Equal wing panels & flaps or not

[Lanny Shorts]

 What are most of you now doing in regards to building with equal  length wing panels and flaps ort
are you building with unequal panels and flaps?

[Brett Buck]

What are most of you now doing in regards to building with equal  length wing panels and flaps ort
are you building with unequal panels and flaps?

     I think for a regular sized (650ish square in 40-60 sized stunt plane) you ought to use about 3/4"-1" wing asymmetry and make 1/16"-1/8" wider outboard flap*.

      Brett

*p.s. and make provisions/be prepared to adjust the asymmetry, like, with removable flaps that you can easily shave down or add to, replace completely with different sizes, and then easily refinish. I have adjusted the size of the flaps like this on more-or-less every airplane I have built in the last 30+ years, and in only one case did I wind up with the original configuration.

[frank williams]

Do the "warts" come in order to carry more tip weight?  or just an adjustment for not enough outboard flap to begin with?

[Brett Buck]

Do the "warts" come in order to carry more tip weight?  or just an adjustment for not enough outboard flap to begin with?

   "Carrying more tip weight" is not a good goal and doesn't accomplish anything, unless you also allow the airplane to roll outboard (which at least I am trying to avoid).

     It's there to make sure you don't have to compromise the tip weight for different load factors. If you have it wrong, it might look like you need much more tip weight in level flight than you do in hard corners. For that example, you have too much tab/extra outboard flap area, because the differential starts to matter more the more lift there is.

     Brett

[kevin king]

I'm not an expert, but laying out a nice symmetrical paint scheme on a plane with unequal size wings can be a nuisance.

[Matt Colan]

Equal flaps or not…my little story and where I’m going on the new airplane

At the 2021 NATS I worked with Brett David and Paul to fix a trim issue with my new plane. Turns out I needed tip weight, and a lot of it. I think I added 1oz over the course of that flying session. After the NATS, I kept working on the trim of the airplane and began adding area tabs to the outboard flap. The bigger the tab the better the plane got. The flaps and wing panels are equal. I ended up with 2 square inches of flap area added to the outboard flap with noticeable improvement in overhead tension and how the airplane flew.

My new airplane I’m going a little further. Full span outboard flap, with the trim tab on the inboard wing, much like Dave’s Thundergazer. Total flap area differential is 4 square inches. I’ll have the flaps removable in case this experiment crashes and burns but I have a good feeling about it.

[Brent Williams]

I am curious about the distribution of additional area of the outboard flap.  Does the concentration of additional flap area at the end the flap via a tab/taper have any different effect in performance versus adding the additional area along the full length of the outboard flap?

[Ken Culbertson]

I have been making my outboard flap an 1/8" more chord since the 70's.  That is just over 3 sq".  I have only had to add a small tab (2 sq") on one ship.  The advent of accelerometers and allowing lighter lines have really changed how I trim for overhead so I normally end up with less tip weight. 

Ken

[MikeyPratt]

Hi Guy’s,
In my humble opinion having the flaps of equal size and length with the exception of the out-board flap tip being 3/32” wider at the tip.  That Magnum had 3/4” shorter out board wing panel to help reduce the amount of over all tip weight needed.  As it turned out, that one only needed 1 ounce of tip weight, so I agree with Brett on this one. 

I know I’ll get a bunch of flack on this one, but switching to solid lines allowed me to use 2’ longer lines in high winds without increasing the tip weight, yes they are a pain in the a-- to keep clean but they do work.  I know a lot of people will say use the spectra lines, they are thinner and less drag, maybe, but I won’t use them on a Nat’s model because I don’t trust them (yet).

Later,
Mikey 

[Lanny Shorts]

Gentelmen, many excellent replies on "flap size/.experiments". But are your wing panels equal with all the various flap
lengths/areas or still having outboard panel shorter? Thanks, Lanny

[Tim Wescott]

Gentelmen, many excellent replies on "flap size/.experiments". But are your wing panels equal with all the various flap
lengths/areas or still having outboard panel shorter? Thanks, Lanny

I don't build & fly enough to be an expert here -- but I can barf back what I've read.

You can try doing a search, but what Brett said seems to be the consensus -- go with a bit more span on the inboard side, and a bit more flap area on the outside.  Somewhere in his voluminous output on StuntHanger, there's a really nice discussion from Brett that basically boils down to saying that anything from perfect span symmetry to about 1.5" more on the inside works, but you'll need to trim the flap area and better symmetry means you'll need more tip weight.

[Tim Wescott]

Especially if you're adding the complexity and weight of exponential flaps anyway, I wonder if it'd be worth it to build in adjustable, differential flap throw.  I don't see how to do it without adding at least a bit of weight, but I've got somewhere between three and six ideas that would work all banging around in my head as I type this.

Then your flaps could be equal area, or your best guess at build time, and you wouldn't have to refinish after refining their trim.

