How The Spitfire Mk XIV Compared to the K4 and Other Questions

[GregP]

I think it would be different, Wayne, but they never made one and we'll never know for sure. Not worth an argument, though.

For whatever reason, they seemed to like inverted vees and we seemed to like upright vees. It's curious to me that more than one German manufacturer used the configuration and NONE of our engine designers did. I can say I like the sound of a DB 60 X, but that is more a funtion of the exhaust stacks than the configuration, since both are V-12s, and the fact that, at startup a carbureted engine surges and fuel injected engine doesn't.

I had a Kawasaki GPZ-1000 and it started up exactly the same on a frigid day as on a very warm day ... no diffrence in sound and no hesitation or surging. All the injected modern aircraft I have flow are the same except some of the Lycomings don't really like to start when they're warm unless you use EXACTLY the right technique. The warm engine tends to vaporize the fuel in the injector lines near the exhaust stacks and you have to get the vapor out to start it.

I wonder if they had that trouble with DB 60 X engines. I've never seen it mentioned in any reports of Bf 109 flying or Bf 109 mechanics' writeups that I have read and so suspect not.

 

[GregP]

Duplicate post for some reason ...

 

[wuzak]

I think it would be different, Wayne, but they never made one and we'll never know for sure.

Just think of spinning the engine around the axis of the prop. Then change the oil and sump arrangements to suit.

 

[wuzak]

I think it would be different, Wayne, but they never made one and we'll never know for sure.

Just think of spinning the engine around the axis of the prop. Then change the oil and sump arrangements to suit.

 

[BiffF15]

Gents,
Thanks for the answers to the "inverted V" questions! Some I had heard / read before and others I had not!
Cheers,
Biff

 

[Denniss]

The Me 209 II had an annular radiator
The extra weight forward could be compensated by ballast or by lengthening the rear fuselage.

And we all know how miserably it failed - was slower and less maneuverable than standard 109. Fw 190 was a different beast as airframe was already used with heavy engine forward. But even the 190D was known to be not that agile as the 190A in certain aspects.

 

[tyrodtom]

I think another advantage of the inverted V configuration would be that it might have been a little easier for the ground crew to work on.
A lot of the maintenance of stressed reciprocating engines involves the spark plugs and valve train, more of that work could be performed on low platforms, or maybe even from ground level.

I know from my own experience there's a great deal of difference in degree of difficulty of working on a ordinary car engine and a semi truck, because with the truck it adds a lot of time just climbing up a platform, or onto the engine itself, where with a car I could just bend over and do it.

I remember years ago when I was working on Hueys and OH-6s, a lot of the work was at night, and elevated. When you needed another tool, you either had to get down and get it, or have someone throw it to you. We were sometimes working outside, and usually without good light, so getting thrown a tool sometimes didn't work so well.

 

[fastmongrel]

The engine didnt have to be inverted for a Motor Cannon or Engine mounted cannon so it must have been for visibility or something as simple as fashion. Inverted engines were the very latest inthing around the time DB, Junkers and RR were putting the first proposals on paper for the wartime engines.

 

[Jaivan]

And we all know how miserably it failed - was slower and less maneuverable than standard 109. Fw 190 was a different beast as airframe was already used with heavy engine forward. But even the 190D was known to be not that agile as the 190A in certain aspects.

Do we, really?

Is there any primary source on the flying qualities of the Me 209 "II", or even for its flight/cooling performance?

 

[stona]

Inverted engines were the very latest inthing around the time DB, Junkers and RR were putting the first proposals on paper for the wartime engines.

But they only did so to fulfill a requirement. Daimler Benz made it clear at the time and subsequently that they would have preferred an upright configuration.

Coincidentally Rolls Royce were flirting with an inverted V configuration at this time and some members of the German committee were in the deputation that saw a Rolls Royce mock up, an ancestor of the PV 12/Merlin, in 1933. The RR report quoted above wonders whether this had influenced the German choice, but given the date I doubt that it did.

Cheers

Steve

 

[dedalos]

And we all know how miserably it failed - was slower and less maneuverable than standard 109. Fw 190 was a different beast as airframe was already used with heavy engine forward. But even the 190D was known to be not that agile as the 190A in certain aspects.

The bf 209 II prerformed purely because it weighted much more than the Bf 109. It use the jumo213, 200kgr + heavier than the the db605,new landing gear, bigger wing etc.
A Bf 109 with annular radiator for the DB 605 would not be heavier thatn the standart vertion. And propably would have a slight drag advantage , plus better cooling

Accordin to Erich Brynotte , a veteran of JG51, the D9 could out run, outaccelerate, out turn,the Fw 190A6. Also it had more elegant handling, similar roll rate and superior manouverability. At high speed could outturn the bf 109 as well. Actually he states that the 190a in comparison to 190D was like a comparison between an agricalture horse and an arabian race horse. You can find his interview at the u tube

 

[Koopernic]

The origin of the inverted V-12 German Aero engines goes back to 1928 when a committee of aeronautical experts was assembled in Berlin at the bidding of the R.V.M. Representatives from the Army, the D.V.L. research centre, the Navy (airships were at their peak in 1928 ) and Deutsche Lufthansa were instructed to make an in-depth study of of the international scene regarding aero-engines and then produce specific guide lines for the future development of large air and liquid cooled motors.
Along with others, Prof. Wunibald Kamm, Ing. Wolfram Eisenlohr and Dr. Helmut Sachse (later heavily involved in the design of the B.M.W. 801) served on this panel. The specifications drawn up by this "think tank" were very detailed and incorporated some very advanced features including, for the liquid cooled engines:
1) 12-cylinder, inverted installation,
2) mono-block cylinder banks,
3) wet cylinder liners,
4) propeller reduction gear,
5) supercharger,
6) fuel injection,
7) high temperature glycol cooling,
8 ) provision of a cannon tunnel in the V.

