Last & Best of the Piston Engine Fighter Aircraft.

[J.A.W.]

http://www.wwiiaircraftperformance.org/ ... ornet.html
proves that ....
look at Supplemental (list of items) ....
(item Merlin 130...Operating Warning Card)
the Hornet was on 100/130 initially limited to 18 lb boost - but this was raised to 20 lb
(item Hornet Pilot's Notes - Operating Data)
the Sea Hornet was (being always on 100/130) limited to 20 lb ..... and .....
(item Sea Hornet MkXX&XXI Leading Particulars)
so gave 1960 hp at 4000' ..... and of course other powers at other altitudes
ie 2030 hp widely stated eg by (former head of experimental flying) ace pilot Brown isn't inconsistent with the above

(btw the performance chart suggests that Max Combat power gave 50 mph more speed than Rated power)

an engine rating is a boost rating - not a power rating ....
for a given boost..... supercharger power consumption will vary with altitude and with (auto) throttling
so crankshaft power (within a given rating) will be different for every different altitude
(so many apparently different rated 'powers' - this usually concealed on charts as being a pointless complication)

It appears T-C, that you may be confusing an engine's 'type-tested' official horsepower 'rating'..

(It is indeed a horsepower figure, just as specifically defined in Wilkinson's book - albeit yes,
with output dependent on 'settings' levels as may be deemed 'permissible', in various operating
circumstances, & of course including fuel/boost/ADI/rpm/altitude/time-limit - particulars)

..with inflight instrumented engine 'operating data', as are listed under 'principal engine limitations'
in 'Pilot's Notes'...

It is worth checking the 'Service approval' letter in those Hornet 'supplemental' pages you linked,
as it specifically refers to 'Service Type tests' as an official source of 'ratings', from which 'limitations'
on permissible usage by pilots (& visible for them to monitor, in cockpit), are then delineated.


That the pilot of a Sabre-Tempest F6 could enjoy that 2165hp 'normal setting' (available for as long
as the fuel aboard allows) at a similar height to a Merlin making under 2,000hp (for 5mins max),
on 100/130 avgas, shows to advantage what Tempest units had in hand for pursuit of fast targets
such as V1 cruise missiles, 'rat catching' of Nazi jets, & even for realistic A2A training of RAF jets..

[Tommy Cookers]

to put some flesh on the dry bones of the usual eg 'V-1710-39 rated at 1150 hp @ 11800ft'/1200 hp @ SL stuff .....
(the -39 engine in P-51As and P40Ds & Es and the -73 in P-40Ks)

'Service Use of Higher Power Outputs on Allison V-1710 Engines'
(letter from Chief Engineer R M Hazen to USAAC Material Center Dec 12 1942) - said ....

F3R (USAAC -39) & F4R (-73) (8.8:1 s/c gear) had for months WEP 60" raised to 66" 18lb boost - Middle East and Australia
60" giving 1570 hp @ 3000 rpm - and 66" giving 1745 hp @ s/l and 1770 hp @ 2000' - amendment 5 (100 ON?) fuel reqd
and 70" 20 lb sustained was reported in Australian theater
air ramming (from speed at low altitudes) and/or over-revving is necessary to obtain 66" or 70"
(and we know now that RAF Mustangs used over 70" over France in 1942)

given the introduction of E18 & E19 engines (USAAC -85 -81) (9.6:1 s/c gear) (with 57" WEP) .....
these engines MAP would be much more responsive to air-ram and to over-revving .....
so their viability in higher MAP use should not be assumed

