Author Topic: Benz Bz.III and Bz.IIIa Flugzeugmotor  (Read 2655 times)

Offline ColonelKrypton

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Re: Benz Bz.III and Bz.IIIa Flugzeugmotor
« Reply #15 on: July 24, 2021, 09:51:14 AM »
Thank you to all who have commented.

The manual that Willem was kind enough to provide is indeed for the Benz Bz.III motor.

A further search of the Krakow Muzeum web site and I have found similar manuals for the some of the Sechszylinder Benz Flugmotoren including the Bz.IV and what is referred to as the 200Ps ( hp ) engine and Sechszylinder Benz Flugmotoren type FB type FD and type FF

Benz used internal type ID's for some ( most or all ? ) of their motor as follows:

manufacturer's designation: Type FD    Bz.??    85-95 PS
manufacturer's designation: Type FD    Bz.II    100-110 PS    https://en.wikipedia.org/wiki/Benz_Bz.II
manufacturer's designation: Type FF    Bz.III   150 PS           https://en.wikipedia.org/wiki/Benz_Bz.IV

All of these manuals provide several nice drawings of the respective motor. However, the drawings in the 150Ps manual and the FB FD FF manual are very similar. It can be assumed that the drawings in the 150Ps manual are for the type FF  ( Bz.III ) motor but it is not clear which motor the drawings in the FB FD FF manual represent - they are very similar to the drawings in the 150Ps manual but have small differences, perhaps the type FD or early FF.

I have extracted these drawings from the 150Ps and FB FD FF manuals and made a few notes which I can provide in a .zip file if anyone is interested.

Unfortunately I have been unable to find similar images for the Bz.IIIa which is the variant I most interested in. The Bz.III and Bz.IIIa are only similar in that they were the same power. The Bz.III has it's intake and exhaust ports on the same ( left or port if you prefer ) side of the cylinders whereas the Bz.IIIa has it's intakes on the left ( or port if you prefer ) and exhaust on the right ( or starboard if you prefer ).

German motor designations follow a pretty simple pattern:

up to 80 PS x.0
80-100   PS x.I
100-120  PS x.II
120-150  PS x.III
150-250  PS x.IV
250-500  PS x.V

where the x is something related to the manufacturer i.e Bz for Benz or D ( I think ) for Mercedes

My interest in the Bz.IIIa is for a recent project of Hansa Brandenburg W.29. My current thinking is to build it like serial 2670 which was the one taken back to England, repainted ( apparently ), and marked with British roundels. The serial number indicates that the aeroplane was powered with a Bz.IIIa ( Windsock datafile 055 Brandenburg W.29 by Peter Grosz  page 32 ).

Pictures show that the exhaust manifold is clearly on the right side of the engine so it is clearly not Bz.III powered.

However, the radiator style is the same as on later W.33 Mercedes D.IIIa and D.IVa (page 13 picture 32 comments).

So, is it possible that 2670 was powered by Bz.IIIa or maybe D.IIIa or D.IVa ?

I have enlarged the few photo's I can find for 2670 that show any kind of upper engine detail and it really isn't clear but most likely not D.IVa.

My dilemma is that my kit of choice is an old 1/72 Meikraft W.29 limited run low pressure injection molded kit and the provided engine is little more than a lump of plastic and it will need to be replaced with something that looks reasonably correct.

What to do , what to do ;)

cheers, Graham



Offline ColonelKrypton

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Re: Benz Bz.III and Bz.IIIa Flugzeugmotor
« Reply #16 on: July 29, 2021, 12:49:03 AM »
Good day all,

For those that may have an interest, I found another interesting high quality period photo described as A Mercedes D 111Aü six-cylinder water-cooled inline engine (160 hp) is built into the fuselage of the Hansa Brandenburg W.12 at Naval Airfield de Mok. The aircraft was interned at Rottumeroog in 1918 and still has the German registration number N 84.

https://nimh-beeldbank.defensie.nl/foto-s/detail/5f54a703-e8b0-ad1e-d5d2-f9cd4e395b61

However, it looks more like a Benz Bz.III engine rather than a Mercedes D.111. The W.12 is noted to have been built with both powerplants as noted in the Wingnut Wings W.12 (early) kit details "The first 10 production aircraft ordered in January 1917 (numbers 1178 to 1187) were powered by the 150hp Benz Bz.III engine with a vertical ‘car type’ radiator in front of the engine."  It seems that N 84 is likely 1184 and one of these first 10 production aircraft.


cheers, Graham

Offline Rookie

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Re: Benz Bz.III and Bz.IIIa Flugzeugmotor
« Reply #17 on: July 29, 2021, 02:56:49 AM »
Hi Graham,

This is all valuable information.

Did you consider posting it in "The WWI Modelers' Reference Library" section under "Engines" on this forums' main page?

Willem

Offline RLWP

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Re: Benz Bz.III and Bz.IIIa Flugzeugmotor
« Reply #18 on: July 29, 2021, 03:03:13 AM »

However, it looks more like a Benz Bz.III engine rather than a Mercedes D.111.

cheers, Graham

It certainly does. The Mercedes has an overhead camshaft, the Benz has a camshaft in the crankcase and pushrods - which is what is in the picture

Richard
Hendon for flying - the fastest way to the ground!

Offline ColonelKrypton

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Re: Benz Bz.III and Bz.IIIa Flugzeugmotor
« Reply #19 on: July 29, 2021, 10:13:59 AM »
Hi Graham,

This is all valuable information.

Did you consider posting it in "The WWI Modelers' Reference Library" section under "Engines" on this forums' main page?

Willem

Yes I have but I am not yet that organized.

I also stumbled across another interesting web site which has a lot of engine information but mostly after 1925.  Some Pre 1925 stuff here:

https://www.enginehistory.org/Piston/Before1925/before_1925.shtml

but I am still not finding a lot on the Benz Bz.IIIa.

cheers, Graham

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Re: Benz Bz.III and Bz.IIIa Flugzeugmotor
« Reply #20 on: July 29, 2021, 05:01:09 PM »
Ah, ok.

Again, a great link Graham.

Keep them coming!

Willem