Last & Best of the Piston Engine Fighter Aircraft.

[Tommy Cookers]

in the glorious 1950s when only the cream of society flew our taxpayer's BEA used (the American) Coffman starting .....
on the (Hercules) Vikings and (Centaurus) Ambassadors
the passengers of course were preconditioned with drink
electric inertia starters can also be fun - taking ages to wind up to a 20000rpm ? howl

a surprisingly interesting read ...
the historian author apparently giving alleigance to an engineering god, Hemi ...
https://www.enginehistory.org/Piston/Be ... W1AESB.pdf

it mentions eg the Sunbeam Arab procurement 'scandal' related to the deficient articulated god geometry
it also shows how many 'open liner' engines even in WW1 were working towards .....
the inevitable dethroning of the 'closed liner' engines such as the N****r L**n .....
(whose creators even years later refused their governments request for open liner design)

[J.A.W.]

in the glorious 1950s when only the cream of society flew our taxpayer's BEA used (the American) Coffman starting .....
on the (Hercules) Vikings and (Centaurus) Ambassadors
the passengers of course were preconditioned with drink
electric inertia starters can also be fun - taking ages to wind up to a 20000rpm ? howl

a surprisingly interesting read ...
the historian author apparently giving alleigance to an engineering god, Hemi ...
https://www.enginehistory.org/Piston/Be ... W1AESB.pdf

it mentions eg the Sunbeam Arab procurement 'scandal' related to the deficient articulated god geometry
it also shows how many 'open liner' engines even in WW1 were working towards .....
the inevitable dethroning of the 'closed liner' engines such as the N****r L**n .....
(whose creators even years later refused their governments request for open liner design)

The author appears to misapprehend 'hemi', as it appends to combustion chambers, including the
most efficacious placement of spark plugs, & the effects of compression-ratio/fuel grade.

He fails to mention the Napier Lion at all, which is not unexpected - since it makes the Liberty V12
he so chauvinistically eulogises - seem like a proverbial corporate camel, compared to a thoroughbred.

The record-breaking early post-war trans-Atlantic non-stop & trans-continental endurance flights
flown in the Vickers Vimy didn't use Liberty-power either, so are also to be ignored, of course.

How many Liberty-powered machines won the Schneider Trophy or took the Land Speed Record?

Certainly, no Liberty engine ever showed the Lion's ability to smoothly run at ~3 times design output,
& revving out to 4,000rpm reliably, while pushing past 400mph...

[Tommy Cookers]

.... How many Liberty-powered machines .... took the Land Speed Record?
.... Certainly, no Liberty engine ever showed the Lion's ability to smoothly run at ~3 times design output,
& revving out to 4,000rpm reliably .....

the author etc shows that WW1 aircraft engines gave more power at more rpm than their power/rpm ratings
as do modern exact reproductions
ie their 'design output' was substantially higher than their rating
eg the Merlin was allowed to use 3600 rpm (ie in a dive) when the props were fixed-pitch types

J G Parry Thomas's Liberty-engined modified Higham Special Benz 'Babs' of course took the LSR multiple times
then the White Triplex (owner J H White) powered by 3 Liberties took it once

the paired LSR Lions could be smooth at source if rigidly joined side-by-side in LSR car's natural 'handed' orientation
but that would have been too wide and too slow

both Lion and Liberty were reliable for a few minutes
the Lion had a short stroke and a short 'flat' 4 throw crankshaft - hence a big margin of available rpm
its 21% more piston area & 37% less stroke allowed it (via higher rpm giving equal piston stress) actually more power
the Lion's simple 'flat' crankshaft would have been relatively easy/cheap to improve for specially high rpm etc
and in the 1930s people eg Cobb etc had the new methanol fuel - with nitromethane coming immediately postwar

the longstroke fashion came via freakish small-engine car racing based on 'horsepower-tax' aka 'free stroke' design
this fashion wasn't entirely bad - and remember WW1 Allied fuel quality reduced with American involvement

[J.A.W.]

