Technical Talk

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Renegadenemo
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Re: Technical Talk

Post by Renegadenemo » Fri Apr 13, 2018 12:21 pm

Don't forget also that we haven't filled the sponsons with expanding foam, which saves about 36 kilos at the front end. Plus, we have the option to tweak the thrust line a little in our favour by adjusting the angle of the engine. Only a degree or two before the inlet trunk becomes the limiting factor but enough to make a difference. This of course would have been disastrous for record breaking but we can do it. And if all else fails l'm sure the army can rustle up a couple if sand bags. We'll get it working one way or another.
I'm only a plumber from Cannock...

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

I have wrought my simple plan
If I give one hour of joy
To the boy who’s half a man,
Or the man who’s half a boy.

Sir Arthur Conan Doyle.

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Canopener Al
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Re: Technical Talk

Post by Canopener Al » Fri Apr 13, 2018 11:50 pm

Cheers Mike and Bill, good answers indeed. Didn't realise the foam was not being added, some serious trimming options open then. Hope what is planned for the weekend shift is progressive. Alas tomorrow it for me is play on the paid stuff, then get my restortion progressed on Sunday.

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Richie
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Re: Technical Talk

Post by Richie » Sat Apr 14, 2018 11:57 am

I love auto correct :)
Clarence come out ov zat tank at vonz !

Vernon
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Rebuild / cockpit

Post by Vernon » Thu May 10, 2018 11:33 am

Hi bill / team
Just a quick one regarding a previous pic of the day cockpit view. How close to the original is the new seat & harness as it was mentioned it was more comfortable than the original? & was it really necessary to alter the position of the seat?
Thank you
Vernon

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Mike Bull
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Re: Rebuild / cockpit

Post by Mike Bull » Thu May 10, 2018 3:59 pm

Hello,

The harness is exactly what Donald had with the (current) exception of the 'Irvin' labels. It is mounted in the same positions behind the shoulders, but is mounted differently on the lower points; these are now solidly bolted into the lower frame tube, rather than being bolted through the 1mm side walls of the seat pan!!!

Donald's seat cushion sat him both higher and further forward, and has been replicated for static display, but both our drivers are much taller and need all the extra space they can get! Hence the new, temporary, different seat pad.
'I am not what is called a "civilized man", Professor. I have done with society for reasons that seem good to me.'

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sheppane
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Re: A stupid question .. Or maybe not.

Post by sheppane » Thu May 10, 2018 9:26 pm

Canopener Al wrote:
Fri Apr 13, 2018 1:03 am
Just seen the lead weights appear on the last picture of the day. That picture has raise a question in my head that has been lurking for some time about the restoration of K7. Of course those lead weights had to be added because the money Donald had didn't include during the 66 modifications to actually do the maths accurately to rebalance the boat without trial and error. I would have doubted that the actual weight and moment of the craft was actually worked out until its first trials in late 66 that proved the trim was way out. Of course K7 is not the same trim as the 4th of July 1967, it has half the world supply of polysulphide sealant on it, plus lots of addition metal to repair the holes. I would doubt the trim is anything close to allowing sucessful planning to happen first attempt. While trial and error may only be the solution with funding and outside help, has anyone asked outside help in weight and balance and if anyone in the right field could stick weight and moment calculations into a suitable program to say.. "Stick X pounds there and the thing will rise? Of course if the budget says no, simple answer is go and play..
Bear in mind that one of the considerations in the 1966 refit was to move the centre of gravity forward to allow the boat a bigger safe operating envelope. This work was done by Ken Norris and John Stollery. They envisaged that the extra power of the Orpheus would be sufficiant to get K7 on to plane, providing the engine did not get overwhelmed by water entering the air intakes. That it did not work out as planned should not be seen as lack of thought in the modifications. A down on power Orpheus did not help in the initial trials of November 66. Please feel free to read the full story in the book that I wrote with Keith Mitchell.
'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

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Mike Bull
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Re: Technical Talk

Post by Mike Bull » Fri May 18, 2018 9:45 am

An interesting nugget- having just put the first one together, I now know that a '67 spec spray baffle weighs in at 8kg!
'I am not what is called a "civilized man", Professor. I have done with society for reasons that seem good to me.'

Vernon
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Rebuild / tail fin

Post by Vernon » Mon May 21, 2018 11:38 am

Hi team
Just watched latest progress video.. excellent as alway & the work you have all achieved is incredible.
A quick question relating to the tail fin.. the rod that protrudes outwards.. what actually is it for?
Thank you
Vernon

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Richie
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Re: Technical Talk

Post by Richie » Mon May 21, 2018 2:41 pm

Vernon, it is the pitot tube and is connected to a speedometer within the cockpit.
Clarence come out ov zat tank at vonz !

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Engine 711
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Re: Technical Talk

Post by Engine 711 » Mon May 21, 2018 5:11 pm

Richie wrote:
Mon May 21, 2018 2:41 pm
Vernon, it is the pitot tube and is connected to a speedometer within the cockpit.
Strictly, I believe its an Air Speed Indicator (or ASI) - https://en.wikipedia.org/wiki/Airspeed_indicator

Air Speed is determined from the difference between the static air pressure and the dynamic air pressure (the air pressure due to the boat moving forwards).

Pictures show K7's ASI above the steering 'wheel', at the top of the panel, slightly offset to port (or left...) - and clearly calibrated in MPH.

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