BMW 139 information

[Shortround6]

Probably in an aircraft other then a mass production installation. That's how Germany did things. For instance the Jumo004A jet engine first flight test on March 15, 1942 while installed in an Me-110.

It's how most people did things.

P&W used a Vultee A-19 test fly the R-2800.
THE A-19 was used to test fly a few other experimental engines too.
Fairey Battles were popular engine test planes in England.

The book "The Engines of Pratt Whitney: a Technical History" by Jack Connors list a first flight for the R-1830 in 1931 but again lists the Martin 130 as the first Commercial plane to use it. One or two Junkers JU 90s used it and the DC-3A.
Early Military versions are the -1- used in the XB-14, the -7- used in the XA-16, the -9 used in the XA-16 and the P-35, the -11-used in the XB-15 and the first military engine to be rated at 1000hp.

While I don't have production numbers I don't believe any of these planes with possible exception of the XB-14 were flying in 1934 let alone 1932 or 1933.

 

[stano666]

Nobody bought licences for prototype engines. Anybody who licensed an engine waited a few years to see how they did in service before plunking down any money. Co-production is a different story but that is not what we are talking about here.
Germany was not likely to get a license for the R-1830 in 1936 or 37 because Hitler was already making himself rather unpopular by that time.[/QUOTE]

Plus Hitler liked German "desing" so much, he wouldn't allow foreign engines in luftwaffe planes, sometimes luftwaffe planes used foreign engine (Gnôme in t ju52), but Hitler rather used German stuff just to showoff "german superiority".
I saw a bmw site, saying the 139 engine had 14 cilinders, together what i've read here i asume that's the truth.
Greetings stano666.
P.s. anybody who knows good books on German aircraft engines of wwII?, please share that knowledge, i'd like to buy (a bit more) books on the subject. I've ordered: warplanes of the third reich, german aircraft of the second ww and Hitlers luftwaffe, all 3 are about the planes (in general). So my next step (probably) is German engine (of wwII era) information -tho. every suggestion is welcome-

 

[davebender]

Put Bosch fuel injection and a BMW designed supercharger on the P&W R1830 and call it a German engine. Hitler wouldn't know the difference.

 

[Shortround6]

Why would a BMW designed supercharger be any better than the P&W one?
Especially in 1936-39?

 

[davebender]

Why would a BMW designed supercharger be any better than the P&W one?

Because it will have a fluid coupling similiar to the DB601 engine, providing a nice smooth power curve over a broad altitude band.

 

[Shortround6]

What BMW engine used a fluid coupling to drive it's supercharger and when?

 

[davebender]

I have no idea.

What sort of supercharger arrangement did BMW use for the BMW132, Bramo323, BMW139 and BMW801 engines?

 

[Shortround6]

Either single speed-single stage superchargers or two-speed-single stage superchargers. At least until the mid point of the war when they experimented with more complicated set-ups.
The Armstrong-Siddeley Tiger was the first production engine to use a two speed supercharger and that was in 1936. max boost was 2.5lbs for take off and 0.5lbs of boost in flight.
Nobody's superchargers were very good in the 1936-39 era. Intakes, impellers or diffusers. Not just the drives.

 

[davebender]

Why didn't BMW use a supercharger fluid coupling similiar to Daimler? The Daimler coupling appears to provide a significant advantage for a smooth torque curve.

 

[Shortround6]

patents?
The fluid coupling was more expensive, it was heavier, it needed an oil source and it actually wasn't quite as efficient as gears. While not too bad at full engagement, at low altitude and maximum slip a fluid drive could generate a heat load of around 40HP depending on the engine . Larger oil cooler if using engine oil? Germans also had trouble with oil 'foaming'. while the fluid coupling is full at high altitudes, at low altitudes it is only part full and is a wonderful mixing device for oil and air. They had to use an separator because engine oil with air in it doesn't work very well in the bearings.
I believe the DB 600 series used gear drives (actually, they all use at least one set of gears, the fluid drive just replaces the clutch) and it took a while to sort out the problems with the 601.

 

[davebender]

at low altitude and maximum slip a fluid drive could generate a heat load of around 40HP

Perhaps that is the reason.

The DB601 was intended to operate from ground level all the way up to 30,000 feet. A broad torque curve provides a significant advantage in that situation. More then enough to offset the disadvantage of power loss from coupling slippage.

BMW engines were all intended to operate at low and medium altitudes. The mission changed during 1943 when Fw-190s had to intercept B-17 bombers at high altitude. But that mission wasn't even a glint on the horizon during the 1930s.

 

[stano666]

Put Bosch fuel injection and a BMW designed supercharger on the P&W R1830 and call it a German engine. Hitler wouldn't know the difference.

LOL, no he probably wouldn't, but someone would, he'd than probably use that knowledge to blackmail the person's responsible for such a "joke" or -more likely- he'd tell the fuhrer that someone was lying to him, wich Hitler didn't like much -like he'd have to guilty party send to the east much.
But stealing ideas (and even breaking patents what not) was a common thing i guess, with a world war raging (and its multitude of crimes especially Hitler's Germany atrocious ones) that kind of things gets "snowed under"
But i like the topic so i'll let you get back to it, Greetings stano666

 

[Shortround6]

The DB601 was intended to operate from ground level all the way up to 30,000 feet. A broad torque curve provides a significant advantage in that situation. More then enough to offset the disadvantage of power loss from coupling slippage.

