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07-05-2012, 07:14 PM
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Join Date: May 2008
Location: Boulder, CO
Posts: 191
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Very squirrelly tail wheel controllability
Hello out there,
In the operation of my new -8 I recently purchased (I'm a former -4 owner),
It is noticeably "squirrly" on taxi out and especially on landing after the tail comes down (almost ground looped it the other day - thought my rocket steering link broke or went over center!!). I have checked my toe in and out and have determined its slightly toed in.
I am wondering if my steering link really did lock over center as I felt I had no control for a few seconds when it made a hard right !
Has anyone ever thought of using dual rocket steering links - one for each side?
I would think this might solve the erratic steering problem?
My rocket link rod ends are as far out as they could be to fit the steering arm on my new Aviation Products tailwheel.
Maybe I should go back to the chain set up !?
Thanks for your comments....
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07-05-2012, 07:28 PM
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Join Date: Dec 2010
Location: Hilton Head Island
Posts: 1,089
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Are you sure the tailwheel locking pin is engaged?
If not, remove it, clean it and relube it.
Good luck and congrats on the new 8!
__________________
John Mastro
RV-8
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07-05-2012, 08:12 PM
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Join Date: Jan 2005
Location: SC
Posts: 12,887
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Replace the link with springs until you get used to the -8 and/or figure out what is going on with your landing gear.
__________________
Bill R.
RV-9 (Yes, it's a dragon tail)
O-360 w/ dual P-mags
Build the plane you want, not the plane others want you to build!
SC86 - Easley, SC
www.repucci.com/bill/baf.html
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07-05-2012, 09:11 PM
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Join Date: Oct 2005
Location: Commerce Twp. Mich.
Posts: 41
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I know everybody has their opinion, but if you have any toe in it WILL be squirrly. I have experienced it on a cub and on snowmobiles. The cure is 0 toe or slight toe out. Speaking from experience.
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Mike T
Milford Mich.
RV 7a in progress.
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07-05-2012, 09:41 PM
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Join Date: Aug 2007
Location: Wichita Falls, TX
Posts: 2,182
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One rocket link is plenty enough as long as your toe-in/toe-out is correct and the rocket link is adjusted correctly. I had some issues with the tailwheel pin not locking on the RV-8 but it really wasn't that squirrely. Turned out I needed to carve the locking pin's slot in the control arm a bit deeper per Vince Frazier's instructions and that fixed the missed-locking issue.
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Neal Howard
Airplaneless once again...
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07-05-2012, 09:42 PM
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Join Date: Mar 2005
Location: Dallas area
Posts: 10,768
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Mike has it right. I discovered this while designing the landing gear for my Moni Motorglider.
Got most of my design information from Pazmany's book on landing gear design.
Think of it this way; if you have toe-in and you begin to swerve left, centrifugal force places more weight on the right wheel. If this wheel is toed-in, it will cause the aircraft to swerve MORE to the left. On the other hand if the wheel is toed-out slightly, it will cause the aircraft to be pulled straight.
I know there is a lot of controversy on this subject, but when I built my gear originally, I had a small amount of toe-in. The airplane was quite unstable on the ground. After research, I shimmed for a small amount of toe-out and the airplane became a "pussy-cat"!
Also if you look at the standard RV gear attached to the engine mount, the standard set-up is for straight ahead without weight on the gear. Now, because of the gear design, when you apply weight to the gear, the wheels will actually toe-out slightly as the gear spreads.
BTW, before you "A" drivers jump in, a tricycle gear configuration is entirely a different matter.
__________________
Mel Asberry, DAR since the last century.
EAA Flight Advisor/Tech Counselor, Friend of the RV-1
Recipient of Tony Bingelis Award and Wright Brothers Master Pilot Award
USAF Vet, High School E-LSA Project Mentor.
RV-6 Flying since 1993 (sold)
<rvmel(at)icloud.com>
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07-05-2012, 09:48 PM
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Join Date: Jul 2008
Location: Santa Rosa, CA
Posts: 580
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No springs at all
When I had my RV 4, I removed both springs on the tail wheel and it worked perfectly except for one thing. Taxiing in a X wind contributed a lot to brake wear. To save my brakes the springs are back on.
Steve
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07-05-2012, 09:50 PM
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Join Date: Feb 2005
Location: Bay Pines, FL (based @ KCLW)
Posts: 1,955
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Quote:
Originally Posted by Mel
Think of it this way; if you have toe-in and you begin to swerve left, centrifugal force places more weight on the right wheel. If this wheel is toed-in, it will cause the aircraft to swerve MORE to the left. On the other hand if the wheel is toed-out slightly, it will cause the aircraft to be pulled straight.
I know there is a lot of controversy on this subject, but when I built my gear originally, I had a small amount of toe-in. The airplane was quite unstable on the ground. After research, I shimmed for a small amount of toe-out and the airplane became a "pussy-cat"!
Also if you look at the standard RV gear attached to the engine mount, the standard set-up is for straight ahead without weight on the gear. Now, because of the gear design, when you apply weight to the gear, the wheels will actually toe-out slightly as the gear spreads.
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Mel,
I've not measured my toe-out with the gear hanging but it appears to be toed out quite a bit. I've only done taxi testing right now but there appears to be some scuffing on my right tire.
How did you shim out to correct to achieve a toe-out? From the engine mount? I would like to remove some toe-out.
__________________
Danny "RoadRunner" Landry
Morphed RV7(formally 7A), N20DL, PnP Pilot
1190+ hours
2019 Donation Paid
Last edited by roadrunner20 : 07-05-2012 at 09:54 PM.
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07-05-2012, 10:58 PM
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Join Date: Oct 2009
Location: Victoria, BC, Canada
Posts: 3,932
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A second rocket link won't help you because you can probably already overpower the locking pin on the tailwheel with one link. A second one would just add weight.
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Rob Prior
1996 RV-6 "Tweety" C-FRBP (formerly N196RV)
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07-06-2012, 04:51 AM
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Join Date: Jan 2005
Posts: 269
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Mel,
What is the best way to check for toe in toe out?
__________________
Adam Silverstein
Technical Counselor Chapter 643
Flying RV-8 10/30/07
PAID 2021
Pittstown, New Jersey
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