engine ops at < 1G flight

clam · #1 09-22-2009, 09:01 AM

For the operators flying: fuel injected, no inverted oil or fuel systems, what are your engine operating limitations (ie, time and g limits for fuel & oil press) for typical IO-360/375?

Thanks

David-aviator · #2 09-22-2009, 09:48 AM

Quote:

Originally Posted by clam

For the operators flying: fuel injected, no inverted oil or fuel systems, what are your engine operating limitations (ie, time and g limits for fuel & oil press) for typical IO-360/375?

Thanks

A long time ago I attempted a decent looking loop with a little forward stick at the top. Quite a bit of oil ended up on the outside of the airplane and much time to clean it up.

In retrospect, it was a dumb thing to do, haven't thought of doing it again since.

Just call me
positive G.

Andy_RR · #3 09-22-2009, 10:57 AM

Has anyone ever dry-sumped a lycoming? I've searched a bit on Google et al, but not found any meaningful leads.

What do the Reno guys do?

Cheers,

A

PS I know that Lyc have dry-sumped the IO-233 - that's probably how they "get the weight out" of the engine - just move it to the firewall!

SteinAir · #4 09-22-2009, 04:42 PM

Quote:

Originally Posted by Andy_RR

Has anyone ever dry-sumped a lycoming? I've searched a bit on Google et al, but not found any meaningful leads.

What do the Reno guys do?

Cheers,

A

PS I know that Lyc have dry-sumped the IO-233 - that's probably how they "get the weight out" of the engine - just move it to the firewall!

Some of the original AIO's were dry sumped, some of the heli engines were dry sumped. The Christen inverted oil system takes care of the puking oil in inverted flight as well...to me that would be a lot easier of an installation that trying to re-invent some sort of dry sump system.

The reno guys are almost always pulling a fair amount of positive G's around the oval.

Cheers,
Stein

Jamie · #5 09-22-2009, 05:17 PM

I have found no problems at all operating from 0.1-1.0 Gs.

mannanj · #6 09-22-2009, 07:30 PM

Quote:

Originally Posted by clam

For the operators flying: fuel injected, no inverted oil or fuel systems, what are your engine operating limitations (ie, time and g limits for fuel & oil press) for typical IO-360/375?

Thanks

IIRC, Lycoming limits negative G's to 30 seconds on it's non aerobatic (ie. O- and IO-360-XXX) wet sump engines.

N941WR · #7 09-22-2009, 07:46 PM

Quote:

Originally Posted by Andy_RR

...PS I know that Lyc have dry-sumped the IO-233 - that's probably how they "get the weight out" of the engine - just move it to the firewall!

Andy,

Take a nother look at this drawing from Lycoming. The IO-233 does have an oil sump, it is just a little bit different than what we are used to.

Andy_RR · #8 09-23-2009, 01:51 AM

Thanks Bill - I stand corrected. I had read somewhere in the media that the 233 had been dry-sumped, but possibly it was just journalistic license!

Andy Hill · #9 09-23-2009, 02:51 AM

Jeff...

Our RV-8 has XP-IO-360. No inverted fuel (i.e. no Flop Tubes) and only the breather half of a Raven Inverted system i.e. to catch / return Oil to sump, no effect on maintaining Oil Pressure.

We work to limiting the Oil Pressure decrease to, I would say, 3-4s - any more and the Oil P gets low, and the Prop starts speeding up. Effectively you can do 1 slow / hesitation roll, but no sustained inverted or "push" manoeuvres.

I have flown an identical RV-8 with full Inverted Oil and 1 Flop Tube. With the other tank selected, it ran inverted for 23s at 24x24 before "coughing".

Hope of some use...

Andy & Ellie Hill
RV-8 G-HILZ

breister · #10 09-23-2009, 08:32 AM

The difference between 0.1g and -0.1g is very subtle (especially if you are strapped tightly in) - but as long as you stay positive all the oil should stay where it belongs.

If you really want to get your nose down faster (from an appropriate altitide), just roll in 120-180 degrees of bank and pull a little. That's way more fun than pushing negative g's...