NB - these had AUTOMATIC BOOST CONTROL - but rated 1200 hp@ SL 1125 hp @ 14600' - P-40M/N/R and P-39M/N/Q
NB - presumably this auto 57" could be escaped by going beyond the (throttle) gate as per British engines eg Merlin
NB - does the Merlin (or these Allisons) 'through the gate' go into a higher auto boost realm - or is it unregulated ?
(and presumably going beyond the throttle gate is necessary or useful above full throttle height)


everyone and his dog gives the Sea Hornet 'rating' as 2030 hp on 18 lb boost (though we've proof of 20 lb on 100/130)
and can see the first Hornet Operating Warning card saying (for 100/130) set throttle 'detent' to 18 lb
18 lb would have been exceeded by going through the gate/beyond the detent set (this of course being notifiable)
so presumably the Sea Hornet did exceed its rated 2030 hp when 'beyond the gate' aka in RNspeak 'Max Combat'



the simulator players seem to have some useful information ....... eg ....

air-ram seemed to increase usefully the full throttle height eg of the LF Spitfire 9 &16
(having RM10SM aka 66/266 Merlin - RM9SM should have had even more power at low altitude)
so much so that the USSR even postwar used the LF as its high-altitude defence

some units fitted latching high gear 'test' switches (manual over-ride of auto so a formation could all get HS together)
(by this means at low altitude 97" was reported by one P-51D user escaping the enemy)


(I wonder) ....
when (if ever) did 'we' factor ram into power and performance predictions ?
we hid the exhaust thrust (except to benefit turboprops)

[J.A.W.]

to put some flesh on the dry bones of the usual eg 'V-1710-39 rated at 1275 hp @ 7500ft' stuff .....

'Service Use of Higher Power Outputs on Allison V-1710 Engines'
(letter from Chief Engineer R M Hazen to USAAC Material Center Dec 12 1942) - said ....

F3R (USAAC -39) & F4R (-73) (8.8:1 s/c gear) had for months WEP 60" raised to 66" 18lb boost - Middle East and Australia
60" giving 1570 hp @ 3000 rpm - and 66" giving 1745 hp @ s/l and 1770 hp @ 2000' (amendment 5 fuel required)
and 70" 20 lb sustained was reported in Australian theater
air ramming (from speed at low altitudes) and/or over-revving is necessary to obtain 70" (or 66")
(and we know now that RAF Mustangs used over 70" patrolling over France in 1942)

given the introduction of E18 & E19 engines (USAAC -88 -85 -81) (9.6:1 s/c gear) (with 57" WEP) .....
these engines MAP would be much more responsive to air-ram and to over-revving .....
so their viability in higher MAP use should not be assumed


the simulator players seem to have some useful information ....... eg ....

air-ram seemed to increase usefully the full throttle height eg of the LF Spitfire 9 &16
(having RM10SM aka 66/266 Merlin - RM9SM should have had even more power at low altitude)
so much so that the USSR postwar used the LF as its high-altitude defence

some units fitted latching high gear 'test' switches (manual over-ride of auto so a formation could all get HS together)

(I wonder) ....
when (if ever) did 'we' factor ram into power and performance predictions ?
we hid the exhaust thrust (except to benefit turboprops)

The Soviet forces also appreciated the Allison's tolerance of over-boosting in their L-L
Bell Airacobras which uniquely suited their uses, being short low/medium level sorties.

As to ram effects, the sophisticated E-E 'engine house' constructed for Napier to 'bench'
develop the Sabre not only offered a 400mph fan-ram, but also electric-brake dyno's
which fed the power produced on test, back into the local town-supply power grid...

[Tommy Cookers]

As to ram effects, the sophisticated E-E 'engine house' constructed for Napier to 'bench'
develop the Sabre not only offered a 400mph fan-ram, but also electric-brake dyno's
which fed the power produced on test, back into the local town-supply power grid...

