Bigger wheels for J120

[Ian Sugden]

Can anybody advise the process to legally change the factory wheels on a Jab J120 to larger ones? It seems like a good idea if you are operating in/out of grass/dirt strips which, with the small wheels fitted, can make you feel like you've fallen down a mineshaft instead of just the space between the tufts of grass.

 

Does anyone know of an engineer in Nthn NSW that can legally do the job?

 

Thanks all.

 

Ian:gerg:

 

 

[Mick]

Hi Ian,

 

I am pretty sure that your J120 will be registered as an LSA.

 

As such Jabiru are the only one's who can approve a change.

 

One of the traps about the LSA regulations is that only the manufacturer can approve changes to the aircraft. A CAR 35 engineer can approve changes to a 747 or A380 but not to an LSA!!!!!

 

Cheers

 

Mick

 

 

[HEON]

Give Lone Eagle Flying School at Clifton (Trevor Bange) 0429378370 (07 46958541) a call as I think they went through the correct procedure to do this on a 160.

 

Probably inform on correct method.

 

 

[Ballpoint 246niner]

I spoke to Stiffy about this when I orderd mine- LSA means NO.

 

The 120 was designed as a production filler a/c to keep the production teams busy in between other orders, hence the no frills approach to the model, some of this has been relaxed as demand came off through the GFC but bigger wheels means redesign and they ain't doing this for the 120! If you fit bigger wheels yourself it'll revert to non LSA (or special LSA -SLSA or experimental if VH)and even then the legs and axles won't be rated for it. They may allow fitment of the new legs,which might improve bump absorbsion but talk to Jamie/Doug at Jabiru first. Given the focus on undercarriage bolt life as per service bulletins you can see this will spiral into a safety/non compliance issue pretty quickly.

 

Been through all this so just trying to give you the heads up...

 

 

[Relfy]

When I picked my 120 up a few weeks ago, one of the staff their even commented on my check flight that the smaller wheels vibrate and reverberate on the runways with small cuts/lines in them. Surely putting slightly bigger wheels on wouldn't be such a huge problem as far as certification goes and would actually improve safety to a certain extent? My thoughts.

 

 

[kevinfrost]

I fitted the (Fergy) tractor try ribbed tyres to our 120 after numerous puntures and excessive tread wear on our sharp metal strip.

 

They fit staight on with slight adjustment to the fairing as the tyres are 30 mm larger in diameter. Fixed the puncture and wear problems very cheaply. Handles the rough surfaces much better. I got the idea after talking to a unnamed flying club who use dirt and sealed strips and were tired of repairing tyres. At the time of conversation they had been using them for around 12 months and were very happy with them. That was good enough for me so I ordered 2 sets, best money I've spent, with the added safty if the tyre goes down the discs don't get damaged and less chance of A/C and or bodily damage. Can't help with the front tyre, we put a gattor in ours, no more puntures. Might not be legal but but works for me.

 

 

[kevinfrost]

That is tri ribbed, not try.

 

 

[Mick]

I don't understand how J120 can be an LSA - surely, a factory built J120 is 95.55 para 1.6 not para 1.8 ???

It's all in the certification process. To be standard RAAus you need a type certificate. For LSA the manufacturer only has to certify that the aircraft meets the ASTM's that apply to LSA, a much cheaper process.

 

 

[Mick]

Might not be legal but but works for me.

Hope you have lots of $$$ should you ever have an accident because you are now unregistered and uninsured.

 

 

[BigPete]

Yes, they have, as well as the J160 that's why is now a J160D and not a J160C.

 

(Now a collector's item. I have one, please que from the left....)

 

This means that any changes/improvements that Jabiru do, won't cost them a zillion dollars for certification.

 

regards

 

 

[Steve Donald]

Bigger wheels

 

Hope you have lots of $$$ should you ever have an accident because you are now unregistered and uninsured.

NO ISSUE HERE, the factory supplied tyre is like a rag, they blow on coarse bitumen and most owners will know puncture all the time, you learn landing with a flat real quick, yep change them, Kevin used the fergie type i used 8 ply aircraft tyres from the aero shop in the Mag, same rim size no change to the wheels nothing aircraft grade and stamped, excepted as a high performance aero Tyre, even when you let the air out they hold form ie the wheel pant is off the deck and the plane still is controllable..... the factory Tyre when flat will not roll also the brake disk is on the ground it is not round and it is it that you roll on and it is designed like a 50 cent coin believe me a real handfull to land when flat it happened to me at St George i had to get the mobile heli pad out to the runway taxi was out of the question, stock tyres are bloody dangerous and disbelieved them being approved. **** em off any CAR3 will agree.

 

 

[Ian Sugden]

Guys,thanks to you all for the most helpful hints here and sorry for my tardy response.

 

I will have a crack at going through the channels - I want it legal, but somewhere there must be an approval method. Afterall, years ago I can remember a written off Piper Pawnee being converted to a two seater legally - cost a bomb though I'll bet. If, as you say Mick, A CAR 35 engineer can approve a change to a 747 then this would be a stroll in the park. It must just be the powers that be find it a bit tricky and thus the decree is that nobody is capable to perform this most difficult task on this unbelievably heavy 2 seater!!

