Supermarine Type 327

[wuzak]

Comparison between the Typhoon and the Type 327 - they were essentially designed to the same requirement.

In imperial units

Type	Type 327	Typhoon
Span (ft)	40	41.58
Gross Area (sq.ft)	304	279
Length Overall (ft)	33.5	31.96
Height on Wheels (static) (ft)	9.75	15.33
All Up Weight (lb)	11,312	11,400
Engine	Merlin RM.2SM	Sabre IIB
Number Engines	2	1
Power (bhp)	1,265	2,200
Total Power (bhp)	2,530	2,200
Wing Loading (lb/sq.ft)	37.21	40.86
Power/Mass (hp/lb)	0.22	0.19
Max Speed (mph)	465*	412

In metric units

Type	Type 327	Typhoon
Span (m)	12.19	12.67
Gross Area (m²)	28.24	25.92
Length Overall (m)	10.21	9.74
Height on Wheels (static) (m)	2.97	4.67
All Up Weight (kg)	5,131	5,171
Engine	Merlin RM.2SM	Sabre IIB
Number Engines	2	1
Power (kW)	943	1,641
Total Power (kW)	1,886	1,641
Wing Loading (kg/m²)	181.69	199.5
Power/Mass (kW/kg)	0.37	0.32
Max Speed (km/h)	748*	663

* Speed for the Type 327 is estimate only. I haven't found confirmation, but I think the estimated speed of the Typhoon was much higher than the actual end result.

The Type 327 was very much the size of the Typhoon, but with approximately 15% extra power.

By the time the 327 would have made it into service, the engine would most likely have been replaced with 20-series engines, which would give slightly more power than was used for the estimate.

 

[parsifal]

But shouldn't we compare estimates to estimates, rather than estimates to actual speed. inevitably the calculated values will I think, tend to be optimistic. The best we can do is to compare what the typhoon was expected to achieve, rather than what it actually achieved, and then compare that to what this new type was expected to achieve. We cant compare actual performance, which would be better, but the type 327 was never made.

 

[wuzak]

But shouldn't we compare estimates to estimates, rather than estimates to actual speed. inevitably the calculated values will I think, tend to be optimistic. The best we can do is to compare what the typhoon was expected to achieve, rather than what it actually achieved, and then compare that to what this new type was expected to achieve. We cant compare actual performance, which would be better, but the type 327 was never made.

I don't have estimated performance for the Hawker Typhoon.

I believe it may have been similar to the Type 324, which was its direct competitor from Supermarine, at around 450mph top speed.

 

[Shortround6]

According to Wiki the squadron with Whirlwinds wasn't operational in time for the BoB and the aircraft were being delivered slowly. At one stage they had 5 Whirlwinds, all of which were unserviceable.

Of course if somebody had bothered to to tell Westland that the Whirlwind was a priority and to slow down Lysander production a bit things might have been different

 

[Shortround6]

The "estimate" for the Beaufighter was 370mph using Hercules engines running on 87 octane.

This rather shows that something was a bit off with speed estimates of the time once you got much over 300mph.

 

[GregP]

It was that pre-war German ultra high-drag paint they sold to the Brits that did it. The purchasing department only translated the "ultra" part and bought it on that basis.

 

[parsifal]

That sounds a lot like that british pilots ate carrots so they could see in the dark.....

 

[GregP]

They also drank Spitfire Ale and thought it would be easy! Of course the Germans drank Reich Mark Ale and didn't buy into it at all.

It all resulted in a beer war, often times confused with the Boer War.

Sometimes like-sounding things reault in misunderstandings.

I'd rather have a bottle in front of me than a frontal lobotomy.

 

[Koopernic]

The "estimate" for the Beaufighter was 370mph using Hercules engines running on 87 octane.

This rather shows that something was a bit off with speed estimates of the time once you got much over 300mph.

There seems to have been a problem estimating the effects of compressibility in either the British Air Ministry or British industry. Mitchell or the folks at supermarine seem to have at some level understood this as the issue was known. It seems quite a few aircraft had issues here: The Welkin in dives, the Typhoon and the Beufighter you've just mentioned. I've read that it was the air ministry that wanted or recommended the thick wing that limited the Typhoon.

