Napier-Heston fighter instead of Napier-Heston racer?

[tomo pauk]

The small, sleek and powerful Napier-Heston racer was supposed to beat the German record aircraft by early 1940s. Unfortunately, that didn't happened.

For the needs of this thread, let's have people at Heston design a sleek, powerful, if not very small fighter with the Sabre instead of the racer. Talk 250-270 sq ft (not 160 sq ft as on the racer) wing of thin profile , 'blended' ram air intakes, smart cooling system etc. 4 cannons as weaponry, radios, some protection for pilot and fuel tanks etc. 130-140 imp gals of internal fuel for starters. 'Normal' cockpit canopy. Use of wood panels is okay, but all-light-alloy construction is also okay, and probably better. Yes, someone else will need to make them, since Heston company has no production facilities worth speaking about.

 

[NevadaK]

Interesting proposal, Tomo.

I'm not sure Heston had the engineering capacity to design such a fighter. My understanding is that Napier led the design and Heston was involved to help realize the project. Heston was also involved in other war critical projects including leading the development of the PR Spitfires.

The Heston Racer is one of those great what-ifs. To me it's similar to the HE-100. Spurs "What could have been." Debates.

 

[tomo pauk]

The Heston Racer is one of those great what-ifs. To me it's similar to the HE-100.

Now that you mentioned it - yes, looks kinda He 100 that gained a few pounds No wonder, the Sabre was a veritable chunk of an engine.

I'm not sure Heston had the engineering capacity to design such a fighter. My understanding is that Napier led the design and Heston was involved to help realize the project. Heston was also involved in other war critical projects including leading the development of the PR Spitfires.

Be it as it might, a 'Heston fighter' might've given the RAF what Typhoon was supposed to give - a real world-beater among the fighters.

 

[Shortround6]

The small, sleek and powerful Napier-Heston racer was supposed to beat the German record aircraft by early 1940s. Unfortunately, that didn't happened.

For the needs of this thread, let's have people at Heston design a sleek, powerful, if not very small fighter with the Sabre instead of the racer. Talk 250-270 sq ft (not 160 sq ft as on the racer) wing of thin profile , 'blended' ram air intakes, smart cooling system etc. 4 cannons as weaponry, radios, some protection for pilot and fuel tanks etc. 130-140 imp gals of internal fuel for starters. 'Normal' cockpit canopy. Use of wood panels is okay, but all-light-alloy construction is also okay, and probably better. Yes, someone else will need to make them, since Heston company has no production facilities worth speaking about.

Basically you want a Hawker Tempest early.

Take out the engine and tail wheel, change everything else, put the engine back in and bolt the tailwheel back on.
It would also help to somebody fix the supercharger on the Sabre.

Speed record planes make lousy fighters because after you fix everything you need to fix to turn them into fighters they are surprisingly, not any faster than a plane using the same engine that was designed to be a fighter.

Had the Typhoon and Sabre actually worked like they were supposed to it might have been remembered differently. There was nothing Heston could have done about the engine in 1941-42.

Now please note that the "chin" radiator only sticks down about 1/2 way past the bottom of the fuselage/wing.
You don't have to do what the Typhoon did but the leading edge of the wing from the Fuselage to the just short of the inner guns was a 35imp gal fuel tank so if you want to use leading edge radiators? Tempest did get around that by moving the cockpit back about 21 in but that means a lousier view for landing and tank-off and for deflection shooting.
Also note that the "chin" also held the oil cooler and the carb intakes.
Also note that the Tempest not only used a thinner wing but it moved the max thickness to 37.5% instead of 30% which was much more typical of the time. They had also figured out that improving the wings quality of construction (surface finish) was important so when we look at the difference between the Typhoon and Tempest there are 3 differences in the wing. What each change contributed to the total change I don't know but trying to design an Early Tempest in 1938/39 and not employing all the changes means a smaller improvement.

 

[tomo pauk]

Basically you want a Hawker Tempest early.

Take out the engine and tail wheel, change everything else, put the engine back in and bolt the tailwheel back on.
It would also help to somebody fix the supercharger on the Sabre.

Speed record planes make lousy fighters because after you fix everything you need to fix to turn them into fighters they are surprisingly, not any faster than a plane using the same engine that was designed to be a fighter.

See here:

if not very small fighter with the Sabre instead of the racer.

In other words, the racer never happens.

 

[Shortround6]

Heston's most up to date, advanced aircraft before the Racer.

4-5 seat cabin monoplane with retracting landing gear and a wooden wing.
DH Gypsy-Six engine with or without controllable pitch prop.

Without the 'Racer' Hestons's entry into the world of fighter design would be just about non-existent.