 

As I understand it now, Jabiru must give permission for the mod but it can be signed off by a qualified engineer - this negates the liability issue that Jabiru could have whilst still keeping it legal. I will continue and advise the end result, but probably not until 2011. In the meantime if anyone has more advice I'm all ears.

 

Cheers all and thanks again.

 

Ian

 

 

[Steve Donald]

Guys,thanks to you all for the most helpful hints here and sorry for my tardy response. I will have a crack at going through the channels - I want it legal, but somewhere there must be an approval method. Afterall, years ago I can remember a written off Piper Pawnee being converted to a two seater legally - cost a bomb though I'll bet. If, as you say Mick, A CAR 35 engineer can approve a change to a 747 then this would be a stroll in the park. It must just be the powers that be find it a bit tricky and thus the decree is that nobody is capable to perform this most difficult task on this unbelievably heavy 2 seater!!

As I understand it now, Jabiru must give permission for the mod but it can be signed off by a qualified engineer - this negates the liability issue that Jabiru could have whilst still keeping it legal. I will continue and advise the end result, but probably not until 2011. In the meantime if anyone has more advice I'm all ears.

 

Cheers all and thanks again.

 

Ian

Hi Ian, the tyres from ******* 8 ply are aircraft grade 8 ply and dont change anything, the standard tyre is as soft as a rag and when it blows will leave you on the brake disk which is not round believe me a real handfull to keep on the runway, a phone call to Jab would surely accept this as the stock item is a safety concern the replacement tyre will hold section and keep the disk off the ground and roll still the stock one will not you will have a wheel pant on the ground as well as roll on the disk, there is no substance to the tyre, it is not aircraft grade a flying school at bundy is using these tyres as well for the same reason, that is where i found out about them, as for regs and safety, like see and avoid so is any other obvious safety concern with the stock tyre you stand a very good chance of losing control on landing with a flat or blow out, i would not wait any insurance company would agree and so would most 120 operators perhaps a joint request of approval, the tyres that Kevin sugested are great as well and i must reinterate no changes are made to wheels or fittings its just a heavier tyre.

 

 

[jacmiles]

Hi Ian, the tyres from ******* 8 ply are aircraft grade 8 ply and dont change anything, the standard tyre is as soft as a rag and when it blows will leave you on the brake disk which is not round believe me a real handfull to keep on the runway, a phone call to Jab would surely accept this as the stock item is a safety concern the replacement tyre will hold section and keep the disk off the ground and roll still the stock one will not you will have a wheel pant on the ground as well as roll on the disk, there is no substance to the tyre, it is not aircraft grade a flying school at bundy is using these tyres as well for the same reason, that is where i found out about them, as for regs and safety, like see and avoid so is any other obvious safety concern with the stock tyre you stand a very good chance of losing control on landing with a flat or blow out, i would not wait any insurance company would agree and so would most 120 operators perhaps a joint request of approval, the tyres that Kevin sugested are great as well and i must reinterate no changes are made to wheels or fittings its just a heavier tyre.

I agree with Steve, The tyres the 120 comes out with from the factory are unsuitable to the point of dangerous! Jabiru should address this issue before someone gets hurt.

 

 

[Ian Sugden]

Thanks Steve & Jac. I've sent off a couple of e-mails this morning to kick start the chain of events, I'll keep you posted.

 

 

[Ian Sugden]

It would seem to me that there is a bit of concern about the safety of the tyres on the J120 out there in aeroplane land. Has anyone made these thoughts/concerns known to the relevant safety people or the factory? Steve, would your experience out at St George would be worth recounting for the benefit of all?

 

A low hour/inexperienced pilot (I'm very inexperienced in landing with a flat tyre) could end up the wrong way trying to roll on a hexagonal brake disc with its assymetric properties. All a bit worrisome on the original quality front from these posts.

 

I've just received an e-mail back from an authority that says "About the tyres, I have no problems reported concerning J120 wheels and or tyres."

 

Any further comments from J120 owners out there?

 

 

[Ian Sugden]

Hi BlackRod, seems we both have the same idea - difference being I don't have any experience on the J120.

 

As an extra the J120 is certified as a S-LSA and the following was received just a short while ago "Sorry but S-LSA are different from everything else. In that any mod NOT APPROVED BY THE MANUFACTURER is not permitted. Having said this the owner of the aircraft can modify it legally, but there is a catch, the aircraft will have to be reassessed for a new EXPERIMENTAL LSA Certificate of Airworthiness, which means that you the owner then become 100% responsible for the safety and airworthiness of the aircraft and it cannot be used in a flying school." I have requested a clarification of "NOT APPROVED BY THE MANUFACTURER ", wether it means permission, approval of work done by an engineer or work done by factory. Will advise further. Cheers

 

 

[Bruce Tuncks]

To be significant, wouldn't any modification have to be relevant to a mishap leading to a claim?

 

For example, if you had changed the tyres but your claim was due to collecting something with a wing tip due to error of judgement on taxying, surely the insurance company couldn't deny your claim?

