collective/fixed pitch
 

Another newby question.......As I understand it with fixed pitch, up and down flight is controlled by throttle speed. Here is where I get confused, with collective pitch is it controlled with the throttle or pitch of the blades or both? Sorry for my ignorance, I am still new!

RE: collective/fixed pitch
 

No problem, if you have a question just ask.

The pitch of the main blades is changed collectively (hence the name :)) by the throttle stick, which is also slaved to the throttle channel.

As you increase the blade pitch you increase the lift but you also increase the drag so you need more power so you add throttle at the same time you add pitch. The effect is that the blades always spin at the same RPM no matter if they are producing full power lift, or 0 pitch just sitting there.

One of the problems with fixed pitch is that descending requires lowering the head speed, so if you want to power back up or you get into trouble you have to wait for the RPM to pick back up before the head produces lift. With a CP machine the RPM is the same so you can recover very quickly.

RE: collective/fixed pitch
 

NVM, the post above makes more sense than what I was saying:)

RE: collective/fixed pitch
 

Ok, that makes sense to me. Iwashopingyou wouldn't have to run the throttle and blade pitch seperately, I know i don't have that much coordination! Thanks for the info, i appreciate it !

RE: collective/fixed pitch
 

the throttle and collective are run together. when you increase throttle you increase pitch too. provided the pitch curves are set up right. they should be 0 pitch at idol, 5 degrees at mid stick [hover position] and 9- 10 degrees at the top. if it's a five pitch curve radio then split it up. same with the throttle and ajust from there. while you are test flying the heli. always land first, then make ajustments. even on your blade tracking.....good luck.........geeter.

RE: collective/fixed pitch
 

I don't think many people on the planet would have that much coordination.. http://www.rcuniverse.com/forum/js/f...wink_smile.gif

Collective Pitch Heli setupseems daunting at first but it all makes sense once you see it in action...

This video explains things pretty well..

[youtube]http://www.youtube.com/watch?v=cf5iG299hzk[/youtube]

RE: collective/fixed pitch
 

You'd be surprised what we put up with in the old days! The Bell 47 full scale the throttle was on the collective, you had to twist the throttle as you added collective which would cause the nose to turn so you had to be on the pedals at the same time :)

RE: collective/fixed pitch
 

Oh yes, I understand.. when I did my heli conversion (full size) in an R22 we had to demonstrate 3 circuits with no governor.. IE manual throttle control...

It was certainlymore difficult.

Actually if you had a seperate slider on an RC TX for setting the throttle it would be just like using a flat throttle curve stunt mode, and probably not too difficult at all..

egjust set 90% throttle and fly on pitch alone (which is what a flat throttle curve does anyway)

(didn't think about that before my last post..)