V Line

----------------------------------------------------------------------------------------------------------- Middle East HQ communiqué issued. Contents as predicted/imagined. Clever wording though. Nevertheless, If a radius is taken from the mid- point (line of thrust/prop centre) to the outlier the nose collar shape can in no way be described as circular. You then put a circle (spinner back plate) with dome (spinner shell) on top and it’s very difficult to interpret/conclude anything from photos. As you asked, re the measurements: 1. None 2. Yes-verified. Moving on, we are all getting older, and sometimes things can understandably slip a little. In view of your initial comment I therefore thought it may be helpful to remind you of my original post: Hurricane Mk I–‘Spitfire’ Rotol Spinners Fact or Myth? ‘That Spitfire (bulbous Rotol) spinners or ‘props’ were used on Hurricane Mk I’s appear to be generally accepted as a fact. Is anyone able to provide documented references to support this?’ Quite straightforward. Attention catching headline perhaps, but aggressive? Do I refer to Hurricane nose collars in any way? The latter is actually not central to my question and not something I raised. I asked he question because, having looked at the matter in some detail, I thought I must be missing something given the received wisdom. Experience tells me this is your preferred ruse when it suits you, but please don't confuse or deflect from the issue. So far no one has come forward with anything that is remotely close to a documented reference or even a plausible argument in support. Not a problem to me, although I did not anticipate the degree of discombobulation my question would cause.

If you have taken my comments on photos personally, you shouldn’t have. You actually do an excellent job with your output which I have found of great value. The nose collar shape is a particularly difficult one to follow. I think it was you above who cited Bentley’s comments/article mentioning same. On the point you made, I do not disagree and of course use photos, particularly on details. You may recall I sent you a number some time ago to illustrate Hurricane blade types. My point on this occasion was principally in respect of dimensions which are particularly difficult if not impossible to gauge. In my opinion (particularly with a zoom on the nose), perhaps the most useful shot of the Hurricane nose and ES/6 in context is within the following photo: No oil deflector ring to obscure/distort the shape. Almost completely side on. Bear in mind the collar join line, just below the screws, is, to all intents and purposes, on the line of thrust. Superb photo but it will not give you dimensions. From directly head-on, I agree with your proposition that there is a lip south of the projections but I haven’t found a photo of the entire opening which is open, without a prop in place and which definitively shows the full shape. To my mind,oblique photos give misleading impressions. I have, though, been up close and personal and do have measurements. I don’t have a radial plan drawing of the opening but at mid point the diameter is less than the height by around ½ inch. Even if this is accepted as fact, I can imagine there may be pontificants proclaiming from Middle East HQ that this is indeed evidence of a circular opening. I may even be accused of measurement crime (strictly prohibited!) or reported for bruising someone’s armour propre. Irrespective of that, moving to more detailed interpretation of photos, we then have the differing base diameters and other characteristics of the ES4/5 and 6 spinners (and relevant blades). I sought to give an explanation of the details in my post above by reference to the Rotol RX Manual although I'm unsure as to whether or not anyone took the trouble to consider what I had written. I hope the above helps. Finally, I make the simple observation that the thread has been diverted to a topic (Hurricane nose collar) which tangential to the question I posed.

Well of course the spinner is circular. The opening isn’t. Not by much, couple of percent in one direction, but it isn’t. No problem with robust exchanges, but keyboard unpleasantness in recent posts reflects rather badly on the posters concerned. I have set out details from the relevant Rotol manual with a commentary/explanation. My research is original and undertaken over several years. Rather than photographs I rely upon contemporary documents and where possible, measurements of the real thing(s).If any reader chooses not to accept my conclusion that’s fine, but they will continue to labour under a misapprehension. Responses: Milne Bay – Highly amusing. Are you here all week? I will say that the spinner backplates sit marginally forward of the nose collar and thus when photographed from ahead, the relationship (which is influenced by perspective etc) is distorted. I made the point above that the form is best viewed on a side-on photo if you can’t get to the real thing. On photos, this is probably the root of the matter as they are often misleading and are invariably not benchmarked to factual detail. How can a difference of say, ¼ inch in one or another plane be identified? Furthermore, if the viewer doesn’t understand what he is looking for/at it’s easy to draw a misleading or false conclusion. Stevehnz- Oil leaks. Quite possibly/probably both but dH seems to have had a reputation. Funnily enough, it appears Rotol’s foray into electric props was partly on the grounds that oil leaks would be avoided. On Rotol v dH, the props are quite different, hub size, blade construction and so on. I had hoped that the Rotol detail I set out above would explain.

