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Thread: Wheel Alignment

  1. #1
    Senior Member jiott's Avatar
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    Default Wheel Alignment

    I am just completing a SS7 with the Grove aluminum spring gear. I have seen some good threads on this forum for checking wheel alignment (toe-in, toe-out) but it is a somewhat involved procedure. I am wondering how necessary is this on the Kitfox Grove gear? Is there a reasonable liklihood that the wheels will need some shimming, or is the brand new Grove gear made consistently accurate enough that the alignment procedure is just busywork? I understand the need to do this if you have had an incident where the gear could have been tweaked. What have you guys done?

    Jim

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    Default Re: Wheel Alignment

    ours was spot on with no shimming needed.

  3. #3
    Senior Member HighWing's Avatar
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    Default Re: Wheel Alignment

    Jim,
    I had the bungee gear on my first Model IV then switched to the Hammerhead gear rather than the Grove - The two companies were once partners like Avid and Kitfox. The bungee gear was severely toed in as I think they all were, but the aluminum gear was fine. That said, there is a pretty easy way to do a rough check on the alignment. Put a piece of tape on the exact aft - axle height - center of each tire. Make a vertical line with a pen on each and measure the distance between the marks. Also measure the distance between the two gear legs. Roll the airplane forward so the marks are now at axle height on the forward side of the tire. Measure again between marks and measure again between the gear legs. Then compare the differences of the two measurements. Here it may get confusing, but if the measurements are similar, you should be tracking fine. If the marks on the tires are closer together and the gear legs are as well, you likely have some toe in. If both measurements are longer, it would mean that you likely have some toe out. If one measurement is in and the other one is out, forget you read this post as I don't have a clue on that outcome. If both are significantly in our out, you might want to do the follow up hard part. Not being too clear on decades old Trig, I drew the measurements onto a cad program and it gave me the angle of deviation - this of course relative to the axles only with no info as to which axle is bonkers or how it tracks relating to the long axis of the airplane.
    Lowell

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    Senior Member Geowitz's Avatar
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    Default Re: Wheel Alignment

    I would imagine it will be pretty close to straight, but really, checking toe in/out can be pretty easy. See my post on the thread below. It takes 2 pins, a level spot, a tape measure, and 3 minutes. Similar to Lowell's thoughts, but practically I take this as the actual measurement. You can figure out the degrees with a little geometry/trig. I have about .8 degrees toe out on each wheel. Ground control seems great.

    http://www.teamkitfox.com/Forums/sho...hlight=geowitz

    * Roll the plane forward for 10 feet or so to settle the gear as it would sit when rolling in an actual taxi/take off. Then measure in the back. Roll forward and measure in the front. If you want to get real technical you can get someone to sit in the plane so you can see what it is at flying weight. Perhaps with tail up in flying position as well as toe in/out will change from 3 point to tail up config.

    Just my way of doing things and it seems to be working great.
    Last edited by Geowitz; 01-09-2013 at 07:39 PM.

  5. #5
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    Default Re: Wheel Alignment

    good morning all, i think the imporant thing on this subject is how does the air plane taxi. the only thing we can ajust on the grove gear would be toe in with shims on the spindls as the caster is fixed and the camber is built in to the gear and changes with load on the gear.
    that being said the toe is very imporant to how the airplane tracks, when setting up the front end of a race car we had to find the best set up for the driver taking into consideration caster, camber, settings, bump steer, shock travel, ackerman, just to name a small list of things to consider. we would ajust the front end of the car for each track but no mater were we went, short track or super speedway we always made sure the toe was set out. on a short thack we ran 1/8 " toe out. on a super speedway we shot for 1/16" toe out but if the driver complaned about the car wandering down the straight away we would add more toe out. that being said if the airplane tracks good i would leave it alone. if it wants to wander add more toe out after making sure every thing else is right, air pressure, no draging break. ect. my two cents worth. hope this helps.

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    Senior Member jrevens's Avatar
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    Default Re: Wheel Alignment

    The camber can be adjusted as well as the toe in with the same type shims. While it may not usually be necessary with the Grove gear, it can be easily done if desired or needed. Most airplanes are all a little different, but I also know that my personal experience with my first homebuilt, a taildragger that I've been flying for over 22 years, is that neutral alignment (or no toe-in or toe-out) is definitely best. The Kitfox lands a lot slower and is definitely more benign, but the Thorp T-18 can be an amazing handful if the alignment isn't correct. Adjust it to neutral and it's a *****cat. Additionally, your tires will last longer.
    Last edited by jrevens; 01-10-2013 at 02:44 PM.
    John Evens
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    Senior Member jiott's Avatar
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    Default Re: Wheel Alignment

    What I am really trying to determine is how many of you with the Grove gear actually found you needed to shim to get correct toe-in/out?

    From the responses so far it seems several of you checked, but nobody (maybe Geowitz) actually did any shimming.

    Jim

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    Super Moderator Av8r3400's Avatar
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    Default Re: Wheel Alignment

    No shimming for me...
    Av8r3400
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    Senior Member SkySteve's Avatar
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    Default Re: Wheel Alignment

    Bolt on and fly.
    Steve Wilson
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  10. #10
    Senior Member Geowitz's Avatar
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    Default Re: Wheel Alignment

    Yeah, I shimmed because I had 1 degree of toe in.

    In case anyone was wondering my reason... There are different schools of thought, but I erred towards the toe out camp. The thought being, in a developing ground loop situation where weight is transferring to the wheel to the outside of the direction of the swerve, a wheel at toe in will exacerbate the ground loop because it is getting more traction to steer more into the swerve. In the same situation of weight transfer and increasing traction toe out would help to fight the ground loop.

    However, the grove flexes quite a bit and having the wheels straight will actually give you a little toe out under forward stress.
    Last edited by Geowitz; 01-10-2013 at 08:16 PM.

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