Stranded - AOG

mtuomi said:
I agree with that. But being surprised its not taught, and saying he wouldn't sign a student for the practical test without that seems insane to me.
Definitely something that to me is more in the "can you teach me this" category, rather than "you have to learn this to be a pilot".
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I really think that propping up is something that should be taught. Even if you never intend to use it, you will learn something useful.
 
Henning said:
I really think that propping up is something that should be taught. Even if you never intend to use it, you will learn something useful.
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And retain it for how long?

I was great at had propping my cub, now I'm good to go to prop the Beaver :yikes:
 
Tom-D said:
having some one walk into to a prop is a lot different than messing yourself up.
Here ya go sonny, this is your new sports car. that's the gas pedal. push it down to go fast. see ya, have a nice day.
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That's 5 seconds, in 5 minutes I can deliver all the information required for someone to safely prop up a plane, I was taught in less.
 
Henning said:
That's 5 seconds, in 5 minutes I can deliver all the information required for someone to safely prop up a plane, I was taught in less.
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no wonder we have so many hurt trying it.
 
Tom-D said:
The deco generator on the 0-300, is a 35 Amp, that is a pretty easy charge rate, but it will be the generator that will fail in flight, at 35 amps the battery will not be close to fully charged in the time allowed by your routine. and the voltage regulator will be charging the battery at a full charge rate of 35 amps. until the battery is above 13.2 volts.
If his 172 has a 50-0-50 gauge the needle will show the 35 amps, If his 172 has the 30-0-30 it will show a full deflection.
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I took all that into account with the advice in my post about how to run it after starting.

The gen, even at full rated power will not charge the battery at full rate until it reaches 13.2 volts. The charge of the battery isn't determined exclusively by the regulator, but by the internal resistance of the battery, and the voltage of the combined cell voltage presented to the charge field(also the type of regulation, whether it's full or half wave rectified). It will charge at full rate on an almost dead battery for a short time as the voltage rises quickly along with the internal resistance.

The regulator provides clipping to the charging voltage, because that's what regulators do, they regulate(you may see this on your ammeter as a very suble wavering of the needle under load). I also advised that he should stop and investigate if it charges full rate for more than a short time, lets get specific and say 45 seconds.

The drive for the generator was designed to account for a full 35 amp load, plus a significant torque budget increase. If it fails in flight - oh well, it wasn't up to specs to begin with. I have the same coupler on my Conti engine, driven the same way, and I have a 50 amp alternator, replacing a 50 amp generator. If it breaks, then it was not up to par either. Too bad so sad. Normal generator use will not damage the drive coupling, even if it runs at 35 amps forever, and ever, and ever as long as the gen is getting some blast air.

And I'm done here. OP, do what you want, ignore everything I wrote, I have lost interest in helping. YMMV, don't try this at home, and objects in mirror are larger that they appear.
 
I'd like to put this out there. Just because you deliver information, doesn't mean someone is listening, understanding, or retaining. 5 minutes to teach proper hand propping? Maybe. Making sure they retain it? Generally, not in 5 minutes. You need to make sure they understand why a competent person needs to be at the controls (a cub was damaged near Zanesville, Ohio, because the guy set the throttle too far in woth no one at the controls, and the plane decide it wasn't going to wait on him anymore, it wanted to go FLY), the dangers behind hand propping, and the proper motions and why, and make sure they are doing those motions. What about understanding how a magneto works and impulse couplings? Wouldn't it suck if a guy was positioning a prop and the mag fired and kicked the blade? Not all blades stop at the 10 and 4 positions to make it easy for propping. It's not just our job to hand people information on a platter, but make sure they can understand it enough to think about the implications as they do it. That takes a little more than 5 minutes.
 
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mtuomi said:
I agree with that. But being surprised its not taught, and saying he wouldn't sign a student for the practical test without that seems insane to me.
Definitely something that to me is more in the "can you teach me this" category, rather than "you have to learn this to be a pilot".
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Dozens of instructors around more than willing to teach you to the PTS and nothing else. Let them take your money; I won't unless you agree to learn what I have to teach.

I train pilots, not airplane guiders. And my fee is for time spent with the prop turning. You get the prop-pull lesson for free.

