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Trim Authority

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wingnut

Joined: 11 Jan 2006
Posts: 356

Posted: Mon Sep 17, 2007 7:44 pm Post subject: Trim Authority

I have electric trim on my model 4. It works great except for one thing; When landing with flaps, it doesn't have enough authority to trim hands off at 55 mph. I still need a fair amount of back pressure to keep the speed down. I'm still not comfortable landing at my 1200ft farm field with trees on both ends and being able to trim out all the back pressure would really help. Any ideas?

_________________
Luis Rodriguez
Model IV 1200
Rotax 912UL
Flying Weekly
Laurens, SC (34A)

kerrimikehickman(at)aol.c
Guest

Posted: Mon Sep 17, 2007 8:17 pm Post subject: Trim Authority

Hi, 

 

 I have a model 6, same initial problem, John McBean on his website I believe sells a tension spring (trim assist) which pre-loads the control stick and really does cure this ill...no more running out of trim w/the electric system, and hands-off to stall works great.  Give him a call.  Cheers.  Mike H.

 

 

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wingnut

Joined: 11 Jan 2006
Posts: 356

Posted: Mon Sep 17, 2007 8:40 pm Post subject: Re: Trim Authority

Does the spring system work in conjunction with the existing electric trim? How is it adjusted? Would I then have two separate trim systems to adjust?



 	  Quote: 	
		   have a model 6, same initial problem, John McBean on his website I believe sells a tension spring (trim assist) which pre-loads the control stick and really does cure this ill...no more running out of trim w/the electric system, and hands-off to stall works great. Give him a call. Cheers. Mike H.

_________________
Luis Rodriguez
Model IV 1200
Rotax 912UL
Flying Weekly
Laurens, SC (34A)

crazyivan

Joined: 25 Aug 2006
Posts: 62
Location: Pensacola

Posted: Mon Sep 17, 2007 11:07 pm Post subject: Re: Trim Authority

Here's a theory that might help...get the vortex generators from www.landshorter.com and install them on the bottom of your horizontal stab.  This should give your elevator more authority at lower speeds.  



I have the same characteristics on my Model IV Speedster but probably not quite as bad due to my shorter wing.  I actually prefer to run out of trim on final because I can better feel what the airplane is doing.  It also forces me to fly with the gentle touch and not be ham-handed.

_________________
Dave
Piper PA-22/20

dave

Joined: 22 Sep 2006
Posts: 1382

Posted: Tue Sep 18, 2007 1:57 am Post subject: Re: Trim Authority

Luis, 

1200 feet runway plus trees at both end ?   Well should be no problem fora Kitfox Long wing. Biggest thing is to learn the skills and practice them to make this easy for you. I would suggest practicing alot of slow flight at or a few mph over stall speed until more comfortable plus with up to 20 degrees flaps.  Then Side slipping with and without flaps. 



Find a grass strip about 2000 feet long with trees near you and try it in there then go to a 1500 foot one.  Then a 1200 foot one.  You should be able to get in and out of a 1200 foot strip pretty with no concerns after a while . Key is slow approach in control. What speed indicated does your plane stall at ? 



On mine I can approach at 45 to 50 mph and then sideslip down right to the ground, then kick it straight.  If you kick it too early on a long wing you will get more float.



As far as trim, I have none.  The Kitfox controls are so light It not a concern for me. 

this forum has some talk on VG testing that I have  done over the last few weeks http://forums.matronics.com/viewtopic.php?t=31939

 plus more here http://www.cfisher.com/vg.html

_________________
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Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Tue Sep 18, 2007 7:06 am Post subject: Trim Authority

To be honest I was wondering what all the talk  about the elevator trim was about.  My model III-A seems to trim out pretty  well (not quite hands off but close) without any other springs, tabs, or bungee  cords.  I have lots of elevator control while landing on floats.   Generally I touch down just before the wing stops flying and the stick is almost  all the way back.  In next to calm conditions I expect the plane to be idle  taxiing with in three hundred feet... It takes more space than that to get off  at gross.



I have a tab installed on my rudder to take the work out of  keeping straight at cruise.  It works like a charm.  The only thing is  as you take off or land you have to be on the rudder every second.  I think  a larger rudder would be the only change I would make.  I too like to use  slips and that little rudder just doesn't give me enough authority to pull a  good slip with the pendulum effect of the floats.



[quote]  --

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

wingnut

Joined: 11 Jan 2006
Posts: 356

Posted: Tue Sep 18, 2007 7:56 am Post subject: Re: Trim Authority

Thanks for the tips guys. My Kitfox came with a VG kit that the previous owner never got around to installing. I will try that first since it's something I already have. If that doesn't work, I'll look at that spring assist. 



No doubt that landing at my place will get easier with practice but while I'm learning, I expect that it will help to be able to trim for hands off during final.

_________________
Luis Rodriguez
Model IV 1200
Rotax 912UL
Flying Weekly
Laurens, SC (34A)

dave

Joined: 22 Sep 2006
Posts: 1382

Posted: Tue Sep 18, 2007 8:21 am Post subject: Re: Trim Authority

Luis, I don;t think you will find the VGs will be a better solution than perfecting your short field skills .   Take a few days when calm in the AM or before dark and do at least 10 circuits each time to try to hone your skills. 



I have a you tube video here  http://www.cfisher.com/vg.html    that at the end shows side slipping down to the ground over 80 foot trees . to land short over obstacles you will need to excel at side slipping and slow flight.

wingnut

Joined: 11 Jan 2006
Posts: 356

Posted: Tue Sep 18, 2007 8:38 am Post subject: Re: Trim Authority

I agree. No substitute for practice. I do it every chance I get. On the other hand, if there's some gizmo out there that makes the airplane a little easier to handle in certain situations, then that doesn't hurt either. Trimming the airplane for neutral stick pressure during final was part of my training and makes good sense to me. I don't see any advantage in having to hold back pressure during the approach.  



 	  Quote: 	
		  Luis, I don;t think you will find the VGs will be a better solution than perfecting your short field skills . Take a few days when calm in the AM or before dark and do at least 10 circuits each time to try to hone your skills.

_________________
Luis Rodriguez
Model IV 1200
Rotax 912UL
Flying Weekly
Laurens, SC (34A)

dave

Joined: 22 Sep 2006
Posts: 1382

Posted: Tue Sep 18, 2007 8:47 am Post subject: Re: Trim Authority

Luis,  Most of my flying is 500 agl or so and away from airports.  Alot of base legs might be only at 100 agl  or so so my  trim is not needed as much when at  1000  agl  airport circuits. 



But for sure practice it all.......... and especially  forced approaches as one never knows when you might have to find a spot to land with little notice.

MichaelGibbs(at)cox.net
Guest

Posted: Tue Sep 18, 2007 11:39 pm Post subject: Trim Authority

Luis sez:



 	  Quote: 	
		  Trimming the airplane for neutral stick pressure during final was 

part of my training and makes good sense to me.


	


It's an FAA requirement that certified airplanes be capable of being 

trimmed for their approach speed.  That doesn't apply to 

experimentals, of course, but I like it.



Mike G.

N728KF

Phoenix, AZ

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