Can You Add To These?

[siznaudin]

In the process of identifying a 9 cylinder radial in a french museum I've (finally) twigged that most single row radials have the pushrods located at the front. The engine in question, a Wright/Continental R-975 has them at the rear, which is how I was at last able to nail it. Further surfing/research has turned up only one other so far: the Kinner.

 

Couple of questions come to mind ... are there any others out there, and also, I wonder if anyone from Kinner was looking over Wright's shoulder or vice versa. Or was there some commercial interplay 'twixt Wright & Kinner./

 

Or this .. why have 'em at the rear anyway? Surely there must have been some rationale involved...:confused:

 

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[willedoo]

Not sure if there's any connection between the two. The Kinner and R-975 have a totally different cam system. It might be coincidence that they both have rear facing pushrods.

 

The Kinner has some commonality with the M-11 Shevtsov (Po-2, Yak-6, Mig-8 etc.), in that they both have individual camshafts for each cylinder instead of the usual central common cam ring as in the R-975. The Shevtsov has the pushrods at the front though, unlike the Kinner.

 

Shevtsov M-11

 

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Cutaway of a Continental R-975 tank engine. You can just see the cam ring in front of the cam gear.

 

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But none of this explains the reason why the two engines have the pushrods at the rear of the cylinders.

 

Cheers, Willie.

 

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[siznaudin]

I've done a bit more reading and see that Continental's A-70 of 1928 - 7 cylinder 544cubic inches - had rear located cam & pushrods. Herschel Smith doesn't suggest a reason for this, however.

 

And two others - the Velie M5 of the same year - 251 cubic inches, plus the LeBlond series.

 

Radial engine cam rings are "doubled" in that the exhaust lobes and inlet lobes are carried on the one rotating ring.

 

Not sure what is going on at the pushrod/cam follower region on the Shvetsov pictured but I can only imagine that it still has a doubled cam ring like the others.

 

Could you explain somehow the "individual camshafts" reference with respect to the Shvetsov?

 

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[siznaudin]

Chased up the Kinner cam stuff and lo & behold here we are: it reminds me a bit of the myriad of spur gears hidden within the casing of the sleeve valve Bristol engines, but on a thankfully lesser scale.

 

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[willedoo]

Haven't seen a drawing of the Shvetsov cams, but from what I can gather, they are very similar to the Kinner's individual cams for each cylinder.

 

I wonder whether the rear pushrods were just an experiment, or designed for a specific purpose. There would be only two factors at play, I'd guess: the gear train or porting. The R-975 has the cam gear running off the rear drive train, but it's just as easy to have the cam drive and ring driving off the front of the crank like other radials. The conventional setup makes more sense - cams, tappets, pushrods at the front; valves at the back for more direct porting to the supercharger and exhaust. I'll see if I can find a cylinder head diagram of the R-975.

 

I'd imagine the Continental tank engine would be basically the same as the aero engine, apart from cooling fan, shrouds and accessories.

 

Cheers, Willie.

 

 

[willedoo]

I should have taken more notice of the original photo posted above of the R-975. The rocker boxes have quite a pronounced cantilever rearward to accommodate the rocker arm and pushrods. This would put the valves and ports in much the same position as the more common engines, so no real disadvantage or advantage there.

 

Maybe they thought there was some gain by having the cam gear running off the rear with the other drives.

 

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I think I'll quit while I'm ahead and wait for a mechanic's opinion.

 

Cheers, Willie.

 

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[mnewbery]

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Lanape Papoose as used on some Piper cubs

 

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[siznaudin]

[ATTACH=full]1558[/ATTACH]Lanape Papoose as used on some Piper cubs

Well, that's a new name for me ... well done!

I had a reply regarding why some of the radials around the late 20's had rear mounted pushrods/cam plates.

 

It was just a guess that it might have made for more space for the prop reduction gearing at the front.

 

We probably will never know for sure why it was done. Different matter altogether for a two row radial, of course.

 

Here's one which might tickle the grey matter ...

 

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[mnewbery]

Here's one which might tickle the grey matter ...

Augh! My eyes!

http://thekneeslider.com/honda-xr600-9-cylinder-radial-engine-update/

 

Wonder why no-one else did it?

 

Cam drive consist of 12 gears in three planes in the front section of crank case.

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Now for some ol' skool. This is the Anzani Military model fan type engine as used on the Bleriot XI - one exhaust valve aka "mono soupape" with air entering at the bottom of the barrel. 55 and 72 degree angles were produced with a range of 3 to 3.53 litres. Of course the fuel would contain castor oil and that oil (a natural laxative) would soak the pilot. You'd get more power out of a modern scooter. We are talking about post WWI technology though. This engine style was also used in some motorcycles.