It doesn't quite seem to have been an issue with the German types, perhaps because of a rapid buildup of high speed win tunnels after the nsdap took power. Typically the manufacturer would supply an estimate and then the Luftwaffe's technical office or RLM would criticise it. Granted the manufacturers estimates were high but not too far out, at least in my reading so far. 310->370 is a huge error.

 

[wuzak]

I don't think the Air Minstry had anything to do with the thickness of the Typhoon wing. I believe it was all down to Camm and his team. They had done teh same with the Hurricane as well.

Supermarine spent most of the '20s developing racing sea planes for the Schneider Trophy, culminating in the S6B. This gave them a good grounding in high speed aircraft, something that Hawkers lacked.

That said, the Type 327 does have a very thick wing, at least in the inner part between fuselage and engine.

 

[wuzak]

Not sure with the Beaufighter, but I think what it ended up being wasn't quite the same as what was the basis for the estimation.

 

[razor1uk]

....That said, the Type 327 does have a very thick wing, at least in the inner part between fuselage and engine.

True, some of that thickness was to ensure the required G-Loaded stiffness between the engines and the fusalage, also it would ensure ratio wise, that the tips would stall first I think, ensuring the low speed stall at ok-ish AoA that was familiar to Spitfire pilots..

 

[Shortround6]

That may be but according to some accounts it was the 370mph estimate that lowered the interest in the Whirlwind. Two twins with near the same armament (never mind the Beaufighters reloads) and near the same speed but the Bristol gets to use Beaufort tooling? Might be in service quicker?

Not saying this reason alone killed the Whirlwind, just another 'straw' on the Camel.

I am not sure what the division was between the air ministry and the RAE. The RAE giving advice to the manufacturers.

I am not sure what, if any, research departments the individual manufacturers had in the 1930s, like wind tunnel facilities. In the US few, if any, manufacturers had their own wind tunnels of any sort although some companies did contract with a few universities for individual studies or projects. Number of tunnels in the US roughly tripled between 1939 and 1945.

 

[razor1uk]

Germany and I think the Soviet Union had most of the Worlds windtunels, pre war, at least those that were powerful and large enough for something approaching 1/4 scale and larger, with powerful enough motors/engines for high speed on the same site - many establishment had to make smaller 'scalled' and less as accurate models to simulate higher speeds in small tunnel.

Many of the German windtunnels and altitude/condition chambers were either coipied or transplanted post WW2 to the allied nations as part of reperations and rebuilding/re-equiping.

A modern engineering equivalent to the rarity of proper windtunnel establishments back then, I think, would be 'plasma nitriding chambers', used to anneal and harden Crankshafts and other parts that need toughening with a surface gas finishing too.

There is one in near Hinckley (Triumph Motorcycles), perhaps another in EU/Germany, and perhaps only another 3 to 5 around the rest of the World, but back then, there was less of what we now even think of of a basic windtunnel/aero facility, and that was considered then amongst the best then known.

 

[Shortround6]

One book gives the following US wind tunnels before WW II, excluding such things as the Wright brothers tunnel.

1919.......Stanford University................round.........6ft throat
1920.......Air Corps, Wright Field............round.........5ft ""
1923.......Curtiss................................round.........7ft '" "
1925......University of Michigan.............octagonal...8ft " "
1925......New York Univerdity...............square........9ft " "
1927......NACA Langley.......................round.........20ft " "
1928......NACA Langley.......................round......... 5ft " "
1930......NACA Langley.....................rectangular...7 X 10 " "
1930......Calif, Institute of technology...round.........10ft throat
1931......NACA Langley.....................rectangular...full Size
1936......NACA Langley.......................round......... 8ft " " high speed
1937......Mass. Institute of technology.. Elliptical.....10 ft.

By the end of WW II the number is supposed to be about 40.

 

[wuzak]

But shouldn't we compare estimates to estimates, rather than estimates to actual speed. inevitably the calculated values will I think, tend to be optimistic. The best we can do is to compare what the typhoon was expected to achieve, rather than what it actually achieved, and then compare that to what this new type was expected to achieve. We cant compare actual performance, which would be better, but the type 327 was never made.

I don't have estimated performance for the Hawker Typhoon.

