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Hand propping while keeping all my fingers

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Hand propping while keeping all my fingers

Old 13th Dec 2015, 21:38
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Hand propping while keeping all my fingers

Now that the slow starting, battery draining winter weather is here does anyone want to take a stab at the correct procedure for hand propping a bog standard C172 for example, for a cold morning first start of the day? Step be step procedure would be nice as I'm sure some of us will be faced with this terrifying task sometime this winter.
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Old 13th Dec 2015, 22:12
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For a Lycoming O 320 powered C 172 and an OAT of around + 5 C

1) tail tied down if possible
2) chocks on both main wheels
3) a qualified individual in the pilots seat
4) call throttle idle, mixture rich, mags off
5) look in the window and verify mags off
6) call 2 shots of prime
7) pull prop through 3 full turns
8) set prop at a comfortable angle ( prop tilted up about 30 degrees from the horizontal on the side of the downgoing blade, ie the one you are pulling on)
9) call for one shot of prime
10) call mags on brakes on.
11) swing prop, the engine will usually start immediately
12) if no start call mags off visual check and re position prop
13) call mags on brakes on try again

Notes:

a). You can hand prop by standing in front of, or behind prop. Personally
I like to stand behind the prop on the right side of the aircraft and hold on to the fuel step hand hold on the upper cowl with my left hand and swing the prop with my right.

b) a sturdy close fitting glove saves the skin on your fingers

c) only wrap the end of your fingers around the blade

d) make sure that the ground you are standing on gives you good footing

e) When swinging make a hard sharp pull and then relax your fingers and let your arm swing clear as the prop starts swinging

f) Anytime you move the prop assume the engine will start and position your hands and body appropriately
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Old 13th Dec 2015, 22:36
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Based on that list, attempting it solo would obviously be a big no no, as is trying it with only one qualified individual, usually yourself, in the plane leaving the pax to do the propping which is probably a non starter (pun intended) for most pilots. So you really need 2 qualified folks to do it safely.
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Old 13th Dec 2015, 23:41
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Better to keep the battery properly charged and to have a jumpstart available. There are proper ground power kits available for the purpose.

If your battery cannot start the engine there is a good chance that it will let you down in the air with no radio or transponder and only vacuum instruments.
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Old 14th Dec 2015, 00:24
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It has been years since I did that in Alaska in the winter, but I seem to remember we pulled the prop backwards several times to loosen up the oil before we attempted start...?
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Old 14th Dec 2015, 02:09
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What Big Pistons said, but to add that if you have run the battery flat trying to start a Lycoming, the bendix in the starter might still be engaged to the ring gear, in which case, hand propping it is not going to work.

Presuming the opportunity to get to know how that engine likes to be started, set it up that way before you begin. Pre heat it.

A few days ago, my 150's battery was low. I chocked and tied it, and as I expected, it was running on the third pull (it never fires on the forst two pulls - I just know). No drama, I cautiously walked around to set the engine running nicely, then all things well, untied and unchocked it, and off I went.

BUT, I'm hyper cautious hand propping planes I do not know - too many surprises. While hand propping a buddy's new 150 decades ago, having called mags off, which he acknowledged from the pilot's seat, I pulled through a prime. It started first pull. Fortunately, I always pull like it's gonna start. This time it did . I gave him a gesture of dissatisfaction through the prop arc. He responded by holding up the keys for me to see. A bad mag lead. Know your plane....
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Old 14th Dec 2015, 02:20
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As far as the mechanics of swinging the prop, I was taught this way:
http://youtu.be/ivCazXU-0kA

I have only propped one O-320, on a PA18. Not as much fun as the little continentals.
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Old 14th Dec 2015, 09:25
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What Big Pistons said. I don't like hand propping 172s or 150 but have done. We used always hand-prop the L4 Cub - there was no other way and it felt fine, as did the Chipmunk which we often hand propped first start of the day to save straining the small batteries.

I understand you should not turn some flat engines backwards as it knackers the vacuum pump.
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Old 14th Dec 2015, 09:38
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Treat the prop like the Queen. Never turn your back on it.
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Old 14th Dec 2015, 10:45
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First I would say get someone who knows to show you how to do it, either way, first practice with the mags off, noting where your hands and the rest of your body goes as you do it. Another point is to make sure you are on solid ground, easy to find at this time of year that you are standing on a slippery area of mud!
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Old 14th Dec 2015, 10:51
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As far as the mechanics of swinging the prop, I was taught this way:
http://youtu.be/ivCazXU-0kA
It seems that an essential part of the process is raising your right leg off the ground.....
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Old 14th Dec 2015, 10:52
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Don't move the propeller with the fuel on!
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Old 14th Dec 2015, 11:12
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Firstly you need extra care if you are hand-propping most (no offence intended) "Spam Cans" as the engine goes through TDC with the prop blade at around 7 o'clock - compared to something like a Tiger Moth where it does through TDC at around 2 o'clock.
This means (simple mechanics) there is a tendancy to start leaning into the prop (7 o'clock) at the point the engine is likely to fire - as opposed to leaning away (2 o'clock).

Secondly there should be no need for "sharply", or anything else which requires sudden effort (which will tend to unbalance you) - if the impulse mag is working the engine just needs to be brought gently past TDC.
If the impulse mag is not working correctly (you should be able to hear it "clack") then DON'T HAND PROP (unless you REALLY know what you are doing).

