# What is it?



## bones140 (Jun 16, 2009)

This part has a VERY tenuous link to the world of boats. No more clues. The more eagle eyed among you may notice a defect!


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## BlythSpirit (Dec 17, 2006)

Presumably the template shows some kind of eccentric rotation and the 10 o'clock arm is sheared off!


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## Duncan112 (Dec 28, 2006)

The model behind rather gives it away!! I'd never have recognised it otherwise. For a bonus point, why do such devices always have an odd number of working parts?


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## bones140 (Jun 16, 2009)

BlythSpirit said:


> Presumably the template shows some kind of eccentric rotation and the 10 o'clock arm is sheared off!


Well spotted with regard to the defect. The defect actually is another mystery more of which later!


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## bones140 (Jun 16, 2009)

Duncan112 said:


> The model behind rather gives it away!! I'd never have recognised it otherwise. For a bonus point, why do such devices always have an odd number of working parts?


My guess is that an odd number provides for good primary balance?


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## Duncan112 (Dec 28, 2006)

Balance is one factor, but there are two others - once people have guessed what it is Ill try to explain (ie remember Mr Abernethy's explanation from class 2 at S Shields)


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## chadburn (Jun 2, 2008)

Radial Engine connecting rods. They did try Radial Engines in an Air Sea Rescue Launch to be used in the Far East during WW2 but found that the power for the blowers to pass air over the cylinders to keep the engines cool made the project just a one off.


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## OilJiver (Jun 30, 2014)

Odd number of cylinders same-same axial variant - reduction of pulse pressure.


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## chadburn (Jun 2, 2008)

Your link with the maritime world was not too far off Duncan. The vessel concerned if I remember correctly was around 112ft long and powered by 4 Bristol Hercules air cooled Radial Engines. It was built for the purpose of rescuing downed Airmen in the Pacific and the ability to remain 'on station' under the Bombing Streams to Japan. The vessel undertook extensive Trials here, it was found the drain caused by the electric motors to power the fans which cooled the Radial Engines affected the vessels overall performance. Meanwhile the RAF had initiated the convertion of a number of Fairmile D's into Long Range Rescue Craft (LRRC) and sent a number on their way to the Far East. They reached as far as the Suez Canal when the Americans dropped the A Bomb, the War in the East ended the Fairmiles were left at Suez to provide RAF Officers Quarters, the Hercules engined vessel was stripped out and the Hull either sold or scrapped?


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## Duncan112 (Dec 28, 2006)

Thanks, in fairness it was Chadburn that identified the link - I related it to the action of a Hele-Shaw pump - hydraulic motors as well as radial engines share the phenomenon of "Ghosting" where an extra cylinder appears to be there in the vibrational analysis. With an engine this is compounded on the four stroke cycle with alternate cylinders firing, with a 9 cyl engine the order is 1,3,5,7,9,2,4,6,8 - wouldnt work with a even number plus with an even number of cylinders you would always have two cylinders diametriically opposed which, as you point out would lead to undesirable vibrations. The old Bristol Aero Engine exhibition at the docks in Bristol had quite a bit of technical info on this - I understand the museum has been "Modernised" so no doubt the complex explanations have gone?


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## bones140 (Jun 16, 2009)

chadburn said:


> Radial Engine connecting rods. They did try Radial Engines in an Air Sea Rescue Launch to be used in the Far East during WW2 but found that the power for the blowers to pass air over the cylinders to keep the engines cool made the project just a one off.


Correct with identification Chadburn! They are indeed Radial Engine Connecting Rods. The rod in the 5 o'clock position is the 'master' rod with the eight remaining rods being 'slaves'. The engine is a Bristol Pegasus from a Sunderland Flying Boat (as I said very tenuous link). The complete assembly sits on a very short single journal crankshaft. The Sunderland was lost in a storm on the Milford Haven Estuary in 1940 and was found by divers untangling fishing nets and was a subject of a TV programme called Wreck Detectives. Parts of the Sunderland are now in the excellent Pembroke Dock Heritage Center (a recommended visit). The pilot of the Sunderland was Derek Martin who unfortunately died early this year aged 93. The mystery of the broken connecting rod is that the cylinder and piston were intact when the engine was stripped down. No damage was identified from a rod flailing around in the cylinder and Derek Martin did not report any defects on landing as the aircraft was operating correctly. No one can speculate how the rod was broken.

http://www.divetheworld.com/diving/warbirds/SunderlandT9044/index.htm

http://www.dailymail.co.uk/news/art...and-flying-boat-raised-seabed-65ft-waves.html

http://www.sunderlandtrust.com/


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## Pampas (Jul 2, 2008)

And here was I, at first glance thinking it was feathering gear for a small paddle wheel. How many others thought the same?