 

If they could, I reckon they would be out at every accident site looking for the slightest thing and denying claims because a placard had been moved a bit.

 

I'd really like to hear stories of denied claims, they sure would teach us some important stuff.

 

cheers, Bruce

 

 

[Tomo]

I agree with Steve, The tyres the 120 comes out with from the factory are unsuitable to the point of dangerous! Jabiru should address this issue before someone gets hurt.

Just curious... how's that?

 

They wear relatively quick if operating off bitumen all the time, but if they are worn past their safety point. It isn't the tires fault, but the drivers, isn't it??

 

Daily inspections = tire condition... (wheel spat or not, I never go anywhere if I can't see what the tread/tire is like)

 

If it's way to rough for it, it also isn't the manufacturers problem, isn't it...?

 

Sorry If I'm sounding annoyed, but I don't like seeing people getting knocked for something that isn't their problem. Just like you don't go complaining to Kia because they didn't make their Carnival suitable enough to handle driving on the beach.

 

Sorry.

 

Btw, I've done a lot of my flying in a J120.

 

 

[Ballpoint 246niner]

Just curious... how's that?They wear relatively quick if operating off bitumen all the time, but if they are worn past their safety point. It isn't the tires fault, but the drivers, isn't it??

 

Daily inspections = tire condition... (wheel spat or not, I never go anywhere if I can't see what the tread/tire is like)

 

If it's way to rough for it, it also isn't the manufacturers problem, isn't it...?

 

Sorry If I'm sounding annoyed, but I don't like seeing people getting knocked for something that isn't their problem. Just like you don't go complaining to Kia because they didn't make their Carnival suitable enough to handle driving on the beach.

 

Sorry.

 

Btw, I've done a lot of my flying in a J120.

I'm with you Tomo- 105hrs, bitumen and grass no flats, no problems, 20 airstrips from Temora to Bundy and lots in between. Buy a cub with alaskan wheels then complain about the drag and bouncing like a trapoline - try complaining then- everyone would laugh!

 

 

[jacmiles]

Just curious... how's that?They wear relatively quick if operating off bitumen all the time, but if they are worn past their safety point. It isn't the tires fault, but the drivers, isn't it??

 

Daily inspections = tire condition... (wheel spat or not, I never go anywhere if I can't see what the tread/tire is like)

 

If it's way to rough for it, it also isn't the manufacturers problem, isn't it...?

 

Sorry If I'm sounding annoyed, but I don't like seeing people getting knocked for something that isn't their problem. Just like you don't go complaining to Kia because they didn't make their Carnival suitable enough to handle driving on the beach.

 

Sorry.

 

Btw, I've done a lot of my flying in a J120.

Im sorry, im just a beginner who doesnt know what he's talking about, Ill order another set of chen chings off Jab straight away.I'd get some for my mower too seeing how cheap they are but you know what, i wouldnt trust them on my mower.

 

 

[Steve Donald]

Just curious... how's that?They wear relatively quick if operating off bitumen all the time, but if they are worn past their safety point. It isn't the tires fault, but the drivers, isn't it??

 

Daily inspections = tire condition... (wheel spat or not, I never go anywhere if I can't see what the tread/tire is like)

 

If it's way to rough for it, it also isn't the manufacturers problem, isn't it...?

 

Sorry If I'm sounding annoyed, but I don't like seeing people getting knocked for something that isn't their problem. Just like you don't go complaining to Kia because they didn't make their Carnival suitable enough to handle driving on the beach.

 

Sorry.

 

Btw, I've done a lot of my flying in a J120.

It is not about rough surface the slightest *****le thorne sharpie will have you landing with a flat tire, on those 120 tires and these were new tires i flew with 2 spare new ones in the back, quite a few pilots who have flown their new 120 home from Bundy have had a flat on the way home , as i said they have no structure a new tyre for the 120 can be screwed up like a rag in one hand, this is not about how good a 120 is flown the fact is if the tyre is flat you are on the disk with a stock tire, add a cross wind to that good night dick had to edit the tire that failed on me was new and there is not enough thickness for wear marks like i said a school at bundy used em for that reason, hec nice to have a reasonable chance of not having a flat when you land, i had 5 punctures on stock tires 0 on the new ones plus i could do circuits on flat tires now if i wanted to, Nose wheel is not an issue no weight and is never on the ground much still steers flat, but it has 2 tubes in it since it went flat heaps of jacks out bush.

 

 

[Tomo]

Thanks Steve, an informative post.

 

Have you ever tried that TrueBlue Goo stuff? It's aviation approved I believe. And doesn't cause unbalance on touch down, well so I've heard.

 

Might save some angst, and still keep your aircraft certified.

 

Just a thought.

 

 

[Relfy]

I'm keen to know also Tomo if any 'goo' type compound works as well. Is anyon using a product like this and can they share their experiences?

 

 

[Ballpoint 246niner]

Just on a simialiar note- Jabiru are now advertising the 120 with electric flaps! must be school pressure- I like the manual setup.

 

On tyres - Green slime works well in the trikes we've run but you need to be liberal with it, and only good for pin holes.