Today I christened my new plane launcher with success. I have built this as I have found the properties where I want to fly from have little or no adequate takeoff areas since the fields are full of waist high grass or lots of rough ground. Landing is OK by slowing down and dropping into the long grass but takeoff has been hazardous, to say the least.

The launcher is using an 900mm air ram to drive a 6:1 ratio pulley system that accelerates the launch trolley up the ramp. The ramp is made from 2 x 50mm x 25mm C sections welded together and bolted together in 2 x 3m sections that can be broken down for transport. 

The trolley has a front wheel hold down that is released at the end of the ramp and hopefully this coincides with flying speed.

The speed is adjusted by altering the air pressure from the compressor. So far it is launching at approx 100 psi without ripping any wings off. As the compressor is rated to 150 psi it has some spare capacity for larger or heavy flying weights.

So far it costs about $300, the ram was an ebay special for $50. I sourced the pulleys from ebay by buying someone's unused gym weight machine, which has 125mm glass fibre pulleys complete with bearings (which to buy separately would have been $15-20 each.) I was also able to use some of the gym machine's steel for legs and some of the frame.

 

richie 

Views: 2454

Comment by Rob_Lefebvre on June 16, 2012 at 5:47am
That's awesome!!!
Comment by Michal on June 16, 2012 at 6:07am

This is great! What is you trainer weight? Only a lil bit messy at the end of launch ;). I am looking forward to see the construction details :)

Comment by Richard Unwin on June 16, 2012 at 6:25am
The boomerang 60 weighs 3.3kg plus motor 200grams, batts 900g ( 7000mah x 6 cell), apm1,servos another 200 grams or so, total about 5kg and i could probably carry a fair bit more as its pretty docile and the wing is huge.

Richie
Comment by Nick Arsov on June 16, 2012 at 10:00am

Hi Richard,

Can this be redesigned for planes such as CloudsFly, EagleWing, etc. planes without landing gear?

Best regards

Nick

Comment by Richard Unwin on June 16, 2012 at 1:15pm
Nick, yes, the trolley design is a simple sliding frame and would just need an adjustment to your planes dimensions and adding some hard points to the plane, i left the gear on the boomerang as i wanted to be able to power the engine as it slides up the ramp on the rams power so that it is going by the time it hits the end of the ramp and the is little or no sink at the end, it would propably work with say a flat wing style plane with engine off until past the end of the ramp, or build a high leg frame to allow prop clearance.

Richie
Comment by Rigel on June 17, 2012 at 12:56am

Very nice!  Any chance you could post some close up pictures?

Comment by Richard Unwin on June 17, 2012 at 3:29am

Carl La France, i not sure what your question means but the plane is a pretty docile one and would normally take off in about 20 - 30 meters on good grass, its too heavy to hand throw. 

Rigel, i have made another post with pictures, its just awaiting approval.

richie

Comment by Seppo on June 17, 2012 at 7:20am

It is impressive to see this launcher in action.  Launches the Boomerang with no issues at all.

Thinking about asking for a launch for some of our other random planes next time Richard has it setup ! :) :)

Meanwhile - thinking about a release mechanism for gear-less planes.

Comment by Richard Unwin on June 17, 2012 at 4:38pm

Seppo, we can just try the string around some random part of the plane and see what happens....

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