High School Student Inquiring about the Science Olympiad Event Wright Stuff

From: <thepoopgod_at_yahoo.com>
Date: 26 Jan 2016 18:14:54 -0800

Hey all,

My name is Michael Mu, I'm a senior in high school and I do the event Wright Stuff in Science Olympiad, which involves the building and testing of a rubber-powered, balsa (usually) monoplane. I was wondering if any of you could help answer some questions that have plagued me for quite a while now, after a year already of doing this event. I've already read through quite a number of the discussions in this group, so I have to say my knowledge level probably isn't very high comparatively, so forgive me if that's how it comes across!

First and foremost, I've been looking for a consistent and reliable winding approach. My brother, who did this event when he was in high school, taught me a technique called "stretch-winding," which consists of alternately winding turns while moving slowly inward and then stopping and stretching back out, and that this would help pack the most number of turns in. However, I've had trouble with this technique as it's gotten me quite a bit of variation each time I wind. So my question is, is there a better and more consistent way to wind? I've read about a common strategy which goes something like stretching out to 4x relaxed rubber length, winding about 55% of the max turns while stationary, and then winding the rest while moving in. However, how would I go about determining the max number of turns? If it is of any significance, primarily I'll be flying in low-ceiling areas (about 20' to 25').

I've also heard that as you break in a motor, you can put more winds into it and therefore get a higher time. With each successive wind, however, how would I change my winding to account for this? Would I still aim for 55%? If so, how does max turns increase, if it does, for each wind? Or is this whole process kind of just guess-and-check?

A second question that I've discussed with my brother goes like this: with each propeller + plane setup, there is a certain required torque for cruise flight. I have several propellers each set at different pitches. Would the best time potentially be derived from the propeller which requires the least amount of torque for cruise flight, provided that you have a good rubber match? Does that line of logic sound right?

Finally, (least important), what kind of rubber lube is most effective (while still being relatively cheap)? Or does this selection not matter too much?

Thanks so much for anyone's time,
-Michael Mu
 

Received on Tue Jan 26 2016 - 18:14:55 CET