Now what's your beef, sonny?

Oh, and by the way, when MY airplane comes up for annual, I expect ALL my current students (and former, if they feel like it) to show up to do the grunt work. Payback is a *****, ain't it?

Jim
 
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Tom-D said:
I'm telling ya there is no venting done in the early 170/172 battery box other than to keep the inside pressure the same as the out side. There is no tube supplying air to the battery box, there is only 1 drain at the bottom of the box. which in many cases I see the plastic tube is turned brittle, broken and the acid has etched the fire wall from that point down to the fuselage skin.
And yes, the battery acid does get all over the belly when it is boiled out at a high rate charge.
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I back up Tom on this. It IS a drain, that tube. The shape of the bottom of the battery box implies it, and in any case Cessna calls it that. And it does drain out acid and sprinkle it on the belly, where it eats the paint off and starts on the aluminum.

And the chief cause of that is overfilling the battery. If one reads the manufacturer's instructions, he will see that the cells are filled to the split ring while the battery is actively charging. Filling it to the split ring at any other time will only result in it overflowing into the box (once the alternator or generator go to work) and out that drain. The electrolyte expands while charging because of the gas bubbles forming on the plates.

I will top up the cells while it's in the airplane, but only to the halfway point between the top of the plates and the bottom of the split ring. It will expand and rise to the split ring. When people top it to the rings the acid boils over, and topping it up again with water results in diluted acid, which, of course, is the same as reduced specific gravity, which weakens the battery's output. Do that enough times and you are buying a new battery and wondering why the old one only lasted a year or two.

Venting of the battery box is done via a non-gasketed lid and around the cable openings. Lots of air leaks in and out. If the drain tube is the right length, airflow will suck plenty of air through the box.
 
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I know a C-180G has a vent (drain) tube out the bottom of the batt box through the fuselage.

And if you run a maintainer, run it on 2 amps or else you'll get a nice white stain etched into your concrete where that tube comes out... :mad2:

I watched a hand prop demo at OSH this year and learned a few things. Treat every prop like it's a loaded gun for one thing. And don't kick your leg when you prop like in the old movies....
 
txflyer said:
I know a C-180G has a vent (drain) tube out the bottom of the batt box through the fuselage.
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That battery is located in the rear fuselage not on the firewall, like the early 172, and yes it has a vent.
 
Tom-D said:
That battery is located in the rear fuselage not on the firewall, like the early 172, and yes it has a vent.
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Yep, I haven't moved mine to the firewall like some do. The wagon is forward C.G. enough ...
 
Tom-D said:
no wonder we have so many hurt trying it.
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The guy who taught me was over 80 and learned on an OX-5, hasn't been killed, I haven't been killed or injured at it either. If you believe it is that difficult, I suggest you not do it.
 
txflyer said:
I watched a hand prop demo at OSH this year and learned a few things. Treat every prop like it's a loaded gun for one thing. And don't kick your leg when you prop like in the old movies....
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I would actually like to know more about this. Never hand propped a plane. Nervous about turning or touching them otherwise. I do have to rotate them when they are in the way of the towbar's path and that click scares me every time. When disconnecting the bonding cable I always do it from the side, never through the arc for anything.

When can the prop fire on a standard small plane? Is turning the prop backwards bad for the engine and will it prevent the engine from jumping to life? Are there times when the master is off that it could go? I know how to jump in and stop an engine if it happens but the mechanics escape me.
 
If it is magneto driven with an impulse coupling, it will only fire in forward rotation. Be cautious with those planes, because the ignition stops the sparks by routing the spark to ground when key or switches are off. If the p-lead or the ignition switches are faulty, a spark will occur in the cylinder when the impulse coupling clicks.

Electronic ignition (fully electronic or CDI) depends on design, but in general they won't fire if you rotate slowly (as in, not trying to hand prop).

Some engines don't like backwards rotation, like Rotax. A little is fine, but it stretches the spring on the starter sprag clutch if you are cranking it backwards. You can also introduce air into the oil system, which rotax engines are not very fond of (specifically the hydraulic tappets can sieze under the right conditions)

There are other things that i am probably not mentioning. Read your poh or ask someone if you don't fully understand your fuel and ignition system.
 
