Search found 523 matches

RETURN_TO_SEARCH_ADV

by bjt4888
October 16th, 2019, 7:06 am
Forum: Wright Stuff C
Topic: Wright Stuff C
Replies: 225
Views: 11655

Re: Wright Stuff C

Eric, Sorry, I see that the textbook page is in the link you posted. I’ll have to look at your calculation for 32” of .060” later today. Prepping for first group of four students building four airplanes on Saturday. My calc using the formula for breaking turns for this rubber length and .060” (.0398...
by bjt4888
October 16th, 2019, 6:07 am
Forum: Wright Stuff C
Topic: Wright Stuff C
Replies: 225
Views: 11655

Re: Wright Stuff C

You’re missing something in application of the formula. It’s pretty accurate. The easiest way to get a good understanding of the formula is to have the textbook page that describes its use. Maybe the resource you found didn’t have a full explanation of the formula’s use. I have a .pdf of this textbo...
by bjt4888
October 15th, 2019, 7:03 am
Forum: Wright Stuff C
Topic: F1D Junior Team Selection Contest
Replies: 13
Views: 387

Re: F1D Junior Team Selection Contest

Crayola,

Great problem solving. This practice of critical thinking skills will serve you well in any field of endeavor.

Brian T
by bjt4888
October 15th, 2019, 6:41 am
Forum: Wright Stuff C
Topic: F1D Junior Team Selection Contest
Replies: 13
Views: 387

Re: F1D Junior Team Selection Contest

Crayola, Thanks much. Bye the way, great job to you too! Pretty exciting finish. Do you have plans to find the additional 4 minutes per flight (or more) that it will likely take to win at the World Championships? Maybe you already have this much capability in the higher ceilings at the salt mine. Br...
by bjt4888
October 15th, 2019, 6:35 am
Forum: Wright Stuff C
Topic: Wright Stuff C
Replies: 225
Views: 11655

Re: Wright Stuff C

Eric,

Your on the right track for max turns and max torque.

There are a number of threads in Hip Pocket that discuss motor winding, max turns and torque calculation, etc. Look in the sections for the lighter duration classes like F1D, EZB and even Penny Plane.

Brian T
by bjt4888
October 15th, 2019, 6:25 am
Forum: Wright Stuff C
Topic: F1D Junior Team Selection Contest
Replies: 13
Views: 387

Re: F1D Junior Team Selection Contest

Chuck, Congrats to you team for super results. Your students will represent the US well at the Worlds. The salt mine flying should be another special experience. A tremendous effort to build, test and compete the F1D’s! Remind the forum (and me) the ceiling height at the team selection site (Lakehur...
by bjt4888
October 14th, 2019, 5:43 am
Forum: Wright Stuff C
Topic: Wright Stuff C
Replies: 225
Views: 11655

Re: Wright Stuff C

Eric, If your 32” motor is 2.9 grams with two rubber o-rings, then the rubber weight would be 2.9-.09=2.81. The rubber length would be 32*2=64+.25=64.25 (counting the .25” approx in the knot) and the density would be .0437 g/in. Using .083 g/in as a standard for 1/8” rubber strip (this used to be ty...
by bjt4888
October 14th, 2019, 4:53 am
Forum: Wright Stuff C
Topic: Wright Stuff C
Replies: 225
Views: 11655

Re: Wright Stuff C

The formula for projected maximum turns for a particular length and density motor that we use is a variant of John Barker’s. His formula, and interesting discussion about it, is posted in Hip Pocket Aero.

Brian T
by bjt4888
October 14th, 2019, 4:51 am
Forum: Wright Stuff C
Topic: Wright Stuff C
Replies: 225
Views: 11655

Re: Wright Stuff C

Xiangyu, As for possible improvements in flight duration under a 30 ft ceiling, there are many variables to test. Matching rubber to propeller, propeller design, propeller pitch and learning to wind close to 90% of breaking turns are a few of the most important. Actual projections of flight time I n...
by bjt4888
October 13th, 2019, 7:25 pm
Forum: Wright Stuff C
Topic: Wright Stuff C
Replies: 225
Views: 11655

Re: Wright Stuff C

“Non destructive break in not “breaking”. Bad autocorrect.

RETURN_TO_SEARCH_ADV