Heston started work in 1938 and the ill fated first flight was June 12th 1940 which is too early to incorporate any 'laminar flow' air foils.

 

[tomo pauk]

Heston's most up to date, advanced aircraft before the Racer.
4-5 seat cabin monoplane with retracting landing gear and a wooden wing.
DH Gypsy-Six engine with or without controllable pitch prop.

Trim looking A/C

Heston started work in 1938 and the ill fated first flight was June 12th 1940 which is too early to incorporate any 'laminar flow' air foils.

Not that I'm championing any of the laminar flow wings here - there is a whole rainbow of wing profiles going from the 19% thick wing on the Typhoon down to the thin wings of ~14% that were present on many fighter designs in second half of 1930s.

 

[SaparotRob]

It is a nice looking airplane. Yet another new one for me.

 

[Shortround6]

Not that I'm championing any of the laminar flow wings here - there is a whole rainbow of wing profiles going from the 19% thick wing on the Typhoon down to the thin wings of ~14% that were present on many fighter designs in second half of 1930s.

That is quite true but as I pointed out earlier, there were at least 3 differenced between the Typhoon and the Tempest wing. Thinner may have been the most important one, I don't know, but it was not only one. The P-40 used a 15% wing and it had trouble with compressibility. Mainly avoided by the P-40 because most P-40s couldn't fly high enough to get into trouble with compressibility.

 

[tomo pauk]

That is quite true but as I pointed out earlier, there were at least 3 differenced between the Typhoon and the Tempest wing. Thinner may have been the most important one, I don't know, but it was not only one.

Other two differences being that actual profile was more modern (we can call it laminar for all I care), while the wing area was greater (pays off at greater altitudes, and compensates for the likely loss of lift coefficient wrt. payload it will be able to carry without making much of a problem).

The P-40 used a 15% wing and it had trouble with compressibility. Mainly avoided by the P-40 because most P-40s couldn't fly high enough to get into trouble with compressibility.

I'm okay with the 15% thick wing on the Heston fighter, and I'm also okay with P-40 dive/comprehensibility behavior to be replicated on the Heston.

 

[Shortround6]

Other two differences being that actual profile was more modern (we can call it laminar for all I care), while the wing area was greater (pays off at greater altitudes, and compensates for the likely loss of lift coefficient wrt. payload it will be able to carry without making much of a problem).

I mentioned the different profile earlier. I did not mention (my fault) the greater wing area and the change in planform which went from straight taper both front and rear to elliptical. So that makes five changes, if we want more we can look at flap area and aileron placement (better roll response?)
The broader cord is where the added wing area came from. This helped allow for the 20mm cannon to be moved back as did moving the max thickness further back on on wing.
Also means that the wing wasn't quite as thin as % number indicates and while that isn't of much concern with the aerodynamics it does make 'packaging' a bit easier. fitting the 20mm guns in without having so much barrel sticking out and not changing the wing fuel tanks (or not much). Many articles of the time called the airfoil Laminar flow and while it technically may not have been trying to correct the usage/terminally of the time a this late date may cause more confusion than clarity. I just accept that it was a terminology of the time and most everybody back then understood what they were talking about even if it actually didn't work quite they way they thought. The wings with the max thickness moved back from the traditional 30% point had lower drag in general even if they weren't laminar flow in practice.

So what gets left out of the early/small wing Tempest?
Hit this interesting "fact" about the Typhoon,
Of the first 142 delivered, only seven were not involved in serious non-combat accidents due to engine or airframe failures at one time or another.
I don't know if that is true or not and even if we take out most of the airframe failures (elevator flutter problems) The Sabre engine was far from a reliable powerplant in 1941/42.

 

[tomo pauk]

I mentioned the different profile earlier. I did not mention (my fault) the greater wing area and the change in planform which went from straight taper both front and rear to elliptical. So that makes five changes, if we want more we can look at flap area and aileron placement (better roll response?)
The broader cord is where the added wing area came from. This helped allow for the 20mm cannon to be moved back as did moving the max thickness further back on on wing.
Also means that the wing wasn't quite as thin as % number indicates and while that isn't of much concern with the aerodynamics it does make 'packaging' a bit easier. fitting the 20mm guns in without having so much barrel sticking out and not changing the wing fuel tanks (or not much). Many articles of the time called the airfoil Laminar flow and while it technically may not have been trying to correct the usage/terminally of the time a this late date may cause more confusion than clarity. I just accept that it was a terminology of the time and most everybody back then understood what they were talking about even if it actually didn't work quite they way they thought. The wings with the max thickness moved back from the traditional 30% point had lower drag in general even if they weren't laminar flow in practice.

