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-   -   flaprons (https://www.rcuniverse.com/forum/questions-answers-154/11596329-flaprons.html)

meinekeman 03-17-2014 02:38 AM

flaprons
 
can you put flaparons on a biplane to slow it down please help thanks

speedracerntrixie 03-17-2014 04:50 AM

Most biplanes I have seen are equipped with barn door ailerons. Using them as flaps would promote the wing tips stalling before the wing center section leading to disastrous results. Biplanes are pretty draggy so provided that the CG is not too far forward or the airplane being overweight, it should slow down nicely. Maybe more details are in order, what particular airplane is it , what does it weight, what's the wing area and where is your CG?

JohnBuckner 03-17-2014 07:14 AM

It really would help if you let us know what your airplane is. Just calling it a biplane is not much help at all just like a monoplane the variety is enormous for example just because an airplane has two wings does not mean it is aerobatic by any means or that is a slow gentle landing airplane.
Another important question that needs to be answered is what engine and prop size is being used? In addition is your ship four ailerons or two? Propellor size and pitch has a great deal to do with how slowly under good control how slowly and airplane is able to make a landing approach.

As for flaperons I agree with SRT above but go one step further and suggest that flaperons are generally a bad idea on most airplanes no matter, monoplane, biplane, barn door ailerons or strip ailerons. By their very nature with the aileron mix they cannot extend far enough to rival a true decicated flap surface and what often happens with flaperons is while yes you can go a tiny bit slower with the flaperon down but most will tend to carry more power for control during approach and there is no real speed reduction during the approach. One generalization that could be made about flaperons (this does not include true dedicated flaps) is they increase the needed pilot skills dramatically and tend to cause more crashs.

So what ya' got meinekeman?

John

AMA 74894 03-17-2014 07:43 AM

agree completely with SRT and John... typically to get a biplane to slow down takes nothing more than reducing the throttle and maintaining altitude.

need more details to be of much more help ;)

Bob Yeager 03-19-2014 08:52 AM

As for flaperons I agree with SRT above but go one step further and suggest that flaperons are generally a bad idea on most airplanes no matter, monoplane, biplane, barn door ailerons or strip ailerons. By their very nature with the aileron mix they cannot extend far enough to rival a true decicated flap surface and what often happens with flaperons is while yes you can go a tiny bit slower with the flaperon down but most will tend to carry more power for control during approach and there is no real speed reduction during the approach. One generalization that could be made about flaperons (this does not include true dedicated flaps) is they increase the needed pilot skills dramatically and tend to cause more crashes.

I can personally attest to the accuracy of the above! :(

iflircaircraft 03-19-2014 02:43 PM

Most biplanes are akin to bricks with wings. You need to "fly 'em in". Trying to slow a biplane to float in s asking for a disaster.



Tom

speedracerntrixie 03-19-2014 04:07 PM


Originally Posted by iflircaircraft (Post 11763647)
Most biplanes are akin to bricks with wings. You need to "fly 'em in". Trying to slow a biplane to float in s asking for a disaster.



Tom

Not that I have had a lot of biplanes but the ones that I did have landed no more difficult then any monoplanes. Yes they had a bit of drag so I had to carry a bit of power but that was really the only notable difference. IMO most guys simply live with the bad charicteristics writing it off as a design flaw when in fact it could be a few simple adjustments to turn a tiger into a lap cat.

jetmech05 03-20-2014 06:53 AM

A bipe that won't slow down, perhaps your idle is too high or you're nose heavy. A nose heavy airplane just won't slow on approach and won't flair either causing the airplane to bounce down the runway.

Stick 40 03-20-2014 04:40 PM

I have played around with flapeons and it never was good. flaps need to be in close to the body of the plane. I have had good luck with flaps on a couple of p51's.

CafeenMan 03-21-2014 08:22 AM

I've got a couple planes with flaperons and I use them backwards - as reflex - to force the plane down as my planes tend to be pretty light floaters. By adding reflex they're easier to land.

Now if I had a biplane with four full span ailerons and four servos I might try a form of butterfly where two ailerons go up and two ailerons go down just to see what happens. But I would try it at fairly high altitude expecting some nasty stall behavior.

JohnBuckner 03-22-2014 07:13 AM

3 Attachment(s)
In most airplanes I do not recommend the use of Flaperons, Now dedicated true flaps yes thats a different matter and can serve some useful purpose in aiding in the control of approach and departures.

There are other useful purposes like CaffeenMan has noted yes they are not widespread uses but legitimate none the less. In my case I have just one airplane that I use flaperons with for a very specific purpose. The airplane is a glider that I use for 'aerotow and now the chief tow ship is a Great Planes Stearman. The glider is a much modified Seniorita Cadet equiped with a tow release system, It also serves as a quick change twin engine ship with a couple of .25's but thats a different forum.

In the glider mode when under tow this very light seniorita (I have lightened the stock structure significantly with undersized lumber) tends to overclimb the tow plane at its lowest functional tow speed so the ailerons I have used are full span and will reflex up to 15 degrees up and this helps considerably under tow and after release the flaperons are returned to in trail or 10 degrees down if desired.

John

http://www.rcuniverse.com/forum/atta...mentid=1980417 http://www.rcuniverse.com/forum/atta...mentid=1980418 http://www.rcuniverse.com/forum/atta...mentid=1980419

Calvinman 03-22-2014 08:37 PM

Interesting looking Seniorita John, I love the windshield. I am just waiting to maiden my ultra sport 40 with flaps and flaperons(flaperons set to deflect up as Cafeenman suggests. I may not get around to testing the flaps and or flaperons until I have a few flights on her, but it should be intersting.

Calvi

jester_s1 03-23-2014 05:48 AM

You don't need flaps of any kind on an ultra sport. It will slow for landing just fine without them, and won't have any unpredictable stall characteristics.

speedracerntrixie 03-23-2014 08:50 AM

Of course they are not needed but it would open up an extended flight envelope. Imagine mixing the crow with throttle on a switch and performing some very slow down lines. Or with some wind a stationary landing. This is one of the things I tend to advocate, think outside the box. We are flying models so nobody is getting killed if it doesn't work. Granted I suggest against flapperons because experience tells me that dosent work. Same goes with flying techniques, some guys just don't get it when I make the statement that they should stop setting up their models and flying then as if they were full scale aircraft. That leaves lots of performance on the ground.

Calvinman 03-23-2014 04:52 PM

Hi Jester, Yes I know the Ultra Sport does not need any flaps, it is for me just something I want to try, like Speedracerntrixie says just to push the envelope, maybe just do some hovering in a stiff breeze:cool:

Calvi


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