Historic Aircraft: Sopwith Camel & Spitfire

[75Plus]

This historic video was shot in New Zealand. Listen to that
Spitfire's Merlin engine after the Sopwith has landed. The two
 historic fighters were flown side by side to showcase the advance
 in technology in only 20 years! The Sopwith Camel and the
 Supermarine Spitfire are icons of their respective eras, both
 efficient designs that were very effective. The Sopwith Camel was
 first flown in 1916. The Supermarine Spitfire made its maiden
 flight Mar. 6, '36.

Click the link.

**Embedded the link for you...   Eric

[rudydubya]

Very interesting and enjoyable.  Thanks for sharing.

Regards,
Rudy

[AdeV]

That particular Camel sounds a bit unhealthy; here's a link to one that appears to be running properly (shame about the amateurish commentary):

[Brass_Machine]

I love the sound of old planes.We had a B52 doing some fly overs a few months back. Unfortunately I did not have the digital video with me.

I embedded the video for you.

Eric

[mattinker]

That particular Camel sounds a bit unhealthy;

The first on sounds unhealthy I would think for a few reasons. It was a cold engine running at ground level. As the engine is radial with the block turning the carburation was a real problem as this had to be done through the centre. The engine speed being controlled partly using ignition cut out explains why it sounds lumpy when cold and not flat out. I don't know whether the Sopwith Camel was set up top run at a specific altitude, some early aero engines were very lumpy cold on the ground because of this.  In the second video, we don't see the engine running cold.

This is old information that I can't be more precise about, but it was at a time when aero engines were really in their infancy! Maybe someone else give more details?

Regards, Matthew

[Raggle]

See how far the Spitfire's manufacturers had come in just 11 years from the Camel.

http://en.wikipedia.org/wiki/Supermarine_S.5

I've got a year of magazines somewhere from 1927 with an article on that Schneider Trophy Race, I'll have a search.

Ray

[Fergus OMore]

So we are getting near to my bit. I was at RAF Hendon in 1949 when there were two squadrons of Spitfires belonging to 601 and 604 Squadrons, plus three 'adopted' Spitfires.
One was TB-713, a LFIX , another was a 14 PM-959 and used by Air Vice Marshal Boothman of Schneider Trophy fame and the other was the famous SL-721 whose driver was 'Jimmy Robb' Boss of Fighter Command. JM-R is still airworthy and in Canada now.

601's 'boss was Hon Max Aitken who was another air ace and son of Lord Beaverbrook, who was Minister of Aircraft Production during the War.

Squadron leader Arthur Fane De Salis( later Wing Commander and then Group Captain was boss man of RAF 31 Squadron- which still exists today -flying Tornados out of Marham.

I've just posted off my greetings cards to the last two survivors of my days with 31.

But we have to move on. The story is of progress in aviation and in 1949, I went to Farnborough to see the Brabazon fly over- ex Filton, the Comet 1 flown by 'cats eyes ' Cunningham of the Pathfinders, the Shackleton still in use today, and the 'fighter'or so the Yanks thought - Canberra 1 bomber. It was all rather fun because we had pretty little Percival Proctors- from Jean Batten days flying solo  to Oz and New Zealand in a Vega Gull and that sweetheart, the Avro Anson.

It was all rather boring. I was in a jet and  coming home with my missus in October and suddenly thought, this thing was going far faster than a Spitfire-in a dive.

Probably the next thing is 1915 when our little squadron will be 100 years old. I wonder whether I will be there to see it.

[AdeV]

That particular Camel sounds a bit unhealthy;

The first on sounds unhealthy I would think for a few reasons. It was a cold engine running at ground level. As the engine is radial with the block turning the carburation was a real problem as this had to be done through the centre. The engine speed being controlled partly using ignition cut out explains why it sounds lumpy when cold and not flat out.

I would agree with all that; the other issue of course was when stationary, the oil tended to train into the lowest cylinders, so fouling the plugs...

However, even well into the flight with the Spit, the Camel engine is clearly revving, missing, revving, missing, and is producing a lot of smoke (oil or fuel, I can't really tell). Yes, I did note it was a total loss lube system & therefore smoke would generally be expected, but not in "puffs" I suspect.

[Fergus OMore]

I think the problem was the use of castor oil in what was a total loss system in these old aircraft engines.

Enough to give pilots a doze of the -----------------------------------------and it did.

For those who perhaps missed their organic chemistry lesson that day, the esterification of fatty acids does create varnish- and worse.

And a Merry Xmas to All our Readers.

[mattinker]

[/quote]

I would agree with all that; the other issue of course was when stationary, the oil tended to train into the lowest cylinders, so fouling the plugs....
[/quote]

AdeV,

There is no lower cylinder on a Sopwith Camel the cylinders turn and the crankshaft is fixed. I would guess at accumulation of oil in a cylinder through a fouled plug, clearing and firing. From what I could gather, the oil mixed with the air/fuel mixture in the crank-case, (hence the reason for caster oil that was not diluted) so the only place for it to go once it had gone through the oil ways was through the cylinder heads and out of the exhaust!

http://www.canadianflight.org/content/the-sopwith-camel the explanation of the lubrication system and the induction set up is not very complete!

