Spitfire IIa prop pitch

[Kurfürst]

Originally Posted by Crumpp

NO...You have confused automatic devices.

The VDM hydraulic electric propellers are CSP in hydraulic mode and variable pitch in electric mode.

Schwarz-man, whom I know and he is correct in his explanation of how the SYSTEM works.

He is describing the interaction of the CSP PROPELLER with MANIFOLD PRESSURE of the ENGINE!!

This eliminated the pilot from having to adjust PROPELLER RPM as with ANY CSP and then have to adjust ENGINE MANIFOLD PRESSURE. It reduced his workload when compared to a using a CSP on regular aircraft engine with manual controls.

Yup, my understanding is that effectively the 109 Automatik is just the manifold pressure throttle linked to certain RPM, it keeps the

It wasn't fixed-pitch-to-certain-MAP since if you think about it - if *pitch* would be fixed, rpm would increase/decrease all the time as speed - and load on the propeller blades - would decrease/increase.

In essence its just a single lever CSP where you can set the rpm/map correctly quickly and convinient. You did not have to mind much how to set up the engine.

On Allied planes with CSP, you set the desired RPM and MAP seperately, and the system would keep the RPM constant, by adjusting the pitch as needed. You still had to set the optimal RPM/MAP combination manually, by using two seperate levers, and there was a bit of a backside, since you had to do this in correct order , IIRC/AFAIK for example when increasing power, first RPM needed to be increased with the RPM lever, then boost, otherwise you would run the engine at low rpm / high boost which would stress the engine. The downside was that it required more attention from the pilot, and a bit of extra work.*

This was not modelled correctly in old Il2, and I as I recall it still isn't in COD.

* later it seems that a simplistic mechanical "system" was introduced, according to later Spitfire manuals for example that mention interconnected control. This however I believe was fitted only the some later Mark batches - impossible to tell which ones and how many - and not all planes, and the system was merely a metal rod that ensured that if MAP was increased, the MAP lever grabbed the RPM lever and pushed it forward, too. But unlike on the 109, it did not give optimal rpm/map combinations on most of the lever movement range, it just enabled the pilot firewall the throttle quickly and push both rpm/map the maximum regime.