Elastic Launched Gliders B

[windu34]

Elastic Launched Glider B: Prior to the tournament teams design, construct, and test elastic launched gliders to achieve the maximum time aloft.

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Past Threads: 2012, 2013, 2014, 2015, 2016

[retired1]

Freedom Flight and Guru both shipped planes and gliders today. Ward scientific did not have an available kit as of yesterday.

[OHscioly]

Guru gliders are a great value and John Hance is very helpful and knowledgeable. 4 kits for half the price of freedom flight has made it the go to choice for the team I coach. Freedom flight makes a good plane obviously but the directions have been too complicated for my students and we go through planes quickly so it was eating up the budget.

The 3 junior highs in my area worked with John Hance on Wright Stuff last year and one team medaled and we got 10th at states.

[retired1]

I have both the guru and the freedom flight glider kits. Both build 4 gliders. The guru glider built at 4.18 g The freedom flight will build at the 3.5 g.

For beginners, I think that the guru kit would be the better choice as it is half price and will build in a couple of hours. I doubt that a stock build would be in the top 5 at state. The freedom flight glider is a better design for the serious competitor . The sanding will take over an hour for each half wing. My first one was over 2 hours with frequent measurements and weights. You have to read the instructions very well before and during build. This glider will very probably have most of the top 5 places at state.

John from Guru gave me some ideas for making his bird lighter which will make it fly longer.

Guru has a launcher for $25 and freedom flight has one for for $18 plus $1 for a yardstick.. the guru is a bit harder to use, but will very probably be a tiny bit more accurate.
Having broken the first Guru wing with the stick launcher, I strongly recommend either one of these. Repeat ability goes way up. Breakage will go down.

I think that teams should look at the offerings from J & H Aeronautics. Their catalog is a bit deceptive as it is rather long. Their simple glider is very similar to the Guru one and their best one is very similar to the freedom flight glider.(foam flaps) Possibly a bit less sanding. The build video is not out yet for this one.

If you are rich, you can always go with Wards. Their kit is not out yet and their description of it is far from complete or correct. They told me that the updated information will be out shortly. That was 10 days ago and it is still not out.

[NewFlyer20002]

One set of gliders we built has this flutter sound which we deduce are the wings "flapping" during launch. Any suggestions on how to prevent this from happening? Are the wings too stiff or too flexible?

Regards,
NewFlyer

[retired1]

The flutter that you hear is very bad for the wings. To get an idea of flutter look at a flag in a 15 mph wind.
One solution is to slow the launch speed down, which is not good as you will not get the desired altitude. Making the wing stiffer will reduce it some, but that adds weight which is also not good. Look up "flapper" gliders for another option. The thin flap area bends back to reduce camber during the high speed portion and then returns to normal camber for the glide portion of the flight.. Several builders have used glued on carbon fiber tape which really helps. For this, take a look at hip pocket gliders by ol bill, mainly his WIF 5 The site is free, but you must register.

[NewFlyer20002]

Retired1,
Thank you for the reply.
NewFlyer

[bjt4888]

New flyer,

What thickness and density wood are you using for your wings? Also, what are you wing dimensions and shape (ex. 3” chord and 12” projected span, Rectangular, tapered, semi elliptical, etc.). Balsa wings, I assume. What height ceiling are you launching to? What decalage angle are you using (difference between the stabilizer incidence and wing incidence angle? And, finally, what method are you using to attach the wing to the fuselage (ex. Full chord of wing directly glued to fuse, attached to a partial chord pylon that is taped to fuse, etc.).

Brian T
AMA since 1968

[waffletree]

Hi, I'm having an issue with my glider turning...
My glider goes in a circle for the first circle around the gym, however, on the second circle, it ends up going straight and crashing into a wall. Does anyone else have the same problem or knows how to fix this?
Thanks

[isotelus]

Perhaps increase tilt of stab or turn of rudder? Sounds like it isn't turning enough.