Jabiru main landing gear question

[PureCaboose]

Taking off yesterday (after 2 touch and goes) from a full stop I head a clunk under my seat, immediatly cut throttle and put her back down on the runway (I have 1.4km to use).

 

Taking off the  covers over the main landing gear I note that the left hand rubbers are pretty much done, so easy, order new ones and replace (and do the 500 hr update while I am there).

 

My questions is, on the right hand side there is a white spacer that sits above the inboard bolt, about 10mm in height. It is only on the right hand side, the left hand is hard against the floor. 

 

I can't see this spacer in the Jabiru Technical Manual for the J160 airframe. 

 

Reaching out to the brainstrust here, is this supposed to be there? Should there be one of the left hand side as well or should I remove it when I replace the rubbers?

 

I am going to do a wheel alignment when I finish as I am chewing out the outside of the tyres on the main gear as it is.

 

PureCaboose

J160

[skippydiesel]

Hi PureCaboose,

 

If you are located at YMIG, as your details suggest, you should know that you have no less than two very experienced Jab maintainers at The Oaks, who I am sure can answer your question with the appropriate authority. 

 

Contact me through the personnel system, if you would like to proceed down this path.😈

 

[PureCaboose]

I am in YMIG, and I use John from the Oak for everything that is beyond me (for now).

 

Part of owning my own plane is expanding my knowledge and experience. In the technical manual there is no spacer, so i am curious as to why it is there, and who put it there now that I think of it as the plane has been L2 maintained to date.

 

Building a platform/brace for the engine hoist so I can lift the wing to get the gear off. New brake disks to go on and balance the very much out of balance wheels.

 

If I can't work it out, I will call John. I though I would asks here to what knoweldge there was. My bad.

 

PureCabosoe

[Blueadventures]

15 minutes ago, PureCaboose said:

I am in YMIG, and I use John from the Oak for everything that is beyond me (for now).

 

Part of owning my own plane is expanding my knowledge and experience. In the technical manual there is no spacer, so i am curious as to why it is there, and who put it there now that I think of it as the plane has been L2 maintained to date.

 

Building a platform/brace for the engine hoist so I can lift the wing to get the gear off. New brake disks to go on and balance the very much out of balance wheels.

 

If I can't work it out, I will call John. I though I would asks here to what knoweldge there was. My bad.

 

PureCabosoe

You could send images to Jabiru and ask about this, as if you need any other parts they can be sent with the rubbers. Would be a shame if you need two postage’s and await a second delivery. Great that you are getting to understand your aircraft’s build. Let us know what you find out. Cheers.

PS never know may have only had an over length bolt. If so you will need a correct length one.  Just a guess.

Edited July 15 by Blueadventures

[skippydiesel]

1 hour ago, PureCaboose said:

I am in YMIG, and I use John from the Oak for everything that is beyond me (for now).

 

Part of owning my own plane is expanding my knowledge and experience. In the technical manual there is no spacer, so i am curious as to why it is there, and who put it there now that I think of it as the plane has been L2 maintained to date.

 

Building a platform/brace for the engine hoist so I can lift the wing to get the gear off. New brake disks to go on and balance the very much out of balance wheels.

 

If I can't work it out, I will call John. I though I would asks here to what knoweldge there was. My bad.

 

PureCabosoe

ALL good!

There was a wing lift devise,  at The Oaks, a few weeks back, being used for the very work you describe.😈

[PureCaboose]

Ordered the bolt and rubber kit, and there is a new kit for fastening the cowls back onto the fusilage.

 

Going to do a wheel alignment when they go back on, as well as learning how the balance the wheels after I swap the tyres around on the rim.

 

 

[facthunter]

I can only suggest that is a  spacer and the stud/bolt is too long. Balance the wheels on level knife edges on a suitable mandrel. Some of those Jabiru wheels have excess Camber. I think that is corrected by a wedge. Jabiru used to have a lot of this stuff on Line.  Nev

[PureCaboose]

56 minutes ago, facthunter said:

I can only suggest that is a  spacer and the stud/bolt is too long. Balance the wheels on level knife edges on a suitable mandrel. Some of those Jabiru wheels have excess Camber. I think that is corrected by a wedge. Jabiru used to have a lot of this stuff on Line.  Nev

I though it was a spacer, however it is on top of the inner part of the leg spacing it down from the bottom of the frame. This would cause the outer part of the leg to move further out, and make the vertical mount for the hub either more vertical, or more camber. It has been suggested that it is for wheel alignment instead of spacers and flocking at the hub side of the leg.

 

I need to move around the hanger mate aircraft before I take when wheels and legs off otherwise i will block the hanger access.