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Henning said:
The guy who taught me was over 80 and learned on an OX-5, hasn't been killed, I haven't been killed or injured at it either. If you believe it is that difficult, I suggest you not do it.
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I was hand propping aircraft before you were potty trained.
 
Anticept said:
If it is magneto driven with an impulse coupling, it will only fire in forward rotation. Be cautious with those planes, because the ignition stops the sparks by routing the spark to ground when key or switches are off. If the p-lead or the ignition switches are faulty, a spark will occur in the cylinder when the impulse coupling clicks.

Electronic ignition (fully electronic or CDI) depends on design, but in general they won't fire if you rotate slowly (as in, not trying to hand prop).

Some engines don't like backwards rotation, like Rotax. A little is fine, but it stretches the spring on the starter sprag clutch if you are cranking it backwards. You can also introduce air into the oil system, which rotax engines are not very fond of (specifically the hydraulic tappets can sieze under the right conditions)

There are other things that i am probably not mentioning. Read your poh or ask someone if you don't fully understand your fuel and ignition system.
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I remember when we checked the oil level on a Rotax, we used to turn the prop until you can hear it "gargle".
Took a while when it is -25C...
 
docmirror said:
I took all that into account with the advice in my post about how to run it after starting.

The gen, even at full rated power will not charge the battery at full rate until it reaches 13.2 volts. The charge of the battery isn't determined exclusively by the regulator, but by the internal resistance of the battery, and the voltage of the combined cell voltage presented to the charge field(also the type of regulation, whether it's full or half wave rectified). It will charge at full rate on an almost dead battery for a short time as the voltage rises quickly along with the internal resistance.

The regulator provides clipping to the charging voltage, because that's what regulators do, they regulate(you may see this on your ammeter as a very suble wavering of the needle under load). I also advised that he should stop and investigate if it charges full rate for more than a short time, lets get specific and say 45 seconds.

The drive for the generator was designed to account for a full 35 amp load, plus a significant torque budget increase. If it fails in flight - oh well, it wasn't up to specs to begin with. I have the same coupler on my Conti engine, driven the same way, and I have a 50 amp alternator, replacing a 50 amp generator. If it breaks, then it was not up to par either. Too bad so sad. Normal generator use will not damage the drive coupling, even if it runs at 35 amps forever, and ever, and ever as long as the gen is getting some blast air.

And I'm done here. OP, do what you want, ignore everything I wrote, I have lost interest in helping. YMMV, don't try this at home, and objects in mirror are larger that they appear.
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^^^ What he says.

Is it the best way to charge a battery? No, not really.
Is it going to make your airplane into a bomb? No
Is it going to kill your alternator/generator? No...if putting out it's full rated output for a bit of time were to kill it..it was already on its way out..

I'd be hesitant to do it on some airplanes, like ones with electronic ignition. But I sure the hell wouldn't be afraid to do it on a 172, especially if I were planning on trashing the battery anyhow which is often exactly what I'm planning on doing since it let me down in the first place.
 
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I can see that complete and proper instruction for hand propping an aircraft can be done in 300 seconds.

Walk up the the plane. Explain how and why to turn it in the proper direction, considering wind direction and ground slope. Explain the setting of switches, throttle, mixture. Discuss throttle position and primer usage (if applicable) considering ambient temperature and other conditions. Review the theory of operation of a four stroke engine and explain the proper procedure for determining the engine is at the beginning of a compression stroke and that the propeller is advantageously positioned for a hand pull. Emphasize the importance of safety and review the method in which the magneto fires so the student can expect a successful pull. Demonstrate the proper position to stand and grasp the propeller, and further explain the motion necessary to generate sufficient force for the pull. Explain the importance of pulling through and moving the limbs and body away from the propeller arc. Discuss the movement to the cockpit to adjust the engine controls so the engine keeps running. Demonstrate the safe removal of the chocks. Review the method of entry into the cockpit.

Now that this is all done, perform a live demonstration from beginning to end. In the interest of safety, repeat this and then go through a brief review.

