Time for the Daily Update:
My contact has found the exact part number for this piece, but isn't certain it's the exact variation we're looking for. For clarification, the whole assembly seen in the book diagram is the "interconnector", the emitter piece specifically is properly called a "balance pipe".
He says:
>>...it is clear that this is only one of TEN different interconnector "balance pipes" as it calls them, some labelled "small", some "large", that were fitted either as contemporary alternatives to each other, or as product improvements or "Mods". (I do have the manual listing such mods but haven't had time to check it yet). I'll know more by tomorrow, as I need to make sense of the different parts, but I have a strong feeling given the possibilities this opens up, that my rationalisation regarding there being two rings of holes one on top of the other, could quite easily be incorrect. <<
Even if it isn't the exact one he is determined to find the correct one. Since he has access to a manual listing these modifications we may know all of the possible differences soon. I believe the one we want is the "small" variety which should cut the possible variations to 5.
I'm holding onto the part numbers for now. No need to jump the gun on this until we're sure of the exact variation.
Also he's looking into other sources and I don't want to impede his efforts. He is in a better position than any of us to deal with any historical aircraft part sources.
If the one he's found that I've shown is not the exact one, it's darn close.
Some measurements for the comparison to begin:
>>The dimensions of the part I was sure was the emitter; 53.5mm outer diameter and 29.5mm max height. The inner diameter for the inner pipe is 26mm, and the inner diameter of the outer pipe (the shorter one from which protrudes the inner) is 36.8mm. This may be of little help until I discover more.<<
This matches up with my Gav emitter pretty nicely, but I'll leave the detailed measurement comparisons to others.
Other good news, the museum has another Derwent in parts right now for the first time in 30 years. It's going to be reassembled and stay in the museum, but he will check the "emitter" parts to see how they compare with the one found. If those are more correct then we will have pics and measurements for any needed modifications (or know of a variation we want to steer clear of).
IG-88's head is an ongoing tale as well, but this thread is already pretty crowded. I figure I'll wait until I have new pics to share and solid info to start an IG-88 head thread.
Regarding the "scrap" Mark 8 that's been located.
He said:
>>As to the value of the Derwent, I can't offer valuations as such because of our status as a charity and public institution, but £5000 seems a little much for what sounds like a scrap engine. Have you told them that you want it for parts?<<
He plans to report back with "a SAFE model of Derwent {the one we would want specifically for SW parts}, which SHOULD be the Mk.8 since the 5 is clearly different and the 9 had a different ignition system."
BTW - At this point it's still unknown if a full engine would yield 9 exact emitters and 9 exact heads. He has reason to believe that 2 of the 9 heads may be slightly different. (unknown if that means 7 good heads and 2 slightly off or vice versa, OR the variations may be superficial, removable and of no consequence to us).
