this for a few weeks. I have wings built with
Diehl skins raf48.

It seems to me that I should flox or epoxy the 1/4" spar to the wing and
to the aileron prior to BID. Did anyone do this?

Then apply BID to further secure the aileron. Do I need to use a vacuum
bag? Or can I use just gravity and hand placement (assuming I can square
the spar with clamps)?

Any feedback on process and results would be great!

Thanks,
Tucker

Denver, CO


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Re: KR> Melting lead

2017-01-28 Thread Jeff Scott via KRnet
You are allowed to expose yourself to lead if you choose.  I think most of us 
have, including me on numerous occasions.  But after watching a friend's 
illness with lead poisoning from bead blasting aircraft cylinders IN a bead 
blasting cabinet, I don't work with lead anymore without adequate precautions.  
I would suggest you describe your operation to an Industrial Hygienist and ask 
for an opinion.  You might be surprised at what they say.

I can tell you from work that I am required to take about the same precautions 
when casting, melting or forming Lead as when doing equivalent work with 
Uranium.  Once you get a dose of lead poisoning, you end up doing Chelation 
Therapy for years to reduce the amount of the heavy metals in your system and 
get your head on straight again.  The point of the post isn't that you can't 
melt lead and get away with it.  The point is that lead is highly toxic and 
there are other ways to form your counterweights without exposing yourself to 
the potential of lead poisoning.  Lead poisoning sneaks up on you first as 
memory loss or lack of ability to concentrate.  It can be confused with 
symptoms of aging, so Drs don't typically test for lead poisoning unless you 
tell them you have had exposure.  Chelation therapy can help you to slowly 
recover.  But it's best not to put yourself into the position to need it.

If one feels that they must melt lead, try to do so with good ventilation and 
take precautions to minimize exposure.  What was an acceptable practice in the 
plans from 45 years ago has been demonstrated to be unnecessary, highly toxic, 
and a risk to your health.  So why do so if you don't need to?  

-Jeff Scott
Los Alamos, NM



--- 
Subject: Re: KR> Melting lead

I have melted lead many times on the stove and I think all my brain cells
remain intact. You're melting it, not boiling it, so the amount getting
into the air is insignificant. Obviously don't ever use the pot again for
food. A tin can sounds like a good idea.

Mike Taglieri




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Re: KR> Fuel header tank

2017-01-16 Thread Jeff Scott via KRnet

 
 
Like Joe, I also have a small composite header tank and wing tanks.  I carry 9 
gallons in the header and 6 1/2 in either wing.  I run gravity feed from the 
header at all times, and transfer fuel from the wings to the header 
periodically in flight.  With this type of configuration, I see very little CG 
shift on any given flight.  Some people don't like having fuel in the cockpit.  
Some of us don't mind having header tanks.  That's your call for your own 
safety.  Not having a header tank in the way makes maintenance behind the panel 
easier.  Ultimately, it's your call.

-Jeff Scott
Los Alamos, NM


-

Subject: Re: KR> Fuel header tank
Hi Deon,
I have a KR-2s with a 12 gal. header tank and am currently building another 
that I retained the same idea but in a slightly smaller form of 7.5 gal. My 
theory is that gravity never quits so fuel flow would never quit. Having said 
that the KR2 is much more pitch sensitive. During any cross country flight I 
probably only adjust trim one time as the fuel is burned off the header tank 
and it is really not an issue for the 2s stability. The other main issue is 
safety which is up to any one persons own tolerance. I personally have a 
fiberglass header tank and the plan is not to break it. That is not good enough 
for many good men. You have an aluminum tank which may or may not be stronger 
and less resistant to a rupture. Another down side to wing only is the fuel 
line and pump layout and operations.
    Having mentioned all these items I would likely put in wing tanks and ditch 
the header. I do not know what stag of completion the plane is in but maybe 
adding to the fuselage length is an option. It would be a far safer airplane by 
all accounts.
Joe Horotn,
N357cj
 

- Original Message -

Subject: KR> Fuel header tank

Hi Guys

The partial KR2 (original design) I have bought is fitted with an
aluminum fuel tank in front of the instrument panel. From the
information I have available this is not a good idea (shift of CoG, fire
danger etc.)

