Over-Thick Control Surfaces

[Wacobipe]

Terryscustom;20095 wrote: Very interesting. My guess is like the images shown in the first post is that the aileron would have to be rounded LE (center hinged) to have the correct effect so modifying most ARF's would be out to give it a try.

I think you are right that this is not a quick mod for an ARF...I guess that makes me extra lucky that I build most of my planes :smile-new:



I am starting a new build shortly on a Delro 2.5, Raven (composite fuse, foam and balsa sheeted wing/tail) and while it isn't a scratch build...it'll be quite easy to modify prior to covering!

 

[Bartman]

Pistolera;20098 wrote: This is a not-to-scale cross-section drawing of the way my Pitts S1-T ailerons were designed. It was a 1984 factory-built Pitts....the fourth T-model off the line.

if you had symmetrical wings, four ailerons, and the aileron profile looked like that then you either had an S1-11B or an S1-SS. It's possible it was an S1-T that had S1-SS wings in place of the original S1-T wings.

 

[Wacobipe]

Pistolera;20098 wrote: This is a not-to-scale cross-section drawing of the way my Pitts S1-T ailerons were designed. It was a 1984 factory-built Pitts....the fourth T-model off the line.

I am also planning to mod the hinges so that they function like this rather that the traditional hinge types we normally use.

 

[Pistolera]

Well Bart....Hate to say you're wrong....but I have a little bit of time in the T.



It was a full symmetrical wings and aileron (with "fat" leading edges), slightly stretched fuse and rudder, Lycoming AEIO-360 and Hartzell constant speed aerobatic prop. It was THE cream of the crop until the early 90's when the S1-11 came along.

 

[Wacobipe]

So Bartman or Pistolera...are there any formulas for how much thicker the surface needs to be? The info I have says 1/16 inch on both sides (total 1/8") for up for .40-1.20 size airplanes...do you think that is good enough for giant scale or do we need to go maybe 1/8" on both sides? Any idea what the full scale extra thickness might be?

 

[Terryscustom]

Wacobipe;20100 wrote:

I am starting a new build shortly on a Delro 2.5, Raven (composite fuse, foam and balsa sheeted wing/tail) and while it isn't a scratch build...it'll be quite easy to modify prior to covering!

If you do a thread and are going to do center point hinges PLEASE copy me when you start the thread so I see it. I've been pondering doing this with foam core wings, even done some sketches but have not pulled the trigger......I'm just inching to do it though.

 

[Bartman]

Pistolera;20103 wrote: Well Bart....Hate to say you're wrong....but I have a little bit of time in the T.



It was a full symmetrical wings and aileron (with "fat" leading edges), slightly stretched fuse and rudder, Lycoming AEIO-360 and Hartzell constant speed aerobatic prop. It was THE cream of the crop until the early 90's when the S1-11 came along.

you're right, i misread the wikipedia entry but it would be weird for it to have the SS ailerons as it came from the factory as Curtis hadn't introduced them yet and Aerotek wasn't in a position at the time to design them themselves. What was the N number? I'd be curious to research it and see what it was. Was yours still certified when you were flying it?



S-1TAerotek-built S-1C with a 200 hp (149 kW) Lycoming AEIO-360-A1E and minor changes; 64 built.[13] Four-aileron, single-seat, factory-built, symmetrical wing, symmetrical ailerons, constant speed two- or three-blade Hartzell propeller. The top wing was moved forward compared to the S-1S for weight and balance. This model was in production in 2008 from Aviat Aircraft as an "on-demand" manufacture product.[4][10]

 

[Bartman]

Wacobipe;20104 wrote: So Bartman or Pistolera...are there any formulas for how much thicker the surface needs to be? The info I have says 1/16 inch on both sides (total 1/8") for up for .40-1.20 size airplanes...do you think that is good enough for giant scale or do we need to go maybe 1/8" on both sides? Any idea what the full scale extra thickness might be?

it isn't just the aileron, it's the profile of the wing trailing edge also that contributes to the effect. the aileron LE has to be able to pinch up or down against the overhang of the trailing edge contour to restrict airflow through the gap at higher displacements. I designed my own SS ailerons for my S1 project (you can see the lower wings hanging in the background in the first video I posted) and I might have the CAD drawings showing the details of the gap and profiles. if you know anyone with Pitts S1-11B, S1-SS or Model 12 plans you can see it there also. If anyone wants to drive to my place in NJ I've got those plans sets and would be happy to show them to you.



Do a google search for SS ailerons and Kevin Kimball and you'll be able to trace his comments for some insight as to how it's done.

 

[Pistolera]

Bart....my Pitts S1-T N49308, was a 1981 model. Number 4 off the line at the Aviat factory in Afton, WY. N49306 - 07 and -08 were used at the Hilton Masters of Aerobatic Championships, while mine was on hand as a backup plane if needed. My Dad purchased it just after that from Aviat via Bill Thomas in Florida. I bought it from Dad in 1984. I started competing and moved into Unlimited in 1986.



Here's a couple of pics of N49308, although it's still hard to see the "fat" aileron LE's. They really don't stick up very much, but were pretty effective. It was just the sweetest flying aerobatic plane, but alas, was showing its age when I retired from competition in 1991. Sold the ole girl in '92.

20117=12910-EHA Pitts Vertical.jpg

20117=12909-Me w Stan Click's Pitts.jpg

 

[Jetpainter]

Boy that first picture really scales that airplane. I haven't been up close to one in years and I'd forgotten just how small they are.