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Old Jun 09, 2010, 06:43 AM
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Ashford. Kent. England
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With your Nutball the motor is usually mounted central to the wing with at least 5 degrees down and 3 right... most of mine go better with more down.. If you mount the motor high you will need less down and vice versa...Its also best to fly it on minimum power till its trimmed... and I do mean minimum, just enough to get it up..
If you build a depron version go 24" up and add a KFm2 step... if much bigger go KFm4
Ditto the Dart-xs....
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Old Jun 09, 2010, 10:12 PM
Crash Master
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Indianapolis, IN
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Originally Posted by NoFlyZone View Post
...With that said, I have settled on a plane I ran across in my searching that I'm going to give a go. Seems it has a simple airfoil, and in looking at it, I may just use Depron rather than the 9mm EPP it calls for. I should be able to get it built far lighter than the 7-8 ounces it calls for with EPP.

It's called the EPPiper, and it looks like a good way to get into this aspect of the hobby...
It should do fine with Depron. Just make the step the equivalent height, taking the foam thickness into account. (9mm + 9mm = 3mm + 3mm + 12mm)
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Old Jun 09, 2010, 10:20 PM
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It should do fine with Depron. Just make the step the equivalent height, taking the foam thickness into account. (9mm + 9mm = 3mm + 3mm + 12mm)
Thank you, Gene!
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Old Jun 10, 2010, 10:41 PM
Onward through the fog.
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I had to post this one...

I don't beleive this wing's slow handling performance....
Singer2 Ses3.wmv (3 min 36 sec)


Steve.
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Old Jun 11, 2010, 12:47 AM
just Some Useless Geek
Chicagoland
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I did a search, but can't find a discussion on the practical upper limit to airframe/wing sizes for KF airfoils. I'm building something like an Albacorde out of 1/2" purple Foamular and was thinking about a KFm4 for the wings. Length: one and a half meters. WS: one and a quarter meters. Kinda big.

Has anybody done any research along these lines? The search phunction here isn't great.
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Old Jun 11, 2010, 01:24 AM
Onward through the fog.
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Originally Posted by A Useless Geek View Post
I did a search, but can't find a discussion on the practical upper limit to airframe/wing sizes for KF airfoils. I'm building something like an Albacorde out of 1/2" purple Foamular and was thinking about a KFm4 for the wings. Length: one and a half meters. WS: one and a quarter meters. Kinda big.

Has anybody done any research along these lines? The search phunction here isn't great.
My first, PI, RC plane about a year and a half ago was Fubar. The wing was a polyhedral 72" span by 10" chord KFm2 and it flew just fine. The wing outlasted several fuselages. (3 or4) And eventually folded on the last model. No scientific data available but they seem to work fine around the 2m span level. Be sure to reinforce and brace the wing adequately.

She flew on a BP21 on 2s Lipo with a 10 x 4.7 SF prop on direct drive and it was a decent flyer on RET.

Here's an old Vimeo video.
Third Flight of Fubar (0 min 49 sec)


Dave, Didn't someone build an 8' span Zagnutz???

Steve.
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Old Jun 11, 2010, 01:58 AM
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where steps are still helping

guys: it is great that you are trying to find out the upper limits where steps are beneficial.
i have been exchanging comments with Dick about this issue.
first of all, what do you expect from steps? what are you looking for?
more stability? more cargo? faster? more flat glide?
i think that the only way to see the difference between using steps-or not-is by building 2 identical models: 1 with, and another without.
then you will see which 1 flies better (slower/faster-more stable-higher/lower rate of sink-more cargo lifting-whatever).
build 2 of the same model of 6 foot; then 2 of 7 foot, and so on.
until then, you will not see when the steps are no longer helping.
just because that plane flies fine, or seems to be flying fine, does not prove that it is doing better with steps. it may be that it is just a good design.
full scale aviation found out that they don't give them what they need, but where we have to stop?
it's up to you, adventurous minds.
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Old Jun 11, 2010, 07:32 AM
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Quote:
Originally Posted by A Useless Geek View Post
I did a search, but can't find a discussion on the practical upper limit to airframe/wing sizes for KF airfoils. I'm building something like an Albacorde out of 1/2" purple Foamular and was thinking about a KFm4 for the wings. Length: one and a half meters. WS: one and a quarter meters. Kinda big.

Has anybody done any research along these lines? The search phunction here isn't great.
Ive had a 6ft wing flying with a KFm foil, it flew fine, just the same as its smaller brothers, but with a bigger span came slower roll..Designed as a glider, it was boring...
I seem to remember some very big wings flying...