Would you advise that I ditch this and create wing tanks? Given all the
ho-ha about CoG issues I am not sure I will be able to pass inspection
with this tank in place!

This is a big step for me so some advice would be appreciated.

Regards

Deon


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Re: KR> engine update

2017-01-17 Thread Jeff Scott via KRnet

 
 Clearly you took good notes when you visited my shop!  -Jeff Scott

---
Cc: "Oscar Zuniga" 
Subject: KR> engine update
Larry: I see your problem immediately. Your hangar is too clean for you to get 
any serious work done. I do not see *any* tools on the floor, *no* old gasket 
scraps, dripped oil, pieces of snipped safety wire, errant washers, used and 
bent cotter pins, or any other evidence of actual progress on your engine 
removal and overhaul. I do not see any masking tape with handwritten labels on 
any wires or cables on the firewall, no yellow note-pad with items to remember 
to take care of in reverse order when re-assembling, so it's obvious that 
you'll never get everything put back in the proper place even if you get the 
engine overhauled in the first place. Which is questionable, since the short 
block is not sitting on an old blanket, some old sofa pillows, or a worn-out 
6.00x6 tire. These things are necessary for a proper engine rebuild, so you 
might want to get busy and get your hangar in order.


You need to take a serious look at getting your hangar disorganized so you can 
make measurable progress. And PS, a light coating of spilled Aeroshell 50 with 
about 20 hours on it will help cut the glare from the overhead lights off that 
clean floor. Just sayin'.


Oscar Zuniga

Medford, OR

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KR> Most heavy engine

2014-05-08 Thread Jeff Scott via KRnet
I am a bit confused about the 160 HP Continental engine. ?What engine model is 
that? ?Continental made an O-346 which is 165 HP, and an O-300, which is 145 
HP. ?Or do you mean a 160 HP O-320 Lycoming? ?

George McHenry had just replaced the O-235 Lycoming on his Single Seat KR-2S 
with a 160 HP+ O-320. ?He had gone out of his way to keep the engine as light 
as possible. ?Unfortunately, he was killed on his first or second flight behind 
that engine. ?Cuase of the crash is still unknown, but you can look up the 
write up on the NTSB reports, Pueblo, CO, Sept of 2012.

Even with his hopped up O-235 (roughly 140 HP), he was able to go run with the 
RV crowd. ?He loved to put on O2 and cruise at 17,500' when headed east with 
the winds. ?So even an O-235 is more than enough HP as you have to be very 
careful about VNE and flutter. ?I know George got himself in trouble with 
flutter on the rudder at one point in time and broke one of the two rudder 
hinges in flight.

Even with the O-200 on my KR, when I am at altitudes below 5000', I have to be 
very aware of my speed as it is quite easy to blast past the 195 mph IAS VNE 
just doing a slow 300 fpm descent.

One thing for sure, depending on what engine you just traded for, you could 
easily swap it for a Lyc O-235 or Cont O-200 and have a plane with fabulous 
performance. ?With 160 HP, you're going to need bigger fuel tanks for the same 
range, which makes for more weight on top of the heavy engine. ?There are a lot 
of trade offs to consider.

-Jeff Scott
Los Alamos, NM




> - Original Message -
> From: Hennie van Rooyen \[HQP Alloystream\] via KRnet
> Sent: 05/08/14 07:37 AM
> To: KRnet
> Subject: KR> Most heavy engine
> 
> Hi everyone,
> 
> Don't crucify me, this is only a question. I am able to lay my hands on a 
> good 160hp Continental engine, complete with prop & running. What is the 
> heaviest & most powerful engine ever put in a KR2? I see it weighs 297 lbs 
> compared to the 227 of the Corvair.
> 
> I say again, this is merely a question out of interest. Please don't attack 
> me.
> 
> Keep well all,
> 
> Henni
> This e-mail is confidential and is for the addressee only. 
> Please refer to http://www.exxaro.com/content/main/disclaimer.asp
> for important disclaimers.