RR used 2 Kestrels to give the 400 mph air-blast to their Schneider Trophy engines 'on the bench' in 1929/31
if the Italians had used this (for proper carburation) they would have saved planes and lives and won the S.T. in 1931
(instead of having in-flight explosions in their 24 cylinder supercharged induction system)
https://oldmachinepress.com/2012/10/14/ ... the-mc-72/

the British fighters in 1940 had a notional Full Throttle Height of 14750'
clearly their real-world FTH was higher - due to 'free supercharging' from air-ramming
the (early) Allison FTH was 11600' - not wildly different/inferior

presumably flight conditions weren't simulated in bench tests that 'certified' engines and engine power
I don't know whether such a system was ever brought in
ie what was the eg Napier's measured power ? - engine power without ramming effect or engine power with it ?
and Rolls-Royce's ?


btw
a 'new' Yak-3 was advertised at $425000 - but a P-82 at $12000000
the book says the Yak lands in 545 m but a display pilot refuses to operate with less than 1200 m
also the P-82 aka F-82 could have 'out-Tempested' the Tempest (if it had gone for that role ie first FTH at only 2250')
the 82 was to have 120" Merlins but the ptb refused to pay the $6000 licence fee that RR asked Packard (post VJ day)

btw 2
Wilkinson's 'bible' has misquoted more Sabre powers (than existed in the real engines that that book shows)
3000 hp at SL doesn't exist (this claimed without ADI !) on the actual 3055 hp ADI @ 2250' engine
(Flights plots - throttling loss and iirc because the 17.25 lb boost isn't available at SL)
a reminder - Raymond's 'anti-sleeve' article says sleeve (wall ports) waste engine length (and so waste weight) ....
the reason the Sabre has 2 crankshafts and crankcases ?

[J.A.W.]

As to ram effects, the sophisticated E-E 'engine house' constructed for Napier to 'bench'
develop the Sabre not only offered a 400mph fan-ram, but also electric-brake dyno's
which fed the power produced on test, back into the local town-supply power grid...

RR used 2 Kestrels to give the 400 mph air-blast to their Schneider Trophy engines 'on the bench' in 1929/31
if the Italians had used this (for proper carburation) they would have saved planes and lives and won the S.T. in 1931
(instead of having in-flight explosions in their 24 cylinder supercharged induction system)

the British fighters in 1940 had a notional Full Throttle Height of 14750'
clearly their real-world FTH was higher - due to 'free supercharging' from air-ramming

presumably flight conditions weren't simulated in bench tests for performance quantification eg 'rated power'
I don't know when this system was brought in (if it ever was)
unless eg Napier were to give a measured power higher than they would have measured without ramming effect

This US test of the final production variant P-47N (linked below)provides a salient report on the
reality of running WEP (war emergency power) engine settings, & why the 'engine limitations' of
so many high performance combat types - while acceptable under the duress of wartime ops when
fettled/maintained as required - were cut back in peacetime, as budgetary protocols intruded.

(As the test shows, on WEP at FTH, the big 'Jug' only adds ~30mph, so the chances of the Soviet
high-altitude air-defence then vectoring an intercept plot for their L-L P-47s to catch an RAF PRU
Spitfire 19 snooping over the 'red' side of the 'iron curtain' successfully were next to nil. Not that
the RAF's own new-fangled Meteor jets could do it either - on exercise trials - for that matter).

The official acceptance type-test ratings were duly capped by 'engine limitations' accordingly:

http://www.wwiiaircraftperformance.org/ ... 88406.html

[J.A.W.]

T-C, as far as ram effects go, if you check back to the 1st power chart shown in my post
of 3rd Feb/page 10 you'll see a notation that mentions it. Anyhow, ram would of course
be dependent on effects of speed/AoA, so 'climb power' would discount it, setting/rating-wise.

Interestingly, Hawker kept the 'chin' radiator for all production Sabre-powered fighters
(likely due to already having developed an effective ground-attack armour suite for the
Typhoon) - & having tested the Mk VI prototype with the same engine as the speedy Mk I
(so finding it ~10mph slower at FTH*) - esp' once the radiator occupied the full chin-scoop,
with oil-cooler/engine intakes relocated to the wing leading edges, per the Bristol-powered
Centaurus radial-engine equipped Tempest Mk II 'tropical clearance' regular-standard fit out.

