The Sponsons Thread

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Mike Bull
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Re: The Sponsons Thread

Post by Mike Bull » Fri Mar 22, 2013 6:10 pm

Great stuff, had hoped you'd make it and get that done today. :D

It's worth mentioning that there's not been any one balls up on the sponsons, more a collusion of tolerances, and the fact that while all the central bulkheads were specified to the nearest nano-smidge of Ye Olde Imperial Inches by Mr Norris, the spar frames were not; somewhere in there, we got a tad fat. It'll fix.

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Renegadenemo
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Re: The Sponsons Thread

Post by Renegadenemo » Fri Mar 22, 2013 6:43 pm

You get three bulkheads at the pointy end set out to the Nth nano-smoot, then a gap, then another seven uber-accurate ones, then another gap then a final accurate piece right at the blunt end.
What you do next is squish six chunks of guesswork into the front gap and seven into the back onto which the spars eventually attach. Somewhere in among that lot we managed to grow the sponson an eighth of an inch too wide in the guessed bits. Now considering that MKW's machines didn't lose the plot by an eighth of an inch we discovered the problem when sticking a sponson to a planing wedge. Ironically, there's good photographic evidence to suggest that the samlesbury boys had similar troubles and bodged a fix but it's far from conclusive so we're doing a proper fix.
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Richie
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Re: The Sponsons Thread

Post by Richie » Fri Mar 22, 2013 9:26 pm

98998d3759c5153bf5c2cb79dfd04733_zps5d4de6e3.jpg
"Sponson datum's.......they're not to be messed with, Mike messed with the datum's and look what they did to him !"
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Renegadenemo
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Re: The Sponsons Thread

Post by Renegadenemo » Sat Mar 23, 2013 8:29 pm

Cracking shot of Mike there... We got the sponsons back under control today. Phew!
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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Dominic Owen
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Re: The Sponsons Thread

Post by Dominic Owen » Sun Apr 07, 2013 4:26 pm

I've a sneaky feeling I know exactly what the answer to this is going to be but, just out of curiosity, why does the rearmost bulkhead on one sponson have two round lightening holes and the other a single large oval one? My money is on something along the lines of: "No idea, they weren't drawn that way but that's how the originals were made".
One by one, the penguins are stealing my sanity...

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Mike Bull
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Re: The Sponsons Thread

Post by Mike Bull » Sun Apr 07, 2013 5:31 pm

Great question!

Bulkhead 'A' was drawn to have the two round holes as you've seen, and indeed the first pair we made both had the double holes. Then there was I perusing some crashed sponson pics in the workshop one day early in the process when I thought 'Hang on a minute...' and called for Mr Smith to break the news that one of the originals had been different!

It's Righty sponson that has the slot in the rear bulkhead, and in the high-res images of it post-crash you can clearly see where it's been cut and welded- so presumably, it was made originally with the twin holes (which are just too small for you to get your hand through) but there was a subsequent need to get inside that last compartment, so the holes were cut out to form the slot. Lefty remained with the twin holes, and even though you'll eventually never see them, we've copied this arrangement in the new ones for accuracy.

Mark Elvin
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Re: The Sponsons Thread

Post by Mark Elvin » Wed Apr 17, 2013 7:31 am

Those planing shoes look very nice, what's the finished weight vs billet weight like?

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Renegadenemo
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Re: The Sponsons Thread

Post by Renegadenemo » Wed Apr 17, 2013 9:53 am

Those planing shoes look very nice, what's the finished weight vs billet weight like?
I'll have to re-check the exact figures because the ones I have are prior to a change made to the CAD model after we realised we'd initially worked to an earlier drawing but the billets are a shade over 350kg and the finished parts are a shade under 49kg - that's a shedload of swarf!
I'm only a plumber from Cannock...

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

I have wrought my simple plan
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Sir Arthur Conan Doyle.

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Re: The Sponsons Thread

Post by Mark Elvin » Wed Apr 17, 2013 2:23 pm

Renegadenemo wrote:
Those planing shoes look very nice, what's the finished weight vs billet weight like?
I'll have to re-check the exact figures because the ones I have are prior to a change made to the CAD model after we realised we'd initially worked to an earlier drawing but the billets are a shade over 350kg and the finished parts are a shade under 49kg - that's a shedload of swarf!
Similar "buy to fly" as our diffuser floor section then, 500kg billet down to a shade under 50kg!!!

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Renegadenemo
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Re: The Sponsons Thread

Post by Renegadenemo » Wed Apr 17, 2013 9:42 pm

Similar "buy to fly" as our diffuser floor section then, 500kg billet down to a shade under 50kg!!!
We got lucky because the wedges and shoes are long rectangles but those sections you showed look like they cover a lot of ground. I know what ours should have cost too so yours must have been an arm and a leg!
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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