Full-radial engine FAA?

[Hurricane IIc]

Hello,
Interesting idea, as radials are supposed to be generally more damage-resistant than an inline; I like the idea of the Hawk 75, available early, for carrier use rather than the Wildcat/Martlet due to the Hawk's wider-track undercarriage and great climb. Perhaps the British Purchasing Commission set up early 1940 might have chosen this.
The other I really like, but am more skeptical about, is the Gloster F5.34. Great handling like the Hawk 75. At first with the Mercury temporarily, but later, heavier engines could prove to be too much for this lighter airframe I would think.
I am also skeptical about adding a heavier engine to the Skua; FAA test pilot Erich Brown said it was noseheavy already.
I would think though that at least in the first half of the war, it could be 2 planes powered by the same Merlin: Hurricane as a fighter + Fulmar as a bomber (Erich Brown stated that it was stressed for dive-bombing). I think the Defiant would be robust, but too heavy until mid-war more powerful engines could be fitted (due to take-off distance).
My argument for the radial would be that the Hurri/Defiant had that big ventral radiator that would catch on the water during ditching. If those could have been replaced with leading-edge radiators as done on the Whilrwind and Mosquito in 1940, then that would give increased lift and wing area as well, I would think - hopefully enough to aid the Defiant's take-off distance and possibly allow the Fulmar to carry a torpedo if there is enough clearance beneath with the radiator removed.
I could really see the Defiant developed mid-war perhaps with Merlin 27 or even Hercules VI, worthwhile I think because of it's modern construction (all-metal fuselage, so lower drag than the fabric Hurricane). The long fuselage was strongly built, so possibly could carry a large fuel supply where the turret used to be.
Well there's some ideas for a number of aircraft.
Thanks,
Gerry

 

[nuuumannn]

Bristol can also try and come out with another set-up, with at least one 'collective' exhaust pipe, so 7 cylinders share one pipe, so the losses are further lowered.

One thing Bristol could do is get rid of the exhaust collector ring altogether and make individual stacks a la Centaurus in the Sea Fury or in the manner of the Centaurus Tornado, although that installation underwent redesign.

 

[Shortround6]

Thanks for the overview.
The day fighter/bomber exhaust(s) do not need to be several feet long, like in the night bombers' installation (needed for the flame suppressor). Bristol can also try and come out with another set-up, with at least one 'collective' exhaust pipe, so 7 cylinders share one pipe, so the losses are further lowered.

How beneficial exhaust thrust is depends on the airplane itself and what roles you want it to fly. Low level and low speed doesn't allow exhaust thrust to do much unless you play some real games with the exhaust (exhaust thrust augmenters) . Low altitude means a higher atmospheric pressure at the exhaust pipe end (nozzle?) which affects the exhaust gas velocity. Thrust is NOT horsepower, the same thrust at different speeds results in different HP ratings. A Spitfire doing 300mph at low level will get more of a "boost" from the same exhaust thrust as a 228mph Barracuda.

The Barracuda's primary problem in the Pacific was the need to fly over Indonesian mountain ranges to strike at targets on the eastern side of Java, which necessitated a high-altitude performance which the Barracuda's low-altitude-rated Merlin 32 engine with single stage supercharger could not provide.

Now this assumes that the FAA, which specified the special, low altitude single speed Merlin used in the Barracuda, wouldn't also specify a special, low altitude single speed version of the Hercules ( as used in Coastal command Beaufighters and Wellingtons) and wind up with pretty much the same problem once the aircraft arrived in the Pacific. If the FAA had known they would be flying torpedo bombers over mountains they might have spec-ed/fitted 2 speed Merlin XX series engines and fixed the problem that way

Hercules VI and subsequent models (those with 13 in impeller) have had 2nd FTH at 15000 ft, making there 1500 HP an more (the Mk.XI preceded the Mk.VI). Plenty of HP will be saved via non-use of underslung radiators.
Hopefully, our (my?) new fighter will be much better performer than the Re.2000, that was sporting a 1000 HP radial and still making almost 330 mph. Without resorting in a tiny and/or 'trick' wing, and without any great shakes in streamlining of a radial engine and exhaust stacks layout.

