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Thread: New landing gear tracking?

  1. #41
    Steve Pierce's Avatar
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    I have a gear jig. Factory gear drops right in it and the bolts push right in. I also have a set of heavy duty Univair Super Cub gear. If either one can help you let me know.

    Just something to throw out there, fuselage fittings bend easily and not all new fuselages are straight.

    They said some one must have made a hard landing in my plane and damaged the fuselage. Not likely as it was built with an Alaskan modification to strengthen the gear attach points and the entire fuselage is 4130.
    The only gear fitting mod I know of is the heavy duty front fittings and those are from Airframes.
    Steve Pierce

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  2. #42
    hotrod180's Avatar
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    Quote Originally Posted by RCharles View Post
    Talked to Univair today and they assured me that the jig they use is spot on......
    Would you expect them to say anything else?
    Cessna Skywagon-- accept no substitute!

  3. #43
    RCharles's Avatar
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    Quote Originally Posted by Steve Pierce View Post
    If you have a way to hoist the airplane or even if you don't use long bolts in the gear and then measure between the front gear attach bolts and the rear attach bolts and make sure your fuselage at the gear fitting is square. Gear fitting can get tweaked just like gear.
    OK,Checked the gear attach points and all spot on. Also checked the left gear leg by running a laser light down the front of the left forward gear leg and out the axle as suggested by the Univair folks and the axle is out of alignment so far that the laser point is not visible on the end of the axle. Showing a large toe out that confirms all our other tests.Doing the same test on my old gear the laser line runs straight out the center of the axle showing that the axle has no toe in or out but is straight tracking as it should be and like Univair claims their jig to be set.They have not once in all our conversations mention that there is a chance the jig they used is out of alignmemt .Up to this point they have been trying to tell me that the plane has been through a hard landing and the fuselage is bent or some other problem that has caused this.Maybe even damaged in shipment? Really? Be careful folks and I have learned my lesson and do not have some one cover your gear until you have checked them out mounted and tracked .
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  4. #44

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    First, once you present them with actual evidence, I am sure they will make it good.

    Second, the laser idea sounds great. Tell us more - you align the pointer along the forward edge of the gear leg and look for parallel? How does the pointer disappear behind the axle? Can you post the photos that you will send to Univair, showing the laser test?

    Hot digs - I am testing my spare gear leg as soon as I figure this out! Mine may have been tweaked during a horrific ground loop - very faint wrinkes in the fabric. Other side was demolished, so we replaced both. Not my airplane; I just did a lot of the work.

  5. #45
    RCharles's Avatar
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    Place the laser on the top of the forward gear leg and shoot down the center of the tube. The axle is just an extension of the forward gear leg.Now you will have to jockey the laser here a little to get it onto the axle but you will see how it will run straight on out the the center of the axle if it is jiged at zero degrees no toe in or out.I think this is a fool proof way to tell what you have.I wanted to take a video of this but do not know haw to post it .If that line is left or right as it goes out the axle you will see whether it is toed left or right iE forward or back from roughly 90 dgrees in relation to the center line of your plane...Now you must have the weel assembly removed...
    Last edited by RCharles; 05-26-2021 at 03:46 PM.

  6. #46

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    Got it! I shall try tomorrow. I will take the camera. Neat! Thank you!

  7. #47

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    I tried with a pointer. The torque plate flange stops the laser (of course). Then I stretched a string and sighted down that. Looks ok.
    Apparently there are lasers that are planar, as opposed to "spot." That is probably what Univair meant, but I would guess there is more to it than just turning the laser on. It would have to be clamped exactly vertical.

  8. #48
    supercrow's Avatar
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    I use a laser mounted on a tripod and fully adjustable for laying out straight lines for painting. It can lay a vertical or horizontal line or anything in between. Would work great for this gear examination.

  9. #49
    Steve Pierce's Avatar
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    Here is the best way I know how to check gear alignment.
    Attached Files Attached Files
    Steve Pierce

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  10. #50
    RCharles's Avatar
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    1.We have determined that the left gear is toed out and the right is toed in.
    Measured at 70 inches ahead of the wheel the left is about 2 3/8 inches further from the center line than the right wheel.
    2 .The right wheel is toed in very slightly at about 1/2 inch we think and that is ok.
    3.I am gong to jig the new left gear before removing it and then see if the old gear will fit in that jig.I expect that it will not. If it does then I will be sure we have entered the "twilight Zone" ....
    4.The old gear will be hung from the same mounts that the new just came off of and have flown on the airplane for 1300+ hrs without pulling to the left!
    5.I plane to then return the gear Univair and request that they replace at least the left gear that is jigged true and straight.And I will verify same before I cover it!
    Last edited by RCharles; 06-14-2021 at 03:19 PM.

