Strange truck quiz

The Winner.

Although made for the Sherman tank this effort by Chrysler (and it was quite successful in mass production) has to be the ultimate in multi-engine vehicle technology. Amazing what you can do with 5 old flat head 6 cylinder engines.

Click on here for the story:
autospeed.com/cms/title_The-Chrysler-A57..._112613/article.html

...thanks for the heads up ivor .. wonder what happened to the 'sixties jigger?....

...a bit off topic but the ultimate winner (albeit in an aeroplane) were the massive ''corn cobs''....giant Pratt and Whitney 36 cylinder air cooled monsters that powered the last of the piston engined airliners...4 rows of 9 cylinders with 4 of these per 'plane, with an amazing array of cold air ducting, spark plugs, magneto's and incredible complexity for safely travelling great distances, and over oceans for hours and hours on end....

...there may have been even bigger aero engines for the military (of any sovereign denomination) and the ingenuity of these engine and aeroplane builders were peerless in their day .....cheers

Detective

You are certainly right about the corncob engines being complex but when you have that many cylinders you can afford to have a couple of hitch-hikers and not notice it in the cruise. How do you find which ones are bad?

Pilot fault report: One or two missing cylinders.
Engineer action report: After short search all cylinders found.

Still, it is a single engine. As far as multi engines go I think Chrysler takes the cake with 5 almost totally independent engines with just their oil pans removed.

Lang

g'day Lang .. i believe (idstbc) that the engine had it's genesis in the 9 cylinder radial...and she just grew from there .....hence the 4 rows.....

...engineer to captain ''captain..we gotta leak in one of the engines''

....captain to engineer ''permission granted'' !!

The last of the piston engine days- back in 1965 I went to a school which was under the Adelaide flight path, and I clearly remember the TAA liners coming in with several motors windmilling often enough for it to be normal (even at age 9 I was thinking what the..) More recently I saw a doco on telly where it was revealed that as the motors were being tuned up for more power it was not uncommon for a motor to have a very short life and for engine changes to be a regular occurence. Coming to Sydney we flew on a then new (to Australia) 727.

Steve,

I think you will find that doco was a a bit of scuttlebut. Aircraft engines are never "tuned up" except maybe air racing engines. If you want to change the colour of the plug leads it needs an engineering drawing. They are what they are and always rebuilt to standard parameters.

The old DC-6 engines, which you were probably looking at, were very reliable but they had their moments from time to time. Shutdowns in the air would have been very few and far between. You could well have been looking at currency pilot training which involves deliberately simulating shutting down an engine for practice. In this case the props would have been "windmilling" with zero thrust power set. If the engines had really been shut down the props would have been feathered and stopped completely.

By going to Sydney in a 727 and not a DC-6 you went from an aircraft with 1,200 hours between complete engine overhaul to one with maybe 30,000 hours. Life is sure easier (and safer) now.

Lang

g'day mammoth .. in deference to Lang, a windmilling propellor is a pilots' worst nightmare...especially in the big airplanes...

...essentially the engine is ''off'' but the prop and its associated mechanisms don't know this, which then leads to a catastrophic failure of all the prop gear due to oil starvation...which then means an unchecked propellor will simply shear off due to seizure of its working shafts and parts...

...when that situation occurs there is usually no hope for the ship, as that great big whirling mass just tears a path of destruction through everything....including that which is either side of its original location

We are getting off the thread a bit but, not to enter a pissing competition with Detective, a windmilling prop danger is not from engine damage. It is from drag.

All the auxilliaries such as oil pumps, generators etc don't know whether they are being driven by the pistons or prop and continue to work normally. It is very hard to tell at a panicked glance if a windmilling engine has stopped operating just from the instruments. Lots of aircraft have crashed from the pilot shutting down the good engine!

The drag from a windmilling prop is huge - basically a fan being driven by an airflow giving lift in the opposite direction ie reverse thrust. You can see this on the mighty power produced by an electricity wind farm propellor or on a sailing boat which has the engine stopped and prop shaft in neutral just spinning - by locking it there could be a 10% increase in boat speed.

Many an aircraft has been lost by the pilot being too slow on an engine failure on take-off to feather the prop(turn the blades so the sharp edge is towards the airflow). Few loaded twin engine aircraft can maintain height with a windmilling prop - the good engine merely takes you directly to the scene of the accident.

Even if something has happened to the feathering system you need to slow the aircraft down to stop the turning and keep it below a speed where the airflow starts to drive the engine. A stopped unfeathered prop, although not good, only has a fraction of the drag of when it is turning.

Lang

...thanks Lang for the clarification .. was mostly thinking of a runaway windmilling propellor...just i forgot to mention that bit :-[ :-[