On a serious note, I've only had to hand prop an engine a couple of times in my lifetime. Never did feel comfortable doing it. In the cold weather, I've spun the prop often when warming the oil, and never gave it a second thought. Had no idea that an engine could start with mags off. Guess I'll be a little more enthusiastic when spinning her from this point out in an effort to make certain all body parts are out of the way. Good advise one and all.
Larry [EMAIL PROTECTED] wrote: > John Cooper wrote: > > > > In a message dated 00-01-09 14:53:09 EST, you write: > > > > > Here's my first question: If you turn the prop "backwards" with the mag > > > switch 'on' and it hits compression on one cylinder and 'bounces' back > > > in the forward direction and slips out of your hands, (putting you > > > 'off-balance) couldn't this be dangerous since now the impulse couplings > > > on the mags would be active? Of course if the mag switch is 'off' then > > > > The impulse couplings are not much of an issue in this case. They don't come > > into play until about 25 degrees BTDC and fire at about TDC. If you don't > > move the prop in the correct direction, starting before they engage and > > folllowing through the lag angle (to roughly TDC) then they are not > > contributing. HOWEVER, it is possible to fire a plug without the impulse > > coupling, by turning the engine through the angle where the ignition points > > open IN EITHER DIRECTION. If you don't agree, take a plug lead in your hand > > and try it. > > > > > it would be okay as long as the grounding works properly. > > Many one handed pilots can attest to the fact that you should never rely on > > the grounded p-leads for anything. > > > > > Question #2: By turning the engine backwards, the oil pump is also > > > turning backwards and not pumping any oil into the engine. Wouldn't it > > > be better to leave the mag switch 'off' and turn the prop 'forward' for > > > a few blades and lube the cylinders before starting the engine? > > > > You would have to turn about 50 blades through to move a significant amount > > of oil. Some benefits are spreading what ever oil is already in the > > cylinders, a quick "Armstrong" compression test, and priming if you have a > > Stromberg and no primer, or if you have a primer and don't want to use it. > > (You're correct about radials. The bottom cylinder(s) can collect enough oil > > or fuel or both to bend a rod.) > > > > This reminds me of something I saw a couple of months ago. A couple of guys > > were getting ready to fly a Cessna 180. One slight old guy was "pulling the > > prop through". A 180 is a taildragger and the spinner is about 5 or 6 feet > > off the ground. This guy had his arms wrapped around the prop in such a way > > that if it fired, it would have cut him in half and flung the parts across > > the ramp. Should I have said anything? > > > > Lefty > > > > __________________________________________________________________________ ______ > > To unsubscribe from this list please send mail to [EMAIL PROTECTED] > > > > _____________________________________________________________ > > Keep up with breaking news! Join our Hot Topics list. > > http://www.topica.com/lists/breakingnews/t/12 > > Hi Lefty, > If I had been there I would definately have said something! I would > have 'humbled' myself so as to not come on like a "know-it-all", but I > think I could have made a suggestion without offending or belittling > him. And even if not, SO WHAT, I'd rather he'd get mad at me than to > kill himself. > If he was a pilot he would understand, and if he was not a pilot he'd > probably not know enough to argue the point. > Personnally, I learned the "leg-swing" technique over 50 years ago and > I still use it. Even if you should lose your balance and fall to the > ground, you'll be away from the prop. I've heard about every arguement > there is about using different methods on a 'small' and low compression > engine but I've started all types of singles and even some twins with > three bladed props and got them started and never even had a 'close > call' with a prop. It works for me so I'll keep on using it. > > Bob Saville > N3396H 415C > Eugene, OR > > __________________________________________________________________________ ______ > To unsubscribe from this list please send mail to [EMAIL PROTECTED] > > _____________________________________________________________ > Keep up with breaking news! Join our Hot Topics list. > http://www.topica.com/lists/breakingnews/t/12 __________________________________________________________________________ ______ To unsubscribe from this list please send mail to [EMAIL PROTECTED] _____________________________________________________________ Keep up with breaking news! Join our Hot Topics list. http://www.topica.com/lists/breakingnews/t/12
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