Dive Engine Management

[HR-Crumble]

Hi all,

 

Recently got back into the Jug after a few years off warbirds. I dusted off my old flight notes and I’m comfortable again with T/O, climb and cruise settings etc. Diving however I keep blowing the engine. 
 

What are the correct dive engine management settings for a fast dive from high altitude 20K? 
 

I can’t see anything in the manual or chucks. 
 

Cheers!

[grafspee]

First of all, you should track what actually is killing engine, but i assume that excessive rpm is reason why engine dies, then if you want make high speed dives in P-47 only way to contain rpm within limits is switching to manual pitch control and keep rpm within limits manually. Reducing rpm in automatic mode does little to help that issue because no matter what rpm you set via prop lever, max pitch for prop remains exactly the same and engine will overspeed above 2700rpm at exactly same speed regardless of prop lever position. If it is not rpm issue then some replay track will come handy. 

Edited June 28 by grafspee

[Aernov]

Just did a "test flight" during which I tried different engine operating conditions as described in manuals (2550 RPM-42'' MP, 2700 RPM-52'' MP, 2300-35'', 2070-31'', including war emergency with water injection, 2700-64''). All within time limits and even within oil temperature and CHT limits for the entire duration of flight (95° oil for some time, but it is still within limit). After trying different engine settings I did a dive from 16000 to about 3000, during which I kept RPM below 2700, but for a short time I probably got some windmilling going on (MP was about 25'' with RPM close to 2700). And the engine died soon after this dive (within minute(s), with all parameters in safe margins, only oil temp started rising above 100° as the engine lost all power). Damage report said "engine degraded". Were crankshaft bearings really this fragile?

P-47 Engine degraded.trk

[HR-Crumble]

On 6/28/2025 at 11:39 PM, grafspee said:

First of all, you should track what actually is killing engine, but i assume that excessive rpm is reason why engine dies, then if you want make high speed dives in P-47 only way to contain rpm within limits is switching to manual pitch control and keep rpm within limits manually. Reducing rpm in automatic mode does little to help that issue because no matter what rpm you set via prop lever, max pitch for prop remains exactly the same and engine will overspeed above 2700rpm at exactly same speed regardless of prop lever position. If it is not rpm issue then some replay track will come handy. 

So what are your dive engine settings then?