Tyres Creeping on Wheel Rims
 

Aircraft tyres creeping on the rims.
Does this ever happen?
An F-16 pilot recently remarked that he was limited to applying full max dry power on the brakes before take off with a light aircraft as there was a risk of the tyres creeping on the wheel rims. This necessitates applying progressive AB/reheat on the roll.
Cannot believe this as there would then be a risk of tyre failure when using max braking on the move.
Perhaps he was confused with the inability of braked wheels to hold without skidding against the high thrust of current engines.
What limitations apply to which high performance aircraft to prevent tyres skidding during brake hold before take off?
Has anyone experienced tyre creep on wheel rims and if so under what circumstances?

More likely that the a/c would skid rather than cause tyre creep on the rims.

If tyre creep was going to be a problem I believe landings would be more likely to cause it than setting full thrust on the brakes.

Regards,
BH.

Believe the Phantom was the same

All aircraft tyres will creep, even the slow ones like a Tiger Moth. They creep on initial spin-up on touch-down. If the tyres have inner-tubes then a 'creep mark' will be painted on the wheel and tyre so that the creep can be monitored. Generally the creep mark is about one inch in legnth along the wheel rim, if the tyre creeps by half this amount then the tyre will be deflated and the wheel re-set. If this is not done the wheel can sheer off the inflation valve.
Larger aircraft generally have tubeless tyres and they can creep as much as they like, so they don't have creep marks since there is no danger of the valve being sheered off.
I have never known a wheel to creep by applying full power with the brakes on. When the tyre is under a dynamic load it will grip the wheel more tightly due to its fit on the rim. It is more likely to creep under staic conditions when the tyre is 'at rest' so to speak. It is in this condition when it hits the runway and thus is more prone to creep.

Interesting thread - I recently replaced a tube on a light twin and didn't notice any 'creep marks' but will have another look. I would have thought that at 40psi there would not be any creep to speak of, perhaps with minimal inflation one might expect it (I well recall tyre clamps to prevent it on some of my early motorbikes!).

Also have seen a number of flat-spotted tyres where people have landed with brakes on (ouch!) or run off the end of the runway, certainly no ripped valves in any of these cases so if the tyres did creep then all that baby powder did its job!

There can be some creep on first landing after a tyre change too. In addition, you should check the tyre pressures after the first landing as there can be a loss. This appears to be just a bedding in problem and second flights are usually ok.

FYI I recalled that I had marked the valve position on the tyre I recently changed, so that would indicate if there was any tyre creep...

I've just been down to check it and, after a dozen landings or so, there has been no creep. If I remember, and the mark stays there, I'll check it again in a few weeks :)

I have heard of this problem, but been cautioned about it being a problem if brakes are applied after take-off on aircraft with large, high-profile tyres. On touchdown you have the runway surface applying a change in angular momentum to the tyre (at the outside of the diameter) and the tyre bead transmitting a lesser change in angular momentum to the rim. If you apply the brakes after take-off, the opposite applies; you have a rapid change in angular momentum of the braked rim, and an even larger change in angular momentum of the high profile tyre being absorbed by the bead. Thus, we did not apply brakes before retracting gear after take-off.

The tyres had creep marks. I never saw anything written in the manuals about it.

I accept that where landing gear retracts across the lateral axis, the gyroscopic effect may be worse that the tyre creep issue. But then I've never seen an aircraft with large, high profile (high flotation) tyres that are retracted laterally. All pure speculation on my part in the absence of published warnings/cautions.

Back in a previous life it was standard procedure after take off to apply the brakes before the landging gear was retracted, the aircraft a Macchi MB326 jet trainer.
On the Boeings I have flown the brakes are automatically applied when the gear is retracted and if you have a brake capped due to a malfunction then there is a time limit after takeoff before the gear can be retracted.
Main gear liftoff speed, in a max weight aeroplane, is around 170kts/310kph so the gyroscopic effect would be considerable if the wheels were not braked.
Regards,
BH

The main wheels of the deHavilland Canada DHC-5 Buffalo had rather small diameter rims relative to the large, high floatation tires. As I recall, to prevent tire creep, teeth were moulded into the tire bead, and wheel rim so as to interlock upon assembly of the rims. I rode trough a number of very STOL landings and takeoffs, and was never aware of tire creep. I guess it worked!

