Propellers are DANGEROUS

[stiknruda]

Maybe I'm a little old fashioned. Maybe I'm a boring old nag.

During my basic training it was drummed into me that props are inherently dangerous. A prop that is momentarily rotated can flick over and it is not unheard of or even that rare for the engine to burst into life

You turn the mags off and the prop is only safe if both mags ground at the P lead.

Ergo - it is best to treat all props as "live and dangerous".

Over the past two or three weeks, I have seen people pull and push aircraft using the propeller blades as the lever.

Today I witnesed a whole family pose for the photographic reminder of their aerial baptism - fantastic, but no one warned them to avoid the propeller. Two wee boys were "hanging" off the blades and the photo was taken. It is statisically highly unlikely that the engine would have started, however as alluded to above, it is not uncommon.

Please, please, please - think about the inherent danger and brief your pax accordingly.


Boring old Hector/Stik

[eharding]

Indeed, which makes it all the more important on those occasions when you *do* have to pull the propellor through - those of us with radials in particular - to act in the same way as you would if you were trying to swing the prop for a start. High compression engines can brain you with a prop blade without any internal combustion being required - even in the complete absence of fuel, or HT leads being connected to spark plugs - luckily, on that occasion the blade missed my head by miles - did deliver a glancing blow to the b0llocks though. Not the sort of lesson you forget.

I was there when our mutual Uncle was pulling the prop through on his previous S2 which decided to fire a couple of cylinders - he might have short legs, but by God he can move fast when required....almost a blur, in fact.

[J.A.F.O.]

Just thinking about club types that I've hired in the past - C150s, C172s, PA28s - all the usual stuff. On most of the Cessnas the parking brakes don't really work yet most people just stand there, in front of the aircraft, pulling the prop round as part of their walkround. If it burst in to life what would stop it moving forward turning poor Johnny PPL into coleslaw on the way?

How should we do it? Well to one side, from behind, chocked with someone in the cabin? I don't mind it taking more time - always better to be five minutes late in this life than early in the next. So, how should it best be done?

[llanfairpg]

Always treat the prop as LIVE but in addition never get into or out of an aircraft with the engine running.

I was just about to start a SE aircraft one afternoon and when i say start I mean a millisecond away from turning the starter and someone popped up in front of me grabbed the prop and shouted. "I will just push you back a bit further"!

Thats why you always shout CLEAR PROP STARTING and I always did after that!

[DX Wombat]

pulling the prop round as part of their walkround.:eek:Who on earth teaches people to do that? I don't even touch the prop unless it has acquired a new dink and then only VERY gently to feel how rough it is and how far it seems to extend before getting it checked by someone better qualified.

[llanfairpg]

Its a must on DC3s first flight of the day!!! especially if you were up all night with Birch and Bramson

[SoundBarrier]

Hi Everyone,

A very dangerous thing these things are, I know of someone who prop swung a C402 successfully and only noticed that his watch had been removed by the prop when he was doing the runups! :eek: (watch was found smashed against the hangar wall!)

I have prop swung a few aeroplanes in my time, Piper J3, Cessna 182, Cessna 150 to name a few.

Some basic rules a few of which have already mentioned :-
1. ALWAYS treat props as LIVE (even ones hung at a bar! <-- face it if the prop falls off the wall and you fall off the bar as a result you could end up buying many a beer for many a month)
2. NEVER cycle the prop as part of your pre-flight
3. NEVER prop swing alone
4. NEVER trust just the parking brake, or the parking brake + toe brakes, ALWAYS use chocks
5. Children + Props - NO!
6. PAX + Props - NO!
7. You and Props - NO! (unless for the sole purpose of starting the aircraft)

Some aircraft have written procedures for prop swinging and if you're part of a club, the club will have it's rules to suit. Never just give it a go please, get someone competent to show you how it's done.

keep safe

sb

[fireflybob]

A point which is worth mentioning is that when you turn the mags off you are making a circuit by earthing the mag to the engine. This is not fail-safe in the event of malfunction of the "switch" (key etc) so this is another reason why props should always be treated as live.

In short you cannot assume the prop is not live just because the mags are off.

The problem with pilots pulling on the props to move the a/c is usually lack of an appropriate tow bar.

[Pilot DAR]

A long time ago, a pilot friend of mine, whom I would trust with my life, asked me to hand prop his flat battery Cessna 150. I was very comfortable hand propping, and happy to help him. It was an aircraft I also regularly flew, so I knew it to be in good mechanical condition, including the live mag check, which I had recently done…

As it was the first flight of the day, pulling it through a few times was appropriate. I called to him "Mags off" and he called back “Mags off”. I swung the prop once, it started, and ran quite nicely. I looked through the turning propeller at my friend in the pilot’s seat, and gave him that look, which he knew was my question to him, “are the mags really off?”. He immediately held up the keys, which I saw through the still turning prop!