FAA spec-ed special model Merlin's for low altitude work when similar performance could be had from 2 speed ( not even two stage) Merlins. What ever drag you are saving by getting rid of the radiators is lost due to the much higher drag of the radial engine installations. Please remember that even a mid 1942 P&W test hack (prototype) radial engined P-40 had 8% more drag than an early P-40.

Not sure you want to use the Re. 2000 as a Benchmark. It may have hit 330 mph but that is without self sealing tanks and armor and with light armament. Sources differ on weight but the series I aircraft might have weighed as little as 5610lbs loaded. For some reason changing the engine to a DB 601 or to a later 1175hp radial changed the speed very little (higher weights and drag from wing guns?)

Some Barracudas had some rather large exhaust shrouds, perhaps for night flying.

Some of these may have Griffon engines? But V-12s have got crappy exhaust placement for pilot trying to do a night landing on a carrier.

 

[nuuumannn]

Some of these may have Griffon engines? But V-12s have got crappy exhaust placement for pilot trying to do a night landing on a carrier.

Yep, Barracuda V had a Griffon. The aircraft in the pics is one of the V prototypes - the yellow P in a circle - essentially a Mk.III converted, and was put into production as an interim until the Spearfish entered service, for use in the Pacific. it was also fitted with radar for night attacks, hence the shrouded exhaust. The earlier Barras had the exhaust ducting placed so the gases would not cloud the big observer's window under the wing. Interestingly, that top picture, which shows a Barracuda II, not a Mk.I as the pic image states, has the pillars fiitted for carrying ASV radar on top of the wings, but the antennae are not fitted. I thought they might have been blotted out by the censor, but it doesn't appear so. Nice pics.

 

[yulzari]

As an aside on the Barracuda: the French bought 10 of them post war for use as clandestine STOL agent insertion and recovery aeroplanes into eastern europe. Much as the Lysander was used in WW2 in France. Serving 1948-54 IIRC.

 

[tomo pauk]

What about an earlier fighter (1938-41) designed around a smaller radial? Earliest choices are Mercury and Pegasus, followed by Perseus and Taurus. Each of them has some benefits and shortcomings.
Mercury has a single speed supercharger, that gave either good power at ~15000 ft, or at ~6000 ft (almost 900 HP) and for take off. Benefits: it is in wide scale production and use, light, not too bulky.
Pegasus is bulky (sorta like Wright Cyclone, that can be used as a replacement?), but it is still light, there is a two-speed variant available before 1940, power is between 900-1000 HP, depending on altitude and version.
Perseus is a bit like Mercury, just with sleeve valve technology, just a bit more power than Mercury. There was no two-speed supercharger?
Taurus is a twin row engine, with smaller cross section, going at 1300 lbs. No two speed S/C, so the choice must be made between low-alt and hi-alt versions. Either about 1100-1130 HP at 3500 ft, or 1000 HP at 15000 ft. Can be replaced by Twin Wasp. Problem was reliability, that took some time to solve. The production did not started before the outbreak of the war.

The resulting fighter should be of modest size, eg. wing of circa 200 sq ft? Similar to Gloster F.5/37, Italian early monoplanes, Ki-43, or maybe like CW-21, or P-66?

 

[Shortround6]

British were hamstrung by the engines, which as you noted were a bit on the low powered side. All but the Pegasus were 25 liter engines compared to the 30 liter American radials. Pegasus was 28.7 but had a few problems as far as development went.

The American fighters using 30 liter air cooled engines and American 100 octane fuel weren't exactly stellar performers once they porked up ( gained weight) with armor, bullet proof windscreens and self sealing tanks ( adding guns and ammo didn't help either).

Your list of fighters (Gloster F.5/37, Italian early monoplanes, Ki-43, CW-21, or P-66) all performed as well as they did, in part, due to a lack of armor,BP glass, self-sealing tanks and sometimes good armament.

The FAA could very well have built a fighter better than the Gladiator or Skua but trying to use it against shore based 109s at any time or Japanese Zeros in early 1942 would have shown it to be a strictly 2nd rate aircraft. Try thinking about early Brewster Buffalo which meets many of your criteria ( 208sq ft wing, 950-1100hp engine, a bit reduced armament compared to later models, lack of good protection).

