Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: Karnak on October 31, 2005, 04:18:47 AM
-
Engine power is, to a large degree, the determining factor in how powerful a fighter can be. I am wondering what the most powerful domestic engine each or the six warring nations got into significant service was? What I mean is engines that were used in the hundreds or thousands, not a few tens of custom built engines.
Germany: BMW 801Dg at 2,100hp?
Italy: Piaggio P.XIX at 1,175hp?
Japan: Ha-45-21 at 1,990hp?
UK: Napier-Sabre at 2,180hp?
USA: R2800-77 at 2,800hp?
USSR: ASh-82FN at 1,850hp?
What are the correct answers. Those are my guesses, but I am not sure.
-
UK: Griffon 61 at +18 boost makes how many hp's?
-
2,050hp on the Griffon 65 at +18lbs boost Angus. If +21lbs boost I think it is in the 2,300s.
-
Wholly cow!
Was that in service in WW2? Spit 21 maybe?
-
Spitfire Mk XIV uses the Griffon 65.
-
Napier Sabre IIC - 2400hp (Typhoon) 1945
Napier Sabre IIB - 2420hp (Tempest V) 1944
Napier Saber IIA - 2220hp (Typhoon) 1943
-
Originally posted by Karnak
2,050hp on the Griffon 65 at +18lbs boost Angus. If +21lbs boost I think it is in the 2,300s.
Yeah but some point should be made that the Brits are always giving peak outputs - ie. the Griffon did ~1840 HP at SL, and 2035HP peak at altitutude -, others rarely do, they give max output at usually Sea level, i.e. Americans, Germans and Russians.
Ie. see it's power graph :
http://www.spitfireperformance.com/griffonhp_b.jpg
It only reached 2300 HP in one single point, at all other altitudes it's lower.
Another point is high-alt vs. low alt engines. Griffon vs. Sabre is a good example, the high alt engine is seemingly in disadvantage in output vs the low-alt rated one, because it drives a bigger supercharger, and the peak output (which is always developed at low altitude with mechanical superchargers) is lower. But at high altitude, the Griffon would put out a lot more power..
There's more things to look at. The output on the whole altitude range needs to be considered. Turbocharged or hydraulically clutched engines have pretty linear output over the whole altitude range, there's no bigdrop until the FTH. Most aero engines had fixed supercharger gear ratios, and this resulted the power go up and down, see the Griffon power curve again. IMHO it should be broken down to low alt and high alt engines.
Then there's engine effiency. No matter if an engine develops 10 000 HP, if it weights 3 tons, has a 100 sq.feet frontal area, needs 5 tons of fuel carried for it to get any decent range, and a 20 ton airframe to carry all that... so you have to look at how much useful power is developed, and how much is spent to just cancel out the engine/installation/fuel weight that the particular needs to operate. Powerplant installation is also a big factor.
As for the list, I think the most powerful inline engine (for peak output, note the above about altitude performance) the Germans fielded was the Junkers Jumo 213A-1, with 2240 PS peak output, seeing service with the 190D-9. The DB 605 peaked out at ~2030HP with 1.98ata, 2.3ata was considered/tested and would yield around 2300. I am not sure about the DB 603 service, there were some true beast around on the testpad, but the engine wasn't showing the true potential until '44-45. The BMW 801s may have gone up to 2400 HP in service with the later models, but that's crumpp's table.
-
Good points Kurfurst and I was thinking of some of that last night when I posted, but opted for the simpler post.
The altitude effects on the Griffon and Napier-Sabre are definately significant and other nations definatelty saw that effect too when looking at different engine lines. As to size and frontal area, well, I was asking about engines that saw service in the hundreds and we can safely assume nobody put a destroyer's engine into service in an aircraft. In terms of frontal area I was thinking last night about that in comparing the fact that the bigger Griffon engine has a smaller frontal area than the Merlin it was replacing in the Spitfires.
I discounted the DB605 at 1.98ata for the same reason I discounted the Griffon 65 at +21lbs boost, there seems to be little agreement on not only how much service these settings saw, but if they saw service at all. German fans say yes to the 1.98ata and no to the +21lbs and British fans say yes to the +21lbs and no to the 1.98ata. Personally I think they both saw service, but I don't know to what extent and they might not count as common service engines. In light of the ongoing "debate" (more like two sides screeming past eachother) I opted to count the DB605 as 1.8ata at peak and the Griffon 65 as +18lbs boost at peak, large scale service numbers that are incontrvertable.
