Anyone Out There?

[BigPete]

C'mon Guys and Gals,

 

where are all the Jabiru posts? - It's far too quiet.

 

OK - I'll ask a question.

 

My poor little J160c has severe toe in. Looks like its trying to cross its legs so as not to pee.

 

So I have to make up some wedges, but how much toe-in do I need?

 

regards

 

 

[blueline]

No idea about your toe in problem, but where are the Jabiru fans? - too busy flying!

 

 

[theoy]

Hi Big Pete

 

As your Jabiru is a factory built it might be a good idea to get Cliff Banks L2 from Swan Hill to do the job.

 

Cheers Theo

 

 

[Wilfred]

Just a thought

 

Put a full load in your Jab : Full Fuel and pilot & passenger, then wheel it along a few feet and have a look then. You will more than likely find that the problem is not there once there is a bit of weight on the suspension

 

Peter

 

 

[old man emu]

Hmmmm.

 

Sounds like your Jabiru is pigeon-toed!

 

Old Man Emu

 

 

[glenns]

Pete, I have the same problem with mine. There has been lots of talk in our club about this. One of the schools fo thought is that the undercarriage they have used on the 160 is actually meant for 700kg and is the same as the 230. Hence unless you have full weight in the aircraft they will tow in. Having said that I have also discovered what appears to be an inconsistancy in the undercarriage on my aircraft. It looks like one of legs were not cleaned up correctly after being removed from the mold and this has caused excessive toe in on the passenger side to add to the problem. I have planned via an engineer to have a look at this and some adjustments.

 

I will take a photo next time I am at the field so you can see what I am talking about.

 

 

[Guest brentc]

You're referring to 'camber' rather than toe-in I would suggest. To fix this you'd need to take off the stub-axles and pack them out with some washers at the bottom, then fill the void with fibre-flock / resin. There's a few hours work here for someone in the know. Ask me for more info if you wish. There's not many downsides to this other than having to reverse your tires when they wear unevenly. It's a pretty common problem unfortunately.

 

 

[Captain]

BigPete

 

 

 

There was a good discussion and some pics on the toe-in and negative camber issues and solutions in the " Practical experience with wheel alignment & tow-out" thread in this "Jabiru user's group area".

 

 

 

Regards Geoff

 

 

 

[glenns]

Well pointed out. Next time I will check my work before submitting :-)

 

You are correct it is the camber rather than the toe in that I am talking about.

 

 

[Ross]

Hi All

 

My J160, yet to move out of the garage, presently has to my mind very excessive Positive Camber, the wheels are leaning out at the top without an engine and no wings yet.

 

They obviously ought to be vertical or even possibly a small negative camber with the top of the wheels leaning slightly in when the plane is fully loaded at MTOW.

 

Consider what happens in a maximum cross wind landing and also when the plane is not fully loaded which is the condition the plane will be in most landings..

 

I reckon they should have as close to zero toe in as possible, they obviously have excessive toe in or toe out at the moment as the tyres squeal on the concrete when moved.

 

For more information on these adjustments do a Google search for "tyre toe in" probably mainly applicable to motor cars.

 

I do remember older X-ply tyres on old rear drive cars were toed in somewhere around a 1/16" to 1/8" and the front wheel drive mini minors were toed out 1/16" I think. I think newer rear wheel drive vehicles with radial tyres were often set to zero toe in on their front wheels.

 

If the above figure were any guide they would be roughly halved or less for the smaller tyres in use on the Jabiru J160.

 

I am inclined to go for zero or slightly negative camber and zero toe in in fully loaded configuration but to check if it changes from MTOW to empty tanks and if so to set it at zero at a bit above the middle of the range if possible.

 

 

[Guest brentc]

You probably shouldn't modify your camber until the engine has been fitted and some more weight gets added. Even mine screeches and grinds on the concrete when I move the aircraft 3 years after building it. This happens when it's not sitting flat. After you've taxiied around the tyres will sit flatter on the concrete. Given the size of your wing tanks once you put some fuel in they will sit flatter again and will settle a little after time.

 

 

[Guest brentc]

I took this a couple of weeks ago.

 

This is an example of the camber we are discussion on a factory built J430. When on the ground this one sits pretty flat.

 

 

 

[Yenn]

Do not compare aircraft with cars for toe in. A car uses its front wheels to steer whereas a plane uses the nose wheel which is a single wheel. A cars toe in helps to maintain easy steering both while straight and during a turn.

 

 

[vk3awa]

Unless it's a taildragger Ian!

 

 

[BigPete]

It looks like one of legs were not cleaned up correctly after being removed from the mold and this has caused excessive toe in on the passenger side to add to the problem.

Hey Glenns,

 

I may have a similair problem with one of my legs - there seems to be more camber on one side than the other.

 

Have you checked the airframe for being level?? Spirit level across the bottom of the door openings. I believe.

 

regards

 

 

[glenns]

Hi Pete,

 

Thanks for the tip but I will have to wait until I fix the more immediate problems. See Ultralight crashes at Gawler in the Incidents and Accidents section for more info :-)