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## LouisB (Dec 23, 2007)

chadburn said:


> Your link with the maritime world was not too far off Duncan. The vessel concerned if I remember correctly was around 112ft long and powered by 4 Bristol Hercules air cooled Radial Engines. It was built for the purpose of rescuing downed Airmen in the Pacific and the ability to remain 'on station' under the Bombing Streams to Japan. The vessel undertook extensive Trials here, it was found the drain caused by the electric motors to power the fans which cooled the Radial Engines affected the vessels overall performance. Meanwhile the RAF had initiated the convertion of a number of Fairmile D's into Long Range Rescue Craft (LRRC) and sent a number on their way to the Far East. They reached as far as the Suez Canal when the Americans dropped the A Bomb, the War in the East ended the Fairmiles were left at Suez to provide RAF Officers Quarters, the Hercules engined vessel was stripped out and the Hull either sold or scrapped?


Well explained - filled in some of my questions regarding some of the inadequacies of radial engines when used outside their original general intent - thanks.

LouisB. (Scribe)


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## chadburn (Jun 2, 2008)

When I have asked WW2 Pilots about their preference when it came to Merlin v Radial the general opinion was that for pure power, lifting capacity, it was the Merlin, however, going into action they preferred the Radial which could have bits knocked off it and still get them home.
As mentioned very similar to the Spider Feathering Gear on a Paddler, this con rod set up is known as The Spider.
I have a Pot off a Bristol Hercules in the back garden. During the war production of these engines was done in a large underground facility near Bristol. My connection with the Bristol Aircraft Factory, loosely, was that I was travelling on a coach as a child which was shot up twice by a lone raider German Aircraft which was in the area, the noise of the incident live with me still along with screams. My Mother took us down to the village of Malmesbury in that area thinking it would be a safer place than Newcastle.
Louis, thinking about Radial engines in unusual places, the Americans had them fitted into some of their Tanks


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## OilJiver (Jun 30, 2014)

chadburn said:


> When I have asked WW2 Pilots about their preference when it came to Merlin v Radial the general opinion was that for pure power, lifting capacity, it was the Merlin, however, going into action they preferred the Radial which could have bits knocked off it and still get them home.


Knowing nothing at all about aero engines, I was amazed to find this to be true after a visit to Elvington Air Museum a while back. The radial engine just looks too femmer to me – but evidently not.


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## chadburn (Jun 2, 2008)

Thanks for your kind comments Louis, I have had an interest in fast craft for most of my life which included periods in the 1960's (when my seagoing career allowed) I was involved in the Offshore Powerboat scene. Met some great people like Don Aronow the designer of the very fast Cigarette boats and visited his factory in Miami, he was unfortunatley shot dead in his prime, the sport also attracted some rich villains like Emil Savundra (Insurance Fraudster who still owes me money). Many others but it would sound like name dropping(Jester). Roger Clark had a superb Ford Capri fitted with a V8.


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## skilly57 (Mar 11, 2008)

The other reason a radial engine would still perform after being shot up was the ethylene glycol coolant couldn't leak out the radial as it didn't need any! It was air cooled.

Many Merlins seized after being shot up simply because all the coolant was lost. The engine itself could be perfectly OK, but without any coolant it was time to hit the silk or crash-land the thing.

Skilly


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## chadburn (Jun 2, 2008)

Correct Skilly, it only took one bullet in the right place and the Merlin went from poweeeeeeeeeeeeer (reference to J.Clarkson) to useless.


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## Graham Wallace (May 6, 2006)

I am quite amazed that my personal guess was some sort of radial engine, I have never seen the internals before. Though I do not understand the rod at the 5 O'clock position.

Now I may not have seen one before but I usually hear one running every day. I live in Nanaimo and Harbour Air ( and others) run many single engine float planes to Vancouver, Victoria, Tswassen, Sunshine Coast North Vancouver Island and Westcoast/Port Albernie. The latter flight path is somewhat over my house. There are still many original Dehavilland Beavers Float planes) in operation using radial engines and their sound is so distinctive, wonderful to see and hear them chugging along.

There are also turbo prop and twin turbo prop Dehavilands but their sound is so different.

Graham


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## Farmer John (Feb 22, 2012)

I recognised it immediately, but then I do own a full service manual for the Viper and Venom radial engines. A surprisingly slim volume, you could do most of the work with about 10 tools.

Just been to look for it, it is not where I thought it was. Perhaps the Missus is reading it.


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## Peter Short (Apr 13, 2008)

Farmer John said:


> I do own a full service manual for the Viper and Venom radial engines.


Not sure you will find that book, Viper was a gas turbine, Venom an aircraft or motorcycle.... happy to learn something new though!


