Old correspondence

[ben]

Can you tell us any more about this "GT" car John? Any pictures?

With standard gearing 80mph corresponds to approx 4300rpm so 100mph comes up at 5375rpm. (CF valve bounce at 5200 so maybe speedo a bit optimistic?)

Norman, in the wide open spaces of East Anglia, downhill with a following wind etc, would have been doing 112mph at 6000rpm!!!  Now I know what to say when the kids ask  "What will she do Mister?"  The following wind is very important however.
And it would be fascinating to know what pistons he used and what compression ratio. And where do you get valve springs made for £3 per set! And he almost certainly had standard alloy rods. Nerves of steel 'tho.

[simonandjuliet]

Good morning

This letter covers mock crankshafts , BRM wheels and the camshaft that was mentioned previously along with some other subjects.

No need for blanking strips on this one - sorry about the visibilty of names, I couldn't see them on my screen. Thicker paper next time !

I am sure I remember Harry showing me the camshafts on one of his shelves at Heath End, but to be honest it was a bit like being a 6yr old at Hamley's ! I never saw a 4 branch exhaust though and still haven't !

[ColinMarr]

The "GT" Aprilia that John refers to was NGP 50 - see photo below taken by John Maltby. The other photo is a race-prepared Aprilia, probably that of Bob Gale in late 60s/ early 70s. Both of these photos are in the LMC Library collection and should be viewable online.

Colin

[lancialulu]

Can you tell us any more about this "GT" car John? Any pictures?

With standard gearing 80mph corresponds to approx 4300rpm so 100mph comes up at 5375rpm. (CF valve bounce at 5200 so maybe speedo a bit optimistic?)

Norman, in the wide open spaces of East Anglia, downhill with a following wind etc, would have been doing 112mph at 6000rpm!!!  Now I know what to say when the kids ask  "What will she do Mister?"  The following wind is very important however.
And it would be fascinating to know what pistons he used and what compression ratio. And where do you get valve springs made for £3 per set! And he almost certainly had standard alloy rods. Nerves of steel 'tho.

Anyone who knows East Anglia knows there aren't any long hills to speak of - at least I don't know of any, but there are some nice long straight roads esp in the Fens, speed guns permitting....

OVS regularly wound its speedo round to nought but it was horribly optimistic. Calibrated by following car (merc) and GPS it was 25mph over at 70mph. Looked impressive but was useless to drive to  . I have now calibrated by moving the needle back 25mph while holding the shaft at 70mph. It reads quite well from about 50mph but is useless below 25mph  .

OVS has Fulvia pistons but I don't know the compression except I need to run 97 octane and use octane enhancer to avoid pinking (yes timing is spot on). I don't know if the engine has been balanced but according to notes on file the flywheel has been lightened (by how much  ).

I have attached a spread sheet showing predicted mph/1000/gear. This is for a Michelin 165 400 tyre. I would welcome comments. Obviously Norman's lower radius wheels would allow the car to over rev for the same speed.

Tim

[rogerelias]

Re NPG 50, I went in this one xmas when Maltby lent it to my dad, i can still remember the engine note, also where I am sitting writing this, the same picture is on the wall next to me.

[JohnMillham]

Can you tell us any more about this "GT" car John? Any pictures?

With standard gearing 80mph corresponds to approx 4300rpm so 100mph comes up at 5375rpm. (CF valve bounce at 5200 so maybe speedo a bit optimistic?)

Norman, in the wide open spaces of East Anglia, downhill with a following wind etc, would have been doing 112mph at 6000rpm!!!  Now I know what to say when the kids ask  "What will she do Mister?"  The following wind is very important however.
And it would be fascinating to know what pistons he used and what compression ratio. And where do you get valve springs made for £3 per set! And he almost certainly had standard alloy rods. Nerves of steel 'tho.

NGP 50 was a great car. It's the only car I have ever driven with a steering column gear - change and a crash gearbox, but it worked very well. I helped Bob West replace all of the brass bushes in the complicated linkage, removing the slop - and it was a delight to use after that. The knob on the end of the gear lever was a sort of yellow plastic and was either hexagonal or octagonal (I forget which). You could change gear with one finger sometimes. The steering wheel was nearly vertical and the steering very light and positive. The one thing I didn't like, was the hand brake. It was a lever under the dash which had little effect.
 The Norman Wilson letters are very interesting. His quoted time of 77 seconds at Prescott doesn't sound very fast, even though it was on the longer track. These days, Lambdas can get up the hill in under a minute and I wouldn't think it takes 17 seconds to take in the extra loop. Next time I'm at the VSCC library, I'll look up Norman's time at a VSCC event. I remember there was a bit of friction between John Maltby and Norman, but I don't know why.

[DavidLaver]

Having grown up in the Fens I can say that while the hills might not be significant the tail winds certainly are.  "Some say" there's not a single hill to stop an east wind between Ely and the Kremelin.

As for the straights I could imagine Aprilia suspension being a great benefit as with subsidance it gets pretty hairy bouncing along the crown of the road.  You only drift towards the edge when something else is coming the other way and then only at the last possible moment.

In Norfolk, such as through the Thetford Forest, there are some brilliant long smooth straights.  Likewise between Cambridge and Newmarket.  

Am struggling to think of good long hills up that way...

David

[DavidLaver]

Prescot times - see column 4 of the Pre War Austin 7 Club "Bert Hadley" championship results for some times including the loop:

http://www.pwa7c.co.uk/hadleylastyear.htm

My instinct is ten to a dozen seconds slower than VSCC times.  The challange now is to find one of those cars that was also at VSCC Prescot.

David

[chugga boom]

does the gt still exist??

[rogerelias]

I believe its gone back to Italy, but where or who I don't know

[simonandjuliet]

Or maybe this one should be under Aprilia technical - converting to thin-wall bearings

I am sure this will have been seen before in one format or another, but I remember doing the conversion on YRV 700 (and I think PGY has been done as well - must remember to ask Paul !)
As I recall,  when we did the mod we filed small grooves in the back of the shells so they didn't foul the bolts

Only a couple more letters after this !

[JohnMillham]

Is it possible to get a better scan? The last one is almost impossible to read, as it's so lacking in contrast. I'm sure it will be very interesting, so I'd quite like to read it.
Regards, John

[simonandjuliet]

Re-scanned - can't make any clearer due to file size

[ColinMarr]

It was legible on my screen, but I have scanned it again as a JPG and beefed up the contrast a bit - see attached.

I find all of this fascinating - keep it up!

Colin

[JohnMillham]

Thanks Colin. Slightly better, but still a struggle to read it. (I got the gist of it.) Very interesting!
 Regards, John