Steam speed records including City of Truro and Mallard

Most definitely. The Typhoon was designed as a medium to high altitude interceptor, to replace the Hurricane (which also had thick wings). These wings increased drag and limited speed, climb rate and performance above 20,000 feet. It ended up being used mainly as a ground attack aircraft, a role in which it was very successful, particularly in Normandy. It's difficult to understand why Hawker didn't learn these lessons from the Hurricane.

 

Is there reasonably authentic high speed running on levell from GWR?
With a boiler more or less as a Hall and mass/length of whole train known, I can test my cheap power / speed model.
I have the BR test of Halls.

 

Thin wings cost and weigh more and nobody in world had data for profiles at very high Mach numbers in 1935.
Almost vertical dives high,high up was not a design criteria first year of WW2.

 

I feel there’s a need to separate out the understanding of aircraft and trains.

One of the reasons why the NPL tests are significant is that they still form the basis of our understanding of aerodynamics for rail based vehicles today.

Whatever else NPL may have got wrong elsewhere, is ultimately not as relevant to our discussion as recognising they were the first in the world to be developing truly streamlined locomotives and entire trains. Frederick Johansens work in particular gives us a lot of the groundwork that was then refined to the present day.

It is no coincidence that Gresleys A4 Pacifics and the Coronation train so closely resemble some of the high speed trains of today: much of the development and theory remains the same.

The modelling and wind tunnel aspects are flawed, for sure, but they pointed to real world results.

Nobody is, I hope, declaring that they exactly match the conditions and environment of the full size trains, but as a form of modelling, many of the principles were right first time (for example, cross sectional area, smoothing the sides, recognising the issues of drag and how different vehicle profiles interact with each other).

One of the things I am trying to put together for the PhD is the potential to “re run” the wind tunnel trials and learn more about the tests by practical methods. Indeed, we might even be able to add a few more shapes into the equation (watch this space).

 

That might be but trying telling that to a pilot whose plane's speed and altitude are limited by such, against an opponent who doesn't have this disadvantage! High Mach numbers were irrelevant.

 

I think if we get into military aircraft design then things get an order of magnitude more complicated, and the numbers of factors to be considered greatly multiplied. Best left to aircraft forums perhaps?

 

Tregenna Castle June 1932 and Drsyllwyn Castle 1958 are widely cited as two record runs. Presumably there must be logs of those.

 

No
1 to 40 solid wood models used to evaluate/ predict train streamlining in air tunnels by highly paid experts in thirties was just as worthwhile as their advices for profiles for fast aircrafts.
The cost/benefit of research about even.

 

I have found the Tregenna thing and look for Drsyllwyn. Wich of these has boiler and blastpipe most like the Hall tested?

 

I think for the purposes of this thread, it is better to focus on the train based research.

 

Deleted.

 

I think the point that (apparently) NPL made a mistake with their wind tunnel testing of aircraft was worth making, but I agree that further discussion of aircraft here should be avoided.

 

I think though we see it as a mistake now because we are better informed. They were pioneering wind tunnel testing and development.

Of course there were going to be areas of improving their understanding.

 

The 5006 ( Tregenna ) log compiled by C.J.Allen covered part of a GWR high speed exhibition day.
CJA being able to travel threetimes twixt Paddington and Swindon at high speeds.

The log was reproduced in the Railway Magazine
7/1932 p.10
8/1932 p.100 with milepost data.

Not surprisingly CJA included in his seminal Locomotive Performance in the 20th Century p.163

Regarding 7018, (Drsyyllyn) which included a very high speed at Little Somerford and the shortest known
BTM - PDN overall steam hauled time.

Trains Illustrated 1958 p. 487 and 1959 p.433
Modern Railways 8/1964 p.118
RM 1959 p.855
RM 1964 p.563
RM 2004 p.22
RM 2010 p.41

All the above via the excellent ( I would say that wouldn’t I ) Railway Performance Society Archive.

5006 was essentially as per the original design.
7018 with double chimney and four row superheater.

Comparing the Hall with Standard Swindon No.1 Boiler and the Castle boiler seems to me a bit too far.
However if you insist then
5006 with an original Collett Hall
and 7018 with a Hawksworth 6959 Modified Hall with three row superheater.

Michael Rowe

 

Presumably you mean the post April 1958 version of 7018 with four-row superheater, double chimney (fitted in 1956) and 50% more oil than standard. Before that she was regarded as a black sheep. The large plain bearing eccentrics must have been a bit of a disadvantage for high speed running - as for all GWR four cylinder locomotives.

 

Will try this first:

https://www.railwaywondersoftheworld.com/cheltenham-flyer.html

Need a little help.

What is level over sea for Steventown and Twyford? 66 and 45 meter
How many kg is 195 tons
How long was train when the the six coaches and locomotive were running together
Was the stretch windswept or fenced in by tall trees.

 

To the level of accuracy of any model with real passengers and real world vehicles, 195 tons = 195,000kg.

Can't answer the others.

Tom

 

I just came up with 177000 kg !! Uk ton v metric tonne.

If it is any help you can assume the line is falling at 1 in 754 Swindon to Didcot and at 1 in 1508 didcot to Reading. The Didcot to Reading section has a fair amount of curvature. The line then rises a short distance to MP34 and then falls at around 1 in 1000 to Maidenhead.

 

177,000kg would be a 195 US or “short” tons (2,000lb or 907kg).

An imperial ton is 2240lb, or 1,016kg - but near enough 1,000kg.

Tom

 

Still confused but at a much higher level
It was kind of tons used in the very fast log in the Link I gave?