This particular 150 was equipped with one of the mag switches which was later AD’d for internal failure which lead to two live mags. What a dangerous co-incidence that the time of the switch’s first failure, was the first time I would hand prop the plane!

If I have to touch a prop, I touch it assuming that the next thing it will be, is running!

Pilot DAR

[SNS3Guppy]

Always treat the prop as LIVE but in addition never get into or out of an aircraft with the engine running.


What's indicated here is a lack of understanding, and training regarding propellers.

You most certainly can safely manipulate the propeller by hand, and in some aircraft, it's absolutely necessary. From the responses thus far, one would easily assume that hand propping an airplane is no longer taught.

I grew up on airplanes without electrical systems, and handpropping was part of every engine start...no engine starter. I've handpropped airplanes over the years that do have starters when the occasion has arisn, and have always done it to teach students about proper propeller handling. Yes, it can be done safely, and yes, it can hurt you if you do it improperly.

Any radial engine pilot knows the necessity of pulling the propeller through by hand as part of the preflight.

As far as leaving the airplane with the propeller running, it's done in some arenas all the time. In ag work, for example, we frequently get out of the aircraft with the engine running. In the turbine airplanes, shutting down the engine and adding cycles is unwarrated and unwanted. In backcountry work, we'd sometimes get out, leave it on the left mag and chocked with a rock, and load our passengers and cargo. There are ways to do it safely and legitimately, but only with purpose and proper training.

Propellers can certainly be dangerous, but no pilot training is complete without being properly trained in the safe handling of the propeller. It is wholly inadequate and irresponsible for an instructor to merely teach a student to fear the prop.

[Tiger_mate]

At Liverpool many years ago a Cessna 337 passenger vacated engines running and walked away from the (front) prop, I am sure you can guess the rest.
http://ferryflights.aircraftdelivery.net/14.jpg
Photo to illustrate the point, not the actual aircraft

[A and C]

Thank you for adding some balance, the best post on this thread so far.

[BroomstickPilot]

I note that some of the new VLAs and three axis microlights, notably the Technam Sierra, are accessed over the leading edge of the wing. This is done using a foot rest below the leading edge.

These are very small aircraft and have only a short nose, so when climbing in or out, you are very close to that prop. Clearly, sooner or later someone is going to access or leave the aircraft while the engine is running.

I think this is an accident waiting to happen. Access should always be over the trailing edge.

Broomstick.

[IO540]

I teach my son to never even touch a prop, and explain the reason.

However, manipulating the prop is often necessary (to clear the towbar, to push the plane back, etc) and then I check the keys are out beforehand.

[172driver]

I note that some of the new VLAs and three axis microlights, notably the Technam Sierra, are accessed over the leading edge of the wing. This is done using a foot rest below the leading edge.


Same is true of the DA 40 :(

[wsmempson]

Also worth bearing in mind that if the propellor is attached to an enginge with a vacuum pump, very often that pump is designed to turn in ONLY one direction. The consequenses of inadvertantly turning the prop in the wrong direction can be a broken vacuum pump and loss of some of the instrumentation.

Whenever inspecting the prop during a pre-flight check, my old instructor used to say "never put more of your hand on the prop than you are prepared to lose...."

[DX Wombat]

Same is true of the DA 40http://img.photobucket.com/albums/v604/DX_Wombat/P1010120.jpg That step is also so high I need to use a caravan step as well. But it is quite a way back from the prop.

[Rod1]

Most VLA’s and probably the DA40 do not have old fashioned Mags or vac pumps. Standard operating procedure on a Rotax machine is to pull the prop through until the dry sump oil system “gurgles” normally about 30 – 40 compressions if the aircraft has not run for a while. If the solid state ignition is switched on it should still not fire as the system will not produce a spark below 300 rpm. I have to say I check the switches carefully, but I do move the aircraft by using the prop as it is the only practical way to do it.

Rod1

[llanfairpg]

What's indicated here is a lack of understanding, and training regarding propellers.

First of all Guppy this is not a forum for AG pilots but PRIVATE FLYING. I have seen a pilot flying inverted over an airfield at 100 feet but that doesnt meant its a practice that should be recomended to low hour amateurs.

If you treat the prop as live you are more cautious than if you see it as an implement to move the aircraft around the hangar. Of course you can swing a prop or move it but that is not what treating the prop as live means.

As for getting in and out of an aircraft with the engine running, why is it neccesary and when is neccesarry. Its a habit taught by lazy sloppy instructors who are possibly potential AG pilots.

[A and C]

This don't turn prop backwards because of the Vac pump is total and utter rubbish that is chured out by people who should know better and belongs in avations dustbin along with "don't lean the mixture below 5000ft".

The prop can be turned backwards by hand without damage to the vac pump, what you must not do is fit a Vac pump from an engine that turns to the right to a left hand turning engine (IE dont swap the vac pumps between engines on counter rotating twins).

