Oracal, a fantastic document, thank you. The apparatus seems functional for a simple blade of fixed aerofoil section, but not sure how it would handle twist or varied aerofoil sections, which were evolved by the 30’s and for 40’s aluminium blades. I could do a Fairey-Reed type, prior to giving it a twist. A great document to see. The journey was not done on a whim, but a bhim, which is a combination of bet and whim, based on probability and confluence of domestic duties and geography. I had to take the kids to a rural camp, so this was a Dad treat – diversion on the way back. The skill of combining domestic duties with treasure hunting is sadly under appreciated as an Olympic sport, but most effective aerophiliacs would be up there on the podium, I reckon. 

A very wonderful bibliography Oracal ! A brewery’s worth ! Is the AP list held anywhere ? Does this extend to the Hawker Hector ? 

These are the arms from a suspected 4 bladed test club marked ‘Bristol Hercules’. Each arm is approximately 5 foot high and as thick as an elephant’s leg. It would make a huge test club, worthy of a 1,000 HP test rig. Perhaps it could be used for the current craze for indoor sky diving centres. The evidence of Kestrel hub drilling jigs and a Bristol Hercules test club suggests the ‘Ellis-o-Matic’ was capable of duplicating very large propellors, as much as for more modest applications like the Tiger Moth or Avro Cadet used for training. This contraption is currently in pieces, and as the months go by I will try and share progress with its reconstruction. One day, there I will be, smiling, with bloody stumps for hands! 

‘Ellis-o-matic’ duplicating blanks. The ‘half’ was enough, as the ‘work’ could be turned around to cut the other side. Some of these are Tiger Moth and Gypsy Moth, with hints at pitch and dimensional variations. That these survived is a minor miracle. 

Now there is a little country town in Australia that barely deserves the description of a town. It is loathed by tough cattlemen because it does not even have a pub, and there is nothing to suggest to the driver lost from the closest main road that there is anything to stop for. Just a decrepit flash of rusty, weedy buildings that might house suspicious country folk with guns, and lost willows gripping yabby holed, eroded creek banks teeming with hungry snakes. And it was into this rural idyll that Australia’s pre-eminent diviner of lost aeronautica drove into, perchance, and being equipped with more eyes than a fly spotted an old sign suggesting an antiques store. Prudent folk would not stop. To preserve the mystique, we shall call him ‘The Baker’. Now the Baker followed the sign, like some doomed sailor in thrall of sharp toothed Sirens, following an unpromising, dusty track to a building that might sustain a conspiracy to dismember lost strangers.  First appearances can be unfair. For inside was a most courteous proprietor, with a treasure trove of delightful, quality merchandise, procured from quality foraging. “Do you have any aeroplane stuff?” the Baker asked, after preliminarily courtesies were fulfilled. “Yes”. And so the Baker became Howard Carter, and so the old shed became the tomb of Tutankhamun, for those concerned with the matter of Perfectus. Like all treasure tombs it was not obvious, in the first gloom and dishevelled debris of old tin cans, matronly furniture and rabbit traps, that pure gold lay in careless abundance, but it was enough for the instincts of the Baker to be aroused. There were old timber propellors stacked on a dusty shelf. Not propellors, mind you, half propellors, awkward and disappointing for a ditzy interior designer to display as a conversation piece on a wall, but obvious to the Baker that they were patterns, from some forgotten atelier’s workshop. The Baker is more of a WW2 variable pitch prop kind of guy, but sufficiently tutored to make accurate, scientific observations, and connect these with a network of grasping, desperate collectors like me, as individual bias of the client base suggests itself. In the analogy of Egyptology it was a tomb, but of a Prince or pauper, to the Baker, unknown. The Baker, as is the method, safely returned, and later conveyed this information to me, and the hairs stood on my neck. By gentle compliment, then pleading, then threat, then begging, the coordinates were given to me, and I instantly mounted an expedition, as by context of history, geography and faint pencil sketch, this could only be Perfectus, or at least some equally promising interloper, like a Larkin or 1960’s clearout of a hitherto unknown artist. I have been in the game long enough to know that each slender rumour must be followed through, because for every dozen disappointments, there are crowning peaks of discovery to be made, that reward astonishingly, and turn the foolish expedition into the sublime moment. So the dog and I loaded ourselves into the ute, and set out on the road. 

CD and Oracal, please do not Meghan this thread ! Rumours of it’s death are exaggerated, as Mark Twain might have said. I have used a bore gauge to explore whether the Rapier cylinder bore shows the same tapering and it appears not. I wonder if this is a tweak that carried over to the Sabre design of it was a problem only with early Y alloy pistons, superseded by the evolution of low creep piston material. Certainly machining tapering bores would have added complexity and hints at the reason why Napier engines are beloved by engineers and loathed by accountants. I am grateful for the posting of any information on the topic and any interest shown in it. Any poster wins a beer, but due to distance, quarantine and convenience considerations, I must drink this, in sufferance, on your behalf, but it is the thought that counts !