Early low wing Fairey Barracuda

[nova10]

Greetings and salutations my friends.
A friend told me the original plans for what became the Fairey Barracuda depicted an aircraft with a low wing similar to the Battle and Fulmar. This was before the suits demanded a shoulder high wing and the design was changed.
Is this true or is my friend merely confusing the wing with the tail which was raised in height after initial test flights? If it is true does anyone have any pictures or diagrams?
Nova

 

[Stargazer]

No pictures, but confirmation that this was a real project. However, the shoulder wing was on the initial project, designated Fairey Type 100:

The prototype contract for the Fairey project was placed on 30th January 1939 and in February a production order for 300 examples was agreed. A Ministry document noted that the Exe had to be discarded but it was over two and a half months before it was finally decided to fit the Rolls-Royce Merlin. Replacing the Exe was a 1,250bhp (932kW) Merlin 30 which forced Marcel Lobelle, Fairey's chief designer, to redesign the aircraft. His answer was a low-wing type with the rest of the airframe not dissimilar to the final shape. Fairey also wished to use its own and far more powerful P.24 engine but the Merlin stayed.
In due course, to ensure that the requirements were met in full and to satisfy the CofG, the wing was pushed up to the shoulder position. Fitted with the low wing, and loaded with all of its equipment, the aeroplane would have fallen outside its safe operating envelope, so if the low wing was to be retained its leading edge would have to be moved forward and this would affect some of the pilot's view. Also the wing had to be foldable with the undercarriage fully retractable (on the Swordfish and Albacore the latter was fixed) and, to quote Bill Harrison in his Fairey Barracuda Warpaint 'Lobelle's design was, to say the least, quite brilliant in that he managed to incorporate the Ministry's requirements into an aeroplane overweight and underpowered'. The Barracuda was also fitted with large Fairey-Youngman flaps which, apart from their usual function, could be set at a negative angle of 30° to serve as dive brakes. The first prototype became airborne on 7th December 1940 and the type was eventually named Barracuda.

Source: British Secret Projects - Fighters and Bombers 1935-1950 (Midland Publishing)

 

[EwenS]

I don’t have the British Secret Projects book referred to but I do have Matthew Willis’ The Fairey Barracuda published in 2016. He has reference to a Fairey private venture design submitted to the Admiralty in 1937 with a low wing, twin engined layout (no drawings however). It was rejected as “unsuitable” but spurred the spec that led to the Barracuda.

He goes on to note in respect of the Fairey submission for this new spec, the Type 100, “It was a clean-sheet design, with little similarity to the firm’s previous Battle and P.4/34 land based light bombers.” It already had the shoulder wing as it was the only way of meeting the spec for the observer’s visibility. The other submission that reached prototype, the Supermarine Type 322, followed the same layout.

So do we have one or two designs leading up to the Barracuda. Ultimately it makes no difference as a low wing could never meet the spec.

What I’ve never understood is how the Barracuda could ever have been a better aircraft if fitted with the Exe/Boreas engine, even if it was supposed to be “very low drag”. It was only rated at 1150hp. The Merlin 30 with 1300hp was deemed inadequate and it was deemed underpowered with the Merlin 32 rated at 1640hp. Weight was part of the problem (an increase of 150-500lb by changing depending on who you believe - RR or Fairey) and drag from the radiators, but even so I have my doubts.

 

[Hood]

What I’ve never understood is how the Barracuda could ever have been a better aircraft if fitted with the Exe/Boreas engine, even if it was supposed to be “very low drag”. It was only rated at 1150hp. The Merlin 30 with 1300hp was deemed inadequate and it was deemed underpowered with the Merlin 32 rated at 1640hp. Weight was part of the problem (an increase of 150-500lb by changing depending on who you believe - RR or Fairey) and drag from the radiators, but even so I have my doubts.

I have had suspicions on these lines from time to time too. Even fitting the Griffon in the Mk.V didn't iron out the problems. Its too easy to hand wave with the Exe/Boreas as it was never built, we don't know much other than it seemed to run ok during testing. My gut feeling is that cooling flow would have been a problem, air-cooled inlines have never been easy in this regard and with 24-cylinders it would have been ambitious.

 

[EwenS]

Some more information on the Exe/Boreas here.

Rolls-Royce Exe (Boreas) and Pennine Aircraft Engines

From the late 1930s to the mid-1940s, Rolls-Royce developed two air-cooled X-24 aircraft engines: the 1,200 hp (895 kW) Exe and the 2,800 hp (2,088 kW) Pennine. Neither engine entered production.

oldmachinepress.com

Cooling doesn't seem to have been an issue given the large intake fitted to the Battle test bed. Oil consumption was. Plans were to increase power output to 1500hp. Bit better for a Barracuda but would it have been enough?. How long would it have taken to get there if development had been allowed to go ahead? 30% increase in power? It took 2-3 years to get the Merlin from 1030hp in Merlin I & II form in 1937, to 1275hp in Merlin VIII form and 1390hp in Merlin XX form in 1939/40 with RR prioritising it.