I believe it may have been similar to the Type 324, which was its direct competitor from Supermarine, at around 450mph top speed.

I received a message from former member J.A.W.:

'Typhoon Tempest at War' by Reed Beamont 1974, states the following.

"Hawker had estimated early in the development phase that their new aircraft would have a maximum level speed in excess of 460mph. The Air Ministry reduced this forecast to 428mph, but in the event early Typhoons were only just able to top 400mph..."

 

[wuzak]

That may be but according to some accounts it was the 370mph estimate that lowered the interest in the Whirlwind. Two twins with near the same armament (never mind the Beaufighters reloads) and near the same speed but the Bristol gets to use Beaufort tooling? Might be in service quicker?

Not saying this reason alone killed the Whirlwind, just another 'straw' on the Camel.

I think what killed the Whirlwind was that the Spitfire, Hurricane and Typhoon all ended up with cannons. And two of them matched or outperformed the Whirlwind.

And, of course, the decision to cancel the Peregrine.

 

[parsifal]

I received a message from former member J.A.W.:

Thanks. Appreciate the response very much. Previously, the estimated top speed of the Type 327 was 748 kmh was it not, or 460 mph, which is as near as dammit the same as the estimated speed as the typhoon. The Type 327 had 16% more power, but needed two engines to do it. We haven't considered the additional drag generated by having two props, but it may be that 15% additional power might not be enough to cover that.

I assume the two aircraft were built to the same specification, so really it gets down to which one fulfilled the ministry's specification. Wasn't the typhoon intended as a response to spec 18/37, which called for a minimum speed of 400mph and would be a successor to the hurricane. typhoon ended up as a not particularly effective fighter, but was a very effective FB. It was designed to accommodate multiple engine types which should have increased the chances of success.

I can understand why the typhoon was accepted over the type 327, given the intended role of the type. its hard to see the air ministry concluding the type would meet that need for a replacement of a single seat, single engined fighter better than the typhoon.

Not to say that the type 327 did not have a lot of obvious potential. It was probably abetter proposition than the beaufighter. But it was conceived as aresponse to a specification that it appears ill suited to meet, and therein lies its reasons for abandonment. If the customer specifies he wants a sedan, and you come up with a utility, no matter how good your design, you have not met the design brief.

that's how it looks to me at least.

 

[wuzak]

The Typhoon (and Tornado sister aircraft) was designed to meet specification F.18/37 for a fighter armed with 12 rifle calibre machine guns and was to replace the Hurricane and Spitfire.

Supermarine's submissions were the Type 324 and Type 325. Each features a choice of a pair of Merlins or Taurus, the Type 325 differing in being a pusher type.

The Type 327 was to a later spec calling for a cannon armed fighter.

 

[Koopernic]

There were big holes in aerodynamic theory still around thus time:

http://history.nasa.gov/SP-4103/app-f.htm
"It was agreed that Mr. Jacobs would prepare a memorandum pointing out the possibility of increasing the speed of airplanes by the use of boundary-layer control to obtain high lift, thus enabling the designer to cut down the wing area, increasing the wing loading, which obviously would decrease the total drag.45


The memorandum Jacobs turned in six days later may properly be called the result of Freeman's dissatisfaction with the pathless ness of work on research authorization 201, Helmís criticism of the pursuit of lift instead of drag reduction, the independent work Jacobs had been doing under another research authorization, and finally Jacobs's own genius for synthesis and conceptualization. He had found that increased wing loading of a "normal airfoil" produced "surprisingly large" increases in speed. He hypothesized seven reasons for this, some of which he felt had been neglected. The reasons ranged from the transparently logical to the seemingly incongruous. Smaller wings, for example, would clearly result in reduced wing-surface cover weight. But the argument that higher speed would result in fuel-weight savings sounds to the uninitiated like hurrying up to get there before the gas runs out.46"

since German aircraft tended to use relatively high wing loadings they probably did quite well out of this phenomena. Supermarines work on racing must have given them a practical understanding of wing thickness.

There are many kinds of wind tunnel, large scale, high speed, VDT variable density wind tunnel.

VDT was very important as a subscale model must be run at a higher pressure to compensate for Reynolds effects.

Im inclinded to trust supermarines estimates; especially the 300 series after the spitfire.