Hi Guys
A few weeks ago Brett Binnekade put a catapult launch system http://diydrones.com/profiles/blogs/skwalker-x8-catapult on here for his X8 that worked pretty well. I value my fingers and arms and decided to make something along the same lines. I give full credit to the orginal design.to Brett.
I used the same general layout and tried several times to get a joint to work reliably to enable the ramp to brake down into 2 sections so it will fit in a normal car. The method I use now works very well.
The other problem was the stiffness of the trolley, the design I now use is much stiffer and reliable.
I used more elastic which is now over pulleys to get a longer pull and a stopping system for the trolley to avoid smashing the trolley into the end stops at the top of the ramp.
The final result can be seen in operation at http://youtu.be/Eobl_iSa_cs The ramp has operated more than 100 times with no failures and the launches are very repeatable and positive..The catapult and cradle can be modified for most aircraft up to 6-7kg.
Replies
how much and how much without the 2x2 32570 thanks
Hi Arnaud and Kevin
The Catapult has progressed over the last few months and is now available in 2 forms.
The original that we designed is available and works very well but we decided to restrict it to UAV's below 2.5Kg (like X5 etc. )
The 2nd version we now make is for the larger UAV's such as the X8, it is a heavier duty unit and has interchangable cradles for different aircraft including some tractor aircraft with nose mounted motors.
They are available on www.air-vision-air.com or sales@air-vision-air will bring you more information.
The website is being updated later this week.
Hi Martin
The main improvements were to the trolley which now uses a thin centre plate and box sections to support the pins for the bearings. This prevents the frame flexing and the bearings moving away from each other due to the launch stresses.
The bungee also goes over pulleys down to the bottom of the ramp . this gives a steady pull along the total ramp.
you can also see the attach points for the restraining cords used as a brake, This is stretchy polyester cord. with a spring at the bottom.
This other picture shows the attachpoints at the bottom of the ramp with the shock springs.
When the launch is set up the 2 springs hang down vertically with the cords loose on the ground, As the trolley gets near the top the cords tighten and lift the springs horozontal, this starts the plane to slide off the trolley a moment before the trolley stops as the springs stretch.
The Catapult produces approx a 3-4 G acceleration and the plane leaves at about 25mph in a good flying attitute , then I start the motor and climb out.
It Works.
Main benefit. I can still count to 10 at the end of a flying day, I dont strain my shoulders trying to throw this plane and the model does not get damaged by a crappy launch, everything is MUCH more predictable and safer,
The Catapult will fold up and go in the back of a small car (ford Focus) very easily and takes about 5 minutes to set up.
That works really well, what a nice smooth action, especially the stopping system.
Any chance that you could post up some shots of the improved component parts for us please.
Thanks
Martin