*With Sabre IV at ~24,000 feet, "459 mph" according to Mason, so no big deal for a future in
'ground attack', certainly not for an already 'jet-bent' RAF top-brass 'scrambled-egg brigade'.


(One small niggle T-C, would you kindly acknowledge 'in clear' any ex post facto addition/
correction editing-alterations to your posts - since its hard to tell without a verbatim quote
made tout suite - to 'capture' your 'original' text otherwise, ta).

[J.A.W.]

...btw
a 'new' Yak-3 was advertised at $425000 - but a P-82 at $12000000
the book says the Yak lands in 545 m but a display pilot refuses to operate with less than 1200 m
also the P-82 aka F-82 could have 'out-Tempested' the Tempest (if it had gone for that role ie first FTH at only 2250')
the 82 was to have 120" Merlins but the ptb refused to pay the $6000 licence fee that RR asked Packard (post VJ day)

btw 2
Wilkinson's 'bible' has misquoted more Sabre powers (than existed in the real engines that that book shows)
3000 hp at SL doesn't exist (this claimed without ADI !) on the actual 3055 hp ADI @ 2250' engine
(Flights plots - throttling loss and iirc because the 17.25 lb boost isn't available at SL)
a reminder - Raymond's 'anti-sleeve' article says sleeve (wall ports) waste engine length (and so waste weight) ....
the reason the Sabre has 2 crankshafts and crankcases ?

T-C, why'd you imagine that Wilkinson's transcription of official figures &/or proof-reading are awry?

Check the 2nd chart of Sabre power/height ratings (also non-ram) back on page 10, & recall the
'Flight' pilot's remarks regarding max-boost (dry) being "available" for take-off during his flight-test
of the Tempest, if he so "preferred it", (& already noted previously in this thread).

As for Raymond's views, he could consider the "waste engine length" of cam drives, (& the many
complexities of reciprocating poppet valve gear), let alone the P-47H, which flew with a Chrysler
liquid-cooled engine V16 of ~36 litres (~same as Griffon & Sabre) but was very much longer than either.

The robust construction of the Sabre VII allowed a max BMEP of 321lb/sq.in, so no "waste weight" there.
A fair number of Raymond's apparently blithe assumptions* do not indicate a well-informed analysis..
..does he take into account the Sabre's markedly (for an aero-engine) over-square bore/stroke ratio?

Even R/R as noted in the 'Flight' article linked earlier in this thread, (annoyingly Flight's archive is
now no longer available online) & showcasing the (oversized/overweight) Sabre-clone, R/R openly
admitted that twin-crankshafts for 24 cylinder inline engines had been found preferable to X-types.

The Merlin-powered P-82 set an excellent non-stop long-range flight for a fighter, when transiting
from Hawaii to the US East Coast (in ultimate 'ferry configuration') yet the 5min limit on high power
settings of the Merlin would not allow any fighter aircraft so powered - to emulate the Sabre's ability
to extend out from 'normal' settings of 2000+hp - for high-speed low-level combat-zone sorties, a
quality that Beamont commented on favourably as Tempest Wingco flying, both for anti-V1 work,
& for post-invasion ops into 'Festung Europa'.

Indeed, Kiwi Tempest pilot Jimmy Sheddan wrote in his memoir that they'd deliberately throttle-back
to a slower cruise in order to try & trick the GAF ground controllers into 'sending some airborne trade
their way', via appearing as being a more tenable 'prospect' to set up for an attempted 'bounce'.

Incidentally, Sheddan was a longtime 486(NZ) Squadron pilot, & recalled earlier, while flying the
Typhoon on combined ops - both as (laden) fighter-bombers with Spitfires as escort, or escorting Mosquitos, the high cruise speed of the Sabre had the Merlin-powered aircraft calling them to
complain that they could not maintain that pace - & could they kindly throttle back...



