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Playing in the Sandbox Group Build Sept 1, 2024 - Jn 1, 2025

Supercharger intakes... where are they?


GazzaS

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We all know that most German planes had a big supercharger intake on the port side.  But I don't see such things on P-51's and Spits.  Where's the air coming in at?  I know some planes had exhaust driven superchargers...   But I don;t think the two planes mentioned do.

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19 hours ago, GazzaS said:

 

We all know that most German planes had a big supercharger intake on the port side.  But I don't see such things on P-51's and Spits.  Where's the air coming in at?  I know some planes had exhaust driven superchargers...   But I don;t think the two planes mentioned do.

Ok Gazza ...

A minor correction ... Two types of "charging" the engine - otherwise known as forced induction ...

Well, strictly speaking there is a third, but that pretty much falls under the umbrella of "naturally aspirated" - A ram scoop seen on the bonnet/hood of many high performance motor vehicles - since the engine is still sucking the air in, even though it is being forced by "ramming" the air into the intake by speed of the vehicle.

Supercharging ... Mechanically driven impeller usually either by belts running directly off a crank pulley or gear driven off the crank.

Turbocharging ... use of expelled exhaust gasses to drive an impeller which in turn drives a compressor - forcing air into the engine.

The difference in application amounts to efficient transfer of energy - Supercharging is a more direct energy transfer - the more the engine revs the more the impeller spins - in direct ratio. With turbocharging there is always a "lag" factor ... you have to wait for exhaust gas pressure to spin up the impeller ... in a lot of ways its a cheaper method of forced induction - but not as efficient as supercharging.

In some modern applications a combination of both is used - as with my previous car - a Ford Fiesta ST with an Ecoboost engine ...

Down to business ...

Here is a Merlin engine showing where the air intake is ... on the back of the engine drawing air from the bottom - underneath the cowl ...

juxMCvi.jpg

 

Here is a photo of the actual part attached to the superchargers impeller casing ...

JZPfKra.jpg

And finally here is the intake on the underside of the cowl ...

9sryKBh.jpg

Hope that all makes sense for you mate?

Rog :)

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16 hours ago, Artful69 said:

Ok Gazza ...

A minor correction ... Two types of "charging" the engine - otherwise known as forced induction ...

Well, strictly speaking there is a third, but that pretty much falls under the umbrella of "naturally aspirated" - A ram scoop seen on the bonnet/hood of many high performance motor vehicles - since the engine is still sucking the air in, even though it is being forced by "ramming" the air into the intake by speed of the vehicle.

Supercharging ... Mechanically driven impeller usually either by belts running directly off a crank pulley or gear driven off the crank.

Turbocharging ... use of expelled exhaust gasses to drive an impeller which in turn drives a compressor - forcing air into the engine.

The difference in application amounts to efficient transfer of energy - Supercharging is a more direct energy transfer - the more the engine revs the more the impeller spins - in direct ratio. With turbocharging there is always a "lag" factor ... you have to wait for exhaust gas pressure to spin up the impeller ... in a lot of ways its a cheaper method of forced induction - but not as efficient as supercharging.

In some modern applications a combination of both is used - as with my previous car - a Ford Fiesta ST with an Ecoboost engine ...

Down to business ...

Here is a Merlin engine showing where the air intake is ... on the back of the engine drawing air from the bottom - underneath the cowl ...

juxMCvi.jpg

 

Here is a photo of the actual part attached to the superchargers impeller casing ...

JZPfKra.jpg

And finally here is the intake on the underside of the cowl ...

9sryKBh.jpg

Hope that all makes sense for you mate?

Rog :)

That makes great sense to me Rog.   Thank you very much.

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30 minutes ago, GazzaS said:

Thank you, Martin.  Now...   does this mean that all other cooling is done by that big scoop under the belly?

The big scoop under the belly was for radiator and oil cooler airflow …

9EAD273A-4C47-4DC0-BF11-4BE3BBD17057.jpeg.51a12862b9a90a60476094c3df85ea5e.jpeg

 

Meanwhile here’s another pic of the supercharger intake for the P-51

2BAF38A5-C952-45B8-BAFE-D076C12FC4A6.thumb.jpeg.3edb4e4550b714eab717c605fa56684a.jpeg

Rog

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