MOST UNDERRATED AIRCRAFT OF WWII?

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What on earth does "Jet bent" mean? By 1950 the airspeed record was 600 MPH a speed impossible for piston engine aircraft even today, there was no conspiracy against the Sabre or Centaurus the world had moved on.
 
I beg to differ because I read a lot of his ramblings. For a motorcycle to have its CoG below the wheel axles it would have no ground clearance at all and a wheelbase as long as a house with large diameter wheels, even drag racers don't come close, it was complete B/S, I and many others couldn't figure out how he got paid, in a short time he didn't.
 

Again, this goes to the fact that some engine attributes suit different roles better, Setright made the point that the Sabre was a real 'fighter' engine, & comments from those who flew it in combat - confirm this, as Kiwis like Ron Dennis, who shot down an Me 262 - after pursuing it flat out for 50 miles wrote:

"It loved tough handling,& never objected to extended periods at max boost & rpm.."

&, 122 Wingco ( & top RNZAF ace) E.D. Mackie who wrote,

"The harder you flew it, the better it went".

Biff can confirm that even today, fighter jocks appreciate an engine that will respond 'stat',
when throttle commands are given..

Len Setright wrote that the Sabre "could be blipped up & down the rev-meter like a car engine",
which is something the big radials - did not take well to.

The fact is - the Sabre was a victim of circumstances, being subject to 1/2 arsed Brit manufacture methods
meant that only 5,000 odd were built, & were really only on-stream when piston engines were eclipsed by
turbines for future fighters.

Never-the-less, every well-built Sabre fitted to an in-service warplane in WW2, made a 'top-flite' contribution,
which is more than can be said for the Merlin, many of which went into really - pretty useless planes..
 
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pbehn said:
What on earth does "Jet bent" mean? By 1950 the airspeed record was 600 MPH a speed impossible for piston engine aircraft even today, there was no conspiracy against the Sabre or Centaurus the world had moved on.
Click to expand...

WW2?
What was the Meteor's contribution? A dozen V1's?
& by 1950, it too - was well past its 'best by date'.

Being 'Jet bent' is self evident, surely..

The RAF & USAAF jumped on that 'bandwagon' real quick, but the 1st gen jets - just weren't that good..

Old F-51 & F-82 Mustangs had to be spurred back into duty in 1950, for the fighting in Korea,
because the F-80 was too short-legged..
 
J.A.W. said:
Never-the-less, every well-built Sabre fitted to an in-service warplane in WW2, made a 'top-flite' contribution,
which is more than can be said for the Merlin, many of which went into really - pretty useless planes..
Click to expand...
This is simply flaming a forum, I thought that died out years ago. I will use the ignore function. Below is a list of A/C with Merlin engines.

 

Nevermind that, check this.. a Len Setright book.

Some Unusual Engines

Members can see for themselves, the technical grasp Setright could & did, muster..
 
pbehn said:
This is simply flaming a forum, I thought that died out years ago. I will use the ignore function. Below is a list of A/C with Merlin engines.
Click to expand...

Check the hostile tone can you, ben - as fairly asked, by moderation.

In 1944 Lancaster/Mosquito/Mustang were 1st rate service aircraft flying with Merlin power,
& yet hopelessly outdated Hurricanes were still being mass-produced.. a waste of a Merlin, surely..
 
Seems the venerable Napier Lion is perhaps a tad 'under-rated' too,
actually, it is fairly remarkable for a century old ( yes, 100 years!) mill.

DOHC 4V, oversquare with slipper pistons & sophisticated crank-end pressure lubrication.


 
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The tough ol' beast pictured in the post above was able to hack supercharger pressures
high enough to add ~1000hp to its original 450hp output, & wrest back the World Land-speed Record
from R-R's mighty R-type engine, & hack being hammered across the salt at nearly 400mph,
a record that wasn't bested 'til the `60s..





& the Lion's designer Rowledge, working for R-R, had to replace the typically flimsy*
R-R 'knife & fork' conrods in the early R-type mills, with a Lion-wise ( but only 2 banks, of course)
'master-slave' set-up, to enable the 36 litre R-type to keep running hard..