[Brett Buck]

Gentelmen, many excellent replies on "flap size/.experiments". But are your wing panels equal with all the various flap
lengths/areas or still having outboard panel shorter? Thanks, Lanny

   As above, the inboard wing should be about 3/4" - 1" longer. It is not critical if you are willing to adjust the outboard flap area.

     Brett

[M Spencer]

Wants to resist baboons twisting them opposite , hence 5/32 horn wire with 2 in arms filed tapered to 1/16 flat , in pre epoxied lucky boxes .

But we'd like to see the differential set up ideas . Needs stern pushrod side location to avoid flop .

[Ted Fancher]

Equal flaps or not…my little story and where I’m going on the new airplane

At the 2021 NATS I worked with Brett David and Paul to fix a trim issue with my new plane. Turns out I needed tip weight, and a lot of it. I think I added 1oz over the course of that flying session. After the NATS, I kept working on the trim of the airplane and began adding area tabs to the outboard flap. The bigger the tab the better the plane got. The flaps and wing panels are equal. I ended up with 2 square inches of flap area added to the outboard flap with noticeable improvement in overhead tension and how the airplane flew.

My new airplane I’m going a little further. Full span outboard flap, with the area tab on the inboard flap, much like Dave’s Thundergazer. Total flap area differential is 4 square inches. I’ll have the flaps removable in case this experiment crashes and burns but I have a good feeling about it.

Hey Matt; I've got a couple of ships still in one piece and several others in the graveyard that all looked sorta (well, truth be known "very") similar to that on your right wing flap.  Never really had a good explanation for it but....?

Ted

p.s.  If you had asked me to 'splain' it I'd have a hard time doing so...nonetheless, they remained and collected a few fancy beer mugs along the way!  Seemed more positive and "pointable" in response and more equal tension particularly above forty five degrees.  Again...don't ask!

[Ted Fancher]

Do the "warts" come in order to carry more tip weight?  or just an adjustment for not enough outboard flap to begin with?

Oh boy, Frank.  If I still had that Trivial Pursuit in one piece I might still be showing up at a contest from time to time.  Loved flying it!  Flew it in seven Nats with warts like that from 1992 to 2007 and garnered 4 seconds, 1 third and 1 forth and a troubled 7th over a span from 1992 to 2007.

Ted

p.s. Edited for mathematic accuracy!



Just re-read this and realized it isn't remotely a response to the original message!!! Old Timer's Disease strikes yet again.

In direct response to Franks question, yes that is the primary purposes for which I started doing this.  It was my feeling (certainly not my wisdom) that some extra flap area out there would allow modestly more tip weight to be utilized without "hinging" (rolling up and down) during maneuvers in particular to get solider and more positive response in the demanding "top parts" of the vertical/overhead, etc. maneuvers above 50 degrees.  It seemed to work out that way to me so I made adapting the practice more or less a part of my trimming process (why some such additions were less than valuable during appearance judging).

A barely noticable "outward" roll in level flight due to the extra weight became, under acceleration in the maneuvers, seemed to me to provide a more consistent input requirement during "top half of the circle" maneuvers.

Please note I've been reluctant to mention this back when I was competing lest those who know better might excoriate me publically for such foolishness.  Maybe they'll tell me I could'a won more trophies if I hadn't screwed the ship up with such foolishness.

Alas, we'll never know!

p.s. all "salty" language above was intended solely to cause giggles and not to offend myself or others!  :!n~

[Pat Johnston]

Just to throw in an interesting thought, why not make the inboard stabilizer about 3/8” longer to balance out the offset of the wing? I mentioned this to Dee Rice and he had an “ahah” moment.
Pat Johnston
Idaho Skunk Works

[Brett Buck]

Just to throw in an interesting thought, why not make the inboard stabilizer about 3/8” longer to balance out the offset of the wing? I mentioned this to Dee Rice and he had an “ahah” moment.
Pat Johnston
Idaho Skunk Works

   I have tried that and it did more-or-less what you would expect, but I don't like trying to torque the airplane with the tail.

       Brett

[Dan McEntee]

   "Carrying more tip weight" is not a good goal and doesn't accomplish anything, unless you also allow the airplane to roll outboard (which at least I am trying to avoid).

     It's there to make sure you don't have to compromise the tip weight for different load factors. If you have it wrong, it might look like you need much more tip weight in level flight than you do in hard corners. For that example, you have too much tab/extra outboard flap area, because the differential starts to matter more the more lift there is.

     Brett

       Back when I was crawling up the lower rungs of the stunt ladder years ago, that is what the general thought was back then, pack as much tip weight as you could carry and as big a flap tab as necessary to hold the tip up in the square corners in search of as much line tension as you could stand. When I have gotten other people's  previously built and abused models and looked into the tip weight boxes ( if it had one) they were usually like a lead mine. Sometime it was cut open a wing tip , cut some weight out, build and install a box  and start over from scratch with trimming.

   Type at you later,
    Dan McEntee