Pilot DAR

Milt,
I have heard of tyre creep due to high power with brakes applied relating to Grumman SNJ6 type especially during carrier operations on HMAS Melbourne.

Milt,
In previous life, commanded the F-16 Combined Test Force. Your F-16 friend was correct, Max AB is not allowed due to tire rotation on the stationary wheel when the brakes are set. At brake release, max AB is available immediately, all the way up to segment 5, as far as the wheels are concerned. The progression to segment 5 AB is a function of engine stall margin, not wheel/tire limits from that point on.
Cheers,
Stump

stump2

As an experimental TP I can hardly believe that tyre creep on an F-16's wheel rims could be assessed as acceptable.
Obvious follow on restrictions would need to be applied to max braking approaching skidding when one could expect the forces to cause tyre creep to be at a maximum.
An efficient anti skid system could hardly be trusted so close to the max braking envelope.
Also a touch of the brakes after lift off could be a hazard.

Did you know Jim Rider?

Milt

Sorry to be thick but I don't see why you are bothered by tyre creep (however caused) if there is no tube

JF

If the aircraft actually starts to move forward before the pilot remembers to release the brakes, the tyres and rims will get very hot, very quickly, won't they?

ZeBedie

JF raises a good point but being tubeless then very soon after the tyre moves on the rim I reckon that the high pressure nitrogen will find ways to escape. Potential results - either a failure during the take off roll or a flat on landing.

Once did a max braking test in a heavy Valiant imparting design limiting energy to the brake units. Something like 140 million ft pnds. Two tyre failures and brake fires towards the end of the roll out. The stripped brake units looked terrible after being doused in dry powder extinguishent. The tyre carcasses seemed to be intact with failures apparently occurring at the rims or perhaps the wheel blow out plugs let go. Cannot recall the detail in the test results.

I remember reading a biography where the author mentioned that his SOP (on something large) was no braking after takeoff for this very reason, and in another book, where the author mentioned that it was the opposite (on something small) because the wheel wells were so snug that the extra diameter of the spinning tyre caused chafing.

Then I looked at my car and saw red dots which I thought must be creep marks, but the logical place would be next to the valve. I finally figured out they were marking the heaviest point so they could be mounted opposite the valve. (Why don't they mark the lightest point?)

Aaaaaaaaaa

The early Victors had a park brake lever covering the gear up button. One had to twist the park brake lever to park before retraction to ensure that the wheels would retract when not rotating. The designers had not allowed for the extra diameter of the spinning tyres or for out of balance movement.

Of course this led to the inevitable. A TP was flying a few circuits and changed his mind about gear retraction after a touch and go but after the park brake had been applied. The resultant landing spoiled his day and a multitude of tyres.

Does anyone remember how that problem was solved?

An underinflated tyre on a large jet is almost impossible to detect by eye and it is likely to creep so the marks might give you an early warning of a soft tyre.

Wheel braking during retraction serves a couple of functions. Firstly it stops any vibration as the gear goes into the well as this tends to scare the punters.

Most importantly if a tyre has failed on the takeoff roll it might well have long strips of tyre carcase spinning at high speed going into a wheel well lined with hydraulic reservoirs, valves, pipelines.

As a back up the Boeing 737 NG has small shear off fittings protruding below the wheel wells. If a spinning carcase hits one, it shears off dumping the hydraulic fluid from the gear retract line, the retract sequence stops keeping the damaged wheel out of the bay.

On the 737 there are no wheel doors and the wheels push up through rubberised blade seals. A spinning wheel would damage the seals as well as scaring the punters.

I believe that if you advance the throttles on a 737 with the parking brake set you trigger an audible configuration warning.

I was always taught that a pilot should not jump on the brakes after takeoff, becasue the rapidly spinning tire, which had increased diameter a bit due to centrafugal force, would be a bit more loose on the bead, and could turn on a suddenly stopped rim. I take the side that even a tubeless tire should not be sliding on the rim. Something's going to get damaged, and it will be less safe.

I've seen lots of tube tires (both aircraft and otherwise) where the tire (or at least tube) has turned on the rim, and the valve stem is projecting at an odd angle.

Of course, my comment is withdrawn, if the aircraft manufacturer specifies this procedure.

Pilot DAR