Did the Junkers Jumo 222 designers have a Lion & Lioness** on hand, & decide to mate them?

*It took R-R about ten years to put a crank-end lubrication feed system on the Merlin, & add
heavy duty conrods, but nowadays for Merlin users who run them real hard, Allison rods
are a 'must do' durability mod.

**Lioness was an inverted Lion, & Lion + Lioness - come quite close dimension-wise to the Jumo 222.
 
Bet ol' 'Pinkie' Stark had an 'interview' with the C.O., after using the expensive 14ft prop of his Typhoon
to 'play bloody arborist' in France & bring it back all scuffed up..



What do you reckon he told the 'boss'?
"Relax Skipper, shit'll buff out..."
 
J.A.W. said:
Nevermind that, check this.. a Len Setright book.

Some Unusual Engines

Members can see for themselves, the technical grasp Setright could & did, muster..
Click to expand...
Thanks for the link, I'll look the Chrysler Multibank part when I have spare time. Unfortunately it seems that Setright doesn't deal with the other two unusual engines I'm intrerested in, Fairey P.24 and RR Crecy, but of course they were not production engines and Crecy's story advanced only to bench test stage.

Juha
 
Quite a few engine makers used fork-and-blade (not "knife-and-fork") connecting rods; the alternative articulated connecting rods have several disadvantages, including increased problems with vibration, and, as happened in several quite successful engines, different strokes in the two banks. Both Allison and Rolls-Royce used these; Daimler used articulated rods. Neither is "better"; Rolls-Royce used articulated rods in their various "X" engines, but Allison used paired fork-and-blade rods in their XH-4520.

The Allison V-1710 had a very good mechanical design; its performance shortcomings seem to have been more due to poor supercharger design and integration than anything else. There was, as an aside, a prototype turbo-compounded V-1710 that was to have a military rating of 2,320 hp and a war emergency rating of 3,090 hp.
 
Can we please stop with the pissing contest?


1913 Peugeot Grand Prix car engine. DOHC 4 valves per cylinder. Well angled valves.
Much copied between 1913 and 1918. Any engine designer worth his T square knew about DOHCs and 4 valves per cylinder in the early 20s.

Design "features" were often compromises due to space, weight, materials (early valve springs were crap and had a high failure rate), manufacturing techniques/abilities (British radial engines went to forged cylinder heads before the US radial makers because British casting techniques weren't as good. They couldn't get the quality heads they wanted at an acceptable scrap rate by casting.)

Without know why a designer did something we are guessing and making some rather large assumptions.

6 bank engines don't have to be two 3 bank engines smushed together on a common crankshaft. They can start as short 12 cylinder engines.

The 20s and 30s saw a considerable number of engine layouts. Some of them just showed later designers what NOT to do.
 
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I didn't recall anything but going through the index eventually found something p. 348 "Reluctant to become wholly dependant on the Sabre version, the front fuselage of a Tornado was lengthened, given the tail and wings of a Typhoon, and fitted with a Centaurus. It flew fo0r the first time on23 Oct 41, but was 10mph slower than a Typhoon. Given a later engine and a four-bladed propeller it eventually achieved 430mph. But whilst the nose of a standard Typhoon airframe was too short for a radial engine, the long-nosed Sabre Tempest airframe was able to accept one with little modification, and, likely to be faster and handle better than the Typhoon. Freeman had ordered two Tempest airframes in Nov 41, and early in 42, he stopped work on six modified Centaurus-Typhoon airframes, and ordered four more Tempest prototypes, two with Centaurus and two with Griffon engines." Note: "The Griffon Tempests were cancelled, probably because of installation problems; the Griffon was at least 600 lb lighter than the Sabre or the Centaurus."
 
The proposed Griffon-Tempest prototype, the putative 'Mk III' was completed as a Fury, LA 610,
& flew with a Griffon, equpped with an R-R annular radiator, & Rotol contra-props,
but it proved to have the lowest performance of the Fury prototypes, ( until re-powered with a Sabre, that is).

