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1999 Closed threads from 1999 (read only)

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Old 23 November 1999, 02:45 PM   #1
Lee E. Branch
Posts: n/a

I have a quote at hand re. the DVII: "..the BMW engine vastly improved its performance, virtually halving the climbing time to 5,000 meters from 31.5 minutes with the Mercedes to 16 minutes." I know only of M-B powered "booty" DVIIs here as used in U.S.A.A.S. and U.S.M.C. Many here, I'm sure, are aware of the unusual clause in the "Treaty of Versailles" which specifys the surrender of that one type of airplane. I don't think they, the Germans, were manipulating to nullify any "advanced technology transfer" that would have occured, since some BMW powered ships were downed and salvaged late in the war. I'm just curious as to why the most impressive performers among the DVIIs didn't seem to arrive in this country. We did use them to supplement our own Air Service so why not import the really advanced BMW version? I've read that Boeing among other manufacturers were given examples of DVIIs to study: This latter point seems to suggest that the steel-tube structural features was of more paramount interest. It seems an oversight here if the factor of fighting performance (engine) superiority was subordinated to the interest in fuselage fabrication technique. Anyone have a study handy on "booty" DVIIs that might clarify this? VBR. Lee
Old 24 November 1999, 08:11 PM   #2
Dave Watts
Posts: n/a

Hi Lee,

Take a look at "FOKKER D.VII in action" by D. Edgar Brannon. This is the book that almost everyone has. It's a "squadron/signal publication". Most of the photos came from Pete Bowers. If you look on page 38, it shows a photo of "142 Fokker D.VIIs for American Forces war booty". The first aircraft in the photo is Fokker D.VII F 7755/18. According to the official army acceptance for this aircraft, it was accepted on October 26th, 1918 and had BMW motor Nr.1618 installed.

On page 40 you can see Fokker D.VII 7756/18 at Kelly Field. This was Mercedes powered.

On page 38, bottom, is a line up of D.VIIs at Kelly Field. You can see the first two D.VIIs are serial numbers, D.VII F 7784/18 and D.VII F 7785/18.

D.VII F 7784/18 was accepted on November 16th, 1918 and carried BMW motor Nr.1669.

D.VII F 7785/1818 was accepted on November 26th, 1918 and carried BMW motor Nr.1644.

Yes, I have the dates correctly transcribed from the acceptance sheets.

Based on this information, you can see that the U.S. did indeed have some BMW powered examples of the D.VII available for testing. It makes sense that most of the D.VIIs brought back were the very latest version, often never having seen action.

Very Best,
Old 25 November 1999, 11:38 AM   #3
lee edw.branch
Posts: n/a

Thank you Dave. It is interesting that DVIIs with successive serial #s seen to have either engine. Have I interpreted the #s correctly (ie. as "factory #s) or are they "U.S. acceptance #s"?. I wonder why the far less powerful ships were brought in at all? The most rational decision would have been to bring in the BMW version with it's radically superior level of performance.
I've seen a few Mercedes. Jim Appleby usually had two or so around here. Chuck Wentworth and Javier A. usually have an several on hand; I've never seen or heard of the BMW in private hands though. Any in museums anywhere? Not that I need to know but I have always been interested in the non-appearance of them among the D-VIIs I've been aware of. One of the oddities re DVII powerplants was to see the "Hisso" in the Paul Mantz owned DVII during his years as a museum operator and source of motion picture a/c. He converted it I believe in the late '30s. It was annoying to see it. You'd think he'd have other uses for the Hisso as well as other options for the VII. I understand one version of the Hall-Scotts had cylinders interchangeable with the Mercedes. Maybe the ready availability of such H-S "top-end parts" influenced the decision of buyers of surplus VIIs to chose the M-B engined ships. I know some DVIIs were re-engineered in the '20s and '30s with the H-S.Did you encounter the name Charles Cash, of Memphis, Tennessee in your accumulation of lore and parts on the VII? He had a life long interest in them and sent me some very interesting photos at one time. Do you have Herb Kelley's present address? He is in a rest home somewhere. He'd love to hear from you I'm sure. Herb's drawings probably had a great deal to do, I'd venture to say, with creating interest among DVII replica builders through the '60 and '70s. Are you complete and flyable? Featured in any mags that I might be able to acquire?
As I said in a prior e-mail to you "always enjoy your input to the Forum". Also may I add to the many well-deserved compliments you've received re. the "Spandau" article in "WWI Aeroplane". Cordially yours, LEB
Old 28 November 1999, 04:49 PM   #4
Dave Watts
Posts: n/a

