Increasing roll rate
 

Hi
Below are a few pics of my 3D model with OS 50SX. The wing span is 56" and wing area is 950 sq. in. including the ailerons. The area of the ailerons is 205 sq. in. including the gap between the 2 ailerons which is about 20 sq. in.
The roll rate is too slow..... about 1 roll in 1.5 seconds.

How to improve the rolling???

Thanks
Vikas

RE: Increasing roll rate
 

Maybe you could increase the throw??

RE: Increasing roll rate
 

Just wondering if your servos are stout enough. My Funtana rolls faster at 1/2 throttle then it does at full throttle. The 9101s are just not strong enough to hold full deflection at full speed.

david

RE: Increasing roll rate
 

Maybe try setting up differential ailerons.

RE: Increasing roll rate
 

don't have so much taper, wider at the tip would help, have you sealed the hinge line, that will improve roll rate. Its strange that is happening as they look big enough and have more than enough deflection. Tapered back leading edge would help but reduce your wing area.

RE: Increasing roll rate
 

Think it may be a blow back issue..........

RE: Increasing roll rate
 

Increase the throw on the ailerons. You can also add aileron throw to the elevator if you are using split elevators.

RE: Increasing roll rate
 

I was gonna say seal the gaps, but they look pretty tight up to the wing. Shouldnt be too much of a problem. The ratio of aileron area to wing area may not be perfect. I have found this out on foamies a lot. If they dont have enough aileron area, they dont create a powerful enough airfoil to overcome the resistance of pushing the wing through the air. On this plane it shouldnt be too bad of a problem, just throwin out ideas.

RE: Increasing roll rate
 

Thanks for the suggestions.
The throw is approx 45 degrees. Will increasing this help in rolling faster or create more drag?

David:
Your reason seems very logical. I am using Futaba 3001 and I feel that at low speeds the aileron is really responsive.....it becomes difficult to control the model while landing at high throws. it is quite possible that due to the high speed, the servo is not holding the ailerons. i have a few 9202's lying around..... must try those next time.

Luke:
What is a blow back issue?

After trying the above, if not successful, the only way is to add more aileron area. I did the same on the rudder and now the model holds knife edge but will not climb. Again I am using 3001 servos for rudder and really feel that the servo is not holding up.

This is the first time since I started flying about 12 years ago that the servo holding power issue has come up. probably because this is only my second 3D model.

Regarding adding aileron throws to the elevator, I have made the provision to put 2 servos at the back with pull-pull setup while building just for this purpose but this really gets the CG out. The plane is already 2.4 Kgs with an OS 51 SX. So, I don't really want to do this until I put my OS 91 FS on it.

Thanks for the suggestions. I will probably first change the servos

Vikas

RE: Increasing roll rate
 

Another thing to think about. Those ail's are pretty thin. Is it possible they are flexing under load when being pushed to full deflection and not giving you full roll rate?

A case in point is look at the FuntanS's ail's. These things are very thick at the root and are very strong. The servos need to push them but if they flex, they will not be effective.

RE: Increasing roll rate
 

i've also found if you have too much throw it doesn't help. the ailerons will only be effective to a certain angle. try giving a little less stick in a roll to tell. full 3d rates aren't necesarily the most manuverable, only help when little airflow going over them

RE: Increasing roll rate
 

Thanks for the ideas. will try somethings this sunday.

Thanks
Vikas