If turning the engine backwards did as much damage as the mis-informed say we would all be changing them at the 150 hour check as checking the Mag timing requires the engine to be turned backwards to release the impulse coupling in the Mag(s).

[flyme273]

same problem with my Rallye, only practical way to ground handle is to push-pull the prop. Slats are too weak to push and no Cessna type struts. Tow-bar is only good for steering not push-pull.

For cold start, I turn the prop to reduce starter load. Should I do this?

if I understand the position correctly, even with the battery disconnected (e.g. for maintenance), the prop would still start?

[tacpot]

flyme237: Can you explain why the 'towbar' is not suitable for towing the aircraft? Could it be made more suitable via a modification?

For cold starts I'm not sure that turning the prop will reduce starter load appreciably, unless we're talking about a radial or inverted engine where hydraulic lock will overcome the starters efforts, and possibly damage the engine. It's probably not worth doing on a flat four/six cylinder engine.


On engines where magnetos provide the sole source of the spark, the battery is not part of the ignition system, so providing there is fuel in the supply to the engine, the engine would still run for long enough to do you a serious injury.

take care

tp

[Lister Noble]

I fly a hand start L4 Cub,and the only way to start is to swing the prop.
Chocks in place first.
First 6 blades pulled through to prime engine. with mags off .
Mag one on,swing to start.
Walk round and get in,run up and power checks etc.
Set engine to tick-over,get out and remove chocks,get back in and you are ready to fly.
No other way unless there are other bods about.

The big rule
Always treat prop as live.
Have massive respect for prop.
Walk forwards away from prop and out towards wing tip.
I am happier if others are around ,but that is not always the case.
Lister

[Zulu Alpha]

If the solid state ignition is switched on it should still not fire as the system will not produce a spark below 300 rpm.
This does sound a slightly dangerous piece of advice.
I am sure that electronic ignition will fire below this speed, probably with a retarded spark to assist starting.
I certainly know that mine does. And its doubly dangerous as electronic ignitions produce a much bigger spark than magnetos at very low rpm, hence even more chance of firing.
I have even had my electronic ignition 'kick' the prop when turning the ignition switch from off through, left, right to both. I put it down to the sensor being aligned with the magnet in the pickup. Switching it on and off in quick succesion replicated the engine turning and initiated a spark, hence the kick.
So even a completely stationary prop can kick.!

[flyme273]

tp

tow-bar on Rallye fits in the port side of the tyre spindle only, there is no corresponding starbd fitting e.g. unlike a Cessna. Provided there is no load it can be rotated to steer the nose-wheel. Any force and it keeps falling out. When one's-self is ground handling it can be quite a hand full, one hand holding the tow-bar the other pulling-pushing on the prop.

Cold starts, my intention is to pass over compression, then the starter has a half turn to spin up before being loaded. The 220 hp Franklin six has a significant compression and the starter will often not start to turn or labour heavily against initial compression.

Thanks for confirming battery information.

Have also used a Rotax, where rotation is required to clear sump oil. Would prefer a safer procedure.

Following this thread I shall take extra care. The Cessna 150 incident and loss of watch incident above really catches the attention - too close for comfort. Remember the one in USA where a Piper Cub owner was single-handed and was swinging the prop without anyone inside. It started flew itself for 5 miles and landed itself undamaged. The owner was lucky on two counts, firstly getting out of the way of the forward charging propeller and second to avoid a wreck.

[Windy Militant]

There is a reason to pull on the prop. Those of us who fly behind wooden propellers need to check that variations in temperature and humidity haven't caused the bolts to loosen.
The sage advice passed onto me by various venerable aviators, and it must be reasonably good advice as all of them still had a complete set of peripheral digits.
1) Chocks in, Brakes On or better still tied down.
2) Stay well clear of the prop arc unless you have a specific reason to be there: IE Inspecting it or starting it.
3) Never turn a prop unless you're actually starting the engine.
4) When inspecting the prop, check mags off, throttle shut, Mixture lean and fuel off.
5) If for any reason you do need to turn a prop, follow starting drill so if it does kick you can get clear.
5) Never stand in line with the plane of rotation just in case something lets go.

As for electronic ignition not sparking below 300 rpm I seem to remember an article in Popular flying where a Rotax engine started after having a water dispersant aerosol sprayed into it to inhibit it for storage. It didn't even have carburetters if memory serves, but it still ran for long enough to scare the daylights out of the poor bloke!

[Gertrude the Wombat]

Please, please, please - think about the inherent danger and brief your pax accordingly.
I always specifically tell my pax not to pose for photos near the prop. The universal reaction I get is "what do you think we are, stupid?" and I have a hard time persuading them that some people really do do this.

[SkyHawk-N]

I have a Horizon P-1000 digital tach., one of it's many useful features is it's ability to warn of a "hot-mag" situation. Consider one if you ever need a new tach.

