Elastic Launched Gliders B

[builderguy135]

I think it's my flaps that are flexing, but that's what's supposed to happen. My wing right now has no undercamber either, it's just mounted on flat fuselage with no pylon.

Where can I get the carbon fiber?

[Kai0721]

I think it's my flaps that are flexing, but that's what's supposed to happen. My wing right now has no undercamber either, it's just mounted on flat fuselage with no pylon.

Where can I get the carbon fiber?

You can get carbon fiber from the freedom flight website. It’s under the parts tab.

[builderguy135]

I think it's my flaps that are flexing, but that's what's supposed to happen. My wing right now has no undercamber either, it's just mounted on flat fuselage with no pylon.

Where can I get the carbon fiber?

You can get carbon fiber from the freedom flight website. It’s under the parts tab.

Wouldn't I need a CF sheet for this or would the tow work fine to add stiffness to the wing?

[bjt4888]

Builder,

1k carbon tow is adequate to add stiffness to the wing. FF sells 3k carbon tow. 1k weighs .005g/in if applied carefully with three coats of thinned duco. 3k weighs about .011 g/ in sing the same application method (too heavy, and stiffer than necessary. See “CST The Composites Store” for 1k tow.

See these threads for pictures and descriptions of gliders with carbon added to the wing and fuselage:

http://www.hippocketaeronautics.com/hpa ... ic=16656.0

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

Brian T

[Maxout]

If you're looking to reinforce a balsa fuselage with carbon, I find carbon rods much easier to use than tow. Many of the methods on display for ELG are really overcomplicated. CAing some .010 rods (top bottom and sides, for a total of 4) onto the fuselage will make it incredibly stiff. The best solution is just to make a fuse from either .050" carbon rod or .059" carbon tube. It's indestructible in standard ELG usage. http://www.cstsales.com/carbon_rods.html

For reinforcing the wings, consider the .005" carbon strips from CST: http://www.cstsales.com/Carbon_Fiber_Strips.html

If you're having trouble reaching the ceiling, push the glider harder. If it isn't fluttering, you're not in danger of breaking things. Here's an example of a VERY heavily sanded Super Protege climbing to nearly 35'. I could have launched even higher but was concentrating on launch consistency.
https://www.youtube.com/watch?v=KJ9YR4Il2WU

[AirplaneMan]

I tried increasing the incidence a lot and I had to also add more clay to compensate for that. But this same situation seems to occur. The glider goes up and then immediately flies towards the ground. What I mean by that is that the glider goes up, then after reaching its maximum height, it slightly turns to the left and flies downwards at a 45 degree angle. It doesn't dive at a 90 degree angle; it's almost as if it's a glide, but the glider loses altitude very quickly and hits the ground.

Airplaneman-
Gliders are tougher to trim then Wright Stuff. See my list below-

If the glider ROLLS Left, points its nose down, then the left (Port) wing needs more positive incidence. That is, the leading edge needs to be higher than the right (Starboard) wing.

1) Technique #1, Turn model upside down and bend the port wing's leading edge up a couple of degrees. It the wing cracks, drop some CA in the crack.

2) Technique #2, crack the port wing's wing root at the leading edge and lift it a degree and glue in place.

3) If the glider enters transition, note if the orbit is left or right. I suspect a left hand orbit. If the glider is stalling, add clay to reduce the stall.

4) If the glider has a slight diving flight, remove some clay.

Report on these changes and I can offer more suggestions.

Regards,
50 Missions

Thanks for the tips!
But the wing has carbon fiber glued on so wouldn't cracking the wing mess that up?
Plus I'm a little hesitant to break the wing that I spent so long making... Isn't there anything else that I could do?
Anyway, I increased the incidence by a pretty good amount (~1 degree) and I also increased the weight on the nose, and the same situation seems to persist, but it isn't as bad. Before, the glider would be flying downward (as stated in the posts above) but now, this only happens for the beginning of the flight. For example, I launched the glider to about 20-25 feet and in the first 8-10 feet the glider was still flying downward. Then, it leveled out and began gliding like normal. How can I stop the glider from doing this? I'm losing all that altitude because of that fast downward glide in the beginning and that is giving me lower times (~10-15 second flights)

[builderguy135]

Builder,

1k carbon tow is adequate to add stiffness to the wing. FF sells 3k carbon tow. 1k weighs .005g/in if applied carefully with three coats of thinned duco. 3k weighs about .011 g/ in sing the same application method (too heavy, and stiffer than necessary. See “CST The Composites Store” for 1k tow.

See these threads for pictures and descriptions of gliders with carbon added to the wing and fuselage:

http://www.hippocketaeronautics.com/hpa ... ic=16656.0

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

Brian T

If I increase the chord length of this plane from 3 to 4 inches (increasing the wood area not the foam area) where would the new high point of the aerofoil be?

[bjt4888]

Builderguy,

High point of airfoil is 25% of wing chord. So, on a 4” chord at wing center, 1” back of leading edge at wing center. Congrats working on customizing the design. With a wider chord, might want to add 1” to the nose to make it easier to balance with minimal clay. Keep the distance between the wing TE and stab LE unchanged and kee the stab area at about 14% or 15% of wing area. Keep fin height (and area) the same if wing dihedral height remains 1.25” each side (recommended).

Brian T

[Saiguy7]

I bought the Freedom Flight model for my glider and spent a lot of time following the directions- sanding the wings, doing the carbon fiber, making the airfoil, flaps, etc. I was trimming it for a long time but there is one problem that seems to persist: the glider launches up, but never transitions into the slow glide. Instead, it just launches up and quickly spirals down, losing a whole bunch of altitude. The glider completed half a counter-clockwise turn and flew for just a couple of seconds. It is banked to the left (maybe around 40-60 degrees) and angled up at 40-60 degrees.

[fifty_missions]

I think it's my flaps that are flexing, but that's what's supposed to happen. My wing right now has no undercamber either, it's just mounted on flat fuselage with no pylon.

When you launch does the glider make a slight buzzing sound? If it does, that is FLUTTER. That is Drag to the max and whatever height you got, that is all you will ever get with that.
glider.

It seems counter intuitive but John Hance's (GuRu Glider) suggestion to apply a good cellophane tape along the root of the flapper section will both reduce cracking and Flutter. The worse that can happen is the flap's flex is slightly reduced and the glider climbs is a "BUNT" trajectory. This is not bad just odd to see. The glider may make a curve (nose coming down) path during the vertical high-speed launch. It should slow down and settle into a level glide at the apex.

Send me a video. and email me a head-on, side and top view of the glider.
http://www.sandmanoverhaulplus@gmail.com

BTW, the top three finishers in the Indiana State Competition last Saturday all had my coaching and used my designs.

Good Luck,
50 Missions