A. N. Other's flaps.

[rustler]

In the H. Rush's flaps postings, Ted F. mentions an improvement with the Profile Cardinal by slicing 1/2" off the flaps. I'm all for improvements, but wouldn't this invalidate the model for e.g. Classic?
For the experts - could you get the same effect by reducing flap throw? e.g. so that the flap T.E. ends up as much below the chord line in both cases? If you see what I mean 

[RandySmith]

In the H. Rush's flaps postings, Ted F. mentions an improvement with the Profile Cardinal by slicing 1/2" off the flaps. I'm all for improvements, but wouldn't this invalidate the model for e.g. Classic?
For the experts - could you get the same effect by reducing flap throw? e.g. so that the flap T.E. ends up as much below the chord line in both cases? If you see what I mean 

Hi Ian

Yes you can get much the same effect by reducing the amount of movement or ratio to the elevators

Regards
Randy

[Howard Rush]

It depends whose flaps they are.  Reducing the throw is the obvious choice for one's own flaps.  The X-Acto knife is the first thing that comes to mind for somebody else's. 

[Doug Moon]

It depends whose flaps they are.  Reducing the throw is the obvious choice for one's own flaps.  The X-Acto knife is the first thing that comes to mind for somebody else's. 

VERY true!!!...

[john e. holliday]

As Dennis A. stated, wouldn't you get the same results by cutting the length of the flaps?  I seem to remember one of Bob G.'s Nobler's having the flaps cut and glued in several places.  DOC Holliday

[RandySmith]

It depends whose flaps they are.  Reducing the throw is the obvious choice for one's own flaps.  The X-Acto knife is the first thing that comes to mind for somebody else's. 

The Xacto knife is a perfect choice for most airplanes that have ..no..way to adjust the flap travel, and most airplane do not have any way to do this.
Mostly you will see airplanes have adjustable elevator horns that you can vary the flap vs elevator ration to each other.

However  the question  was    would reducing the flap travel alone  do the trick, it will do much the same

Randy

[Mark Scarborough]

I think if I recall readin Ted Fanchers article on the Imitation, he did extensive testing with flaps, gradually shortening them and flying the plane. I dont recall exactly but I think that broader chord flaps increase the handle loading with the same effectivness. I beleive that Teds summary was to the effect that he prefered full span flaps of a narrower chord.

[Steve Helmick]

I'm not 100% clear on why the Profile Cardinal and "Classic" are used in the same paragraph. No version of the Windy U. "Cardinal" is "Classic" legit, so it matters not.

The second point I'd make is that there is no rule in (our) Classic rules that give anybody authority to deny entry or disqualify an entrant for any modification to a Classic era design. The rules provide for this with points adjustments. Not many organizers use anything but Appearance Points over here.  Steve

[Ted Fancher]

I think if I recall readin Ted Fanchers article on the Imitation, he did extensive testing with flaps, gradually shortening them and flying the plane. I dont recall exactly but I think that broader chord flaps increase the handle loading with the same effectivness. I beleive that Teds summary was to the effect that he prefered full span flaps of a narrower chord.

Mark,

Yes, that's correct. Still no time to sit down and go into my thoughts on this in depth but I encourage anyone who can access them to go over the old Wild Bill articles about Controline Aerodynamics made Painless and concentrate on his thoughts regarding movable surface chords and hinge loading (the amount of force required to deflect a surface of the same area but different shapes ... long/narrow vice short/wide.

The primary consideration in my thoughts about flap configuration has always been: 1. Recognize that their primary purpose is to increase the amount of lift a wing of given area is capable of producing. 2. Recognize that lift greater than that required is superfluous and complicates aircraft trim in other areas. 3. That the negative pitching moment associated with flaps has both positive and negative results.  The positive being that they move the neutral point of the whole airplane aft allowing the CG to be located further aft ... ideally to a point that increased G-loads due to acceleration in high winds/consecutive maneuvers are centered at or near the CG thus eliminating the need for constantly increasing amounts of pitch force to maintain the required radius.

My bottom line is that wings should be as small as possible and still create the necessary amount of lift through judicious use of flaps that create as little additional control load (amount of force necessary to deflect them) as possible to do their job.  Wings on competitive stunts should be as small as possible to maximize performance in winds.  This is simply because tethered stunt ships have a lot in common with stunt kites and the bigger they are the more they are affected by the winds ... and essentially none of those affects is advantageous.