[rosti]

And what about those of us who don't fly 50's technology and have modern dry sump engines like a Rotax with the dipstick in the tank? You have to turn the prop. to pump the oil into the reservoir to get a reading! There's electronic ignition, choke and of course a master switch so it's really quite safe...

[davidatter708]

Do you think it wrong then If your instrustor send you out to do a preflight and start up and they will join you when they hear you radio check or after 5 mins or so. Beacuise for 90% of my training my instrutor did exactly that and on first solo hopped out whilst engine was running.
David

[SNS3Guppy]

First of all Guppy this is not a forum for AG pilots but PRIVATE FLYING.


To start, I know this isn't a forum for ag pilots. You might benifit from experience that goes beyond your own, however. You seem to be offended by experience which may go beyond your own. You may not have ever flown an airplane such as a J-3 cub, for example, which lacks a starter. You may never have flown it by yourself to a location where there are no tie downs, or understand that you can't be in the cockpit during the starting process. You ma not know that one uses a piece of rope to tie down the tail, then handprops the engine and allows it to warm at a low power setting while untying the tail and entering the airplane...by yourself, with no one in the cockpit.

You may have never operated airplanes in cold settings or round engine airplanes (which private pilots fly, incidentally), where the aircraft is required to warm up for an extended period of time. Allowing the airplane to lope and warm up (generally with the oil cooler blocked by a cover) while attending to ground duties, especially if you're the only one there, is standard practice, and no, it's not lazy. A good practice, if one must get out of the aircraft with an engine running, is to chock the airplane or otherwise secure it.

Having flown frequent flights to remote areas to pick up persons or cargo, and having experienced airplanes that wouldn't start, I learned long ago that sometimes keeping the engine running is far more adviseable. In the case of some airplanes, it's necessary. On some older airplanes, standard practice has been to place the engine on the left magneto and let it lope while gaurding the propeller area and arranging cargo and passengers. This can be particularly true in a very cold environment. Perhaps you don't do it at your local flying club with lineboys, a hard surface runway, and all the support you need. You need not dismiss out of hand experienced input, however.

Yes, I'm an ATP, but I also hold private privileges and have a lot of years of flying privately, and instructing private pilots. No, I'm not a lazy instructor. I am an experienced one.

Don't make the assumption that an engine won't fire at low RPM. Residual energy in an ignitio coil may still cause a spark even if the magneto (or other ignition source) isn't properly grounded. Hot engines can fire by themselves, albeit rarely. An engine sitting with one cylinder at the top of the compression stroke can kick, and one should keep in mind that the propeller direction may also reverse, kicking forward or back. Merely getting smacked on the head by the propeller can do enough damage to seriously hurt (or even kill) you. If the propeller kicks back the other way (such as hand propping with your fingers curled around the propeller), it can toss you.

Last winter I was in Riyadh, doing some work on a Cheyenne. This has a turbine PT6 engine rather than a piston engine, which is why I'm still here to tell you about what happened. The airplane had an instrument problem, and I was working in front of the propeller, and moving back and forth past the propeller. It's a free turbine engine, meaning the propeller is driven by nothing more than exhaust gasses; nothing mechanical turns the propeller, from the engine gas generator. You can grab the propeller and move it all day long, no worries. I heard the turbine begin to wind up and saw a pilot had climbed into the cockpit and for some unearthly reason, elected to start an engine with two of us working in the prop arc. Fortunately for us, the turbine gives time to get out of the way, and initially, at least, the propeller moves very slowly.

I mention this to point out another way the prop can move; you might not be in the cockpit, but someone else could be, and they could move it.

I flew a large four engine radial powered bomber for several years. Standard entry was up the side of the airplane on a ladder built into the fuselage, right in front of the #2 propeller. The prop had a 12' arc, and was large. I always felt a strong sense of caution when climbing into the airplane in front of that turning propeller. Yes, there are certainly times when working around the propeller when it's turning is necessary and proper, but care must be taken. When working on a piston engine (I'm also an aircraft mechanic), sometimes one is required to stand directly behind the prop while inspecting for leaks, etc

When turning a propeller by hand, many myths exist. Some basic rules of thumb should be followed.

Your vacum pump, if engine driven, is either a wet pump or a dry pump. If you have a dry pump, chances are it's a carbon vane pump, which are notoriously weak. The pump is designed to turn in one direction because that's how it pumps air (or draws air, depending on it's useage as a vacum pump or air pump for boots)...not because it will shatter and fail if the engine is pulled backward. The carbon vanes internally slide in and out of a shaft in which they are loosely mounted. They do this in order to form a loose seal with the chamber walls of the pump, internally. In order for them to slide more easily, they are angled in their mounting to enable function...turning them backward doesn't cause them to break, as the vanes are free to slide in and out of the slots in which they ride. If you already have debris in the pump (it's i the process of failing), or it's cold and there's condensation and ice in the pump then turning it backward can cause a vane to break...but turning it forward will do the same thing, and after that breakage will continue by virtue of the broken vane parts alone.

