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Skwalker X8 catapult

Posted by brett binnekade on February 1, 2013 at 5:00am

With the amount of equipment in my X8 is on the increase, so is the weight. Its becoming very difficult and somewhat dangerous to hand launch. 

Iv decided to build a catapult. I dont like the idea of a bungee launcher because of the amount of flat space required. some places I fly dont have this.(eg: off a cliff =) ) I really wanted something self-contained and foldable.

 

The APM flies the X8 really well BTW =)

 

If anyone wants to build one I have posted all the info and pics here

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Comments

  • Moderator
    Nathaniel Caner March 11, 2013 at 4:13pm

    What keeps it in the cradle when you power up? Just friction? I like the design overall and would like to make a modified version for my 6lb Super Sky Surfer!

    Regards,

    Nathaniel ~KD2DEY

  • Richard March 11, 2013 at 3:33pm

    Hi Bret, I'm having a bit of difficulty with the build, and was wondering if you could answer a couple of questions,

    How did you make the joiner so that it doesn't bow in the middle, the middle of the rail is bowing down a bit causing it to bump in the middle. I've removed the clips and put a 1 meter piece of wooden block inside it for now.

    Secondly, how much tension did you put on the bungee chords? The Latex stuff is absolute rubbish, so i'm using traditional bungee, but the plane is just falling off the end of the catapult, seems like i need a tonne of pull, more than I would expect, the plane is only 2kg.

    Lastly, the carriage is coming off the rails at the end, it seems the bearings on the bottom ride out causing the rear two axles to come off the rail completely. I'm wondering if the 8mm bolts are too thin, what diameter bolts did you use?

    Can't wait until the first launch!!!

    Cheers

    Rich

  • Richard March 9, 2013 at 6:32pm

    Hi Bret, The Catapult is complete (almost). Just need to work out the correct bungee tension, though i's start with long bungees and cut them down to get more tension. I'm using 8mm latex bungee chord which stretches 6 times it's length. I also have some traditional bungee chord to use if i need more tension.... 

  • Richard March 8, 2013 at 5:22am
    Hi Brett, first off I will be launching some 60inch wings loaded with cameras. I've used my homebuilt wings to test apm, inkitially I had a skywalker but apm/my config wasn't good enough and crashed it. So wanted to use a cheap 'unbreakable' airframe until my faith is restored!

    I do have an unbuilt x8 waiting for a suitable motor
    To be installed. But I'll make sure I post the first launch, regardless of the outcome!!
  • brett binnekade March 8, 2013 at 5:09am

    That looks awesome Richard! thanks for sharing your build. Will you be lauching an X8 too? very keen to see it launch!

  • Richard March 8, 2013 at 3:32am

    Cheers for posting such detailed information on RCG, I've almost finished mine, It has some minor changes but largely the same. 

    I am planning on using Auto take off for the first time with my wing on this catapult. Total cost for parts was less than £100. the tricky bit was drilling the holes for the 4 bearing bolt axles, make you measure this a few times!

    some close-ups, i'll post a video of the first flight!

    3692645266?profile=original

  • Matt February 24, 2013 at 4:52pm

    Have you tried to launch this in Auto or Stabilize mode? Is the APM able to deal with the large acceleration numbers?

  • brett binnekade February 17, 2013 at 4:07am

    Chad, there is a link on the blog post to my build thread.

  • Chad Frazer February 16, 2013 at 11:27pm

    Please add a bill of materials and some drawings!!!

  • Jay Bryon February 12, 2013 at 4:57pm

    Nicely done indeed!  Thanks for posting your data!

This reply was deleted.