Propellers are DANGEROUS
Joined: Sep 2003
Posts: 1,198
Likes: 0
From: South Norfolk, England
I think SNS3Guppy is generalising. He obviously knows his stuff, which is the point really! If you understand how engines work, (and yours in particular) then you can detour from the general recommendations fairly safely. However, you have to work on the basis of the lowest common denominator, and as such I'd say yes ... Do Not Touch or go near Propellers!
In the real world that's rubbish though!
I've stripped, rebuilt and constructed engines since I was a kid. I certainly don't know everything and more modern engine systems leave me cold. I do however, know my engine very well, prop it solo (no choice at my strip) and have propped many engines with confidence for many years. That said, I certainly wouldn't let my kids touch even my prop which is fairly safe as it's a Leburg. The reason is that I want them to be aware that props can kill, and if they get lulled into some false sense of security because Dad's engine can't start, they may think all aircraft are the same!
I think that's the point Stik was making right at the start of this thread ... innit?
SS
In the real world that's rubbish though!
I've stripped, rebuilt and constructed engines since I was a kid. I certainly don't know everything and more modern engine systems leave me cold. I do however, know my engine very well, prop it solo (no choice at my strip) and have propped many engines with confidence for many years. That said, I certainly wouldn't let my kids touch even my prop which is fairly safe as it's a Leburg. The reason is that I want them to be aware that props can kill, and if they get lulled into some false sense of security because Dad's engine can't start, they may think all aircraft are the same!
I think that's the point Stik was making right at the start of this thread ... innit?
SS
Joined: Oct 2005
Posts: 3,218
Likes: 2
From: USA
A small amount in an intake or even an aircleaner, could cause an engine to fire up, on a modest prop pull, even if spark sources had been disabled.
I think you meant something other than to say the spar sources have been disabled.
Disconnect the spark plug leads from the spark plugs...you've disabled the spark sources. You're not going to get a spark.
Joined: Dec 2011
Posts: 14
Likes: 0
From: Benfleet, Essex
Joined: Jan 2008
Posts: 1,191
Likes: 0
From: lancs.UK
Above post surely takes the record for resurrected threads, nevertheless, all pertinent and a timely reminder.
the report synopsis gave me a queasy stomach
One has to have sympathy for the poor trainee,watching his/her instructor do something so damned stupid,
complacency kills
Our banned colleague was pretty adamant about priming and accelerator-pumps.
some aircraft have a syringe-type primer so it squirts a neat slug of fuel into the induction tract. With a side-or down draught carburettor, Prime-fuel will invariably puddle in the inlet manifold Induction air will pass across it's surface and so become enrichened.....in a tail-dragger, it's likely to run towards the lower cylinders and trickle in when the inlet-valve opens...under those (flooding) circumstances, it is likely to wash oil off the cylinder-walls(simply replaced by the oil-scraper rings on the piston, next time it comes up the bore!)
So, pretty much a non-issue unless your starts are frequent and your runs brief,
Accelerator-pump.....not necessarily atomised, often a jet squirting into the venturi of the carb,and relies in the induction-air to atomise it and carry it into the cylinders.....again, dodgy on a stationary updraught carb, but a quick and effective prime on side and down-draught types.
KNOW YOUR ENGINE! English PPL syllabus requires a good comprehension of engine mechanicals and operation....build on that foundation and you can save a lot of heartache, wear and tear and cash..
An aside- Old Rolls Royce cars had both coil and magneto ignition.
It was possible to stop them with the ignition fully retarded.....return to vehicle, switch on ignition, set hand-throttle and mixture(quadrants on steering-wheel hub) then sweep the ignition A-R lever (also in the middle of the steering wheel !) towards the Advance and the engine would magically burst into life
A six, or eight-cylinder engine, which has been stopped by ignition-switch and NOT by fuel-cutoff, will invariably have one cylinder with mixture and piston in the correct position to ensure this happens.....
remember , in the case of an older aircraft with Magneto ignition, the impulse -startboth retards , AND gives a "quick flick" to the mag. for a strong starting spark.
I've hand-propped a number of times...simple and safe if you follow the rules!
the report synopsis gave me a queasy stomach
One has to have sympathy for the poor trainee,watching his/her instructor do something so damned stupid,
complacency kills
Our banned colleague was pretty adamant about priming and accelerator-pumps.
some aircraft have a syringe-type primer so it squirts a neat slug of fuel into the induction tract. With a side-or down draught carburettor, Prime-fuel will invariably puddle in the inlet manifold Induction air will pass across it's surface and so become enrichened.....in a tail-dragger, it's likely to run towards the lower cylinders and trickle in when the inlet-valve opens...under those (flooding) circumstances, it is likely to wash oil off the cylinder-walls(simply replaced by the oil-scraper rings on the piston, next time it comes up the bore!)
So, pretty much a non-issue unless your starts are frequent and your runs brief,
Accelerator-pump.....not necessarily atomised, often a jet squirting into the venturi of the carb,and relies in the induction-air to atomise it and carry it into the cylinders.....again, dodgy on a stationary updraught carb, but a quick and effective prime on side and down-draught types.
KNOW YOUR ENGINE! English PPL syllabus requires a good comprehension of engine mechanicals and operation....build on that foundation and you can save a lot of heartache, wear and tear and cash..
An aside- Old Rolls Royce cars had both coil and magneto ignition.
It was possible to stop them with the ignition fully retarded.....return to vehicle, switch on ignition, set hand-throttle and mixture(quadrants on steering-wheel hub) then sweep the ignition A-R lever (also in the middle of the steering wheel !) towards the Advance and the engine would magically burst into life
A six, or eight-cylinder engine, which has been stopped by ignition-switch and NOT by fuel-cutoff, will invariably have one cylinder with mixture and piston in the correct position to ensure this happens.....
remember , in the case of an older aircraft with Magneto ignition, the impulse -startboth retards , AND gives a "quick flick" to the mag. for a strong starting spark.
I've hand-propped a number of times...simple and safe if you follow the rules!
