WW2 with no Spitfire - Hurricane being primary interceptor

[altsym]

Anyways, here's an interesting article and drawing of a hypothetical Griffon Hurricane:

So... the "ultimate what-if fighter" fuselage is still 50% fabric? According to that drawing anyways.

 

[wuzak]

It's a bit more complicated than that because Camm based his speed predictions on engine outputs that didn't always match their manufacturers claims.

I guess that's true.

He probably did his calculations on promised 2000hp engines. So when he had to use Vultures and Sabres of much less power it would have cost him a lot of speed.

The 10,700lb Tornado made 398 mph at 23300 ft with a rough running Vulture V.

A "rough running" Vulture? What is the premise for this claim?

As far as I can tell the Vulture V, while not running totally flawlessly, had little difficulty in the Tornado and exhibited none of the major reliability issues that befell the Vulture II in the Manchester. There may have been slightly lower ratings for continuous operation, but the Vulture V was still rated at 1955hp @ 3200 rpm with +9psi boost. Oh how Camm must hae missed those extra 45hp!

At least one Vulture V remained in service in a prototype Tornado, being used for contra rotating prop tests in 1943.

If the Tornado fell short of expectations because of lower power, then what was the excuse for the Typhoon? The hand built Sabre II in the prototype Typhoon only gave an extra handful of mph over the Tornado, despite having, with little doubt, all of the promised 2000hp?

A Griffon Hurricane should have been much lighter, with less frontal area and probably would have matched Camm's claims, or at least come close.

Do you think Camm was at all close to reality with the Tornado/Typhoon? What were his estimates for the Hurricane?

How did he expect the Hurricane with, presumably, teh same Griffon to outperform the Spitfire, when it was 30mph down running the same Merlins?

Some reality check - the Spitfire XII with Griffon II/VI was capable of just shy of 400mph. Not sure what the IV/XX prototype did, but the prototype XIV (VIIIG) managed 446mph, and the production 21 was good for 455mph.

 

[wuzak]

I think the Hurricane had a lot more life in it, than we give it credit for:

View attachment 233618
Morgan and Shacklady, p134.

It seems likely that the above Griffon Hurricane must have had a new wing design as well.

Amazing, the Spitfire is 30mph faster when using the same Merlin, but 14mph slower when using the same Griffon?

The Griffon Hurricane must have had a new wing - that much is certainly true. But that means a longer time to introduce the new Hurricane. The Spitfire XII was a Spitfire V (well, to start with) with a Griffon bolted on. No major new bits apart from the engine installation.

The Spitfire XII, with minimal changes to the structure, went into production in late 1942. When can we expect a Hurricane "XII"? And is there much point when the Typhoon is in production from 1941?

 

[nuuumannn]

Don't forget that the Griffon Hurricane was abandoned by the Air Ministry because it was felt to have had no future.

Shortround, Joe, take comfort in the knowledge that although we've raised exactly the same points as you, we, too have been ignored!

 

[FLYBOYJ]

Don't forget that the Griffon Hurricane was abandoned by the Air Ministry because it was felt to have had no future.

Shortround, Joe, take comfort in the knowledge that although we've raised exactly the same points as you, we, too have been ignored!

Amazing how that happens!

 

[Shortround6]

IS it just me or does this Hypothetical super Hurricane look an awful lot like a slightly warped MB 5 with a fabric rear fuselage

To give Camm his due Bristol was off by about 30mph on it's prediction for the Beaufighter. The Boffins at the RAE were handing out some bad formulas when it came to thick wing drag at high speed.

A Centaurus Powered Tornado managed 421mph although at what altitude I don't know , engine was good for 150hp more than a Sabre II 2000ft lower (2030hp at 13,250 ft vs 1880hp at 15,250ft) and 300hp more than a Vulture II ( 1710hp at 15,000ft)
Vulture V unknown? Granted the Centaurus was a radial.

 

[RCAFson]

I guess that's true.




A "rough running" Vulture? What is the premise for this claim?

The Secret Years states that the engine was running rough and couldn't develop full boost:

Two engines, the Sabre and Vulture, were proposed
by Hawker to meet the F]8/37 requirement. The former
became the Typhoon, and the latter, the Tornado. The
types were aerodynamically similar, but only a few
Tornadoes flew, of which one, P5224 (Vulture V), the
second prototype, was briefly at Boscombe from October
]941. At 10,690 Ib, handling was indistinguishable from
the Typhoon with stall at 82 mph (clean) and 61 mph
(undercarriage and flaps down), the engine ran rough at
high rpm (up to 3,200). Performance (see Table) was
comparable to the early Typhoons; the report comments that
had an extra pound of boost been available, top speed would
have been over 400 mph.

The tables of performance states that the engine only developed 8lbs of boost.

 

[wuzak]

The Secret Years states that the engine was running rough and couldn't develop full boost:

The tables of performance states that the engine only developed 8lbs of boost.

Does it give the altitudes?

