Problem with the torque roll.

[Tikka]

Hi all.
I've just bought my self a nice Composite Arf 102" Extra 330.
If flies great, but I have problems getting it to torque. I was flying yesterday, and everything was better than expected. It torque rolled very well, using 2-3 sec pr roll. But today, it didn't wanna roll at all. I helped with the ailrons, but when I neutralized them, the plane stopped torque rolling. The weather was the same as yeaterday, perfect, with no wind. How come this happens? What can I do to make my plane torque roll like the ones seen on alle the film clips in here? I'm using a 3W 106, with a MCS 28/10.

Best regards

[Temptation]

Maybe it's just the airplanes way of telling you that it didn't want to fly in that cold. That is some smooth ice you guys are flying off of. Is that a frozen lake? Looks very nice.

Mike Darr

[teryn]

why would you ever assume that it should keep turning with neutral ailerons? the natural roll damping is too high to sustain the roll. Most airplanes need ailerons because of this.
You can't expect to jump into something so complicated on an airplane that you don't know the intracacies of and expect instant answers...There are no magic buttons to press to get torque rolls: it takes practice, frustration, a lot of experience and a very keen sense/understanding of your plane. Good people make it look easy.

[Tikka]

Yes, it is a frozen lake. We have many of those here where I live.
Maybe I should explain myself a little better regarding the torque roll. I have no problem performing a perfect torqueroll for minutes with other planes. I've had many differen't planes, my best plane was the 3W Votec 322 122". This plane torqued easily without any use of ailrons, and I have had smaller planes, aslo torquerolling without use of ailrons. But this Extra I have got now, will not do so. And this is why I posted this thread. I have seen many videos, including one where Joe Hunt flies the same plane as I've got, and his plane torqurolls without any help from the ailrons. I'm not an expert in flying, and I'm not an expert writing in english, so I may have problems putting my thouhgts into writing. Thanx anyway, for the answers I've got, so far

[teryn]

The fact that it changed overnight is bizarre. It sounds like you have experience and know what you are doing (didn't jump into it yesterday and wonder why you can't torque roll like everyone else). As you know, what's driving the torque is load on the engine from the propeller. You can try different propellers to get the torque to be higher (which will put a different load on the engine) but you may sacrifice performance in other portions of the flight envelope. It's not immediately obvious what would increase torque more (either longer diamter or more pitch). I am not sure.

I would be skeptical about making the claim that zero aileron can sustain a nice roll with these planes. The roll damping to the inertia ratio is too high, and usually damps out the torque effect on the models. Remember, that there are dynamic scaling issues here that change things around and make it different (and less intuitive) than our full-scale counterparts. And usually with full-scales you will notice aileron in on the torque roll also. By the way, the model torque scales with 1/n^4 (1 over n raised to the fourth power), where n=scale factor for the plane. If it a 1/4 size plane, then n=4.

I have written a Win32/DOS program to analyze scaling effects between full-scale and model (very interesting stuff). In other words, if you want your model to fly like the full-scale, you enter the full-scale values (for example, HP) and it will tell you the HP that you need to run with your model in order for it to "perform" like the full-scale. I did it for the CAP 232 one time and was amazed at what I saw. You'll need to download it and run it in a DOS box (sorry, I don't know how to write GUIs for Windows), and it will prompt you for input values. Let me know if you have any questions.
www.terynd.com/publications/scale.exe

[hillmanr2]

try modulating or pulsing the throttle. It could be that you were smoother with the throttle the second day

[yakwrecker]

If you leave the throttle at a steady setting the torq with slow greatly because there is no force acting on the prop, it is smooth so it will stay slow and steady but it will roll a little. When you keep bumbing the throttle like what you see a lot of guys do they will torq abound better because the prop loads change as you bump it. also I noticed that comp arfs dont toq as well because they have very good roll stability and they arnt designed to roll due to anything other than ail. input

[babflyer]

I would say just give it another go without changing anything. Some planes like to be laying on their back more than others and I suspect that maybe you were in the sweet spot one day and for some reason your perception of where that spot was was a little different the next day and that caused you to never get to that spot. Forget about the ailerons, while in a good torque roll even oposite aileron wont stop the rotation on some planes. Personally I would take a look at how easy it is to hold a hover with the plane, does it require constant elevator input? If it does require constant elevator or rudder you might consider a thrust angle change.

[Vic3D]

How about that Funtana with no rudder? LOL

[teryn]

	Quote: Originally Posted by yakwrecker
	If you leave the throttle at a steady setting the torq with slow greatly because there is no force acting on the prop...

Not true, aerodynamic drag is a force acting on the prop at all times, and torque is simply a manifestation of this (a force....in this case, aerodynamic). Torque varies but it NEVER disappears. Torque is simply a force times distance. So torque is there all the time as long as the prop is spinning. period.

[JohnnyKatana]

its possible that the plane isnt completely vertical, causing it to stay still
once the plane is completely vertical is\ts should have no problem tourqing

[Tikka]

I have no problems holding the plane vertical.
I went back to the frozen lake again today, for some more flying. And today also, the plane wouldn't roll very much. But something is a bit strange. If I use right ailron, the plane starts rolling to the left, and when I let go of the ailron, is stopped rolling for a sec, then slowly picked up the rolling again, then it rolled 2-3 rounds, and stopped again. I put in some left ailron, and it started slowly again. If I decend, it rolls quickly, but I can't decend for ever. Once I pump the throttle, it stops again. Well, I have a new plane on the table, a 3,1 meter Extra. I hope this one will torque more.
Thanx for all the answers I've got.
You're great guys.

[johnyrcu]

not that you have a problem holding it vert. but it's a new plane (to you) and the comp arfs look like they are leaning on their back when they are vertical. I have one.

[Tikka]

Maybe you're right. Haven't really thought of that.
One of the first things I hade to change was the angle of the engine. I boltet it straight to the firewall when I first put the plane together. But after a few flights, it felt a bit wrong in hover. I had to pull the elevator bacj constantly. I put some washers between the lower part of the engine and the firewall, giving some more up thrust. Now the plane stays upright on its own in hover, very little elevator input. I also need to trim the plane between the wingtips, as it will drop the left wing when I pull hard from straight flight, and into hover position. But it is a great plane, it is my second 2,6 meter from Composite ARF

[Ion01]

I don't really know much about this stuff but knowone has mentioned thrust angle having an effect on the torque roll charactoristics of an aircraft. Maybe this is something that is causing what you are seeing.