'Officially' the demand for the low-production Griffon to fit into Spitfires was cited as the reason as to why no further
Griffon-Furies were built, yet although the Griffon was produced as intended for 'Naval' applications, & was in
FAA service at sea in Fireflies & Seafires, the Sea Fury was powered by the big Centaurus.

Obviously the performance aspect outweighed the logistics/engine commonality argument.


@ SR6, ta for posting those interesting engines, they serve to demonstrate that Napier
(they'd raced their own cars), saw Grand Prix racing engines as an aiming point - for their aero-engine tech.

& by contrast, all of those odd-ball 'radialine' & X-type mills built - turned out to be 'pissing in the wind' exercises.

Roy Fedden had equipped Bristol radials with 4V 'pent roof' combustion-chamber poppet valve heads, but found them less efficient than the sleeve valve, which he persevered with.
 
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SR6, the 5 years between the DOHC 4V Peugeot & Napier designs - is indicative of how fast things
were progressing under the impetus of war.

From radically undersquare B X S ( the small bore dictated those angles - for the race-sized valves to fit & flow),
to moderately oversquare - & from long-skirt Fe pistons to Al slipper-type, with lube jet underside cooling..

Curiously, Cosworth design, who'd adopted the narrow angle pent-roof 4V poppet valve set-up,
( as used in the WW 2 Allison V12)& raced it so successfully in a V8 F1 engine, went on to build
a sleeve-valve unit - which, just as the aero-engines had, demonstrated its superior port/time/area,
& other attributes - as a G.P. race mill - & which of course, was then promptly banned, by the FIA...
 
I would note that the Germans used a number of 4 valve aircraft engines in WW I with valves being actuated by several methods.
Some of the 4 valve heads had splayed valves (Pent roof?) some did not.
Point is that Rowledge/Napier invented very little. They may have combined more examples of"best practice" than many other engines of the day in one engine.
A lot of these engines were designed to get around known limitations. For example the DOHC design does not give you extra power in and of itself. It does allow for "better control" of the valves at higher rpm. That is to say it is less subject to valve "float", that is valves not following the cam profiles at high rpm due to the springs not being strong enough to yank them shut against the inertia of the rest of the valve train, the rocker arms and long push rods.
Now if your engine isn't operating at an RPM that runs into such problems using a DOHC design head only adds weight and expense to the engine.

At any given point in time the RPM limit of the valve train was usually governed by the quality/technology of the valve springs.
RPM limit of the engine could also be governed by the strength of the bottom end (

The Lion was a high RPM engine for it's time and one of it's trade offs was that the short 4 throw crankshaft was lighter and had less flex than the longer V12 (or straight 6-8) engines. Against this was the extra width of the engine and the need of a 3rd cam drive set up and the two extra camshafts.
Quite a few of these engines used pressurized oil running from the crankshaft mains to the rod bearings though passages in the crankshaft, from there little tubes ran through the connecting rods taking the oil from the rod bearing to the "little" end bearing (gudgeon or piston pin). How much excess flow there was I have no idea.



Some of these old engines were both sophisticated and crude at the same time. For example in some of the German WW I engines the intake and exhaust valves were interchangeable. Great from a manufacturing, supply and mechanics point of view but perhaps not so hot for performance?
Of course there were no high temp steel alloys, let alone sodium cooled valves, at the time so the use of the same alloy was more necessity than what might have been desired. Please remember they were still arguing over whether aluminium or cast iron was better for pistons.

A lot of times the valve springs were exposed to the open air for cooling. Of course this doesn't do much for the valve stem and the valve guide to have dirt, dust and grit being blown on them continually.

It is this "market" that the Sleeve valve engine started development.

I would also question Feddens use of the "pent roof" combustion chamber. Yes he used 4 valves placed in two rows with an angle between the rows. however they then placed the spark plugs on the very edge of the combustion chamber, outboard of the valves and instead of a cross flow head (intake and exhausts on opposite sides of the chamber) they had one intake and one exhaust valve in each bank. I have no idea if this helped or hurt.
In any case there are two differences from what modern performance enthusiasts think of as a Pent roof chamber.

