Spitfire engine question.

[clicker]

I was having a chat with a friend of mine at Munich while waiting 4 hours for our flight and at one point we spoke about the Spitfire.

One question came up which I've not found an answer for in the "Spitfire, The history" by Eric Morgan and Edward Shacklady.

Was there any reason for the Merlin and the Griffon engine turning the props in the opposite direction to the other make and did that bring any problems in service, for example trimming the rudder for take off for a Merlin while flying a Griffon engined aircraft.

We decided it was just the way it was, but not 100 percent certain.

By the way the book does remark they had lots of info about the engines but the book didnt have the room for it, shame.

Thanks Ron

[clicker]

Oh and we also decided the earlier versions were the better looking ones, myself its the Mk V and Mk IX versions and I'm not keen on the teardrop cockpits.

[Chugalug2]

I refer the honourable gentleman to an answer given earlier, on the best thread, of the best forum on PPRuNe:-
http://www.pprune.org/military-aircr...-ww11-181.html

[Danny42C]

Which way round ?

clicker

I said a few words about this in #3602 p.181 on the "Pilot's Brevet in WW2" Thread. Think it just happened, but we really want an engineer's opinion (Geriaviator ?) You'd have to be a dumb bunny not to know which engine you were sitting behind - the ruddy great bang from the Coffman was a clue.

I think the cutaway fuselage looked nicer (and the longer nose, too). You can't please everbody !

Danny42C

[Fareastdriver]

You have to remember that the Griffon was not developed from the Merlin. It was a seperate design of its own.

[clicker]

Thanks Gents,

Much as I expected. We were aware they were separate engines thence the thought of "It just happened that way"

[bcgallacher]

I believe that the engines themselves both rotated clockwise (from the front) but the Merlin has a spur reduction gear which rotates the propeller in the opposite direction. The Griffon has an epicyclic reduction gear which rotates the propeller in the same direction as the engine. The Merlin propeller shaft is above the crankshaft centre line whilst the Griffon prop shaft is in line with the crankshaft - that is why the nose contour of Spitfires with Griffon engines is different from Merlin engined Spitfires.
European engines to this day rotate clockwise whilst American engines rotate a.c.w.- I do not think there is any reason for this except custom and practice.

[JonnyT1978]

My memory is a little hazy but I think the reason for the difference may be down to one/other/both of the following reasons:

a) The Merlin (originally the PV.12) was a development of the Kestrel, whereas RR went back to the 'R' engine from the Supermarine S6 (of Schneider Trophy fame). While the Merlin benefited greatly from a lot of the r&d that went into the Schneider Trophy program, it was not directly derived from the 'R', unlike the Griffon.

b) Wasn't there some committee set up before/during the war that decided that in future all prop-aero engines had to rotate the same way, for pilot training and ease of pilots being able to transfer between types (not to mention propeller manufacture)? And it just so happened that the Merlin did not rotate in the 'correct' direction, but given it's use in so many types it was allowed to continue....

[Brian Abraham]

Was there any reason for the Merlin and the Griffon engine turning the props in the opposite direction

Development of the Griffon began in 1939 at the request of the Fleet Air Arm, Navy aircraft tending to be larger and heavier than their land based counterparts, thus placing greater demands on engine power. In the late 30's the Society of British Aircraft Constructors established standardisation guidelines, which included the direction of propeller rotation, clockwise when viewed from the front. The Griffon was merely complying with the new standardisation rules.

[Milo Minderbinder]

existing thread worth reading

http://www.pprune.org/tech-log/45055...-rotation.html

[Abbey Road]

And there was me thinking that it was due to which hemisphere of the earth that particular Spitfire models were expected to be operated, so the engine/prop rotation was cancelled out by Coriolis force.

And if you believe that, you probably believe in Santa, the Tooth Fairy, the Easter Bunny and Tony Blair.

[Nimbus20]

Abbey Wood

That, posted yesterday, would have resulted in a satisfactory harvest for you!

[Fareastdriver]

European engines to this day rotate clockwise whilst American engines rotate a.c.w.- I do not think there is any reason for this except custom and practice.

American engines have the output, ie the propellor, on the business end of the engine in the same way as automobiles have the transmission. The result is that their engines are installed backwards in comparison to British engines. On the big Wright Cyclone or Pratt & Whitney twin row radials the rear bank by the firewall have the low number cylinders so the engine rotates clockwise looking from the rear.

[NutLoose]

Well unless they're on the likes of a Piper Seneca then both of the American Continental flat 6 engines rotate in different directions.

[brokenlink]

If my memory serves me correct are not the Merlins on a Mosquito "handed" to avoid "torque steer"?

[Fareastdriver]

No, that was the Hornet.

[aw ditor]

DH Hornet had handed' engines/props, (and so did a variant of the PA31). There is a theory that the R Engine in the Seaplanes rotated that way because of the take-off direction for the Schneider Trophy around the Isle of Wight (to the West?) and the torque dug-in the most appropriate float on take-off. Griffons developed from the R Engine so................... .

[Fareastdriver]

There is a theory that the R Engine in the Seaplanes rotated that way because of the take-off direction for the Schneider Trophy

In that case the Germans had a hand in it too because the DB601 rotated the same way.

[Bing]

I think with the Hornet it wasn't the engines that were handed, just the gearbox where an extra cog in one of the boxes reversed the rotation of the output shaft.

[dragartist]

A400M

The A400M clearly does not comply with the standard!
Down between props I think was the phrase I heard.

Suprised no one from the RR heritage trust has not been on with the answer.