gardner 2lw Gardner 2LW Crankshaft crank pins - offset? Not 180 degrees.

[Tacet]

On 05/05/2022 at 10:47, MtB said:

 

Also different for a four stroke twin cylinder with crank pins aligned, e.g. a Kingfisher KD2.

 

And what about Harleys, V twins.....?!! 

 

On 05/05/2022 at 10:49, TheCoot said:

A V-twin must be very different to an in-line twin.  Sharing a crank pin for example.

V twins have a common crankpin usually (but not invariably) - so the firing is out by + or - the V angle.  Mostly, the big-ends are offset on the crankpin - but sometimes forked conrods are used.

 

Perfect primary balance can be achieved with an angle of 90 degrees or more, which is surprising at first glance. 

[john.k]

V twins generally do have the same crankpin for both cylinders..........an unusual example of a different scheme was the Howard V twin used on the well known Howard tiller,or rotary hoe......these used a weird triple flywheel setup ,apparently to get an equal firing interval ..........which may have had something to do with the magneto used.

[Bee]

Fascinating - really, not being sarcastic - stood in front of a cutaway radial engine from an aircraft a while ago thinking sod that for a lark, if that ever went wrong somebody else would have to fix it, I wouldn't lay a spanner on it.

[MtB]

9 minutes ago, Bee said:

Fascinating - really, not being sarcastic - stood in front of a cutaway radial engine from an aircraft a while ago thinking sod that for a lark, if that ever went wrong somebody else would have to fix it, I wouldn't lay a spanner on it.

 

Ah yes, is that where the crankshaft remains stationary and six or eight pistons rotate as a ring joined directly to the propeller?

 

Elegant lateral thinking from before De Bono gave it a name!

[BEngo]

22 minutes ago, MtB said:

 

Ah yes, is that where the crankshaft remains stationary and six or eight pistons rotate as a ring joined directly to the propeller?

 

Elegant lateral thinking from before De Bono gave it a name!

No.  The type of engine where the pots go  round and the crank stays still is called a rotary engine.  Banned as unairworthy for new aircraft soon after WW1.

 

A radial engine has rows of radially disposed fixed cylinders and a rotating, usually single throw crank.  There is one master rod which rotates on the crank and all the other rods are articulated to the master rod.  Have a look at Bristol Centaurus for detail.  This is also a sleeve valve, just to make things more complex.

[Tracy D'arth]

33 minutes ago, Bee said:

Fascinating - really, not being sarcastic - stood in front of a cutaway radial engine from an aircraft a while ago thinking sod that for a lark, if that ever went wrong somebody else would have to fix it, I wouldn't lay a spanner on it.

A clockwise or anticlockwise one?  That's the really clever part.

[IanD]

On 07/05/2022 at 09:27, BEngo said:

No.  The type of engine where the pots go  round and the crank stays still is called a rotary engine.  Banned as unairworthy for new aircraft soon after WW1.

 

A radial engine has rows of radially disposed fixed cylinders and a rotating, usually single throw crank.  There is one master rod which rotates on the crank and all the other rods are articulated to the master rod.  Have a look at Bristol Centaurus for detail.  This is also a sleeve valve, just to make things more complex.

Single throw crank? Not after things got a bit out of hand... 😉

 

https://www.macsmotorcitygarage.com/lycomings-leviathan-xr-7755-the-largest-u-s-aircraft-engine-of-world-war-ii/

 

I saw this at the Smithsonian, and it's ginormous...

Edited May 9, 2022 by IanD

[springy]

On 07/05/2022 at 09:27, BEngo said:

No.  The type of engine where the pots go  round and the crank stays still is called a rotary engine.  Banned as unairworthy for new aircraft soon after WW1.<snip>

IIRC the gyroscopic effects of the rotating mass of the barrels and pistons meant that if you had to turn just after take off and "chose" the wrong direction it could bring you back down to earth sideways.

 

springy

[IanD]

33 minutes ago, springy said:

IIRC the gyroscopic effects of the rotating mass of the barrels and pistons meant that if you had to turn just after take off and "chose" the wrong direction it could bring you back down to earth sideways.

 

springy

It did mean a Sopwith Camel could turn really fast in one direction though so Biggles could shoot down the nasty Hun... 😉

[BEngo]

12 minutes ago, IanD said:

It did mean a Sopwith Camel could turn really fast in one direction though so Biggles could shoot down the nasty Hun... 😉

But only to the right, and only if he was ready for the associated sharp drop of the nose.

 

The other draw back was the need to mix Castor oil with the fuel, at about a pint in a gallon of fuel, so pilots were inhaling Castor oil, with the associated consequences.  BlackBerry brandy was apparently the cement of choice in the RFC.  I presume the RNAS pilots stuck to rum.

 

N

 

[IanD]

11 minutes ago, BEngo said:

But only to the right, and only if he was ready for the associated sharp drop of the nose.

 

The other draw back was the need to mix Castor oil with the fuel, at about a pint in a gallon of fuel, so pilots were inhaling Castor oil, with the associated consequences.  BlackBerry brandy was apparently the cement of choice in the RFC.  I presume the RNAS pilots stuck to rum.

 

N

 

 

I always wondered what that company did before mobile phones with an alphanumeric keyboard became popular... 😉

[BEngo]

Bloody spillchuckers.

N