Need help with a Rotol propeller

Just as a follow-up, I decided to go with light blue for the prop labels, and happily a sheet of Techmod Spitfire stencil decals included a whole bunch of disks in pink and light blue with various markings. I used the ones with a “B” which looks rather like the ones in the photo of FY-V. I also reshaped the prop tips to a more rounded configuration as shown in the photo.

Thanks, everyone, for the discussion and information.
Pip

No, there were alloy bladed (four bladed) versions.

If my information is correct, some IXs with Merlin 61 engines had alloy bladed props, while others had wooden blades. IXs with Merlin 63 engines and beyond all had wooden blades. According to www.spitfires.ukf.net, EN349 (first flight 2/3/1943) was the first IX with a Merlin 63, while EN498 (FF 4/15/43) was the last one with a Merlin 61. As one can see, there was a period of two months or so when IXs were being produced with both engines. The change-over to wooden bladed props must have happened during that time, at the latest, if not earlier.

There is no trace of any disc ever having been on our alloy blade.

Some lettering and numbers at the root still clearly visible above the collar. No disc, though. I am as certain as I can be that there never was.

So, that gives me an escape route if I can’t make up my mind what the proper disk color should be. Thanks!

No, there were alloy bladed (four bladed) versions.

I was always under the impression all four bladed hubs used wooden blades to help dampen the harmonics of the higher power Merlins..Meh but what do I know 😉

R5/4F5/4 props were also used with the Merlin 61 but in this case I would say you are correct in thinking that the aircraft in question is fitted with Dural blades which brings me onto the question of colour. The only actual answer I have is…I don’t know.

I doubt it’s yellow as that is well established as the colour for Waybridge blades at the time of the picture.

White? Well at some point in 1944 it is adopted for Dural blades, could it have been used before that date?

One possibility which I have no real evidence for is light blue. This is listed in 1944 as being in use to identify hollow steel Curtiss blades (remembering that Rotol electric props were licence built Curtiss designs). Could it be that it was originally used to identify any metal Rotol blade?

Anne

Ooh, blue! That could be neat! I agree that yellow is unlikely since it seems to have been used consistently for spruce/fir construction, and white in 1942 was being used for Jablo wood. If blue, looks like a very pale shade. Bottom line, whatever I choose, it’ll be hard to prove me wrong. Thanks again for the help.

Pip

There is no trace of any disc ever having been on our alloy blade.

Some lettering and numbers at the root still clearly visible above the collar. No disc, though. I am as certain as I can be that there never was.

R5/4F5/4 props were also used with the Merlin 61 but in this case I would say you are correct in thinking that the aircraft in question is fitted with Dural blades which brings me onto the question of colour. The only actual answer I have is…I don’t know.

I doubt it’s yellow as that is well established as the colour for Waybridge blades at the time of the picture.

White? Well at some point in 1944 it is adopted for Dural blades, could it have been used before that date?

One possibility which I have no real evidence for is light blue. This is listed in 1944 as being in use to identify hollow steel Curtiss blades (remembering that Rotol electric props were licence built Curtiss designs). Could it be that it was originally used to identify any metal Rotol blade?

Anne

What markings were used, or if any markings were used at all, on Dural blades pre 1944 appears to be one of the great unanswered of Rotol propellers and I’m sorry to say I don’t have the answer.

Could it be that the props shown in the photos on the ever wonderful Britmodller are not of R3/4F5/2 propellers with Dural blades but R5/4F5/4 props with RA 10046RTS Jablo blades? In 1943 these would have a white disks.

Tony T’s images are of Hoffman blades (checked by Dowty Rotol) which use a similar marking system but are not representative of the markings used during the war.

Anne

Hi Anne. Thanks for the response.

Is there any particular reason to suppose that the props are NOT R3/4F5/2’s? According to “Spitfire: the History,” that was the specified prop for Merlin 61s, plus the shape of the prop tips is clearly unlike the typical Jablo blades (see pic in post above).

I agree that the pictures Tony T posted do not reflect wartime markings.

Pip

The shot of the MK VII in the Britmodeller post is of EN474 in the US.

I photographed this machine prior to restoration in 1972 and subsequent installation in the Smithsonian.

It has a dull red disc and is not a dural (aluminium alloy) blade.

Mark

The photo I’m talking about shows BS451, a Mk. IX of 611 Sqn.:

The disks are clearly a similar color to the spinner and/or the prop tips.

The shot of the MK VII in the Britmodeller post is of EN474 in the US.

I photographed this machine prior to restoration in 1972 and subsequent installation in the Smithsonian.

It has a dull red disc and is not a dural (aluminium alloy) blade.

Mark

What markings were used, or if any markings were used at all, on Dural blades pre 1944 appears to be one of the great unanswered of Rotol propellers and I’m sorry to say I don’t have the answer.

Could it be that the props shown in the photos on the ever wonderful Britmodller are not of R3/4F5/2 propellers with Dural blades but R5/4F5/4 props with RA 10046RTS Jablo blades? In 1943 these would have a white disks.

Tony T’s images are of Hoffman blades (checked by Dowty Rotol) which use a similar marking system but are not representative of the markings used during the war.

Anne

I have seen magnesium blades (or evidence thereof!) on earlier Spitfires (eg IIa) but not sure if they carried these on to later mark Spits.

Have just checked out metal blade we have. It has no disc – yellow or white!

Bummer! The photo I’ve seen shows small, light-colored disks just outside the spinner (closer to it than the typical placement on wooden blades). I’ve read that white became the indicator for Dural blades, but it was used earlier on Jablo wooden blades with Rotoloid covering before the change-over to pink for all Jablo wooden blades. Yellow seems to have Rotol’s designator for spruce construction, but could they also have used it for Dural as well?

In any case, thanks for checking.
Pip

I have seen magnesium blades (or evidence thereof!) on earlier Spitfires (eg IIa) but not sure if they carried these on to later mark Spits.

Have just checked out metal blade we have. It has no disc – yellow or white!

Rotol blades

There was the “option” of magnesium alloy blades on a Rotol hub.

I’m not entirely certain but I believe some Whitley aircraft had them.

That would be a different colour spot in that case then?

Anon.

I hope to know this evening!

Not sure if Tony T’s images are the wooden Jablo finsh blades, though, or dural? Presumably the former?

I honestly cannot recall, but will ask my colleague who has it in his workshop.

I think the discs are still there, and seem to think they were yellow. The aircraft in question was lost in 1943.

An odd feature of this blade is that the tips were red and yellow instead of just the four inch yellow tip – but I suspect just a ‘one off’.

That’d be great, Andy, thanks! I can hold off on the prop for a week or so, and I’ll go with yellow in the absence of any further information.

Pip

I took these on the Mk19

http://www.britmodeller.com/forums/index.php?showtopic=50088

Hi Tony.
Yes, I saw those over at britmodeller. They’re lovely pics, even with your mug, but they’re also postwar markings. I don’t believe the Rotol logo appeared during the war.

Pip

I took these on the Mk19

http://www.britmodeller.com/forums/index.php?showtopic=50088

I honestly cannot recall, but will ask my colleague who has it in his workshop.

I think the discs are still there, and seem to think they were yellow. The aircraft in question was lost in 1943.

An odd feature of this blade is that the tips were red and yellow instead of just the four inch yellow tip – but I suspect just a ‘one off’.