John Cobb- Crusader/Railton Special

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quicksilver-wsr
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Re: John Cobb- Crusader/Railton Special

Post by quicksilver-wsr » Wed Jul 25, 2018 12:20 pm

Renegadenemo wrote:
Tue Jul 24, 2018 12:30 am
There was also some curious and (I thought) rather heavy design of the outer skins with inner skins attached that were designed to fit snugly into the gaps in the frame. PDS had a selection of these prototype panels and, whereas the frame was made with great accuracy, the fabricated skin panels were never the snug fit intended due to weld distortion.
A quick comment on the above, before the moment passes ...

Ken's outer skin panels were, indeed, rather heavy. But that's because they were going to do a lot more work. Ken had in mind a very much simplified, 'lightweight', spaceframe design. A ladderframe structure that he termed a Vierendeel Truss. It was around a third of the weight, length-for-length, as the K7 spaceframe. So what the boat gained, weight-wise, with the heavy panels, it lost again with the skimpy frame and it would all even out.

It was all very clever. A quasi-monocoque. The spaceframe was only really there to support the panels - not the other way around, as would normally be the case. Ken saw it as an amalgam of K7 and CN7: a sort of cross-breed structure, employing aluminium-honeycomb-sandwich skin panels made pretty much identically to the way the CN7 car was made.

The trick was that the whole boat would become, in effect, one gigantic shear-panel, and therefore be not only very strong but also very stiff in torsion.

Ken put a huge amount of time into it. That's what a lot of his calcs were related to (mind you, there were never any drawings, just sketches). But like everything else at that time, what started out as an elegantly simple design got more and more complicated as Ken put the detail in to make his 'simple' structure work.

The prototype panels you saw at PDS were test-samples made to Ken's spec by our sponsor, Hexcel Composites, at Duxford near Cambridge - a site with strong associations with the construction of CN7. There were two sandwich-panels each of three different weights - six panels in all: the weight varying as a function of skin-thickness. They were never designed to fit into the spaceframe that was eventually built to Glynne Bowsher's drawings. By the time that spaceframe was on the drawing-board, I had decided to totally abandon Ken's construction method, in the interests of getting something built. I was thoroughly disillusioned by then with Ken's plan.

Several sections of Ken's spaceframe structure were built by BOC Gases at Morden in south London, using the T59 tubing made for us by Accles & Pollock, so that the Hexcel panels could be fixed into them and tested for strength in an impressive rig that had been specially built for us at Southampton University: a massive piece of kit that they christened "Samson". These tests never happened, because - frankly - I'd had enough and just quietly let it die.

What a shame Ken's ideas weren't easier to implement. A whole load of work went in for nothing, basically. One of Ken's requirements was that the spaceframe had to be built to "zero tolerance", so that the sandwich-panels would fit in absolutely snugly and act with maximum efficiency in shear. It was, of course, utterly impossible to achieve zero tolerance in the fabrication of such a large spaceframe - and everyone involved, except Ken, knew it.

Nigel

Black Knight
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Re: John Cobb- Crusader/Railton Special

Post by Black Knight » Sun Jul 29, 2018 11:06 am

When I was about 12, I drew 2 boats, using K7 & SOA as a basis but with the twin Olympus engine box from Concorde turned upside down & fitted on the hull. My design tech teacher loved it but thought it’d need the Pacific to run on & not a lake 😂

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Renegadenemo
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Re: John Cobb- Crusader/Railton Special

Post by Renegadenemo » Sun Jul 29, 2018 12:21 pm

The Concorde inlet is a marvel of engineering in its own right...

https://www.heritageconcorde.com/air-in-take-system
I'm only a plumber from Cannock...

"As to reward, my profession is its own reward;" Sherlock Holmes.

'Sometimes you gotta be an S.O.B if you wanna make a dream reality' Mark Knopfler

sbt
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Re: John Cobb- Crusader/Railton Special

Post by sbt » Sun Jul 29, 2018 11:13 pm

Renegadenemo wrote:
Sun Jul 29, 2018 12:21 pm
The Concorde inlet is a marvel of engineering in its own right...
True, but I wish that page was better proof-read and designed. Sadly I no longer have colleagues who worked on that bit who could clean it up for them.

The page is also wrong about Concorde being the only aircraft able to Supercruise. As far back as the Lightening (not for long though - someone seems to have forgotten about space for fuel on that aircraft) it was possible. TSR-2 did it, and today it's relatively common (Typhoon, Rafale, F-22, Draken, Mig-31, Su-35, Grippen NG). She wasn't even the only CIVILIAN aircraft capable of Supercruise, the Tu-144 did it.

Now back to boats...

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Re: John Cobb- Crusader/Railton Special

Post by Renegadenemo » Sun Jul 29, 2018 11:53 pm

TSR-2 did it
Long pondered this one. A small aircraft stuffed with two afterburning Olys and virtually no wing or any other provision for carrying fuel. It surely had to be even more compromised than a Lightning.
I'm only a plumber from Cannock...

"As to reward, my profession is its own reward;" Sherlock Holmes.

