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diameter of 4-blade propellor, Fairey Barracuda Mk. II?


ilj
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Does anyone know the diameter of the 4-bladed propellor of the Fairey Barracuda Mk. II?

 

I'm asking because the kit prop for the Special Hobby SH72306 production looks a little short-bladed to my eye and I am considering a correction.

 

thank you

 

ilj

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11ft 8.5ins for all Mk IIs and IIIs with the Merlin 32 engine.  11ft 9ins was the Mk I three-blade diameter for the Merlin 30 engine. This information is directly from the original Barracuda Air Publication leading particulars section.

Edited by Dervish
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I have some additional information from my files to augment Dervish’s replies above although there is a slight variance.

 

The 3 blade props used on the Merlin 30 powered aircraft (Barracuda 1 and 2) were of 11ft 9ins diameter. As has been stated the Merlin 32 4-blader was of 11ft 8.5ins (or according to a different schedule 8.3ins) diameter.

 

Interestingly, as far as my info goes, the blades on all three versions were DS940 types, also used on the Hurricane Mk2 (and possibly Mk4) and Defiant Mk2. My scale is not 1/72 but perhaps substitutes might be found in kits of these aircraft.

 

In any event, I have measurements for this blade which might be helpful to the OP.

 

Tip to top of blade adapter (the metal ring at the base of the wooden blade) - 4ft 11ins

Max chord -13.25 inches (measured on flat side)

 

(Note that the same Rotol blades could be used on propellers of differing diameters with the use of different blade adapters. To add grist to the mill, the 4 blade hub had an increased radius over the 3).

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2 hours ago, Dervish said:

Barracuda I had the Rotol RX5/12 propeller and the Barracuda IIs and IIIs had the Rotol R4/4B5/2 propeller.

Same diameter but different blade profiles? Don't know a whole lot about props- just curious!

Mike

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On 20/09/2021 at 09:23, Dervish said:

Barracuda I had the Rotol RX5/12 propeller and the Barracuda IIs and IIIs had the Rotol R4/4B5/2 propeller.

You are quite right, but for the sake of completeness one should I believe add the RX/5/II for the Mk1 and R4/4B5/8 for the Mk2.

 

As a general comment, to have the propeller type is always useful and I compile such detail. Interestingly, for de Havilland bracket propellers it seems the hub type and radius were specific and individual to a specified diameter and blade, although for Rotol types the position appears less clear cut.

 

However, from the modeller’s viewpoint it must inevitably be the blade (and spinner) that is generally the focus. It is also where model manufactures appear often fail in the accuracy stakes which is where the OP started.

To an extent I sympathise with kit manufacturers. In the main, they will probably rely upon some basic information, generic shapes and photos. The degree of accuracy will therefore be variable although, very often a little more research would pay dividends. Then again, is it worth the bother?  

 

The shape of DS(or DA)940 blade (or for that matter any other period blade) is quite a difficult thing to pin down from photos given the unique circumstances of each capture. I am reasonably certain this photo of R S Tuck and ‘Ginger’ Lacy in front of a Hurricane on the ‘Battle of Britain’ film set shows this particular blade to good effect (certain other Hurricane Rotol blades look quite similar and it can be difficult to differentiate). However, without knowing the correct diameter, exposed blade height, aerofoil shape and chord dimensions, creating a scale facsimile is almost impossible.

 

spacer.png

 

This particular blade was also used on several aircraft. On the Hurricane fitted with the DS940, the diameter is 11ft 3ins compared with the 11ft 9ins/11ft 8.5ins of the Barracuda and 11ft 9ins of the Defiant II. This illustrates my point regarding the differing Rotol propeller diameters using exactly the same blade.

 

The standard hub radius for the 3 blade Rotol is 6 inches, increasing to 8 inches for the 4 blader. This will account in some respect for the increased diameter in the case of the Mk II Barracuda. In the case of the 3 blade hub, together with the former, the principal difference will be through the use of different blade adapters.

 

The blade adapter can be seen in this photo of Hurricane P3175 at Hendon. This is the section attached to the bottom of the blade which inserts into the bearing housing which in turn inserts into the hub:

 

spacer.png

 

This is quite different to the dH/Hamilton Standard steel or dural blades which were adjusted for length/diameter principally through a process of ‘cropping’ or ‘cutting down’ from the tip of the master blade.

This is not say that Rotol did not have some basic blade shapes which were scaled up or down but I have seen no documentary evidence to that effect.

Edited by V Line
Edit R4/4B5/8 to correct typo.
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1 hour ago, V Line said:

You are quite right, but for the sake of completeness one should I believe add the RX/5/II for the Mk1 and RX/B5/8 for the Mk2.

 

As a general comment, to have the propeller type is always useful and I compile such detail. Interestingly, for de Havilland bracket propellers it seems the hub type and radius were specific and individual to a specified diameter and blade, although for Rotol types the position appears less clear cut.

