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CD ScaleDesigns Albatros CI build

Old 01-11-2011, 10:39 AM
  #1801  
abufletcher
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Default RE: CD ScaleDesigns Albatros CI build


ORIGINAL: TFF
There is another reason to offset the cylinders which just came to mind; it can help with wear on the cylinder walls.
There was something in the patent about this. Here's another diagram that came up in a search for "offset cylinders."


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Old 01-11-2011, 10:51 AM
  #1802  
geezeraviation
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Default RE: CD ScaleDesigns Albatros CI build

It really is all about torque improvement and it makes sense to do it to an aircraft engine in a time when overly powerful engines were just a few developmental years away.
Doc
Old 01-11-2011, 11:45 AM
  #1803  
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Default RE: CD ScaleDesigns Albatros CI build

Okay,
Here is the engine manual, although it is for the DIVa engine, sorry, it's all I've got. Even though it is a latter version the design might have remained very similar. How's your German? The manual is in German of course, I hope you can read it as it might explain any cylinder offset in the text.

There are two useful diagrams - but they may only add to your conundrum. The left hand sketch shows a slight offset whereas the right hand profile seems centered. Maybe the text of the manual will enlighten us all.
I will keep searching for other info.

Good luck,
Brian

Too large a file to attach the manual, here is the link
http://home.comcast.net/~shademaker/DIVa.pdf
from the Aerodrome Forum
http://www.theaerodrome.com/forum/ai...ne-manual.html

Might this be of help?
Daimler Motor Mercedes 160 & 180 HP 1914-1918 general arrangement and detail drawings - 2 sheets full of dimensions and technical descriptions. Drawn 60+ years ago by W. A. Wylam 1947 with assistance from Msrs G. D. Angle & E. H. Sherbondy.
http://web.me.com/blairsaam/eBayAuct...1813_29338.jpg

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Old 01-11-2011, 12:13 PM
  #1804  
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Default RE: CD ScaleDesigns Albatros CI build

I would be very surprised that in 1916-17 that the engineers with their early understanding of internal combustion could perceive an advantage in having the crankshaft offset.
Old 01-11-2011, 12:49 PM
  #1805  
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Default RE: CD ScaleDesigns Albatros CI build

I sure wouldnt short change them, Leverage and angles are the things power advantage is made of and I'm sure they were smart enough to know it.
Doc
Old 01-11-2011, 02:06 PM
  #1806  
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Default RE: CD ScaleDesigns Albatros CI build

Does this schematic of the Mercedes DIIIa help? I found it but don't have time to check the symmetry.
Located here:
http://www.aeroscale.co.uk/modules.p...=102665&page=1

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Old 01-11-2011, 02:11 PM
  #1807  
BobH
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Default RE: CD ScaleDesigns Albatros CI build

The Disadvantage of an offset crank shaft is uneven wear on the cylinder. The cylinders become elliptical over time due to uneven forces.

Were I a betting man I'd wager that the error is in the drawins and not in the original design.
Old 01-11-2011, 02:29 PM
  #1808  
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Default RE: CD ScaleDesigns Albatros CI build

Bob all cylinders wear in an oval pattern due to the awful centrifugal forces involved in throwing an offset crank throw with an iron conrod bolted to it while shoving and tugging on the piston, which accelerates and decelerates at incredible rates during the engine cycle. Heres a picture of a bore guage used to check cylinder taper and out of round, a basic check before overhauling any engine. Sorry if it looks well used.
Doc
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Old 01-11-2011, 02:36 PM
  #1809  
BobH
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Default RE: CD ScaleDesigns Albatros CI build

Geez thanks for posting. I do know that all cylinders get out of round.. to some it happens sooner and more pronounced due to their design.
Old 01-11-2011, 05:47 PM
  #1810  
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Default RE: CD ScaleDesigns Albatros CI build

People were smarter than we think "in the past." Here's astronomical calculating device created hundreds of years before the Greeks supposedly came up with the idea (about 100BC).

http://apod.nasa.gov/apod/ap110109.html

If I can't find evidence that the offset cylinders are wrong, the right thing to do as an "archivist" is to keep this feature. Plus, it's a bit of a novelty. But since actually instances of the Benz Bz III still exist, it would be a simple matter of just looking at one to discover the truth.

