What aircraft type used the Watts Propellor??

You can always read the book.

https://www.amazon.co.uk/gp/offer-listing/1331942608/ref=tmm_pap_new_olp_sr?ie=UTF8&condition=new&qid=1536097721&sr=1-1

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The Watts type propeller matched the power, gearing and pitch requirements for a given engine or airframe. For instance the Hind trainer was 10′-10″, Hector 10′-9″, Hardy 10′-4″, or 10′ 6.5″, Osprey 10′-6″ and Hart 10′-4″.. Fury 1, 10′-6″ and Nimrod II, 10′-9″. These are just the diameter differences. I can’t quote the pitch differences.
Most seem to have a Z—— drawing reference number, but the drawings for the Hind Trainer and the Osprey are given as Watts 861 and Watts 883 respectively.

As to the propeller boss which matched the nose cowling, these were not entirely made like the prop of laminated wood, but were usually built up fairings of plywood ,on mahogany frames and rings, which were fixed to the solid propeller centre through, which were holes for the prop shaft and mounting bolts.

The boss was usually tipped with a metal fairing for the Huck’s starter dog or a small domed spinner.

John

Great information that ties a few observations together. Certainly Watts fixed pitch wood props were fitted to Hart biplanes, eg Australian Demon and other interwar aircraft. The Hart biplanes generally had RH tractor RR Kestrels, and so did the HP Heyford, but the Watts prop numbers and props are different in these applications. Mind you the RR Kestrel had different reduction gear ratios/supercharging depending on application, eg Flying Boat versus fighter, and the fixed pitch blades would have to be different too. The Hector, a Hart biplane, also has a different Watts prop, also being LH tractor. My understanding is that different blade designs had different Watts numbers, being different designs. For Christmas, I would love to get data on Watts prop designs, sufficient to be able to reconstruct a blade design model, and compare these with other blade designs. Was the Hector blade just a Demon blade in reverse? Was the LH tractor Hector blade just a LH tractor Bristol Mercury blade ? SBAC had different ‘standard’ prop hubs, not sure if the interwar biplane hubs on Kestrels transmitted to new fangled Merlins on Hurricane I’s. A gent here had half an original Hurricane Watts fixed pitch prop, I was half minded about it, offered him half the price he wanted and was called a half wit.

Thanks Antoni. That explains why the example used on early Spitfires is sometimes referred to as an Airscrew propeller (or, indeed, as an Airscrew airscrew, as the terminology of the time would have it, although I’ve not seen anything quite so awful a reference.)

Which third type? Gladiator? Engines of smaller power had a smaller diameter propeller. Hurricane and Spitfire noses ended in different diameters so the boss would not be identical, unless this is hidden by a spinner on the Spitfire? The prototype Spitfire originally had a smaller diameter propeller, but several different types were tested before settling on the Airscrew product for initial production.

Were the propellers used on all three machines identical? I have always assumed that they were. Diameter of blade and boss etc.

The so called “Watts Propeller” takes its name from the the designer, Dr H C Watts M.B.E., D.Sc., M.Inst. C.E., F.R.Ae.S. He never manufactured propellers or owned a company that did.

After obtaining his degree from Bristol University, from 1911-14, he worked as a Technical Assistant for the Bristol Aeroplane Company. From 1914 until 1919 he was in charge of design and supply of aircraft propellers at the Air Ministry. From 1919 until 1925 a director of Ogilvie and Partners, consultant Aeronautical Engineers. From 1928 until 1932 he worked as an independent consulting engineer. In 1932 he joined the Airscrew Company, Weybridge, Surrey, as technical director. The Airscrew Company manufactured the two blade propellers for the early Hurricanes and Spitfires. So they can be called Watts or Weybridge.

He was the author of The Design os Screw Propellers: With Special Reference to Their Adaptation for Aircraft.

The Spitfire didn’t use a Watts prop, but one described in Spitfire The History as “Weybridge”. Only the first 50 Mk.Is are so described, certainly no Mk.IIs.

Hawker Hinds, Audax,Fury etc.

Gladiator comes to mind.