 

[tomo pauk]

Agreed re. capability against Bf-109 and Zero. The 'modest' fighter should be indeed better than Gladiator and Skua, and about as good as Cyclone-powered Martlet/Wildcat, as well as Sea Hurricane* (Merlin III)? There FAA decks were not really awash with those two before mid 1942, let alone before that.
By late 1941/early 1942, we should have, hopefully, a far more capable fighter aboard. The 'legacy' designs might receive Taurus by then (bugs are out by that time?), or maybe Cyclone or Twin Wasp?

Wonder whether an equivalent of the Nakajima Kate should be available to the FAA in 1st half of the ww2, using the technology of time (instead of Albacore); ditto for a fully fledged dive bomber?

*the Merlin III in Sea Hurricane was allowed for plenty of boost at lower altitudes, so it would be a tough task to match that with low-boost Bristol, even given a smallish airframe?

 

[Shortround6]

The small fighter would be "iffy" compared to the Cyclone-powered Martlet/Wildcat as you have to keep the weight down, not only for performance but for landing /taking off. Wildcats fixed wing was only about 900lbs in weight? about 3.5lbs per sq ft? cutting back to 200 sq ft only saves about 200-210lbs. If you want the same wing loading you have to cut the gross weight of the fighter from around 7300lbs to 5600lbs. Lighter engine helps but you need lighter armament (not hard with the four .50s and ammo) less fuel, lighter fuselage and so on.

remember that your primary goal is not so much fighter vs fighter combat but stopping the bombers from reaching the carrier/fleet units. Go too light on armament and you can't do the job. British carriers were, for the most part, rather restricted in numbers of aircraft carried so there will be only small numbers of fighters airborne at any one time, breaking off combat and landing due to low ammo might not be good. You need enough ammo and fuel for multiple interceptions.

Skua wasn't a bad Dive bomber, there is just no engine to go to for the MK II and MK III

Val started with a 710hp Nine Cylinder and switched to an 840hp 14 for prototype trials, first production version went to 1000-1070hp but the 1300 hp engine doesn't begin to show up until the middle of 1942 (after all the initial action is over).
The Dauntless didn't get 1200hp until the -5 version.

Even IF you build a 9 cylinder version of a 1600hp Hercules you wind up with 1028hp which is way too little at that point. Sticking a Pegasus on it and accepting the decrease in forward vision is the best you can do for a British radial.

Torpedo bomber is going to follow a similar pattern. Any plane capable of performing a combat mission using a 800-1000hp engine is going to be too lightly built to take a 1300-1600hp engine later on.

 

[tomo pauk]

The small fighter would be "iffy" compared to the Cyclone-powered Martlet/Wildcat as you have to keep the weight down, not only for performance but for landing /taking off. Wildcats fixed wing was only about 900lbs in weight? about 3.5lbs per sq ft? cutting back to 200 sq ft only saves about 200-210lbs. If you want the same wing loading you have to cut the gross weight of the fighter from around 7300lbs to 5600lbs. Lighter engine helps but you need lighter armament (not hard with the four .50s and ammo) less fuel, lighter fuselage and so on.

The engine should be lighter by some 300-500 lbs, 200 lbs for smaller wings (they can be lighter per sq ft, because we will install lighter armament?), 200-250 lbs for lighter guns and ammo (8 LMG battery), lighter U/C (70-80 lbs?), 20 gals fuel less in a smaller fuel tank (130-140 lbs?), lighter fuselage (100 lbs?). Not quite a 1700 lbs difference, but somewhere between 1000 and 1200. Should weight in-between the light and heavy variants of the F2A/Buffalo.

remember that your primary goal is not so much fighter vs fighter combat but stopping the bombers from reaching the carrier/fleet units. Go too light on armament and you can't do the job. British carriers were, for the most part, rather restricted in numbers of aircraft carried so there will be only small numbers of fighters airborne at any one time, breaking off combat and landing due to low ammo might not be good. You need enough ammo and fuel for multiple interceptions.

Agreed all the way. The fighter should be carrying at least 8 LMG and 350 rpg.

Skua wasn't a bad Dive bomber, there is just no engine to go to for the MK II and MK III

Val started with a 710hp Nine Cylinder and switched to an 840hp 14 for prototype trials, first production version went to 1000-1070hp but the 1300 hp engine doesn't begin to show up until the middle of 1942 (after all the initial action is over).
The Dauntless didn't get 1200hp until the -5 version.

