Torque Burners

[smrt1337]

I came across this discussion in the Hip Pocket forum:http://www.hippocketaeronautics.com/hpa ... ic=17833.0 and the idea of a torque burner interested me, but I'm not sure what it actually is. (i couldn't find the the discussion cylynn was talking about ) The description of a torque climber Maxout gave failed to satisfy my curiosity. Could someone please explain to me how someone would go about making a torque burner and if thats even legal?

Thanks!

[bernard]

viewtopic.php?f=191&t=6085&start=15#p264807

[jander14indoor]

The one successful torque burner implementation I've seen was done as follows.
A thin wire was attached to the fuselage at the point or points you want to split the motor.
Another small tube was inserted in the motor loop at the desired position and trapped while winding.
Motor mounted to plane.
The small wire is threaded through the tube at each position preventing the rear half (or thirds, or whatever) from turning and contributing to flight.
Pull the tube in the motor out so it doesn't fall from the plane and stop the time, but leaves the wire threaded through the motor.
Plane launched normally.
As front half of motor unwound, the rear half pulled back on the wire eventually pulling the motor free of the wire allowing the energy stored in the next section of the motor to contribute to flight.

Why do all this. At low sites you have to back off a lot of turns (fly with a partial tank of gas) due to the high motor torque when fully wound to avoid spending most of the flight bouncing of the ceiling with the risk of ending the flight early. With a torque burner its like launch your plane with a fully wound, but short motor. Now it just barely flies to the ceiling, but returns early and you wind again, except you DON'T have to wind again, the wire releases before you land and the plane flies back to the ceiling.

At a high site, you'd NEVER do this.

Warning, this is a past expert technique. It is a beauty to behold when it works and can dramatically increase flight times at low sites. BUT, it takes MANY hours of experimentation to do right. In 15+ years of coaching and supervising in Wright stuff I've seen a grand total of ONE person do it right, and only heard of a couple of others. And each of those were ALREADY nationally competitive flyers with years of experience (in those years WS was consistently B and C so you could fly for 6 years in SO) looking to beat themselves and each other. The two I know the names of went on to compete successfully with F1D planes, and one is regularly on the US F1D team.

Until you can consistently post nationally competitive times, you have things with far quicker/easier payback to master.

Jeff Anderson
Livonia, MI

[calgoddard]

I attribute the torque burner arrangement described by Jeff in the prior post to Brett Sanborn, a member of the 2016 US F1D team. There are few more expert indoor fliers in the world. The only one that comes to mind is Kang Lee, the current world F1D champion.

For those unfamiliar with F1D, it is the pinnacle of indoor flying events. Effective at the beginning of 2015, F1D models must weight 1.4 grams minimum with .4 grams max rubber. They are many times larger in wing area than a 2017 WS airplane. Competitive times in the world F1D competition are typically 30 minutes plus! F1D models are typically flown in very high ceiling sites where they do not use torque burners.

I have experimented with the torque burner technique described by Jeff. I could never get it to perform on a reliable and consistent basis. I have only seen it successfully used at one WS competition - that was the 2015 SoCal State WS competition. Even then, several WS airplanes had higher flight times using the traditional no-touch flight technique. The winning time at that competition was 3:45.

BTW, torque burners are banned in some Academy of Model Aeronautics (AMA) indoor flying events.

Jeff is correct. Spend your time improving your construction, trimming and winding, and not on experimenting with torque burners.

[smrt1337]

Ok thanks! You saved me a lot of time (and pain)

[jander14indoor]

Hey, when you can consistently fly 3 minutes no touch in a 40 foot ceiling, if you KNOW you will have an important contest in a low ceiling site, you might want to remember and come back this. Otherwise, yeah, move on.

Jeff Anderson
Livonia, MI

And yes it was Brett's plane I saw and it was a true wonder. The MI tournament site at that time had only about 23 clear in the center with lights and stuff in parts of gym hanging down. His plane flew gracefully to just under rafters, descended in what looked like just an OK time almost hitting the floor before you'd hear a pop and it would climb back up again, and repeat that a second time! He did it twice at the state tournament that year and posted times that would have been competitive at nationals held and the field house in Indiana that year (I think) with a 90 ft ceiling. He probably would have won the state tournament without it with his skills, but he made it a sure thing.

[dholdgreve]

This event has "launched" (sorry for the pun) so many careers... 15 years ago, I had the honor of knowing a young man that competed for our team here in Ohio in Wright Stuff. He went on to win the Junior F1A international competition held in the salt mines of Romania... If I remember correctly He not only beat all the other junior members, but all of the adult competitors as well by like 5 minutes... The last I heard, he has about every degree you can have, and works at the Cern Hadron Collider in Geneva Switzerland...

[nxtscholar]

I had several people reach out to me on the issue of torque burners this year (apparently, the site is going to be a low ceiling from what I heard).

I'm just going to post this hear to be fair to all competitors (I think everyone who has the gall and skills to attempt it deserves all the resources and help possible). However, like others have stated, BE FOREWARNED. It is a method with a high payoff, but consequential high risk. I played around with it my senior year when I did Wright Stuff but was never able to get it right consistently and wasn't able to pursue it further being a senior. You need to invest a substantial amount of time to determine the correct position and setup for the torque burner. A SUBSTANTIAL AMOUNT OF TIME. As such, I echo the sentiments expressed by others: make sure you're already getting good times with the traditional no-touch attempts.

Now, with regards to resources, Hip Pocket Aeronautics is much more hardcore forum than scioly.org when it comes to advanced topics and ideas for model flying. Specifically for torque burners: http://www.hippocketaeronautics.com/hpa ... c=17412.75 Actually, Brett's ideas and general schematics on torque burners can be found here.

I also included a video I made highlighting the general concept up close: https://www.youtube.com/watch?v=HplWWrN-8vk
Simply put, one needs to determine the type of wire to use (thickness, pliability, etc.), the positioning of the wire, the amount of torque needed (or where to partition the twisted rubber band), and so on.

Good luck to those attempting this (you'll need it), but I reiterate, that time might be better spent towards the conventional method.