Prop Unfeathering Accumulators - Question

[mshac]

I've enjoyed my twins in the past that had unfeathering accumulators.

With accumulators, its much smoother to restart an engine after practicing single engine work. Just push the prop lever forward, give the motor some throttle and mixture, and its immediately running smoothly again. Without accumulators, the engine shakes badly when you start it using the starter, which is the only option you have if the prop is feathered. Hard on the starter, hard on the prop, hard on the Lord mounts, and hard on the crew.

This is one reason most training these days is "zero thrust" where the ME instructor "simulates" an engine out by reducing MP to 12". The motor never actually gets shut down. That's fine and dandy for flight school safety, but that training method cannot, and does not, demonstrate the actual immediate loss of performance with a windmilling prop and a dead engine. I want to train under real-world conditions with the dead engine windmilling, so if it does happen in real life, I've seen it before, and know what to do. So...

I'd like to install accumulators. I can buy a set for well under $1k, and they don't weigh very much. The service manual doesn't show exactly where the accumulators are mounted.

Would one you guys with accumulators installed post a few pics of them, both front and rear, so I can get an idea of where the factory mounted them?

[Frank Benvin]

Here is the page from my parts manual 1967 337b

[mshac]

Originally Posted by Frank Benvin

Here is the page from my parts manual 1967 337b

Thanks Frank. My manual is similar to yours.

I can see that the rear is mounted on the engine mount frame somewhere (with what appear to be hose clamps), but the front doesn't give much reference to where its installed.

Actual photos is what Id really love to see!

[mshac]

Actually, it looks it would require special governors as well as the accumulators, so I guess I'll just deal with the "shaky start up" upon unfeathering. Not willing to spend $3k on this little "improvement".

They were standard on O2s. If I were getting shot at, I'd want them for sure. The seconds they save on restart could save your life!

If I was gonna do ME flight training on a regular basis in it, I'd still consider them though.

[hharney]

Most of the accumulators on these planes were removed back in the day. No one wanted the maintain them and they just weren't needed. The start up isn't so bad without them and just go easy on the starter when you do this. Make sure you follow the procedure in the book for in flight restart, works like a charm

[Jhogan0101]

Here is one with accumulators trying to restart front engine.
@ 7:30

https://youtu.be/tAB486BKI10