cold start runaways

[Liquid Charlie]

The issue is too much throttle and a "runaway" start when the engine catches and it accelerates above a 1000 RPM in a fraction of a second. Even immediate pull back on the throttle is too late. The damage has already started. Think back, with an injected large flat engine this is not an unusual thing when hands are flying and you fucked up the initial prime and the mixture and throttle is being manipulated just to get the thing to fire. This is the pitfall most fall into and added the loss of patience and you have your ticking time bomb. This has nothing to do with taxi, run up or take off. This is the first second after fire cylinder fires.  It is a very difficult problem to solve because there are so many variables happening. No 2 engines are the same which adds to the mix.

[Colonel]

This is why I am such a huge fan of hand-bombing
the prop - it teaches you to prime precisely.

You teach someone how to prime correctly, they
will really reduce the wear and tear on the starter
and engine internals and reduce the risk of fire.

No one gives a shit about priming, but it's really
important.

[Four Bars]

Where would you apply the "mystery mist" to get the thing firing? Spray it right onto the intake filter?

[Colonel]

You betcha.

[digits]

What multigrade oil do you recommend I run in my pitts with O360 with high compression cylinders (for 200 hp instead of 180hp according to the book)? I fly my plane at temperatures of -10 celcius and above.

Previous owner only flew it in summer time and used W100 plus

[Colonel]

Aeroshell 15W50.  Better than that Phillips cat piss.  This
really has nothing to do with acro.

Hey, with a Pitts in the cold, you have to be worrying about
the oil breather vent icing over.  Weirdly, on a Pitts, the
breather vent does not exit in the engine cowling like a
normal airplane, it runs to the tail to deposit all the oil
on the tailwheel.  Curtis worried about the tailwheel
rusting, I guess.

And that's fine for Florida, but in Canada, you have to
expect the oil breather tube exit at the tail to ice over
and you need a vent forward of the firewall opened
up, otherwise you blow the front crank seal, which
is very very bad.

Aviat has a whiffle valve, but you can drill a hole
in the top of the flange fitting and slide the tube
forward in the winter.  A mess in the cowling is
better than all your oil on your windshield.

Some guys run the oil breather tube to the
exhaust but you have to worry about excessive
suction from the exhaust.  Careful there.

[Colonel]

Moment of irony:  you are getting winter ops advice
from someone who lives where it never gets cold.

[digits]

Thanks!

I already drilled the hole in the breather tube last winter based on your earlier posts. Was kind of interesting to put a drill into my new (used) airplane  ^-^

[Colonel]

Free advice:  You don't always get to fly your Pitts in Canada
in winter as often as you'd like to.

With that in mind, toss a pint of Camguard into the oil, and
put a battery tender on [i]every time[/i] you park your airplane.

[img]https://i5.walmartimages.com/asr/a323b8 ... nBg=FFFFFF[/img]

Those two easy things will make an enormous difference.

PS All you need is the cheap $30 3/4 amp "junior" version.

Fuck, I gotta get both those guys to sponsor me.