Bistol Type 153 wins the F.37/35, no W. Whirlwind

[tomo pauk]

Pretty conventional Type 153 was to be powered by a Bristol Hercules, armed with 4 cannons (per spec), and was among the 1st designes supposed to have the bubble canopy. Let's say Bristol's design wins instead of Westland's.
Will the RAF be better off, or not? Possible repercussions on future British, German and/or US fighter designs? The FAA version?

picture (not the best; the 153 is at the top right)

 

[Admiral Beez]

Pretty conventional Type 153 was to be powered by a Bristol Hercules, armed with 4 cannons (per spec), and was among the 1st designes supposed to have the bubble canopy.

Given that the Bristol Type 153 was never built either as a finished aircraft or mockup or even AFAIK a reduced scale wind tunnel model, I don't think we may much to go on. How fanciful are these drawings - is there anything official from Bristol's design table?

The Bristol Hercules has little to no history in single-engined applications, especially in the high performance fighter role. But since its successor the Centaurus exceled in the single engine fighter role we can safely assume the Hercules could be sorted. The bigger issue is that we don't see the Hercules entering widespread service until well into 1941. By 1942 the FAA is flying Seafires and Martlets and the RAF Spitfires and Typhoons. The Type 153 might be declared a distraction and shelved, like the Bristol Type 146 shown below.

But I refuse to join the resident contrarians here who default to telling us why something can't or won't be done. So, what I wish Bristol had done in the 1930s was to follow Fairey's example of the Swordfish, whereupon the latter was made as a speculation, without a contract. Bristol knows it's working on the Hercules, so make a speculative fighter for the FAA designed "for-but-without" the Hercules as the intended powerplant when its available. By 1937 single-seat carrier fighters are the now and future - the A5M, F3F and Dewoitine D.373 having entered fleet service in 1936, with the F4F and Sea Gladiator first flying the following year. There's enough to go on for a successful firm like Bristol to invest in their own all-metal, monoplane carrier fighter powered by the Taurus but ready for the Hercules. It will need more fuel and substance than the diminutive 146 above. If that's an early Type 153 that's good.

 

[Shortround6]

resident contrarians here who default to telling us why something can't or won't be done.

I refuse to believe in pixie dust or anti-gravity paint or perpetuation motion power plants.

Likewise the need for time machines or planes with all the stretch that is needed to get the idea to come out right.

The Taurus did not predate the Hercules, or at least not by very much.
In 1940 there was one Beaufort squadron.
The Albacore didn't begin to equip a service squadron until March of 1940.

A Hercules was just under 50% larger/heavier than a Taurus.
That is bare weight. Allow for a similar increase in the entire installation.
The Taurus, in service, was a low altitude engine.
In 1938-40 the sleeve valve Bristol engines were darn close to a liability.

Designing a 4600lb fighter with a Mercury (under 1100lb) engine so you can upgrade to the 1900lb engine when it becomes available requires quite a bit of foresight.

A lot of British designs (and other peoples) required either pixie dust or antigravity paint to meet the performance specs.
The Bristol 153A (the twin) was one such airplane. The Idea that you could power a fighter with 4 20mm cannon using a pair of 15.6 liter engines required an extra large dose of the sleeve valve cool aid.

 

[fastmongrel]

Bristol aircraft designs and speed don't seem to go together. Bristol could talk a good top speed but never got any where near the paper speed.

 

[tomo pauk]

Bristol aircraft designs and speed don't seem to go together. Bristol could talk a good top speed but never got any where near the paper speed.

Bristol was not promissing the moon with the Type 153 - under 360 mph. Perhaps they should've promised 400 mph?

 

[Shortround6]

Bristol was not promissing the moon with the Type 153 - under 360 mph. Perhaps they should've promised 400 mph?

they had to knock off 40mph because they specified a cockpit heater

Some of the published specifications for the single engine Bristol 153 include a

wingspan of 37ft, a wing area of 204 sq ft, a fully loaded weight of 6092lbs, an 85imp gallon fuel load.
300mph at sea level, 357mph at 12,500ft, initial climb rate of 3,580ft/min

and of course the four 20mm Hispano guns with drums.

Now throw in the Hercules HE.IS engine which is rated at 1295hp at unknown altitude.
Please note that Lumsden does not list a Hercules HE.IS version, not to say he was infallible but it makes looking up the specifications hard.

He does list a dry weight of 1845lbs for the Hercules I.
The Hercules I & II were rated at 1375hp at 4,000ft.
Perhaps the HE.IS was planned for a higher FTH?
But it would have been a single speed supercharger.

