Bluebird Archive Photos & Films

Post Reply
User avatar
rob565uk
Posts: 808
Joined: Wed Feb 04, 2009 2:02 pm
Location: St Helens, Merseyside

Re: Bluebird Archive Photos & Films

Post by rob565uk » Sat Jun 21, 2014 12:03 am

I agree that the Beryl powered version of the boat has a good overall look to the way it performs. I recall reading somewhere that it was once timed at around 285 mph when the pitot was blocked or failed and Donald couldn't determine his true speed. It kind of makes one wonder if he might have been better keeping the Beryl for the final attempt. Leo and the Team understood that setup very well and given some time and resource, could have really fine-tuned it to extract the maximum performance. Must admit though, I haven't done the maths and don't know if the nominal 3750 lb max thrust of the Beryl would have got K7 over the 300 mark. Unless some kind of additional short term boost could have been engineered - rather like that on the Orpheus version.

When you come to a fork in the road, take it

Terminator
Posts: 696
Joined: Thu Sep 24, 2009 11:19 pm

Re: Bluebird Archive Photos & Films

Post by Terminator » Sat Jun 21, 2014 5:04 pm

286mph Mike not 285 me old mate :D re one way run which was right on the edge and up on the fins. And I must agree with our Ted re-Beryl version and transition into planing position a lot smoother and refined dear boy.
Novie
"Never ride faster than your Angel can fly"

User avatar
sheppane
Posts: 485
Joined: Sat Dec 06, 2008 10:03 am
Location: Chiswick, West London and Penrith, Cumbria.
Contact:

Re: Bluebird Archive Photos & Films

Post by sheppane » Sat Jun 21, 2014 8:06 pm

rob565uk wrote:I agree that the Beryl powered version of the boat has a good overall look to the way it performs. I recall reading somewhere that it was once timed at around 285 mph when the pitot was blocked or failed and Donald couldn't determine his true speed. It kind of makes one wonder if he might have been better keeping the Beryl for the final attempt. Leo and the Team understood that setup very well and given some time and resource, could have really fine-tuned it to extract the maximum performance. Must admit though, I haven't done the maths and don't know if the nominal 3750 lb max thrust of the Beryl would have got K7 over the 300 mark. Unless some kind of additional short term boost could have been engineered - rather like that on the Orpheus version.
Rob,

Re K7's top speed with the Beyrl, we calculated when doing the book that a bare 300mph was the absolute limit. Given K7's average of 286 on the first run in 1956 and 283 on the first run of the 64 record, the peak on both runs would have been just short of 300mph. The team were well aware of the knife edge they were operating on in terms of Bluebird's tendency to climb off the planes and run in ground effect. This tendency was less marked in higher operating temps, with less lift, but also lower engine thrust. In 56, K7 took flight as DC backed out of the throttle at the end of run one, and gave DC one hell of a fright. The ambient temp that September was in the mid teens in centigrade. In 1957, at near zero temp, K7 was on the fins at anything over 260mph. In 64, with a better configuration afforded by the fixed stabilising fin and revised sponson fairings, and a higher ambient temp, K7's performance was just about perfect. The higher ambient temp in the mid twenties centigrade helped make the difference.

Contrast that with low single figure ambient temp on Jan 4th 67, more thrust and a much higher peak speed, K7 had reached the edge and crossed over its safe operating envelope.

Ted makes a good point about K7 appearing to perform that much better with the Beyrl than the Orpheus. This is indeed something which we noticed when doing the book, and I think the team were becoming very aware of the different running characteristics, and that running in very low ambient temp did pose some potential issues.

It's perhaps for that reason that DC always preferred, if it had been possible to go back to Dumbleyung for the attempt on the 300. The lack of finance never allowed that to be a realistic option. The original plan of Coniston in September 66 would have to be the compromise. Little did they know they would still be there in January 1967...
'When you go down into the arena, you know that sometimes, you're likely to get your nose punched. You do it with your eyes open. You take the risks'

Donald Campbell, Bluebird and The Final Record Attempt. http://www.bluebirdk7.com

User avatar
sheppane
Posts: 485
Joined: Sat Dec 06, 2008 10:03 am
Location: Chiswick, West London and Penrith, Cumbria.
Contact:

Re: Bluebird Archive Photos & Films

Post by sheppane » Sat Jun 21, 2014 8:46 pm

An illustration of K7's fundamental problem before the changes made in 58, K7 operating in ground effect in November 57. Those fins don't develop enough lift to hold up a 5000lb craft. 260mph and all the shoes out. (should reading wedges out) Any faster, and K7 would have been airborne at temperatures around 0 degrees C.
10308103_1383368328614143_9004526108007824644_n.jpg
You do not have the required permissions to view the files attached to this post.
Last edited by sheppane on Sat Jun 21, 2014 10:33 pm, edited 1 time in total.
'When you go down into the arena, you know that sometimes, you're likely to get your nose punched. You do it with your eyes open. You take the risks'

Donald Campbell, Bluebird and The Final Record Attempt. http://www.bluebirdk7.com

User avatar
Renegadenemo
Posts: 4355
Joined: Mon Dec 01, 2008 12:29 pm
Location: N E England
Contact:

Re: Bluebird Archive Photos & Films

Post by Renegadenemo » Sat Jun 21, 2014 9:37 pm

260mph and all the shoes out.
A small bit of nit-picking in the interests of technical accuracy - the 'shoes' are the surfaces that cover the forward, sloping face of the underside of the sponson only and they end at a small step where they meet the 'float wedges' on which the boat actually runs.
Shoes.jpg
It's easy to see why they were nicknamed shoes and they are described as such on the drawings.
You do not have the required permissions to view the files attached to this post.
I'm only a plumber from Cannock...

