BMW Fokker D.VII's

[totalspoon]

Facinating thread.

@ Dave,

I'm not sure I've got this straight. So BMW supplied 220 BMW engines, 27 of which were reinstalled a second time making 247 acceptances in total. Is this right?

Were BMW and Opel the only two suppliers for the BMW engine?

Are there any figures of how many Opel BMW's were accepted?

Thanks

Spoon

[Dave_Watts]

Hi All,

Lloyd, I asked Peter about this "F" designation, and he stated he really didn't know. He was always one to not speculate. I think speculation can lead one to further enlightenment. Imrie was/is always so tight with his information that what he knew he held onto, hopefully if his D.VII book comes to pass we'll see.

Spoon, yes that is correct, 220 BMW motors delivered to Fokker and accepted into 247 aircraft. There may have been a couple more BMW motors delivered that were used in experimental aircraft; V.24, V.34, V.36, and V.38 that were not accepted. Most likely the motors were salvaged for the next project, so possibly Fokker only held one in reserve. The V.24 was fitted with a Mercedes, a Benz, and a BMW.

There were 41 D.VII's accepted with Opel BMW's from September thru November. I can give you listings if wanted. It looks like Fokker recieved 2/3rds of the motors they produced. None were double accepted. I assume they carried the "F" designation. If so it's interesting that none ever came back for reissue/acceptance in a later aircraft. Maybe they were so late to the front. I believe that's the case, I just looked at the acceptances and the latest acceptance for a BMW to be re-installed/accepted is September 6th, the earliest Opel BMW acceptance is September 2nd, and the next is September 12th, so they are outside of the "curve" to have been accepted, delivered, flown, crashed, salvaged, sent to Fokker, installed, and accepted for a second time.

There were 3 Mana motors installed into D.VII's 2 of which were accepted;

Fok.D.VII 4292/18 July 23 Mana III Nr.12
Fok.D.VII 10347/18 Nov. 29 Mana IIIa Nr.23
Fok.D.VII 10348/18 no acceptance Mana IIIa Nr.53

I don't know if the Mana was a "BMW" copy/license built motor, but think not. As well I believe they didn't carry the "F" designation. As I recall there is one of these aircraft on the floor on its side in the Fokker warehouse in a post-war photo, and the motor cowling is off and you can identify it as a Mana aircraft.

Best,
Dave W.

[YavorD]

Originally Posted by Dave_Watts

... to have been accepted, delivered, flown, crashed, salvaged, sent to Fokker, installed, and accepted for a second time.
...Dave W.

Thank you for the information, Dave!
Was it necessary to crash the plane? Can it be engines removed after 50 or 60 hours flight time and sent for major overhaul / reconditioning?
Before this thread I never realized how many and how often engines were reconditioned and re-used on factory "fresh" aeroplanes.
Regards,
Yavor

[Dave_Watts]

Hi all,

Yavor,
I haven't seen direct evidence for BMW, but with Mercedes we know they had these "repair kits" made by Daimler for only what I can say are field repair kits. Its been some time since I looked at one, but they contain a cylinder, piston, rings, connecting rod, bearings, valves, valve springs, and other various parts. When Ken Hyde, (of Virginia, Jenny and Wright Flyer fame/National Geographic/Discovery Channel shows), brought in the Strahle collection with the Halberstadts and Mercedes motors, it also contained these repair kits. When Ken traded the majority to Smithsonian Air & Space, they put a kit out on display with their D.VII with manequins like they were doing a repair on the airplane. I assume BMW made these field kits as well, and motors wouldn't have come back for service to a repair center unless it was major.

Best,
Dave W.

[Dave_Watts]

Hi all,

New direction;

Has anyone done the exercise of figuring out how many "F" D.VII's were made from Fokker, Albatros and OAW? We can only speculate, it will be a ball park number, but better than nothing.

I'll start the ball rolling by using the serial numbers of BMW motors. Lowest/highest serial numbers recorded by Fokker acceptances are 1229/1682, (Fokker also had/accepted motor Nr. V.5), that equals 455 motors as an absolute minimum. There are also the Opel BMW motors, Lowest/highest serial numbers recorded by Fokker acceptances are 12001/12146 that equals 146 motors. If we include the Mana III/IIIa motors lowest/highest accepted, they are 12/53 that equals 42 motors.

BMW #'s V.5 + 1229 - 1682 = 455.
Opel BMW #'s 12001 - 12146 = 146.
Mana #'s 12 - 53 = 42.

Total output = 643 "BMW" motors.

This is an absolute minimum, my guess is BMW could easily be 1200 - 1699, Opel could be 12000 - 12199, Mana 12 - 111. My expansion only raises the pool to 800, but we'll stick to the bare facts of 643.

We established Fokker recieved 220 BMW motors installed/accepted into 247/245 aircraft. 41 Opel BMW motors into 41 aircraft. 3 Mana motors installed into 3 aircraft, 2 accepted.

Total Fokker output of "F" aircraft = 291 made/ 288 accepted.

Using only the serial number ranges we are left with the following motor numbers for Albatros/OAW and everyone else like Pfalz D.XII.

BMW 255 motors
Opel 105 motors
Mana 39 motors

That gives us 399 motors for everyone else.

Once we get a pool number for Albatros/OAW we can use the same re-install rate of 12% of the strictly made BMW, no others/same as Fokker .

We could get into another discussion of how many of these would have seen action, but let's first nail down numbers made/accepted and more importantly who else got how many BMW motors from the limited pool of 400.