 

Keeps the "regular" in RPT

 

http://en.wikipedia.org/wiki/Anzani_3-cylinder_fan_engines

 

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[mnewbery]

Curtiss Chieftan ... yes they did have rear cylinder cooling issues at high power low speed settings. Curtiss bleeted un-endingly about how this engine could compete with liquid cooled engines on their own terms (for a few minutes at least). Note the bevel gear overhead camshaft drive - more common on the Kawasaki W650 and Ducati 860SD/900SS motorcycles.

 

http://www.pilotfriend.com/aero_engines/aero_chieftain.htm

 

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11 Cylinder (count e'm) Clerget radial model 11EB. This model produced 200hp in competition with the Gnome et Le Rhone model. Clerget used two valve heads and a carburettor in comparison to a single valve and selecting power by shorting some of the spark plugs. Bentley ripped off improved the design between 1916 and 1920 with the BR1 and BR2, up to 245 Hp. Clerget-Blin eventually got absorbed into what is now SNECMA.

 

http://en.wikipedia.org/wiki/Clerget_aircraft_engines

 

http://www.powerhousemuseum.com/collection/database/?irn=213282&search=clerget&images=&c=&s=

 

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[willedoo]

Here's one which might tickle the grey matter ...

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I'm getting a headache trying to figure out what that looks like inside the crankcase. As far as the firing order goes, I'll try not to think about it.

 

Cheers, Willie.

 

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[mnewbery]

Here's one which might tickle the grey matter ...

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THE BAKEWELL WINGFOOT AERO ENGINE: 1939 Courtesy of:

 

http://www.douglas-self.com/MUSEUM/POWER/unusualICeng/miscIC/miscIC.htm#ba

 

This is in fact four v-twin engines in a common case. In 1909 four v-four engines was already "done by Breton. Bakewell and Breton are both English towns.

 

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[siznaudin]

Save my time serarching for "Breton" and tell me more, please... I like it!

 

Here's my all-time favourite for complexity and why did they bother, when turbines were already there.... here, the pistons slogging away in their barrels were only really (if extrapolated to the ultimate) serving to act as hot air producers for the turbine, since it was coupled to the propellor.

 

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[mnewbery]

The engine combines

 

• fixed port timing rather than valves; (ironic)
   
   
  
• diesel compression for efficiency and a wider range of fuels;
   
   
  
• a propellor for STOL, a wastegate for high altitude; and
   
   
  
• exhaust scavenging (like all turbo chargers) plus cabin pressurisation ability.
   
   
  

 

 

Finally a lot of the technology was common to the automotive engines of the era, such as the Commer "Knocker" TS3. Therefore the skills required for at least some of the maintenance would be easily accessible. Jets were still a bit of black magic at the time of the napier nomad (pictured above) as used experimentally in the AVRO Lincoln (200 KTAS at FL200 cruise / 300KTAS at FL180 max).

 

http://en.wikipedia.org/wiki/Napier_Nomad

 

The nomad mark 2 had the lowest SFC of any aero engine up to that point but it weighed ~1700Kgs with oil. At 89 PSI inlet pressure it was churning out 3150 HP, comparable to the radials of the time (see below). The original nomad did used afterburning to produce some of the thrust. The Nomad 2 deleted this and some of the other components.

 

Two strokes suffer from a lack of breathing (spirometric) efficiency, hence the need for supercharging. The Wright 3350-93W Turbo compound radial was a four stroke version of the same idea producing ~3500Hp with high octane avgas. You can't buy that avgas anymore but the nomad engine will run on avgas petrol plus diesel, palm or coconut oil. Also, the little impeller on the side which looks a bit like a water pump was a gear driven supercharger used for starting and high power boost. Otherwise it was disconnected for cruise flight.

 

Compare:

 

http://en.wikipedia.org/wiki/Wright_R-3350_Duplex-Cyclone

 

 

[siznaudin]

... the Anzani Military model fan type engine as used on the Bleriot XI - one exhaust valve aka "mono soupape" with air entering at the bottom of the barrel. 55 and 72 degree angles were produced with a range of 3 to 3.53 litres. Of course the fuel would contain castor oil and that oil (a natural laxative) would soak the pilot. You'd get more power out of a modern scooter. We are talking about post WWI technology though. This engine style was also used in some motorcycles.[/quote]I'm unclear as to the induction/carburetion arrangement on the Anzani engine pictured. My impression is that the drilled holes at the base of the barrels were mainly to allow supplementary exhaust gas evacuation. I'll attach an Anzani "six" ... ie a two row "three" which shows what I suspect cannot be seen in the motor in your post - ie a second valve spring/valve; presumably(?) for induction.

