My X8 launcher

[Coyote]

Well I wish it went a easily as the tests went .................... If only :)

After about 5 failed attempts finally got it :)

http://youtu.be/n5mqrpKLp4Y

Only two factors changed

1) Control throws reduced
2) Parachute put back on

When looking back at the previous tests / video the control throws seemed fine. So that left the parachute. Once the parachute was back on, the next two launches were OK. I had much better results pre new motor , but it was windy so the results I had to be happy with.

* Best viewed in HD *

[bignose13]

Lovely Ian, lovely  :-*

[FPVSteve]

Lovely!

[skyscraper]

Glad it worked in the end!

Interesting about the chute though. You got any theories about whats going on without it?

regards
Andy

[g.collins]

great going Ian, I suppose the shoot slowed the bungee down to release the plane nicely.
:) G

[Coyote]

Glad it worked in the end!

Interesting about the chute though. You got any theories about whats going on without it?

regards
Andy

I`m really not sure Andy. The control throws were lowered also but on the previous video it was fine with those throws every time so to me it must have been the chute stabilizing it imo

[Coyote]

great going Ian, I suppose the shoot slowed the bungee down to release the plane nicely.
:) G

Yes I think so G, or gave it some downward pressure ( directly below the hook ) maybe ?

[Flyn]

Hi Ian, looking good there mate, glad it works for you!

Just a thought, have you tried moving the mounting hook forward a little, the spin without the chute could it be because the hook is too far back, allowing the nose to raise above & away from the direction of the bungee pull causing the spin out?

The chute could be effecting the high pressure side of the wing lowering it a little -providing slightly less lift under the centre section, just enough to slow it & keep it level?

[Coyote]

Hi Flyn, no I`ve not tried moving the hook, but I see your point, you could be onto something there. I could then move the hook, but I`ll just save the trial and error and just leave the chute on, if it aint broke n all that :)

[skyscraper]

Just a thought, have you tried moving the mounting hook forward a little, the spin without the chute could it be because the hook is too far back, allowing the nose to raise above & away from the direction of the bungee pull causing the spin out?

Thats my hunch too. Same thing happens to a kite if you put the ring on the bridle too far back.

regards
Andy

[Flyn]

Fair play mate - if you got it working...

crazy that the chute is the only thing stopping a failed launch, if for any reason the chute fails so will your launch, that's a lot of trust in a tiny parachute!

If it were me I'd move the hook so I wouldn't be relying on the chute to keep the plane on track, but hey your toys mate, you get to play with them how you like ;)

Here's a pic of the hook position on my zed, launches great every time straight & level. Note the two cg pen marks either side of the large black decal

[Coyote]

Ill have a look, but moving the hook might be a lot of work

[Flyn]

ah ok, fair point. Should be ok I'm sure. ;)

[Skipper Billy]

Coyote - two things I have found (and I think you are using the same bungee as me) are -

1. The outside temperature makes a big difference to the pull on the bungee - recently its been hovering about 3 - 4 degrees here and 30 paces of stretch = 9kgs pull  but a few weeks back when it was 10 - 12 degrees 32 paces gave 8kgs pull

2. This is probably the most relevant having seen your video - after 10 - 12 launches from new - the bungee needs more paces of stretch to deliver the same punch - its worth checking with your luggage scale that the expected pull is actually there. Now mine has been used maybe 25 times it needs an extra 10 paces of stretch to deliver the same pull. When measured relaxed the bungee is now 12m long not 10!! It is now run in now I think!!  From your video it looks like a simple stall to me - the sort of result you get from a half *rsed hand launch. More speed off the ramp should cure it - the parachute will only slow it down off the ramp. If you want it to release earlier just bend the hook down a little.  To make it climb faster move the hook backwards towards CofG to keep it level but faster move the hook forwards - away from the CofG.

[Coyote]

Hiya

1) I didn`t know that

2) I have so far used scales for each launch, 50 paces +/- a few but I will use them on every launch now just to make double sure. Looks like Ill have to bite the big one and open it all up again and move the hook forward then :( Oh joy lol