 

[Hood]

Cooling doesn't seem to have been an issue given the large intake fitted to the Battle test bed. Oil consumption was. Plans were to increase power output to 1500hp. Bit better for a Barracuda but would it have been enough?. How long would it have taken to get there if development had been allowed to go ahead? 30% increase in power? It took 2-3 years to get the Merlin from 1030hp in Merlin I & II form in 1937, to 1275hp in Merlin VIII form and 1390hp in Merlin XX form in 1939/40 with RR prioritising it.

True but it was only a test installation. There seems to have been nothing wrong with the Exe and certainly no show stoppers, high oil consumption could have been dealt with ok in service I should think.

The small size might have been a drawback later. Its 22 Litre displacement matched that of the Peregrine but the bore and stroke (~4in) were 1in smaller than all of the Kestrel family. Its compression ratio was high to compensate. 1,500hp might have been the upper limit of development for such a small cylinder. The Pennine with ~5in bore and stroke had a performance much more fitting for a 24-cylinder engine.

 

[tallguy]

Cooling doesn't seem to have been an issue given the large intake fitted to the Battle test bed. Oil consumption was. Plans were to increase power output to 1500hp. Bit better for a Barracuda but would it have been enough?. How long would it have taken to get there if development had been allowed to go ahead? 30% increase in power? It took 2-3 years to get the Merlin from 1030hp in Merlin I & II form in 1937, to 1275hp in Merlin VIII form and 1390hp in Merlin XX form in 1939/40 with RR prioritising it.

True but it was only a test installation. There seems to have been nothing wrong with the Exe and certainly no show stoppers, high oil consumption could have been dealt with ok in service I should think.

The small size might have been a drawback later. Its 22 Litre displacement matched that of the Peregrine but the bore and stroke (~4in) were 1in smaller than all of the Kestrel family. Its compression ratio was high to compensate. 1,500hp might have been the upper limit of development for such a small cylinder. The Peregrine with ~5in bore and stroke had a performance much more fitting for a 24-cylinder engine.

I've often wondered why Packards 5A-2500 never went into production. It seems a good solution for the 'cuda, as well as the Avro Manchester and possibly give the Battle a new lease on life.

 

[EwenS]

Cooling doesn't seem to have been an issue given the large intake fitted to the Battle test bed. Oil consumption was. Plans were to increase power output to 1500hp. Bit better for a Barracuda but would it have been enough?. How long would it have taken to get there if development had been allowed to go ahead? 30% increase in power? It took 2-3 years to get the Merlin from 1030hp in Merlin I & II form in 1937, to 1275hp in Merlin VIII form and 1390hp in Merlin XX form in 1939/40 with RR prioritising it.

True but it was only a test installation. There seems to have been nothing wrong with the Exe and certainly no show stoppers, high oil consumption could have been dealt with ok in service I should think.

The small size might have been a drawback later. Its 22 Litre displacement matched that of the Peregrine but the bore and stroke (~4in) were 1in smaller than all of the Kestrel family. Its compression ratio was high to compensate. 1,500hp might have been the upper limit of development for such a small cylinder. The Peregrine with ~5in bore and stroke had a performance much more fitting for a 24-cylinder engine.

Peregrine was a 12 cylinder 21ltr 880hp engine, and represented "the ultimate development of the Kestrel" using early experience with the Merlin using the same bore & stroke. So probably little development life left in it. The next development from it was the Vulture, basically 2 Peregrines on a single crankshaft and look how that worked out.

The 22ltr Exe was developed into the 2740hp, 46ltr Pennine later in the war.

 

[Schneiderman]

Exe came along just as the AM were pushing to rationalise engine production to concentrate on relatively small number of types. Exe offered nothing special in terms of performance and was an obvious one to cull.

 

[Hood]

The 22ltr Exe was developed into the 2740hp, 46ltr Pennine later in the war.

Just realised that I had a typo in my last line, should have read "the Pennine with ~5in bore and stroke had a performance much more fitting for a 24-cylinder engine."

I am no piston engine expert (and perhaps we are straying away from the topic in hand), but I assume the Exe had a such a small cylinder to ease problems with the sleeve-valve system and to ease the cooling?
In terms of power to displacement it was very powerful, in terms of power to its weight it was the same as the early Merlins (0.33lb/hp) and the power output was firmly in the V-12 bracket. So having 24 small cylinders was relatively inefficient. The Pennine was a much more practical proposition in terms of power output for its size, they should probably have pursued it over the Eagle.

It seems they did try a water-cooled Exe on the test stand but it never flew in the Battle.

 

[Nick Sumner]

Not to be picky but the Pennine was 5.4 in bore and 5.08 in stroke. A short stroke means higher piston speed is more easily attainable without piston ring flutter or disintegration of the rings. Junkers had a Jumo 213 model that had a piston speed of 17 m/s using very thin chrome plated cylinder rings. At the designed Penine engine speed (3500 RPM) the Pennine had a piston speed of less than 16 m/s. RR's favourite way to increase power was boost but they also made incremental advances in piston speed. The Pennine was comparatively lightly boosted to 12 lbs. later Merlins used 25 or even 28 lbs of boost

 

[Grey Havoc]

On a tangent:

https://www.warhistoryonline.com/news/fairey-barracuda-rebuild.html