Superchargers : switching gears at optimal altitudes.

[I./JG52_Woutwocampe]

Hello fellow pilots. 

 

I noticed that often, switching from gear 1 to gear 2 below the recommended alt still provided a significant MP increase.

 

For instance lets speak about the I-16. Switch alt is 3000m. But even at 2500m switching to gear 2 provides a good MP increase. So my question is, despite the noticeable increase of MP at 2500m, is the HP gain from the MP increase inferior to the HP loss that the 2nd gear leeches away from the engine compared to the first gear?

 

I'll throw some random numbers here.

 

I-16. Alt 2500m.

 

1st gear to 2nd gear, from 800mm of hg to 1000mm of hg which represents a gain of 120 hps.

 

1st gear costs 100 hps leeched away from the engine. 2nd gear costs 240 hps from the engine. A -140 differential.

 

That means that, at alt 2500m, the MP increase add 120 hps but I lose 140 hps because of the gear so OVERALL I lose 20 hps by switching.

 

 

I-16. 3000m alt

 

1st gear to 2nd gear. 720mm of hg to 1000mm of hg which represents a gain of 150 hps.

 

1st gear costs 100 hps leeched away from the engine. 2nd gear costs 240 hps from the engine. A -140 differential.

 

That means that, at alt 3000m, the MP increase add 150 hps but I lose 140 hps because of the gear so OVERALL I gain 10 hps by switching.

 

 

Am I understanding it correctly here?