* Since the Sabre's cylinder ports were top & bottom, no "waste length" is to be seen, due to ports,
& while such a layout necessitates height to accommodate them, width is less, with the notable
absence of any overhead poppet valve gubbins, or anything mechanical moving above the top of
the combustion chamber, & so sparkplugs are ideally located/accessed, as this drawing** shows:



** Edited to add illustrative diagram to post.

[Tommy Cookers]

* Since the Sabre's cylinder ports were top & bottom, no "waste length" is to be seen, due to ports,
& while such a layout necessitates height to accommodate them, width is less, with the notable
absence of any overhead poppet valve gubbins, or anything mechanical moving above the top of
the combustion chamber, & so sparkplugs are ideally located/accessed, as this drawing** shows:
https://i.pinimg.com/originals/24/20/e0 ... a24754.jpg
** Edited to add illustrative diagram to post.

BMEP of 321 lb/sqin is of course quite low - it's just a reflection of the manifold pressure

the Tempest's 'ability' ? ....
is a reflection of the high wing loading (45 lb/sq ft) ....

consider if a Westland Whirlwind-type of design had the benefit of the years that the Sabre/Typhoon sucked up
it had 24 cylinders and was lighter than the Typhoon/Tempest and had a smaller wing (and better flaps and slots)
https://www.whirlwindfighterproject.co.uk/
the 5 parts under Technical .. Info ... are very interesting

the Tempest has a 5 min limit on high power - per flight (much less if you used ADI for takeoff)
Merlins without ADI have a 5 min limit on high power - per 5 min

the Sabre is wall ported .... it's clearly shown on some drawings that ....
manifolding encircles the cylinders and so forces the cylinder centre distance to be greater (than in the conventional)
so crankshafts are longer - forcing them to bigger everywhere to keep the required torsional frequency
so more bearing friction and disproportionately more weight (as the crankcases etc)
this of course doesn't happen in radials with sleeve-valves


the '2000 hp engine' concept was a dinosaur - having the traditional large level of heat loss to coolant
'they' didn't notice it was a (weakly) compounded engine .....
(supercharger and piston compression - then piston and exhaust-jet expansion)

the compounded Allison V-1710 had 3000 hp and 20% better bsfc in cruise ... and ...
more compounding ie balanced compounding ie 3 compression sources and 3 expansion sources
and a lower CR ie 6:1 got them almost 1000 hp exhaust turbine recovery
it was a high-altitude engine ....
a 'Tempest-altitude' 1710 engine would have been much easier and better

[J.A.W.]

BMEP of 321 lb/sqin is of course quite low - it's just a reflection of the manifold pressure

the Tempest's 'ability' ? ....
is a reflection of the high wing loading (45 lb/sq ft) ....

consider if a Westland Whirlwind-type of design had the benefit of the years that the Sabre/Typhoon sucked up
it had 24 cylinders and was lighter than the Typhoon/Tempest and had a smaller wing (and better flaps and slots)
https://www.whirlwindfighterproject.co.uk/
the 5 parts under Technical .. Info ... are very interesting

the Tempest has a 5 min limit on high power - per flight (much less if you used ADI for takeoff)
Merlins without ADI have a 5 min limit on high power - per 5 min

the Sabre is wall ported .... it's clearly shown on some drawings that ....
manifolding encircles the cylinders and so forces the cylinder centre distance to be greater (than in the conventional)
so crankshafts are longer - forcing them to bigger everywhere to keep the required torsional frequency
so more bearing friction and disproportionately more weight (as the crankcases etc)
this of course doesn't happen in radials with sleeve-valves


the '2000 hp engine' concept was a dinosaur - having the traditional large level of heat loss to coolant
'they' didn't notice it was a (weakly) compounded engine .....
(supercharger and piston compression - then piston and exhaust-jet expansion)

the compounded Allison V-1710 had 3000 hp and 20% better bsfc in cruise ... and ...
more compounding ie balanced compounding ie 3 compression sources and 3 expansion sources
and a lower CR ie 6:1 got them almost 1000 hp exhaust turbine recovery
it was a high-altitude engine ....
a 'Tempest-altitude' 1710 engine would have been much easier and better

T-C a check on your assertions shows that a max BMEP of 321psi = 22.1 bar, which reflects
both fairly good volumetric efficacy characteristics & a robust construction,(its porting def'
does not envelope the cylinder like a modern crankcase-blown 2-stroke) & at 1000hp over
the 2000hp "dinosaur" value, itself a figure which could be exceeded as a 'normal' setting,
in the Sabre, unlike the "5 min limit" of the 2000hp Merlins.

