A Wright Cyclone has a circular crankcase and pushrod tubes in front of each cylinder. The cylinder barrels are also much shorter than on the engine Marcel has posted which has an angular crankcase very much like the photo in post #17 though the crankcase bolts are smaller and not counter-sunk.
Aircraft engine
- Thread starter Marcel
- Start date
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A Wright Cyclone has a circular crankcase and pushrod tubes in front of each cylinder. The cylinder barrels are also much shorter than on the engine Marcel has posted which has an angular crankcase very much like the photo in post #17 though the crankcase bolts are smaller and not counter-sunk.
Can I suggest that it could be the other Bristol engine of the era?
The Bristol Mercury - which was the more compact, shorter stroke - thus smaller cylinder engine
Apart from anything else, it was the power plant of the Blenheims - note the counterweights!
But then, both the Hampden and Wellington had the Pegasus - so statistically speaking it is probably a Pegasus!
So, I vote for a Bristol radial of some sort. The Pegasus had a longer stroke, so presumably longer cylinders. To settle on which one you would have to take measurements I suspect.
Michael Hope
Airman 1st Class
- 228
- Jun 28, 2016
The propeller in the above image has the wrong rotation compared to original pictures. If you compare the location of the large weight slug on the counterweight bracket these images have on the opposite side of the blade.
- Thread starter
- #26
Actually, the Mercury was my first guess, as it was the main engine used by the Dutch airforce, making it even a more likely candidate, but as already shown, the cylinders don't match unfortunately. I agree with you in that I think it's a bristol. Everything on this screams to me it's a Bristol, but I don't have substantial prove, although it's satisfying to me that most of you seem to think in the same direction as I do.
Meanwhile I've been searching for reports of found engines in the waddenzee, but came up dry sofar, there are so many, but none mention Lauwersoog.
For guys with eyes for the right details, do you think this might be a similar engine? I'm not technical enbough to look for the right details. This is an engine at the bunker museum on Schiermonnikoog, the island close by Lauwersoog:
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What is this engine?
MiTasol
1st Lieutenant
The first photo shows a planetary reduction gear
MiTasol
1st Lieutenant
Hi Yakman
Dissimilar metal corrosion, especially in salt water, will dissolve the aluminium heads over time.
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MiTasol
1st Lieutenant
It is most definitely not a sleeve valve as there are no ports half way up the cylinders.
Having worked on both the Pegasus and the Mercury I would put money on one of those two because the crankcase through bolt screams Bristol.
A couple of better photos or some measurements would be needed to get more exact
Mi
YakMan
Airman
Dear MITasol, you are absolutely right - I hadn't thought of that. It totally explains why all cylinder heads are neatly missing and also the entire crankcase between the main core and propeller hub exposing the reduction gear!
Thanks!
YakMan
Airman
Dear Marcel,
From juggling between the photos I think the photo above is the same engine as the quayside engine. The amount and location (thanks MITasol) of corrosion looks to be identical, there seem to be four groups of four studs holding down each pot of which the finning looks very similar. Similar reduction gear, similar propeller hub. Would not say definitely but the two share an awful lot.
Cheers, YakMan
- Thread starter
- #35
The photo in front of the engine at Schiermonnikoog seems to show a Hampden. I'm not quite sure as the resolution is really low. If that's the case and the engine comes from said aircraft, the engine must be a Bristol Pegasus.
I've gotten a few inquiries running, so I hope I'll get some answers soon.
I've gotten a few inquiries running, so I hope I'll get some answers soon.
Doesn't look like a Pegasus to me.
Different crankcase (which appears to be alloy too) and which also has pushrod tubes. The engine you are asking about has a steel crankcase and no sign of having pushrods fitted.
Different crankcase (which appears to be alloy too) and which also has pushrod tubes. The engine you are asking about has a steel crankcase and no sign of having pushrods fitted.
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MiTasol
1st Lieutenant
Re post 31
I still think it is a Bristol but after thinking overnight there are too many cylinder hold down studs for the Mercury and Pegasus models that I worked on. One had 8 studs from memory (Mercury I think) and the Pegasus II M 3 had twelve studs from memory. If I could find my II M 3 manual I would put up pages from that. That said the later Mercury or Pegasus may well have had more studs to allow for higher boost and power settings.