 

I have the build and technical manuals for the J160, I will be doing a pre and post wheel alignment settings to see what I have currently, and what I end up with after I am done. Hopefully I can reduce the tyre wear on the outer edge, and tone down the twitchiness when on the main gear and high speed rolling (take off and landing)

[MikeBravoYanky]

Can I get tech manuals for the Mk4 single seat Jabiru Supapup? I would like to know how the main undercarriage camber is set/checked..

[PureCaboose]

New parts have arrived, the rubber bushings are now red nolethane bushes. Even got a few baggies with machine screws and the little  screw in fittings for the fusilage to hold on th fairings.

 

Moved the planes around in the hanger, just working on how I am going to move the engine hoist to the airfield.

 

Interior is out, and I have found all the interior nuts I need to remove.

 

sitting ataround 360kg (empty plane with fuel) there is 2 degrees of positive camber 

 

Planning on getting some time next week (perhaps tomorrow) to go and make a start on this.

 

Need to remember to get 5min apoxy glue on the way.

 

Caboose.

[T510]

18 hours ago, MikeBravoYanky said:

Can I get tech manuals for the Mk4 single seat Jabiru Supapup? I would like to know how the main undercarriage camber is set/checked..

I have a Nostalgair Supa Pup and have the manuals for it, not sure it is the same as a Mk4 Supapup though

[facthunter]

Camber doesn't matter much. A bit of toe OUT helps a Taildragger at touchdown.  Nev

[PureCaboose]

36 minutes ago, facthunter said:

Camber doesn't matter much. A bit of toe OUT helps a Taildragger at touchdown.  Nev

I need to even the tyre wear, the outside edge of the tyre is amost done and the inside edge is hardly worn.

 

You can't see if with the spats on, but with them off it looks like it is sitting up on its toes when empty, the 2 degrees each side is visible. I am not sure what the toe is, have to get a longer piece of angle to check it.

 

PureCaboose

[facthunter]

Wedge it at the wheel if you want to. Excess toe in will make it wear also. Scrubbing. Rub the Palm of your hand across each tread to see if it's like a rip saw tooth effect. Nev

[MikeBravoYanky]

2 hours ago, T510 said:

I have a Nostalgair Supa Pup and have the manuals for it, not sure it is the same as a Mk4 Supapup though

Is the undercarriage triangular with spring sliding tubes and is it adjustable in any way?

[PureCaboose]

1 hour ago, facthunter said:

Wedge it at the wheel if you want to. Excess toe in will make it wear also. Scrubbing. Rub the Palm of your hand across each tread to see if it's like a rip saw tooth effect. Nev

Depending on what is going on, I will look at the wedge and flock method at the hub base on the outboard end of the leg.

[PureCaboose]

20 minutes ago, MikeBravoYanky said:

Is the undercarriage triangular with spring sliding tubes and is it adjustable in any way?

It's multi-layered fibreglass bent into a radius during the layup. two legs, each bolts to the bottom of the fusilage under the rear of the seat base and the then bends down in a radius to the hub mount.

[MikeBravoYanky]

1 hour ago, PureCaboose said:

It's multi-layered fibreglass bent into a radius during the layup. two legs, each bolts to the bottom of the fusilage under the rear of the seat base and the then bends down in a radius to the hub mount.

Ok not a Cub style of aircraft.. mine is steel tube fuse and undercarriage.. Thanks..

[skippydiesel]

Hi PC,

 

"It's multi-layered fibreglass bent into a radius during the layup. two legs, each bolts to the bottom of the fusilage under the rear of the seat base and the then bends down in a radius to the hub mount."

 

Speculation:

 

• You may be able to shim the leg : fuselage inside bolts, to change the camber.
• Toe will either require a special angled shim on the axle: leg OR you may have to elongate two or more leg : fuselage  mounting holes to get sufficient movement  to effect an adjustment.

😈

[PureCaboose]

5 minutes ago, skippydiesel said:

Hi PC,

 

"It's multi-layered fibreglass bent into a radius during the layup. two legs, each bolts to the bottom of the fusilage under the rear of the seat base and the then bends down in a radius to the hub mount."

 

Speculation:

 

• You may be able to shim the leg : fuselage inside bolts, to change the camber.
• Toe will either require a special angled shim on the axle: leg OR you may have to elongate two or more leg : fuselage  mounting holes to get sufficient movement  to effect an adjustment.

😈

The factory method is to space the hub out with washers to get the camber and toe requried, then flock them into place. 

 

It's a factory (24 rego) aircraft, so I wonder what I will find when I pull it apart.

 

Might take some photos and video of my tasks as I go for future reference.

 

PureCaboose