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ACE Built Up Wing, Dihedral or not ?

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ACE Built Up Wing, Dihedral or not ?

Old 03-31-2011, 06:55 AM
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cortacesped
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Default ACE Built Up Wing, Dihedral or not ?

I´m in the process of building an ACE R/C Cap 21, but I found the original foam wing a little heavy, so I built a constant chord wing based on the plans created by Andrew Donatelli.

I built it one piece and now I don´t want to cut them in half to avoid warp and misaligning (*).

What do you think ? will it fly with no dihedral at all ? help please.

Thanks

Claudio

(*) EDIT: Sorry for the word, I think it must be "misalignment", ;-)
Old 03-31-2011, 09:34 AM
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coriolan
 
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Default RE: ACE Built Up Wing, Dihedral or not ?

No need for dihedral with ailerons, foam wing are indeed too heavy and sometime of unequal density and weight.
Old 03-31-2011, 09:54 AM
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Default RE: ACE Built Up Wing, Dihedral or not ?

Isn't this a mid wing design? We are talking about aileron controlled planes, so............

A little dihedral with a low wing plane lowers the thrust line and lowers the CG..getting it down into the heart of the wing. With our small and light models it usually isn't needed for stable flight, but I think it makes low wing planes look nice.

With a mid wing or high wing design, absolutely no dihedral is needed, ever...unless you want the plane to look like a scale version of some high wing plane that had dihedral. If so, you will end up with a goofy flying model, like a trainer flies.
I think dihedral with a mid or high wing model makes them look goofy.
Old 03-31-2011, 11:27 AM
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Default RE: ACE Built Up Wing, Dihedral or not ?

[link=http://www.airport-data.com/aircraft/photo/434885.html]CAP 21[/link]
Old 03-31-2011, 11:53 AM
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Default RE: ACE Built Up Wing, Dihedral or not ?

I did the same thing a few years back with a built up wing on the Ace Cap 21. I left the wing flat and with a Norvel .061 it was a blast to fly!!!

Bob Harris
Old 03-31-2011, 06:53 PM
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cortacesped
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Default RE: ACE Built Up Wing, Dihedral or not ?

This is a picture of the wing

Well, Dihedral is not necesary since it has ailerons, but a little dihedral (3/4 inch ~ 20 mm) total at wing tip, will give the plane a better appearence.

I´ll post more pics later.

Regards

Claudio

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Old 03-31-2011, 07:35 PM
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Default RE: ACE Built Up Wing, Dihedral or not ?

I think a little dihedral will make the plane look better. You won't warp it if you use scrap lumber to keep everything square and true as you join it back together.
Old 04-01-2011, 06:23 AM
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Default RE: ACE Built Up Wing, Dihedral or not ?

Hi Claudio,
If I were doing it, I would carefully cut out the shear braces next to the center rib. Then I would slide in an 1/8" center rib on each side of the current center rib and have the ribs slightly angled (tops toward the outboard tips to give you the dihedral you wish). Then cut the wing on each side of the current center rib and glue the wing together. Easy!
Old 04-02-2011, 04:58 AM
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Default RE: ACE Built Up Wing, Dihedral or not ?

The designer of the GP CAP 40, who won a lot of contests, actually designed it with MORE dihedral than scale. That was after extensive testing that showed it needed the dihedral to obtain even control responses.

A low wing plane is more stable upside down than right side up. Dihedral can compensate for that and make it better for aerobatics, with less coupling of control responses. That's why Top Flite provides optional wing tips for the Contender that tilt up, to provide dihedral effect. The stock Contender is a low wing plane with no dihedral, and it is well known for a very nasty adverse roll when using rudder alone. People complain that knife edge is almost impossible without the dihedral.

You can fly it with no dihedral, but it will look better and fly better with some dihedral.

Jim
Old 04-09-2011, 07:12 PM
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cortacesped
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Default RE: ACE Built Up Wing, Dihedral or not ?

Well Finally I took the decision and cut the upper section of the wing, sanded the leading and trailing edges and the spars, inserted a 1/8 center rib and glued together again, which resulted in a total dihedral of 25 mm (1 inch).

I don´t know if you can see it on the picture but I misscalculated the first cut about 3 mm (measure two times and cut only one !! ) so I had to make it again, fortunately there wasn´t any warps or missalignment .

Thanks to all for the advices.

I´ll keep posting pics of the progress.

Claudio
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