Even IF you build a 9 cylinder version of a 1600hp Hercules you wind up with 1028hp which is way too little at that point. Sticking a Pegasus on it and accepting the decrease in forward vision is the best you can do for a British radial.

Yep, agreed on Pegasus.

Torpedo bomber is going to follow a similar pattern. Any plane capable of performing a combat mission using a 800-1000hp engine is going to be too lightly built to take a 1300-1600hp engine later on.

A monoplane, retractable U/C, with Taurus? I know that it have it's share of problems, but maybe install it on something of size and shape of Fairey Battle? Alternatively, Pegasus on a tad a smaller airframe? Or, stick with Swordfish until a Hercules-powered bomber is available?

 

[nuuumannn]

British were hamstrung by the engines, which as you noted were a bit on the low powered side.

This is why the Brits placed much dolla in the in-line engines. The FAA British built replacements for almost all its ship based round engined aeroplanes were in-line engined. The Swordfish, of course was replaced by the Albacore, an improvement, but still a throw back, and even then the Swordfish outlived it on British carriers, but the Barracuda was intended on also being a torpedo carrier as well as a replacement for the Skua, but it never carried torpedoes into action. The torpedo carrier replacement on British carrers was the round engined Avenger. The Sea Gladiator fighter was replaced by more modern equipment such as the Sea Hurri and Spitfire, but these were intended as interims until something better came along, but in the end, it was US round engined aircraft that fulfilled that requirement. The FAA never incumbered itself with such a restriction as stating that its aircraft shouldn't have anything but round engines, which meant that it received some excellent in-line engined naval aircraft, such as later models of the Seafire and the Fairey Firefly attack aircraft.

 

[Shortround6]

Good weight breakdown of the F4F-3 is here: http://www.wwiiaircraftperformance.org/f4f/f4f-3-detail-specification.pdf

Weight of eight .303s with 350rpg is 439lbs, weight of four .50s as given for the "light" F4F-3 includes 200rpg. Weight of wings is more a function of not wanting them to break or bend while pulling high "G"s than weight of gun mounts and ammo boxes. Weight of an FM-2 wing was only about 30lbs lighter than F4F-4 wing. Adding the wing fold increased weight as did (perhaps) beefing up for higher gross weights?

While the F4F-3 engine is by far the heaviest it is also the most flexible and offers around 20% more power than the Mercury at many altitudes.

Fairy Battle was a bit under-powered with the Merlin III, switching from a a 27 liter liquid cooled engine to a 25 liter air cooled one isn't going to do a whole lot.

The thing to remember about trying to adapt existing land planes ( or land plane look alikes) is that the majority of pre war British carriers had rather restricted lifts and hanger space.

Picture may be of an escort carrier but illustrates the problem.

Lots of nice British carrier pictures in this photo stream: https://www.flickr.com/photos/39411748@N06/6330213580/in/photostream/

 

[ohogain]

Australia started to develop an air industry in the 1930's under the foresight of Lawrence Wacket. They produced Pratt Whitney R-1830 Twin Wasp hear in auburn where I work (now full of Mosques and Fast Food Burger Joints). Wacket, an engineering hero of Australia had tried to develop an aviation industry in Australia, however in 1931 his RAAF experimental station was shutdown under pressure from British manufacturers due to protectionist sentiment. Wackett was latter back in 1936 and lead the development of aviation in Australia using American designs such as the NAA-16 trainer and Australia developed a fairly effective fighter, the CAC Boomerang built around the R1830. Like All Australian designs of the era it featured impressive range.

The final nail in the coffin for use of anything British in terms of engines was when Britain reneged on allowing license production of its water cooled fighter engines. When Darwin was bombed by the Japanese it was lucky American P-40 on a staging mission were able to provide some protection.

From then on, also in part due to Churchill's "Germany first" emphasis. Australia started to look to the United States for allegiance and advanced defense technology. We don't use enough in my opinion still to often using second rate European equipment. I do have to add that Britain made a great sacrifice in sending Prince of Wales and Repulse without a carrier to Singapore to defend against Japanese advance but it was of course ineffective considering the lack of a carrier. To an extent Australia is to blame, in the 1930's defense expenditure dropped to 1% while Britain was at around 4% at the time but certainly technical help from the UK did not come when it was needed because of sustained protectionist sentiment within British aviation industry.