Most common damage to carbon vane pumps is caused by the use of teflon tape on the inlet and outlet fittings, or use of pipe thread compound...which enters the pump. It's also caused by those replacing the pump, but not the filters and not thoroughly cleaning the system by blowing it out. Vacum pumps fail regularly, and should never be counted on past about 500-600 hours. I've seen them fail in 5-10 hours in service. Owners or mechanics cleaning engines who allow moisture or solvents into the pump are also responsible for premature failures.

As for counsel regarding never turning a propeller unless you're starting it, the advices too broad. After shutdown, a wooden propeller, for example, should be placed parallel to the ground. This is done to prevent imbalance and moisture buildup in the lower blade...a concern with the wooden propeller. Metal propellers should often be placed like this too, to prevent passing aircraft from striking a blade that might be sticking up. Three bladed props should be placed in the Y position, with two blades up, to reduce the vertical distance extended upward by the propeller for the same reasons...to reduce the chances of a passing aircraft encurring a wingtip strike. This also has the added benifit of avoiding tripping people who might strike their legs when the blades stick down by the knee caps. You'd be surprised how often this happens. In some cases turning the prop so a blade points down (metal props only) to allow the spinner to drain is appropriate.

Turning a propeller by hand may be done as part of the preflight for several reasons, including listening to the engine, as well as clearing potential hydraulic lock (radial engines). It may be turned through when finding the impulse coupling to hand prop, or simply to place a blade in the proper position for hand propping, or finding the top of a compression stroke. It may also be moved to place the blade in a position for starting if one must start and has a weak battery...giving the engine the greatest chance to fire. Many reasons to move the propeller when not actually starting or using the starter are valid. You should never do so, however, without having been properly trained, being fully alert, and leaving yourself an escape.

Many years ago when I was a teenager, I was working at the airport on a Sunday afternoon. A local private pilot entered the building, looking like he'd been in a gang fight. His clothes were shredded, he was cut and bruised and beaten up, and had blood all over his body. I asked him how he was. He said he was surprisingly well, and that he had just been struck by his own airplane. He had incorrectly set the throttle at half before hand propping, hadn't chocked, and tied down (inexplicably) the left wing only. The engine fired, the airplane ran over him, and was destroyed when it made an arc to the left and struck a nearby fuel truck (puncturing the truck in the process).

Hand propping and handling the propeller is safe if done responsibly. It's potentially very painful if not.

As for pulling or pushing on the propeller; one is best advised not to do so, but if you must push near the engine, you're better off doing do on the propeller as close to the shank (hub) as possible, rather than on the cowl. Use caution, obviously, and don't reach through the prop arc to push on the cowl or other parts of the airplane if at all it can be helped.

If you are going to move the propeller, don't wrap your fingers around it. Place your palm on the blade back (the part facing the front of the airplane...the blace face is what you see from the cockpit). If pulling the propeller through in the direction of rotation (typically clockwise as seen from the cockpit, but varies depending on what and where you fly), you can use your fingers slightly but they should be kept mostly straight and not curled around the propeller. Don't stand far enough away you have to lean toward the prop; your center of gravity will take you into the propeller if you slip. Don't stand so close it strikes you.

My preferred method when pulling a prop through is to stand about 1/2 to 2/3 radius (two thirds of the way out from the hub, on the blade), or a little farther. I use flat hands on the prop, and will put my right leg forward into the prop arc (prop not moving). When I pull downward, I ensure I don't bend at the waist, and at the same time I swing my leg to the rear keepng my back straight. As I do, I step backward, so that the momentum of that backward kick carries my body away from the propeller. (should go without saying that you ensure nobody else is behind you first, and that your starting area is clear). If the propeller fires, I'm already moving away from the propeller and to one side...to my right, and I can continue to take steps backward should the airplane move. (Remember, it's chocked, tied, and if a parking brake is available, brakes set). If the propeller doesn't fire, then I move up and start again.

As far as pulling the propeller through to "limber up" the engine as some instructors teach, you're not really accomplishing much. You're not going to be circulating oil (especially in cold weather), and any residual oil on the cylinder walls and bearing surfaces is going to be disturbed so that the engine experiences higher wear on startup. No need for that. Preheat the engine thoroughly; this will do more for protecting the engine on startup during cold weather than any perceived benifits of pulling the prop through. Remember that vacum pump with condensation inside, too...pulling it through in either direction can result in broken vanes.

Yes, there are many reasons when one might turn the propeller by hand, from a preflight inspection of the propeller and spinner to listening to the engine to verifying or alleviating hydraulic lock to finding the compression stroke, to setting the engine on the impulse coupling, and many more...but it must be done by someone who is trained, alert, and acting responsibly. Respect your propeller. Don't fear it. Get educated.

