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Old Jun 11, 2010, 06:37 PM
gpw
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Geek , Correctamundo !!!! Works GREAT on PJs !!!!

Thanks Tolla' , just more excellent confirmation of what we know to be true !!! ...
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Old Jun 12, 2010, 03:56 AM
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Whist the KF might not be suitable for the big commercial planes Ive got a gut feeling that for normal prop private and light aircraft that a KFm2 or 4 would work, providing a much safer wing..yes the wing will stall, but at a much reduced speed, I can have my wing parachuting down with the plane stable and recover by just adding power, that stability it provides surely would be beneficial to a light aircraft, providing the advantage does in fact transfer to the full size..we all know how well it does on our models, what is needed is an experimenter with the cash, willing to have a go...
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Old Jun 12, 2010, 04:40 AM
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Originally Posted by Cybernaught View Post
I don't beleive this wing's slow handling performance....
http://www.youtube.com/watch?v=e-Y8mvkMwoY

Steve.

Did you have more informations about this wing ? I can not found anything
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Old Jun 12, 2010, 05:43 AM
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Windsor, Canada, near Detroit
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Originally Posted by davereap View Post
Whist the KF might not be suitable for the big commercial planes Ive got a gut feeling that for normal prop private and light aircraft that a KFm2 or 4 would work, providing a much safer wing..yes the wing will stall, but at a much reduced speed, I can have my wing parachuting down with the plane stable and recover by just adding power, that stability it provides surely would be beneficial to a light aircraft, providing the advantage does in fact transfer to the full size..we all know how well it does on our models, what is needed is an experimenter with the cash, willing to have a go...
right on.
we may also build models increasing size gradually as i suggested in my post 862, until the step is more pain than gain.
i think that would be cheaper.
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Old Jun 12, 2010, 06:17 AM
Boooriiiiing.
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United States, TX, Roanoke
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Originally Posted by Dickeroo View Post
It shows this 3D RC jet doing a long tail slide almost to the ground. According to the tags he is using a KF airfoil. Take a look...
That's very close to what I was considering over the last couple of days... I've been planning a KF-airfoiled 3D capable pusher jet. Looks like someone beat me to the concept, but at least mine will be cheaper

I suppose for 3D planes a KFm4 would be ideal? I'm thinking the closer to symmetrical the better.
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Old Jun 12, 2010, 06:44 AM
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I am using KFm4 for all my new aerobatic builds.
Personally I think it gives the best all round performace even to gliding well


Quote:
Originally Posted by Cid156 View Post
Did you have more informations about this wing ? I can not found anything
steve posted his plans and info on his slinger2 here..
http://www.rcgroups.com/forums/showp...&postcount=118
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Old Jun 12, 2010, 07:09 AM
Boooriiiiing.
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Originally Posted by davereap View Post
I am using KFm4 for all my new aerobatic builds.
Personally I think it gives the best all round performace even to gliding well
Great! I'll leave the KFm2 to my super-simple builds then. Since I have a whole weekend to myself I might start developing this idea
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Old Jun 14, 2010, 10:12 AM
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Dont take me wrong...there is nothing wrong with using KFm2, especialy as its an easier build.
And the performance from it is fine on most applications.
It is mostly a personal preference , but also depends on how you want your design to fly..
I equate KFm4 more to a symetrical aerobatic airfoil, and KFm2 to the flat bottomed airfoil..but from the way some peoples models fly with a KFm2 you will be hard pushed to tell any difference

Here is yet another KFm4 build.. a 28" span Nutball
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Old Jun 14, 2010, 04:18 PM
Jack
USA, ME, Ellsworth
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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.
Here is a link to an 8 foot flying wing, that was a KFm1 and the Zagnutz was his inspiration for it. It flew pretty nicely.

http://www.rcgroups.com/forums/showthread.php?t=998356

Jack
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Old Jun 15, 2010, 12:34 AM
just Some Useless Geek
Chicagoland
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Originally Posted by davereap View Post
Yet another KFm4 build...
Sorry to rub salt in, mate, but I'm gonna hafta do one in the ol' Red, White, and Blue if you keep that up. Tell yer man to hang on to the ball next time, eh?
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Old Jun 15, 2010, 03:04 AM
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"Whist the KF might not be suitable for the big commercial planes Ive got a gut feeling that for normal prop private and light aircraft..."

The irony of GA aircraft that are stall and spin resistant is, I have read, a higher rate of accidents. It is supposed that having such an aircraft tempts pilots into getting closer to the limits of their aircraft than they might otherwise and suddenly they are over the limits. We repair or discard our judgment failures, they tend not to be so lucky. I have also read that the drag associated with KFm wings seems to become too large even at the relatively low speeds of GA's. Great air foil for us, not so good for people sized machines.
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Old Jun 15, 2010, 03:27 AM
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it's that fellow Reynolds...