If I'm not mistaken, the FAA did not have fighter aircraft comparable to the Japanese Army or Navy fighters. Not sure that a carrier would have helped. Also, Singapore was taken by land. A single carrier would not have provided sufficient air cover to change the course of the battle.

 

[parsifal]

If I'm not mistaken, the FAA did not have fighter aircraft comparable to the Japanese Army or Navy fighters. Not sure that a carrier would have helped. Also, Singapore was taken by land. A single carrier would not have provided sufficient air cover to change the course of the battle.

I agree that a single carrier was unlikely to have affected the outcome overall but in particular the land battle. however, the invasion relied on seaborne attacks at Khota baru and also within siam, at singora. There was another overland force advancing through Bamgkok, but was several days away from engaging the British in Malaya. these several days of delay were critical, as if they had been given, the Indian III corps may have bedded down better in the northern provinces.

British defence was centred around the aggressive use of Battleships Prince of Wales and Repulse, to get in and disrupt the invasion forces as much as they could. they never got close to doing that, because of a lack of aircover. that lack of aircover allowed roughly 60 G3Ms and a handful of G4Ms, themselves completely devoid of fighter escort, to deliver textbook attacks on the Britishs battlewagons and sink them. The issue of whether British Carrier fighters were superior or not isnt really relevant. Its more relevant to compare the performance of the british Carrier fighters of HMS Indomitable to the performance of those G3Ms and G4Ms. From memory Indomitables CAG was 22 Sea hurricanes, 12 Martlet IIs and 16 Albacore Night strike torpedo bombers. whether or not those 34 fighters could save PoW and the Repulse is certainly arguable. Whether or not Fce Z could have stopped the ivasions is even more problematic. But the presence of even a single modern carrier would have made things a LOT more difficult for the Japanese attacking formations.

As to a single carrier not providing enough air cover for the land battle, id agree with that, but then thats not the relevant question, either. It is whether the CAG could provide enough aircover for the two BBs, and whether the two BBs could then disrupt the seaborne operations that were integral to the japanese invasion. The British had certainly demonstrated in spades in the preceding two years that their CAGs were very efficient and could dispute enemy controlled airspace, even when heavily outnumbered

 

[RCAFson]

If I'm not mistaken, the FAA did not have fighter aircraft comparable to the Japanese Army or Navy fighters. Not sure that a carrier would have helped. Also, Singapore was taken by land. A single carrier would not have provided sufficient air cover to change the course of the battle.

Indomitable carried 9(or maybe 12) Sea Hurricanes 1Bs, 12 Fulmars and 24 Albacores. The Sea Hurricane was certainly comparable to the A6M, with roughly equal or better low level speed, but since the historical IJN strike aircraft were unescorted, IJN fighters might not have been a issue, in which case the Sea Hurricanes, and the Fulmar IIs would have created havoc amongst the escorted bombers.

 

[parsifal]

Indomitable carried 9(or maybe 12) Sea Hurricanes 1Bs, 12 Fulmars and 24 Albacores. The Sea Hurricane was certainly comparable to the A6M, with roughly equal or better low level speed, but since the historical IJN strike aircraft were unescorted, IJN fighters might not have been a issue, in which case the Sea Hurricanes, and the Fulmar IIs would have created havoc amongst the escorted bombers.

The intended CAG was beefed up for the Z operation, to the point i indicated. It never reeceived all 22 of the allocated Sea Hurricanes, but should be assumed as having received them if we are going to hypothesize

 

[Koopernic]

There we have two more "revolutionary" aircraft:
The A6M "Zero" who massive range allowed it to turn up in all sorts places. It's range made it a force multiplier.
Likewise the G4M "Betty" Bomber whose massive range allowed the IJN to cover huge swathes of the Pacific.

Even a dozen Fulmars, let alone the more effective Sea Hurricane (21 fighters in all) stood a good chance of disrupting the unescorted and generally unarmored Japanese medium bombers with their unprotected fuel tanks given what we now know about the advantage of fighter over bomber.