See this video: https://m.youtube.com/watch?v=mC9_1fxueqM

2 points to note:
  • On the first 2 pull throughs you can hear the impulse mag "clack". Note how gently the prop was moved - if the mags were on then it could (would?) have started
  • When he pulls it over with mags on he is moving away as he pulls through
  • Although he pulls it over slightly quicker with the mags on - there was no need

The process (for a Tiger Moth):
  • Check chocks are in
  • Check firm footing where you are going to stand (especially in wet weather on grass)
  • Fuel On
  • Prime (push button on carb until it dribbles av-gas on your feet)
  • Throttle closed
  • Mags OFF
  • Pull through 4 blades - TREATING IT LIKE IT WILL START
  • Throttle set
  • Mags On
  • Continue pulling though until it starts

If it doesn't start after 8-10 blades then it's possibly flooded:
  • Mags Off
  • Throttle Wide
  • Pull thought 12 (min) blades BACKWARDS
  • Start all over again (without the priming)

To give some "colour" to my experience ...
I learnt to hand-prop with the Tiger Club - where being able to hand-prop was a requirement before soloing the club planes (fairly necessary, since most of them don't have starter motors).

OC619

P.S. I realise that people are going to disagree with some/all of what I've written (as is their right) - in my defence: I have been hand-propping for 10 years and still have all my fingers
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Old 14th Dec 2015, 11:13
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1. Ensure aircraft on firm level ground.

2. Brakes on and set.

3. Throttle open 1/4"

4. Switches off. Keys in pocket.

5. Pull through four blades to break oil seal.

6. Fuel on.

7. Prime.

8. Pull through four blades.

9. Check brakes again. Physically by trying to push the aircraft against them.

10. Check throttle open 1/4". Again!

11. Switches on.

12. Swing smartly through one compression.

If it doesn't start then switches off, reposition prop and repeat steps 9-12. Perhaps with a little of step 7. Re-Prime.

It may take a few spluttering attempts to get some heat into the cylinders and inlet to aid fuel atomisation.

Good luck.

Just a quick comment about turning the engine backwards to "blow out" if flooded. DONT. If it is fitted with a vacuum pump. Possibility you may damage the graphite vanes of the pump.
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Old 14th Dec 2015, 12:22
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A couple of tips if you are going to prop it with no one in the cockpit, the first point being - DON'T
If you still go ahead like this then after priming, turn the fuel OFF, if it starts no problem there is plenty of time to go in the cockpit and turn it on before he engine stops due to fuel starvation, if for some reason the aircraft runs away at least it will run out of fuel after a few minutes!
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Old 14th Dec 2015, 13:02
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Perhaps someone can explain this one to me. A few years ago I got stuck at an airfield with a knackered starter solenoid, a local aircraft mechanic come over and said he would prop it for me, however prior to getting started and after making sure the magnetos etc. were all off, he ran the prop thru a couple of cycles listening for the impulse click and noting the position of the prop. I cant remember exactly what he said bit it was something along the lines of he was checking to see that the prop had been installed in the correct position i.e. installed correctly for hand propping in relation to TDC. Does this makes sense?
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Old 14th Dec 2015, 13:25
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Yes, you want the prop in the 2o'clock position rather than 12 or 4, both of which would be very awkward to swing. Prop can be bolted on in any of these positions.
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Old 14th Dec 2015, 14:02
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foxmoth Yes, you want the prop in the 2o'clock position rather than 12 or 4, both of which would be very awkward to swing. Prop can be bolted on in any of these positions
thanks, so was he verifying that the prop was correctly installed by moving it to its 2 o'clock position (for ease of propping) while listening for the impulse coupling click signifying that cylinder #1 was its firing position and feeling for the compression resistance. ( I assume the click only happens when cylinder 1 is at its firing stroke?
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Old 14th Dec 2015, 14:41
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I'm slightly confused by the "o'clock" recommendations.

foxmoth,
Are you talking about a Gypsy Major or its kin?

For a Lycoming or Continental, the prop needs to be in the 10 o'clock position (when facing the aircraft), as is indicated in the videos above.

mixed up,
It doesn't matter whether the fuel is on or off. There's enough fuel in the carburettor for the engine to start, if the mags are live.

flybymike,
I always kick my leg back when hand propping from the front. It gets me moving backward, away from the prop. However, I like to think I do it more elegantly than the guy in the Luscombe video! Of course, as has been said above, you need firm ground.

It is also a good idea to warn any non-aviation bystanders what you are going to do. A lady nearly fell out of her chair when I started a tow-plane at our club. She thought she was witnessing a fatal accident!

pb84,
If your Maule has an impulse mag, it's a good idea to turn off the non-impulse mag, to avoid a potential backfire (and finger tip issues). It has always surprised me that impulse mags are not identified on the mag switch.
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Old 14th Dec 2015, 15:59
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surprised me that impulse mags are not identified
In my hand propping days, many years ago, there was a "convention" that the left mag was the impulse. I never saw that written down but it seemed to work when applied to the various older types I was called upon to start - Chipmunk (not Shaggy's - the older one) SV-4C, various Jodels and Cubs and the really difficult VW powered homebuilts.

My only failure was a Pitts S1 flown by the now owner of Jet2 - I simply wasn't strong enough to get past a compression - he was not amused
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