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Old Aug 26, 2011, 05:59 AM
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Birmingham, UK
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Help!
Nosewheel steering for retracts

I'm building a Crescent Tornado (mine's from an original 70's kit), a 60 size trike UC model, which I'm kitting out with mechanical retracts - mechanical because that'swhat I've got to hand. The Tornado is the ususal sort of slim nose 70-80s job with a sidewinder motor and a nosewheel bay under the tank.
The retracts I'm using are Irvine brand where the steering link is a single sliding 'ear', so it's a pushrod job. The retract will screw to a 1/4" ply plate under the tankbay floor. What's the best way of connecting up a pushrod, what works for you guys? Would I be best to use a seperate steering servo or just hook it up to the rudder servo? There's not enough room in the wheel bay for a seperate servo to fit up close so it will have to be a pushrod or snake from the wing bay.
Any help and guidance will be appreciated.

Bob
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Old Aug 26, 2011, 11:17 AM
R_G
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Here's how I did it on my current UFO build: http://www.rcuniverse.com/forum/fb.asp?m=10603214

I haven't got to the servo end yet, but I plan to attach the pushrod to the rudder servo. I had thought about a separate servo, but decided to save a little weight and just use the rudder servo.

Ralph
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Old Aug 26, 2011, 01:23 PM
Raised on 80's Pattern
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Here is some pictures of the steering on my Atlanta. I used a Tetra Tech Flex Rod to get from the upper fuse to the bellypan/retract area. This has worked well for many years. (I do no know if these are still available.)

I previously had the flex rod attached to the rudder servo. When the plane was recently brought back to life we added an extra servo specifically for steering. I small servo is light and works fine. This steering servo was put on channel 7 and mixed to slave to channel 4 (rudder). The benefit of this system is the abailityto independently adjust each control and to easily trim the steering without effecting the rudder.

Good luck and let me know if you have any other questions.

Doug
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Old Aug 26, 2011, 01:51 PM
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Thanks Gents, the Irvine unit steering arm is very similar to Doug's. I guess either a snake or bowden cable will be ok as long as the outer is held rigidly as near to the retract as possible and in line with the pivot.
It looks as though the pushrod alignment provides some centring of the wheel as it retracts, is that right?
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Old Aug 26, 2011, 02:23 PM
Raised on 80's Pattern
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No. There is a spring on the front of the retract (The MK, that is) that centers the wheel while it is retracted.

You can see it in the picture of with the two screws holding it in place.

Doug
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Old Aug 27, 2011, 03:11 AM
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Cheers Doug, I see it now. I'm sure I can come up with something along those lines to do the job.
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Old Aug 27, 2011, 09:26 AM
R_G
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I need to do something like that also. The Springs Air nose gear in my UFO has an issue with rotating as it retracts. A centering spring like that on the MK gear would solve that problem.

RG
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Old Aug 27, 2011, 10:37 AM
Raised on 80's Pattern
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Glad Japanese engineering can help! i take no credit!
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Old Sep 03, 2011, 05:12 PM
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Quote:
Originally Posted by R_G View Post
I need to do something like that also. The Springs Air nose gear in my UFO has an issue with rotating as it retracts. A centering spring like that on the MK gear would solve that problem.

RG
The Spring-Air nosegear should have a short music wire "spring" that attaches to the front of the trunnion block and sticks up thru a hole in the steering plate in front of the wire strut. Check it out, yours may be missing.
This feature is basically copied from the Rohm Air nosegear.

-Robert
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Old Sep 03, 2011, 05:48 PM
R_G
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Robert,

There's nothing like that on my nose gear. No provisions for it either and the Spring Air web site doesn't anything type centering device. Seems like this is something that should be a standard item for all nose gears. Robarts web site also doesn't show any type center spring on their nose gears. At least I couldn't find one.

RG
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Old Sep 03, 2011, 08:06 PM
R_G
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OK Robert, I just noticed in your "Phoenix 7 ARF Retract Retrofit" thread that you have cable steering as opposed to "single steering". I poked around the Spring Air site a bit more and found that their 700 series retracts offer cable steering with the centering spring hole in the steering arm. That must be what you are using? I have the 200 series which are only offered as "single steering".

RG
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Old Sep 03, 2011, 10:49 PM
Paul Pappas AMA 42520
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Ralph, I think you only get the centering pin with cable steering and not with the pushrod steering.

Robert I believe is using the low profile 300 series (302’s), in the pic you can see the boss and pin.

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Here is a 100 series nose gear (102’s) and centering pin.

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I think this part might be #129 Centering Wire Retainer.

.
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Old Sep 04, 2011, 05:34 AM
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Birmingham, UK
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I looked at the Irvine noseleg I'm using, but there's no room to fit a spring. I think it should be ok though, as I've used a Sullivan snake for steering with a wire stiffener in the inner, and the outer glassed to a balsa block close to the retract. All this means the clevis is located exactly on a line with the leg's pivot so centres the wheel as it retracts, even with full steering applied. It will be interesting to see how well the plastic parts of the retracts stand up to use, they are sold as suitable for 60 size but GRP, nylon or other plastics always make me nervous in high-impact locations.
Nearly time to start covering!
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