Spitfire Wheels

[Denford]

Could somebody please explain the rational behind the number of 'spokes' on a Spitfire wheel.  Initially at 5, final models had 3.  Some mid-series eg PRXl could have either 5 or 4.  Could they, in emergency, have been 'mixed' ie 4 spoke one side and 5 the other?  Some had the spokes blanked off: to what purpose?

 

And the tyre treads?  In model accessories there's quite a good selection of different treads, square, diamond, circumferential and none.  Usually in deep shade, almost all aircraft it seems had no tread at all.  What were the special circumstances that did require a tread: snow, mud, sand, carrier deck ?  That if a choice was available at the location.  Burma it seems would have been a real problem: mud half the year and dust the other!

[Graham Boak]

The fewer the spokes the stronger the wheel.  As the Spitfire got heavier stronger wheels were needed.

 

I don't see tread needed for mud, as they would only clog up anyway.  Remember that Spitrires were designed in the days of grass strips, so I suspect that treads came in when hard runways became more common.

[greatgonzo]

The thread was of no importance on grass fields. The characteristic geometry of the undercarriage did the job: \  / looking from the front and 'toe in' looking from above:  /  \ (nose of the plane to the top of the screen). Moving to Europe and using hard runways  meant disaster for tires. it was necessary to correct the geometry  and straighten the wheels.  And threaded tires became wanted obviously. The geometry correction was not done  until the end of war, though.  The modification took time as usually.

 

So Graham is right, as You can see. Even if possible, I don't believe there was a Spitfire with different wheels on both legs. The wheels differed in construction but also in dimensions, sometimes having the same number of spokes and looking similar. Different tires wouldn't look very strange unless threaded tyre and slick would have been used. It was quite a common practice for example with USAAF fighters on any theater.

[viscount806x]

Just looking at one of my Eduard 'combo' kits, I can see that wheels for the IXC and IXE are very different both in spokage and diameter. I think that there probably isn't a straight forward rule of thumb which can be applied, but I'm not a Spit expert and tthem what are might disagree.   Hopefully!

[Graham Boak]

I'd be very careful with those Eduard parts.   Remember that there were three main different variants here - the original F Mk.IX, the LF Mk.IX and the LF Mk.IXE.  (Not counting the HF Mk.IXs as being a simple engine change.)  As some of the Mk.IXE airframes were just modified Mk.IXs with the c armament, a different wheel and tyre would be peculiar.  I strongly suspect that the larger wheel and tyre is more likely to be linked to the post-war modifications for hard surfaces, with the added bulge on the upper wing, and thus seen on late Spitfires IXs regardless of the sub-variant.  Plus of course Mk.XVIs.

 

I must admit being left wondering how a larger diameter tyre fitted into the wheel well, but no doubt someone will be along to explain.

[Troy Smith]

16 minutes ago, viscount806x said:

I can see that wheels for the IXC and IXE are very different both in spokage and diameter.

 

2 minutes ago, Graham Boak said:

I must admit being left wondering how a larger diameter tyre fitted into the wheel well, but no doubt someone will be along to explain.

 

IIRC the 3 spoke hubs are a larger diameter with then tyres with the same outside diameter, but larger inner diameter, 

as seen on the Eduard XVI sprue

the  4 and 5 spoke and the covered hubs are smaller

 

As stated, the less spoke will take a greater weight,  so you see the 5 spoke on the earlier Spitfires,  Mk.I, II. V. early IX,  and the 4 spoke was first seen on the Mk.VIII IIRC.

the spoke become the standard later fitting,  and as said, the 3 spoke is a post war fitting, and AFAIK, the different wheel angle was the reason for the wing bulge.

@gingerbob  maybe able to add more

20 hours ago, Denford said:

Some had the spokes blanked off: to what purpose?

these are plain covers,  covering a spoked hub beneath, and I believe they were to stop dirt getting in.

 

Hopefully my basic answer will winkle out a more precise one