Just wondering if this would work...

You know when you're hovering..and you're ailerons become almost non-reponsive? Well I was wondering if it would be possible to use little fan units to control the roll instead of ailerons..or maybe in combination? Is this even possible?

Anyway I've got a little drawing to illustrate this better.

Sure, it would work. I have always thought that it would make a plane flat spin like a frisbee if you stationed one at the tail.

I wonder how fast it would drain a battery though? In anycase, by the time my budget recovers from my last experiment (see picture below) I will definatly have to try this.

I'll probly start out with them as a combination...unless it gets to heavy with the fans and servos.

I think that unless you are trying to do outrageous tork rolls, it's a waste of time. Obviously, you could get some kind of fundamental roll control out of it, [for just flying around] but having that much weight stationed outboard on the wing tips is not a good thing. That's why I thought the best application of this idea would be maybe a small single thruster for improving flat spins and / or for tork rolling a 3D plane.

Maybe you could have the fan in the fuselage and run ducts out to the wingtips. Actually there is a fan at the front of the airplane already. Maybe you could run ducts from that.

Hmmm how complicated can we make it ? [8D]

Hehe, even if it would only fly normaly the "cool effect" would be huge...

To reduce spool-up time, both motors would need to be running all the time, with one slowed when the other increases its rpm.
It don't think the response would be faster than aerodynamically possible with ailerons in the main motor slipstream, as is currently the fashion.
A positionable jet outlet would be more practical, with the thrust generated on the centerline by a single motor exhausting into a bifurcated duct.. one feed to each tip, pointing aft nominally, and variable around a span wise axis to generate the roll moment.

Would it really take that long to spool up? I know my zagi takes less than a second to reach top rpms...

Very interesting, but wide, full-span ailerons work fine for me for cancelling engine torque in hover, allowing rolling against the torque. One little trick I have used is to increase the aileron chord in innermost 15 or 20 percent of its length - the portion that is swept by the propwash in hover - to give stronger roll authority against torque, and the increase in servo torque required at high airspeed is only about ten percent. The ailerons should extend almost to the fuselage side, however.

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Imagine a 1 second delay in aileron response.

The motors might add more roll inertia. So roll response will be tardy?

Even if it is slower to respond..in combination with ailerons...it would probbably help..

You also need to factor in the loss of wing efficiency due to having big gaping holes in the lifting surface. Those fan holes are going to act like big spoilers in a bad way in any sort of normal flying mode where there's a load on the wing. But if you did try it I'm sure it would be interesting. The odd thing is that you would have to use flat sectioned blades with no twist to them. As the rotation direction changes the blades would reverse their leading and trailing edges. Or I guess you could use variable pitch helicopter tail rotors and just move the pitch as required and run the motors all the time.

So -you have not heard of 35-40% ailerons?
on small planes -we use em all the time
on bigger stuff - 25% is enough to make rolls
lower aspect ratio also speeds up the game --

personally... for slower rolls... I just don't move the right stick as much... but hey..thats just me....

i remember some pics and an article in MAN where they mounted a heli tail rotor on the boom of a fun-fly plane and powered it with a torque rod from the rear starter shaft of an OS .32. can't remember if it was used for pitch or yaw but i do remember them saying it was very responsive and allowed some pretty wild flying.




dave

Lets take it one step closer to the edge...
Using a Co2 cartridge for power/propelent,the valves from a gas retrat setup, some light weight tubing, we put a couple of nozzels at the wig tips. Now you have an attitude control system akin to what was used on the X-15, or the shuttle.

FMA Direct has a park flier that has a fan in the tail for rudder control.

Why not use the fans out on the wing to provide added lift in taking off. With the right motors and correct positioning for balance, you might even hover![8D]

This is a scary thread.

With all the propeller caps spinning so fast you shouldn't need any extra fans

Larry

Why not mix the elevators as elevons to use them as stabilators, taking advantage of the extra airflow along the fuselage?

Hey,,, I already got a name for it. Extra Crispy lol !!

I didn't think Chickens could fly

Like I said before "This a very scary thread"[:-]

Larry

Flyboy- I actually like the idea of coupling the elevator to the ailerons. This would enable the elevons to act like elevons and would be highly efficient, as they are directly in the aircrafts prop wash. I mean yes I'm sure the wing-mounted fans would work but, to me it's just very impractical. In addition, I'm really into aerodynamics but, I am certainly no aerodynamicist and I can only imagine the time and money that would go into such a project with such uknown aerodymamics. But hey, it's pretty neat concept!

Hi Guys, This is a very interesting idea. You do know that there are several sizes of electric ducted fans available that could be used. Also, with some computer radios, you would be able to turn the fans on and off to be used in conjunction with or independently of the ailerons. And a third mutation of this would be the ability to reverse direction of each fan in conjunction with the aileron direction. As in a left roll, the rignt fan would direct thrust downward, while in a right turn it thrusts upward.

You could also throttle the fans in proportion to the aileron input. The more deflection of the aileron, the faster the fan spins...

Being a dedicated helicopter flyer my self, why not use, as stated, collective pitch tail rotor blades in each wing, with both blades being belt driven by one dedicated brushless motor in the middle of the plane, along with one (or two) servos to control the pitch rod for each rotor. It would be fantastic.. .

This way you get instant response time without waiting for engine spoolups, not to mention you use less power all around with more thrust per unit.