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

[PureCaboose]

None of the supplied bolts are long enough, spoke to Jabiru and I was sent 26a and 27a bolts. But I might need 31a, 32a or 33a bolts.

 

Now I need to take them all out, measure them and ask for the right bolts.

 

This is a 24, factory built aircraft that even the manufacturer can't supply off the shelf parts for. And I have $120 worth of toolbox fillers that I can't use.

 

I love my Jabiru, don't get me wrong. But between nothing being 'factory' and the poor paint quality I am beginning to thing I got a last friday of the month plane.

 

Now I just need another day to head out to the airfield, jack up the plane and take all the bolts back out, measure them, put them back in and wait.

 

PureCaboose

 

[facthunter]

Maybe your set  up is not standard? How many previous owners?  Nev

[PureCaboose]

2 previous owners, full(ish) maintenance records. It has not had the 500 hrs bolts done in the 1100(ish) hours it has flown.

 

The black, rubber bushing on the inboard end were falling apart (hence the clunk that alerted me).

 

There is a number of things that have me going WTF on this plane, it has a transponder that is not run through the avionics switch, just the main switch, the transponder and radio are sitting in a timber panel that is siliconed, screwed and pop riveted to the panel. The cover of the elevator horn and trim command was held on with machine screws into the threaded inserts, wood screws, plasterboard screws and builders adhesive. I had to cut if off the plane once all the screws were out.

 

I has been sitting outside on the hardstand on a coastal airport for a few years, it has pumpkin head cover the windows etc are good but anything that is not stainless, non-ferros or composite has a patina on it. I will be doing a full fastener replacement and bolt inspection later this year. We pulled the control surface bolts for the annual earlier this year and they are all good, no sholders etc just discoloured by salt spray.

 

It's a 2011 factory build 160, with the dual brake calipers. It does need (and I have them) the disk replaced as they are are a pitted nightmare due to the salt exposure, but they still work. I am going to referbish the whole brake, axle, wheel, tyre, spat assembly.

 

PureCaboose

[facthunter]

Thanks for that. Good luck with it. You should get  there eventually..  Salt I DON'T like. Nev

[MikeBravoYanky]

Thanks everyone my L2 removed the sprung legs and re-drilled and reamed new bolt holes at the top centre connection point to bring the wheels back to upright. Ready for test flight just waiting for registration certification..