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Originally Posted by Siliconserf View Post
"Whist the KF might not be suitable for the big commercial planes Ive got a gut feeling that for normal prop private and light aircraft..."

The irony of GA aircraft that are stall and spin resistant is, I have read, a higher rate of accidents. It is supposed that having such an aircraft tempts pilots into getting closer to the limits of their aircraft than they might otherwise and suddenly they are over the limits. We repair or discard our judgment failures, they tend not to be so lucky. I have also read that the drag associated with KFm wings seems to become too large even at the relatively low speeds of GA's. Great air foil for us, not so good for people sized machines.
yes, sir, you are right. you are touching a hot issue.
it's the difference that counts, so they say. just as there is the sound barrier, there is a change in behaviour when dropping below certain Reynolds numbers, but we still have not performed tests that let us have proof of where the 'traditional' aerodynamics apply, and where we are into Schmitz realm (about his work, you can see my blog).
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Old Jun 15, 2010, 06:55 AM
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Ashford. Kent. England
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Originally Posted by A Useless Geek View Post
Sorry to rub salt in, mate, but I'm gonna hafta do one in the ol' Red, White, and Blue if you keep that up. Tell yer man to hang on to the ball next time, eh?
The red white and blue combination is great for visibility, so fly the flag, even when the footie is poor..
Your stars and stripes make for an excellent decor...go for it...
The tape decor on this 28"er added an extra 3/4oz at full coverage per side..
The extra weight is compensated by the extra strength the cover provides.
The underside has a simple red cross on the black, which might later turn into a union jack flag... but at the moment its being kept simple...
What was white velco, was colored using red marker pen, to fill in on the design..

The AUW on this KFm4 is 20oz ...with 4.37sqft this gives 4.57 oz sqft loading...slightly higher than my target of 4oz sqft... this is including the 1.25oz U/C and a 4oz 3cell lipo.
My motor system will give 26oz thrust on a 9x5 prop, so it will be just nice..

Compared to my 32" KFm4 Dart-xs this has a lighter wing loading but is a couple of oz heavier... so it will be interesting to compare these two side by side...
The idea of this one is a for chuck about park flier that will cope in a fair bit of wind, much as the dart does...My bigger KFm Nutball being heavier and with a lot more area is more of a steady flier, still highly manouverable but not so suited for wildly throwing about like the Dart was

Like the Dart, I have fitted this with 12gm metal geared servos.. The wild flights with the Dart stressed out the standard 9gm servos, finally ending in stripped gearing.. time will tell on these E-max servos, but they look ok..
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Old Jun 15, 2010, 02:09 PM
just Some Useless Geek
Chicagoland
Joined Oct 2008
2,543 Posts
(Oops! Posted in the wrong thread. Sorry, folks.)

Well, here's my first SDXS on a 2S:
Watch it fly

Note that this plane is heavy because of all the repairs done to it, as shown in the attachments. It has a 19 gram motor and little 6.5 gram servos, but it does pretty well. I really don't think you need a huge motor to make an SDXS fly well.

I built this plane back in August of last year. So far is has had a couple hundred batteries run through it; dozens of hours of flight time, dozens of crashes; been repaired two or three dozen times. Fourth motor. Second ESC. Original servos. Fantastic performer. My favorite plane of all time, without exception.
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Old Jun 15, 2010, 03:06 PM
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Switzerland
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Originally Posted by A Useless Geek View Post
Well, here's my first SDXS on a 2S:
Watch it fly

Note that this plane is heavy because of all the repairs done to it, as shown in the attachments. It has a 19 gram motor and little 6.5 gram servos, but it does pretty well. I really don't think you need a huge motor to make an SDXS fly well.

I built this plane back in August of last year. So far is has had a couple hundred batteries run through it; dozens of hours of flight time, dozens of crashes; been repaired two or three dozen times. Fourth motor. Second ESC. Original servos. Fantastic performer. My favorite plane of all time, without exception.

If you try the progress I try the sdxs
I built this plane back in July of last year. So far is has had a couple hundred batteries run through it; dozens of hours of flight time, two dozens of crashes; been repaired two or three dozen times. Two motors. One ESC. Original servos. Fantastic performer. My favorite plane of all time, without exception.


A video from my beginning (I really start this hobby with this plane)
http://www.dailymotion.com/video/xbb...gress-epp_tech

progress EPP.wmv (4 min 1 sec)
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