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-   -   Piston propeller check dilemma - which way? (https://www.pprune.org/tech-log/447005-piston-propeller-check-dilemma-way.html)

trex450 25th Apr 2011 19:01

If it is your own aircraft (mine had a 160hp lycoming) then I would pull through forwards. Only however for the first start of the day. It is very simple really, if there is some form of restriction in the movement that causes damage on start then the repair comes out of your pocket, or at least the hassle of insurance claims and time without an aircraft. Common sense always dictated that the prop was treated as live with the necessary precations therefore taken. Of course if it is your aircraft and you were the last to start it then you will have checked the mags on shut down so it is highly unlikely that they will have suddenly become live in between. If you are playing at this on subsequent starts then the engine may still be warm and the chance of it firing are higher.

Air Tourer 26th Apr 2011 10:58

I'm sure I've seen one or two hot engines kick over well after shut-down, luckily with no one in the way.

boofhead 27th Apr 2011 05:06

A mechanic can pull an engine through and by feel know that it is normal or otherwise. A pilot usually does not have that experience or ability. I never pulled the P&W 1830s through because they had an inertial starter that did that for me. The P&W 985 I do pull through because the manufacturer says to do it, even if the engine has a separate starter (not included on the ignition switch). It always feels wrong to start those engines that have been modified with a Cessna-type start switch.

rh200 27th Apr 2011 05:43

Many years ago I did my PPL with a very large well known aero club, never heard anything about turning over by hand. After a few check flights etc at other flying clubs, none there either. I would say in general it probally should be discoureged for obvious reasons. If you do an endorsment on a particular aircraft that requires it and its part of its published procedures, so be it.

IO540 27th Apr 2011 06:15


I've been taught not to turn engines backwards as it is not good for vane pumps, I have a suspicion that its just an old wives tale but just as a precaution I don't turn engines backwards
Most vac pumps for sale today (every 215CC one I have seen) are either bidirectional, or are OK to run in the wrong direction for something like 50hrs.

ZQA297/30 28th Apr 2011 17:28

How come "elf and safety" haven't banned propping yet?

cockney steve 28th Apr 2011 22:23

My friend's Aeronca didn't have any starter other than the "armstrong"-indeed, there were no electrics other than the mags!
Communications were latterly by Icom handheld, to ground, or loud yells for cockpit conversation.

Hand-starting is great fun and takes me back to my model-aircraft diesels in the early 60's........starting them was a one-finger affair, but you could get some nasty cuts if they kicked-back. :\

ZQA297/30 30th Apr 2011 15:49

@Steve.
for your pain, you got a good practical idea of what "hydraulicing" was.
Plus you could tell if an engine was rich or lean by the sound of the exhaust. Even more so on glo-plug engines.
Even worked on R2800 with open exhausts (DC-6), but NOT on Convair 440 because siamesed exhausts were fed into augmentor tubes which muffled everything. I was always much better at starting the DC-6 than the CV-440!

Piltdown Man 30th Apr 2011 17:21

I'd read the Pilot's Operating Handbook and do what it says in there. If it doesn't say "Swing the prop.", don't. Unfortunately, there are hundreds of "old wives tales" in aviation and it takes a bit of time to sort out the little golden nuggets from the big, pointy ended brown jobbies. One of the best sorting methods is to listen for the noise of condemnation. Normally the bigger the noise, the more likely it is that the person is feeding you crap.

PM

ZQA297/30 1st May 2011 17:02

I learned to fly on Auster Aiglets and Autocrats, which had no starter. Furthermore the engines were inverted inline fours and although dry sump, oil tended to slowly drip into the cylinders over time. They were usually pulled through a couple of times, then primed, then "contact" and off you went.

What you did learn was that you had to regard the prop as live at all times, only open the throttle "one knob" when ignition on, and make sure you had chocks that were designed for the aircraft they were being used on.

If you flooded the engine, you had to make sure mags off, open throttle fully, pull through, then close throttle to one knob and "contact".
Forgetting to close throttle was a big problem and I heard of several incidents where Tiger Moths jumped chocks and in one case took off and slowly spiralled in.
The idle at "one knob" was also a liability if the chocks were metal, or a bit too big for the wheel in question. I have been chased at a walking pace from light chocks on wet grass and "one knob". The aircraft just pushed the chocks along.
To sum it up in the words of 411A, dont do it unless the book says so. And then be very very careful.


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