Elastic Launched Gliders B

[WMSSO2018-2019]

Thank you for getting back so quickly. Now I know alignment can play a big part. But every thing is symmetrical. Even before I glued the wings together I measured their weights to make sure that they were equal and they were. If hooking is the problem how can I solve it? Also before gluing I made sure that each Wing looks like a mirror image of itself. The ceiling height is around 25 to 30 ft. Our launch angle is 35°. Then we tilt our wings to the right at about a 35 to 40 degree angle. So when it gets to the top of the building, the plane will ree correct itself show it starts going to the left. But when it gets going towards left it starts to go downwards and then as it gets about 12 to 15 ft in the air it starts doing its perfect circles like it is supposed to. Thank you for your advice this will help us a great deal. What would you consider a good time.

[bjt4888]

WMS,

You answered question 5 and 6 from my list above. Please answer the other questions and then I will be able to help.

Brian T

[Hartman]

To increase the height that my glider reaches, should I increase the pull-back, inclination angle up, or some combination of both? Also, I've been testing with more pull-back, and it seems that I need to move my bank angle to the right as I pull back more. Is this what some of you have been experiencing as well?

[bjt4888]

Hartman,

See reply #4 in this forum that I wrote in 2014 with regards to the relationship between bank, inclination and amount of elastic stretch:

http://www.hippocketaeronautics.com/hpa ... ic=16492.0

Good job posting a specific question on the wiki.

Brian T

[bjt4888]

Hartman,

A little more info related to your question. You will see in the Hip Pocket Aero post in the link above that the best way to find the optimal bank angle, inclination angle and rubber stretch is to follow progressive steps in initial launches. If, after following this progressive approach, it appears that a moderate inclination angle and a safe and somewhat successful bank angle still do not produce a transition from climb to glide with zero loss of altitude, then you can decide to try steeper launch angles with the same bank angle as previous flights (if they are somewhat successful). Steep inclination angles can be a little risky as a “hammer head” stall (this is a term for an extreme stall), followed by a steep dive and crash is possible. When launching steeper, you’ll need to reduce rubber stretch somewhat as the distance to the ceiling is now shorter.

If you are flying a proven design, and it is built accurately (yes, at launch speed an unintended 1/32” of wing washin, or the same small amount of unintended twist in the stab, will cause poor flying), of proper stiffness and lightweight wood, should transition from a full power launch with a “flop to the side” combination of roll and yaw (look up these Aero terms if you don’t already know them), with zero loss of altitude. Proper stiffness of wood parts (very stiff fuselage, fin and stab, and reasonably stiff wing) and light weight (low 4 grams or better) are very important to achieve good transition.

Brian T

[AdiMohapatra77]

Hi, does anyone have the instructions for the 2019 Guru elastic launched glider plane kit? Also, does anyone have instructions for the Guru glider launcher?

[waffletree]

Hi, does anyone have the instructions for the 2019 Guru elastic launched glider plane kit? Also, does anyone have instructions for the Guru glider launcher?

On their website, there are videos that need a password which should have been in the box that was shipped to you.

[Hartman]

Thank you Brian! I tried increasing both at the same time, and what I'm finding is for every one inch of extra pullback, you want around 10 degrees up, and maybe around 10 degrees to the right.

But now I'm having more difficulties . Somehow, my glider is changing even though I'm just leaving it in the box, not even touching the glider. Also, now when I launch, my transition is fine, and my turning is fine, but then after it turns about 180 degrees, it suddenly falls down fast, and I was noticing that my glider had the tendency to have the left wing tilted towards the ground while falling. I changed my bank angle to the right more, changed left flap foam deflection downwards more, and also tried less rudder deflection, but none of them seemed to be working. Another thing I've tried is putting some clay on my right wing to counter-act the tilting, but that didn't work either.

[builderguy135]

Thank you Brian! I tried increasing both at the same time, and what I'm finding is for every one inch of extra pullback, you want around 10 degrees up, and maybe around 10 degrees to the right.

But now I'm having more difficulties . Somehow, my glider is changing even though I'm just leaving it in the box, not even touching the glider. Also, now when I launch, my transition is fine, and my turning is fine, but then after it turns about 180 degrees, it suddenly falls down fast, and I was noticing that my glider had the tendency to have the left wing tilted towards the ground while falling. I changed my bank angle to the right more, changed left flap foam deflection downwards more, and also tried less rudder deflection, but none of them seemed to be working. Another thing I've tried is putting some clay on my right wing to counter-act the tilting, but that didn't work either.

I think the problem is your horizontal stabilizer. Try tilting it less/more.

[bjt4888]

Hartman,

Describe your glider design in detail (all measurements and trim settings) and I can help better. See some of my previous posts in this thread for the questions that I would need you to answer about your glider.

Glider appears to be a simpler event than Wright Stuff, but it isn’t. The tiniest details matter because of the high launch speed and the challenge of transitioning to the slow circling glide.

Brian T