But lets compare the Bristol 153 to another fighter that has been getting a lot of attention lately.
The A6M2

 

[tomo pauk]

Now throw in the Hercules HE.IS engine which is rated at 1295hp at unknown altitude.
Please note that Lumsden does not list a Hercules HE.IS version, not to say he was infallible but it makes looking up the specifications hard.

He does list a dry weight of 1845lbs for the Hercules I.
The Hercules I & II were rated at 1375hp at 4,000ft.
Perhaps the HE.IS was planned for a higher FTH?
But it would have been a single speed supercharger.

My take is the same wrt. the HE.IS - a hi-alt version of the early Hercules engines. Or, sometingg like the FS-only version of the Hercules III?

 

[Shortround6]

My take is the same wrt. the HE.IS - a hi-alt version of the early Hercules engines. Or, sometingg like the FS-only version of the Hercules III?

Perhaps you are right, but it doesn't seem to have been made?
prototype Beaufighter? Wiki says Hercules I-IS engines? replaced in the 2nd aircraft by Hercules I-M engines.

I-IS is intermediate supercharger or full supercharger?
I-M is medium supercharger.
Further reading of Lumsden says the initial prototype engine ran as a full supercharged single speed engine and after initial runs was converted to a medium speed blower.

What I am somewhat interested in was the 1800lbs of engine in 6,000lb gross weight fighter.
again compare to the A6M2 or compare to a P-36/Hawk 75 with an R-1830 and compare the 4-6 rcmgs to the 4 Hispano guns.
Or compare the Bloch 152 with it's under 1400lb engine.

The claimed speed would have put a Fw 190 to shame while carrying a heavier load of guns.

 

[tomo pauk]

What I am somewhat interested in was the 1800lbs of engine in 6,000lb gross weight fighter.
again compare to the A6M2 or compare to a P-36/Hawk 75 with an R-1830 and compare the 4-6 rcmgs to the 4 Hispano guns.
Or compare the Bloch 152 with it's under 1400lb engine.

The claimed speed would have put a Fw 190 to shame while carrying a heavier load of guns.

Yes, the expected weight is suspiciously low. Would've went to 7000 lbs easily IMO, plus the weight of protection for pilot and fuel tanks.
Claimed (expected) speed was nothing special vs. Fw 190?

 

[Shortround6]

Yes, the expected weight is suspiciously low. Would've went to 7000 lbs easily IMO, plus the weight of protection for pilot and fuel tanks.
Claimed (expected) speed was nothing special vs. Fw 190?

Well, for an under 1300hp engine at around 12,000-12,500ft compare to the Fw 190 with it's engine only making a similar amount of power (like cruising).
The 'advantage" of the FW 190 somehow disappears and the whole FW 190 showed the British how to install radial engines story goes away

Or we can believe that Bristol (like some other British airframe makers) over estimated their speed numbers by around 30mph (the 370mph Beaufighter I?) and bring the Bristol 153 estimates more into line with most everybody's actual airplanes were actually doing. And believe that the Fw 190 did show the British some tricks on how to package a radial engine.

 

[tomo pauk]

Well, for an under 1300hp engine at around 12,000-12,500ft compare to the Fw 190 with it's engine only making a similar amount of power (like cruising).
The 'advantage" of the FW 190 somehow disappears and the whole FW 190 showed the British how to install radial engines story goes away

BMW 801C was making, for the 30 min limit, 1310 PS at 14400 ft (2400 rpm). Fw 190A-1 seems to be good for 390 mph on that setting, at least going by the two charts posted here.
More than 30 mph advantage over the Type 153 figures.

 

[Admiral Beez]

Designing a 4600lb fighter with a Mercury (under 1100lb) engine so you can upgrade to the 1900lb engine when it becomes available requires quite a bit of foresight.

The Taurus was a bad choice on my part, but my thinking is Bristol knows its got the Hercules coming, so build your fighter to accept whatever engine is available now with provision to accept the Hercules when its ready. The first Bf 109 prototypes flew with 434 kg Rolls-Royce Kestrel engines and first operational aircraft were powered by the 442 kg Jumo 210 - they knew this was smaller and less powerful, but it got the program moving along until the much heavier 756 kg DB 605 was ready. Gloster did this with their F5/34 prototype, flying with a Bristol Mercury as the intended (and designed for) Perseus was not yet ready - though Gloster had the advantage that both engines were of similar size and weight.

Bristol has the enviable position of being both the aircraft and engine designer. I don't think fairy dust is needed for someone in the Bristol aircraft design office in 1937 to walk down to the engine design office and ask, "what are you working on, how's that new 875 kg Hercules engine you first ran last year coming along? By Jove, potentially over 1,100 hp?! I'll incorporate that into our new fighter proposal - we'll fly the prototype and if necessary the first batch with another 55 in diameter radial, likely Pegasus or Perseus (both under 500 kg) and add weight to the nose as ballast."

