Surprise Startup

[Phil Coopy]

Some of you guys have probably had this happen before, but I thought I'd mention it because it's a first for me (in 55+ years).

Today at the field I was getting ready to launch.  I primed the engine, flipped it about 10 times, put on the battery...no bump yet.  Took off the battery primed a couple of more turns and then started flipping to get the prime into the cylinder, on about the third flip the engine came to life without the battery connected.  Surprise!

There are a couple of reasons this can happen but the point is, it can happen. And I'll be lookiing for it from now on.

Phil

[Derek Barry]

I have had this happen to me a lot of times. It is very hot here in the south and for me this is pretty common. I use a piece of coupling on my finger even when I am just priming my motor.

[Tim Wescott]

I developed a set of reflexes around model diesel engines -- namely to always assume they'll start up.  So I never casually 'flip' -- I flip with a glove on, or I grasp the prop like I'm feeling for a bump to turn it over.

[Wynn Robins]

All guns are loaded, all engines will start when flipped, except at contests.

Actually Ty, the start first time with all your practise flights at a contest - but after that.............

[Paul Taylor]

Phil,
What kind of engine was it?

[Phil Coopy]

Wynn,

It is a detuned LA46 with the compression lowered, on 10/22n fuel.  I think the plug was still hot after I disconnected the battery.

Phil

[Andrew Borgogna]

My ST 3000 did the same thing, thank God my son was holding the plane or that 18" prop would have gone right through my hand.
Andy

[Lester Nicholson]

Around 1976, while stationed in Korea, I had an R/C O.S. start in my hand, removed form the airplane, while flipping the prop, when showing it to a friend. It only ran for a 10th of a second or so. I let go of it real quick  -  Nick

[david beazley]

My R/C pylon partner had a Rossi .40 start while I was holding the plane with no battery connected at the 1988 Nats at Fentress in VA Beach.  The fuel was 15% nitro provided for the contest.  I have seen happen one other time since then.

[fred krueger]

I've had this happen quite a few times; 2 or 3 times at contests.  I've been informed (by a glow plug manufacturer) that this is due to a catalytic reaction of methanol with the platinum plug element.

Fred

[Steve Helmick]

FWIW, there's a thread on this subject in the Engine Setups & Tips forum, with 21 posts. Many safety suggestions and horror stories there.  Steve

[John Stiles]

I've had this happen quite a few times; 2 or 3 times at contests.  I've been informed (by a glow plug manufacturer) that this is due to a catalytic reaction of methanol with the platinum plug element.

Fred

I've had to clean my share of dried blood off several ringmasters! [I believe I have a movie on VHS somewhere of such an incident]

[Steve Helmick]

I was wondering if there would be a cause/effect with a new glowplug being installed, after reading Fred's post. My one occurrence was definitely not with a new glowplug...quite to the contrary, a rather elderly example with a season's use under its belt. The sudden start-up, while unexpected, didn't cause me any harm, due to being reasonably careful while doing the "flippity flippity flippity" drill  after the choking and before the planned starting event.

What did rather freak me out was how to shut the sucker down without making it not start again in short order, this being on an official flight, second round. I could have called an attempt, but there was time enough for that, in case it really wouldn't start again. With a clunk tank on muffler pressure, I pinched the pressure line off until it stopped lean, choked a few times and signaled the judges. Might not be a bad plan to practise emergency shutdown and restarting immediately. I'll put it on the list, if & when I can find the list.  Steve

[Elwyn Aud]

I had a 25FP that had stopped at top dead center. When I connected the battery the piston moved and it fired up.