Museum Static aircraft tyres

Filling of static aircraft tyres

When we dismantled the Percival Prince at Caernarvon a few months back it was found the main wheel tyres were full of concrete!
It proved to be sturdy enough for the job but in all other respects was a dead loss.
It took three of us to lift a single wheel. There was a “window” cut into the tyre which had been made to pour in the concrete. The corrosion of the hubs rendered them barely re-usable and last but not least; I was witness to one of the lads taking hours to separate the remains of the tyre from the hub – almost impossible due to the corrosion and access for getting a mini-brinder in. I think he managed eventually. Verdict – Concrete: Cheap but not good.
Axle stands and low pressures are the best solution but even then, if the aircraft has to be moved some time in the future the tyres would need to be re-inflated, not necessarily to service pressures but to a considerable degree if it’s a heavy a/c and this could be dangerous. I’d suggest lifting the axle stands onto dollies and towing it that way if there’s any doubt at all.
On the safety side, if inflating a tyre to a high pressure and you are worried about the integrity of the rubber, stand to the front or rear of it. Tyres invariably blow out via their side walls not their treads, which are considerably thicker and stronger, so if it does go off, apart from a little temporary deafness(!) you should be OK.

Right I’ll say it – I dont like tyre filling….

It appears to me to be a short term solution for a long term problem. It renders the tyre unremoveable, and hence if corrosion problems occur within the wheel in future, it makes it impossible to conserve without destroying the tyre (leading to another problem).

I’m not saying I know the solution, but I think axle stands and U/V reflective wheel covers (unsightly, but they may help stop the degradation) are a better short term solution, though it is not one I currently use myself!

I would invite anyone involved in the process to dismantle a typical wheel assembly from an average aircraft, and play ‘Spot the corrosion product’ once it is apart….

Bruce

Interesting (useful) discussion!

The RAAF Museum’s aircraft have recently had dedicated discrete axle stands made (by the Friends in the RAAFM workshops) for each aircraft displayed inside. Due to the weather factors, external aircraft don’t have them. Upto Boston and F-4 Phantom in size/weight.

Obviously the unloaded tyres can have little (or no) pressure, slowing aging effects or risk of breakup, as well as no chance of a bang. Moving the aircraft can (I guess) be a problem, if a rare tyre type won’t re-inflate to move the machine…

When examining the RAF Museum’s Defiant in about 1988, it had a collar around the oleo (painted silver) to keep the oleo extended to ground loading length, and was on axle stands. The tyre was without pressure, but looked pressurised; the assistant with us punched it gently, his fist going into the hub – a most odd effect!

Keithmac’s excellent post is most illuminationg; I’d just add that some of the latter remarks aren’t appropriate for 100+ year conservation plans – but what time-scale is the museum aiming for? The RAAF Museum’s 1945 period G suits are already a conservation and challange to move, because of 1945 rubber quality.

(These are personal observations, and do not reflect museum policy or views. Objects in the mirror may be heffalumps, and this e-mail must be eaten if not addressed to you. etc.)

Regards,

Whilst this thread seems to have concentrated on aircarft kept outside, I’ve had a conversation recently with a museum curator about the effect of the museum’s underfloor heating on aircarft tyres. Looks like I’m into manufacturing more axle stands. thank the lord that the museum doesn’t have any large aircraft…… well not complete ones.

The mentions of degradation due to UV light (this can apply indoors as well as outdoors) reminds me of the suggestion I was told many years ago that “blacking” the tyres with appropriate paint helped shield the rubber from light and thus delayed degradation.

Roger Smith.

Might have been better stated as UV and other factors; wide temperature variations; freezing of the rubber; degradation due to oil or solvent contact etc.

Black paint may help I don’t profess to fully understand the chemical reactions involved – I just know that the preparation of all types of rubber compounds is a very precise and complex process, involving important chemical reactions that smell awful!

Lindy’s Lad

Yes it can be costly, but tyre-filling can also be more cost-effective than designing the axles stands needed to support something like a Vulcan!

