How much dihedral ?

[Zak]

Hi,

I am building a wing from scratch like the one on Todd's Gym-E.

The center section will be 16" long (built flat) and the two
outer sections will be 8 inches long.

The two outer wing sections should have how much dihedral ?

The wing will have no ailerons and the plane will have a v-tail.

Thanks!

[BMatthews]

I'd say 2 inches from looking at a pic of the Gym-e.

Or make it 2 1/8 and tell everyone it had to have the extra 1/8 because it was engineered that way... :D

[Zak]

Anything more scientific ?

;)

[Ollie]

BMatthews can tell to go for science info.

[BMatthews]

Anything more scientific ?

;)

Allrighty then, 2 3/16 + or - 1/64.....

There is no perfect answer. All else being equal steeper dihedral angles will give you a very snappy response and faster recovery to level flight. Less dihedral will give you a slow turning response and a slower return to level. There's no formula to equate desired roll response to the dihedral, tail moment, rudder size, rudder throw angle and flight speed and the mass moments of the model. All these factors enter into the way the model responds It's a matter of background and following what other folks have done in the past.

So based on my background experience and looking at the pic I "guessed" at the 2 inchs as providing an angle that will offer decent control response if your rudder and tail moment is of similar proportion to the Gym-E. But it's an educated guess.....

[Zak]

Ah! :)

Thank you sir!

[BMatthews]

You're welcome. Be sure to post back or please PM me with how it works out.