Brian, thanks for the Daimler manual. I'll see if I can skim through it for clues later today.
Old 01-11-2011, 07:32 PM
  #1811  
BobH
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Default RE: CD ScaleDesigns Albatros CI build

Don, take a look at this site and pay particular attention to the engine.

http://www.largescaleplanes.com/revi...2002/32002.php
Old 01-11-2011, 07:32 PM
  #1812  
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Default RE: CD ScaleDesigns Albatros CI build

In a quick scan through the text of the DIV manual I didn't see any suggestion that the cylinders were off-center. But then on that engine they don't appear to be.

This is the closest to a straight-on photo as I'm likely to find. And it's hard to say.
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Old 01-11-2011, 08:29 PM
  #1813  
BobH
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Default RE: CD ScaleDesigns Albatros CI build

The other Benz engines Ive looked at have centered cylinders so I just cant imagine the bzIII being the odd duck. Just makes no sense to me..
Old 01-11-2011, 09:19 PM
  #1814  
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Default RE: CD ScaleDesigns Albatros CI build

Make that "2 odd ducks"
From this source (which is Arizona Models and so now I am LOL) it appears that both the Benz 100 and the Benz 150 had offset cylinders! Check out the diagrams.
http://www.finemodelworks.com/arizon...Benz/Benz.html

These diagrams are however what I call drafted "sketches" because they contain both errors and simplifications! You must check and recheck against photos if you use them. You can see the Benz BzIV sketch for my engine and I believe the sketch reference for your BZ III engine. They provide a good starting point but for my purposes a much more detailed engine plan was needed. Luckily I found one. So if this is "all there is" for engine documentation then you go with what the diagrams are telling you - now their are two engines with offset cylinders. And in the fast & quick evolution of engine design the offset cylinders were abandoned for the design of the BzIV.

I was trying to help, didn't really mean to do this to you... Maybe email the museum curator and have them take a photo straight on for you to analyse.

What to do eh!
You've uncovered quite a mystery here Don. If offset cylinders are for real then you have quite a unique engine to model. If the offset is erroneous then you still have a nifty engine to model...

Are you still enjoying this?
Cheers,
Brian
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Old 01-11-2011, 10:21 PM
  #1815  
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Default RE: CD ScaleDesigns Albatros CI build

ORIGINAL: Flying Fox
From this source (which is Arizona Models and so now I am LOL) it appears that both the Benz 100 and the Benz 150 had offset cylinders! Check out the diagrams.
Thanks for reminding me of this page. Of course, there's nothing wrong with linking to AM since basically everything on their site is "acquired" from someplace else. The drawings are similar to the Baubeschreibung ("building description") drawings which apparently were part of the bureaucracy of WWI aircraft production. They were like "reference cards" where certain required information could be looked up quickly. They are similar also to old-time patent drawings, in that they gave enough info to support the patent claim but often not enough information to "give everything away."

Seeing that there are two of these off-set engines by Benz, which would amount to two drafting errors (of a serious sort) on two different documents, I think I should go ahead and do the offset cylinders on my model.

You've uncovered quite a mystery here Don. If offset cylinders are for real then you have quite a unique engine to model. If the offset is erroneous then you still have a nifty engine to model...
I hate to say I live for moments like this, but, yes, such "noticings" are fun! Whether it's ultimately correct with have to be for someone else to eventually determine. Maybe next time someone happens to be in Krakaw museum, they'll think of "Crazy ol' Don on RCU" and decided to take a photo...and then post it online somewhere. And our grandchildren's grandchildren will wonder how anyone could not have know such basic core information about the world!
Old 01-12-2011, 12:12 AM
  #1816  
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Default RE: CD ScaleDesigns Albatros CI build

Here's another rotated shot of the Benz in the Krakaw C1. The rocker rods are missing on this engine, but again there's little to suggest an offset to the cylinders. One important thing to note however, is that the first cylinder sits well ahead of the first former. Now, I wonder...the flat milled top of the crankcase was most definitely asymmetrical, curving smoothly up on the left but with the extensions for the rocker rods on the right. Could this have fooled the original sketch artist? Did one artist produce both of the sketches with the offset cylinders?

