Wright Stuff B

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GitItWright
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Re: Wright Stuff B

Post by GitItWright »

Roll Issue- Wright Stuff

StampingKid-

There are a few reasons why the roll happens and carneyF1d covered some of these.

For lack of and engineer's techno speak, it pretty much boils down to countering a "mechanical" issue with an "aerodynamic" fix.

The roll begins with Newton's Third law, for every action there's an equal and opposite reaction. On launch the airplane is reacting first to the high torque of the motor pushing the airplane in the opposite direction that the prop is spinning. Much could be due to the high torque being transmitted through the motorstick and twisting it along its axis. This causes multiple and "infinitely" changing variables to the flying surfaces.

Most notable is that the left and right wings twist in opposite directions. Try it and see the difference yourself. Set up an airplane and twist the nose left and the aft end right. If the left wing's leading edge is lower than the trailing edge, that wing reduces lift. If the right is opposite, with the leading edge higher than the trailing edge, then it has more lift. This whole combination will cause the airplane to roll left (counter-clockwise looking from the tail forward) and even dive.

The aerodynamic fixes- can include the following-
1) Break and raise the left wing's leading edge for more incidence (higher angle of attack) in comparison to the left trailing edge. re-glue the new setting
This, aerodymanically, increases lift to counter the mechanical forces of the high torque motor.
2) Offset the wing to the left so that more wing area is left of the centerline (the motorstick in this case) usually this is a built-in feature of locating the wing posts so that the wing is offset.
3) Confirm the twist in the motorstick and build a stiffer one. This issue was covered thoroughly during the season and probably showed up as a "bowing motorsticks" thread.
4) If the airplane is overweight (ie: 8 grams or more), it takes larger motors and even more torque effecting the motorstick twist. Keep the airplane light but make sure the motorstick is a reasonale cross section 1/4 x 3/8 is a good starting airplane weight close to 7 grams.

Good Luck
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Re: Wright Stuff B

Post by carneyf1d »

Anybody know when the draft rules come out?
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Re: Wright Stuff B

Post by fmtiger124 »

carneyf1d wrote:Anybody know when the draft rules come out?
not for a while id guess
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Re: Wright Stuff B

Post by smartkid222 »

i don't think they are going to have draft rules this year. They posted the tentative event names and i think the actual rules coming out in september are next.

Carney, i think you posted a link before to show us a helicopter, but it linked to an album and i didn't see any helicopters there. Do you (or anyone) have a picture of a helicopter discussed in the flight trio thread?
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Re: Wright Stuff B

Post by blue cobra »

jander14indoor,

Many, many posts back, I think on page 24, you mentioned using 8# balsa for wing posts. Is this really dense enough? Especially with hot and humid conditions often present in the gym.
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Re: Wright Stuff B

Post by karatekid44 »

I would ahve to think so
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Re: Wright Stuff B

Post by jander14indoor »

blue cobra wrote:jander14indoor,

Many, many posts back, I think on page 24, you mentioned using 8# balsa for wing posts. Is this really dense enough? Especially with hot and humid conditions often present in the gym.
Probably strong enough if your plane is light. Certainly as you become more experienced and have less crashes. But with the generous weight budget for Wright Stuff, you can probably go to 12 lb/ft3 wood and still meet the 7.0 gm target. You'll have to save weight someplace else. On my plane this year, I used 8 lb wood to hit target with tissue and grocery bag covering. With indoor film I could go to 12 lb/ft3 wood and hit target.

Wing posts seem to break more often from handling, poor execution, and over weight planes adding more stress during a crash than anything else. No density will help that, even oak would break if your hands go in different directions. Breaking in normal flight is bad wood selection, or poor build execution.
carneyf1d wrote:Anybody know when the draft rules come out?
Probably won't be any published. I'd expect draft rules to be shared at the summer coaches clinic, but they are just that, draft. Frankly, build 7.0 gm planes to this years rules, practice and trim aiming at 2:30 to 3:00 flights and you will be more than prepared for any changes the new rules throw at you.
StampingKid wrote:Speaking of the history of our discussions, can we count on this remaining an active board as long as Wright Stuff is an event? I think I would have a panic attack if I woke one morning to find it gone. I have cut and pasted some discussions in the past for future reference but as the discussion progresses more becomes relevant.
Unless I and several others are dead and in the grave (and probably even then, if there's an ethernet, maybe there's an aethernet...), there will be some forum, somewhere discussing this event and offering help over the internet.

I hope it stays here, the hosts run a nice forum, thank you. Though it'd be nice to have a dedicated sub-topic for WS, maybe Elevated Bridges too. That thread is even longer than this one! Make it easier to search or follow the many separate threads that come up.

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Re: Wright Stuff B

Post by karatekid44 »

do you have to do that
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Don't put the stick there! Thats what she said!
Ah Science Olympiad give perfect opportunities for thats what she said jokes.
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Re: Wright Stuff B

Post by 49ers »

thank you guys for the advice
carneyf1d said: <snip> they[carbon blades] are pretty cheap.<snip>
gh said: <snip>I recommend you get a box of 50 single edged razor blades maybe $10 to $20.<snip>
Last edited by 49ers on June 19th, 2009, 4:24 pm, edited 1 time in total.
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Re: Wright Stuff B

Post by karatekid44 »

awesome advice
My Brother USCGA-2012
I'm On A Boat
The Bloodhound Gang
Don't put the stick there! Thats what she said!
Ah Science Olympiad give perfect opportunities for thats what she said jokes.
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