KR> FW: Bob Lee's passing

2014-05-10 Thread Jeff Scott via KRnet
Mark,

Thanks for passing this along. ?I knew Bob was in the end game from your last 
post about him a few weeks ago. ?He was one of the good guys and will be sorely 
missed. ?I'm relieved that he was able to pass on without lengthy suffering.

Jeff Scott
Los Alamos, NM

I noted that KRGathering.org no longer responds on the web, so it must have 
expired.



> - Original Message -
> From: Mark Langford via KRnet
> Sent: 05/09/14 07:43 AM
> To: KRnet
> Subject: KR> FW: Bob Lee's passing
> 
> Many of us got to know Bob through the Gatherings. He was always there
> carrying on conversations, exchanging ideas, and helping where he could.
> See below... 
> 
> From: Cheryl Lee [ shortbus1017 at gmail.com ] 
> Sent: Friday, May 09, 2014 8:07 AM
> To: 'Mark Langford'
> Subject: Bob
> 
> It is with a very saddened heart to let you know that Bob passed away last
> night in his sleep. We got news about his cancer on Tuesday and Bob got
> very lucid and made his wishes known. We came home from the cancer center
> on Wednesday and had a family meeting with the kids. He let the kids know
> he loved them very much and what his wishes were. We had family portraits
> taken yesterday afternoon at 4:00pm. We had a hospice nurse scheduled to
> come to the house as Bob had started having pain earlier in the day. After
> the pictures his pain increased so I made arrangements to have him go into a
> hospice facility. We took him around 6:00pm and they got him very
> comfortable. We left the facility around 9:30pm and at 1:00am this morning
> I got a call that he had passed on. The kids and I went back and was with
> him for a couple of hours before the funeral home came to pick him up. We
> will be working with the funeral home on arrangements today and will let you
> know. Please let the KRNet and other website know about Bob's passing.
> 
> Thank you for your help.
> God Bless You,
> Cheryl



KR> Fw: Re: Propellers

2014-05-10 Thread Jeff Scott via KRnet
After a fair amount of experimenting with props over the years, I will 
respectfully disagree with you, Jeff, and agree with Tommy. ?But I will also 
state that the statement about longer props equals better climb is only true 
within limits until you reach a point where the engine HP gets used up by the 
tip drag as I'll discuss further down in this post. ?

One specific instance that comes to mind was a propeller I had on my KR for a 
number of years from Performance Propellers. ?It performed reasonably well, but 
after checking and finding that my Tach was reading 200 rpm high, I knew that 
with a bit less pitch, I should be able to turn the engine up another 200 rpm 
improving both climb and cruise performance. ?I pulled the prop off and sent it 
back to the manufacturer to be repitched to a lower pitch to allow it to turn 
another 200 rpm. ?When I got the prop back and flew it, I knew without even 
measuring it that he had cut the tips off the prop rather than repitching it. 
?It took a lot more RPM to do anything, but the takeoff and climb performance 
was seriously off. ?When I called the manufacturer, he confirmed that he 
decided to be lazy and cut 2" of diameter off the prop rather than repitching 
it as I had requested (and paid) him to do. ?For use on my plane, the prop was 
essentially ruined.

On an Avid Flyer that I built using a VW engine, I simply could not get it to 
perform at our 7000' elevation here in Los Alamos. ?I returned the prop to Ed 
Sterba for some adjustment to the pitch. ?When I got it back, it really didn't 
perform any differently, nor did the engine turn up any better. ?I called Ed 
and discussed the issue with him and we formulated a plan. ?The issue was that 
the prop was simply too long for the engine as the tip drag was using up all 
the horsepower rather than generating thrust. ?I took a ruler and marked the 
prop tips in 1/8" increments. ?I would take the plane out for a test ride, then 
come back and saw 1/8" off both prop tips, reducing the diameter of the prop by 
1/4" increments. ?With each pass, the engine turned up more, with some gain in 
performace through about 3 or 4 iterations. ?The next iteration I saw more rpm, 
but no change in performance. ?Then the next iteration the engine again gained 
rpm, but the take off and climb performace was showing a definite decrease. ?I 
would have loved to have continued cutting on the prop to see how much more it 
would drop off, but since I couldn't add back onto the prop, decided to stop 
there.