I think we have a bit of confusion here. The supercharger drive has nothing to do with the "torque" curve of the engine. If you are referring to the power-output in relation to altitude curves or plots that is something different.

You also have to realize what the different drives can and cannot do. While the DB 601 may have operated "from ground level all the way up to 30,000 feet" the early versions had a full throttle height of between 4-5000 meters depending on the model. power fell at exactly the same rate from that height up to 30,000ft or beyond as if the engine had a plain gear drive for the supercharger.
It is below full throttle height that the fluid coupling provides an advantage. While it takes a few more HP to run than a straight gear it does allow the impeller of the supercharger to turn slower at the lower altitudes and so use less total hp, this leaves more power for the propeller and it heats the intake air less. This is what the low gear in a two speed supercharger does also.
The Fluid coupling smooths out the peaks and valleys or the zig-zag of the 2 speed drive but only below the full throttle height.

Consider the Merlin III and X. The Merlin III had a full throttle height of 16,250ft (4900meters). Power fell off above this height and below. The throttle had to be progressively closed as the airplane lost height to stay within safe operating limits. The supercharger continued to spin a the same speed and so used just about the same amount of power. By the time the plane got to sea level the engine was limited to 880hp instead of the full throttle 1030hp at 16,250ft. The supercharger used an 8.58 drive gear.
The Merlin X used the same supercharger but had the two speed drive with 6.39 and 8.75 gears. Since the power to turn the impeller goes up with the square of the speed we can figure that in low gear the supercharger was taking about 53% of the power it needed in high gear. Full throttle heights were 17,750ft but at a slightly lower power than the Merlin III and 5,250 ft in low gear. The 1130 Hp at that height was a significant advancement over the Merlin III as was the 1075hp for take off. Almost 200 more HP with only a change of supercharger gear.
Fitting a fluid drive instead of the 2 speed drive, if the range of speeds of the fluid drive were limited to between 6.39 and 8.75, would show no increase in power over 17,750 ft and no increase in power below 5,250ft. It would eliminate the dip between 5,250 ft and 17,750ft. and show the most advantage around 10-12,000ft.
It also makes life simpler for the pilot because the early 2 speed drives usually needed to be manually shifted. Later ones were automatically controlled.
The DB drive did exhibit a slightly wider range of ratios than the above. From about 7. something to a max of 10.39? with different intakes, impellers and diffusers direct comparisons of impeller rpm don't mean much. but a slightly wider speed range would be an advantage.

 

[davebender]

he'd tell the fuhrer that someone was lying to him, wich Hitler didn't like much -like he'd have to guilty party send to the east much

Like everywhere else what you could get away with in Germany was largely dependent upon who you were. Huge firms like Krupp and Daimler-Benz pretty much did what they wanted as long as they supported the German war effort.

Daimler-Benz did this to an amazing degree, putting company profits ahead of immediate national requirements. The German Government wanted DB to shift completely to war production but they kept making excuses to keep their automobile producton line operating. DB also made excuses rather then pay for tooling to convert their Genshagen factory from DB605 engine production to DB603 engine production.

 

[stano666]

Mr Goring, and buckets of his associates, were for sale -if you catch my drift- this added a lot of possibility's (sometimes (rarely) good ones) too.
But 'bout the suppercharger fluid cuppeling, a small advantage is still a advantage, with life 'n limbs on stake... -you catch my drift-
Greetings stano666

 

[Shortround6]

But 'bout the suppercharger fluid cuppeling, a small advantage is still a advantage, with life 'n limbs on stake... -you catch my drift-
Greetings stano666

For a fair idea of what the fluid couping was worth go to this website page and look at the power graph.

Kurfrst - DB 601, 603, 605 datasheets - DB 605 A

Now to convert this to a graph showing what a 2 speed drive would do you can ignore the lines both to the left of the first peak and to the right of the second peak. The power output at these altitudes would be the same if the 2 speed drive used the same minimum and maximum speeds as the fluid drive.
Now for the advantage imagine a line (draw on a print out or use a paper edge on the screen) that goes from the LEFT peak to a point in the lower right of the graph that would meet where ALL the lines running to the lower right would meet. Next, add a second line running from the RIGHT hand peak to the lower left using the same angle as one of the 3 lines running from the left hand peaks to sea level.
You will have a "V" connecting the two peaks under the existing curve. The difference in power between the curve and the "V" is the advantage of the fluid drive. It could be as much as 100hp at a certain altitude, it could be 10 hp at altitudes near the peaks. This advantage is purchased at increased cost, complicity, weight and cooling drag. Granted these costs are small but the last two tend to cancel out or shrink the advantage in power when it is small.

 

[stano666]

Tanks Greetings, marry christmas happy newyears, i'm off to the shops, i've gained some good inspiration and nice derections (to dig out ) and going to built some 1:72 scale FW's to play with my niece 'n nephew, maybe we find out some new info on their flying carastistics (higly unlikely tho.)
But the reading was good ones more, many tanks for that see ya