Here at last is some info from gunston’s ‘Fedden’.

Pages 244 – 248 has information, diagrams and comparative drawings of both the Orion and a 4 row 28 cylinder 5 3/4 in bore by 7 in stroke engine.

The Orion was basically a bigger Centaurus, ie 18 cylinders in two rows of nine, 6 1/4 in bore and 7 1/2 in stroke. It was expected to achieve 4000hp.

The unnamed 28 cylinder does not appear to be a ‘corncob’ design from the diagram, it looks similar to the BMW 803 layout – ie row 3 is directly behind row 1 and row 4 is directly behind row 2. However, although it has Centaurus bore and stroke, 28 cylinders means 4 rows of 7 rather than 4 rows of nine so there is more room for the air to circulate. It is also noticable that the cowling outline is well clear of the cylinder heads – again giving more circulation room – whereas Hercules, Centaurus and Orion were (or were to be) very closely cowled.

Here are links to the drawings of the Orion, 28 cylinder engine and a couple of other interesting tidbits from ‘Fedden – The Life of Sir Roy Fedden’ by Bill Gunston. A fascinating book, I recommend it.

I apologise for the large file sizes but there is a lot of detail and some tiny printing I thought might be useful.

http://i115.photobucket.com/albums/n291/nsumner/PP246top.jpg

http://i115.photobucket.com/albums/n291/nsumner/PP246lower.jpg

http://i115.photobucket.com/albums/n291/nsumner/PP247top.jpg

http://i115.photobucket.com/albums/n291/nsumner/PP247lower.jpg

http://i115.photobucket.com/albums/n291/nsumner/PP255.jpg

Obviously this is copyright material so personal use only! 🙂

I’ve contacted the Bristol Branch of the Roll Royce Heritage Trust at Filton, if and when they reply I’ll post the info here.

Thanks for the replys, at some stage though, someone must have put a figure on the cost of each aircraft, the accountants wouldn’t be happy if they didn’t!

RAFM Hendon has the two aircraft delivery ledgers and also the Aircraft Movement Cards. It does not (to my knowledge – but I’d welcome being corrected) have any material contractual records.

Hendon does or did have some contract records back in 1999 but its possible that they’ve been moved. I live in Canada but was planning a visit to the UK to research aircraft costs and emailed back and forth with them about it. (When I finally got to the UK chasing around after my family ate up all my time and I never got to do it… 🙁

The primary contract ledgers are held at the National Archives in the SUPP (for Ministry of Supply) class.

That is very helpful information, thank you.

There is also useful information on contracts in Treasury files and in the records of the 3 main executive bodies responsible for RAF procurement.

I don’t mean to be a pest but you wouldn’t happen to know which treasury files? Also – who were the executive bodies responsible for RAF procurement?

I will post pix of the room under the seat of P3554 if you wish later.

That would be great if you have the time.

Many thanks.