Teus

Just found some photos from a Daimler D-IIIa at [link=http://www.jasta11.co.uk/page13.htm]THIS[/link] site. If you take a good look at the crankcase it seems both sides are equal.

abufletcher

That's an interesting site. But it's not a Benz. The Daimler D-III looks the same as the Mercedes DIII (licensed production?).

CTDavies

This is what was described in Flight as a 230 HP Benz Engine. It looks like what's labelled at 200 hp Benz on the Arizona page. Is this what later became known as a Benz IV?

abufletcher

Yeah, that's the Benz IV, which is a substantially revised engine. Great drawings though! Maybe these are the "better" ones that Flying Fox mentioned.

Mein Duff

Teus, thanks for linking that WWI site, some great info. and excellent photos of old and new projects.
I am continully amazed at the knowledge and ingenuity of the early pioneers of flight, just acknowledging the amount of industry and engineering that went into these early engines with the primitive tools they had is humbling.

CTDavies

Yeah, I had just posted those images, when I realized that the cylinders are totally different. [link=http://www.thomasgenth.de/html/albatros_c_i.html]This[/link] website says the Albatros CI in Kracow (sp?) has a 150hp Benz III.

Flying Fox

For me all this adds up to a "yes" the cylinders on the Benz Bz III (as well as the earlier engine) probably were offset but the design was abandoned on later Benz engines Great sleuthing Don
this is what the scale hobby ias all about, especially for us WWI fans.

I attach a page of a report from the Journal of American Society of Navel Engineers on the 170 Horsepower Mercedes Aviation Motor. Three lines down it states, "This motor is of the fixed vertical type, six cylinders in line, which are not-offset and is water cooled. This is not your engine but it further helps prove the fact that offset engines existed.

Good show Don, I heartily agree with you. The research done by you and others has proven that offset cylinder engine concept was real and existed on several WWI era engines. This forum certainly has a wealth of expertise at its fingertips.
You have a really neat engine to model in the Benz Bz III with its offset cylinders!

Cheers and good luck - we await your work on the Benz II offset engine!
Brian

abufletcher

That pretty much nails it.

Mein Duff

Great sleuthing on your part also Brian ! This just gets more and more interesting....we are indeed very fortunate to have such a wealth of knowledge on our team and at our fingertips these days.
NOW does anyone out ther have any detailed info on the Woseley Viper engine???? I have lots on the Hispano Suisa but have never found much on the Woseley for my SE5.

TFF

It took some doing but now I have my engines straight. Daimler/ Mercedes engines have overhead camshaft driven from the back of the engine. Benz engines are pushrod engines. Austro-Daimler engines are overhead cam driven from the front of the engines. Daimler/Mercedes and Benz merged in 1926, worked together from 1924, tried to merge in 1919, and were competitors before. Now the pictures of each make more sense.

Flying Fox

Chris,

Is this what later became known as a Benz IV Yes indeed it is the Benz Bz IV 230 HP aero engine - with a straight inline six and no offset. In fact it is the very engine I am modelling for my 1/6 scale LVG CVI. I intend to model an exact scale replica - at least to the best my limited skills will allow.

I am glad you have found those drawings. I have something very similar but without the dimensions. I just laid out $35 US for a download of an Engineering Journal report on the engine. Disappointedly the resolution of the diagrams is too low to show the diminsional numbers. It contains valuable info but I was really hoping for the dimensioned diagrams.[:@]

So thanks a bunch for your scans, they will further compliment my documentation and scale build. If you have higher res scans of those diagrams might you PM tham to me? You might have viewed my build on this forum: Benz Bz IV - 1/6 scale engine scratch build.

Attached below is what I have...

Cheers,
Brian

abufletcher

Here's what I've got to work with in terms of space. It's a shame, now that we've found out so much about the engine, not really to be able to model it. And this probably already puts the base of the cylinders about 5-6mm above their scale position. And of course, there won't be any space for the area of the "crankcase" ahead of the first cylinder. And there's no point in doing anything behind the last cylinder. This would really just be a base onto which I can attach the cylinders (and the whole unit would be removable to access the tank area). But at least we'll see that cylinder offset! Of course, I could "fudge" the cowls just slightly to hide the extra height. Basically, the position looks good. Compare the last crop from one of the Krakaw photos with the position relative to the strut in the photo of my model.

