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