I also built and fly a SuperCub. ?It's pretty common knowledge and has been 
demonstrated over and over that if you want a 160 HP SuperCub to get off the 
ground short, you take off the stock 74 x 58 McCauley prop and install an 84 x 
43 McCauley prop. ?The rpms are about the same, but the plane will get off the 
ground much quicker (roughly half the distance!) and climb significantly 
better. ?It's pretty obvious that the longer prop pulls better. ?The thrust 
difference is quantifyable by pulling static against a scale. ?A number of the 
SuperCub guys have done just that to prove it out. ?Craig Catto is in the 
process of develping an STC to use his long 82 - 84" props on certificated 
SuperCubs. ?However, everything with a prop is a compromise. ?To get that super 
take off and climb performance out of a SuperCub, the tip drag is high enough 
at cruise speeds that the SuperCubs lose roughly 10 mph off the top end of 
their cruise. ?Why not go to a 93" prop? ?The tip speed is high enough that the 
tips are creating so much drag that all of the HP gets used up just driving the 
tips around in a circle, so the thrust drops off. ?

>From Valley Engineering (Culver Props): ?The efficiency of a propeller is 
>reduced as the tip speed approaches the speed of sound. ?Beyond 80% of the 
>speed of sound, further increases in RPM has little effect on thrust. ?Thus, 
>it is important to keep tip speeds below 75%-80% of Mach.

Bottom line, you tune your prop for the performace you want. ?Everything on a 
prop is a compromise. ?Within reasonable limits a lower pitch, longer prop will 
provide more thrust for initial take off and climb.

-Jeff Scott
Los Alamos, NM 


> - Original Message -
> From: schmleff . via KRnet
> Sent: 05/09/14 11:39 AM
> To: tommy waymack, KRnet
> Subject: Re: KR> Fw: Re: Propellers
> 
> Not to start an argument, but I have to disagree ; )
> 
> How a prop works on a particular airplane is based on the amount of
> air moved (past the cowl, not smashing into it) and the velocity of
> that air. I have never been able to find a real reference to the
> ?large diameter prop=better climb? theory nor have I seen it work in
> real life.
> 
> On Pete?s KR, the Cloudcars 52x54 out climbs the 56x52 Sterba. Lots of
> factors there, but to sum up, the smaller diameter allows the engine
> to spin up more and make more power. The increased pitch makes up for
> the lesser disk area.
> 
> On my SI, 

KR> Drag????

2014-05-10 Thread Jeff Scott via KRnet
> - Original Message -
> 
> Maybe I AM blowing smoke and will inhale it later but I AM curious about
> all the talk of adding drag to the KR to slow it down.
> ?I have flown several low drag / clean aircraft without flaps and
> never had any unnerving problems with landing.
> ?My personal opinion banded on some experience is to fly the airplane
> as intended. Get comfortable with the SLOWER SPEEDS and then determine what
> / if anything else one needs or wants to add. THERE IS NO FREE LUNCH IN
> AERODYNAMICS.
> ?All aircraft have speeds that work best as they are intended. Whether
> a larger engine or a set of drag inducing flaps or belly board one MUST
> ALWAYS REALIZE THE CHANGE will affect something else.
> ?Doran
> ?N186RC
> ?kr2owner at email.co.

I was thinking the same way when I built my KR. ?I flew it 500 hrs with no 
flaps, belly board, or any other deployable drag. ?What I found over the years 
is that as I kept improving the plane with incremental drag reductions, the 
plane was getting more difficult to land. ?I was spending too much time over 
the runway transitioning from flying to rolling. ?At 500 hours, I did some 
major renovations to the plane  to include a 
significantly larger tail and the addition of flaps. ?To me, it was shocking as 
to how much easier this plane is to land with some kind of deployable drag. ?I 
have put another 500 hours on the plane since I added the flaps and have 
continued with my drag reduction improvements. ?It is really rare that I ever 
land this plane without flaps now that they are on there.