I'd like to touch on the notion of priming your engine by pulling it through. Don't do that. All you're going to do, assuming you do get fuel into the cylinders, is wash the lubrication from the cylinder walls, and you're putting yourself in a potentially bad situation. You wouln't want to handprop with more than the throttle open just a bit, and you wouldn't want to fill the cylinders with fuel before moving the propeller by hand, either. You have the equivilent of a wide open throttle then...the engine won't run that way for an extended time, but it only needs to wind up for a brief moment to seriously hurt or kill you. If you must pull the prop through when the engine has been flooded (and there are times when this may be necessary), do it against the direction of rotation, being careful not to grasp the blades or curl your fingers around them, and keep clear. Treat the engine as though it will fire each time you move it.

If you're doing like some and trying to "prime" using your accelerator pump (pumping the throttle)...don't do that. You're not accomplishing a thing other than posing a fire hazard. No matter what your instructor told you. I see this as a very common mistake, often made by the instructors themselves. It's okay to question what your instructor has taught; chances are that he or she was taught by another low time pilot, who was taught by another low time pilot, and you have there a heritage of inexperience and a litany of bad habits, each one doing it and not knowing why. Always look for better understanding and a better, safer way.

[davidatter708]

Guppy I follow my checklist and guess what it says pump the throttle

[stevef]

A and C & Guppy are right about the vacuum pumps. It doesn't matter at all which way you turn the engine by hand; you're not going to damage them. I have a letter from the Parker Hannefin (vacuum pump manufacturers) Service Department confirming this.

[stiknruda]

My "rant" was based at those who should know better, allowing the untrained/uneducated to handle their props - not the rest of us who regularly hand-swing, check for hydraulic loss or do a quick compression check assessment as we pull through.


It really was aimed at protecting the "innocent".

[eharding]

But an interesting exchange in any event.

In terms of pax briefing, my recurring nightmare is someone wandering off and walking into the prop of one of those Rotax machines you can hardly hear, especially if there is something else thundering away in the vicinity.

[Flying Binghi]

Beautifully written Guppy.

How true it is ..."a heritage of inexperience and a litany of bad habits, each one doing it and not knowing why."

[SNS3Guppy]

Guppy I follow my checklist and guess what it says pump the throttle


Perhaps you might be a little more specific as to the aircraft, checklist source, type of carburetion (surely you're not pumping the throttle in an injected engine), and if you have an updraft carburetor.

I've seen a lot of poorly written checklists that have incorrect information, or lack in presentation.

Do you understand what the accelerator pump is, how it works, and it's limitations?

Am I not understanding your penultimate paragraph? I hand-start my little Continental A-65. Are you saying that, following priming using the pump, I should not suck in?


If penultimate means the last paragraph, then it specifically referred to use of the accelerator pump. If you're referring to the second to last paragraph, I did discuss pulling the engine through after priming. Some feel this is an appropriate cold weather soloution, though it does remove lubrication on cylinder walls, increases the possibility of a stack or intake fire, and in the case of hand propping, can dramatically increase the impulse and RPM rise when the engine does fire.

If you're hand propping an airplane that has no other way to start, then yes, you may need to prime. You may, like some, prefer to start on the prime, then advance throttle. I always advocate caution in doing so, and discourage people who flood out the engine and then pull it into or through the engine by moving the prop. Depending on your priming system, you may not be pulling much in.

[BackPacker]

In terms of pax briefing, my recurring nightmare is someone wandering off and walking into the prop of one of those Rotax machines you can hardly hear, especially if there is something else thundering away in the vicinity.

My flight instructor told me this, and I always tell my passengers: "If you can't see the prop, it doesn't mean that the aircraft is U/S. It means it is turning."

[aviate1138]

Quote:
In terms of pax briefing, my recurring nightmare is someone wandering off and walking into the prop of one of those Rotax machines you can hardly hear, especially if there is something else thundering away in the vicinity.

From a Rotax 9 series engineering blog.


Warning! Never turn the prop backward
on a 9-series engine. Doing so will cause
the oil pump to work in reverse—draw-
ing oil out of the engine and filling the
oil passageways and hydraulic lifters
with air.

[Xoxon]

Guppy - thanks very much for taking the time to explaining that and giving me (and doubtless a few other people) the benefit of your experience. I really appreciate it.

[IFollowRailways]

Guppy,

Great posting, except I can't agree with -

If you're doing like some and trying to "prime" using your accelerator pump (pumping the throttle)...don't do that. You're not accomplishing a thing other than posing a fire hazard.