T-C, Napier Lion engines were reliable for more than "...a few minutes".

From beating the Italians in their own back yard flying flat-out to win the Schneider Trophy;
to flying non-stop from Britain to South Africa for 57 hrs; & averaging 134.85mph over 24hrs
at Bonneville in a Brooklands Railton driven by John Cobb..

Perhaps a good read from the Engine History collection might dispel your Lion misapprehension?

http://www.enginehistory.org/Piston/Nap ... onHx.shtml

[Tommy Cookers]

the article tells us that .......
the Lion was unable to run on the fuel in WW1 or the 20s except the postwar military fuel that included benzol(e)
not so the Liberty
initially the Lion was to be an 'overcompressed' engine unable to have full throttle at sea level

benzole was/is the waste-product of processing coal into coke (for iron smelting) or into coal gas
benzole was/is benzene, toluene, and xylene(s) - so very ' high octane'

and that .....
released for general sale in 1925 to run on fuel generally available the Lion never had more than 460 hp @ 2000 rpm
various high rpm air racing Lions were made (total only 7 engines ?)
for 1925 with 25% benzole plus 13cc TEL allowing 8:1 CR they had 680 hp
for 1927 with 'light Romanian petrol' plus 7cc TEL and 10:1 CR 900 hp @ 3300 rpm - and conspicuously 0.32 lb/hp-hr
EDIT
these dimensionally 'cut-down' but still NA of course - neither these nor supercharged Lions were ever on general sale
air ram and exhaust thrust powers would have been high at 300 mph speed and are likely part of the 900 hp figure

petrol had of course higher (mass & stoichiometric mass) -specific energy than eg benzole blends (or Avgas)
I guess they went that way to avoid accomodating increased fuel in the racing

in the 20s the Liberty was a cheap surplus unit that anyone could use
the Lion was expensive and unavailable - and it made a bigger hole in the air than did the 45 deg Liberty
the single-Lion 'open wheel' Railton car was big - and horribly heavy
not so the twin-Lion streamliner of course

the V8 Liberty would have been handy in motor sport - but it had been dropped as too vibratory for aviation
then a bit later some used the Curtiss V12

[J.A.W.]

the article tells us that .......
the Lion was unable to run on the fuel in WW1 or the 20s except the postwar military fuel that included benzol(e)
not so the Liberty
initially the Lion was to be an 'overcompressed' engine unable to have full throttle at sea level

benzole was/is the waste-product of processing coal into coke for iron smelting since 1720
benzole was/is benzene, toluene, and xylene(s) - so very ' high octane'

and that .....
released for general sale in 1925 to run on fuel generally available the Lion never had more than 460 hp @ 2000 rpm
various high rpm racing Lions were made (total only 7 engines ?)
for 1925 with 25% benzole plus 13cc TEL allowing 8:1 CR they had 680 hp
for 1927 with 'light Romanian petrol' plus 7cc TEL and 10:1 CR 900 hp @ 3300 rpm - and famously 0.32 lb/hp-hr

petrol had of course higher (mass & stoichiometric mass) -specific energy than eg benzole blends (or Avgas)
I guess they went that way to avoid race-flying increased fuel

in the 20s the Liberty was a cheap surplus unit that anyone could use
the Lion was expensive and unavailable - and it made a bigger hole in the air than did the 45 deg Liberty
the single-Lion 'open wheel' Railton car is big - and scarily heavy
not so the twin-Lion streamliner of course

Steady on now T-C, you yourself noted that British Empire sourced petrol was naturally of higher test rating
than US derived stocks, & that WW1 'throttled' engines were not designed for WOT use at sea-level...
Having noted that, the Lion proved well capable of WOT at take-off (just as the Sabre was) given decent fuel.

You cannot be serious about numbers of 'race' Lions built, since there were many iterations, from hi-comp (10-1)
N/A Schneider trophy & Brooklands/Daytona beach machines, through to mechanical & turbo-supercharged
high altitude engines.