Bf 109B with Jumo 210 engine (approx. 442 kg)

Bf 109E with DB 605 (approx 756 kg)

If Messerschmitt can sort out how to utilize a lightweight engine whilst the intended larger engine is being prepared I don't see why Bristol couldn't.

 

[Shortround6]

The first Bf 109 prototypes flew with 434 kg Rolls-Royce Kestrel engines and first operational aircraft were powered by the 442 kg Jumo 210 - they knew this was smaller and less powerful, but it got the program moving along until the much heavier 756 kg DB 605 was ready.

You skipped a couple of steps.
There was only one 109 that flew with RR Kestrel engine,
The Jumo 210 was running late and in order to get the airframe into flight test the Kestrel was used. They did use at least or more different versions of the Jumo 210s and they built hundreds of 109s with Jumo 210 engines. They were expected to eventually use the DB 600 engine ( a 565kg engine? ) but which version of the Jumo 210?
And lots of luck trying to stick a DB605 into even a Bf109D airframe.

Gloster did this with their F5/34 prototype, flying with a Bristol Mercury as the intended (and designed for) Perseus was not yet ready - though Gloster had the advantage that both engines were of similar size and weight.

Part of the similar size and weight were because the Mercury and the Perseus used same number of cylinders of exactly the same size (146mm bore and 165 mm stroke). They also ran at the max RPM.
Why people expected the planes powered by the Perseus to have significantly better performance requires the special paint or strong drink before signing the contract/s.

If Messerschmitt can sort out how to utilize a lightweight engine whilst the intended larger engine is being prepared I don't see why Bristol couldn't.

because Messerschmitt never intended to use an engine the size/weight/power of the DB605 in 1934-36
They went from the 600hp Jumo 210 to a 720/730hp Jumo 210.
They tried a few roughly 1000hp DB 600s and switched to the DB 601A, took two years to get DB 601Ns, then DB 601Es and finally in 1942 they got the DB 605.
Of course the 109, when it got the 601Ns got a modified wing, got a modified tail, other changes?

Please look at the Curtiss Hawk series. The wing alone went from about 850lbs in the P-36/Hawk 75 to about 1000lbs in the P-40toP-40C/Hawk 81 series to about 1100lbs in the P-40D-N/Hawk 87 series. you don't build the same wing and fuselage for a 6,000lb airplane that you do for an 8,000lb plane even if they have the same shape. A great recipe for inflight structural failures. Using the same structure for the small engine early version while you wait for the big engine to come along means a slower plane with less climbing speed and less payload (fuel, weapons, etc) than a proper size/weight airframe for the engine will give you.

 

[Admiral Beez]

You skipped a couple of steps.
because Messerschmitt never intended to use an engine the size/weight/power of the DB605 in 1934-36

All good points. The difference for Bristol is that I'm suggesting they are intending to use the Hercules in their new fighter, but since Roy Fedden's dept needs more time, a less powerful, yet available Bristol radial will go in place of the Hercules. So a swap out rather than indepth Bf 109 D to E redesign in the plan. It's the only way I can see the Type 153 entering service in place of the Whirlwind.

Or just forget all this, and we delay this fighter until the Hercules is good and ready. The challenge there is by then the Spitfire, Hurricane, Typhoon, Fulmar and Martlet have all the resources and glory, with the Tempest, Firefly and other lend lease fighters soon to enter the picture, so there's no need for the Type 153.

Best plan is the expedite the Hercules program and get the Type 153 prototype flying with its intended engine in 1938.

 

[Admiral Beez]

Part of the similar size and weight were because the Mercury and the Perseus used same number of cylinders of exactly the same size (146mm bore and 165 mm stroke). They also ran at the max RPM.
Why people expected the planes powered by the Perseus to have significantly better performance requires the special paint or strong drink before signing the contract/s.

Beyond finding another platform for sleeve valves I've never understood the point of the Perseus. Just make an incrementally better Mercury.

 

[Shortround6]

Or just forget all this, and we delay this fighter until the Hercules is good and ready. The challenge there is by then the Spitfire, Hurricane, Typhoon, Fulmar and Martlet have all the resources and glory, with the Tempest, Firefly and other lend lease fighters soon to enter the picture, so there's no need for the Type 153.

Best plan is the expedite the Hercules program and get the Type 153 prototype flying with its intended engine in 1938.

The Hercules used the same cylinders as the Perseus so at any given point in time (stage of development/type of fuel available, etc) the Hercules was going to give you 14/9s of the power of a Perseus ( divide Perseus by 9 and multiply by 14). A few percent off for different friction losses and or plumbing losses.