Okay Dan-San, and others, help me out with who else used BMW's and an idea of how many, rough estimates?

Also Dan-San, or others, what is the performance numbers for the Mana IIIa, as I'm including it at this time?

Have we done this exercise before?

Best wishes,
Dave W.

P.S. Dan-San you never answered my questions I put to you of "Dan-San, do you think the range you cited as "231/18 - 245/18" is too restrictive as those first delivered to Jasta 10/JG1? I assume your range came from observed aircraft in the Friedrich's wreck photos?" I just wanted a source for your range.

[YavorD]

Thank you, Dave!
My impression (from a very limited sources) is engine swap being quite common practice. There is a Bz.III example from an FF.33L. It should be much easier in Germany than in remote naval air station on the Black Sea coast.
Regards,
Yavor


(Extract from a report held at Public Record Office in Kew)

[Dan_San_Abbott]

Hi Dave:
I agree, Fok.D.VII 231/18F should not be listed in the possible D.VII aircraft issued to Jasta 10. Fok.D.VII 230/18 went to OAW. There is a rear view photo of this machine at Adlershof clearly marked as OAW. I don't know which D.VII was sent to Albatros as their standard.
I think if MvR had been issued a Fok.D.VII before his death on 21 April 1918, there would have been a plethora of photographs taken with Tony Fokker, General Hoeppner there as well as other notables, such as took place with the two Fok.F.I machines on 28 august 1917. There may have been a Fok.D.VII (most likely D.VII 231/18F as you suggested) scheduled for him but his death that stopped the process. I think it would have been a big deal.
The fact that there are no photographs, leads me to believe it never happened.
The Machinen Fabrik Augsburg Nürnenburg, M.A.N. manufactured the 199Argus AsIII MAN 180 Ps under license. M.A.N. designed and built 73 M.A.N.IIIa 185 Ps at 1400 rpm, six cylinder engines with a bore of 140m and stroke of 170 mm. A further developement of the engine was the M.A.N. IIIav of 220 Ps at 1400 rpm with the bore increased to 150mm and the stroke of 170 mm there were 4 of these engines built at the end of the war. The M.A.N.IIIa was used in the Fok.D.VII. These engines were built at the Augsburg Werke.
Blue skies Dave,
Dan-San

[Dave_Watts]

Hi all,

Dan-San,
Thank you for addressing my question to you. I still am wondering where/how you know/speculate "232/18 - 245/18" as those first delivered to Jasta 10/JG1? I just wanted a source for your range as I'm interested in these aircraft.

Hannes or other experts,
I swear I've seen a list posted on the Aerodrome on one of the threads that lists total production numbers for different German flugmotors. I tried searching the Aerodrome's old threads, but no luck. Anyone have it?

Best wishes,
Dave W.

[YavorD]

Originally Posted by Dave_Watts

...
I swear I've seen a list posted on the Aerodrome on one of the threads that lists total production numbers for different German flugmotors. I tried searching the Aerodrome's old threads, but no luck. Anyone have it?
....

Hi, Dave!

I have manufacturer and engine type-specific data only for Maschinenfabrik Oberursel AG. The source is Die Umlaufmotoren der Motorenfabrik Oberursel A.G. by Achim Sven Engels, 2000, E-Book, neue erweiterte Auflage, 191 S., Deutsche Flugzeugtechnick 1900-1920 (CD 3), ISBN 3-930571-60-9.

Baujahr ........ Motortyp ....... Stückzahl
-----------------------------------------
1913/13 (sic!) ..... U 0 ............. 383
1915/16 ............. U I ............ 1009
1914/16 ............. U III ........... 595
1917/18 ............. UR II ........... 575
1917/18 ............. UR III .......... 211
1918 ................. UR IIa ............. 1
1918 ................. UR IIIa ............ 1
1918 ................. U IV ............... 1
-----------------------------------------
Total ................................... 2776

There is an article, published by Wilhelm Hoff (Z.A.K.) in Z.VDI, 1920, and translated by NACA as Technical Note No.56 in 1921. Yerly production of aeroplane engines is quoted as follows.

Period ............... Stationary engines ... Rotary engines ... Total
----------------------------------------------------------------------
August to December 1914 .............. 748 .................. 100 .......... 848
January to December 1915 ............ 4544 .................. 493 ........ 5037
January to December 1916 ............ 6930 .................. 892 ........ 7822
January to December 1917 ........... 10364 ................. 836 ....... 11200
January to December 1918 ........... 13757 ................ 1785 ....... 15542
-----------------------------------------------------------------------
Total ........................................ 36343 ................ 4106 ...... 40449

Regards,
Yavor

[Dan_San_Abbott]

Hi Dave:
When the Flugzeugmeisterei ordered aircraft, they also ordered spare engines at some ratio to the some number of aircraft to furnished to the units in the field. This allocation would be through Motorenbau Abteilung, (Moba) who were reponsible for furnishing engines to the aircraft factories. What I am curious about, is whether BMWIIIa furnished to The Jagdstaffeln i the field. What got me thinking about this the BMWIIIa engines that were sent Fokker twice. Either an engine was taken out of a wreck or the engine had been replaced as being worn or damaged, whatever. I have never seen the spares requirements for engines aside from the Engine Repair Kit. I would think the engines would be held at Armee Flugpark. This is turning into a very interesting thread.
Blue skies Dave,
Dan-San