Each nation's most powerful service engine?

[ATA]

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.

[Karnak]

Because power isn't useless.

[Kurfürst]

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?

[HoHun]

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)

[gripen]

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

[Debonair]

Touque * RPM
is the formula for horsepower, so I guess it a bad thing to be without.

[ATA]

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

[Debonair]

ahh, actually "Touque * RPM" is the forula for a dizzy Macenzie brother I think

HP = (lb-ft x RPM)/5252 = torque x RPM/5252

[Debonair]

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.

[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.

gripen

[Kurfürst]

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.

[Steinhoff]

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.

[Angus]

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.

[Wmaker]

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

[Schutt]

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.