Wright Stuff C

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xiangyu
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Re: Wright Stuff C

Postby xiangyu » November 12th, 2019, 7:23 am

Are you verifying the CG with the motor installed per page 14 of the instructions? Is it 1.8” forward of the wing TE? Be sure as this year’s design is extremely sensitive to CG placement. 1/8” off will cause poor flying.

Washin is the slight “wing warp” referred to on page 15 of the instructions. The inner wing relative to the circle direction should have the TE 3/16” lower than the LE. The removable shim is placed either under the bottom edge of the front of the “wing mount” wood strip and this change in placement of the shim will alternately twist the wing to washin either the right wing or the left wing. This twist or washin on the inner wing (again, relative to the circle direction) will allow the inner wing to provide enough lift to prevent rolling or diving to the floor. The correct washin is critical to achieving a decent climb.

Measure the washin by eye or by gently setting the lower wing against a flat surface and using a ruler.

Brian T
Brian, I will confirm those tonight. Been busy with school lately so haven't had a chance to get back to you.

Thanks as always for you help!

Xiangyu
2020 Events: Wright Stuff, Gravity Vehicle. Machines, Circuit Lab, Boomilever, Ping-Pong Parachute, WIDI

Inv.1/Inv.2/Reg
WS:
WIDI:
Boom:
Circuit:

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East Grand Rapids High School, Michigan

madhavaniyengar
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Re: Wright Stuff C

Postby madhavaniyengar » November 12th, 2019, 8:15 am

How big of a difference can time of day or air temperature make in a flight? Almost every time I fly, my planes change their behavior drastically, even when I don't make any actual adjustments to the plane or rubber.

bjt4888
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Re: Wright Stuff C

Postby bjt4888 » November 12th, 2019, 9:02 am

Xiangyu,

Yes, I still remember school getting in the way of my more important and creative activities (tongue in cheek).

If every other trim setting is in typical range, inner wing washin is the first possible area to investigate.

Brian T

izzanom
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Re: Wright Stuff C

Postby izzanom » November 12th, 2019, 1:02 pm

Hello everyone! About to start this season and I have some questions:
1) Has anyone tried the freedom flight kit yet? How has it performed?
2) How have people been approaching having one plane fly in both directions?

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CrayolaCrayon
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Re: Wright Stuff C

Postby CrayolaCrayon » November 12th, 2019, 1:10 pm

Hello everyone! About to start this season and I have some questions:
1) Has anyone tried the freedom flight kit yet? How has it performed?
2) How have people been approaching having one plane fly in both directions?
I haven't personally tried it, but from what I've seen people do with it, it can go in both directions and flies pretty smoothly. I've also heard good reviews about JH Aerospace.
Wright Stuff National Runner-up 2019
USA F1D Team 2020

bjt4888
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Re: Wright Stuff C

Postby bjt4888 » November 12th, 2019, 2:51 pm

We are building our own design using the Freedom Flight kit for parts. The eight FF kits my four schools are building from all have very good wood and, of course, instructions are outstanding. Inastuctions are so good (many pictures of critical steps and excellent instructions for trimming and basic aerodynamics).

Although we don’t have direct experience with it, I’m sure the J&H Aero kit is also excellent. The airplane flying in Josh’s videos looks smooth and competitive.

Brian T

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Re: Wright Stuff C

Postby bjt4888 » November 12th, 2019, 2:54 pm

...instructions are so good, a student could build successfully without experience or coaching...

coachchuckaahs
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Re: Wright Stuff C

Postby coachchuckaahs » November 12th, 2019, 3:33 pm

How big of a difference can time of day or air temperature make in a flight? Almost every time I fly, my planes change their behavior drastically, even when I don't make any actual adjustments to the plane or rubber.
Humidity more than temperature could cause warping. Small temperature changes should not matter. However, larger changes (lower) could limit the power in the rubber. Much colder though.

More likely you need to slightly increase your stability margin, by moving CG forward and re trim incidence (more incidence). Word is that this year the planes are quite sensitive to CG, so a slightly are CG could cause excessive trim sensitivity.

If you are prepared to make fine adjustments, an aft CG can be a benefit. However, with only one shot, SO planes call for a more stable trim setting. This year both flights count (bonus), so there is no room for excessive risk.

Coach Chuck
Coach, Albuquerque Area Home Schoolers Flying Events
Nationals Results:
2016 C WS 8th place
2018 B WS 2nd place
2018 C Heli Champion
2019 B ELG 3rd place
2019 C WS Champion
AMA Results: 3 AAHS members qualify for US Jr Team in F1D, 4 new youth senior records

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xiangyu
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Re: Wright Stuff C

Postby xiangyu » November 12th, 2019, 7:08 pm

Are you verifying the CG with the motor installed per page 14 of the instructions? Is it 1.8” forward of the wing TE? Be sure as this year’s design is extremely sensitive to CG placement. 1/8” off will cause poor flying.

Washin is the slight “wing warp” referred to on page 15 of the instructions. The inner wing relative to the circle direction should have the TE 3/16” lower than the LE. The removable shim is placed either under the bottom edge of the front of the “wing mount” wood strip and this change in placement of the shim will alternately twist the wing to washin either the right wing or the left wing. This twist or washin on the inner wing (again, relative to the circle direction) will allow the inner wing to provide enough lift to prevent rolling or diving to the floor. The correct washin is critical to achieving a decent climb.

Measure the washin by eye or by gently setting the lower wing against a flat surface and using a ruler.

Brian T
I believe I did all of those steps correctly. I did have the shim and the CG is in the correctly spot. I'll fly the plane again this weekend and confirm those numbers on site again, maybe I made a mistake while flying it at the gym and CG was a little off or something. If it continues not to work, I'll video it and share it with you to confirm, perhaps I simply messes up building it or something (hopefully not!).

Thanks again for all your help!
Xiangyu
2020 Events: Wright Stuff, Gravity Vehicle. Machines, Circuit Lab, Boomilever, Ping-Pong Parachute, WIDI

Inv.1/Inv.2/Reg
WS:
WIDI:
Boom:
Circuit:

Medal Count: 2
East Grand Rapids High School, Michigan

bjt4888
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Re: Wright Stuff C

Postby bjt4888 » November 12th, 2019, 7:48 pm

Xiangyu,

Sounds good. If you send more flight details it will help analysis too. Besides measured CG location, wing incidence, rudder deflection, upper and lower wing washin; also send rubber weight and loop length (length before winding), max turns, max torque, backoff turns, launch torque, circle size and propeller pitch angle (probably measured at the 1” radius, both blades).

Brian T


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