I concur with all that has been said so far. We have an ongoing project of getting out aircraft tyres filled with a high density foam, but as a short term solution the tyres are painted with ‘Tyre Black’ and rotated as often as possible. So far we have completed the lightning tyres (removed and foamed), with the Vulcan’s on the hitlist next. Its an expensive exercise though…..

The mentions of degradation due to UV light (this can apply indoors as well as outdoors) reminds me of the suggestion I was told many years ago that “blacking” the tyres with appropriate paint helped shield the rubber from light and thus delayed degradation.

Roger Smith.

Gentlemen,I thank you for the very interesting response.

Don’t intend to get into major debate on the topic but having made a call to someone at Newark this morning I would add the following:

Newark’s original decision re-high pressure tyres was coloured by former Restoration Co-ordinators experience on Vulcans where he saw tyres “go-off” – hence it was assessed to be a potential Health & safety issue and action was taken.

Flat spots can be an issue – understand Newark had an issue with Sea Vixen; partial cure issues with one batch of material.

The system is also beneficial through tubing and filling, where the carcass has degraded beyond normal repair and replacements are not available. Supply and technical support of old-UK based rubber products including tyres, brake-bags etc is becoming an issue.

The company Newark has used is Vacu-Lug and one of their sectors is the mining industry; filling vehicle tyres that are used underground and have to comply with Mine Safety Regulations.

As far as tyre carcasses and degradation goes – I have some experience in the supply of equipment to the rubber compounding industries [nationally and internationally]; as such I understand some of the chemistry involved. My instinct for tyres that are on aircraft outside and subject to high-levels of UV would be to fill them – better safe than sorry!

When I had charge of museum aircraft the RAF regulations for aircraft actually standing on wheels was to inflate to the correct pressure with Nitrogen. Aircraft where possible were to be jacked and the wheel rotated 90Deg every 6 months. If this could not be accomplished then as far as possible aircraft were to have axle stands manufactured, and the aircraft was to be supported on these, with tyre pressures sufficient to give the appearance of full inflation. For many of our aircraft we had a spare sets of movement wheels which were kept for when the aircraft was to be moved.

You have to remember that aircraft tyres are manufactured to withstand forces far in excess of anything the aircraft has to contend with sitting in a museum, and although they deteriorate with age, I never had a tyre blow on me. The surface cracking you often see on old tyres would render then totally unacceptable for flight use, but the underlying re-enforcement is sufficient to keep the tyre together under static and towing conditions provided that acceptable minimum turn radius limits are observed.

Keithmac

Many thanks for the reply’s My concern was flat-spots which causes sidewall cracking and also long term U.V damage. The BAC Lightning tyres are filled with Nitrogen ?

I see from that link to BAPC that Stopping The Rot 1994 had:
“Aircraft Wheels and Tyres – C Chippington”

Roger Smith.

Thanks Roger!;)

I have posted before on this potentially controversial topic – but I understand that all of Newark’s high pressure tyres [Vulcan, Lightning, Sea Vixen etc] are filled; done by a company in Grantham I believe.

As far as BAPC goes check ….

http://www.bapc.org.uk/html/stopping_the_rot.html

See supplemental Papers [1997-2003]; not sure how easy to get a copy!

You could also contact Newark via their website www.newarkairmuseum.org

Also see post #77 on the thread below.

http://forum.keypublishing.co.uk/showthread.php?t=59233&page=3

I remember reading in a thread on here a while ago that some museums fill their tyres with sand and some had tried water?

curlyboy

That would seem the most logical solution. I have had a B25 nosewheel blow on me. Fortunately there was no-one in the vicinity.

I believe the BAPC included tyre care/maintenance in their “Stopping The Rot” series of seminars (next one this October?). I remember Chris Chippington at Duxford did quite a bit of research into foam filling of tyres.
If I am right the BAPC information should be available on paper.
Twin Otter???

Roger Smith.