The turbo-compound Allison V-1710 was a 'paper tiger', a fantastical device that was never
able to match in metal the claims made for it, (a bit like the R/R Vulture, & German 24's).

Of course, the 'orphan' Whirlwind (like the Spitfire) lacked the Typhoon's Sabre-given ability
to overhaul FW 190 'Tip & Run' raiders fleeing back across the Channel to France, sprinting at
low-level after putting in brutal 'under the radar' bombing/strafing runs on Southern England.

As for the Tempest having a "45lb/sq ft" wing-loading, the AFDU report linked below states
'37.4lbs' (along with noting the Tempest wing high-Mach capabilities in ASI/height figures).

In fact, although the Tempest under evaluation is an early production example, with its Sabre
running at very modest boost, (but still the only successful wartime British 2000hp plus engine)
& lacking the spring tab ailerons of later production runs, it still impresses as the most effective
air-superiority fighter at tactical heights suitable for the pending invasion, available to the Allies.

http://www.wwiiaircraftperformance.org/ ... tafdu.html

[Tommy Cookers]

by Tempest standards the Dornier 335 was a better plane than the Tempest
Closterman didn't go after 335s
a person disapproving of 1000cc 4 stroke Moto GP wrt 500cc 2 stroke Moto GP shouldn't like either
Bearcat, anybody ?

2 Sea Furies here have crashed recently (no fatalities), the last missing someone by 'a metre'
and on TV Guy Martin was re-flying the Battle of Britain (in the 2-seat Hurricane) - they fed him a 109

http://www.thunderboats.ning.com/page/r ... fon-engine is a good read
eg 2 stage Griffons had a light compact supercharger arrangement (compared to Merlins & Allisons)
https://www.bristol-hercules.co.uk/ also
Hercules fiddling being cheaper than Merlin fiddling

there's prohibition of differential braking with Typhoon/Tempest - but .....
Harvard PNs call for differential braking as 'rudder alone may be insufficient to maintain directional control' ...
and proclaim that in some other circumstances 'control may be then found insufficient'
(it's a bouncer I think - maybe the gear is rather forward of the cg)

ram power seems to have been calculated rather than measured - and it's only eg 2% with high-boost engines
a video authority says that eg the 190 showed 1.6 psi ram @ 300 mph sea level
ram raises full throttle height and is absent below full throttle ht
with NA ram would be more useful - it might combine well with a super-compression CR
icing means that there's a recurrent need for 'alternate' ie heated induction air
ram on the test-bed was for getting the carburation right for flight eg the Schneider trophy

said video authority also says 190 drag is less than Mk IX drag (of course it's both less - and more)

[J.A.W.]

by Tempest standards the Dornier 335 was a better plane than the Tempest
a person disapproving of 1000cc 4 stroke Moto GP wrt 500cc 2 stroke Moto GP shouldn't like either
Bearcat ?

