Hand Starting a 912?

[Glenn Wilson]

I was told the other week that you can't hand start a 912. The explanation given was that with the reduction gearbox..........

 

Not had too much experience with them but I know how easily the O300 I used to sit behind used to pop into life with a well timed pull on the prop.

 

What's the verdict? Am I being fed a porky or does this person's idea hold merit?

 

ps, this came about while he was turning the prop over without checking ignition and/or master switches.

 

 

[Happyflyer]

I was told the other week that you can't hand start a 912. The explanation given was that with the reduction gearbox..........Not had too much experience with them but I know how easily the O300 I used to sit behind used to pop into life with a well timed pull on the prop.

 

What's the verdict? Am I being fed a porky or does this person's idea hold merit?

 

ps, this came about while he was turning the prop over without checking ignition and/or master switches.

It's been discussed before. Check here Rotax hand start?

 

 

[cscotthendry]

Short answer is "Yes" a 912 can be hand propped, but it takes a bit of doing. There is a video on YouTube showing a guy doing it.

 

 

[Glenn Wilson]

It's been discussed before. Check here Rotax hand start?

The other thread didn't really come to any conclusion - just a bunch of opinions and a video of a guy doing it. From what I make of all that is, yes, they can be hand started.

 

 

[Keenaviator]

Impulse coupling helps - that's something both good and bad about magnetos.

 

 

[Downunder]

I believe the 912 will not "fire" until 200 rpm has been achieved. Something built into the modules.......

 

I've seen a few turn over half heartedly and then fire instantly when a new battery or jump start has been performed.

 

I'm not sure whats going on with that video. Perhaps an older engine with "original" modules?

 

It is also an 80 hp, with far lower compression than a 100.

 

 

[kasper]

I believe the 912 will not "fire" until 200 rpm has been achieved. Something built into the modules.......I've seen a few turn over half heartedly and then fire instantly when a new battery or jump start has been performed.

I'm not sure whats going on with that video. Perhaps an older engine with "original" modules?

 

It is also an 80 hp, with far lower compression than a 100.

Hi, posted on the other thread but to be clear - Both the 80 and 100 r912 can be hand propped. Done both personally.

 

Unlike 'old' aero engine with impulse spring on one mag to make hand starting easy all r912 have electronic box ignition that DO NOT fire at very low revs so to hand prop a 912 you really have to mean to start them.

 

If you are just pulling through to gurgling the engine you are not going to get a spark firing BUT having said that you should always treat all props as potentially live because you might just forget and do it on an engine (not r912) that has an impluse coupler or one that has been modded eg my hirth f23 with complete aftermarket ignition that replaced the box with one that will fire on first prop blade movement.

 

 

[rgmwa]

This should work:

 

 

 

[Callahan]

We did that in Mexico on a Piper Aztec using a truck. Worked great.

 

A little off topic but I used to own a Howard DGA with a 600 hp R1340. Only one ever remodeled with that motor. I was cranking up at a crop duster strip one hot day in the southern U.S. Battery decides it ain't gonna' crank. Out pops a big burly old crop duster. Now, this motor sits way up so he had to reach way up.... dangerous!....I told him no, he said yes, reached up there, pulled that Sumbitch through....it cranked on first pull. Scared me just watching what I could see of him from the cockpit!

 

 

[Doug Evans]

Yes you can ,

 

 

 

[Doug Evans]

[Callahan]

Well done Doug! Alwats treat it as if it's hot.Here's a couple of brief but good hand propping stories over the past 45 years.

 

Me & a 65 hp Drifter: Took off, got to 300 ft., motor quit, landed okay, got out, went to back, scratched my stupid head thinking "I wonder if this sumbitch will crank?" Remember I had just taken off..... hint, hint, hint......motor cranked.....at full takeoff power. Horizontal stabilizer hit me, knocked me down but I managed to grab its leading edge. You will not believe the power of 65 horses until you're being rapidly drug behind them in a multiple circles. I was helpless. Totally. Coming around on the 4th quick whip around with hand grip weakening, i noticed tall, thick brush alongside the runway, timed it good, let go, it took off, climbed to 6 or 8 feet, crashed into brush & stopped. No damage except a bent pitot.

 

This one is funnier. I have it on video. I was hand propping a 52 hp Rotax, Phantom (tractor configuration). Friend of mine, as stupid as I am, was sitting in the cockpit & supposedly telling me if it was hot or not. I propped & propped & propped & propped till I was about to drop dead. I finally was smart enough to ask "Is it hot?"

 

"No."

 

He wasn't looking at the mag switches as he went back & forth numerous times. Communications had broken down during a difficult start on a hot, miserable day. Make damn sure you're communicating correctly! And ALWAYS TREAT IT AS HOT.