Jump to content

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


TheCoot
 Share

Featured Posts

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. 

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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!

Link to comment
Share on other sites

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.

  • Greenie 1
Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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 by IanD
Link to comment
Share on other sites

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

Link to comment
Share on other sites

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... 😉

Link to comment
Share on other sites

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

 

Link to comment
Share on other sites

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... 😉

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.