2753

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.

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. 

 

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.

And another looking towards the Transom.

 

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.