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

Voltaire's apology when he wrote a long letter: "I didn't have time to make it shorter."

User avatar
rob565uk
Posts: 808
Joined: Wed Feb 04, 2009 2:02 pm
Location: St Helens, Merseyside

Bluebird Archive Photos & Films

Post by rob565uk » Sat Jun 21, 2014 9:49 pm

Neil and Bill

Thanks for the informative responses. I have looked at that picture of K7 before but never put that particular interpretation on it - fascinating and thought-provoking.

When you come to a fork in the road, take it

User avatar
Mike Bull
Posts: 4399
Joined: Mon Dec 01, 2008 1:57 pm

Re: Bluebird Archive Photos & Films

Post by Mike Bull » Sat Jun 21, 2014 10:04 pm

Renegadenemo wrote:
260mph and all the shoes out.
A small bit of nit-picking in the interests of technical accuracy - the 'shoes' are the surfaces that cover the forward, sloping face of the underside of the sponson only and they end at a small step where they meet the 'float wedges' on which the boat actually runs.

It's easy to see why they were nicknamed shoes and they are described as such on the drawings.
Yes it's a small point, but it does help if everyone understands which part of K7 is which...shoes are yellow, wedges are blue...
00.jpg
You do not have the required permissions to view the files attached to this post.

User avatar
sheppane
Posts: 485
Joined: Sat Dec 06, 2008 10:03 am
Location: Chiswick, West London and Penrith, Cumbria.
Contact:

Re: Bluebird Archive Photos & Films

Post by sheppane » Sat Jun 21, 2014 10:31 pm

Mike Bull wrote:
Renegadenemo wrote:
260mph and all the shoes out.
A small bit of nit-picking in the interests of technical accuracy - the 'shoes' are the surfaces that cover the forward, sloping face of the underside of the sponson only and they end at a small step where they meet the 'float wedges' on which the boat actually runs.

It's easy to see why they were nicknamed shoes and they are described as such on the drawings.
Yes it's a small point, but it does help if everyone understands which part of K7 is which...shoes are yellow, wedges are blue...
00.jpg
Guys,

Good point, well made. My bad.

Hopefully the point is made, that with the Orpheus, K7 was much less of a know quantity, and with different circumstances in the very early autumn, the team could have got on top of some of the issues that developed. One point I missed is that the greater power of the Orpheus was meant to get K7 to 300mph quicker and therefore the elapsed time in the 'zone > 290mph would be less than with the pretty much maxed out Beryl. It also meant Coniston was still just about suitable as a venue - K7's acceleration tailed off significantly north of 280mph with the Beryl.
'When you go down into the arena, you know that sometimes, you're likely to get your nose punched. You do it with your eyes open. You take the risks'

Donald Campbell, Bluebird and The Final Record Attempt. http://www.bluebirdk7.com

User avatar
Renegadenemo
Posts: 4355
Joined: Mon Dec 01, 2008 12:29 pm
Location: N E England
Contact:

Re: Bluebird Archive Photos & Films

Post by Renegadenemo » Sun Jun 22, 2014 1:45 am

Hopefully the point is made, that with the Orpheus, K7 was much less of a known quantity
I think we can all agree on that one and hopefully we'll come to understand more about the Orph' installation once we get it working again. One possibility for which we may be able to provide reasonable supporting evidence is that Donald didn't stop to refuel at the end of the first run because he didn't have enough gas in the start system to get the engine running again if he had. He'd already carried out a cold start then a relight at the end of the run. From what we've observed when working the system back up he almost certainly wouldn't have had enough gas to guarantee another start and he'd have known as much and would therefore never have dared stop and take the chance.
Neil, in the course of your detailed research you've studied the first run frame by frame, second by second, is it possible to say how long the relight took and give us a plus or minus on your estimate? That would be very useful.
I'm only a plumber from Cannock...

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

Voltaire's apology when he wrote a long letter: "I didn't have time to make it shorter."

User avatar
mtskull
Posts: 582
Joined: Thu Jan 21, 2010 10:32 pm
Location: West Yorkshire

Re: Bluebird Archive Photos & Films

Post by mtskull » Sun Jun 22, 2014 8:17 am

Renegadenemo wrote:One possibility for which we may be able to provide reasonable supporting evidence is that Donald didn't stop to refuel at the end of the first run because he didn't have enough gas in the start system to get the engine running again if he had. He'd already carried out a cold start then a relight at the end of the run. From what we've observed when working the system back up he almost certainly wouldn't have had enough gas to guarantee another start and he'd have known as much and would therefore never have dared stop and take the chance.
Said it before, but I still think that possibly too much is being read into DMC's words "lighting up" or "relighting", at the end of the first run. Rather than imply that he had initiated a full start sequence, IMHO it be more likely that he was simply reporting what he was observing, i.e. reducing rpm & egt, which would have been restored as the igniters did their job and the fuel system caught up with the reduced demand. In the event of the engine running down beyond the point at which a relight could be achieved, it would have surely been more logical to allow the craft to stop, refuel as planned, take a breath and then restart. To look at it another way, there wouldn't have been any point in wasting compressed air on a restart at the end of the first run unless it had already been decided to commence the return run without refuelling.
Obstacles are those frightful things you see when you take your eyes off your goals.

Post Reply