 

However, from the modeller’s viewpoint it must inevitably be the blade (and spinner) that is generally the focus. It is also where model manufactures appear often fail in the accuracy stakes which is where the OP started.

To an extent I sympathise with kit manufacturers. In the main, they will probably rely upon some basic information, generic shapes and photos. The degree of accuracy will therefore be variable although, very often a little more research would pay dividends. Then again, is it worth the bother?  

 

The shape of DS(or DA)940 blade (or for that matter any other period blade) is quite a difficult thing to pin down from photos given the unique circumstances of each capture. I am reasonably certain this photo of R S Tuck and ‘Ginger’ Lacy in front of a Hurricane on the ‘Battle of Britain’ film set shows this particular blade to good effect (certain other Hurricane Rotol blades look quite similar and it can be difficult to differentiate). However, without knowing the correct diameter, exposed blade height, aerofoil shape and chord dimensions, creating a scale facsimile is almost impossible.

 

spacer.png

 

This particular blade was also used on several aircraft. On the Hurricane fitted with the DS940, the diameter is 11ft 3ins compared with the 11ft 9ins/11ft 8.5ins of the Barracuda and 11ft 9ins of the Defiant II. This illustrates my point regarding the differing Rotol propeller diameters using exactly the same blade.

 

The standard hub radius for the 3 blade Rotol is 6 inches, increasing to 8 inches for the 4 blader. This will account in some respect for the increased diameter in the case of the Mk II Barracuda. In the case of the 3 blade hub, together with the former, the principal difference will be through the use of different blade adapters.

 

The blade adapter can be seen in this photo of Hurricane P3175 at Hendon. This is the section attached to the bottom of the blade which inserts into the bearing housing which in turn inserts into the hub:

 

spacer.png

 

This is quite different to the dH/Hamilton Standard steel or dural blades which were adjusted for length/diameter principally through a process of ‘cropping’ or ‘cutting down’ from the tip of the master blade.

This is not say that Rotol did not have some basic blade shapes which were scaled up or down but I have seen no documentary evidence to that effect.

The AP for the Mk I and II doesn’t mention the RX/5/11 nor the RX/B5/8, just the same props as mentioned on the MkII and Mk III AP.

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The view from the Ministry of Aircraft Production. Propeller reports start in March 1942.

 

Barracuda Mark I production July 1942 to February 1943 (33 built, 23 Fairey, 4 Blackburn, 5 Westland, 1 Boulton Paul)
Barracuda Mark II production October 1942 to November 1945 (2,097 built, 1,107 Fairey, 696 Blackburn, 13 Westland, 281 Boulton Paul)
Barracuda Mark III production March 1944 to November 1945 (410 built by Boulton Paul)

Merlin 30 production from November 1940 to July 1942, (660 built at Derby)
Merlin 32 production from June 1942 to April 1945, (3,500 built at Derby)


To March to July 1942, propellers are Rotol Hydraulic 3 blade (50 made in the 5 months), for Barracuda March to June for Barracuda I in July.  First entry for Rotol Hydraulic 4 blade for Barracuda (no mark number) in July.

 

August 1942 Rotol Hydraulic 4 blade, Barracuda becomes Barracuda II

January 1943 report gives Rotol Hydraulic 4 blade, Barracuda II R4/4, B5/1, Constant Speed Unit Rotol Hydraulic, Barracuda I, II GR/5C.  The Hurricane is also Using the GR/5C as well as the GR/2C.

 

April 1943 Constant Speed Unit, Hurricane II, IV, Barracuda I, II GR/5C (no more 2C for the Hurricane)

June 1943 Constant Speed Unit, Hurricane II, IV, V, Barracuda I, II GR/5C

October 1943 Rotol Hydraulic 4 blade, Barracuda II, III R4/4, B5/1.  Rotol Hydraulic Constant Speed Unit presumably under "various" users of GRF and GR.  The CSU under repair table lists Fulmar, Hurricane II, Barracuda II, Defiant II, Beaufighter II, Spitfire VI, VII, VIII, IX, X, XI, Seafire III as having GR/5c or GR/8c CSU.  (The Spitfire II and V, Seafire IIc having GR/5b or GR/8b)

 

December 1943 Rotol Hydraulic 4 blade, Barracuda II, III R4/4B5/2

February 1944, no Barracuda entry in propeller production, back in March but as Barracuda, no mark information.

April 1944 Rotol Hydraulic 4 blade, Barracuda II, T.R.III R4/4B5/2

May 1944 Rotol Hydraulic Constant Speed Unit "various" now GRF and GR/GL

January 1945, last entry for Barracuda propeller production.

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10 hours ago, Geoffrey Sinclair said:

The view from the Ministry of Aircraft Production. Propeller reports start in March 1942.