The Vulture V was only rated for 9lbs of boost.

1lb of boost is likely to make a small performance improvement. But not 60mph.

 

[RCAFson]

Does it give the altitudes?

398 mph at 23300ft

 

[wuzak]

398 mph at 23300ft

I don't believe that the Vulture V had a FTH that high.

In other words, that while it was rated for +9psi boost, it is doubtful that boost could have been maintained to that altitude.

 

[tomo pauk]

The 23300 ft would be FTH with ~400 mph worth of ram. No ram, the FTH is at maybe 19000 ft?
Wasn't the Vulture V a 'fighter's engine' (the II being 'bomber's engine' - more power at lower altitudes)?

 

[Shortround6]

Without Knowing what the gear ratios in the supercharger were to make a guess and without an published Power at altitude specifications we are really guessing.

Unless somebody has got something?

 

[wuzak]

The 23300 ft would be FTH with ~400 mph worth of ram. No ram, the FTH is at maybe 19000 ft?
Wasn't the Vulture V a 'fighter's engine' (the II being 'bomber's engine' - more power at lower altitudes)?

Yes, the IV and V were fighter engines.

 

[wuzak]

Yes, the IV and V were fighter engines.

Lumsden has only got s/c gear ratios for the II.

 

[altsym]

the report comments that
had an extra pound of boost been available, top speed would
have been over 400 mph.

Atmospheric pressure is 14.7 psi @ see level. So 1 psi would in theory give you the potential of an extra 1/15th of your current power.
So a 2000hp motor for instance would equate to 120hp @ sea level. Now take into consideration the volumetric efficient of the engine,
its probably more like 80hp @ sea level, so what's the HP gain from 1lb of boost @ 23,300ft?

 

[OldSkeptic]

My own feeling is that if the money spent on Spitfire development (and procurement)was instead used to boost Hurricane development and production, that initially, up to about mid 1941, that the net result would have been positive, as more Hurricanes (3 Hurricanes for every two historical Spitfires plus historical Hurricane production), with better access to Merlin engine development (Merlin 12, 45), in a cleaned up Hurricane airframe would have resulted in a stronger RAF. However, once the 109F and FW190 arrive in numbers the situation gets a lot more difficult for Hurricanes unless it can accept a wing change. However even the existing design with modest changes might be able to hold the line until newer designs arrive in numbers.

What happened in North Africa and Malta with Hurricanes vs 190Fs was indicative of the slaughtering that would have gone on.
The Hurricane was barely competitive in 1940 (and the Spits were concentrating on the 109s to cover them), by '41 a Hurricane was just a slow target, to be taken out at will.

 

[DonL]

What will happen if the RLM would choose the FW 187 instead of the Bf 110?
What will happenn if Germany didn't attack UDSSR, but concentrate only at GB?
What will happen if the RLM had not done the advertisement of the Bomber B, so the FW 190 longnose with DB 603 are available at beginning 1943?

This whole Hurricane thread (also Hellcat vs Spitfire) is basing on ex post knowledge, nobody knows at 1936-1939 (at which timeline the decision are made), what will happen at 1940/41/42/43.
To bet one a weaker "horse" could be very dangerous, if things didn't go as imagined.

 

[Shortround6]

Atmospheric pressure is 14.7 psi @ see level. So 1 psi would in theory give you the potential of an extra 1/15th of your current power.
So a 2000hp motor for instance would equate to 120hp @ sea level. Now take into consideration the volumetric efficient of the engine,
its probably more like 80hp @ sea level, so what's the HP gain from 1lb of boost @ 23,300ft?

It is actually worse, 14.7lbs is ZERO boost. 8lbs boost is 24.7lbs total manifold pressure. 9lbs is 25.7lbs, difference is about 4%

Superchargers tend to make up for "volumetric efficiency", not completely though. An aircraft engine measures the pressure inside the manifold or leaving the supercharger. Altitude doesn't enter into it until the supercharger can no longer supply the required manifold pressure.

 

[RCAFson]

It is actually worse, 14.7lbs is ZERO boost. 8lbs boost is 24.7lbs total manifold pressure. 9lbs is 25.7lbs, difference is about 4%

Superchargers tend to make up for "volumetric efficiency", not completely though. An aircraft engine measures the pressure inside the manifold or leaving the supercharger. Altitude doesn't enter into it until the supercharger can no longer supply the required manifold pressure.

My understanding is that full boost wasn't available because the engine couldn't develop full RPM, so the power difference might be similar to a Merlin at 2850 RPM/8lb boost and at 3000rpm/9lb boost, which is somewhat more than 4%.

 

[RCAFson]

What happened in North Africa and Malta with Hurricanes vs 190Fs was indicative of the slaughtering that would have gone on.
The Hurricane was barely competitive in 1940 (and the Spits were concentrating on the 109s to cover them), by '41 a Hurricane was just a slow target, to be taken out at will.

With greater number of aircraft available, more Hurricanes can be flown as top cover, reducing the risk of being bounced.