Handpropping a Yak 52

[ahwalk01]

Handpropping a Yak 52? https://www.aviation24.be/miscellane...spital-france/

[DIBO]

re.https://www.aviation24.be/miscellane...spital-france/

Originally Posted by ahwalk01

handpropping a Yak 52?

or maybe it was more a case of: https://www.accidents.app/summaries/...20001212X18795

[ETOPS]

Doesn’t actually say that - let’s wait and see what the cause was…

[RichardJones]

Very sad indeed.

I've seen a PW R1340 attached to a Thrush Commander, hand propped. Needs to be cold, therefore loose and being a radial, things happen slow initially, so you have time to get clear. Being bolted to a conventional U/G A/C helps. More than can be said with reference to 4 cylinder, horizontally opposed engine for eg.

[hoppyasl]

Devastating news.

No details have been released as yet, but it is very unlikely that he was trying to hand swing the propeller to start the aircraft, More likely pulling through to remove any oil from the bottom 3 cylinders of the radial engine which is necessary before every flight.

There are various reason a M14P/PF could fire when pulling through...... magnetos left on, short in the magneto lead or hot spot on the piston head amongst the main ones.

As ETOPS states.... we have to wait for any findings to be released.

[Jhieminga]

Sad situation. Without knowing more about the circumstances it is not wise to speculate. But yes, some radials can be handpropped. Example here:

You Tube

[stevef]

Originally Posted by hoppyasl

More likely pulling through to remove any oil from the bottom 3 cylinders of the radial engine which is necessary before every flight.

Some amplification re hydraulic locks: Pulling through in the normal direction doesn't actually clear accumulated oil from the lower cylinders, it only serves to indicate an hydraulic lock. When resistance to rotation is found, removing spark plugs from the lower cylinders to allow the oil to drain is the only solution. Rotating the engine in the reverse direction only allows the oil to flow into the induction tubes; it then returns to the cylinder/s when the engine is started, an hydraulic lock is formed when the piston crown/s meet the incompressible oil and the conrod/s get bent. The seriously-wounded engine usually stops instantly. Even if it doesn't, it will eventually fail, probably at high power operation such as at take-off.

[EXDAC]

Originally Posted by hoppyasl

There are various reason a M14P/PF could fire when pulling through...... magnetos left on, short in the magneto lead or hot spot on the piston head amongst the main ones.

Normally a shorted p lead will inhibit a magneto. The "short" provides a ground path that is in parallel with the mag switch. It requires an "open circuit" p lead to enable a magneto when the mag switch is in the off position.

Is there something unusual about this engines magneto configuration?