PS. Brian, I think I also ended up at that same archive for the Naval Engineering documents, but was too cheap to order anything!

abufletcher

The DF drawings show the Mercedes engine, but one of the color profiles on the back shows the Benz.

TFF

I would shorten the base by the amount over. With the full cowl you wont be able to see the base anyway and fudging the outline is not what you do.

abufletcher

So true, so true! I suppose more than anything I'm afraid of not being able to get them all level again. So, now that you can see how it would fit over the engine mount (and tank area) what do you think about a mounting method for the cylinders?

John Cole

My Feedback: (4)

Hi Don,

When I build 6cyl in-lines, I start with a base plate from plywood. Holes are carefully cut to allow a slip fit for the cylinders. They can then be aligned before bonding in place. This setup allows fillets of epoxy on both sides of the plate. The plate can be shock mounted, or not. The cylinders are also tied together across the top with the cam housing, water pipes, etc. Structural integrity is important for model longevity. Another technique is running screws (with epoxy) up through the bottom plate, but I've not done this myself.

Once complete, the base can be painted dark grey or black. With the cowl installed, the effect is nice.

Your project is looking great!

John

TFF

I think glue and screws from the bottom might be the best. Just make sure they go deep into the cylinder. The screws dont have to be large diameter just long.

abufletcher

So is the consensus that I shouldn't hollow the cylinders out (to lighten them)? A present each weighs about 36g and hollowed out they are 21g. If I don't hollow them out, I would estimate the total weight of the dummy will be upwards of 400g.

geezeraviation

My Feedback: (3)

I would think the thing to do would be to assemble as much as you can and get an idea of how well (or not) balanced it is so you know if the weight is going to be needed. If fit is you may need to hollow them to add lead if not they may be ok or need hollowed.
Doc

John Cole

My Feedback: (4)

You will likely need the weight anyway.

J

Flying Fox

Don,
It was a bit of a waste of money on the report as I already had the written info and was hoping to acquire the diagrams. Bit of an inpulse purchase[:@]. Chris's scans in an earlier post are excellent and compliment my documentation. Thanks Chris.

John Cole's idea sounds good. Yes, it is an issue of how to maintain structural integrity both in terms of outline and strength.
Perhaps consider hollowing out cylinders as planned to decrease weight. Cut thin circular disks to glue to the baseplate. The engine cylinders fit nice onto the wood disks on the baseplate. Use slow curing epoxy to glue it up and check/adjust the allinment of cylinders.

Looking great - I'm sure you will get it just right.
Cheers
Brian

abufletcher

Thanks for all the suggestions. Maybe a combination of several of those ideas will work! Here's my thinking at the moment. I'd like to keep the dummy as light as possible for several reasons. First, a heavier dummy might be more prone to being "shaken apart." Second, I will almost certainly have to add weight. But I'd rather pack the weight in as far forward as possible and lower down.

So...I'm tempted to go ahead and hollow out the cylinders. Then use the wooden plug on the ply plate trick, perhaps with a screw into the plug. I think I'll probably decide to trim off the base flange to lower the position a tad. And, yeah, the cylinders will end up glued to each other as well. I'm assuming that epoxy bonds well with resin.

Brian, I had my "finger on the button" to buy the article too! But managed to resist.

abufletcher

Hollowing out the cylinders reduced them from 36.5g to 23g each, so the total for 6 cylinders (and I have two "spares") is 137g. They have been bored to a depth of about 45mm, which is just above the "cooling" bands.

Flying Fox

That's about a 35% weight reduction per cylinder isn't it? - nice.
Balsa - what an amazing wood, so many uses including hi-tech clamping devices.[&:] Don I can't help but envy those resin cylinders every time I look at them. Sure is going to make your finishing detailing a whole lot easier.
Keep up the great work!
Brian

TFF

How delicate is the casting resin? If fine details like fins on a aircooled cylinder were cast, would they survive normal use or is it too brittle?