 

Barracuda Mark I production July 1942 to February 1943 (33 built, 23 Fairey, 4 Blackburn, 5 Westland, 1 Boulton Paul)
Barracuda Mark II production October 1942 to November 1945 (2,097 built, 1,107 Fairey, 696 Blackburn, 13 Westland, 281 Boulton Paul)
Barracuda Mark III production March 1944 to November 1945 (410 built by Boulton Paul)

Merlin 30 production from November 1940 to July 1942, (660 built at Derby)
Merlin 32 production from June 1942 to April 1945, (3,500 built at Derby)


To March to July 1942, propellers are Rotol Hydraulic 3 blade (50 made in the 5 months), for Barracuda March to June for Barracuda I in July.  First entry for Rotol Hydraulic 4 blade for Barracuda (no mark number) in July.

 

August 1942 Rotol Hydraulic 4 blade, Barracuda becomes Barracuda II

January 1943 report gives Rotol Hydraulic 4 blade, Barracuda II R4/4, B5/1, Constant Speed Unit Rotol Hydraulic, Barracuda I, II GR/5C.  The Hurricane is also Using the GR/5C as well as the GR/2C.

 

April 1943 Constant Speed Unit, Hurricane II, IV, Barracuda I, II GR/5C (no more 2C for the Hurricane)

June 1943 Constant Speed Unit, Hurricane II, IV, V, Barracuda I, II GR/5C

October 1943 Rotol Hydraulic 4 blade, Barracuda II, III R4/4, B5/1.  Rotol Hydraulic Constant Speed Unit presumably under "various" users of GRF and GR.  The CSU under repair table lists Fulmar, Hurricane II, Barracuda II, Defiant II, Beaufighter II, Spitfire VI, VII, VIII, IX, X, XI, Seafire III as having GR/5c or GR/8c CSU.  (The Spitfire II and V, Seafire IIc having GR/5b or GR/8b)

 

December 1943 Rotol Hydraulic 4 blade, Barracuda II, III R4/4B5/2

February 1944, no Barracuda entry in propeller production, back in March but as Barracuda, no mark information.

April 1944 Rotol Hydraulic 4 blade, Barracuda II, T.R.III R4/4B5/2

May 1944 Rotol Hydraulic Constant Speed Unit "various" now GRF and GR/GL

January 1945, last entry for Barracuda propeller production.

As usual, very interesting information. You have added a further propeller type to the list in the R4/B5/1. Not included in Dervish’s copy of the AP, nor in my data.

 

As your stats have taken us into 1945, I can add, for the Barracuda Mk V:

 

Griffon VIII – R33/485/9 -12ft 6ins diameter- Weybridge blade

Griffon 37 – R47/465/1 -12ft 6ins diameter – Jablo blade

 

These would be of LH rotation.

 

The detail that I have shared is taken from Rotol schedules.

 

I had hoped to nudge the thread back in the direction of the actual blades, but there we go!

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2 hours ago, ilj said:

The Special Hobby 1/72 Fairey Barracuda kit looks pretty excellent, except for the propellor which looks undersized to me.  Is this just me?  Opinions?

 

https://www.specialhobby.info/2016/12/sh72306-fairey-barracuda-172-built-model.html

I took a look at the relevant sprue (?):

 

https://www.super-hobby.fr/products/Fairey-Barracuda-Mk.II.html#gallery_start

 

From this it strikes me that the shape doesn't look horrendous but trust the photo and dimensions above will assist you to match up to a DS 940 blade. 

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12 hours ago, ilj said:

The Special Hobby 1/72 Fairey Barracuda kit looks pretty excellent, except for the propellor which looks undersized to me.  Is this just me?  Opinions?

 

https://www.specialhobby.info/2016/12/sh72306-fairey-barracuda-172-built-model.html

I agree, it does look rather anemic in both diameter and chord.:frantic:

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I just got my mail package containing the SH 1/72 Barracuda and examining the plastic, it is apparent that the propellor is drastically undersized.

 

The diameter of the kits's 4-bladed prop, assembled on the hub with the spinner on, is 43.7 mm, which translated into 'actual size' is 10' 4"

 

43.7 x 72 = 3146.4 mm = 10.3228' = 10' 4"

 

The actual size of the prop is 11' 8.5", so the kit prop is scale 1' 4.5" too small (about 88% of correct size).

 

I can't see any way to fix this with the supplied plastic.

 

 

 

 

Edited by ilj
addition of calculations
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  • 1 month later...

To obtain a usable propellor for my SH model, I ordered and have received a 'Frog' origin 1/72 Fairey Barracuda kit.  The diameter of the Frog kits's 4-bladed prop (with some flash) is 51.5 mm, which translated into 'actual size' is 12' 2"

 

51.5 x 72 = 3708 mm = 12.1654' = 12' 2"

 

The actual size of the prop is 11' 8.5", so the kit prop is scale 5.5" too large (about 104% of correct size).

 

The diameter to aim for is 49.6 mm, a difference of -1.9 mm from the Frog prop - I think with the flash removed and a little careful sanding to adjust this to the characteristic Rotol sabre tipped shape I'll have a usable prop 🙂  image showing the two props

 

spacer.png

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