I suspect I will be poo-poohed for this but I will not provide dimensions in this instance. My approach to posting on this site is to provide factual data and considered opinion with references where appropriate. I regard it as a site of record and take this seriously. With a careful look, your photo quite usefully shows the disparity between the width and height of the opening.

Circularity - Dimensionally it is not so. A look at the side views of the ES/6's will help readers understand this, bearing in mind the join of the two-piece collar is roughly the line of thrust. Rotol/CSA - yes, there are two methods of fixing but the Luftwaffe stuck with the VDM! (as did the RAF on a variety of types). Thing is, there was not a happy relationship between Rotol and CSA management and this perhaps clouded judgement. There was also the matter of commercial advantage.

The nose ring is a complicated shape and I can assure you is not circular. HC-452 has a Spitfire spinner as confirmed by the stampings. This is logically the same spinner as shown on some of the early Hurricanes in France and also L1669. There is a specific dH spinner for the Hurricane which fits within the collar opening. This is essentially the same as the Watts spinner/hub diameter and also, I believe, the Rotol ES/9. For some reason it appears there was an early supply issue hence the dH Spitfire spinners. Note however that in this instance the hubs and blade root diameters were identical. As I mentioned above, Rotol thought the ES/9 superior but I have found no specific given reasons. It is worthy of mention that the CSA spinners were highly regarded and continued in use on both Spitfires (3 and 4 bladers) and also Hurricanes 3 bladers.

1 .Hub dimensions. 2. Basic design of VDM spinners – not unique. See spinners on Merlin Whitleys (search IWM). 3. Hurricane nose collar opening not circular. Probably most important. 4. Rotol thought their 'bullet ' design superior but I have not found reasons given. 5.Why would spinner be adapted from Spitfire when there was a specific Hurricane design?

Interesting read above. Some comments in reply: Dave Swindell – If I may say so, you provided a very good analysis. Further detail below but the RX5 hubs proper were identical. It is important to recognise the main constituent parts of the Rotol airscrew which I touched on this in my reply to G Boak’s post of 9/12 timed at 20.10 which did not attract any responses. I can’t be absolutely sure that there was a single common hub in the very early trials that commenced in 1939. However, I think it very likely and it would certainly have been the case by mid-year. Troy Smith - I have seen the Belgian aircraft previously but not in such a clear print. Thank you. The prop is clearly a Rotol magnesium type, developmental, or possibly even a Spitfire type although it’s impossible to say for certain. Apart from the side photo of G-AFKX that is the only photo I have seen of a Hurricane with magnesium bladed prop. Geoffrey – The contract cards are extremely useful in adding detail and specific dates to the timeline for the production props. I believe it is safe to say that contracts for the airscrews would have been for specific Hurricane designs, including spinners. Given the pressures on manufacturers (CSA) and the range of commitments to other spinner designs, the suggestion that there were stockpiled Spitfire spinners on hand for use (assuming they fitted) is unlikely. Nevertheless as this has been mentioned more than once, perhaps someone, somewhere, can shed some further light. Paul Lucas- a red herring I am afraid but there were two versions of the Fulmar prop/spinner combination. The first was an internal cylinder prop with shorter spinner. The later external cylinder type used a different version and different blades. Stevehnz- I believe the leaking oil was primarily an issue with DH props. What is latterly being touched upon are the technical aspects of what were complex pieces of machinery. This is probably where the answer lies. I have access to a 1940 manual. The Spitfire magnesium RX/1 has 108 individual named component parts, which on a rough estimate produces about 1000 pieces in total for each 3blade unit. This excludes the governors and spinners. This would be roughly the same for each RX Hurricane/Spitfire type during 1940.Broadly speaking; the props are identical save in certain important respects. Each prop type has a specific fine pitch angle related to the specific blade types employed. There is no interchangeability between Spitfire and Hurricane, nor incidentally between Spitfire magnesium and wood. This rather suggests there are differences and technical reasons why this is so. The manual gives a precise definition of the appropriate spinner for the magnesium prop. The same applies to Hurricane wood blade props and later Spitfire (II) wood blade prop. ES/4 magnesium Spitfire ES/5 wood Spitfire (Mk II) ES/6 wood Hurricane (later 1940 alternative or substitute ES/9) A study of the prop component parts would explain why. Here I refer particularly to the blade adapters and blades. The blade adapters at the base of each blade were of differing lengths dependent upon the blade type and drawing number and from this, aircraft type. I should also mention that the blade root diameter for the magnesium prop was different to those of the Hurricane (and Spitfire) wood props. Dave Swindell was on the right lines regarding the spinner sizes in that the back plate diameters are not hugely different between Spitfire and Hurricane, although there are other differences. The diameter differential changed with the later Hurricane ‘bullet’ CM/1 and ES/9 where it should be noted that the Hurricane RX props remained as existing and were not ‘shrunk.’ My own view is that the Spitfire/Hurricane Rotol prop spinner is a most unlikely proposition i.e. mythical rather than factual. On a final (repeat) note, the Spitfire nose end is effectively circular, unlike that of the Hurricane- (worthy of study).

