Quadratwirl

[rus1]

I've had lots of fun and great success with Twirl, but the Quadratwirl I just built flies poorly.

I took great care to place the CG as shown, but she barely flies. Are there known issues with Quadratwirl?

[philby]

rus1 what problems have you got, I have recently built the quadratwirl after great fun & success with the twirl, but find it a handful in comparison to say the least. The biggest problem I have found is it wants to "Dutch roll" (rapid oscillating left/right roll) a lot of the time.
I have found that the rudder is very sensitive especially as the speed builds up. It helps to have quite a lot of exponential dialed in don't have too much movement and don't let the speed get too high.

[alfoot]

rus1,

I've just seen both of your new threads on the Quadratwirl.

I think that we need more details on the nature of the problems you are having.

I would start by assuming that you have built it in accordance with the plans, the angles are all correct, and that the bracing has been added because it IS functional and crucial to flight. The weight should also be within the declared values if it is to fly reasonably. Too heavy and, like all lightweight aircraft, it will not fly too well. Finally, it was designed as a "slow" flyer and, as Philby says, it does have a dutch roll when flown at high speed. Expo (lots of it) and a sympathetic rudder thumb can assist, but it's actually better to fly it slow.

I had a number of movies of it in flight on Putfile but that site sems to have vanished. I can put some on YouTube if you would like.

Hope this helps,

Al

[rus1]

I have had so much fun with Twirl, having built and flown 4 of them, that I was looking forward to the Quadra Twirl.

I'm using a dual-stator outrunner turning a 10x4.7 slo fly prop, and a 3 cell 800MaHr Li-Po. This is the same power plant I use on the Twirls with vertical performance and unlimited hover.

The problem is the Quadra Twirl seems under-powered, and when in flight I get that side to side dutch roll oscillation. I have tried slowing it down with nose high, but still need to be on the sticks alot, as it just seems unstable.

I built it to plan, with CG correct and bracing of the rotors as shown. I experimented with CG by moving the Battery a little forward or backward. Forward gave more stability, but I couldn't lift the nose. Backward was too unstable to fly under control. QuadraTwirl looks cool, so I would like to "make it play".

Any thoughts?

[rus1]

As you can see in my new post, I got lucky and solved the problem I was having with Dutch Roll. I took all the dihedral out of the front wing, and now she flies wonderfully. Thanks for your interest and suggestions.

[alfoot]

rus1,

That's good news, glad that you got it sorted.

Does it still turn ok at very slow speed (I mean with the nose almost vertical and speed at walking pace or less)?

How about getting some video of it?

Al

[rus1]

Al,
It still turns well even with the nose almost straight up. I'll get a helper to take a video so you can see. Will post on youtube and let you know.

Just put a couple of videos up on youtube of my Blu Cor Fan Fold foam Twirls.
you can see them at www.youtube.com/rus1ify On one of them I took video and flew at the same time, so learned a helper is really necessary.

Thanks for your interest and help!

Russ