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## Farmer John (Feb 22, 2012)

Peter Short said:


> Not sure you will find that book, Viper was a gas turbine, Venom an aircraft or motorcycle.... happy to learn something new though!


Now I have to find it, I may have the names wrong but I do have the book. Anyone got a list of radial engines? I think it was a seven cylinder, then the second model was double-banked version of the first..


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## OliverD (Aug 30, 2011)

*Broken connecting rod--cause??*

As the aircraft crashed into water, do you suppose ingestion of a slug of water caused the engine to stop suddenly (hydro-locked) and this was the cause of the fracture of the connecting rod? 
I have seen a number of Detroit Diesel rods bent from excessive use of ether in cold weather, and have seen a bent rod in a small (1700) Ford tractor that tipped over into a pond. That engine even sheared the woodruff key that held the flywheel in position on a tapered crankshaft. 
Perhaps the construction and heat treatment of this part was such that it simply broke? Sudden stop--no flailing around to cause other damage?


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## Mad Landsman (Dec 1, 2005)

OliverD said:


> As the aircraft crashed into water, do you suppose ingestion of a slug of water caused the engine to stop suddenly (hydro-locked) and this was the cause of the fracture of the connecting rod?
> I have seen a number of Detroit Diesel rods bent from excessive use of ether in cold weather, and have seen a bent rod in a small (1700) Ford tractor that tipped over into a pond. That engine even sheared the woodruff key that held the flywheel in position on a tapered crankshaft.
> Perhaps the construction and heat treatment of this part was such that it simply broke? Sudden stop--no flailing around to cause other damage?


That thought occurred to me but I read the reports of the loss and it seems that the a/c went down at anchor during the nighr, therefore engines not running.
You are dead right on symptoms - I have seen the same myself as a result of hydraulic lock from vehicle entering ford without checking depth!


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## Ron Stringer (Mar 15, 2005)

Farmer John said:


> Now I have to find it, I may have the names wrong but I do have the book. Anyone got a list of radial engines? I think it was a seven cylinder, then the second model was double-banked version of the first..


Bristol's famous _Mercury _ 7-cylinder radial's cylinder dimensions were used in the _Hercules _14-cylinder sleeve valve radial. Both were very successful engines which were fitted into a wide range of military aircraft before and during WW2 and also into civil aircraft of the time.

That could also be said about Bristol's 9-cylinder _Pegasus _and the 18-cylinder _Centaurus_.


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## chadburn (Jun 2, 2008)

The problem with Radial Engines was that fuel would settle in the bottom cylinder(s) if the engine had not been in use and is the reason why they use to 'Walk the Prop'. On a Floating Flying Boat that could prove difficult, engine starting had to be done with care otherwise the engine would Hydraulic and damaged caused


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## Bill Morrison (May 25, 2013)

Hi to all on this thread. Many years ago I fell heir to a set of Newnes Aero Engineering, I never throw things like this away. There is a large reference to Bristol Radial engines. Have picked out three for this thread.
Bill


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## Farmer John (Feb 22, 2012)

Ron Stringer said:


> Bristol's famous _Mercury _ 7-cylinder radial's cylinder dimensions were used in the _Hercules _14-cylinder sleeve valve radial. Both were very successful engines which were fitted into a wide range of military aircraft before and during WW2 and also into civil aircraft of the time.
> 
> That could also be said about Bristol's 9-cylinder _Pegasus _and the 18-cylinder _Centaurus_.


Thanks Ron, but that is not the one. I will have to tear the house to bits, once daughters and offspring leave, they have just come to stay (delightful, but you do need a shed to hide in), I have a fair mark on the area of the house it will be in, but finding it is not easy. It was a very simple valve gear, like I said, 10 spanners and a ring compressor and valve spring compressor, and you could have it in bits on the kitchen table whilst the missus was redoping the wing fabric. 10 spanners is a massive over-estimate. Four.


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## malivoij (Jun 4, 2008)

*JohnM*



bones140 said:


> This part has a VERY tenuous link to the world of boats. No more clues. The more eagle eyed among you may notice a defect!


Appears to be connecting rod/crank assembly 9 cylinder radial engine with 1 connecting rod broken at piston end.
Typical of radial aircraft engine


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## cubpilot (Aug 18, 2008)

I am in the process of getting a 9 cyl radial installed on a Stinson Gullwing aircraft. The engine most commonly used for the Gullwing is a Lycoming 680r.
Nominally 300hp they have a great sound in flight.
Plenty of other radials still in use in General Aviation and a reasonable stock of spares for the popular models.
Normal practice when leaving the engine unused for a day or longer is to remove bottom cylinder spark plugs and hang tin cans to collect oil that seeps from crankcase past piston rings. Very important to pull engine through by hand to prevent hydraulic lock before starting.


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