hand propping an O320

andrsnj · #1 12-27-2005, 05:06 AM

I have hand propped a Continental O300 without any problems. That engine has significantly smaller cylinders than an O320 Lycoming though. What is the opinion out there on hand Propping a Lycoming O320?

Mel · #2 12-27-2005, 09:11 AM

Hand propping an O-320 is not normally a problem, providing that the prop is "clocked" correctly and the compression has not been increased dramatically. My O-320 originally had a compression ratio of 7:1 (150hp). When I rebuilt the engine I increased the ratio to 9.5:1. I hand propped it once after that and will not again. Of course I have also now changed to a 3-blade prop making it even more exciting.
Mel...DAR

osxuser · #3 12-27-2005, 08:40 PM

I have tried to hand-prop out C177 (O-360 8.7:1 compression) without much luck. I can't get it to go all the way around. It might be just 'cause I'm a wimp.

Jerry Kinman · #4 12-27-2005, 09:10 PM

Good advice about the wood prop and proper clocking. The engine/cylinder size is not as big a factor as simply doing it the correct way. My advice is to find someone with wrinkles, gray hair and preferably a member of the Antique Aircraft Association who will show you how to safely do it. I logged over 400 hours before I moved up to an airplane with an electrical system and after 40+ years I have hand propped engines ranging from a 65 hp Luscombe to a 450 hp BT-13 with nary a problem but I thankfully learned it from someone much older and wiser than me.

joe gremlin · #5 12-28-2005, 12:22 AM

Jerry's right. I've propped O-360's without a problem and I've seen IO-540s propped as well as 450hp Pratt radials. But I was taught by an old gray haired guy and I saw old gray haired guys prop the bigger engines. It can be done but it's a risk and it ain't easy so why would you want to if you didn't have to?

garnt.piper · #6 12-28-2005, 01:43 AM

I have an RV-4 with O-360-A1A, twin slick mags and ellison and wood prop. My starter has quit and I have been handpropping for the last month or two. I have no problems, I prime and wind prop back 8 blades, set throttle ~1/8" open and LH mag to ON, and can usually start it 3rd swing, hot or cold. It is more prone to flood hot, if it's a quick turnaround I won't prime, but will ensure the fuel system is pressurized and still wind prop back 8 blades before attempting a start. I've had some experience with Tiger Moths prior, but that is all.

andrsnj · #7 12-28-2005, 09:00 AM

I do plan on installing a starter. The only times I hand propped my 172 was when my battery was dead and that will probably be the only reason I will do it in my RV4. There is a large incentive to start your engine when you're stuck somewhere.

osxuser · #8 12-28-2005, 09:29 PM

I've been trained (A&P) and could do the R-985 (Beech 18), but can't get enough intertia in the angle of blades on the Cardinal. Another advantage of taildraggers is that they are easier to prop.

mikeflys8 · #9 12-29-2005, 05:58 AM

Years ago on a fly date to Calloway Gardens, late Sunday evening couldn't start the six that I was flying. After tying down and sitting proper throttle I actually proped a 250 hp. Never would want to do that one again...pretty sure it had fairly low compression also. It can be done.
Mike

jbDC9 · #10 01-02-2006, 11:23 PM

Just once, I hand propped a BE-58 (IO-520, 285hp, 3 blade prop)... was kinda scary, wouldn't want to do it again, but it was actually just about the easiest hand prop I've done. I just pushed a blade over, fairly slowly, and the thing cranked right up. Good thing the starter on the other engine was still working...

Like Mel said, an O-320 is easy if the prop is clocked correctly.

John
RV-8
Finish/FWF