Hi Lee,

You observed that successive serial # D.VIIs have either engine.

That is correct. The lion's share of all BMW motors went to Fokker, but this was still far short of the production demand for motors that Fokker had with the D.VII, (as well licensed built D.VIIs at Albatros, or Albatros O.A.W.). What you find when you study the German Army acceptance sheets for Fokker and compare them with the Daimler Mercedes shipment logs, is that many overhauled and rebuilt very "early", (as compared with new production), Mercedes motors were being utilized for D.VII production demands. This sometimes resulted in very late production D.VIIs with "early" Mercedes D.III, (not D.IIIa, or D.IIIau), rebuilt motors.

As to why weren't all of the D.VIIs that were brought back to the states, the BMW powered examples. I speculate that when the aircraft were rounded up for shipment to the United States, that the US Army may not have been that astute with regards to the motor difference, and didn't discover the discrepancy in performance until the aircraft were tested in the states.

As to the Mercedes being common, I wouldn't say that, but as compared to surviving BMW motors, I guess you could say so. I can count the surviving privately owned Mercedes motors in the US on my two hands.

Javier has, (the last I knew of), three plus parts;
Two motors plus parts from Jan Miller in Detroit, via Ken Hyde, via Strahler in Stuttgart. His other motor came from a Vancautern in Belgium. I had been conversing with him for years, and when he was ready to sell, I hooked him up with Frank Ryder, and had a best friend go inspect, pickup, clean, and ship it to Atlanta for Frank. Javier/Chuck got it from the Ryder estate. I still have the 1918 rebuild tag from Aachen for the motor.

I don't know of any BMW motors in private hands either.

Out of the nearly 2700 D.VIIs produced, most likely only 500 or so had the BMW installed. This gives a 4:1 ratio of Mercedes to BMW, but there certainly where more BMW D.VIIs later in the war, perhaps 3:1. You have to remember that it can be shown in the acceptance sheets where a individual BMW was installed in as many as four different D.VIIs. They continually recycled the motors.

The problem you have with these motors versus rotaries, is the water cooled in line motors could be utilized as good powerplants for other applications. These motors tended to be used for everything from boat motors to water pumps. They were usually used till they wore out. Whereas rotaries on the other hand were immediately outdated after the war by radial motors. And with radials, you didn't have to have caster oil fuel. The last major thing is, if you were to take a BMW and a LeRhone off of aircraft and throw them into a barn for fifty years, you would find that the BMW may look good from the outside, but have corrosion inside the crankcase and cylinders, and the water jackets are rusted through, whereas with the rotary, you would find that the outside of the motor may have some light rust, but the castor fuel has left a protective coating on the inside of the motor, like a preservative and it is perfectly fine. This was not always the case, but it certainly makes the point clear. The rotaries couldn't be utilized nearly as easy for stationary powerplants for other applications.

Yes, Charles Cash is one of the early forefathers of serious documentation and study of the D.VII. I have talked with him a few times. Herb Kelly, I have written with many times, I was interested in the Fokker V.1 years ago, and loaned him material for the drawing he made.

I am still assembling my project, I just got a AXIAL prop from the Berlin museum this week. It's for my Mercedes, and looks great. I was quite excited to receive it.

Thanks for the compliment on the Spandau article. If you have any opportunities to inspect some examples of the Spandau, I would be most interested, and could give you a toll free phone number to call me with your observations.

Very Best Wishes,


fokker, dviis, surrendered

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