Raw Tournament Times

someusername
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Re: Raw Tournament Times

Post by someusername »

bjt4888 wrote:someusername,
Sorry, I was typing too fast earlier today. Backoff winds when 1/2 motor testing should be approximately halved just like maximum turns are halved. I made a mistake in the post above indicating backoff turns for a full wind. For a first 1/2 motor test flight wound to 750 - 780 turns, a backoff of about 45 turns should give you a launch torque of .5 in oz. If this flight is safe, then you could increment torque up by backing off less on the 2nd and subsequent flights (ex. same max turns and backoff 30 and, if still safe flying character and under 28 ft. total altitude, try backoff of 15 or 20). I addition to determining the torque and winding strategy that will carry you to 1/2 the height of the 65 ft. Nationals site (probably want to shoot for 50 or 55 ft to be safe), 1/2 motor testing will demonstrate if your airframe can handle high torque. As torque is increased, your airplane will probably bank a fair amount in the first circle or two. This is ok as long as the bank doesn't cause the airplane to roll to the floor. It's not even a problem if the airplane descends in the first 1/2 circle or so and then starts climbing, although this is not ideal for a 65 ft site for this type of airplane.

Another article you could read about partial motor testing is in Indoor News & Views issue #120 (F1L Issue). It's easy to find on the web.

Good luck,

Brian T.
Thank you very much for all the input, it has really helped clear a lot of things up and showed me some new testing strategies

Regarding the previous post, I am aware I have incidence angles (sorry if I worded that badly), but I have no good way of measuring them.

Also, how do you get so many winds on those motors? I have wound up 0.094 motors to the breaking point before (never tested before) and they all broke at about 1500-1700 (they were all at 2.0g) and the last time I tried to get a 0.081 over 2000 it snapped at 2100, just before I started to backoff. Any thoughts on this? Am I winding them wrong?

But I will definitely try out the half motor testing, that should help out a fair amount I hope, or at the very least help me understand the event more. I have not had an issue with the rolling much this year, partly because I launch the plane with a slight bank to the right, which almost always cancels out the roll or gives the plane enough time to recover from a bad one.
simplicity is key...sometimes
bjt4888
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Re: Raw Tournament Times

Post by bjt4888 »

someusername,
To get the most winds possible into a motor consider the following:

Lubricate before tying knots and use the "two overhand knots" method described in this forum (there are pictures with a step-by-step of this knot tying on the Hip Pocket Aeronautics website in the "indoor free flight forum/general discussion/page 1/thread title "winders, winding stooge, torque meters/... third post by OlBill "Making a Rubber Motor"). This knot tying method is the least likely to abrade the rubber as you tie. Make your motors as long as possible. 1.98 grams would be good. Even a little lighter, like 1.95 is giving up 1/4" of motor size. Longer motors will take more turns. Weigh and measure every motor you make and record this data. Lubricate by spraying Armor All in a zip-lock bag (about 4 squirts), dropping the motor in and massaging lube in for about 10 seconds. Drop the motor out of the bag onto a clean paper towel and fold the towel over on it and pat once lightly. The end result is a motor that is not dripping lube, but is thoroughly coated and very wet and shiny looking. Stretch to at least 6 ft. on the .094" motor and at least 8 ft. on the .081" motor and wind the first time to about 80% of planned max winds. When winding, put about 50% to 60% of turns in at full stretch and walk in slowly while putting on remaining turns. The objective is to finish winding exactly as the motor is the length it will be when it is installed in the airplane. Do not finish walking in to this motor length and then put more turns on and do not finish winding when still far from the torque meter and then walk in while not winding. Then let the motor unwind and rest about 10 minutes after this first winding. The motor is now ready for competition or for a test wind to 1,575 for .094" and 2,400 for .081". All motors should be wound exactly once to break them in prior to competition. My students arrived at the ES desk with five motors prepared and prewound once, three motors at 1.99 - 1.98 grams and two at 1.94 (in case the ES scale weighs the 1.98 gram motor as overweight).

A motor prepared this way should take max turns easily. Your .094" motors with two black rubber O-rings on them should be at least 15" long or slightly more. Your .081" motors should be over 20". This is very important.

Brian T.
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