Thread Tools
This thread is privately moderated by Shikra, who may elect to delete unwanted replies.
Mar 26, 2010, 03:02 PM
SILURIA / UK
Shikra's Avatar
Thread OP
Discussion

FPC Catapult Bungee Launcher Mk2


OK I built this to try to simulate a hand launch, but hopefully better due to consistency.
10m length 5mm Bungee.
Cariage total length = 2m. Approx 1.5m used for launch
Trigger operate via TX controlling a rx on the launcher
- I have it on ch3 so whan throttle reaches 60% it releases
First test run with full tension of 10lbs. At release this drops to 7lbs.
Tension will go considerably higher. Next Launch might try 15lbs
Safety pin to prevent accidental launch!

The plane holder is removable for different types of planes. Build to the best attach point. For the funjet I used a pusher style - check out the pictures.

Funjet best launch angle is 60 degrees for me.


Making your own? Best tips...
Keep the carriage as light as possible
Build to launch with power on at lower tension

First RC test video:


First FPV launch:
Last edited by Shikra; Apr 21, 2010 at 03:46 AM.
Sign up now
to remove ads between posts
Sep 14, 2010, 10:12 PM
That's falling with style!
RowdyRod's Avatar

Catapult Bungee Launcher


Hi Shikra,

You have done a beautiful job on your catapult launcher. I have used a bungee hi-start type launcher a few times but I’m planning on building something similar to yours as I don’t need the height and I want something that is safer and self contained.

What method have you used to slide the carriage or dolly over the rail? Is it using wheels or is the wood simply sliding over the aluminium box section?

Any additional photos, design sketches or videos you have would be most welcome

Cheers,
Rod.
Sep 15, 2010, 03:46 AM
SILURIA / UK
Shikra's Avatar
Thread OP
I don't have any more pics, but do hope to do a vid one day. Close up so people can have a look. I never completed the bit that holds the plane - it's still a prototype and looks a bit rough so really wanted to build a new one before shooting some vid.

For the carriage it is like this:-

Centre tube is aluminium box.
The upper and lower outer parts are 3mm aluminium plate
The outer side pieces are wood
The wood and aluminium plate I lines with some 2mm plastic sheet

I spray a little bit of polish on the carriage and it is very smooth - very little friction.

The real trick is to make the carriage / plane mounting assembly as light as possible - but it needs to be strong enough to survive hitting the end stop.

For the end stop I ended up modifying the aluminium bump stop you can see and instead adding 60mm of pipe insulation foam around the centre tube - wrapped multiple times with electricians tape to make stronger. It works well.

The overall length is 2m. I think for light plane this could be reduced by possibly 50%

I have had maybe 50 launches now, but since solving a problem with my funjet I have not used it recently. I think when the weather gets cold I will fly from inside my car and use it to launch remotely from inside. (I fly FPV)


Quick Reply
Message:
Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Air catapult or bungee launcher for EasyStar or other FPV plane? UFO_MAN FPV Aircraft 32 Apr 16, 2013 05:18 AM
Question Is 3/16 Bungee cord OK for catapult launcher? Windbird Electric Plane Talk 12 Aug 25, 2009 07:50 PM
Discussion Large Scale Bungee/Catapult Launcher? scdwyer Flight Accessories 3 Aug 06, 2009 03:42 PM
Found Catapult or bungee launcher for EDF druegeme Aircraft - General - Miscellaneous (FS/W) 3 Jan 04, 2008 08:43 PM
Catapult or Bungee launcher? Doc Dyer Electric Ducted Fan Jet Talk 3 Mar 21, 2002 04:25 PM