Elastic Launched Gliders B

[Maxout]

Can anyone reach out to me if they know any ideas on how to help gliders have a smooth transition? Currently, my glider just comes back down immediately without transitioning. Any other tips are welcome.

If it's diving all the way to the floor, add up elevator. Otherwise it's an issue of rudder trim and wing wash. Here's a trimming guide that's applicable to any flapped glider: https://www.youtube.com/watch?v=MuNag5fH_EI

[NewSciolyer]

Hey guys,

When I launched my glider (Guru 19, 28cm wingspan, 35cm fuselage) it launches up no problem, but on the descent, the right wing points to the ground the the glider sprials to the ground. I think it is because the wings were unbalanced, but when I added a bit of clay on one wing, it didn't really seem to help. This glider currently weights 4.2 grams and I am still looking for ways to reduce the weight. Thanks!

Many thanks,
NewSciolyer

[fifty_missions]

Can anyone reach out to me if they know any ideas on how to help gliders have a smooth transition? Currently, my glider just comes back down immediately without transitioning. Any other tips are welcome.

1) Easiest solution is to get the glider to stall and launch at a 45 degree angle with a bank to begin the process.

2) Observe results.

3) If glider transitions but stalls, two choices.... add some clay to the nose until the stall goes away OR bend some down elevator on the trailing edge of the stabilizer

4) Do adjustments in degrees or millimeters of change, nothing drastic.

5) Need more orbit? Bend the trailing edge of the fin like a boat rudder to increase or decrease orbit.

6) Once there is a transition, work higher with your launches. This may mean increasing the bank angle (Wing tip up or down using the fuselage as the axis).

Good Luck,
50 Missions

[Jdh3]

Hey guys,

When I launched my glider (Guru 19, 28cm wingspan, 35cm fuselage) it launches up no problem, but on the descent, the right wing points to the ground the the glider sprials to the ground. I think it is because the wings were unbalanced, but when I added a bit of clay on one wing, it didn't really seem to help. This glider currently weights 4.2 grams and I am still looking for ways to reduce the weight. Thanks!

Many thanks,
NewSciolyer

I’m sure you have already done this but:
1) does it hand glide ok? If not, it may have too much nose weight.
2) if you launch it with low power and level, does it climb slightly and then make a right turn before gliding? If not, what does it do?
3) have you rechecked the angle of the rear fin? If it is angled too much it will affect it significantly at high speed and the glider will not recover
4) is your right wing tip lower than the left but Not lower than the plane formed by the stabilizer?
5) have you changed your launch angles? What was the effect? Do you have any videos?

Thanks

[NewSciolyer]

Jdh3

1) Yes, it does hand glide okay with a little forearm flick, but any harder it will stall.
2) When you launch it horizontally with low power and no bank, it climbs linearly for 2 feet and then tries to transition right into a glider, but the right wing tips downwards, bringing the whole plane down.
3) I haven't tried reattaching the tail fin, and that might be the problem
4) The right wing is tilted closer to the stabilizer, but only a few degrees lower than the left, still above the stabilizer
5) I tried to launch it with no bank, and it doesn't work. I might have to try to bank it to the left to compensate, but I'm not sure if it would work. I don't have videos, sorry.

I think in the process for sanding the flap in the wings(flapper design) I think I sanded the left wing a bit more, thus creating unbalanced lift.

Thanks so much for replying!

NewSciolyer

[Maxout]

Jdh3


2) When you launch it horizontally with low power and no bank, it climbs linearly for 2 feet and then tries to transition right into a glider, but the right wing tips downwards, bringing the whole plane down.

This is a wing warp problem. Grab the right wing about 1" out from the fuselage and twist the part ahead of the flap so that the leading edge is raised relative to the trailing edge. Don't touch the flaps at all. If the wood cracks, that's fine, just harden it with ca glue. This should fix the problem, although you may find a need for more right rudder trim.

[Jdh3]

Jdh3


2) When you launch it horizontally with low power and no bank, it climbs linearly for 2 feet and then tries to transition right into a glider, but the right wing tips downwards, bringing the whole plane down.

This is a wing warp problem. Grab the right wing about 1" out from the fuselage and twist the part ahead of the flap so that the leading edge is raised relative to the trailing edge. Don't touch the flaps at all. If the wood cracks, that's fine, just harden it with ca glue. This should fix the problem, although you may find a need for more right rudder trim.

I agree.
You can often see the problem when you look at wings from the front. The problem wing (right in this case) will not be catching as much air and therefore not getting enough lift. The opposite wing will continue to get lift until it rolls over the airplane into the ground.

[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)

[fifty_missions]

I'm thinking there may be a mass issue. If your glider weighs over 4 grams, it is consuming too much energy to fly. A good analogy is take a 5 mile hike with loose change and a bottle of water. Take the same hike a week later... loose change, a bottle of water and a 100 pound knapsack. Which of the two hikes did consume more energy to get the job done? Heavy aircraft struggle to fly when overloaded. The cannot maneuver for the same reason. Transitioning is directly related to the wing loading. Small wing area and heavy construction and you just built an arrow. What you want is a design that can maneuver from the vertical to horizontal. That ability will be correspondent to the weight and wing area.

1) Josh is correct, the one wing that drops needs to have its leading edge up even higher. Cracking the leading edge and setting with CA is a very common fix. 30% of my own gliders (30+) have had this fix.

2) Same fix may help the transition to happen higher near the ceiling.

3) It is a bit sketchy when you say a launch at 20'-25'? Is that VERTICAL (90 degrees), 45 degrees, or almost horizontal?

4) Did you try to either reduce the nose mass or bend the trailing edge of the stabilizer up? Either would help bring the nose up to transition as the glider slows down at the apex of the launch trajectory.

5) If the glider has a severe roll to the right on launch, bank with the left wing tip lower than the right on the launch (banked left).

6) As I tell my students, build at least 5 gliders and one might be a winner. You may need to go back a build another. Get symmetric and use less glue.

One of these days we need to publish common terms with images for describing flight patterns. I believe many descriptions are being garbled by semantics.

Report back,
50 Missions

[AirplaneMan]

My glider was originally 3.7 grams, but after the repairs I made throughout the testing process, the glider probably weighs around 4.0 grams now.

1) Ok I'll try that but how do I crack the wing? I'm using a flapper FF design so there's carbon fiber on the wing. Cracking the leading edge won't also break the carbon fiber, will it?

3) That's a launch to about 20-25 feet vertically (20-25 feet straight above the floor)

Also, does rudder deflection have an impact on the transition? And if it does, what is the effect of increased/decreased rudder deflection? I'm wondering because I have a very wide turn circle right now, and when I slightly bend the rudder to get a smaller circle, the plane seems to become less stable in the flight.