Phil
you are quite right, without direct build comparisons it is difficult to be certain that the steps improve the flight...however its the simplicity of a KF build that does it for me, every time... I can knock up a KF wing in a fraction of the time that a built up wing would take.. It will be as strong, if not stronger, and it will fly well.
The only time now, I would build up a wing, is for a scale jobby..
Would a fancy airfoil fly significantly better?...or not...and even if it was better, would I take the trouble to build it up...I doubt it, I prefer the simple and easy build..
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Old Jun 11, 2010, 08:33 AM
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Windsor, Canada, near Detroit
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fancy airfoils

you know, Dave, i like all kinds of airplanes. i have discovered foam, and steps, and i realize they go hand-in-hand: are made for each other.
stick-and-tissue is still deep in my heart, and will keep designing and building planes for that.
but with foam, building is way faster-and easier, so you are flying in no time, and enjoying it!
also, as steps make an aircraft more stable (forget about efficiency-that's beyond the point), it is possible to fly aircraft that otherwise would be unthinkable.
take your horten wing, for example. and birds. all kind of wings (flying wings). canards. you name it.
for those reasons, with foam there is a better chance that someone will eventually find out how far (in size) an aircraft can go with steps.
so, there is room for fancy airfoils, for those inclined to do so (am 1 of them), but we must admit that foam and steps, for all the advantages that they offer, will be used more and more as time goes by.
and for the tests that i suggest, perhaps the easiest way could be to build 1 aircraft without the step and flight-test it (if the structure allows for doing it-maybe too weak), then add the step(s) and fly it again, so you don't have to build 2.
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Old Jun 11, 2010, 08:34 AM
gpw
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Quote: "I can knock up a KF wing in a fraction of the time that a built up wing would take.. It will be as strong, if not stronger, and it will fly well."
That's my opinion as well !!! I don't see any size restriction on the KF airfoils... just the question of transporting LARGE models ....
Somebody needs to make a KF Hang Glider... BIG!!!
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Old Jun 11, 2010, 08:49 AM
Lee
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There is a place in the world for KF airfoils but there is also a reason they aren't on commercial planes. Remind yourself of the variety of airfoils available.

http://www.ae.illinois.edu/m-selig/a..._database.html

In the slow models that we often build they they fly well. I watch this thread because the variety fascinates me. I particularly like what Steve does because he makes up his own rules as he goes along and isn't afraid to try anything over and over till he gets it right. He is good for the hobby. For Steve and others like Steve the KF airfoil is a blessing. It gives options for design for the kitchen table builder.

I was thinking that it might be interesting to cut a clark Y airfoil and run it though my horizontal slicer and separate the top from the bottom, fly with it flat then start adding the top back in pieces first with a notch then complete to see what the difference is but I'm starting to think it doesn't matter. The KF is what it is. Most people understand that and it does adapt well to some odd planes that would be very complex to cut with a conventional airfoil. Look at the Peregrine thread if you don't know what I am talking about.

Look at the FFF Eagle linked in post #3. http://www.rcgroups.com/forums/showthread.php?t=950519

Lee
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Old Jun 11, 2010, 09:06 AM
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Valley Village, CA
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Quote:
Originally Posted by gpw View Post
Quote: "I can knock up a KF wing in a fraction of the time that a built up wing would take.. It will be as strong, if not stronger, and it will fly well."
That's my opinion as well !!! I don't see any size restriction on the KF airfoils... just the question of transporting LARGE models ....
Somebody needs to make a KF Hang Glider... BIG!!!
I believe the first test of a KF wing was a full scale glider where a portion of one wing was given a step. Dick has an article he sent, written by Dick Wood, which goes into detail about it. It was an ultra light called the Vector 600.

I can post it, but I think I would like Dick's (Kline) approval first.
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Old Jun 11, 2010, 02:38 PM
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I believe the first test of a KF wing was a full scale glider where a portion of one wing was given a step. Dick has an article he sent, written by Dick Wood, which goes into detail about it. It was an ultra light called the Vector 600.

I can post it, but I think I would like Dick's (Kline) approval first.
By all means post the article. Dick Wood of Ontario had the guts to build and fly his ultralight aircraft back in 1987. He reported that versus a conventional wing his stall speed was reduced by 10%.
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Old Jun 11, 2010, 03:23 PM
just Some Useless Geek
Chicagoland
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Okay, then. What I am hearing is that it still makes sense to build up my twin motor, delta wing, long root chord park jet with a KFm4. The step will help add rigidity to the wing, and, I am hoping, make it easier to fly as well. So be it.

Stay tuned.
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Old Jun 11, 2010, 04:58 PM
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Originally Posted by Dickeroo View Post
By all means post the article. Dick Wood of Ontario had the guts to build and fly his ultralight aircraft back in 1987. He reported that versus a conventional wing his stall speed was reduced by 10%.
Here it is.
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