  11. #51
    RCharles's Avatar
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    well here is the latest info I have on my tracking problem , I shipped my new gear and my old gear to univair as they requested and they ,after putting my old gear in thier jig, said that it did not fit, and basically that I was SOL.This is what the said
    Your original gear.
    "Axle is bent toe in

    The main tube in line with the axle measuring from the holes where the long strut attaches to the hole in the forward gear attach is 1/8” longer which would affect the camber of your axle.
    This gear we are unable to put in our jig due to the above issues. The top attach bolts are in line the same as our gear. We are guessing that maybe someone has adjusted the axle or maybe this gear has been worked on in the past? Our inspector also said maybe the gear attach fittings could have been welded a bit off and it wouldn’t take much to need that axle to be adjusted".
    nivair gear.
    "With the fabric on the gear still slides right into the fixture we have been manufacturing them in since the mid 60’s.

    Axle and main tube are both in line with no toe in or toe out.
    Both the Piper original drawing and the Univair prints call out the leading edge tube and the axle to follow the same center line.

    So to answer your statement of our gear being toe out, compared to your gear with being toe in and different camber and our gear being neutral it would look toe out. The bad news is that Univair would not be able to make a gear to fit your needs for your aircraft as we would have to build it not using a jig and then it would not be able to be certified since it would not conform to a Univair print or Pipers gear print. You might look at the gear fittings as our inspector had mentioned as you said you have toe in on the right and toe out on the left something seems a bit off and with as much as your gear is tweaked at the axle it was adjusted at some point in time.

    Sorry this is probably not the answer you want to hear but I do want to thank you for sending in your gear as well so we can see where the problem may be at. Like I said over the phone we sell these gears for the cubs and have done so for many years using the same jig and prints since 1967. With how many we sell of these gears there would be receiving a bunch of negative feedback if there was a manufacturing issue."

    SO,I have two landing gear [left side] that came off of 1954 model L21B aircraft.One off of my plane and another from a friends airplane that are basically identical and are tracking almost straight.
    I have been flying the airplane for over 25 years with the gear that they were sent along with the new ones I just purchased them .The problem with controlling the plane on landing started with the new gear installation. All the mounting points are spot on!
    SO, at some time in the past piper aircraft must have changed the jig configuration.If anyone with a 1954 or early cub purchases one of these gear they are not going to be toed probably .It is highly unlikely that I have the only two gear that are different...Comments welcome please ?
    Last edited by RCharles; 08-15-2021 at 06:30 PM.

  12. #52
    Steve Pierce's Avatar
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    Blast, inspect and recover your gear and install it. We jigged several L21 fuselages in my jig and they fit perfectly. We also installed a few sets of Univair gear on said L21 without issue. I would suspect your fuselage might have gotten tweaked over the last 67 years.
    Steve Pierce

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  13. #53
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    Steve ,thanks for the post. but, I had this fuselage built for me by Jim Soares at Rocky mountain Airframe in 1994and at that time he was building frames for Univair. If you ordered a piper super cub fuselage at that time it was built by him.When I recieved the finished product in Atlanta I had the airplane restored complete with new fabric,cables, wiring,etc,all except landing gear.It was the original gear as far as I know.
    I also have another set of gear from a 1954 L21B like mine and it's left gear test on my plane near perfectly straight like my old gear that univair is talking about that I sent them along with the new gear that is different.The 1954vintage gear looks to be from a slightly different jig.
    Now univair bought Rocky mountain at some in the past after Mr. Soares passed away. I have heard that univair bought the jig and many of his tools.Anyway Any body who purchased a frame from piper back then got one just like mine made by Jim Soars I think.I have checked the frame and it is fine!

  14. #54
    Steve Pierce's Avatar
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    Take 2 3/8" rods, sharpen one end of each to a point and slip them into the two gear attach fittings and measure the distance from the front and rear.
    Steve Pierce

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  15. #55

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    One thing I would not do is cover whatever gear you decide to use until you have put it on the plane and make sure it works.
    Denny
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  16. #56
    RCharles's Avatar
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    We have run a 15/16th rod thru the attach lugs and they are very straight .A 3/8 rod is a bit tight.All three gear we have . have mounted easily.The left hand leading edge upper bolt is the only one that the bolt needs a little coaxing in each case.
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  17. #57
    Gordon Misch's Avatar
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    Quote Originally Posted by RCharles View Post
    We have run a 15/16th rod thru the attach lugs and they are very straight .A 3/8 rod is a bit tight.All three gear we have . have mounted easily.The left hand leading edge upper bolt is the only one that the bolt needs a little coaxing in each case.
    Not what Steve is suggesting. He is asking you to check gear lug parallelism between the two sides on your fuselage.