The 45 degree Liberty was naturally vibration-wracked, & was (unlike the Lion) also not presented with finely
streamline-cowled aerodynamics, both Liberty-powered 'Babs' & 'Triplex Special' LSR cars killed their drivers.

The Liberty was obsolescent/over-produced as a result of Ford corporate power, & the very effective Lion
was on the British 'not for sale to foreign military' list for years.

When it was cleared, Junkers evidently took a close interest & utilized Lion-tech In exchange for their 2-stroke..

[Tommy Cookers]

.. you yourself noted that British Empire sourced petrol was naturally of higher test rating than US derived stocks, & that WW1 'throttled' engines were not designed for WOT use at sea-level...
.......The 45 degree Liberty was naturally vibration-wracked .....
.... Junkers ..... utilized Lion-tech In exchange for their 2-stroke..

Dutch Empire fuel (naturally high in aromatics ie benzene etc) - no official testing, that hadn't been invented
the problem grew as US-sourced fuel useage increased anyway - long before US interest (in strategic bombing - or war)
www.theaerodrome.com/forum/showthread.php?t=45364 is priceless
no British service engine was 'throttled TO' design (before supercharging came of course)
reduced CR pistons were widely introduced c.1917- we now know McCudden ? etc kept using old CR etc for altitude

the 45 degree Liberty V12 had no vibration - that's why they make V12s
the instantaneous sum of piston etc inertial forces and moments always being zero - for any bank angle
yes the crankshaft was stiffened etc and any of the original type kept US-only
of course all engines have some inconsistency of combustion

I don't see where/how Junkers used Lion ideas

[J.A.W.]

.. you yourself noted that British Empire sourced petrol was naturally of higher test rating than US derived stocks, & that WW1 'throttled' engines were not designed for WOT use at sea-level...
.......The 45 degree Liberty was naturally vibration-wracked .....
.... Junkers ..... utilized Lion-tech In exchange for their 2-stroke..

Dutch Empire fuel (naturally high in aromatics ie benzene etc) - no testing, it hadn't been invented
the problem grew as US-sourced fuel useage increased anyway - long before US interest (in strategic bombing - or war)
www.theaerodrome.com/forum/showthread.php?t=45364
no British service engine was 'throttled TO' design
but reduced CR pistons were widely introduced c.1917- we now know McCudden ? etc kept using old CR etc for altitude

the 45 degree Liberty V12 had no vibration - that's V12s
the instantaneous sum of piston etc inertial forces and moments being zero - for any bank angle
yes the crankshaft was stiffened etc and the original type kept US-only

I don't see where/how Junkers used Lion ideas

No T-C, the Liberty's 45 degree angle certainly disposed it to suffer from torsional vibration,
esp' in the V12 with its uneven firing order, & long 'ropy' crankshaft. Sure it gave fair warning
to pilots not to exceed its very modest rpm range, by incipient threats to leap its mounts, or
disgorge its prop, but no way known was it going to hack high-pressures/high rpm like a Lion.
(Did you miss the section dealing with original Lion development as a throttled T.O. engine?)

The Nuffield built Liberty tank mills, in 'governed' form, still fatigue-damaged their accessory
drives, spat out major gaskets, & if 'fettled' to run freely - broke all manner of drive-train
componentry from crankshaft to final drives...

See analysis here: http://enginehistory.org/Piston/Before1 ... nalVib.pdf

The Lion had crankshaft end-feed lubrication, & oil-jet spray to piston undersurfaces & that's
a couple of features (cam support/drives also) which Junkers-Jumo put into their new 211/213s,
(It took R/R about a decade to fit such a crankshaft end oil-feed to their Merlin).

