From Wikipedia
“Ejector exhausts
The Merlin consumed an enormous volume of air at full power (equivalent to the volume of a single-decker bus per minute), and with the exhaust gases exiting at 1,300 mph (2,100 km/h) it was realised that useful thrust could be gained simply by angling the gases backwards instead of venting sideways.
During tests, 70 pounds-force (310 N; 32 kgf) thrust at 300 mph (480 km/h), or roughly 70 horsepower (52 kW) was obtained which increased the level maximum speed of the Spitfire by 10 mph (16 km/h) to 360 mph (580 km/h).
The first versions of the ejector exhausts featured round outlets, while subsequent versions of the system used “fishtail” style outlets which marginally increased thrust and reduced exhaust glare for night flying.”
Does anyone know when during production, the “fishtail” outlets were introduced? Spitfire Mk1 P9374 has the round outlets as does EP120, BM597 has fishtails as does R6915. I have also seen P7350 with the 6 outlet exhausts. Most Hurricanes I have seen have the “fishtail” exhausts.Is this a case of people using the exhausts that are available rather than the most authentic exhausts? (I am presuming that P9374 is correct! as Andys book tells about having to manufacture new ones.) 😉
By: MerlinPete - 18th December 2012 at 21:08
I had bought this hoping it would assist me in moulding a set of fishtails but looks as if I need to make the round version.
I kniow this isn’t Spitfire any thoughts on the type it would be used on?
Avro Lincoln and dH Hornet
Pete
By: Robert Whitton - 18th December 2012 at 20:14
I had bought this hoping it would assist me in moulding a set of fishtails but looks as if I need to make the round version.
I kniow this isn’t Spitfire any thoughts on the type it would be used on?
By: Graham Boak - 18th December 2012 at 17:40
Mk.Vs with 6xside exhausts.
Osprey Spitfire Aces of North Africa and Italy (Thomas)
JK715 SN.A Mackie – Malta
MH558 GO.C Foskett – Cyprus
MMP Supermarine Spitfire Mk.V (Matusiak)
9943 ex-JK360 postwar Yugoslav
EP506 RF.G This is a UK-based LF Mk.VB, with another 6x nose seen behind. Matusiak states that this fit was typical for late-1943.
By: Robert Whitton - 18th December 2012 at 14:49
I dont suppose that current flying Spitfires need to have their machine guns heated! but I will need to investigate further. P9374 is flying with (parts of) its original engine a merlin III and a photo of P9373 shows it also with the triple round ejectors.
By: Graham Boak - 18th December 2012 at 14:20
On the Hurricane, it seems that the Mk.II had fishtails from the start, although I really should dig out photos to prove that. Mk.Is generally don’t. So we are looking at autumn 1940 for a change-over?
There is a photo (or more? 87 Sq) of a Hurricane with 6 a side, but this is linked to night fighter operations rather than superior power.
Photos do exist of Spitfire Mk.Vc(Trop) with 6 exhausts a side, so I suggest the Osprey Mk.V Aces booklet as a likely best place to look. SN Mackie’s fighter? (EDIT They are common on Seafires with the same low-rated engines.) Other Mk.V Trops appear to have had fishtail or tubular 3xexhausts – photos of the well-known PPH on Malta show both at different times
Circular exhausts are, I believe, seen on Spitfire Mk.XVIs and presumably late Mk.IXs, as well as Griffons. I don’t know when this started, but late.
By: Edgar Brooks - 18th December 2012 at 13:48
There’s nothing about a change of exhausts in the Spitfire modification ledger, which points towards the 6 x fishtails appearing with the 60-series Merlins, since the Mk.V needed “augmenter” heating tubes run through the triple ejectors, then via the engine compartment and the leading edges, to provide heat for the outer .303″ Brownings.
Provision was made to introduce “multi-ejector exhausts” on the V(Tropical) in January 1944, but I’ve never seen a photo of one (hint.)
The multi-ejector exhausts, with circular exits, were not introduced until June, 1946, and were only intended for Griffon-powered airframes.
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December 18, 2012 at 11:43 am