2 Sea Furies here have crashed recently (no fatalities), the last missing someone by 'a metre'
and on TV Guy Martin was re-flying the Battle of Britain (in a Hurricane)

http://www.thunderboats.ning.com/page/r ... fon-engine is a good read
eg 2 stage Griffons had a light compact supercharger arrangement (compared to Merlins & Allisons)
https://www.bristol-hercules.co.uk/ also
Hercules fiddling being cheaper than Merlin fiddling

there's prohibition of differential braking with Typhoon/Tempest - but .....
Harvard PNs call for differential braking as 'rudder alone may be insufficient to maintain directional control' ...
and proclaim that in some other circumstances 'control may be then found insufficient'
(it's a bouncer I think - maybe the gear is rather forward of the cg)

ram power seems to have been calculated rather than measured - and it's only eg 2% with high-boost engines
a video authority says that eg the 190 showed 1.6 psi ram @ 300 mph sea level
ram raises full throttle height and is absent below full throttle ht
ram on the test-bed was originally for getting the carburation right for flight eg the Schneider trophy

said video authority says 190 drag is less than Mk IX drag (of course it's both less - and more)

Ta for the links T-C, but I'd reckon you're reaching a fair bit - if you imagine a large twin-engine
in the Dornier 335 could manage hi-G, low-level 'armed recce' sorties better than the Tempest -
esp' given that the USAAF's tactical units withdrew their own P-38 from the flak-hell over Germany,
(expensively attempting to make a medium bomber from them, via 'Droop Snoot') due to excessive
vulnerability/losses & even their other expensively hi-altitude optimised & turbocharged fighter in
the reputedly 'super-rugged' P-47, was also subject to horrendous losses in low-level work...

As for the most recent Sea Fury crash, do note that while the aircraft was wrecked, its sturdy
construction (in a violent 'forced landing' due to engine failure), still kept its occupants alive.

FW 190 aero was variable, the V12 'long nose' types def' showed an advance over the BMW radial,
as well as benefitting from improved ram-air intake, & inherently superior inline exhaust thrust.

[J.A.W.]

Although British test pilot Capt 'Winkle' Brown found the Dornier Do 335 to be of evaluation interest,
& while he certainly remarked positively on its flight performance - he did not regard it as a machine
suited to proactively engage in 'dogfighting' A2A combat - versus late-war single-engine fighters.

Linked below, this Finlander's website has a worthy compendium of Do 335 material:

https://brakedrum.kuvat.fi/kuvat/Werkos ... 2Pfeil%22/

[Tommy Cookers]

the 109 K-4 (made from Aug 1944) is another candidate ....

2000 German hp on MW & '100 Octane' C-3 fuel (via 1.98 MAP and rpm raised to 2800)
453 mph @ 20000' and 4000 fpm climb - maker's figures at representative 7500 lb wt
thinner prop blades
single-stage supercharging

109s already had ....
reduced ground angle via lengthened ie retractable type tailwheel strut
centrifugal oil scavenge separator for bearing reliability


btw
NACA showed 30% prop efficiency at 25 mph (takeoff of a 1600 hp fighter)
more evidence that full power wouldn't be used at low speeds (it would have been worse than pointless)
(also P-47 WI was useable manually from low boost ie partial throttle early in takeoff)

MW/WI seems to have given more speed than suggested by increased crankshaft power alone .... because ....
exhaust thrust efficiency (and 'thin' prop efficiency ?) increase with speed (helping planes with high wing loadings)

NASA shows ....
neither the intended benefits of laminar airfoils nor their 'planned inferiority' in high Cl 'turning matches' happened
https://history.nasa.gov/SP-468/ch5-2.htm

[J.A.W.]

the 109 K-4 (made from Aug 1944) is another candidate ....

2000 German hp on MW & '100 Octane' C-3 fuel (via 1.98 MAP and rpm raised to 2800)
453 mph @ 20000' and 4000 fpm climb - maker's figures at representative 7500 lb wt
thinner prop blades
single-stage supercharging

109s already had ....
reduced ground angle via lengthened ie retractable type tailwheel strut
centrifugal oil scavenge separator for bearing reliability


btw
NACA showed 30% prop efficiency at 25 mph (takeoff of a 1600 hp fighter)
more evidence that full power wouldn't be used at low speeds (it would have been worse than pointless)
(also P-47 WI was useable manually from low boost ie partial throttle early in takeoff)

MW/WI seems to have given more speed than suggested by increased crankshaft power alone .... because ....
exhaust thrust efficiency (and 'thin' prop efficiency ?) increase with speed (helping planes with high wing loadings)

NASA shows ....
neither the intended benefits of laminar airfoils nor their 'planned inferiority' in high Cl 'turning matches' happened
https://history.nasa.gov/SP-468/ch5-2.htm

Like its British equivalent in the Spitfire, the Me 109 was an excellent 1930s
design, good enough to stay in service/in development right through the war,
as a competitive combat aircraft - a rare achievement for fighters - indeed.

