Elastic Launched Glider B

PayalParikh
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Re: Elastic Launched Glider B

Post by PayalParikh » January 21st, 2020, 9:36 pm

coachchuckaahs wrote:
January 21st, 2020, 8:59 pm
PayalParikh wrote:
January 21st, 2020, 1:16 pm
For log book, what does 10 or more test flights mean? Does it mean that we need to make atleast 10 different types of gliders to test? Or, total number of test flights, no matter how many different types of gliders we make.

Please explain us. We are new to this event.
At least 10 flights logged. They can all be with the same plane, or different planes. The intent is that you log all adjustable parameters, and you can see what changes were beneficial. So ideally you have many more than 10 flights logged, with the same plane, adjusting 1 variable at a time.

Coach Chuck
Thank you for explaining

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Re: Elastic Launched Glider B

Post by Nathanfrommars » January 25th, 2020, 11:32 am

Hi,

I tested one of our new gliders today, the hand gliding is very good. But when launching, it always flips in a circle at the top and then glides well. I checked the incidence which is ok and I don’t know what the problem is. Any thoughts?

Thanks,

Nathan

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Re: Elastic Launched Glider B

Post by coachchuckaahs » January 25th, 2020, 12:12 pm

Can you give a better description of "flips in a circle"? Which way is it going (to the top, to the bottom, to the side)

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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Re: Elastic Launched Glider B

Post by Nathanfrommars » January 25th, 2020, 2:07 pm

coachchuckaahs wrote:
January 25th, 2020, 12:12 pm
Can you give a better description of "flips in a circle"? Which way is it going (to the top, to the bottom, to the side)

Coach chuck
When it launched to top, it flipped over and down a circle vertically and then to back to glide horizontally.

Thanks,

Nathan

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Re: Elastic Launched Glider B

Post by bjt4888 » January 26th, 2020, 6:59 am

Nathanfrommars wrote:
January 25th, 2020, 2:07 pm
coachchuckaahs wrote:
January 25th, 2020, 12:12 pm
Can you give a better description of "flips in a circle"? Which way is it going (to the top, to the bottom, to the side)

Coach chuck
When it launched to top, it flipped over and down a circle vertically and then to back to glide horizontally.

Thanks,

Nathan
Nathan,

Good job measuring your incidence angles. If your glider is flipping upside down at the top of the climb, in spite of careful measurement, it’s likely that you have a little too much incidence. Other possibilities though would be something is flexing too much in effect increasing incidence during the high speed launch. Things that you do not want flexing too much would be: forward portion of the wing, “tail boom” portion of the fuselage or the stabilizer.

A looping glider can sometimes be launched successfully with extreme bank, even up to 90 degree bank. Test this gradually adding power, launch inclination angle and bank bit by bit.

Flexing parts can sometimes be corrected by adding a small amounts of carbon. If adding 1/16” wide strips of .005” carbon using thin Duco cement, sure to add to both sides of any thin wood parts as Duco cement shrinks as it dries and will cause thin wood to curve/warp if applied to only one side.

If you supply more details about your glider, I could give more specific help.

Brian T

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Re: Elastic Launched Glider B

Post by NewSciolyer » January 30th, 2020, 2:25 pm

Nathan,

Last year our glider had the same problem. If you are using a shim, try and sand it down a little and then test it. It's probably the incidence. Also, check and see if your horizontal stabilizer is warped or twisted, as that may cause it to loop.

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Re: Elastic Launched Glider B

Post by OHIOscioly » February 2nd, 2020, 10:23 pm

Help with glider that climbs too quickly? Glider works well but maybe climbs too quick? The incidence is 10 degrees and the bank is 30 degrees. Pull back 26cm. Gliders well, could transition a bit higher. I’ve never had a glider launch at such a low angle and make it right up to ceiling. 13 second flight time. Incremental launch changes lead to worse times.

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Re: Elastic Launched Glider B

Post by coachchuckaahs » February 3rd, 2020, 9:05 am

OHIOscioly wrote:
February 2nd, 2020, 10:23 pm
Help with glider that climbs too quickly? Glider works well but maybe climbs too quick? The incidence is 10 degrees and the bank is 30 degrees. Pull back 26cm. Gliders well, could transition a bit higher. I’ve never had a glider launch at such a low angle and make it right up to ceiling. 13 second flight time. Incremental launch changes lead to worse times.
That looks like a similar problem that Nathan had, and a common issue with the kits this year. If you have too much incidence (or really, decalage), then the plane will climb too much at higher speeds, or even loop. This can also be a problem if the kit was not built correctly. For example, one kit uses 1/32 sheet wings, and the center pylon is curved to induce an airfoil. If the sheet is not formed to the pylon, but glued straight, then incidence is added to make a poor airfoil fly, and the launch issue is apparent.

Of course if you take out incidence, you need to move back the CG. If it is already as rearward as you want (too much moving back makes it unstable and unpredictable), you may need to try other things.

If it is a flapper, try adding more flap (instead of incidence) by curing the flaps, but soften the flex by sanding the flaps (this works on balsa flaps, not on the Vectorboard flaps). The balsa flaps kits I have seen have flaps that are too stiff, and thus they tend to pitch up or loop on launch.

If vectorboard, try adding a bit of "flap" to the tip balsa piece. This will try to flatten at high speed, but since it is stiff, will rotate the entire leading edge slightly negative, removing the pitch up. However, in general the vectorboard flapped planes have tended to bunt, or pitch down at high speeds, in which case you need to slightly bend upward on the tip balsa pieces, in order to flex in some positive incidence at high speed.

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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Re: Elastic Launched Glider B

Post by AirplaneMan » February 7th, 2020, 7:13 am

Hi everyone,

I have the Super Protege kit and I'm having some problems with the glider when I launch it.
When I hand glide it, it flies pretty smoothly, but then when I launch it, it seems as if the left side of the glider is heavier or something because the glider goes up and then immediately the left wing dips down and the plane spirals into the ground. Not sure if I'm launching it wrong or what. Any suggestions would be greatly appreciated.

Thanks, AirplaneMan

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Re: Elastic Launched Glider B

Post by bjt4888 » February 7th, 2020, 9:27 am

AirplaneMan wrote:
February 7th, 2020, 7:13 am
Hi everyone,

I have the Super Protege kit and I'm having some problems with the glider when I launch it.
When I hand glide it, it flies pretty smoothly, but then when I launch it, it seems as if the left side of the glider is heavier or something because the glider goes up and then immediately the left wing dips down and the plane spirals into the ground. Not sure if I'm launching it wrong or what. Any suggestions would be greatly appreciated.

Thanks, AirplaneMan

AM,

It’s possible that you need to increase bank angle of launch. Also possible that there is unwanted warp or twist in the wings.

What bank and inclination angles are you currently using?

Brian T

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