FIAT A.S.8 ENGINE. - Aircraft of World War II

jerryw · 08-22-2008, 11:29 PM

The Fiat A.S.8 engine was designed and developed in Italy during the early years of WW2 but was not intended for combat use. Its function was to capture the outright air-speed record installed in a specially built aircraft known as the CS15.
The A.S.8 was a V-16 design with individual cylinders and 45 deg. between the banks. Bore and stroke were 140 X 140mm giving a swept volume of 34.5 litres.
As with the 24 cylinder A.S.6 seaplane engine, the A.S.8 was designed to turn counter-rotating propellers.
Info on the internal arrangements of this engine is hard to find. Did this engine have two, side-by-side crankshafts each driving a propeller or was it a conventional V-16; if so, then the reduction gears at the front must have been of unusual design?
Any information welcomed.

red admiral · 08-23-2008, 05:50 AM

CMASA CS.15

jerryw · 08-24-2008, 08:37 PM

Thank you Red Admiral but can you provide any proof of what you say? One of the patents filed by FIAT SPA clearly shows a 16-cylinder engine with two side-by side crankshafts.
Also, if it did have just one crank, how did they provide the drive for the two propellers?

kool kitty89 · 08-25-2008, 01:55 AM

For the props it should be similar to what those used with the Griffon, R-2800, and R-4360 etc. were equipped with on various projects durring WWII and post-war. (XB-35, YP-60, Seafang, etc) I believe were geared to be operated by a single shaft.

red admiral · 08-25-2008, 04:53 AM

I'm pretty sure from the arrangement of the A.38 engine which was based on the AS.8. This was definitely an inline V-16 and also had contra-rotating propellers. The drawing of the installation of the AS.8 above also looks like an inline V16. The contra-rotating propeller has a single input which drives the rear propeller. Then there is a gearing system (could just be a simple bevel gear) that moves the drive to the opposite direction of rotation driving the forward propeller.

Do you have a link to that patent? I had a quick search but couldn't find anything like it.

jerryw · 08-25-2008, 08:24 PM

The only reference I have to the Fiat A.S.8 that gives some description of the internals is by Coggi (Italian text). I've had this translated - the account is a bit vague and is not accompanied by any drawings.
The patent is GB 360,167 which can be downloaded free from the Espacenet site.
Drawing attached shows basic layout of the A.S.6 (two 12-cylinder engines in tandem) and the A.S.8(?) (two straight-8 engines, side-by-side)

red admiral · 08-31-2008, 04:47 PM

Thanks for that. Its quite an interesting arrangement. Have you any idea why the compressor casing is shaped so strangely?

jerryw · 10-03-2008, 06:46 PM

Never mind the compresser shape, Rear Admiral - we are still waiting for you to substantiate your claim that this engine had only one crankshaft!

If you can't prove it, remove it!!

red admiral · 10-05-2008, 05:37 AM

I don't have a great deal of information on the AS.8 to give a definite answer one way or the other. If the angle between the banks is 45° as in post #1 then I'd guess that its a conventional V16 as this is a nice balance angle for the arrangement and the angle between the banks in the patent drawing is not 45°

kool kitty89 · 10-05-2008, 07:01 PM

Looks to be about 30° in the patent.

The Red Baron · 11-14-2009, 01:12 PM

Quote:

Originally Posted by jerryw

The Fiat A.S.8 engine was designed and developed in Italy during the early years of WW2 but was not intended for combat use. Its function was to capture the outright air-speed record installed in a specially built aircraft known as the CS15.
The A.S.8 was a V-16 design with individual cylinders and 45 deg. between the banks. Bore and stroke were 140 X 140mm giving a swept volume of 34.5 litres.
As with the 24 cylinder A.S.6 seaplane engine, the A.S.8 was designed to turn counter-rotating propellers.
Info on the internal arrangements of this engine is hard to find. Did this engine have two, side-by-side crankshafts each driving a propeller or was it a conventional V-16; if so, then the reduction gears at the front must have been of unusual design?
Any information welcomed.

Salve, sono Italiano non parlo Inglese,
per caso mi sono imbattuto sul Vostro Forum e vedo che cercate info sul Fiat AS8

vi allego la scheda tecnica tratto dal libro "Aereonautica Italiana museo storico catalogo motori"

Buona lettura

Saluti

Marcogrifo · 11-14-2009, 06:49 PM

Quote:

Originally Posted by The Red Baron

Salve, sono Italiano non parlo Inglese,
per caso mi sono imbattuto sul Vostro Forum e vedo che cercate info sul Fiat AS8

vi allego la scheda tecnica tratto dal libro "Aereonautica Italiana museo storico catalogo motori"

Buona lettura

Saluti

Ciao Red Baron,
benvenuto

Grazie per quello che hai postato, è molto interessante e praticamente sconosciuto per me

Cercherò di tradurre l'articolo in inglese meglio che posso, per poi inserirlo nella discussione.

Ciao

For other people: Red Baron doesn't speak english well, so I'm going to translate for him the pages he posted and put them here as soon as possible (and the best I can

).

Cheers

jerryw · 11-15-2009, 04:12 AM

Ciao Marcogrifo,

Thank you for your offer to translate the Italian language posts.

These pages posted by "Red Baron" are very helpful. The little drawing of the crankshaft seems to indicate that there is only one in the engine rather than two as indicated in the patent filed by FIAT.

What we need now is a drawing to show the gears involved in transmitting the power to the two contra-rotating propellers. From the outside of the engine, it looks as if it is a very symmetrical arrangement.

