Edward Thompson: Wartime C.M.E. Discussion

The Lightning and the F-4 were designed to do somewhat different jobs. Lightning as a point defence fighter, the F-4 as a Naval multi role aircraft. Comparing the two is akin to comparing apples with oranges.

 

And, more likely than not, with all the detail design done by the same people.

 

True, but it's quite plausible that two such aircraft roles might come into operational contact (as the F4 did with various MiG's over North Viet Nam). It would be interesting to see how the two measured with Boyd's Energy–Manoeuverability theory.

Oooops, I'm way off-topic - sorry all!

Noel

 

I'd be surprised if that description was used against the Stanier 2 and 3-cylinder 2-6-4Ts or the Fowler & Fairburn 2-6-4Ts. I've only ever heard that said about the Fowler and Stanier 3P 2-6-2Ts, which were nicknamed Breadvans for the very reason they could only produce enough steam to warm a few loaves...
I'd be interested to read the entire quote, and its context, if you know who made the quote and where.

Richard.

 

if you haven't already watched it. Oops, sorry, even further off topic, but that's a good channel for aircraft performance stuff. And across the whole channel, you could probably draw some analogies about "best" depending really closely on what you perceive to be of value, but I'm too lazy.

Tom

 

To clarify again. Yes, it was about the 2-6-2s not the 2-6-4s.

The quote was deliberately out of context to emphasize the weakness of using a single pithy quote as evidence about the merits of a whole type of loco or the work of a designer. Unfortunately, it has been taken as a serious comment about the LMS tanks rather than a comment evidence and argument.

As this is the third time it has been taken literally I think I am going to have to go back and make my point more explicit.

 

On a side note...and on topic...!

Provided I get the edits done by the end of May, the book will be printed - and then published - by early September. I had a very good conversation with my publisher on Sunday and editor and am feeling very pumped for getting the book out there.

There has been one major change, of which I am trying to explore a range of options. The full dataset for the Availability Statistics (as created from the LNER's Use of Engine Power) document, is not viable for full publication. I have been asked to produce a shortened alternative with a graphical slant for inclusion as a new Appendix 4.

I am producing an array of options to that end, and obviously will discuss my approach here when I have more details. But the main idea is to give comparison data for the following classes specifically:

• Gresley conjugated classes
• Thompson designs
• Similar pre-grouping locomotives
• War department designs
• Any specific designs of interest

As it will now not be possible to showcase the full dataset, I have asked my publisher to investigate the possibility of producing the full dataset as a separate pamphlet for people to read at their leisure.

Your thoughts, as ever, are appreciated.

 

I might be a bit strange, but I do rather like the A10 from an aesthetic point of view, it’s meant to do job so it’s designed like that, plus I really wouldn’t want to say it’s ugly to it’s face!

 

Were Phantoms capable of all weather Mach 2 interception?
And If I could also point out what was the quote about Phantoms looking like they were built upside down?

 

Cue my earlier suggestion re producing a 2nd complementary book. In terms of comparison why not compare the A4s against the A2; the V1 / V3 against the L1; the 04/6 (Gresley) against the 04/8 (Thompson rebuild); or the 04/3 (ROD) against the Stanier 8F (MOS) against the Austerity 2-8-0 (WD).

 

Sorry, I must have missed your original deliberately out-of-context post - I sometimes don't get chance to check the forum for quite a while. Not wishing to rake over old discussions!

Richard.

 

Post #4457 quoted 2630 gallons for the L1s and 2000 gallons the LMS and BR 2-6-4Ts. The 630 extra gallons would add less than three tons to the weight, spread across all the axles. Where did the rest of the extra weight come from?

5ft 9in to 5ft 2in is only a 10% difference. How significant would that be? And would the shorter rigid wheelbase make much difference, given the guiding wheels at both ends?

 

It’s the circumference of the wheel that is in touch with the rails not it’s diameter. Try 2pi R on both wheel sizes and you will find the difference is more than 10%, there were reasons why the 9Fs had their speed limited . On a two cylinder loco the piston thrust will set up horizontal rotary forces around the big end “, the shorter the wheelbase the more it will be accentuated. For an illustration watch 1501 working hard on the SVR

 

Surely the circumference of the wheel pi * D ? So the relative circumferences are 390" and 433" and the second about 11% larger? But that's only one tiny element of the design, there are so many other factors. If one were interested in the topic it would be interesting to compare time between repairs on the class over its lifespan, as there was a lot of cross-fertilisation in the subtler design features in BR days, and one wonders if improvements may have been made. After all a bad reputation is a lot easier to gain than lose.

 

Yes you are right, too early in the morning! The fact remains though that the difference can be critical. The L1s required a lot of maintenance when working services they were designed for. One reason why Neasden got rid of them when LMS tanks became available.

 

Pi R squared is the wheel area, not the circumference - not an especially useful measure! For two locos doing the same linear speed, the number of wheel revolutions per minute is proportional to the diameter, as @MellishR says - not a massive difference between 5'2" and 5'9".

But there are all manner of subtleties of design, many of which aren't apparent just in raw dimensions. A few years ago we had what would amount to a trivial failure of the vacuum brake steam supply pipe on No. 847, but it was the very devil of a job to fix because the pipe was routed internally through the boiler and required substantial stripping to repair. On a BR standard it comes straight off a manifold near the cab and is routed from there externally, and the same failure could have been fixed in the matter of a day or so. In an era of low labour availability, "design for maintenance" is every bit as important as whether a locomotive could do 100mph under ideal conditions - or whether it actually looked aesthetically pleasing.

Tom

 

I want a source and a dataset for this claim John. Give us the information to back up your claims.

And a source/reference for this too please.

 

How much say did the individual sheds have in their locomotive allocation? It feels like the sort of thing that would be largely top down.

 

The F-4 was certainly all weather and a very capable bit of kit but was never intended to be a dog fighter. The military assumed that its array of A2A missiles would take care of any opposition. Sadly many US pilots over Vietnam found out to their cost that the experts were wrong. This prompted changes in design, a gun was added to the F-4s weaponry, and the inception of the US Navy "Top Gun" programme to teach pilots tactics to deal with the Viertnamese MiG fighters. We are way, way off thread now though.

 

The wheelbase isn't that different to many other tank locomotives of this wheel arrangement. I want more than apocryphal stories. I want sources, reports, statistics. The claims being made are literally opinion driven rather than backed up with primary evidence.

Where's that quote, in what book, and what context? I have copies of Top Shed here amongst other books and the amount of info given on the L1s doesn't come across the same way to me.

I want facts John. I want something, somewhere - a smoking gun - that tells us that this is true. The L1s were not withdrawn en-masse until dieselisation was onset and they were displaced from their duties by diesels. That is factual.

If they weren't up to the job they were designed for, why were they still doing the job they were designed for (in 1945) in 1962 (that's 17 years of apparently not doing the job!)