You have a few problems,

1, Bristol for the most part, didn't build good superchargers. They weren't bad but they were not in the same class as RR.
2, Bristol until the middle of war, didn't build very good engine nacelles for radial engines (or give the airframe makers any good ideas) which meant high drag for installed power. Very few other people were building good radial installations either.
3, The Hercules was a little on the small side, It was world class when it started out in 1936-37 but it fell behind a little bit by 1940-42.
Hercules was 2,360 in³ (38.7 L) as were the French Gnome-Rhone engines. The US had the R-2600 and in 1940 the R-2800, Germans were working on the 2550 cu in (41.8 L) and the Russian ASh-82 was 2514 cu in ( 41.2 L)

and if you are looking for a FAA fighter you may started with the wrong airframe. The US may have mucked things up with the F2A Buffalo but they started with 208 sq ft of wing on a 5,000-5300lb fighter. They also has some of the biggest flight decks in the world. a 6,100lb fighter with a 204 sq ft wing in prototype form is only going to get a heavier wing loading as it gets developed.

BTW

Used a DB601 engine of about 590-610kg.
The DB 605 doesn't show up until you have round wing tips and a number of other changes to the wings. You also have the tail plane at a different height and the struts bracing the tail plain have disappeared.

 

[Shortround6]

BMW 801C was making, for the 30 min limit, 1310 PS at 14400 ft (2400 rpm). Fw 190A-1 seems to be good for 390 mph on that setting, at least going by the two charts posted here.
More than 30 mph advantage over the Type 153 figures.

Bristol was doing 357mph at 12,500ft (3660 meters?)

You may be right.
But the Bristol is claiming a high speed for that amount of power.

 

[tomo pauk]

You have a few problems,

1, Bristol for the most part, didn't build good superchargers. They weren't bad but they were not in the same class as RR.
2, Bristol until the middle of war, didn't build very good engine nacelles for radial engines (or give the airframe makers any good ideas) which meant high drag for installed power. Very few other people were building good radial installations either.
3, The Hercules was a little on the small side, It was world class when it started out in 1936-37 but it fell behind a little bit by 1940-42.
Hercules was 2,360 in³ (38.7 L) as were the French Gnome-Rhone engines. The US had the R-2600 and in 1940 the R-2800, Germans were working on the 2550 cu in (41.8 L) and the Russian ASh-82 was 2514 cu in ( 41.2 L)

Size (displacement) was not supposed to be a measure how good or bad the engine is, that should be "power_minus_weight_minus_size" metrics (with an eye for reliability)? Good deal of power came from the crankshaft RPM; Herules was turning 2800 rpm (later 2900), the ASh-82 did 2400 (later 2500). BMW 801C did 2700 low, and 2550 high (upped to 2700 by early 1942). Problem with the 801 was that it was not there until Autumn of 1941 (with reliability problems greater than what Sabre endured in 1942), ditto for the ASh-82. BMW 801D flew in de-rated form until October of 1942. BMW 801 was also heavier than the Hercules by ~10%. Yes, it gave better exhaust thrust than the Hercules.
Once BMW 801C is in service (Autumn of 1941), the power levels at 15000 ft:
- R-2600 (the 1700 HP version): 1250
- Hercules VI: 1340 (per Bristol data; the Beaufighter data sheets give 1500HP at 17000 ft!)
- BMW 801C: 1380 PS
- ASh-82: 1330 PS at 16000 ft (per the 'TsAGI book'; German report gives 1300 at 15000)
The less we say about French and Italian 14 cy radial engines in 1941 the better (bar the G&R 14R, but that one was not in production for obvious reasons).

Granted, anything than Hercules is a moot point for the British.

Bristol was doing 357mph at 12,500ft (3660 meters?)

You may be right.
But the Bristol is claiming a high speed for that amount of power.

Still seems pretty modest for my eyes. Even if we knock 15 mph from the Fw 190A-1 (just to be sure) on Kampfleistung, that is still almost 20 mph better than what Bristol expected from the Type 153.

 

[nuuumannn]

Since this is a what-if, you have a better aircraft, airframe/engine choice-wise of getting Petter to design the Whirlwind from the outset with Merlins and dispensing the complicated flap/cowl arrangement. Make the thing simpler and it'll be better than it traditionally was.

 

[tomo pauk]

Since this is a what-if, you have a better aircraft, airframe/engine choice-wise of getting Petter to design the Whirlwind from the outset with Merlins and dispensing the complicated flap/cowl arrangement. Make the thing simpler and it'll be better than it traditionally was.

??
Thread is specifically about the Type 153.