I don't think there was much question that I could fly the plane well in it's 
original configuration. ?(OK, some of you may think I suck as a pilot :o) ?What 
I discovered after adding flaps and a larger tail is that the plane was much 
easier to land. ?By making it easier to land, I found that I was much more 
comfortable landing the plane in more challenging wind conditions. ?Since I 
could land under more challenging conditions, I was flying the plane a lot more 
and was very comfortable flying off to other places without having to worry 
about changing wind conditions at my destination airport or the often times 
challenging wind conditions getting back into my one way in, one way out, 7000' 
high on a mesa home airport. ?Adding flaps and a larger tail to my plane simply 
made my plane so I could use it a more.

-Jeff Scott
Los Alamos, NM



KR> Fw: Re: Propellers

2014-05-10 Thread Jeff Scott via KRnet
Jeff L.

Yes, I think we are dancing around the same elephant. ?When I say I respectfuly 
disagree, I mean exactly that as I know you are really into aircraft 
performance and measurement with a lot of first hand knowledge. ?I have a lot 
of respect for your work.

My only point was that as a general statement, a longer prop will usually 
contribute significantly to both take off and initial climb. ?As you stated, 
aircraft drag becomes the more predominant factor with speed as more drag is 
generated with more speed. ?Prop length becomes much less of a factor in a 
small slick aircraft, especially at speed. ?In fact, for high cruise 
performance, too long of a prop becomes a real detriment. ?But, if you 
calculate your prop tip speed and find that it is running down in the .6 - .7 
mach area, you can usually improve your take off, climb and cruise performance 
with a bit longer of a prop. ?If your prop tips are making close to .7 mach 
static, a longer prop is likely to help with take off and initial climb, but 
may hinder cruise. ?If you're making .8 mach or more with your prop tips at 
cruise, then chances are you'll probably increase your speed by going to a 
shorter prop. ?When calculating the mach number of the prop tip, you have to 
factor the aircraft speed into the calculation. ?.75 mach static may be over .8 
mach at high cruise. ?For prop tuning, a faster plane may require a slightly 
shorter prop.

Wish I could tell you the measurements from the prop I had on the VW powered 
Avid Flyer, but that's been 15 years ago and all that information was long ago 
lost. ?Additionally, since this was all done at over 7000' altitude, the 
numbers probably would not be useful for near to sea level operations.

-Jeff Scott
Los Alamos, NM

> - Original Message -
> From: JL
> Sent: 05/09/14 11:12 PM
> To: Jeff Scott, KRnet
> Subject: Re: KR> Fw: Re: Propellers
> 
> Jeff,
> 
> Since I don't disagree with almost everything you posted, I suspect we are 
> commenting about the same elephant, but from different ends ; )
> 
> Sounds like you found the minimum diameter prop for your airplane. May I ask 
> what that prop was and at what rpm you saw no further gains?
> 
> The only thing I would not agree with is the lumping of static thrust, 
> takeoff roll and rate of climb together. I tend to view them as three 
> separate phases of flight. I think that there are certainly relationships 
> there, but just because a plane has a short takeoff distance does not make it 
> a good climbing airplane. Climb is a function of excess thrust and lift, 
> where takeoff distance is less influenced by airframe drag and more 
> influenced by raw mass flow past the cowl and anything else directly behind 
> it. 
> 
> That being said, your comment about finding the right compromise is spot on. 
> Same elephant ; )
> 
> Jeff
> 
> Sent from my iPhone
> 
> > On May 9, 2014, at 9:53 PM, Jeff Scott via KRnet  
> > wrote:
> > 
> > After a fair amount of experimenting with props over the years, I will 
> > respectfully disagree with you, Jeff, and agree with Tommy. But I will also 
> > state that the statement about longer props equals better climb is only 
> > true within limits until you reach a point where the engine HP gets used up 
> > by the tip drag as I'll discuss further down in this post. 
> > 
> > One specific instance that comes to mind was a propeller I had on my KR for 
> > a number of years from Performance Propellers. It performed reasonably 
> > well, but after checking and finding that my Tach was reading 200 rpm high, 
> > I knew that with a bit less pitch, I should be able to turn the engine up 
> > another 200 rpm improving both climb and cruise performance. I pulled the 
> > prop off and sent it back to the manufacturer to be repitched to a lower 
> > pitch to allow it to turn another 200 rpm. When I got the prop back and 
> > flew it, I knew without even measuring it that he had cut the tips off the 
> > prop rather than repitching it. It took a lot more RPM to do anything, but 
> > the takeoff and climb performance was seriously off. When I called the 
> > manufacturer, he confirmed that he decided to be lazy and cut 2" of 
> > diameter off the prop rather than repitching it as I had requested (and 
> > paid) him to do. For use on my plane, the prop was essentially ruined.
> > 
> > On an Avid Flyer that I built using a VW engine, I simply could not get it 
> > to perform at our 7000' elevation here in Los Alamos. I returned the prop 
> > to Ed Sterba for some adjustment to the pitch. When I got it back, it 
> > really didn't perform any differently, nor did the engine turn up any 
> > better. I called Ed and discussed the issue with him and we f