Good points.
FWIW, I have no problems when people talk about Mustang's or Tempest's wing being laminar-flow.

So what gets left out of the early/small wing Tempest?

I have no intention to slap rails for rockets on it, like it was done wit Typhoon, and it might (and might not) be too tight for ~190 imp gals internal fuel load, as it was the case for Tempest from late 1944 on.

Of the first 142 delivered, only seven were not involved in serious non-combat accidents due to engine or airframe failures at one time or another.
I don't know if that is true or not and even if we take out most of the airframe failures (elevator flutter problems) The Sabre engine was far from a reliable powerplant in 1941/42.

Hopefully the new fighter does not have the problem of tail separation mid-air under high G load, like it was the case with Typhoons.

 

[z42]

No love for the Heston racer's original radiators? Just based on a quick look at a picture, looks pretty Mustang-like. That would leave space in the wings for fuel. If one puts the pilot in a slightly more reclined position, and a Fury-like slightly elevated cockpit for better forward visibility, then maybe space for an additional fuel tank under the cockpit? I kind of like the approach of putting the cockpit as far forward as possible, without a fuel tank between the engine and cockpit.

As for the wings, I like the Heston racer's approach with straight tapered wings, should be easier to construct. Now do the same for the tailplane too.

So we'd end up with a plane that is a bit of a hybrid between the Mustang and the Fury. But as mentioned, with the engine being such a trainwreck it's hard to envision the plane as some huge success. Maybe a better low level fighter than the Typhoon or Tempest, although without a better SC probably not competitive with Merlin or Griffon engined fighters at higher altitudes.

 

[NevadaK]

What's surprising is how small the Napier-Heston Racer actually was and how limiting that would be for the basis of a fighter, especially with the Saber engine. It is shorter than either the BF-109 or He-100 by about 5' with a comparable wingspan. Without scale giving elements in the available photographs the designs proportions make it seem much larger than it is.

 

[tomo pauk]

What's surprising is how small the Napier-Heston Racer actually was and how limiting that would be for the basis of a fighter, especially with the Saber engine.

This is why I haven't suggested that racer is a basis for a fighter, but that racer never sees the light of the day, and Heston makes a fighter instead of it.

 

[Shortround6]

There have been number of attempts to turn racing or record planes into warplanes. Some died on the drawing board/s and some made it to actual hardware and a few, heavily modified, were tried in service in small numbers, one or two were actually built in hundreds. The best results were somewhat mixed (counting the Fw 200 here as a distance record plane). The US did a sketchy design study in the early 30s with the Wedell Williams P-34 proposal and a private study was done in the book

4 large pages of performance and drag calculations for the P-34 vs the WW 44/45 racers and almost an entire chapter about the P-26 vs the WW 44. The WW 44 held the world speed record for land planes in 1933 at 305.33mph.

A certain Captain Claire Lee Chennault had even done a visit to the Wedell-Williams 'shop' to look at the latest design, the 45 with retracting gear and cantilever wing.

I know that Tomo has said that his proposal is for a 'new' plane but that leaves us very little to go on except, perhaps, a similar large fighter plane?
The Head of Engineering section of the USSAC at the time Capt. Lyons in 1934 had written Harry Williams that their airplane " would require a complete redesign to bring [it] up to the requirements for pursuit airplanes"
"By the time this had been done a great deal of time and money would have been spend and your airplane would undoubtedly suffer a great impairment in performance by the increased strength, vision, equipment, and the decrease in landing speed which would be required to make this a service airplane"

There are also some weight charts.
Some of them look a little optimistic?
like only 50lbs to make the wing go from 107.8sq ft to 151.1 sq ft?
A big problem with racers vs fighters (or even other military planes) was they were not stressed for the desired military loads. The WW proposal was stressed to 8.15 Gs ultimate and not the 12-12.5 the US was requiring for all other fighters of the time. That means it was designed for a service load of 5.43 Gs which would be unacceptable for any military.

Most other racer/record plane designs have not be looked at this extent, so this examination offers clues to look at in other planes, not absolutes. But in general, it was not case of just bolting a few guns in race plane and you are done

Note the lack of vision for the pilot.

Tomo may have a good idea about an alternative airframe for the Sabre engine. The Heston racer is not it.

 

[Shortround6]

This is why I haven't suggested that racer is a basis for a fighter, but that racer never sees the light of the day, and Heston makes a fighter instead of it.

