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Rick Rotorhead · 04-29-2007, 08:22 PM

Hi guys, this problem I got with the tail blowing out during pitch up. Well I notice there is a fair bit of slop in the plastic yoke where it fits around the spigots on the pitch slider. It allows several degrees of tail blade pitch change with no movement at the tail push rod! It was like this from new. Should there be any slop here - could that be losing me tail pitch and hence tail authority. I could maybe put some thin walled plastic tube over the spigots to help them have a tighter fit in the yoke - what do you think?

One other thing - I'm using a smaller distance from the servo centre screw to the ball, about 6mm, what would happen if I used a long servo arm (say 11mm) would it help at all?

jpolidore · 04-29-2007, 09:34 PM

Hey Rick,
I too thought I had a tail problem, until I really slowed down my movements to realize it was me adding rudder in hard collective moves. I would push up on the stick in flips or rolls etc. and I was adding rudder. Just a thought.

ukgroucho · 04-30-2007, 04:31 AM

You can rule out dumb thumbs by adding a little expo on rudder. Some folks use it all the time... I've tried and it does not suit me as I learned to fly without it but it does help prevent unwanted rudder input when you pop the throttle.

If the tail is kicking out then you need more gain. I assume that you went thru the set-up of the tail from scratch once you had re-positioned the position of the connector on the servo horn?

You absolutely do not need (or want) a longer servo arm... in fact with 11mm I suspect you'd struggle to get the Limit on the 401 low enough to prevent binding. Limit on the 401 wants to be in the 80 - 100 range - find (or drill) a hole in the servo horn that gives you that limit with absolutely complete throw on the tail slider.

If you have that set up then check for binding.
If you're using the pushrod guide (under the tail fin) then make sure it is LOOSE - they tend to be WAY too tight a fit, I don't use them.

Yes the plastic yokes have some slop... does not cause problems for most 'normal' flying.

04-29-2007, 08:22 PM	#1 (permalink)
Rick Rotorhead Join Date: May 2006	Tail Questions? Opinions please...... Hi guys, this problem I got with the tail blowing out during pitch up. Well I notice there is a fair bit of slop in the plastic yoke where it fits around the spigots on the pitch slider. It allows several degrees of tail blade pitch change with no movement at the tail push rod! It was like this from new. Should there be any slop here - could that be losing me tail pitch and hence tail authority. I could maybe put some thin walled plastic tube over the spigots to help them have a tighter fit in the yoke - what do you think? One other thing - I'm using a smaller distance from the servo centre screw to the ball, about 6mm, what would happen if I used a long servo arm (say 11mm) would it help at all?

04-29-2007, 09:34 PM	#2 (permalink)
jpolidore Registered Users My HF Map location Join Date: Aug 2006	Hey Rick, I too thought I had a tail problem, until I really slowed down my movements to realize it was me adding rudder in hard collective moves. I would push up on the stick in flips or rolls etc. and I was adding rudder. Just a thought. __________________ T-REX 500 ESP T-REX 600n Pro, O.S. 55, Outrage 56 AMA #900910

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04-30-2007, 04:31 AM	#3 (permalink)
ukgroucho Registered Users Join Date: Oct 2005	You can rule out dumb thumbs by adding a little expo on rudder. Some folks use it all the time... I've tried and it does not suit me as I learned to fly without it but it does help prevent unwanted rudder input when you pop the throttle. If the tail is kicking out then you need more gain. I assume that you went thru the set-up of the tail from scratch once you had re-positioned the position of the connector on the servo horn? You absolutely do not need (or want) a longer servo arm... in fact with 11mm I suspect you'd struggle to get the Limit on the 401 low enough to prevent binding. Limit on the 401 wants to be in the 80 - 100 range - find (or drill) a hole in the servo horn that gives you that limit with absolutely complete throw on the tail slider. If you have that set up then check for binding. If you're using the pushrod guide (under the tail fin) then make sure it is LOOSE - they tend to be WAY too tight a fit, I don't use them. Yes the plastic yokes have some slop... does not cause problems for most 'normal' flying.

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