[Tommy Cookers]

No T-C, the Liberty's 45 degree angle certainly disposed it to suffer from torsional vibration,
esp' in the V12 with its uneven firing order, & long 'ropy' crankshaft. Sure it gave fair warning .....

the Liberty didn't 'suffer' from torsional vibration (so nor did its operators)
all multi-cylinder crankshafts have significant level of stress driven by their natural torsional oscillations .....
these are significant only at very high frequencies and are (obviously) unrestrained by the bearings
so the users and the vehicle are isolated from and insensitive to these
the designer keeps the stresses low enough for acceptable crankshaft life - without excess weight and bearing friction
the Liberty's designers did this - but it took 2 attempts
no overseas Liberty ever broke a crankshaft
yes metal propellers replacing wooden ones (in later years) could have reintroduced the problem

in respect of the vibrations which are readily predictable and to which the users and the vehicles aren't sensitive .....
the Liberty (like any V12) was benign - and the Lion (like any flat-cranker with non-flat bank alignments) wasn't
(btw the Liberty V8's vibration looks somewhat better than the Lion's)


I flew numerous hours with 1970s RR-enlarged 130 hp Continental 100 hp engines ... they were perfectly 'smooth' .....
but had an undiscovered torsional vibration problem (undiscovered because users weren't sensitive to it)
after a few hundred flying hours this problem sometimes caused the propeller to break away in flight ....
RR suddenly stopped selling the engines

[J.A.W.]

Did you read the study linked in my previous post T-C?

Seems that you've somehow missed the quote included from a British analysis, where it is stated:
"an epidemic" of crankshaft failures happened, right at the crucial torsional/rpm node..

Why was the 45 degree angle V12 not repeated in any subsequent V12s built for hard running,
if it was indeed, per your 'bold claim' - "Benign" - in its rotational/reciprocal attributes?

Do you really imagine that gyrations of the kind which warped the crankcase fixings & squeezed
out gaskets like pastry, as an ominous portent of yet greater crank rope-trick contortion-based
horrors to come were missed by the British engineers working on getting their tanks to run well?

Why do you think the Nuffield Liberty was 'put out to pasture' & replaced by a de-rated R/R Merlin,
~1/2 way through the war?

[Tommy Cookers]

Did you read the study linked in my previous post T-C?
Seems that you've somehow missed the quote included from a British analysis ..
Why was the 45 degree angle V12 not repeated in any subsequent V12s built for hard running,

Yes I am familiar with Mr Raymond's study (this person that you rubbish when he's criticising sleeve valve engines)

the study doesn't forecast crankshaft failure - only the rpm(s) at which prolonged running might contribute to failure
'resonance' only means increased (above notional 'forced' vibration) - not necessarily a dangerous level of vibration
R acknowleges this when reminded that only the early version (service within the US) had a real problem
... the 'epidemic of failures' that he 'quotes' from a paper that you haven't seen (on work starting with early Liberties)

for the same reason eg modern top-selling aircraft engines have some ranges of rpm that are impermissible
this is the designer's work (and part of the pilot's legal obligations to comply)
remember flying requires only a few combinations power and rpm (unlike car or truck operation)

we can say that Napier introduced this supposedly dangerous vibration c.1904 (with the 6 cylinder car)
they bluffed their through the situation - calling it 'power rattle'
'Steady' Barker's car was driven hard over 40 years without a breakage
see this https://www.motorsportmagazine.com/arch ... -july-1982
https://www.motorsportmagazine.com/arch ... ion-ethics
https://historicvehicles.com.au/histori ... ds/napier/

the Liberty was the first to fly the Atlantic - and the first to fly round the world
produced in far greater numbers (with various crankshafts and developments) and for longer then the Lion
(Ford made 433000 cylinders - enough for c.35000 engines)
c.1932 the Tank Corps refused the RAF's entire stock of Lions at £5

the potential benefits of 45 deg of course reduced as engines got smaller (less stroke) and aircraft got bigger
and Raymond does say that Vincent wasn't entirely wrong

[J.A.W.]

