Elastic Launched Gliders B

retired1
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Re: Elastic Launched Gliders B

Postby retired1 » November 14th, 2018, 10:13 am

The rudder is more effective at higher speeds, so it may be losing effectiveness If that is the case, it should not take a full circle to start going straight as it slows down. If you are using a left circle, try wetting the fuselage a bit and twisting it to lower the right portion of the horizontal stabilizer. If you are using a right hand circle, make the left stab tip a bit lower. Actually you are moving the entire stab, but it is easier to measure/reference the tip.
this pulls the tail to the outside of the circle so the nose turns to the inside of the circle.

waffletree
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Re: Elastic Launched Gliders B

Postby waffletree » November 14th, 2018, 10:14 am

I will try that as soon as I get the chance. Thanks!
builder cult vp // #treegang

Hartman
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Re: Elastic Launched Gliders B

Postby Hartman » November 22nd, 2018, 2:50 pm

My plane keeps on flipping over and nose-diving whenever I launch it, and at first, I thought that my flaps weren't level, but when I leveled them, it continued to do barrel rolls. Need help, please advise

bjt4888
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Re: Elastic Launched Gliders B

Postby bjt4888 » November 22nd, 2018, 6:27 pm

Hartman,

Possibly your flaps are not equal in stiffness. You can test this by placing a small weight in the same location on each flap (one flap at a time) and measuring how much each flap deflects.

Describe your glider design and launch in more detail and I would be better able to help.

Brian T

Hartman
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Re: Elastic Launched Gliders B

Postby Hartman » November 25th, 2018, 6:02 pm

Thank you! I will test this as soon as I can.

coachchuckaahs
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Re: Elastic Launched Gliders B

Postby coachchuckaahs » November 26th, 2018, 7:16 am

We had a similar problem with one glider. We played with flaps for awhile, but did not find the issue. Finally we put a different wing on the fuselage (taped on), and it did the same thing, while that wing was fine on its own fuse. Therefore, we cut the stab off and put on a new stab and fin, problem gone.

Whatever was not straight was subtle. Small errors on the tail group can cause big issues.

I would certainly look at flaps for differential flex, and look for wing warp. But if you have more than one plane (you should), try mix/match parts for diagnostic reasons.

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

WafflesareReal
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Re: Elastic Launched Gliders B

Postby WafflesareReal » December 3rd, 2018, 2:54 pm

My glider keeps turning when I do not want it to. Please help me.

Thanks.

bjt4888
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Re: Elastic Launched Gliders B

Postby bjt4888 » December 3rd, 2018, 3:14 pm

Waffles,

Unwanted turn can come from a number of sources, including: rudder offset, one wing heavier than the other, warped wings, warped fuselage, stabilizer tilt, etc.

Please describe your glider in detail (ex. Kit or from a particular published plan, or self designed 1/16” sheet rectangular 3” width wing with 15” x 3/32” thick x 1/4” deep tapered to 1/8” at the tail fuselage and ... dimensions for the stabilizer and rudder, and weighs...grams).

Also please describe the turn. Is it hooking on launch? Turning too tight of a circle in glide?

Also please describe your launch device and launch details (ex. Launcher 6” x 3/16” wood dowel with 6” loop of tan sis rubber; launched at 45 degree angle with 10 degrees of bank in a 25 ft. Ceiling site and launched to about 20 ft.).

With this info, I can provide some specific suggestions.

Brian T
AMA since 1968

falcon1236912
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Re: Elastic Launched Gliders B

Postby falcon1236912 » December 4th, 2018, 7:03 am

What times have people been getting with the FF kit?

bjt4888
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Re: Elastic Launched Gliders B

Postby bjt4888 » December 4th, 2018, 9:31 am

Falcon,

As the FF kit is very similar to gliders that my students built for Division C in 2013 and 2014, and as the wing loading is very similar in this year’s rules as compared to 2014 (this year = .125 g/square inch of projected wing area vs. 2014 = .115 g/sq in), the FF glider should be capable of 1.1 to 1.15 seconds of duration for each foot of launch altitude if built accurately to minimum weight of 3.5 grams and trimmed to transition without loss of altitude.

My and 2014 students flew 27.5 - 28.5 seconds at a launch height of 25 ft (their gym ceiling was 27 ft). Based upon past results, these flight times should probably be competitive to win at any State Championship and at Nationals.

Brian T


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