Nice description, Brett - just might have to play with one
LeRoy Cordes
AMA 16974
Chicago, IL
In God We Trust
On Wed, 10 Jan 2007 12:35:41 -0500 "Brett Sanborn" <08bdsanb_at_alma.edu>
writes:
> Sorry I didn't get to this sooner.
>
> Fred's post included a lot of key information about torque burners.
> It IS a lot like having one or two partial motors on the airplane.
> Typically one or two pins are used, spaced about 1/3 or 1/4 of the
> length of the motorstick. I liked to have the first one at 1/4 from
> the front of the prop hook and the second one the same distance
> back.
>
> The flight profile of the torque burner is pretty interesting to
> watch. At State science Olympiad in 2004 my first flight did 4
> minutes without getting higher than 12'. That was the conservative
> run. The second flight did 5:01 after climbing all the way to 23'
> and coming down. With the 48cm biplanes my best torque burner time
> was 5:29 in a 21' gym.
>
> Usually the plane will climb about half the height of the gym on the
> first 'burner' then towards the end of the first burner, the plane
> will drop about 5' then climb back to the same height. When the
> second one goes off, half of the motor winds are remaining and the
> goal is to reach full height without hitting followed by a nice slow
> decent.
>
> The hardest part of playing with torque burners is probably the
> winding process. How do you get the rubber onto the wire in the
> first place? What I did was to take a piece of tubing (I used the
> stuff that I made o-rings out of, but anything like a straw will do)
> and tried my best to space it in the rubber where it would end up
> on the torque burner wire. That is to say that you place the piece
> of tubing in-between the strands of motor perpendicular to the
> rubber. Much of this requires looking at the drawing I've uploaded
> to the Files section. Typically, you stretch the rubber to the
> normal length, then work to get a feel for how far you have to reach
> so that when you're fully wound, the piece of tubing should line up
> with the piece of wire that is attached to the motorstick. Then
> simply insert the torque burner wire into the tubing and slide the
> rubber up off of the tubing. Now the wire should be in the middle
> of the two strands of rubber.
>
> As the torque decreases, a mixture of pulling and sliding happens.
> The rubber in front of the wire wants to pull forward the rest of
> the knots which are behind the wire. The rubber pulls forward, the
> wire bends slightly, and the rubber slips downward off of the wire,
> bringing more knots forward to unwind.
>
> Things you can change to affect the timing are wire diameter (
> though you'll quickly find that wire too thick or too thin results
> in a plane on the ground with 75% of winds left), wire length(same
> result usually), or the best way to change the timing is distance
> from the prop.
>
> Before actually going out and trying it, which may result in a lot
> of frustration, try just bench testing a few and recording results.
> Just take a prop and motorstick and play with and practice winding
> and hooking it up. Record times when the burner deployed and total
> prop run time. This will help build your intuition and give you a
> much better feel for how it will work on a real live model.
>
> You'll find that you can use a lot more torque and winds--much like
> a vp prop. I generally used less pitch than flying regular up and
> down flights.
>
> Feel free to ask questions, I'm not sure how well I explained most
> of it.
>
> Brett
> ----- Original Message -----
> From: soccers56
> To: Indoor_Construction_at_yahoogroups.com
> Sent: Monday, January 08, 2007 6:05 PM
> Subject: [Indoor_Construction] Torque Burners
>
>
> Hi,
>
> I'm doing the Wright Stuff for science olympiad, and our ceiling
> for
> all of the sites is pretty low. I was trying to build a torque
> burner
> to perhaps get better flight times, but i haven't had much luck
> with
> that. I can't seem to get it to work right, because it doesn't
> drop
> once the first part of the motor is used up. Does anyone have a
> picture/sketch/diagram of their torque burner, along with some
> instructions on how to use it? That would help a lot.
>
> Thanks.
>
>
>
>
>
> [Non-text portions of this message have been removed]
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
LeRoy Cordes
AMA 16974
Chicago, IL
In God We Trust
Received on Thu Jan 11 2007 - 09:08:35 CET
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