As well, I associate "monosoupape" not with Anzani, but with Gnome engines above all others - particularly with the Gnomes that followed after they had done away with the inlet valve-in-piston crown. Looking forward to your expansion on these matters.

 

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[siznaudin]

...Jets were still a bit of black magic at the time of the napier nomad (pictured above) as used experimentally in the AVRO Lincoln (200 KTAS at FL200 cruise / 300KTAS at FL180 max).I appreciate that it was indeed early days for jet engines, but also point out that the Armstrong Siddeley Sapphire & J65 were contemporary with the Nomad.:)

My main point is that the Nomad was one hell of a complicated way to go about what could be ... and has been, achieved using jet engine (non reciprocating) technology - involving so many mechanical "lumps" hurtling back and forth within cylinders. Glorified steam engines, really...;)

[mnewbery]

I'm probably wrong about the holes in the W engine. When the museum opens in January I'll pull some strings and go have a look. The viewer might wonder if the holes appear on both sides of the cylinder and how the pilot felt about that, being covered in crud after a few minutes. Further the Gnome et Le-Rhone company a) wasn't the only company to use a single exhaust valve and an atmospherically actuated flap b) monosoupappe just translates to "single valve" from French.

 

I'd stick to aero engines in this discussion. Gramps owned some motor cycle racing teams between the world wars so I have many references for Jawa, BSA, Triumph, NSU-DKW, Harley Davidson, Piaggio and Velocette.

 

It wouldn't be fair to compare a Harley IOE engine from 1911 with a Gnome for example. Both used atmosphere to actuate the inlet valve.

 

 

[willedoo]

The Wiki page on the Anzani engine doesn't shed much light on the induction system:

 

"They were all air-cooled side-valve engines; each exhaust valve was controlled from below by a cam in the crankcase.[2] Each was mounted in a cell to the side of the cylinder, with the automatic, atmospheric pressure -driven spring-loaded inlet valve immediately above it, partly to minimise volume and partly to help cool the hot exhaust valve."

 

This article about an Anzani restoration mentions the ports at the bottom of the cylinders.

 

http://stcroix.50webs.com/pages/anzani_story.html

 

Must be a bit more detail somewhere around the place.

 

Cheers Willie.

 

 

[willedoo]

Getting a bit off track here, but at least it's on the subject of radials.

 

Here's a clip of a Goggomobil fitted with a Russian Vedeneyev M14P nine cylinder radial; not quite as elegant as the Monaco-Trossi, though.

 

Sounds a bit better in part 2 of the video.

 

 

Cheers, Willie.

 

 

[siznaudin]

The Wiki page on the Anzani engine doesn't shed much light on the induction system:"They were all air-cooled side-valve engines; each exhaust valve was controlled from below by a cam in the crankcase.[2] Each was mounted in a cell to the side of the cylinder, with the automatic, atmospheric pressure -driven spring-loaded inlet valve immediately above it, partly to minimise volume and partly to help cool the hot exhaust valve."

 

This article about an Anzani restoration mentions the ports at the bottom of the cylinders.

 

http://stcroix.50webs.com/pages/anzani_story.html

 

Must be a bit more detail somewhere around the place.

 

Cheers Willie.

That's a classic description of what, in the veteran car movement anyway, is referred to as "the De Dion type" engine. Our Sizaire has such a valve configuration although (thankfully) the inlet valve is cam operated rather than the oh-so asthmatic spring loaded flapper type "atmospheric" variety.

The Anzanis I believe came in that configuration in their early days, and it looks to me as though they came later both with and without the drill holes around the bottom of the barrel. Early racing motorcycles employed such drill holes in the quest for more performance. One wonders, however, whether the increased noise level merely produced the impression of more power. Something similar still seems to occur today, as witness the drain pipe sized exhausts fitted to so many road registered cars.

 

Thank you Newbs for translating "monosoupape"- most illuminating. As I said, it is a term which was primarily associated with Gnome at the time they gave up on the valve-in-crown arrangement, and in no way was I intending to suggest they were the only single valved engine. Or were they, I wonder...?:confused:

 

 

[siznaudin]

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Newbs... I'm more than somewhat confused: are you certain that the thing that looks like a water pump is in fact not a water pump?

 

If not, where is the water pump to be found?

 

 

[mnewbery]

If you can find a supercharger, then it's a water pump on each side. Sorry. I looked really really hard for the water pumps. I think there are two water pumps - above the engine between the 2nd and third last cylinder bank and again directly above the front cylinder bank.

 

There is a gear type (roots) pump directly under the prop shaft. That could be for anything.

 

The Napier sabre had its super charger in line with the crank shaft which was quite obvious.

 

 

[siznaudin]

I managed to dig this one out of my hard drive ... makes more sense now. Happy New Year to all.

 

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