Next it's the student's turn. Have him demonstrate the procedure from beginning to end. To ensure he has completely understood your instructions, a repeat should be performed. Once this has been done, go through a verbal quiz session to determine the student's mastery of the procedure.

Now, having instructed the student in this simple procedure and having seen him perform exactly two hand prop starts in the allotted five minute period, shake his hand and send him on his way.
 
So I went through this stuff in my head, and assuming that we didn't actually go in and set up the aircraft, or played with anything in the cockpit, or had to move or chock it (basically, walk up to plane, lecture, spin prop), it came out to a little over 5 minutes for a barebones lesson, and leaving them with the warning that the process will vary with other aircraft. There's no way you're going to do this safely in 5 minutes walking them through everything you want to do if you are going to make any part of it a LIVE exercise. Finally, this assumes the student gets it perfectly and already understands some of the systems at work.

Now, how much are they going to retain? You should ask them a week later.

I still disagree that 5 minutes is enough time to really make sure someone understands what is going on, and not just making the motions. It's enough to cover the basic stuff, but it's not enough to make sure they UNDERSTAND what's going on, so that if they miss a step, or forget something, they don't tire themselves out, or worse, forget that the throttle is left in and the plane decides it's a strong bird that don't need no pilot.

Lecturing isn't teaching. Just give them a book for that.
 
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So is the OP issue fixed yet?
 
overdrive148 said:
I would actually like to know more about this. Never hand propped a plane. Nervous about turning or touching them otherwise. I do have to rotate them when they are in the way of the towbar's path and that click scares me every time. When disconnecting the bonding cable I always do it from the side, never through the arc for anything.

When can the prop fire on a standard small plane? Is turning the prop backwards bad for the engine and will it prevent the engine from jumping to life? Are there times when the master is off that it could go? I know how to jump in and stop an engine if it happens but the mechanics escape me.
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Anticept pretty much covered it. The impulse coupler on most of the magneto boxer type engines creates a spring wound spark each time it clicks, but that spark is killed by grounding through the p-leads and switch.

Just treat every prop like it's going to fire if you turn it and you'll be covered. I never turn mine backwards although the debate about it is questionable as to whether it hurts or not, so I just don't do it.

Stand flat footed facing the prop with a good stance so you don't lose your footing. You put most props at the ten-oclock position, and just put your fingers over the trailing edge of the prop to the first digit on your fingers. Don't grip the prop. Pull down and as your pulling down step back and keep stepping back.
 
txflyer said:
The impulse coupler on most of the magneto boxer type engines creates a spring wound spark each time it clicks, but that spark is killed by grounding through the p-leads and mag switch when the switch is in the OFF position for both mags.

I was taught that a boxer engine (so named by Hitler) had both pistons on one side coming up together and then both pistons on the other side coming up together. As I vaguely remember it, it makes the design of an "interference free" engine easier. I've never seen an aircraft engine like that.

I never turn mine backwards although the debate about it is questionable as to whether it hurts or not

I've never heard that debate about Continentals, Lycomings, Franklins, or other standard airworthiness certificated aircraft engines.

Jim
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.....
 
Henning said:
Have you been mutilated and/or killed doing it? How long did it take you to learn to do safely?
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Propping a 1340 on the Nordy, I was hurt pretty bad. I take hand propping pretty seriously, and do not advise any doing it to an aircraft not set up for it. And for those who must get more than 5 minutes of training.
 
tmyers said:
Is that a comment about your age or how long it took to potty train Henning?

Sent from my HTC6525LVW using Tapatalk
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You assume that he is.
 
jesse said:
.if putting out it's full rated output for a bit of time were to kill it..it was already on its way out..
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You do realize how old most of these old generators are? Cessna quit using them as OEM in the early 60s. Most have never had the bearings replaced. many no longer have the cold air scat tube installed.

Yep, go push your luck,, WE need the work.
 
weirdjim said:
.....
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Horizontally opposed engines are boxer type, which includes our very familiar lineup of aviation engines.