However, both these machines were by 1945, somewhat overdeveloped 'hot rods',
(kept in production by wartime exigencies) with engines that overpowered their
airframes & tended to make them a fair handful for their own pilots, as well as
the enemy.

Mercedes-Benz had significant difficulties with their DB 601-5 development, not
least with complexities stemming via the crankshaft/lubrication set-up redesign
inherent in moving from rolling element to plain bearing function.

AFAIR, another feature of ADI use for take-off in the huge P-47 Thunderblot
was to reduce the propensity of turbo-compressor surge/stall (which in an
aircraft fully loaded with many hundreds of gallons of avgas & taking nearly
a mile of runway to 'unstick'), something def' to be avoided, lest a nasty
rolling crematorium incident be set in train...

As for the actual/useful characteristics of low drag 'laminar flow' wing profiles,
you need only refer back up the page to the 'Tactical Comparison' linked in an
earlier post, & check the difference between the (otherwise similar) Typhoon
& Tempest.. (or, given that the Tempest had gained in wing area - a comparison
between Spitfire & Spiteful - where the 'laminar flow' wing was smaller in area).

[tok-tokkie]

Bristol Centaurus

This thread has been mainly about the Napier Sabre but it also discusses the Bristol Centaurus. It was used in the Hawker Sea Fury which came with the Centaurus engine usually but there was one with the Sabre.

I was looking into the Blackburn Beverly a while back. An interesting aircraft which I saw overhead in Cape Town when I was a school boy. A nice fundamental design = a great big cargo box with wings & 4 engines. Slow and stately; cruise at 275 kph, max at 380 kph with a range of 2000 km carrying 13 tonnes. Entered service 1957. 49 were built.

Compare that to the Lockheed Hercules. Cruise at 540 kph, max 590 kph, range 3 800 km. Vastly superior to the Beverly thanks largely to the turboprop engines. Entered service 1956. Over 2 500 built.

I can’t find the thread which describes the oil tank added inside the wing with a pump and valves so the engines could be topped up in flight with ease.

Good engine & suitable for a fighter but of limited use in a long range or long duration aircraft.

https://en.wikipedia.org/wiki/Blackburn ... _SilhU.jpg
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Some quotes from this Beverly reminiscence thread https://www.airliners.net/forum/viewtopic.php?t=728217
Taken all in all, the Beverley is an ideal aircraft for a civilian enthusiast with a million pounds, a private oil well, and a total abhorrence of flying."
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Amongst its other peculiarities was the rather high oil consumption. The four big Centauri were classed by us as oil burning, petrol cooled and to cope we carried an 84 gallon overload oil tank in the 'dog kennel' at the rear of the flight deck. At approximately 2 hour intervals, we had to go back and, selecting each engine in turn, hand pump the requisite top-up amount. A couple of hours cruise at 8 - 10000 meant the oil was VERY hard to pump and, aircraft unpressurised and being a heavy smoker did not help !
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One article I read about the Bev. said it only needed a navigator on the way out, because on the way back the pilot just followed the oil slick!
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Another thread https://www.key.aero/article/blackburn- ... r-out-east
Terry Bell added: “I recall the Beverley had a reputation for being an ‘oil pig’ with leakage and consumption being noteworthy at times. The standard joke was if asked what the ‘miles per gallon’ were, the response was ‘are you referring to oil or fuel’?”
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