The problem is that Heston has no real basis for fighter. How much of the racer was Heston and how much was Napier using Heston as an assembly shop I don't know.
This was pretty much like telling Cessna of the 1930s who was making these

with 145-165 radial engines to design a new plane to compete with the Mustang for the British contract, and by the way, use and engine twice as powerful as the Mustang was going to use.

NA's design expertise was somewhat limited BUT they had designed and built the O-47 observation planes, a large variety of NA-16 variants, the XB-21 medium bomber, the NA-20 prototype in competition to the Douglas DB-7 and were working on the B-25 which flew 2 month before the Mustang. Which meant they were miles ahead of either Heston or Cessna

Heston also has not production facility to speak of. They built under 10 of that nice cabin plane in the space of several years, they built 1-2 rivals to the Chipmunk trainer and another 1-2 prototypes?they built around 40-50 single engine/single seat sportplanes in the early 30s, another 1-2 prototypes?

as the Comper Aircraft company at a different location.

 

[NevadaK]

From what I've been able to find, the Napier-Heston racer was really designed by Napier. That said, Heston did make a real contribution to the war effort through the development of the photo-recon spitfire. Heston was really responsible for the advancement and conversion of the Spitfire to a long range reconnaissance platform until demand moved it back to Supermarine for larger scale production.

As for the source for another fighter, my money would be on Gloster. They seem very North American like in that they have experience with higher performance aircraft and capable of coming up with a plane that pushes the design envelope a bit.

 

[Shortround6]

From what I've been able to find, the Napier-Heston racer was really designed by Napier. That said, Heston did make a real contribution to the war effort through the development of the photo-recon spitfire. Heston was really responsible for the advancement and conversion of the Spitfire to a long range reconnaissance platform until demand moved it back to Supermarine for larger scale production.

As for the source for another fighter, my money would be on Gloster. They seem very North American like in that they have experience with higher performance aircraft and capable of coming up with a plane that pushes the design envelope a bit.

The British did a lot of sub-contacting back and forth there were a number of shadow plants that were opened that get skipped over in a lot histories (especially non-British ones).
Avro built some Blenheims and Rootes Securities built them in a new facility as just a sample. However production design is not the same as aircraft design.

I would also note that the British designers also get a lot of blame for problems that were a result of air ministry requirements. If your design does NOT meet the air ministry requirements for things like take-off and landing speeds/distances they are probably not going to buy it.
One rather famous requirement was that NO tyre could use more than 38lbs of air pressure to avoid rutting the grass airfields. This somewhat restricted the designers choice of tyre/wheel size of the aircraft depending on the weight. They could wind up using a larger/heavier wheel/tyre combo of greater diameter (or width) that was harder to fit in the plane but used lower air pressure to satisfy this 'field' requirement. Some of this stuff went away in 1939-40-41 with the changing priorities of the war and the changes/improvements to the actual airfields. Westland Whirlwind got an exemption to use 42lbs pressure in the tyres to avoid having to redesign the rear part of the engine nacelles and that was well before they even thought about sticking bombs under the wing.

British also had a problem with gun armament in 1938-39-40-41. They were asking for 20mm gunned fighters, they had the license for the 20mm Hispano gun, they were building a factory to make 20mm Hispano guns. What they didn't have in 1938-39 were actual Hispano guns, at least not more a few dozen. 1940 got bit better, not much, most went into Beaufighters with a few dozen going into a not very good installation in the Spitfire. You can draw all the pictures you want of four 20mm guns in the wings of 'fighter X' but you aren't going to many any Hispano guns until 1941 and even then in first 1/2 of the year you are going to get drum fed guns. The Belt feeds, which were not part of the original design/license didn't show up until the summer of 1940 even in drawing form.
There reasons for the Hurricane IIB and for the initial Typhoons to use twelve .303 guns and since they had drawings of a four gun Hurricane (Oerlikon guns) that go back to 1938(?) it wasn't because they hadn't thought of it yet.

Let's remember that the Wellington's big brother, the Warrick was supposed to use Sabre engines as an alterative to the Vulture. A number of British designs in 1938-39 were sketched with both engines, Most of these designs took short flights to waste bin as it became increasingly apparent that both engines were running late, had production problems and reliability problems in service.

 

[Shortround6]

Somebody has got a 5 page article from a 1943 edition of Flight magazine on line as a PDF available for down load.
I can't seem to link to it but is shows up in the image section of Google from
RCGroups

[PDF] ACo-operative Challenger

In the picture headings .

If you hit visit it wants to download the article and not let you view it.
It does have a rather good description of the radiator system including diagram/s.
While interesting it does not appear that they were going to get much actual Meredith effect out of it, of course they only had to keep the engine cool at high speed at low altitude so perhaps they could get away without a variable outlet nozzle.