building a glider

[hello183]

I took the glider for another flight, but it had an encounter with a tree.

Luckily only a portion of the leading edge between the ribs broke and I haven't been having trouble fixing it. It looks a bit crooked in the picture, but it is just the camera.

When it gets warmer, probably next year, I will take it to a bigger area where it hopefully will be able to reach some thermals and get longer flights. If I could launch this into a thermal and get it high up, it glides well enough that I could definitely lose it. I measured one of the flights and I think it got a glide ratio of between 16:1 to 20:1. It might be able to fly better if i change the wing incidence.

 

[danskis]

Nothing like flying something you made. Congrats.

 

[Tench745]

Sounds like a successful mission!

 

[hello183]

could I add spoilers to the wings and use those as a mechanism for the dethermalizer?

 

[danskis]

Watch this

 

[Piotrsko]

A dethermalizer needs to be very agressive, almost to the point of crashing to overpower the lift gained in a thermal. Typically, people try to cause a stalled spin which is gentle enough to not break things. Spoilers of at least 10% wing area might be enough, but I have seen thermals strong enough to carry porta potties away. Loosing your plane in a monster thermal is a rite of passage

 

[hello183]

It would be hard to cut off the control surfaces or the wing dowels, which are things I'd need to do to add a dethermalizer system like the ones in the video. But I heard of a pop up fuselage dethermalizer. What do you think about a system that disconnects the nose cone for the dethermalizer?

 

[danskis]

I'm unclear what disconnecting the nose would do. How about a parachute?

 

[hello183]

I was thinking that if I disconnected the nose somehow, the center of gravity would change and it would come down. But to not lose the nose I'd have to attach it with a string or something. Is there a way I could add a parachute while keeping the weight down?

 

[danskis]

Well the parachute was a dumb idea. In a large thermal it would probably make the plane go UP. Your idea is better

 

[hello183]

I was thinking of designing a bigger glider with radio control. I won't do that now, because I want to learn how to fly first. What carbon fiber tail boom would you use for a glider that is big, but meant to go quite slow? The wingspan right now is a bit more than 2 meters, and the fuselage is about 1.4 meters. I was thinking about one with a 10 mm diameter. I couldn't find any tube long enough online. Where would you look for it?

 

[danskis]

10mm sounds perfect. How are you going to get it in the air? Hi sart, motor, or throw it. A 2 meter glider is perfect for learning how to fly RC.

 

[danskis]

You have options with the boom. You can make a nose that goes from the back of the wing forward basically a box out of foam board or balsa or a combination of both. and use the CF boom for the back. Or you can buy two shorted booms and splice them together.

 

[hello183]

I was thinking about using a motor, but I may just use a towhook. I was going to build a balsa pod in the front, but even with that, the boom would need to be 95 cm. I could only find 50 cm booms online. How could I splice booms together?

Also, should I put this discussion in a different thread?

 

[danskis]

Try this link for a boom. There are other sources out there. I've got 3 world class 2 meter gliders at home and they all have roughly the same fuselage dimensions. I'll be home in a week and let you know what they are. If you use a motor a folding prop will double your glide performance.

https://alofthobbies.com/collections/carbon-fiber/products/mandrel-wound-carbon-fiber-tubes

 

[danskis]

https://jonesairfoils.com/collections/airframes/products/exel-carbon-tubes

 

[Piotrsko]

There's also fishing rods and arrow shafts. The arrow shafts have a common diameter that uses a readily available carbon shaft as a splice, Saw a 9 ft fly rod at the local Goodwill for $5 that needed the ferrules taken off the lower half

 

[danskis]

More tail booms-what piotrsko said

https://www.rcgroups.com/forums/showthread.php?2074251-Tapered-tail-booms-(fishing-pole-blanks)

 

[quorneng]

I use tapered glass fibre fishing rods as tail booms.

ct that there are tapered actually, The fact in part, matches the bending forces so reduces the deflection for a given weight. With a "V" tail the micro servos are mounted in each tail plane and the wires run up inside the boom.