KR> Drag diatribe

2014-05-11 Thread Jeff Scott via KRnet
Since you made it a point to send your diatribe a second time directly to me, I 
assume the intent was to direct the same garbage at me. ?Boy, speaking of drama 
and overreactions?

I believe everything I wrote below was done in a civil, respectful manner, even 
to the point of agreeing that I once felt the same, then explained why I my 
thinking had changed. ?I won't be offended if he ignores my advice. ?Lots of 
people do. ?If you do not wish to benefit from my experience of 40 years of 
flying and building planes and over 1000 hours my KR based at one of the most 
challenging airports in the country, then feel free to skip my posts. ?If you 
don't like what the most experienced KR builders and pilots in existance have 
to say, I would suggest that you may be on the wrong forum. ?

-Jeff Scott
Los Alamos, NM


> - Original Message -
> From: Carl Dow
> Sent: 05/11/14 02:14 AM
> To: Jeff Scott, KRnet
> Subject: Re: KR> Drag
> 
> Today at 3:10 AM 
> The egos, the drama, the over reactions, the perfectionism, 
> WOW I am sick, 
> 
> Sincerely,
> Carl Edward Dow
> On Friday, May 9, 2014 10:25 PM, Jeff Scott via KRnet  list.krnet.org> wrote:
> ?
> > - Original Message -

> 
> I was thinking the same way when I built my KR. ?I flew it 500 hrs with no 
> flaps, belly board, or any other deployable drag. ?What I found over the 
> years is that as I kept improving the plane with incremental drag reductions, 
> the plane was getting more difficult to land. ?I was spending too much time 
> over the runway transitioning from flying to rolling. ?At 500 hours, I did 
> some major renovations to the plane <http://jeffsplanes.com/> to include a 
> significantly larger tail and the addition of flaps. ?To me, it was shocking 
> as to how much easier this plane is to land with some kind of deployable 
> drag. ?I have put another 500 hours on the plane since I added the flaps and 
> have continued with my drag reduction improvements. ?It is really rare that I 
> ever land this plane without flaps now that they are on there.
> 
> I don't think there was much question that I could fly the plane well in it's 
> original configuration. ?(OK, some of you may think I suck as a pilot :o) 
> ?What I discovered after adding flaps and a larger tail is that the plane was 
> much easier to land. ?By making it easier to land, I found that I was much 
> more comfortable landing the plane in more challenging wind conditions. 
> ?Since I could land under more challenging conditions, I was flying the plane 
> a lot more and was very comfortable flying off to other places without having 
> to worry about changing wind conditions at my destination airport or the 
> often times challenging wind conditions getting back into my one way in, one 
> way out, 7000' high on a mesa home airport. ?Adding flaps and a larger tail 
> to my plane simply made my plane so I could use it a more.
> 
> -Jeff Scott
> Los Alamos, NM



KR> New email program.

2014-05-20 Thread Jeff Scott via KRnet


KR> KRElevator weights advise

2014-05-21 Thread Jeff Scott via KRnet
Static balancing controls is always a safe addition to the plane, but is still 
an addition of weight.  

It's probably worth noting that the plans do not call for static balancing the 
elevator.  I have flight tested the original design elevator to 225 mph IAS 
with no indication that it might flutter.  I have the newer designed stab and 
elevator on my plane now and have flight tested it to 215 mph IAS and 225 TAS, 
also with no indication of a desire to flutter.  Both tails have been flown 
well in excess of the designed VNE.  As far as I know, there has never been an 
incident of flutter in the elevator of a KR with either tail design.  I should 
probably note that I have pushrod controls from the stick to the elevator, so 
there is no slack in the elevator control.

