Graupner Mini Discus 2C

I found this cute little free flight glider when I was visiting a local RC event and I just had to have it. The plan is to convert it into a RC glider using nothing more than two servos, a battery and a receiver.

Specs stock:
Wingspan: 650 mm
Length: 450 mm
Wing area: 5.4 dm2
All-up weight: 85 g

Electronics I planned on using:
Battery: 1s 350mAh 20C LiPo
Servos: 2 x Turnigy 1440A
Receiver: 4 channel Assan X8R4H

I was very pleasantly surprised when I took of the canopy. A huge 24 gram hex screw was placed inside of the canopy to get the CG right. Perfect. This means that I can use all the electronics up front.

I cut of a piece of the vertical stab and replaced it with a bigger piece of depron to make a rudder.

I cut the horizontal stab and beveled it on the underside to make the elevator.

Time for a cutting edge procedure.

I used 0.4mm piano wire as push rods.

Elevator linkage

Rudder linkage

I used a loop of “hot wire” that gets hot when you run current through it, to make trenches for the push rods.

Simple and fast.

I used a scalpel to make the cut outs for the servos and make a battery/receiver well.

Done! I glued the two sides together, connected the push rods, dropped in the receiver and battery and added some esthetics.

The underside.

Under the hood.

After the first flight I added some 1.5mm plywood to reenforce the nose.

Pushrods again.

All up weight: 97 grams. Time to fly.

It flies great! Not much wind is needed to keep it in the air. It’s so much fun trying to find lift over bushes, mounds and other stuff in the vicinity. I like it a lot! I have yet to try it out on a “real” slope but I’m sure it will perform great there as well, as long as the wind isn’t to strong.

4 thoughts on “Graupner Mini Discus 2C

  1. Very nice and simple!! I’ve seen a lot of videos of people turning the Multiplex Fox into a hotliner wingeron but I think it just takes the fun out of gliding. This on the other hand is a great blast from the past for putting 2 traditional RC channels into a tiny, almost pocket-sized glider… LOVE IT!!

  2. That’s a real aswome job David! I’ve got this dromida Twin explorer that sucks and didn’t work and I want to to a mod similar to this. Your boild log inspired me so thanks! 😀

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