Did you read the study linked in my previous post T-C?
Seems that you've somehow missed the quote included from a British analysis ..
Why was the 45 degree angle V12 not repeated in any subsequent V12s built for hard running,

Yes I am familiar with Mr Raymond's study (this person that you rubbish when he's criticising sleeve valve engines)

the study doesn't forecast crankshaft failure - only the rpm(s) at which prolonged running might contribute to failure
'resonance' only means increased (above notional 'forced' vibration) - not necessarily a dangerous level of vibration
R acknowleges this when reminded that only the early version (service within the US) had a real problem
... the 'epidemic of failures' that he 'quotes' from a paper that you haven't seen (on work starting with early Liberties)

for the same reason eg modern top-selling aircraft engines have some ranges of rpm that are impermissible
this is the designer's work (and part of the pilot's legal obligations to comply)
remember flying requires only a few combinations power and rpm (unlike car or truck operation)

we can say that Napier introduced this supposedly dangerous vibration c.1904 (with the 6 cylinder car)
they bluffed their through the situation - calling it 'power rattle'
'Steady' Barker's car was driven hard over 40 years without a breakage
see this https://www.motorsportmagazine.com/arch ... -july-1982
https://www.motorsportmagazine.com/arch ... ion-ethics
https://historicvehicles.com.au/histori ... ds/napier/

the Liberty was the first to fly the Atlantic - and the first to fly round the world
produced in far greater numbers (with various crankshafts and developments) and for longer then the Lion
(Ford made 433000 cylinders - enough for c.35000 engines)
c.1932 the Tank Corps refused the RAF's entire stock of Lions at £5

the potential benefits of 45 deg of course reduced as engines got smaller (less stroke) and aircraft got bigger
and Raymond does say that Vincent wasn't entirely wrong

T-C, why do you imagine that by critiquing Raymond on sound technical grounds, I "...Rubbish" him?
I noted the finding in a period British report in Raymond's Liberty analysis & quoted it as he had..


As for the USN's Curtiss NC4 trans-Atlantic flight, it seems you somehow forgot to include a few salient
matters of fact, including propeller/engine failures (only one made it from four aircraft involved,
on a several stop protracted period journey).

Similarly, the Douglas World Cruiser flight knew in advance the limitations of their Liberty V12s
& had liberal logistics laid-on in advance of replacement engines/props etc...

As for the Lion being offered by the RAF to the Tank Corps in 1935, you can bet they were later glad
that no British tank then built/under design could accommodate it, since it meant that those 'surplus'
Lions would be available as core units for marine conversion & power RAF air-sea rescue speedboats.

However, do feel free to do a search for the reports on problems with the Liberty as a tank mill...

[johnny comelately]

a slightly hybridised post:
Whenever in a million years will electric motors be this fascinating and 2.5 micron what?

[Stu]

a slightly hybridised post:
Whenever in a million years will electric motors be this fascinating and 2.5 micron what?

The second one in the clip (the P&W 4-row radial “4630”?) is an absolute beast! Sounds fantastic

[johnny comelately]

2001 flying backwards biplane (which has been used to fight!)
The An-2 has no stall speed, a fact which is quoted in the operating handbook. A note from the pilot's handbook reads: "If the engine quits in instrument conditions or at night, the pilot should pull the control column full aft and keep the wings level. The leading-edge slats will snap out at about 64 km/h (40 mph) and when the airplane slows to a forward speed of about 40 km/h (25 mph), the airplane will sink at about a parachute descent rate until the aircraft hits the ground.
As such, pilots of the An-2 have stated that they are capable of flying the aircraft in full control at 48 km/h (30 mph) (as a contrast, a Cessna four-seater light aircraft has a stall speed of around 80 km/h (50 mph)).[citation needed] This slow stall speed makes it possible for the aircraft to fly backwards relative to the ground: if the aircraft is pointed into a headwind of roughly 56 km/h (35 mph), it will travel backwards at 8 km/h (5 mph) whilst under full control
From this, what was the starting system?
A questionable BSFC of 182 g/kw/h ??
https://en.wikipedia.org/wiki/Antonov_A ... ons_(An-2)