For those that read "Biggles" when young, "the Sopwith Camel ticking over like a well oiled sewing machine" is pure fiction!

Regards, Matthew

[AdeV]

Matthew - what I mean is, when the engine is not running, the (leftover) oil tends to drain to the bottom of it; which can cause plug fouling.

Yes, when the engine is running, there is no such thing as "the bottom cylinder".

[Pete W.]

Hi there, all,

I don't understand why rotary engines rotate!    

Please can someone explain to me why it's advantageous for aero-engines to rotate the cylinder assembly rather than the crankshaft?  Is it to do with weight or smoother torque or simplified valve-gear or what?

Please be patient and gentle with my ignorance - I'm not well-versed in infernal combustion engine technology!    

Best regards,

Pete W.

[Pete.]

Only advantage I can think of is that the pistons and rods are not reciprocating as they do with a spinning crank. Might not have been easy to make a lightweight engine with strong enough conrods back then.

[BillTodd]

Please can someone explain to me why it's advantageous for aero-engines to rotate the cylinder assembly rather than the crankshaft?  Is it to do with weight or smoother torque or simplified valve-gear or what?

Yes essentially. 


With old, low power, engines  aircraft and their power units had to be as light as possible so there was a great advantage in using the weight of the whole cylinder block as a flywheel (instead of having an additional flywheel - the wooden prop being to light to act as a flywheel alone . Spinning the cylinders also helped to cool the engine (low efficiency means lots of heat )  The radial engine layout has a great advantage of being short and having all it's cylinders well exposed for air cooling.

However, as the engines became more powerful and heavier, the spinning engine's gyroscopic effect started to become a problem for the airframe. Designers looked for alternatives - One solution the reaction-less engine, was to spin the engine one way and the prop the other  coupling the torque to the airframe with a differential gear!


Bill

[andyf]

I know less than nothing about radial engines, but could it be that the rotating mass of the cylinder block (or perhaps I should say cylinder ring) meant that no heavy flywheel was needed?

Andy

PS Pete, I think the rotary engines under discussion have reciprocating pistons and conrods; see http://en.wikipedia.org/wiki/Rotary_engine. Were you perhaps thinking of the Wankel rotary engines ( http://en.wikipedia.org/wiki/Wankel_engine ) fitted to some Mazda cars from the late '60s onwards?

[John Hill]

I think the commentary of the Auckland flight explained why the engine sounded the way it did and I rather suspect the aircraft in the second film had been fitted with a more modern engine.

The original engine had no throttle and power was adjusted by cutting cylinders in and out via magneto switches, hence the sound.

[Pete.]

PS Pete, I think the rotary engines under discussion have reciprocating pistons and conrods; see http://en.wikipedia.org/wiki/Rotary_engine. Were you perhaps thinking of the Wankel rotary engines ( http://en.wikipedia.org/wiki/Wankel_engine ) fitted to some Mazda cars from the late '60s onwards?

What I see is they have the effect of a reciprocating piston but the rods and pistons merely rotate around a fixed point (the crank pin).

[75Plus]

Here is a video of a 1918 Gnome engine running on a test stand.

[ Invalid YouTube link ]

Joe

[DavidA]

Norman,

...For those who perhaps missed their organic chemistry lesson that day, the esterification of fatty acids does create varnish- and worse...

Indeed.  It also produces very good bio-Diesel.  My car loves it.

Dave.

[Pete W.]

Hi there, all,

Thank you for your replies to my question.

Andyf:  no, I wasn't referring to the Wankel engine.

BillTodd:  I can see that using the cylinder ring in lieu of a flywheel would make sense.  I also appreciate your point about the gyroscopic effect - I believe one of the Land speed record attempts failed because the gyroscopic torque from the rapidly rotating wheels rolled the car when the driver tried to steer.

Now some more questions:

Were rotary aero-engines two-stroke or four-stroke?

How was the fuel fed to the cylinders?  I can't see that crank-case induction would work, surely the displacement of all the pistons would cancel out?

Best regards,

Pete W.

[AdeV]

Pete,

This link might help: http://www.animatedengines.com/gnome.html

The bit I can't work out is, what opens the exhaust valve? I presume there's a cam/pushrod/rocker somewhere.

[BillTodd]

Were rotary aero-engines two-stroke or four-stroke?

Four stroke

The only rotary two stroke I can think of, is Cecil Hughes' is superbly designed  double-ended curved cylinder  engine (you really have to read the patent to appreciate the engineering).  It used an external blower for the scavenging air.



http://www.douglas-self.com/MUSEUM/POWER/unusualICeng/rotblocIC/rotblocIC.htm#selwood

How was the fuel fed to the cylinders?  I can't see that crank-case induction would work, surely the displacement of all the pistons would cancel out?

In the case of the Gnome (above) it was from the crank case,  through a valve in the piston (operated by cylinder vacuum during the induction stroke - I'm not sure how they balanced the centrifugal force on the valve). 

Other engines had external pipe work to the rear of the engine where a toroidal chamber around the crank distributed the mixture to the all the cylinders. The carb fed the chamber either,  via another annular chamber with a rotating seal to the toriodal one, or via a hollow crank shaft.