(Did "ancient astronauts" really visit the Nazca plains of Peru?)
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Old 01-12-2011, 12:43 AM
  #1817  
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Default RE: CD ScaleDesigns Albatros CI build

Don, I have the huge Jane's Fighting Aircraft of World War 1 which is basically a reprint of several Flight articles, which also has a lot on the Benz 230 HP Engine including scale (dimensioned!) drawings. I'm not sure if this is the one you're looking at, but at a quick glance it seems to be the same. The cylinders were certainly NOT offset. I have a big presentation this afternoon, so can't scan the drawings for you right now, maybe later this eveninig. Chris
Old 01-12-2011, 01:02 AM
  #1818  
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Default RE: CD ScaleDesigns Albatros CI build

Here's an explanation of the utility of an offset cylinder:

http://www.insightcentral.net/encycl.../enoffset.html
Old 01-12-2011, 01:03 AM
  #1819  
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Default RE: CD ScaleDesigns Albatros CI build


ORIGINAL: CTDavies

Don, I have the huge Jane's Fighting Aircraft of World War 1 which is basically a reprint of several Flight articles, which also has a lot on the Benz 230 HP Engine including scale (dimensioned!) drawings. I'm not sure if this is the one you're looking at, but at a quick glance it seems to be the same. The cylinders were certainly NOT offset. I have a big presentation this afternoon, so can't scan the drawings for you right now, maybe later this eveninig. Chris
Now I'm really confused! The info Flying Fox forwarded have me convinced the engines have cylinders offset towards the cam shaft to the amount of 10mm asdimensioned on one of the drawings. This certainly seems deliberate and not an artifact of some reproduction process.

Russ
Old 01-12-2011, 01:12 AM
  #1820  
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Default RE: CD ScaleDesigns Albatros CI build


Back in the dispute, I approach the argument from the perspective of an "ancient" draughtsman: Although the drawings are done in a rather crude manner but they are accompanied by the size, this would mean that the measurements are carried out effectively.
It may be inferred therefore that there is actually the offset of the cylinders, the photographs shown are unlikely to help because of the effect of perspective, would require a photo taken in front of or from, I remember the curator of the Museum of Kracovia as a person very nice and helpful so it might be the case ask him .......
Old 01-12-2011, 01:15 AM
  #1821  
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Default RE: CD ScaleDesigns Albatros CI build

For you hardcore engineers out there. Here is proof that offset piston/crankshaft designs exist and have been seriously studied. 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 (and also on the Mercedes engines). This really boils down to basic geometry of forces and this stuff would have been obvious to engine designers back in WWI.

One of the conclusions:

"The offset crankshaft engine decreases the side thrust force, when compared with the conventional engine but it has a smaller torque."
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Old 01-12-2011, 01:23 AM
  #1822  
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Default RE: CD ScaleDesigns Albatros CI build



The offset would also seem to reduce piston and cylinder wear. Do you suppose this is why they were designed that way?

Russ

Old 01-12-2011, 01:30 AM
  #1823  
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Default RE: CD ScaleDesigns Albatros CI build

More fuel for the fire: The Anzani 6 apparently had on offset to the cylinders relative to the center point. Such an offset was referred to as "désaxé." So this design concept was well-known even before the war!

http://en.wikipedia.org/wiki/Anzani_6
Old 01-12-2011, 01:39 AM
  #1824  
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Default RE: CD ScaleDesigns Albatros CI build

So that does it for me! Back to work on the dummy...with it's offset cylinders.
Old 01-12-2011, 01:44 AM
  #1825  
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Default RE: CD ScaleDesigns Albatros CI build

ORIGINAL: BobH
Don, take a look at this site and pay particular attention to the engine.
http://www.largescaleplanes.com/revi...2002/32002.php
That's a Benz IV and the cylinders were inline. BTW, those Wingnut kits look gorgeous. I don't want to actually build one, but they look like a great reference for any scale builder.

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