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d-zine View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote d-zine Quote  Post ReplyReply Direct Link To This Post Posted: 06 February 2007 at 1:49pm
Hi,

These two photographs were scanned from articles passed on by Christian and show 2753 as she was at the builders yard prior to commisioning.


Starboard Bow.




Rear Deck Showing flush engine cover and rear facing engine room hatch.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote d-zine Quote  Post ReplyReply Direct Link To This Post Posted: 09 February 2007 at 4:59pm
Hi,

For comparison we have photographs of 2753's Wheelhouse when she was commissioned and again as she is know.

I suppose the main difference is the change from three engines to two engines.


Circa 1956



Circa 2006'ish




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Post Options Post Options   Thanks (0) Thanks(0)   Quote Christian Quote  Post ReplyReply Direct Link To This Post Posted: 09 February 2007 at 5:36pm

Hi d-zine, just going through some photos and noticed Flywood's props seem to be right-hand whereas they had left-hand props in service. She ran Packards after the Griffons were removed, would this account for this? Perhaps Pioneer can enlighten us. 

 

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Pioneer Quote  Post ReplyReply Direct Link To This Post Posted: 09 February 2007 at 5:57pm

Not having been down an Engine Room of these beautiful craft I would not know whether the Vdrives were on all Engines. I do know that the Griffon had the same rotation as the Packard/Merlin so if there were 3 V drives then the Props would all be Right Handed as per the Gay class.

(Ithink!!!)

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Post Options Post Options   Thanks (0) Thanks(0)   Quote d-zine Quote  Post ReplyReply Direct Link To This Post Posted: 09 February 2007 at 8:39pm

Christian and Pioneer,

The following extract from http://www.spitfiresociety.demon.co.uk  confirms that the Merlin and the Griffon did infact rotate in opposite direction. My stepfather flew Spitfires with Merlin engines and I recall that he said the plane would pull to the right on takeoff which would suggest that the engine rotated clockwise when viewed from the cockpit. Interestingly it would appear that the Griffon was changed to rotate in the same direction as the Napier aero engine so does that mean that the original Napier Sealions rotated the opposite direction to Flywood's current prop set up as well?

The first Griffon was built in 1934, and was effectively a derated engine of "R"-type, as was used in the Schneider- Trophy winning Supermarine S6 aircraft. As such it was a V12 liquid-cooled engine of 37 litres swept volume. Much of the design philosophy for the Griffon was to keep the overall dimensions close to those of the Merlins, to allow interchangeability. It is unfortunate that this engine was never developed to the degree that the Merlin was, and never exceeded it in overall power development. The major differences for the pilot was a less-smoothly running engine and one that rotated the propellor the opposite way to the Merlin. The standard anti- torque actions applied at takeoff power also needed to be the opposite way round to prevent a rapid departure off the side of the runway! This resulted from a decision by a committee of The Society of British Aircraft Constructors to aim for a "universal powerplant". The rationale was that any aircraft with a powerplant of around 2000HP should be able to have virtually any available comparable engine replaced should the original fail. Consequently direction of rotation of the Griffon had to change to match the engines of Bristol, Napier and Armstrong-Siddley (the Merlin, which was in widespread use at that time, especially by the USA- whose aero engines all turned the same way as the Merlin- stayed as it was). The cylinder firing order was changed to produce less resonance in the crankshaft and reduce the risk of failure. By June 1940 the Griffon II was rated at 1720HP with 1495HP at 14 500 feet. The First Griffon-powered production Spitfires were the Mk XII with a 1815HP Griffon VI. All Griffons had a Coffman cartridge starter.

So now the Questions:

  1. What size props are currently fitted to 2753?
  2. Where do they come from?
  3. Are the V-Drives just that and not subject to direction of rotation or are they proper gearboxes matched to the direction of rotation.
  4. When was 2753 re engined and by whom?
  5. Was she re engined with Merlins or were they the Packard V12's that predate the Packard Merlins?

I would be interested in finding out more about her post service history in particular her smuggling. When last in Gibraltar I spoke with a Royal Navy officer who quite clearly remembers her from the early to mid 1970's.

Christian, I don't know whether you would be able to check but any identifying marks on the Props and Gearboxes would be very useful in sizing for the engines and or replacement gearboxes.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote d-zine Quote  Post ReplyReply Direct Link To This Post Posted: 09 February 2007 at 8:59pm

Hi,

Photographs of the Rolls Royce Sea Griffon installation on a MkII Rttl.

I cannot remember where the images came from but they could be

from 2756 when stationed at Ghan.

 

 

 

 



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Post Options Post Options   Thanks (0) Thanks(0)   Quote d-zine Quote  Post ReplyReply Direct Link To This Post Posted: 09 February 2007 at 9:03pm

And another looking towards the Transom.

 

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Pioneer Quote  Post ReplyReply Direct Link To This Post Posted: 09 February 2007 at 10:09pm

Hello d-zine

I do stand corrected re the Rotation - I was basing my assumption on reading the original script of Saro News - the in house magazine of Messrs Saunders Roe - it was an article on the early Bras-d'or of the RCN - in that it stated that it was powered by 2 'handed' Sea Griffons from that I assumed (quite wrongly it seems) that they were mated through gearing only. Thank you for putting me right

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Christian Quote  Post ReplyReply Direct Link To This Post Posted: 09 February 2007 at 10:12pm

Hi d-zine

Your pics are from Servicepals, this is the third in the series;

Referring to your post elsewhere, you mention there were 21 of the Vosper design RTTLs, I make it 20- are you perhaps counting 2762E and 2772/2772E as different boats? Bear in mind she was re-numbered after her conversion from all aluminium to composite as one of the Krogerwerft D-Boats was numbered 2762. I think all the surviving boats are mentioned on this forum (2748,51,53,57,58,68,70 and 71). I'll check the props for markings when I'm next up the mole.

B Rgds,

Christian.  

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Post Options Post Options   Thanks (0) Thanks(0)   Quote d-zine Quote  Post ReplyReply Direct Link To This Post Posted: 09 February 2007 at 11:33pm

Hi Christian,

I was basing it on the following production:

  • MK Ia's  -2747,2748,2749,2750
  • MK I b's -2751,2752,2753,2754,2755
  • MK II's   -2756,2757,2758,2759,2760,2761,2762E
  • MKII's    -2767,2768,2769,2770,2771,2772E

BOLD INDICATES KNOWN/SUSPECTED SURVIVORS

I make this 21 units although for a while I thought it was 22 because I thought 2762E and 2772E were different boats.

Is there anyway of confirming the condition and location of 2768 and 2770.

Any information would be welcome.

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