The radial sleeve valve engines were a big improvement over the Bristol and Armstrong Siddeley radials but that is damning with faint praise as those engines were far from the forefront of engine technology in the late 30s.
 
By far it's the P-38 Lightning! The Lightning defeated both the Japanese and the Luftwaffe before the more publisized cleanup crew showed up.

In the West and the Pacific it fought the best the Japanese and Germans had to offer and defeated both. The pilots who flew the Fork Tailed Devil in 1942 - 43 were constantly out numbered and were fighting the best of the best. By the time the P-51 and the F6F came along it was all over both in terms of numbers and quality of opponents.

The Mustang and Hellc at fought the dregs of the Luftwaffe and Japanese Army and Navy.

"By the time Mustang numbers built up in the ETO, the Luftwaffe had already crossed the knee in the Lanchesterian attrition war curve and defeat was inevitable. While the much admired P-51 made a critical contribution, it is worth noting that cumulative deployments of the Merlin powered P-51 matched the P-38 only as late as the end of 1944, which is clearly at odds with the established mythology. With the 8th AF, the long range escort load was shared equally by the P-38 and P-51 throughout the decisive first half of 1944."
 

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@ SR6, You are correct about the poor reputation of the Bristol poppet valve gear,
which AFAIR, were lampooned with remarks along the lines of:

'Bristol fuel economy is good, but any savings made, are quickly lost again - on valve-jobs!'

As for DOHC, this was a way ( albeit a costly way) of getting good geometry (valve guide wear-wise),
& reducing wear at the cam/valve interface.

R-R Merlins have a bad reputation for chewing up cam-followers, with this fault not limited to
( but certainly exacerbated by) high-boost applications wherein the valve has to overcome the
increased pressures to open/close, since it was remarked upon in N/A usage, as a tank mill, too.

On the ports/manifolding layout vs combustion-chamber valve array issue, the Hispano derived Klimov's
had some odd permutations too, but other than for heat flow-path concerns, as long as the manifolds & ports
themselves are not restrictive - or so bulky they affect frontal area, they are irrelevant to combustion itself.
 
J.A.W. said:
Roy Fedden had equipped Bristol radials with 4V 'pent roof' combustion-chamber poppet valve heads, but found them less efficient than the sleeve valve, which he persevered with.
Click to expand...

The old Jupiters use 4 valves but the valves were parallel in a "flat head". However the type of construction ws less than ideal

Cylinder on the right was made of steel and was a closed tube with the valve seats integral with the cylinder. The "head" on the left was a cap that fit on top and due to the difference in expansion under heat of steel and aluminum there was always a thin gap between the two which hindered cooling.
Number of valves is not the only criteria for engine breathing, size of of valves, lift of the valves, and the size/shape of the ports also come into play as does the intake and exhaust systems.

I would note that the Bristol did NOT introduce the pent roof heads into production until 2-3 years after they started working on sleeve valves.
The Pent roof heads went on open barrel cylinders and the valve seats were inlet into the aluminum (sometimes cast but soon forged ) heads.

I would also note that American radials also made many changes over the years and between models as they strove for more power.
For example, Wright, on the R-1820 not only changed crankcases between the G-100 series and the G-200 which allowed for higher rpm ( engines went from 1100hp to 1200hp) but the cylinder heads were different with the G-200 heads having bigger intake ports for better breathing. There were many other differences including more finning for better cooling, the main limit to high power in air cooled engines. It doesn't matter how much fuel/air you can stuff in the engine if the engine goes into meltdown mode in a matter of seconds.



Picking one or two features and saying "ah ha, this engine is better because......" may or may not be true because we know so little of all the other details.

Then you get into arguments as to whether a 4 valve head offers better cooling to the small valves than a 2 valve head does to it's larger valves or whether the 2 valve head and it's simpler valve gear offers more fin area/better cooling the head as a whole.

I would note the war time Hercules engines never seemed to offer any real advantages in boost used or power developed over the American radials.
 
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