Unflapped span is counterproductive in this scenario because any span that doesn't have flaps operates at a lower coefficient of lift and thus requires that the wing be larger than necessary to obtain the requisite lift.  This hasn't driven me to use full span flaps, by the way.  I generally make them no longer than the wing span without the tips or a little shorterf on the inboard side.  I have some theoretical reasons regarding tip vortices, etc. none of which I can point at with great conviction.

More at some point.  The contractors are here and we need to beat up on them about the paint job.

Ted

[RandySmith]

I think if I recall readin Ted Fanchers article on the Imitation, he did extensive testing with flaps, gradually shortening them and flying the plane. I dont recall exactly but I think that broader chord flaps increase the handle loading with the same effectivness. I beleive that Teds summary was to the effect that he prefered full span flaps of a narrower chord.

Hi Mark

I have flown 2 of the same planes with full span flaps and partial span flaps, with about 4 and 5 inches fixed at the tips, I did not notice any difference in handle pressure to move them,  note, they were both the same area.
At best it is so close to the same that you can't tell. Of course my CG is located more aft, rather than forward as some use.
So I only move the controls so the flaps may not move but about 10 or 15 degrees for round maneuvers , eights and the like, I don't think I am using more than 20 to 25 on hard corners.
My findings may be differant than others that use a "lot" of handle movement, I have never used a very high wing loading with huge flap movements to keep the plane with enough lift to turn.

If you have too much pressure on the handle one thing you can do to trim this out is just simply move the overhang of the handle connectors back toward your hand
Moving the overhang back reduces handle pressure and resistance.
Moving it out increases handle pressure..what some call "stick pressure"

This is also very beneficial in high winds as you can reduce the handle pressure, and it doesn't take much to make a substantial difference in winds.

I am in complete agreement with Ted about wing size, When I first made the larger Stuncraft airplanes back in the mid 1970s, they were over 725 sq ins.
I quickly found it was too large,so I went to 700 sq in.  The very next one was 670 sq inches.
The latest SV series are 3 sizes  (not including the 40 sized ones) 640 sq inches , 670 sq in, and  the  SV-R series is 690.

I think also there would be a big benefit to having adjustable flaps ratio,maybe rather than an adjustable elevator, or both.
I have 2 ships here that have both, I may need to take them out and revisit this...

Regards
Randy

[Paul Walker]

[

More at some point.  The contractors are here and we need to beat up on them about the paint job.

Ted
[/quote]

Super.....At least you have a contractor left to beat up!!

[RandySmith]

[

More at some point.  The contractors are here and we need to beat up on them about the paint job.

Ted


Super.....At least you have a contractor left to beat up!!

I feel for you guys...Having gone thru that one myself, too many times!

[rustler]

Thanks everybody for some good productive input on this.

I'm not 100% clear on why the Profile Cardinal and "Classic" are used in the same paragraph. No version of the Windy U. "Cardinal" is "Classic" legit, so it matters not.

Steve - The reason I put "e.g. Classic" was to try and say presumably this mod could end up making a better flying model, but disqualify it from Classic, if applied to a Classic model. But it sounds as if in the U.S. this is would be an acceptable mod. We're a bit more strict over this side of the pond!

[Ted Fancher]

[

More at some point.  The contractors are here and we need to beat up on them about the paint job.

Ted


Super.....At least you have a contractor left to beat up!!

Oooh, ouch. Paul.  That sounds like a story I don't want to hear more about!

So far -- in today's economy -- our general contractor seems more than anxious to keep us happy. His guys have been super and he's whupped up on a couple of the subs that weren't up to snuff.  It's a long process even though they're pretty much at it every day.  Getting tired of living in the garage with all the airplane stuff stashed in a shipping container in the driveway.

It's going to be nice though.

Ted

[Brett Buck]

Thanks everybody for some good productive input on this.

Steve - The reason I put "e.g. Classic" was to try and say presumably this mod could end up making a better flying model, but disqualify it from Classic, if applied to a Classic model. But it sounds as if in the U.S. this is would be an acceptable mod. We're a bit more strict over this side of the pond!

   Well, not really. The PAMPA Classic rules do not permit anyone being disqualified for anything. Deviations not in the spirit of the rules is supposed to be covered by loss of Fidelity points, but almost no one uses those, so there's no *competition* penalty for that. It will make your peers think less of you, and since that's really the only purpose of the exercise, it sort of defeats the purpose.

    And I know you didn't mean to associate the two items, but for clarity, I think the Profile cardinal (or the full-fuse version, either) doesn't qualify for either Classic or Nostalgia 30, not even close as near as I can see.

    Brett