Airskipper (JR head) and FAI setup issues.

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RunRyder	RunRyder

Home › 🏆Contest › ✈️Aircraft › 🚁Helicopter › 🏆Aerobatic FAI F3C F3N Contest › Airskipper (JR head) and FAI setup issues.

05-21-2007 09:16 AM 13 years ago

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John M

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Next door to the Wombles UK

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Airskipper (JR head) and FAI setup issues.

Hi guys based on another post, Please see "Vibe and FAI".

I have some setup issues on my B machine and decided to post them here hoping that someone has had the same issue before.

Please note. Issues are noticed on my B machine only and I have not had an issue on my A machine until it recently met terra firma.
New servos (A has Futaba and B has JR)

The problem is airos and the "erraticness " of them. Previous helis you put them vertical in stall turn and you can make yourself a cup of tea. This heli I have always had to fight the machine in every axis when applying collective.

E.g. Loops, as I go over the top end of a loop and come off the (1 O’clock) power gently the heli skews (tail) and I am fighting cyclic continuously to try keep the ship strait. If I just use back elevator (as a test) it would exit nose pointing directly to me or out depending on direction.

Stall turns... as you collective power up into them I am always fighting cyclic (right/left). if I just used elevator the heli would proceed right so I am almost looking at the heli sideways.

Rolls are perfect!
Straight flight is perfect.

I think I may have found the underlying problem but not sure of the solution.
After trying the lighter FAI flybar setup I had to readjust the tracking (as you would expect) pulling left down the field so add three click and sorted, dead straight and no pitchiness whatsoever. But when I got to the end of the field and I add collective and power (Full stick) I noticed the heli wanted to roll to the right and tuck forward. (Only a the top of the collective.)

By eye (not levels or lasers) we looked at the swash on a bench and could not see any unevenness throughout the collective travel.
It did dance slightly as a I passed through 50% to 70% but at full collective it was still level.
Blades track level in hover and idle UP.

Any areas I could look or if someone could recommend a basic test.?

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05-21-2007 10:10 AM 13 years ago

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John M

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After doing some investigation it looks like I cant just rely on level swash and need to do some climbouts to test if CCPM is pulling left or right.

I will keep you all posted.

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05-22-2007 03:49 PM 13 years ago

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Spacey

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Pretoria, South Africa

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In my humble opinion a decent swash leveling tool is a must for every F3C pilot. It is just my opinion though and not law, I would be lost without mine though.

Your problem though has me thinking you might have a cyclic servo having trouble with holding torque, like it's sort of not able to handle the loads in the scenario you descibed and then you get a wonky output to the head. Maybe try putting some load on the servos on the bench (Carefull here! Don't burn them out) and try to see if one is maybe suspect. My first thoughts were washout but you say it rolls perfectly so ya that's ruled out.

Without a decent swash level though you wouldn't pick up if you have a servo horn somewhere that's a degree or what out and this will definitely transfer to the swash in terms of it staying level throughout the pitch range.

If you don't get a swash level you could always try increasing the servo travel limit on the servo that is lacking so it moves further than the others in the scenario described. But yes I would rather get a swash level and confirm that this is indeed the problem.

There is a few other things which could cause your problem as well but lets rather rule out these first.

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05-22-2007 03:53 PM 13 years ago

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simon109

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Hampshire UK

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I use this one http://www.miniatureaircraftusa.com...l.asp?prod=0513 excellent tool

Simon.

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05-22-2007 04:33 PM 13 years ago

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ErichF (RIP)

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Sutton, NH

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Spacey,

So what you're saying is, get a swash leveller? I think you mentioned something about them

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05-22-2007 06:15 PM 13 years ago

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Spacey

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Pretoria, South Africa

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I was trying to keep it subliminal? LOL

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05-24-2007 01:27 AM 13 years ago

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mdu6

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Montreal

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Washout stopper and phasing ?? (I know the rolls are OK ...)

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05-30-2007 02:28 PM 13 years ago

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John M

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Next door to the Wombles UK

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Thanks for the replies

Quick update
The swash looked relatively straight until I used a small level.
I noticed a problem on the "pitch" servo. It was extending about 5% extra travel throughout the collective range.(bottom and top) This was not immediate noticeable as all servos where smooth and reaching their stops perfectly at the same time.

As I had 0 subtrim and 100 travel decided to swap the servos for three (other) new ones. Immediately things sorted themselves out. used the level again and there was minimal swash deflection throughout travel (The bubble only moved between the spirit level lines) with 0 subtrim 100 servo travel and full collective travel. I only noticed swash deflection when moving collective very very quickly.

I am 99% the initial issue was an out of sync servo!

I decided to take this one step further and try the new CSM cyclock. (just as a bench test) I am so impressed with this little device. Swachplate moves up an down like mccpm swash with absolutely no visual interaction by default (spirit level) . even reseated the small level on the swash as the bubble was not moving.

Proof will be in the flying so hoping to test everything this weekend.
Will keep everyone posted.

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06-11-2007 08:39 AM 13 years ago

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John M

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All sorted!

Was one out of sync servo as mentioned before.

CSM Cyclock works a treat!

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06-11-2007 11:47 PM 13 years ago

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nicco

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Sweden

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IS it allowed to use a Cyclock on an F3C heli?

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06-12-2007 12:22 AM 13 years ago

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ErichF (RIP)

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Sutton, NH

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You can use a Cycloc, but you can't use the gyros that allow it to stabilize a flybarless head. All you can use it for, to my knowledge, is as a CCPM mixer.

Erich

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RunRyder	RunRyder

Home › 🏆Contest › ✈️Aircraft › 🚁Helicopter › 🏆Aerobatic FAI F3C F3N Contest › Airskipper (JR head) and FAI setup issues.

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