The Red Baron · 11-15-2009, 04:28 AM

Salve Marcogrifo,

speravo di trovare qualcuno che parlava italiano, così da poter tradurre il tutto!

anche io sono superappassionato di aerei , motori e tutto ciò che è scienza e tecnica

peccato che con l'inglese ho sempre avuto seri problemi, in realtà ne ho anche con l'italiano!

La scheda tecnica del Fiat AS8, l'ho presa dal manuale dei motori dell'aereonautica militare, al museo di "Vigna di Valle" vicino Bracciano RM

nel manuale ci sono descritti un centinaio di motori, anche a reazione tipo il J79 del' F104

al museo sono esposti anche vari motori tra cui il Fiat AS6 dell'idrovolante da corsa Macchi Castoldi MC72,
un vero spettacolo!!!

Ciao,

The Red Baron · 11-15-2009, 05:20 AM

Salve Jerryw,

se non ho capito male state cercando i meccanismi interni di trasmissione degli alberi controrotanti.

vi posto quelli del AS6 che equipaggiava il macchi MC72, sono uguali a quelli del AS8

spero di esservi stato utile
ciao,

08-25-2008, 01:55 AM	#4
kool kitty89 Senior Member Join Date: Aug 2007 Location: San Jose, CA Posts: 2,412	For the props it should be similar to what those used with the Griffon, R-2800, and R-4360 etc. were equipped with on various projects durring WWII and post-war. (XB-35, YP-60, Seafang, etc) I believe were geared to be operated by a single shaft. Last edited by kool kitty89; 08-25-2008 at 02:05 AM.

10-03-2008, 06:46 PM	#8
jerryw Member Join Date: May 2008 Location: Trentham, Victoria, AU Posts: 78	Fiat AS8 Never mind the compresser shape, Rear Admiral - we are still waiting for you to substantiate your claim that this engine had only one crankshaft! If you can't prove it, remove it!!

11-15-2009, 04:12 AM	#13
jerryw Member Join Date: May 2008 Location: Trentham, Victoria, AU Posts: 78	FIAT AS8 Ciao Marcogrifo, Thank you for your offer to translate the Italian language posts. These pages posted by "Red Baron" are very helpful. The little drawing of the crankshaft seems to indicate that there is only one in the engine rather than two as indicated in the patent filed by FIAT. What we need now is a drawing to show the gears involved in transmitting the power to the two contra-rotating propellers. From the outside of the engine, it looks as if it is a very symmetrical arrangement.

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08-24-2008, 08:37 PM	#3
jerryw Member Join Date: May 2008 Location: Trentham, Victoria, AU Posts: 78	Thank you Red Admiral but can you provide any proof of what you say? One of the patents filed by FIAT SPA clearly shows a 16-cylinder engine with two side-by side crankshafts. Also, if it did have just one crank, how did they provide the drive for the two propellers?

08-25-2008, 04:53 AM	#5
red admiral Senior Member Join Date: Mar 2005 Posts: 434	I'm pretty sure from the arrangement of the A.38 engine which was based on the AS.8. This was definitely an inline V-16 and also had contra-rotating propellers. The drawing of the installation of the AS.8 above also looks like an inline V16. The contra-rotating propeller has a single input which drives the rear propeller. Then there is a gearing system (could just be a simple bevel gear) that moves the drive to the opposite direction of rotation driving the forward propeller. Do you have a link to that patent? I had a quick search but couldn't find anything like it.

08-31-2008, 04:47 PM	#7
red admiral Senior Member Join Date: Mar 2005 Posts: 434	Thanks for that. Its quite an interesting arrangement. Have you any idea why the compressor casing is shaped so strangely?

10-05-2008, 05:37 AM	#9
red admiral Senior Member Join Date: Mar 2005 Posts: 434	I don't have a great deal of information on the AS.8 to give a definite answer one way or the other. If the angle between the banks is 45° as in post #1 then I'd guess that its a conventional V16 as this is a nice balance angle for the arrangement and the angle between the banks in the patent drawing is not 45°

10-05-2008, 07:01 PM	#10
kool kitty89 Senior Member Join Date: Aug 2007 Location: San Jose, CA Posts: 2,412	Looks to be about 30° in the patent.

11-15-2009, 04:28 AM	#14
The Red Baron Junior Member Join Date: Nov 2009 Posts: 4	Salve Marcogrifo, speravo di trovare qualcuno che parlava italiano, così da poter tradurre il tutto! anche io sono superappassionato di aerei , motori e tutto ciò che è scienza e tecnica peccato che con l'inglese ho sempre avuto seri problemi, in realtà ne ho anche con l'italiano! La scheda tecnica del Fiat AS8, l'ho presa dal manuale dei motori dell'aereonautica militare, al museo di "Vigna di Valle" vicino Bracciano RM nel manuale ci sono descritti un centinaio di motori, anche a reazione tipo il J79 del' F104 al museo sono esposti anche vari motori tra cui il Fiat AS6 dell'idrovolante da corsa Macchi Castoldi MC72, un vero spettacolo!!! Ciao,

11-15-2009, 05:20 AM	#15
The Red Baron Junior Member Join Date: Nov 2009 Posts: 4	Salve Jerryw, se non ho capito male state cercando i meccanismi interni di trasmissione degli alberi controrotanti. vi posto quelli del AS6 che equipaggiava il macchi MC72, sono uguali a quelli del AS8 spero di esservi stato utile ciao,