1930s Fiat V24 Aero Engine

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BenL

This weekend, a museum fired up a newly restored Fiat V24 aero engine for the first time.

warbirdsnews.com

"Awakening of the Myth" - Fiat AS.6 Engine of Macchi-Castoldi Fame Roars to Life!

warbirdsnews.com warbirdsnews.com

"This massive, V-24 engine powered the legendary Macchi Castoldi M.C.72 seaplane on its world absolute speed record flight (440.681 mph) of October 23, 1934"

The end of the article has a link to the video. The first part of the video shows them starting the engine at night. It has no exhaust headers so you can see the flames emerging from the cylinders. (the second part of the video in the daytime is less exciting)
 
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Brian

Interesting if not maybe slightly misleading. If the 2 props are driven by 2 separate sets of 12 cylinders, I can't allow it to be called a V24. Perhaps 2 conjoined V12s.

Not sure how they did it. I guess there's a jack shaft taking power from the rear to a gear in the prop spindle. If the cranks really were concentric, imagine how big the rod journals would have to be.

Thanks
 
MikeP

Mike Pass

Supporter
Macchi MC72 pic
Cheers
Mike
1698249497621.png
 
manta22

Neil

Supporter
Scott Calabro said:
Several engine manufacturers built engines using similar design architecture during this era of aviation. Daimler Benz comes to mind.
You guys would enjoy a book titled “ The Secret Horsepower Race”


It really is one engine, I just had two crankshafts!
Click to expand...
Taking the drive from the center of the V-24 crankshaft increases its torsional stiffness but I have to wonder why they didn't just increase the V-12 bore & stroke
 
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colin artus

I would think that the use of the 24 cylinder layout rather than a larger V12 was a matter of cda; retaining as small a frontal area as possible, which is quite important at 400 mph + speeds.
 
Ron Earp

Ron Earp

Admin
I didn't know about this engine. Reckon it might have needed that shaft running down the vee since they can get a reduction out of it. Lots of aircraft engines need to get the crank speed down to a friendly prop speed, but I don't know if this engine needed that or not. Maybe if only turned to 2400 to 3000 RPM or so it'd be okay to drive drive.
 
weisserheilbronn

Markus

SPRF40
Lifetime Supporter
colin artus said:
I would think that the use of the 24 cylinder layout rather than a larger V12 was a matter of cda; retaining as small a frontal area as possible, which is quite important at 400 mph + speeds.
Click to expand...

The guy in the video below (around 2:50) mentions something about the counter rotating propeller makes the plane fly in a straight line......?!

 
manta22

Neil

Supporter
colin artus said:
I would think that the use of the 24 cylinder layout rather than a larger V12 was a matter of cda; retaining as small a frontal area as possible, which is quite important at 400 mph + speeds.
Click to expand...
Yes, going to a larger displacement V-12 would cost a bit in frontal area but the gains in simplicity, reliability, and lower weight should offset that.
 
Scott Calabro

Scott Calabro

manta22 said:
Yes, going to a larger displacement V-12 would cost a bit in frontal area but the gains in simplicity, reliability, and lower weight should offset that.
Click to expand...
Except that then when you would have to dictate that lead (dead weight) would have to be added to compensate for the forward CG of a higher displacement engine, it becomes a diminishing return.
Higher power density aircraft engines of later designs negate these problems.
 
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