From the actual SOCATA approved Flight Manual for a 1978 Rallye 180 (MS.893E) with a Lycoming 0-360 A1A (so not fuel injected)

Edition 10, Page 4.07. Section 4.4.1. Starting the engine -
Normal procedure
Mixture - full rich.
Main switch - On
Alarm panel - Energised ........ etc
Propellor - fine pitch.
Fuel level - checked
Fuel cock - Open, light off.
Booster pump - On
Injection - Pump throttle 2 to 3 times.
Throttle - push forward 2cm
Surroundings - Clear.
Starter - Operate, 30 sec. Max. And so on!

The language in the manual is slightly quaint in places due to the translation from the original french, but injection in this sense undoubtably means that you should prime the engine by using the accelerator pump. On this particular aircraft there are no other means of priming other than pumping the throttle.

[Rod1]

All the DR400’s I have flown did not have an American stile primer. All used the throttle to prime.

Rod1

[SNS3Guppy]

The throttle does not prime. It's an air valve.

On carbureted engines using an accelerator pump, a fine mist of fuel is sprayed into the induction when pushing in the throttle lever. The purpose of this mist, called an accelerator pump, is to prevent the engine from stumbling during throttle increase by enrichening the mixture. It is not a primer.

[Mikehotel152]

:uhoh: I shall never go near the prop again, except to check the blades for nicks and inside the cowling for loose pipes, birds' nests etc.

I so often see people pulling the aircraft about using their props that I started doing it. I have seen the error of my ways. :(

[blue up]

Hand propping with Leburg ignition is easy and safe. Zero chance of kicking back. Ignition is 100% dead with the battery switches off.

Video of first engine runs after 3 year restoration....

http://s82.photobucket.com/albums/j279/foggythomas/?action=view&current=2005_1011Image0022.flv

Rope tied around wheel rims as a quick-release handbrake plus this one is rawlbolted through the tailskid to the concrete driveway.

I still have all of my fingers. I always keep a tight hold os some immovable part of the fuselage to ensure I don't fall into the prop. Watch the hands!

If anyone wishes to comment/ridicule/besmirch my technique then I'd be happy to accept any good advice so that we might all learn the safe method os 'swinging'.

[SNS3Guppy]

Blue Up,

That was a beautiful example of proper (no pun intended) handling, and hand-starting the airplane.

I'd love to see more pictures of the airplane itself. Looks like those three years of effort paid off!

[Jodelman]

"It is not a primer."
That's not what the POH for the Robin DR400/160 says.

[Sir George Cayley]

Firstly, in this thread and others about hand swinging props i've read , if you are working solo, then one vital action I don't recall reading about is just before Mags On

FUEL OFF :ok:

It might seem a strange thing to do, but if you have ever been unfortunate to witness an light a/c set orf on full chat with the pilot desperately chasing it you will understand.

Secondly, Blue Up. G8 vid and a smashing example of good engineering and aviation best practice. But, bit of a Gay pose after:p Sorry cudn't resist.
;)

Sir George

[Tony Mabelis]

All instrument panels on Tiger Club aircraft at Redhill were placarded....

'ALL AIRCRAFT BITE FOOLS'

Which is as true today as it was years ago!!

In my nearly 50 years working on aircraft, I have seen the aftermath of turning props, a guy at Hawker aircraft Co. with half a face and an arm missing,(Sea Fury) an engineer friend of mine who nearly broke his hand a couple times when the engine kicked back,(Gipsy Majors) an aircraft started and ran away, in the hangar at full power, after a pilot decided to see what the compression was like on this particular engine.(Volkswagen)

I have had 12 stitches in my shoulder from the wind driven Generator on an Auster, and several scars from model aeroplane engines.........so that makes me??
Yes I admit it!!
But I have learned the lessons, I am still around to tell the tale, but it scares me to watch the disrespectful way people treat props. these days.

Propellers are not for:-
1. Radial engine pilots, to show off to the crowd at an airshow how manly you are.
2. Turning while the engine is red hot, after shut down, 'cos it looks neater horizontal'
3. Pulling and pushing the aircraft in an out of the hangar.
4. Something you let your kids mess with while you stand and watch.

[Rod1]

"It is not a primer."
That's not what the POH for the Robin DR400/160 says.

Agreed

Rod1

[SNS3Guppy]

What does the engine manufacturer have to say about it?

Carb manufacturer?

[blue up]

Teaching the next generation since the RAF no longer allow Cadets to touch dangerous aeroplanes...
http://s82.photobucket.com/albums/j279/foggythomas/?action=view&current=2300bb.jpg

Worlds' oldest aircraft carrier....
http://s82.photobucket.com/albums/j279/foggythomas/?action=view&current=moggi2.jpg

Hand propping for cowards (me in the yellow) video clip...
http://s82.photobucket.com/albums/j279/foggythomas/?action=view&current=FredEngineRunFFF06.flv

Doing the school run...
http://s82.photobucket.com/albums/j279/foggythomas/?action=view&current=goingforaweighing.jpg

[SNS3Guppy]

Very nice, blue up. Is that a volkswagen or revmaster vw motor?