Prince of Wales and Repulse both had air warning radar Type 271 as would any RN aircraft carrier this being 1 year after the Bismarck's loss and radar had progressed on both sides. PoW added blind fire capability against surface targets from Type 284M (I assume it was the M Modified upgrade which added blind fire against ships given the fit-out in late 41) and 4 x Type 285 50cm anti aircraft gunnery radars that while not fully blind fire capable (accurate range and bearing but poor height find ability) did add accurate range data into the High Angle Fire Control System for the heavy AAA and 4 x Type 282 radars that ranged for the Pom Pom. Unfortunately 3 of the 4 were out of service due to lack of spares. PoW, had its radar have worked, had a formidable night fighting ability and reasonable AAA capability (She destroyed several attacking aircraft) and might have done well against the IJN at night despite the much vaunted Japanese night optics.

 

[Glider]

I admit had the forces met at night it would have been interesting. Both navies are well trained at night fighting, the Japanese have the optics and the long lance torpedo's but the RN have radar. I wouldn't fancy calling it.

 

[Koopernic]

I admit had the forces met at night it would have been interesting. Both navies are well trained at night fighting, the Japanese have the optics and the long lance torpedo's but the RN have radar. I wouldn't fancy calling it.

If the task Force Z had of had the aircraft carrier Indomitable it could have mounted a successful defense against air attack but HMS Indomitable had run aground in the Caribbean and was delayed by repairs. I really don't know what the RN British Strategy was but given the far greater force the IJN Japanese had I would imagine they would try and behave like a German raider: strike with surprise if favorable circumstances but withdraw if not: keep the enemy running around.

Torpedo bombers in their attack are limited by torpedo release limits so the Swordfish and Albacore biplanes are not nearly so restricted as one might imagine. In fact the Swordfish's ability to attack very low was probably more of a defense than speed, Bismarck's gunners couldn't keep sight of the Swordfish as they darted and disappeared beneath waves crests in the pitching sea, dropping torpedoes into the peaks of waves, and what I think must have been twilight or semi darkness. Swordfish at the time already had radar and so I imagine did the Albacore. Torpedo attacks at night might have been a possibility, though I don't know the practicalities of this: The Germans had a very good radar altimeter (FuG 101a) to keep themselves out of the water but I suspect the radar would allow the British carrier aircraft to find the Japanese warships but I imagine starlight was still needed.

Perhaps all that a Battleship needed was a small fast aircraft carrier the size of a cruiser, 7000 tons and at most 8-9 aircraft to defend itself and scout.

 

[parsifal]

Historically Indomitable was unlikley to have made it in time to join the task group in time. She was in the bahamas as of 3 November, when she ran aground, still working up. her air group was trained, but lacked the finer skills of the more experienced fleet units like Ark Royal. The Ark Royal and the Ilustrious were the specialist night capable CAGs, and whilst the Indomitable was nominally rated for night ops, really needed some further months of work up to be considered effective in that role.

Whilst the addition of a carrier to Force Z would have been a massive boost to its overall capability, the task force was anything but a balanced force. The Admiralty was against the idea, and in my opinion really dragged their feet over the whole formation after Churchill overruled their objections. The Admiralty wanted to take more time and build up a more balanced fleet built around the older battleships a balanced force of carriers and escorts, which eventually became the Eastern fleet, and finally the British Pacific Fleet. Both camps....churchill on the one hand and the Admiralty on the other, made valid points in the debate. Churchill needed a real deterrent in a hurry, to impress and intimidate the Japanese, but once this bluff was called, the british really should have withdrawn these highly valuable ships until a more coherent balanced force could be formed.

My opinion, based only on opinion, is that the best option might have been to rebase the poW and Repulse to the NEI, for the time being restoring the Hermes to operational status until the arrival of the Indomitable. Indomitable Hermes (with a proper CAG) and the Dutch destroyers and cruisers, might have posed a credible threat on which toi base the defence of Java. The defence of Java was a more realistic option, in my opinion to trying to hold Malaya. Java retained in Allied hands could mean that Singapore could be re-supplied Malta style for an extended period. And it was the defence of Singapore, not Malaya that was critical to the British position in the Far East.