    Edit: And even if the two sides are parallel to each other, they might not be parallel to the horizontal reference line per the Piper prints. Please report back what you ultimately find!
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  18. #58
    RCharles's Avatar
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    Gordon,This frame was built in 1994.When I got it I mounted the gear from my plane built in 1954 and flew it for over 25 years that way ..The only thing that has changed is the new univair gear.When you put these new univair gear next to the older piper gear there is actually a difference in the length by 3/8 inch .?

  19. #59

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    Go back to my post #36! Your fuselage has been around since 1994, lots of things may have happened in that time. Verify the location of all the fuselage gear fittings for parallelism and location for and aft. With the fuselage level, drop a plumb line (or laser) down to the floor from the centerline of each fitting, and make your center line from the firewall to the tail post. Measure from the center of the fuselage to each fitting and verify they are all the same. Then measure the diagonal from left front to right rear, and then from right front to left rear. Those measurements should be the exact same, or your fuselage fittings are off. Don't forget to also check the cabane attach fitting locations as well.

    Get the drawing for the gear and verify the measurements for the gear if you don't believe Univair. If the gear is correct, then the only thing that can be wrong is the fuselage.
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  20. #60
    skywagon8a's Avatar
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    How do your new and old gears compare to this drawing?

    http://www.supercubproject.com/drawi...s/A3310136.pdf
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    N1PA
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  21. #61

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    Quote Originally Posted by Bearhawk Builder View Post
    Don’t want to heat it? Trust me it’s the only way to bend that cluster.
    5' schedule 40 pipe will move a very big cluster without heat...
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  22. #62
    RVBottomly's Avatar
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    Quote Originally Posted by astjp2 View Post
    5' schedule 40 pipe will move a very big cluster without heat...
    Have you tried that while attached to the airframe? I have significant toe-in on my airplane (not a cub) and I was reluctant to remove the fabric and take a torch to it.

  23. #63

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    Quote Originally Posted by RVBottomly View Post
    Have you tried that while attached to the airframe? I have significant toe-in on my airplane (not a cub) and I was reluctant to remove the fabric and take a torch to it.
    I have done 4 taylorcraft that way, similar gear configuration and had several people help hold the plane still along with tiedowns. Wheels are removed and the axles are sitting on jackstands right next to the brake plates. Pipe over the end and a good reef. My tcraft is 1\8" toe in at 1 8 " forward of the axle centerline. All of the others I did are about the same. Some will scream that you have to use heat, maybe on super heavy-duty gear, but no cracks have been found get on the ones I did. Good luck
    Tim
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  24. #64
    RVBottomly's Avatar
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    Quote Originally Posted by astjp2 View Post
    I have done 4 taylorcraft that way, similar gear configuration and had several people help hold the plane still along with tiedowns. Wheels are removed and the axles are sitting on jackstands right next to the brake plates. Pipe over the end and a good reef. My tcraft is 1\8" toe in at 1 8 " forward of the axle centerline. All of the others I did are about the same. Some will scream that you have to use heat, maybe on super heavy-duty gear, but no cracks have been found get on the ones I did. Good luck
    Tim
    Thanks. My Commonwealth has a similar configuration. I measure 1/8" toe-in both sides at 12 inches. It's noticeable when you roll it backwards 10 or 20 feet and the gear splay out maybe almost two inches.

    I think that is the only thing keeping me at borderline "possessed" instead of "pussycat" on pavement.

  25. #65

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    Quote Originally Posted by RVBottomly View Post
    Thanks. My Commonwealth has a similar configuration. I measure 1/8" toe-in both sides at 12 inches. It's noticeable when you roll it backwards 10 or 20 feet and the gear splay out maybe almost two inches.

    I think that is the only thing keeping me at borderline "possessed" instead of "pussycat" on pavement.
    Mine is half of yours, I would adjust it. The slight toe in compensates for weight of people bags and fuel so it doesn't splay out when taxiing or landing. I experimented to figure it out. 0 toe looks good on paper but not in practice for some aircraft. Tim
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