I wanted to stay away from engines in development because that opens a huge can of worms. The A7M2 was to be powered by a 2,200hp Mitsubishi Ha-43 of some kind. "In development" engines often failed to produce the desired power or even to be adequately reliable for service, such as the Rolls-Royce Vulture engines which failed on both those points.
-
Add to the list:
Wright R-3350-23 (from 2,200 hp, up to 2,700 hp in later versions).
Pratt & Whitney R-4360-4 (3,000 hp, up to 3,600 hp at war's end).
Packard V-1650-9 (1,930 hp)
My regards,
Widewing
-
It should be pointed out that the Brits did not always give power output at the engines best altitude. The 2420hp Sabre IIB is Sea Level power.
Yeah but some point should be made that the Brits are always giving peak outputs at altitutude
It should also be pointed out that German engines gave their best output at SL and then the power dropped off with altitude.
for the DB605, http://mitglied.lycos.de/luftwaffe1/aircraft/lw/DB605_varianten.pdf
-
Originally posted by Widewing
Pratt & Whitney R-4360-4 (3,000 hp, up to 3,600 hp at war's end).
May I ask what fighters (I assume we're talking fighters here) were using the 3,600hp engine and in what numbers? That is really a lot of power compared to everybody else's engines.
-
>>F2G
Goodyear did undertake part of the production of the F4U, under the designation FG. Hence it developed, late in the war, a version of the Corsair powered by the Pratt & Whitney R-4360 Wasp Major. It was based on the F4U-1D, and intended as a low-altitude interceptor. Such aircraft were required to defend the fleet against Kamikaze attacks.
The early R-4360-4 engine was rated at 3000hp. Because of the greater length of the four-row R-4360 radial, the engine cowling of the F2G was elongated. Together with the air intakes behind the engine cowling, on top of the fuselage, this was an easy recognition feature. The tail surfaces were enlarged, and more fuel capacity wa installed. Goodyear also fitted an all-round vision bubble cockpit on the F2G. This had first been tried on a FG-1A. It was a significant improvement, that for some reason was not adapted by later models of the Corsair.
The first models were land-based F2G-1s, but they were later followed by F2G-2 carrier fighters with hydraulic wing folding.
Production of the F2G ended after eight prototypes, five F2G-1s and five F2G-2s were completed. The original order for 418 F2G-1s was cancelled, because the end of the war removed any need for the F2G. Climb was excellent, 9150m could be reached in 4 minutes. Maximum speed on the other hand was rather disappointing, 32km/h (20mph) down from the expected 724km/h (450mph). The F4U-5, with its uprated R-2800 engine, was faster than the F2G. The F2G also suffered from lateral control problems.
<<<
-
Anything else? If not it wasn't really a service engine, more of a specialty item. When I listed the 2,800hp R2800 I thought of the F2G's engine as well, but didn't go with it due to rarity.
Still, very impressive power on it.
-
Major Wasp was not really something what would you wanna put in a typical WWII fighter. At dry weight of over 3600 lbs and at that time prop limitations, it was just too much of an engine.
-
Originally posted by Karnak
Anything else? If not it wasn't really a service engine, more of a specialty item. When I listed the 2,800hp R2800 I thought of the F2G's engine as well, but didn't go with it due to rarity.
Still, very impressive power on it.
P&W's R-4360 was used on several prototypes that were discontinued to concentrate on jets and was used for heavy bombers and attack aircraft.
Republic XP-72 (499 mph)
Boeing XF8B-1 (432 mph)
Martin AM-1 Mauler (Developed during war, 151 in USN service between 1946 and 1949)
Convair XB-36 (first flown in 1946)
B-29D (later redesignated the B-50)
My regards,
Widewing
-
That is why I specified common service engines. I know there were some pretty nice things just about to come out, but those really fall outside the scope of WWII as the end of hostilities precluded them.
-
Originally posted by MiloMorai
It should also be pointed out that German engines gave their best output at SL and then the power dropped off with altitude.
[/url]
Hmm, you should better check that.