Tender documents were sent to Daimler-Benz, Junkers and B.M.W. all of which eventually produced a V-12 engine model in response although none was able to incorporate all of the required features immediately.

Wolfram Eisenlohr was interviewed in 1980 regarding the 1928 requirement for inverted V-12s and he cited three reasons for the decision.
1) more compact installation.
2) better pilot view for single engine aircraft,
3) less exhaust flame dazzle during night flying.

This is confirmed in a Rolls Royce report titled "Comments on Visit to Germany, July 24th 1945 to August 12th 1945". In the report the RR engineers comment that:

"A good example of Air Ministry control lies in the inverted Daimler-Benz engine. The D.B. people said that both from a technical and production point of view they would have preferred to make an upright engine but they were compelled to make it inverted by the Air Ministry."

There were problems with the inverted V. The same report says that the DB engineers acknowledged this.

"It was very difficult to obtain consistent oil consumption and due to the rotation of the crankshaft, one bank gets more oil than the other. For this reason the engine is built with a lower compression ratio on one bank than the other."

Which may have answered another oft posed question.

Cheers

Steve

The DB605 had a master connecting rod from piston to crankshaft on one cylinder bank and a slave connecting rod attached to the master rod. It was like a radial engine in this regard. That's would indirectly lead to the different Compression Ratios as the slave rod is no longer connected at the crankshafts axis. Ive not run this through a excel simulation but its a given to me that radials had sligly higher CR on the master rod. Other explanations are that the airflow paths for left and right bank were different (which doesn't make sense as the manifold seems to be symmetrical) and that the CR was deliberately like this. It's possible to use a Y fork arrangement to attach to the crank shaft instead of a slave conrod.

 

[wuzak]

The DB605 had a master connecting rod from piston to crankshaft on one cylinder bank and a slave connecting rod attached to the master rod. It was like a radial engine in this regard. That's would indirectly lead to the different Compression Ratios as the slave rod is no longer connected at the crankshafts axis. Ive not run this through a excel simulation but its a given to me that radials had sligly higher CR on the master rod. Other explanations are that the airflow paths for left and right bank were different (which doesn't make sense as the manifold seems to be symmetrical) and that the CR was deliberately like this. It's possible to use a Y fork arrangement to attach to the crank shaft instead of a slave conrod.

That would be incorrect. The DBs had fork and blade rods.

http://www.ww2aircraft.net/forum/engines/inverted-engine-vs-engine-29473-10.html#post800873

 

[GregP]

Beat me to it, Wayne!

DB 605 components:

 

[Koopernic]

That would be incorrect. The DBs had fork and blade rods.

http://www.ww2aircraft.net/forum/engines/inverted-engine-vs-engine-29473-10.html#post800873

Not according to this:
Daimler-Benz DB 601

The paragraph is headed DB605 construction.

"The pistons were forged light-alloy with concave heads and each piston had a floating wrist pin. There were three compression rings and two oil-scraper rings, with one below the piston pin. The master connecting rods utilized roller bearings, with three rings of 24 rollers each. The slave rod was keyed to the outside of roller race and had a lead-bronze bearing over the race."

Of course the article may be wrong and there were also different variants.

 

[GregP]

It's fork and blade ... look at the fork rod in the 1st open cylinder with the center bearing ready for the the blade rod.

 

[wuzak]

Not according to this:
Daimler-Benz DB 601

The paragraph is headed DB605 construction.

"The pistons were forged light-alloy with concave heads and each piston had a floating wrist pin. There were three compression rings and two oil-scraper rings, with one below the piston pin. The master connecting rods utilized roller bearings, with three rings of 24 rollers each. The slave rod was keyed to the outside of roller race and had a lead-bronze bearing over the race."

Of course the article may be wrong and there were also different variants.

It says master and slave, but describes a fork and blade system.

This is what a master and slave rod configuration looks for a Vee engine

 

[GregP]

Koopernic,

The 605 was a bored out 601 and the 601 used fork and blade rod, like the Merlin and Allison.

 

[Milosh]

It says master and slave, but describes a fork and blade system.

This is what a master and slave rod configuration looks for a Vee engine

Add a few more slave rods and one has a radial engine. According to an article Greg posted in another thread, each cylinder of a radial engine had different CRs.

http://www.ww2aircraft.net/forum/engines/cylinder-dimensions-armstrong-siddeley-deerhound-44001.html Post #8

 

[GregP]

I'm not exactly sure if they had different CRs, but they did have slightly different strokes. It would be possible to shape the heads such that that the CR's were equal with the very slightly different strokes. But I suspect Milosh is right since they PROBABLY made each combustion chamber the same size ... being without CNC machning capabilities at the time.