I was going to add counterbalances to my elevator when I built the new tail on 
my KR, but just couldn't bring myself to add more weight to the plane, so 
didn't.  I'm not going to criticize anyone for adding a counterbalance to the 
elevator, but realize that it's there to make you feel good as flight testing 
has never shown a need for it on the KR.

-Jeff Scott
Los Alamos, NM



>
> At 09:34 AM 5/21/2014, you wrote:
> >What is the objective, to center the elevator with no stick input?
> >Larry Bell
> 
> 
> The objective of balancing any control surface is to eliminate 
> flutter, not to "center" a control surface.
> 
> Larry Flesner 



KR> How do you test a transponder?

2014-06-04 Thread Jeff Scott via KRnet
The Mode C veil is not going to go away. Instead, in 2020 you will have an 
additional requirement of either a Mode-S transponder with extended squitter 
and GPS position reporting encoded into the extended squitter (known as 
1090-ES) to replace your Mode-C transponder, or you can have ADS-B Out (978 
UAT) in addition to your Mode-C transponder. You get to pick your poison.

Note: this 2020 requirement only applies with few exceptions to the same areas 
where Mode-C is currently required if you have an electric system equipped 
aircraft.

FWIW, I currently use a Mode-C transponder and ADS-B weather services (FIS-B) 
along with PCAS for traffic avoidance. By the end of this year, I plan to have 
my KR fully equipped with ADS-B traffic in (TIS-B in) and out (TIS-B out) along 
with ADS-B weather (FIS-B), all through my GPS with a 978 UAT to go along with 
my old Mode-C transponder. If you fly around traffic very much, you'll find 
these services to be quite handy.

-Jeff Scott
Los Alamos, NM



Re: KR> Pitch sensitivity

2017-01-12 Thread Jeff Scott via KRnet
What Chris describes is not at all unusual.  A number of aircraft fly better in 
an aft CG as the elevator gets too heavy with a forward CG.  A C-182 is a good 
example.  A 200 horse Muskateer is another.  It flies better and is easier to 
land if your CG is a bit aft simply because the elevator gets so heavy during 
landing when the CG is forward even though both configurations are still within 
the acceptable CG range.  Flying with a forward CG in these planes requires so 
much aft trim that the down force on the tail and trim drag is enough that the 
plane flies slower in a forward CG. 

The stock KR has so little stabilizer that an aft CG configuration can get very 
pitchy.  I flew my KR with the small tail for 500 hours before cutting it off 
and building a larger tail.  I've flown it another 650 hours since with the 
larger tail, so I think I can comment on this from a position of first hand 
experience.  After building a larger horizontal stabilizer and elevator, I 
really don't notice much difference in handling between a forward and aft CG in 
my KR as long as I stay within the 6" CG range as recommended by most builders.

I built the new stab and elevator to an 8' span using the templates Mark 
provides on his web site.

-Jeff Scott
Los Alamos, NM

 
---
 
> Could you go into further detail about "how" it flew better with a forward
> CG than an aft CG?

Sure, the plane under normal conditions (no baggage) would require
significant up trim to unload the stick, and when pulling power, would
drop the nose unless you held onto the stick. "Lawn dart"is a
description used more than once.

Conversely, with plenty of stuff in the baggage compartment (at or
near aft CG limit), the plane seemed to "float" in balance and handled
much better and was faster to boot. A pure dream to fly.

This was discussed often. It was considered by some to be good
practice to ignore the front half of the CG envelope.

It is possible that the CG envelope was shifted a bit forward than it
should have been and in fact I spoke with someone in good authority
that the aft limit was quite conservative and flying AT the published
aft limit would in fact produce good results, and it did.



> See http://www.n56ml.com/wb/index.html for more on the KR aft CG, which I'm
> pretty sure is common to most aircraft. This story should scare you...it
> certainly scared me!

I actually had read that last year, another well written piece and in
fact I am sure I saved it to PDF as well in my KR own knowlege base.


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