The "turning the engine backwards" applies to Rotax (they do have certified certificated editions of their engines, see 912s!). As for the other engines, I've never seen the manufacturer of the engine say you can't turn it backwards, but the real question is, what about the accessories? That might be where the issue is. I have no idea, just throwing something out :)
 
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Anticept said:
Horizontally opposed engines are boxer type.

The "turning the engine backwards" applies to Rotax (they do have certified editions of their engines, see 912s!). As for the other engines, I've never seen the manufacturer of the engine say you can't turn it backwards, but the real question is, what about the accessories? That might be where the issue is. I have no idea, just throwing something out :)
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Remember the reference can be written, revised, and updated by non professionals.
That term is not often used in discribing an aircraft engine, simply because of the letters in the type of engine "0" is the preferred term. TSIO. IO. R, I, etc.

ever see a "B" for Boxer given as the type?
 
Tom-D said:
You do realize how old most of these old generators are? Cessna quit using them as OEM in the early 60s. Most have never had the bearings replaced. many no longer have the cold air scat tube installed.

Yep, go push your luck,, WE need the work.
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Well, considering how I've never seen one killed by this, I must be incredibly lucky.

If a generator/alternator on an airplane of mine were killed by outputting it's rated power then once again it was already junk and I'm glad to get it fixed.
 
Tom-D said:
Remember the reference can be written, revised, and updated by non professionals.
That term is not often used in discribing an aircraft engine, simply because of the letters in the type of engine "0" is the preferred term. TSIO. IO. R, I, etc.

ever see a "B" for Boxer given as the type?
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The sources, however, are not edited just by anyone, and while there's a dead link or two, most lead to some decent reads.

While we don't call them Boxer, they are still from that lineage and go under the "boxer" umbrella.
 
Anticept said:
While we don't call them Boxer, they are still from that lineage and go under the "boxer" umbrella.
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Do you know how the Continental corporation chose the name of the engine they would produce?

Look it up, it may amuse you.
 
Tom-D said:
Propping a 1340 on the Nordy, I was hurt pretty bad. I take hand propping pretty seriously, and do not advise any doing it to an aircraft not set up for it. And for those who must get more than 5 minutes of training.
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What did you not know that got you hurt?
 
Tom-D said:
Do you know how the Continental corporation chose the name of the engine they would produce?

Look it up, it may amuse you.
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My Google Fu is weak, but I'm still looking.
 
Tom-D said:
You do realize how old most of these old generators are? Cessna quit using them as OEM in the early 60s. Most have never had the bearings replaced. many no longer have the cold air scat tube installed.

Yep, go push your luck,, WE need the work.
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Easy test, on airframe. Reach around behind the generator. The center shaft is exposed. Try to wiggle it. If you feel the LEAST amount of wiggle, the bearing needs replacing.

Jim
 
Anticept said:
Horizontally opposed engines are boxer type, which includes our very familiar lineup of aviation engines.

Read further into your reference for "true boxer". I stand by my original statement.

The "turning the engine backwards" applies to Rotax (they do have certified editions of their engines, see 912s!). As for the other engines, I've never seen the manufacturer of the engine say you can't turn it backwards, but the real question is, what about the accessories? That might be where the issue is. I have no idea, just throwing something out :)

I didn't say certified (and I would have used the term "certificated" if I had) engine, I said normal (as opposed to experimental) category AIRCRAFT.

If I were you, I throw that idea out too. WAY out.
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.....
 
The Atlantic at Austin considered it safer for them if I prop started a Malibu on their ramp than install a new starter. It was a three blade so I had to flip the prop up from the pilots side. The P46-310P has impulses the 350p has the shower of sparks system and normally props starts easily but you need electrical power. I've prop started so many airplanes but I'm a little worried about a 4 blade. Maybe I'm just getting too old.

I still remember the last word from the counter help at Atlantic when I told them that I was giving up and prop starting the airplane "okay have a nice day"
 
The reason to not turn an engine (with accessories) backwards is that it may break the vacuum pump vanes, particularly the carbon ones.
 
nrpetersen said:
The reason to not turn an engine (with accessories) backwards is that it may break the vacuum pump vanes, particularly the carbon ones.
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Yeah, that's disputed. I believe there is a small component to truth in it, however in order for it to occur, the vanes were very close to end of life already.
 
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