-
Well, what got me thinking was this:
"In terms of frontal area I was thinking last night about that in comparing the fact that the bigger Griffon engine has a smaller frontal area than the Merlin it was replacing in the Spitfires."
Are you really sure? The Griffon has some bulges on the top and anyway, seeing the engines side by side, I rather had the impression that the Griffon was a tad larger.
-
Angus,
The only source I have seen it mentioned has it listed as a smaller frontal area. It is a bigger and heavier engine, but I'd guess it does it through length. I'm sure it is not much smaller in the frontal area in any case.
-
Yup it was length (see it does matter)
Look at difference between a Merlin Spits nose and a Griffon Spits nose, it's really easy to see.
-
I think Spit benefited from Griffons also aerodynamically. The bluntish angle from under the nose was deleted by changing the angle of the engine lower and by a bigger spinner. FrontallyI'd say Griffon is slightly larger but not much (can't say for sure). OTOH it must be slightly smaller if the oil container is under the nose also in Griffon engined Spits. Griffon Spits have those protrusions for camcovers.
The DBs also got larger and, IIRC, in some models of 109 the oilcontainer was made inside the engine mount arm because it did not fit anywhere else (..or was it in 190D?).
-C+
-
Power outputs, the DB 605A delivered 1475 Ps at SL, which is usually qouted, and 1550 PS at 2.1km (peak value). If it would be a British engine, it would be credited as '1550 HP aero engine' after it's peak power output. It's similiar with all DB engines.
The DB 601 and 605 should be nearly identical in size, given the 605 only upbored the 601's cylinders with apprx. 2 liters. Even the Db 603 was not much larger frontally than the 605, though it was lenghtier.
Anyone has Merlin dimensions handy ? I've got them for the Griffon 65 I think.
Charge, I think the Emil had different positioning of the oil tank, but all later Bf 109s (and many other with a DB engine) had their oil tank situated right ahead of the engine, a horseshoe-shaped tank around the reduction gear. I think you mixed up with the two coolant tanks of the DB engine on the sides of the engine.
-
Originally posted by Karnak
Engine power is, to a large degree, the determining factor in how powerful a fighter can be. I am wondering what the most powerful domestic engine each or the six warring nations got into significant service was? What I mean is engines that were used in the hundreds or thousands, not a few tens of custom built engines.
Germany: BMW 801Dg at 2,100hp?
Italy: Piaggio P.XIX at 1,175hp?
Japan: Ha-45-21 at 1,990hp?
UK: Napier-Sabre at 2,180hp?
USA: R2800-77 at 2,800hp?
USSR: ASh-82FN at 1,850hp?
What are the correct answers. Those are my guesses, but I am not sure.
Karnak,
Just a quick search on the web, and I found from Aircraft of the World (http://www.csd.uwo.ca/~pettypi/elevon/baugher_other/) that:
Ki-84 was equipped with the Nakajima Ha-45-21 which rated at 1990 hp for takeoff and 1850 hp at 5740 feet.
and...
N1K2-J was equipped with the Nakajima NK9H Homare 21 which rated at 1990 hp for takeoff, 1825 hp at 5740 feet, 1625 hp at 20,015 feet.
Comparable? I am not sure how many of the Ki-84s were equipped with that specific engine... while the N1K2-J, we know it numbered in the 400s.
-
FDutchman,
Yup, that is the Homare Ha-45-21 engine that I had listed. I know there were more powerful versions of the Mitsubishi Ha-43 engine, but they didn't make it into service thanks to shortsightedness on the part of the IJN/Mitsubishi managers, an earthquake and B-29s of the USAAF.
-
Originally posted by Karnak
FDutchman,
Yup, that is the Homare Ha-45-21 engine that I had listed. I know there were more powerful versions of the Mitsubishi Ha-43 engine, but they didn't make it into service thanks to shortsightedness on the part of the IJN/Mitsubishi managers, an earthquake and B-29s of the USAAF.
oops... ya right ... they both the same engine! :lol
-
Originally posted by MiloMorai
It should also be pointed out that German engines gave their best output at SL and then the power dropped off with altitude.
for the DB605, http://mitglied.lycos.de/luftwaffe1/aircraft/lw/DB605_varianten.pdf
The TA-152 dispells your theory.