The Bristols all had long reduction gear housings to provide space for the collector exhaust and in these photos it is hard to tell how long the reduction gear is but I am beginning to feel that it is too short.
I will keep looking for that #$%^& manual
I still think it is a Bristol but after thinking overnight there are too many cylinder hold down studs for the Mercury and Pegasus models that I worked on. One had 8 studs from memory (Mercury I think) and the Pegasus II M 3 had twelve studs from memory. If I could find my II M 3 manual I would put up pages from that. That said the later Mercury or Pegasus may well have had more studs to allow for higher boost and power settings.
The Bristols all had long reduction gear housings to provide space for the collector exhaust and in these photos it is hard to tell how long the reduction gear is but I am beginning to feel that it is too short.
I will keep looking for that #$%^& manual
MiTasol
1st Lieutenant
Gidday Marcel
I think you have got it as the crankcase through bolts are the same, the cylinder hold down studs are the same and the prop has the same unusual domed counterweights and spinner.
Interestingly your photo shows a front ignition harness which none of the Bristols I worked on had so that strongly suggests it is not a Bristol unless a different submodel.
Now I am inclined towards it being another make of engine and one engine that was very common in Europe in many guises was the Pratt and Whitney Hornet. As well as imports, that was also built under licence by BMW and Fiat. BMW later developed the BMW 132 from the Hornet.
A quick web search shows the Hornet also had a front ignition harness in some variants and that at least one model BMW 132 had both the "Bristol" crankcase studs and front ignition harness.
Maybe someone with some real knowledge of the BMW 132 (my knowledge is limited to this mornings web search) could look at Marcel's photos in posts 1 and 26 and provide knowledgeable comment. The engine was used in the Arado Ar196 float-plane and that had a spinner so I would very very hesitantly suggest that is a possibility for both the engine and aircraft it came from. A number of other German airframes used this engine so it was relatively common.
Mi
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YakMan
Airman
Yea, thats weird - a steel crankcase?? I don't know of any. That would make the core incredibly heavy. I would be tempted to suggest a tank engine (if it didn't have a propeller dangling off the front!!) so I won't even say it
MiTasol
1st Lieutenant
Forged steel crank cases were not uncommon before high strength forgeable alloys were developed (most, if not all, rotary engines used steel crankcases) and in the case of the Wright R-1820 the early engines were forged aluminium but starting at the G100 Wright reverted to forged steel. My guess is that the power increase outstripped the alloy technology at that point. If memory is correct the much later engines reverted to forged alloy. I discarded the R-1820 as I can not think of any 1820 installations with spinners except the Buffalo and as far as I know they were not operating in that area.
Cast aluminium and forged aluminium will corrode differently due to the density and different alloying materials so I did not discard the case being made of forged alloy. I could well be wrong.
My exposure to Hornet engines is minimal but I have a memory that some of them also used steel crankcases and that would probably have followed through to the BMW.
Likewise some European engines used steel cases - Hispano Suiza comes to mind as did at least one Japanese engine.
And Marcel's engine is definitely not a Bristol Mercury or Pegasus. I should have picked up on this on day one - the Bristol Mercury and Pegasus both used a beveled epicyclic reduction gears. This engine has a planetary reduction gear.
If anyone knows how to invite Shortround6 and/or Callum Douglas and/or William Pearce into this discussion I am sure a quick result would emerge
Cast aluminium and forged aluminium will corrode differently due to the density and different alloying materials so I did not discard the case being made of forged alloy. I could well be wrong.
My exposure to Hornet engines is minimal but I have a memory that some of them also used steel crankcases and that would probably have followed through to the BMW.
Likewise some European engines used steel cases - Hispano Suiza comes to mind as did at least one Japanese engine.
And Marcel's engine is definitely not a Bristol Mercury or Pegasus. I should have picked up on this on day one - the Bristol Mercury and Pegasus both used a beveled epicyclic reduction gears. This engine has a planetary reduction gear.
If anyone knows how to invite Shortround6 and/or Callum Douglas and/or William Pearce into this discussion I am sure a quick result would emerge
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