Flight Times

hogger
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Re: Flight Times

Post by hogger » February 21st, 2017, 1:16 pm

JasperKota wrote:I've been getting around 1:40 pretty consistently, though its max height is around 15 feet so there's still room to climb. Planning on building/buying a torque meter, as well as getting more rubber so I don't have to worry about conserving :ugeek:
It has been a long time but there is this trick that I recall with using partial motor to deal with practicing with a lower ceiling than the ceiling at the real competition.

The idea is to build a balsa stick with hooks at both ends and attach it to the tail hook of the plane on one end while the wound motor on the other. The stick should be light and about the same weight as the rubber per unit length. So for example, if your practice height is 15 feet and the competition venue height is 30 feet, you can build a stick of about half the length of the span of the normal motor length. You would shorten your normal motor by half and wind it to the max and trim your plane for your 15 feet height for best time. When finally, you are at the competition venue, you no longer use the stick, and you double the length of the motor back to normal and wind it twice as many as your practice winding. This way you can trim your plane properly for the 15 feet height while at the same time, your trim should be very close to your best for 30 feet height ceiling with regular length motor.

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Re: Flight Times

Post by jander14indoor » February 22nd, 2017, 3:54 am

Called "Partial Motor Testing". Correct except for a few refinements.
The stick MUST weigh the same as the rubber it is replacing.
s length is not based on the rubber length, but the hook to hook length.
Half motor testing as you describe requires a stick half the max rubber weight and half the distance from hook to hook.
Quarter motor testing would require a stick 3/4 the hook to hook distance and weigh 3/4 the max rubber. Full motor flights then require 4 times the winds and 4 times the heights.

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Re: Flight Times

Post by calgoddard » February 22nd, 2017, 8:28 am

I agree that partial motor testing is a good way to prepare for a contest at a venue with flying height A where you can only practice in a flying venue with flying height 1/2 A, for example.

In order to get the maximum benefit from this technique, you should fly using a torque meter and record your results.

I have a word of caution, however, regarding partial motor flights. If your model has some peculiar flight characteristics under high torque, be aware that those characteristics will last twice as long with a full motor as they do with a half motor, wound to the same launch torque. For example, if your motor stick bends at 0.30 inch-ounces of launch torque, it may not hit the ground launched with a half motor wound to that torque, but it may hit the ground launched with a full motor wound to that same torque. This is because the induced positive stab incidence will last twice as long.

Similarly, the stab tilt and wash-in of your model may change at high launch torque due to motor stick twisting. The resulting change in flight behavior of your model will last twice as long flying with a full motor wound to a specific launch torque in contrast to a half motor wound to the same launch torque.

I warn about these phenomena because indoor fliers often determine that they need to increase their launch torque to fly in a 40 foot high ceiling, after they have been flying in a venue with a 20 foot high ceiling.

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Re: Flight Times

Post by JasperKota » February 22nd, 2017, 5:32 pm

Thank you for the very informative responses, although I meant that my plane was flying around 15 feet, and that I wished to make it climb higher. I still plan to do some research on partial motor flights though, for when I don't have access to the school gym. The plane is also landing with a fair amount of winds left, around 100-150. I think 1:30 should be enough to win regionals, which is coming up shortly, but I'd still like to improve my times before then.

Sorry if it's a dumb question, but if the goal is to get the rubber to as many winds as possible without breaking, how would dewinding help? Say the rubber breaks at where the torque meter reads .65 in-oz, so you wind to about .60 in-oz. If you wind more, you risk breaking the rubber, but if you dewind in this case the torque goes down and you get less winds.
Last edited by JasperKota on February 23rd, 2017, 1:34 pm, edited 1 time in total.
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Re: Flight Times

Post by jander14indoor » February 22nd, 2017, 7:01 pm

For a well trimmed plane in a low site (say less than 50+ feet) max torque will probably drive you into the ceiling with the proper prop/rubber match, if the ceiling is at all cluttered you WILL get caught. To stay out of the ceiling (no touch flights) you need to wind to a torque that just gets you to the ceiling. To have max turns at that torque, you'll need to wind past their and unwind back to it. It will take fewer turns to wind back than it took you to wind past. See my experiment discussion on winding in other threads. Do it and graph it. It will make more sense then.

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Re: Flight Times

Post by JasperKota » April 8th, 2017, 6:33 pm

Winning wright stuff time at New York States was a minute forty. Second place 1:39. Ceiling had some low hanging lights, however. There were a couple teams who were able to get just about two minutes during test flights.
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Re: Flight Times

Post by bernard » April 8th, 2017, 9:09 pm

JasperKota wrote:Winning wright stuff time at New York States was a minute forty. Second place 1:39. Ceiling had some low hanging lights, however. There were a couple teams who were able to get just about two minutes during test flights.
Congratulations, Jasper!
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Re: Flight Times

Post by freed2003 » April 8th, 2017, 9:11 pm

I got 1:35 (also had the bonus) and got 11th at socal, just saying as a statistic
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Re: Flight Times

Post by JasperKota » April 9th, 2017, 6:59 am

bernard wrote: Congratulations, Jasper!
Thanks bernard! Also thanks to those who answered my questions on the forums, and gave advice. I ended up placing 2nd in the event :)
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