Karaya
-
Originally posted by Masherbrum
The TA-152 dispells your theory.
Karaya
It does?
Jumo 213E as used in the Ta 152H
Climb&combat, SL - 1580 hp/3000rpm
Climb&combat, 10.7km - 1260hp/3000rpm
-
The BMW801TS motor was a 2400hp motor at 1.82ata @ 2700U/min.
All the best,
Crumpp
-
It can't be mere coincidence that the most powerful engines were all 2-row radials(excepting the freak sleeve-valve H-24 from the UK)?
-
Originally posted by justin_g
It can't be mere coincidence that the most powerful engines were all 2-row radials(excepting the freak sleeve-valve H-24 from the UK)?
Well, keep in mind that Japan did no serious development of liquid cooled engines, so that discounts Japan. In Germany the big Daimler-Benz 605 peaked at over 2,000hp. The liquid cooled Griffon 65 peaks at about 2,200hp.
So looking at that the only engine that stands out significantly is the massive R-2800 series of two row radials from the USA. All the peak engines from the UK and Germany are in a pretty tight cluster for peak power, a lower grouping for Japan and the USSR and Italy isn't even in the competition.
-
What good is power if it's useless?
Pony had a british engine and it wasnt most powerfull.
Even these days big american engines have megatons of power but not faster than twice smaller geman engines.
I'm talking cars.
-
Because power isn't useless.
-
One thing is wonder about how important is torque for an aero engine. Does higher torque for aircraft yield an advantage, or it's a secondary issue? Anyone with an answer to that?
-
Hi Justin,
>It can't be mere coincidence that the most powerful engines were all 2-row radials(excepting the freak sleeve-valve H-24 from the UK)?
The V-12 engine and the double-row radial were the engine patterns that were state-of-the-art in the late 1930s, and developed to perfection in the early 1940s. Of these two types, the double-row radial naturally was the more powerful one since it had more cylinders of the same (technologically determined) dimensions. V-12 engines had the advantage of greater aerodynamic efficiency, yielding about the same kind of fighter performance from lower absolute power, and were used almost interchangably with the double-row radials.
More complex engine arrangements than these were introduced in the early 1940s, but failed to reach production status (or in the case of the Sabre, reached it after going through considerable problems). They used more complex arrangements to achieve a higher cylinder count, outperforming both the V-12 and the double-row radial, but engine development was slow and so they made hardly any impact on the course of the war.
We'd certainly have seen more three-dimensional engine patterns, like the corncob R-4360 or the radial/inline Jumo 222, if the jet engine hadn't appeared on the scene.
Regards,
Henning (HoHun)
-
Originally posted by Kurfürst
Does higher torque for aircraft yield an advantage, or it's a secondary issue?
Generally torque is not issue at all in the aero engines due constant speed propellers (or propellers with similar functionality). Only output matters.
gripen
-
Touque * RPM
is the formula for horsepower, so I guess it a bad thing to be without.
-
Originally posted by Debonair
Touque * RPM
is the formula for horsepower, so I guess it a bad thing to be without.
yes,if you in a bulldozer
-
ahh, actually "Touque * RPM" is the forula for a dizzy Macenzie brother I think
HP = (lb-ft x RPM)/5252 = torque x RPM/5252
-
ah, I think I get what you mean now.
Still I think an aircraft engine needs a big ton of torque to do it's job. Turning those big prop blades especially in coarse pitch has got to take a lot. Compare a little Cessna 150 engine delivering 2500 RPM & 100 HP to a fighter's engine delivering about 20% more RPM, but 2000% more power.
-
Well, it's the output (hp, kW or what ever) which matters regardless what ever rpm torque combination is needed to produce that output.
gripen
-
Originally posted by gripen
Generally torque is not issue at all in the aero engines due constant speed propellers (or propellers with similar functionality). Only output matters.
gripen
Thanks. Now that I think of it, the constant speed prop designs are basically work as constant torque gearboxes. However I'd believe torque has some function in acceleration when throttling up from closed throttle, bigger engines would generally have more torque, and faster acceleration of RPM against airscrew load.
-
DB 610
24 cylinder X engine similar to the British Napier Sabre, based on the DB 605, 2950 bhp at sea level. Powered the He-177 Greif bomber.