'Sometimes you gotta be an S.O.B if you wanna make a dream reality' Mark Knopfler

sbt
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Re: John Cobb- Crusader/Railton Special

Post by sbt » Mon Jul 30, 2018 5:56 am

Renegadenemo wrote:
Sun Jul 29, 2018 11:53 pm
Long pondered this one. A small aircraft stuffed with two afterburning Olys and virtually no wing or any other provision for carrying fuel. It surely had to be even more compromised than a Lightning.
TSR-2 wasn't a small aircraft. It was nearly twice as long and nearly twice as heavy as a Tornado. It was only 10ft shorter than a Vulcan (discounting probe) with around half the Maximum Takeoff Weight of that aircraft.

TSR-2 supersonic time was not limited by Fuel, it was limited by airframe heating. Maximum time was 45 minutes. Total internal fuel load was 5,588 gallons vice c. 1600 gallons internal and c. 1000 gallons external on Tornado.

Design Mission Profiles: With 2000 lb (internal) payload, Internal Fuel only, with normal reserve fuel allowances. Standard: 100 nm at higher altitudes at Mach 1.7, 200 nm at 200 ft at Mach 0.95. 1700 nm at Mach 0.92 (1000 nm operational radius). Low Level (200 ft): 700nm radius.

Exact figures for real missions obviously depend heavily on payload and mission profile (including things like fuel allowed for potentially evading an air-to-air interception and exact diversion airfield location)

During development range was dropped to 650 nm by agreement (no idea what profile, which makes the exact figure somewhat meaningless). This was a cost saving measure, not apparently because the design figures could not be achieved, it would just cost a lot.

quicksilver-wsr
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Re: John Cobb- Crusader/Railton Special

Post by quicksilver-wsr » Mon Jul 30, 2018 2:15 pm

As I mentioned the last time this subject came up, a few years ago, a heavily-armed the TSR2 could carry up to 1,000 gallons of fuel externally, too.

Although the tank, or tanks, were jettisonable, the carriage of additional fuel externally inevitably brought certain operational constraints - but this would apply to any aircraft (and even moreso to a swing-wing type such as the F-111, which was touted as a TSR2 replacement).

Unarmed, in the recce role, the TSR2 could carry even more fuel - in the vacant bomb bay.

Either way, there would have been provision for air-to-air refuelling as well, had development been allowed to advance.

For a sober assessment of the TSR2, a recommended read is at:https://www.rafmuseum.org.uk/documents/ ... dsight.pdf

Nigel

Ernie Lazenby

Re: John Cobb- Crusader/Railton Special

Post by Ernie Lazenby » Fri Sep 07, 2018 8:48 pm

Regarding Crusader. I am really looking forward to Steve Holter's new book getting published. About 15 years ago I contacted Steve to let him know the result of some tests I did with a working model of Crusader I built. I got the boat to 'plough in' exactly the same as the real boat did. I concluded that the then accepted reason for the crash was that the front planning shoe had collapsed was incorrect. I concluded that it was due to the boat bouncing resulting in Cobb being thrown about and unable to keep the steering wheel still, the bouncing resulted in the forward placed rudder momentarily leaving the water then entering again at an angle thus causing the boat to nose dive. Extreme forces at high speed caused the accident.

I will be very interested to read if there is new information in the book that may prove my theory wrong or otherwise. I recall giving a talk at Coniston about the Crusader crash and my theory. Much shaking of the head indicating I was talking rubbish. If I am wrong that is okay, happy to admit it with my knowledge advanced, if I am correct maybe those who shook their heads and dismissed my theory will apologise- I doubt it.

I think many people forget that those who design full size vehicles use working models to help advance knowledge, they are far removed from being 'toy boats as a village idiot once called mine'.

Ernie Lazenby

Re: John Cobb- Crusader/Railton Special

Post by Ernie Lazenby » Fri Sep 07, 2018 8:55 pm

we will know as soon as the book is published- I am aware that since I gave that talk my theory has been taken on board as having some credence.
In the aftermath of the crash it would be easy to conclude the planning shoe had collapsed given the previous experience of problems associated with it. The biggest problem was the boat being 1000ft under water and thus any evidence to support that theory lost..

f1steveuk
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Re: John Cobb- Crusader/Railton Special

Post by f1steveuk » Fri Sep 13, 2019 4:17 pm

I suspect from my silence, you have all concluded I had either died, or was busy, and as you can see from this, it is the latter!!!

The book is currently in the final stretch, design, picture picking and adding two chapters because of exciting developments.

During research, I discovered Railton was very keen to prove his concept was correct, and returning slightly to his and Doug Van Patten's earlier concept, designed a new hull form, which was built as a model, but was never run, as Castrol put it's money into Donald Campbell's Bluebird.

I found the model, and during a during a conversation with Richard Noble, I decided to step aside, and broker a deal for Richard to buy the model. Once Ron Ayers saw it, it was decided to build a working version, to match the large scale Crusader already in hand.

This can be seen at

http://www.railtonwaterspeed.uk/

There's also some exciting news about to become public, but in the U.S. first, for those that can see National Geographic's "Drain The Ocean" series , make sure you watch on September 16th.

I'm now in a position to say, my analysis is 100% correct, just in time!!!!
Steve Holter, UK and France, and sometimes reality....................

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