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Oil accumulator explosion

J.D

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IFR southbound climbing through 11K west of reno NV when a loud bang up front gets my immediate attention, when my voice returned I let center know I may have to dive in to reno. As everything sounded ok and all gauges were in the green I proceeded south while trying to figure what caused the loud bang.

To make a long story short the top had blown out of the moroso tank, I had left the valve closed when starting fortunately or all the oil would have been pumped out.

This just happened two days ago when I have more information I'll let everyone know also will post pictures as soon as I figure out how.

J.D
 
Locked Up Oil

To make a long story short the top had blown out of the moroso tank, I had left the valve closed when starting fortunately or all the oil would have been pumped out.

J.D

If the accumulator was full of cold oil prior to flight without adequate expansion volume (ullage) and the isolation valve remained closed after engine start then during flight as the accumulator warmed to engine compartment temperature, the oil had no place to go as it heated and expanded. This caused over pressurization of the cylinder and the resultant failure. It sounds like this setup needs a pressure relief valve that bypasses the isolation valve.

Skylor
 
Sorry, but

I do not know what a moroso tank is or what an oil accumulator is doing on an RV --

Can someone enlighten me, please?

Thanks,

Ron

Edit: ---- I read the other posts ---- thank you ----- very helpful.
 
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The Canton Accusumps are better, they come with a relief valve for exactly this purpose.

The accumulator is used instead of an inverted system. They're simpler and more reliable if properly set up.
 
accumulator

So how much inverted time can you fly with one? Sounds like the perfect solution for some occasional acro.
 
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accumulator tank

Actually I have an inverted oil system also, the accumulator tank just keeps oil pressure up all the time no momentary blurps to cause a dynon alarm. It's also a good way to pre-oil before startup assuming you open the valve.

J.D
 
You may be correct with the cold oil theory althought this system has an air chamber on one end which should prevent this.

Thanks
J.D
 
I do not know what a moroso tank is or what an oil accumulator is doing on an RV --

Can someone enlighten me, please?

Thanks,

Ron

HERE is an old thread which describes the half Raven system and oil acccumulator that I used before going to a full inverted system. I still use the accoumulator to keep pressure up during zero "G" maneuvering when the inverted system check valve ball isn't seated in either the upright or inverted position. I found that the accumulator gave me about seven seconds of oil pressure.
 
Ron

Did you ever put a valve on the accumulator tank?

J.D

No. The only useful purpose for a valve is to capture oil in the accumulator prior to shutdown so that you can use it to pre-oil the engine prior to the next start. That might be helpful if you only flew your airplane once a month. I put nearly 300 hours/year on mine so dry bearings are not an issue. YMMV
 
J.D.,
Would you be able to post some pictures of your installation? I'm interested in doing the same thing for my radial. Thanks....
 
Although not on an airplane I used on of these on a street/race car where I was having oiling issues on the track where it would pump it up and not drain back in time, split second of no pressure and motor was gone.

Acculmulator solved this in a hurry, always stable oil pressure and didn't hurt a motor from lack of pressure since.
 
No. The only useful purpose for a valve is to capture oil in the accumulator prior to shutdown so that you can use it to pre-oil the engine prior to the next start. That might be helpful if you only flew your airplane once a month. I put nearly 300 hours/year on mine so dry bearings are not an issue. YMMV

One bad thing about doing that (no valve) is when your engine starts, quite a bit of the oil is diverted to the accumulator and is starving the engine of oil when it needs it the most. On some airplanes I've flown such as the T-6 you start with the prop at low pitch for the same reason, to keep the propeller from starving the engine of the oil as the system is pressurizing.
 
For a pre-oiler, the Oilamatic one is an electric oil pump. I've got one on my Cessna 180. It reliably gives me oil pressure before hitting the starter, as well as lubrication for those times when I want to turn prop on the ground, e.g., during compression check.

It's an alternative to an accumulator for pre-oiling purposes.

Dave
 
rocketbob

You correct, if I forget to close the valve before shutting down, during the next startup it takes noticably longer for oil pressure to come up if I don't close it before starting.

J.D
 
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