DB 613
Similar to the 610 except it was based on the bigger DB 603, 3800 bhp at sea level. Developed to power the Do-214 and He-519, but cancelled with the rest of the German bomber program.
-
Interesting thing, - the torque.
From Gripen:
"Well, it's the output (hp, kW or what ever) which matters regardless what ever rpm torque combination is needed to produce that output."
Torque is measured in Nm/time. A horsepower is also a force in time, - if my memory is right, the force to lift 75 kg's up one meter in one second.
Torque has been explained to me as toughness, - i.e. Hp relative to RPM and the swiftness to get to the hp between various RPM's.
You would think it would be rather similar numbers, - but no. I remember 2 engines that were "in my service" at the same time.
One was a petrol engine, 1.6 l., Torque 90 nm, Hp 86, rpm probably 5000 at the time.
The other was a diesel, 3.86l., Torque 356 nm, Hp 90 at 2300 rpm. I belive the max torque was achieved at a lower rpm, but not sure. BTW, that was a turbo engine.
Any comments on that? There's got to be someone on the board that knows this from one end to another.
BTW, as a sidenote, the Diesel powered big things, while the petrol engine powered smaller, - the Diesel used quite a bit less fuel, - peaking out at 10L on the hour with full power.
-
Originally posted by Kurfürst
Anyone has Merlin dimensions handy ? I've got them for the Griffon 65 I think.
-------------------DB 605----------MerlinXX
Width:------------720mm----------757mm
Height:-----------1010mm---------1046mm
Length:----------1740mm---------1793mm
Frontal area:------0.51sq.m--------0.54sq.m
Source: MERSSERSCHMITT JA SAKSAN SOTATALOUS, Hannu Valtonen
-
Torque is force * length, power is force* length / time.
So it is diffrent.
There is a fixed number to get from troque and revolutions per second to power.
High rpms and low torque put out similar power than low rpms and high torque.
So torque is diffrent from power, but you can convert it. And you need enough torque to get an rpm change, so driving a heavy truck with a low torque engine is difficult because you would have to put it to high rpms before letting the clutch go in... thus having a lot of loss and need a lot of gears because of the small usable rpm band. At some point it gets impossible cause the small rpm band you can use doesnt make your truck move that much faster that you can go into next gear.
High torque from low to high rpms = less shifting necessary, good for heavy vehicles vehicles ( you need the band).
High horsepower and good fuel efficiency at one specific rpm, crap torque and therefor crap hp at all other rpms, peak of torque and hp at the same point = good for plane and ship, cause you can run em at one rpm setting all the time.
-
Hi Karnak
>USA: R2800-77 at 2,800hp?
I believe when including a turbocharged engine in the comparison, it would be necessary to establish the contribution of exhaust thrust that the mechanically-supercharged engines enjoy to a much larger degree.
(I thought WW2 turbochargers would not provide any exhaust thrust at all, but apparently, there were two different types of turbines, and only the equal-pressure turbines could not yield any meaningful thrust. I learned this from a recent article on the turbocharged BMW801 in the German Flugzeug Classic, but haven't been able to figure out which WW2 aricraft had which type of supercharger. The Allisons of the P-38 apparently used equal-pressure turbines as there is one quote from Clarence Kelly expressing regret that he couldn't exploit exhaust thrust in his design.)
Anyway, the R2800-77 quoted above would have to be compared to the Jumo 213A (which is one of the few engines I have seen exhaust thrust data for) based not on the latter's 2140 HP shaft power, but to about 2300 - 2600 HP shaft equivalent power depending on speed. (As a rule of thumb, in a climb the turbo-charged engine compares more favourably than in level level flight.)
I suspect the R-2800 would also add a bit of exhaust thrust on its own, based on the location of the exhausts on the P-47, but that's just a suspicion so far. Any data would be welcome! :-)
Regards,
Henning (HoHun)
-
Schutt:
Aero engines then have reasonably good torque, for the peak output is at a rather low RPM, if you compare for instance, with Formula cars, yes?
-
It was developed during the war but never saw service. Pretty mean looking bugger too. 3500hp
http://www.wpafb.af.mil/museum/engines/eng34a.htm
-
XR-7755, but "service engines" is the requirement here