Sunday, July 19, 2015

Making Model Gliders

KIT GLIDER

I have recently started making model gliders.  The first glider I built was a balsa wood kit bought from the local hobby shop.  The kit consists of 7 pieces.  2 wings, 1 tail plane, 1 vertical fin, and fuselage and 2 wing supports.  
Kit glider

Before assembling the kit, I had to use sandpaper to give the wings a shape like an aerofoil.  Next I used SuperGlue to attach the wing supports to the fuselage and the wings to the fuselage and wing supports.  Lastly, I attached the tail pieces.

Kit Glider wing supports

The most time consuming part was shaping the the wing profile, and the most difficult part was getting the angle of the wings the same on both side.
Kit Glider replacement fin
It flew quite well.  After a few hard landings, the tail fin broke off, and I replaced it with a plastic fin. The heavier fin meant I had to add some weight to the nose. It still flys quite well.


HOME MADE GLIDER MK1

My next model glider was a home made copy of the kit plane built from balsa wood.  I cut out all of the pieces using a craft knife.  I shaped the wings and assembled the plane as described for the kit.  This glider was a lot lighter than the kit, mainly due to the balsa fuselage.   I added sticky tape trim-tabs to the outer wings.  The glider flew really well, until it had one too many hard landings.


Mk 1 built from scratch using balsa wood

Home made Mk 1



The material I used for the fuselage a mistake, as after one or two hard landings, the fuselage broke just behind the wing.  I used a wooden kebab stick, which I split down the middle, to repair and reinforce the fuselage.  After another few hard landings, the balsa broke yet again, just behind the reinforcing.  I added another layer of reinforcing, combined with added weight on the nose.  This has resulted in a really fast glider that can handle high wind speeds.  The trim tabs help during slow flight, but are too floppy to make much difference when I throw the glider really hard.

Mk 1 Fuselage repairs

HOME MADE PIZZA TRAY GLIDER

After doing some research on the internet, I found a video by GrandDadIsAnOldMan on how to build a glider using a styrofoam plate.  The next time we had pizzas for supper I built my Mk 2 glider.  I cut the fuselage from some scrap ply wood and built the wings and tail plane from the styrofoam trays that came with the pizza bases. 


Mk 2 Plywood fuselage and polystyrene wings

Instead of using SuperGlue, this time I used a hot glue gun to assemble the model.  I got the centre of gravity wrong, so I had to add some weight to the nose.
Mk 2 nose weight.  Ply wood and hot glue


The glider was very light and after a few flights in a moderate wind, a wing broke off.  After repairingthe wing, I added a layer across the topof the wings for strength.

Mk 2 - Broken Fuselage
The next problem was the fuselage.  After a few more test flights, it broke in the same place as Mk 1, just behind the wing.  Obviously, the ply wood I had used was not very strong.  This time I used a split chopstick to reinforce the fuselage.  Then the tail fin broke off.


Mk 2 - Trim tabs

CONCLUSIONS

If you want to make a model glider, be sure to use strong wood for the fuselage, or reinforce the fuselage BEFORE it breaks.  Bamboo chopsticks work really well for reinforcing.

If you use styrofoam for the flying surfaces, you will need to reinforce that too.

Happy building!







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