Dihedral glider - aileron conversion

[0__0]

Hi everybody,

As someone who seldom has the time to train on advanced airplanes, I started enjoying gliders, which offer relatively forgiving flight opportunities. Having flown 3 channel gliders before, I naturally want to move to a full 4 channel one.

I have actually found many interesting glider plans, yet they all compensate their lack of ailerons for the beginner friendly dihedral. My question then is : Would it be reasonable to flatten those wings out, and cut out a pair of ailerons ?

 

[Merv]

...Would it be reasonable to flatten those wings out, and cut out a pair of ailerons ?

Ive never flow a glider, so take my comments with a grain of salt.

Yes, I often take a plane with dihedral and make one with a straight wing. The dihedral adds a bit of stability, if you put the plane in a bank, the dihedral will auto level it. I learned to fly on a 4 channel plane with dihedral.

There is no need to remove the dihedral in order to add ailerons. The key to ailerons, make sure the up aileron goes up more than the down aileron goes down. This will cause more drag on the down wing and prevent adverse yaw.

 

[quorneng]

No need to reduce dihedral.
Any plane flying straight and level will turn if a roll is applied. Ailerons applies the roll directly. The rudder only creates roll by a secondary effect and needs a good measure of dihedral for rudder yaw to create roll.
What tends to catch people out who have learned with just a rudder is how fast ailerons impart a roll although with a big wing span glider it does tend to slow things down quite a bit.
Ailerons on a plane with a really large span wing and a short tail can impart some secondary effects. As Merv points out it is caused by the fact the DOWN aileron creates more drag than the UP one with equal deflection.. In extreme cases this effect can actually prevent a plane from turning no matter how much roll has been applied. The remedy is to reduce the travel on the DOWN aileron so the drag matches that of the UP aileron.
On a plane with modest proportions the dissimilar aileron drag will likely not even be noticed.

To make a glider "comfortable" to fly you still some dihedral and a good size fin and that has nothing to do with whether it has ailerons.

 

[MaxTheFliteFreak]

Dihedral makes the plane inherently stable, and the idea for gliders is to be as inherently stable as possible so that minimal input from the operator is required, thus increasing efficency yada yada yada... The take away is that you should add ailerons (and flaperons if you want to get fancy) and keep the dihedral so that the plane will still be stable through the air.
Goodluck, have fun and happy flying!

 

[danskis]

All of the gliders on this page have dihedral and ailerons. Notice there isn’t a lot of dihedral. You have to use the ailerons to fly them. You don’t need much aileron movement for it to be effective. 5mm down and 10mm up is a good start.

https://www.hyperflight.co.uk/products.asp?cat=RC+Models&subcat=Electric+F5J+Gliders

 

[Aireal Anarchist]

If your building your own power glider.....make the rudder large.... aileron turns kill altitude.....learning coordinated aileron/rudder turns to keep the glider level will lose less altitude.

if your making a glider even out of heavy foam core 60" wing span or more I recommend flaps as well to be used as airbrakes
I built a foamcore with 78" wing span and heavy as it is being made out of foam board it still doesnt want to come down unless I use the airbrakes even then I need a football field length to get it down....gliders like to glide


here is the first large foam board glider I built with NO dihedral and I also built a wing with polyhedral ......the no dihedral flies much sportier under power using ailerons and the polyhedral flies very tame like the Gentle Lady style gliders

 

[danskis]

A folding prop will increase your efficiency at least 20%. It makes a significant difference in reducing drag.

 

[Piotrsko]

Listen to @quorneng , he knows stuff. Ailerons kill altitude in a turn only if you don't add some up elevator. I can waste a page and give you a headache as to why, but: less lift in a vertical direction during turn.

Inherently stable takes the workload out of flying by not being on the controls constantly. Having a very twitchy glider is really helpful.on those light lift teensey thermal days but they ain't enjoyable except for winning a duration contest. Or combat.

The real important point to make: rudder will now be over on a relatively unused stick in a 4+ channel teansmitter. In 50 years I haven't been able to train my left hand, but YMMV.