[onetrack]

Re Windy Militants post .. WD-40 makes an excellent starting assist fluid, along with ether .. and along with most stuff that comes in aerosol cans ..

WD-40 is regularly used by the tractor crowd, for their worn-out old diesels, because it doesn't produce the high explosive, engine-damaging, knock, that ether in a can, does .. but it still cranks them into life, just as effectively .. :ooh:

[SNS3Guppy]

Re Windy Militants post .. WD-40 makes an excellent starting assist fluid, along with ether .. and along with most stuff that comes in aerosol cans ..

WD-40 is regularly used by the tractor crowd, for their worn-out old diesels, because it doesn't produce the high explosive, engine-damaging, knock, that ether in a can, does .. but it still cranks them into life, just as effectively ..


I sincerely hope you're kidding.

[onetrack]

I am most certainly not kidding. What I stated is the truth. Why, the great concern?
All aerosols contain highly flammable ingredients, and WD-40 makes an excellent start-assist fluid for compression ignition engines, due to its lower volatility as compared to ether, and its lubricant/water dispersant additives.

[SNS3Guppy]

First, you should be running with an airfilter for your induction. The air filter should be positively secured to the induction such that it can't come loose or block the induction in any way. This prevents access to the induction for spraying "starting fluid."

Second, the most effective application of a starting fluid is during the starting process, not before. This puts you in a position of applying the material in the close presence of a moving propeller.

Third, most light airplane systems are updraft, unlike priming your car or tractor in which pouring fuel or spraying fluid down the induction puts the flammables downstream of the carb.

Fourth, so-called priming with the acceleration pump, or fogging the induction with "starting fluid" creates a fire hazard, particularly with a backfire by placing a volatile mixture near the front of the induction. Condensation of that mist, drips, runs, etc, can pool either in the induction or beneath it and create a fire which can be difficult to fight or put out.

Fifth, WD-40 isn't starting fluid, nor should it be used as such. Why not just pick up any number of flammable chemicals and spray it in your aircraft induction every time you want to start the engine? Why not just learn to use it properly when "starting fluid" isn't necessary.

Sixth, show me what engine manuacturer, or aircraft manufacturer recommends the use of "starting fluid" to do an engine start.

Learn to start the engine properly and it won't be an issue for you.

[blue up]

SNS3. Homebuilt version of the VW, Stromberg auto carb mounted above and behind the crankcase, Leburg ignition with variable timing that fires at 3 degrees AFTER TDC below 600rpm to almost guarantee that the engine will never ever stop in flight due to slow running and to ensure no kick-back during starts. Buzzers tell you when the ignition system is live or when they are on low battery. Generator is a 15 amp Honda motorbike alt mounted where the flywheel used to go. Dual ignition with separate batteries that are independent. Fuel on, choke out, pump on, throttle set, ignitions off, 8 blades, fuel off (so it can never fly off alone!), throttle set, ignitions on, pull past TDC, started! It starts even easier now that the engine is run in.
I've not got a parking brake so I tie a slipknot that can be released from the cockpit after it has been looped through the spokes of the wheels and behind the seat. If the plane rolls forwards then the rope gets taught as it coils round the wheels and stops them rolling any further. Lightest parking brake in the world (green rope in the first video). Cheaper than chocks and can be safely removed once the pilot is strapped in.
We had to use starter fluid on the Webster Whirlwind engine to get it to fire. Not sure why that was other than the fact that the whole engine was home-made from bits of VW, bits of DAF and a home-made crankcase and crankshaft. (handpropping for cowards vide above)

[Windy Militant]

Sixth, show me what engine manuacturer, or aircraft manufacturer recommends the use of "starting fluid" to do an engine start.


I believe it was called Ki Gas priming!

And if you're concerned about fuel in the induction system never ever read the bit about cold weather starting for Gypsy Major engines. It involves holding the tail up so that when you tickle the carb you get a more even level of fuel in the inlet manifold! :ok:

[onetrack]

SNS3Guppy - My post's intention was not a recommendation for WD-40 for starting fluid for aircraft engines .. nor was it a recommendation that any starting fluid be used at all, except maybe in a rare and extreme situation.

My post was a warning that any aerosol used carelessly around an aircraft engine can create an ignition hazard .. as in someone spraying WD-40 around, to dry out or lubricate something. 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.

[shortstripper]

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

[SNS3Guppy]

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.


No spark, no fire.

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.

[-Alan-]

Air Accident report on G-BHPK

Air Accidents Investigation: Piper J3C-65 Cub, G-BHPK (http://www.aaib.gov.uk/publications/bulletins/october_2012/piper_j3c_65_cub__g_bhpk.cfm)

[cockney steve]

Above post surely takes the record for resurrected threads, nevertheless, all pertinent and a timely reminder.
the report synopsis gave me a queasy stomach :yuk:

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 :8

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!