That’s a fair observation (re documentation) although it’s also an easy excuse for the hard of learning. I can accept that documentation may not exist or even be lying in a file somewhere. However, if there is no documentation, on what basis is the proposition formed?

🤣 Thank you Pat. On a general philosophical note, I believe that this Country in particular and the whole Western World would be in a far better position if the general consensus and ‘experts’ was/were challenged on a continuous and searching basis. Regrettably, so many don't have the gumption. Hurricane Rotols not so important, but we may as well get it right while we can.

I may have a view, but pose a genuine question to which (against the basic rule) I do not have the answer. I haven’t said it’s a myth. But is there documentation? This is not trolling. If it is a challenging question, fine, but why should any one object? So far no-one has cited any reference. I welcome any that may be forthcoming. You ask, ‘if they were not Spitfire propellers (do you mean spinners or propellers?) what were they?’ In reply, the obvious answer is Hurricane spinners/props. What I would say is that the spinners were designed around the hubs and meant to fair with the particular aircraft. Some basics: · G-AFKX spinner/prop on side photo was experimental. · Spitfire Rotol trials went on for some months and various spinner shapes/prop combinations were used · Hurricane Rotol trials even less well documented but process appears shorter · Spitfire nose end is effectively circular, unlike Hurricane- (worthy of study) · Rotol hubs were not designed with the Spitfire in mind · Rotol hubs did not determine spinner size/shape (beyond a certain point) · Blade adapters and blades were the variable factors (apart from pitch settings) · Spinners designed to suit · Hurricane two-piece nose collar introduced in early 1939 and predated the finalisation of Rotol prop designs by some months · Two-piece collar follows single-piece contours save for c/s unit bulges · Hurricane Rotol service trials after June 1939.Not fitted on Hurricane production line until Feb/March 1940 at the earliest. · Hurricane L2026 with Merlin III tested with Rotol c/s prop around July/August 1939 · Boscombe Down tests on first (production?) Hurricane Rotol c/s airscrew Oct 1939 · Rotol ‘bullet’ spinner not designed until early 1940 (there was considerable tension between Rotol and CSA) and not in production until later that year · No photos (have I seen) of R.A.F. Rotol Hurricanes in France other than wood blades I return to my question. Were Spitfire Rotol spinners/props used on Hurricane I’s and if so is there any supporting documentation or (I will add) contemporary sources?

I asked a genuine question. Is the proposition based entirely upon opinion/assertion based on photographs or is there documentary evidence? What is oversize? How can you tell?

How can you tell? My question relates to documentation.

Thank you. I will put you down as a 'No'. But in response , I couldn't see any. This matter crops up on so many threads I thought it deserved a slot all of it's own.

That Spitfire (bulbous Rotol) spinners or ‘props’ were used on Hurricane Mk I’s appear to be generally accepted as a fact. Is anyone able to provide documented references to support this?