Hand propping class

[cgoldy]

I thought I should teach myself how to hand prop my O375. (8.5 to 1 compression ratio with left hand mag being impulse) All worked well. After stopping by leaning, she consistently starts on the left mag only on the 4th blade after being primed with one pump on the throttle. Without priming it starts on blade 5.

Am I risking back fire by priming with the throttle?

Also I know you are supposed to start with a flat palm on the back of the blade. But no way can I get enough grip without a little bit of finger over trailing edge. To the first knuckle. I felt better with a leather glove on. Is this because of the size of the engine or is this pretty normal for all planes?

Any comments?

Cgoldy

[Henny]

Here's a thread that started with a question I asked about pulling the prop through, but that also has some good replies about priming and using the throttle during starts.

http://www.supercub.org/forum/showth...t=pulling+prop

I always put a leather glove on if I have to hand prop and also find I have to curl the fingers over a bit to get a good grip (160HP O320)

[cubdriver2]

Since almost everything now has a impulse on one or both mags grip the prop with your fingers over the top of the blade, a kick back rarely happens when starting on a impulse mag. With an impulse you don't have to get the prop moving fast enough for the mag to fire so just pulling it thru will make it fire, so don't do the ole leg swing when propping. Get a good footing and just pull the prop with a follow thru that gets your hands out of the way. I like propping things, I used to prop everything Rhinebeck had up to a 400 hp V12 Liberty. Footing and follow thru and remember that your in charge if someones sitting at the controls because nothings going to happen to them if something goes wrong. When I worked at Rhinebeck the pilot never said mags hot or mags off the guy pulling the prop called those out and the pilot would say " that's what it say's " to remind you that it's always hot.

Glenn

[Dave Calkins]

Stand behind on the right side. With your left hand, hold onto the back edge of the right cowl door. Wear a glove on your right (prop swinging) hand if you are more comfortable.

Before you begin, know how sharp the trailing edges of your blades are....some could hurt an ungloved hand.

You'll learn pretty quick what your engine likes for prime and throttle position, whether cold or after a run.

...lots of satisfaction in knowing your engine and knowing it will start on "this" blade.

[5 Rivers]

So..............how you gonna hand prop Jon Bush's exp cub?????

[Dave Calkins]

So..............how you gonna hand prop Jon Bush's exp cub?????

..you think that's an original question Randy?

[5 Rivers]

Just couldn't resist................

[L18C-95]

Any suggestions for standard operating procedures for hand swinging in a club training environment for a no electrics cub (C90-8F)? One suggestion has been to have both instructor and student in the aircraft, and either another club member or maintenance hand swing the prop, but what about landings away from the club field?

[Snert]

Any suggestions for standard operating procedures for hand swinging in a club training environment for a no electrics cub (C90-8F)? One suggestion has been to have both instructor and student in the aircraft, and either another club member or maintenance hand swing the prop, but what about landings away from the club field?

Glider tow hook.
N969DJ_009.jpg

[C-90 Cub]

Since almost everything now has a impulse on one or both mags grip the prop with your fingers over the top of the blade, a kick back rarely happens when starting on a impulse mag. With an impulse you don't have to get the prop moving fast enough for the mag to fire so just pulling it thru will make it fire, so don't do the ole leg swing when propping. Get a good footing and just pull the prop with a follow thru that gets your hands out of the way. I like propping things, I used to prop everything Rhinebeck had up to a 400 hp V12 Liberty. Footing and follow thru and remember that your in charge if someones sitting at the controls because nothings going to happen to them if something goes wrong. When I worked at Rhinebeck the pilot never said mags hot or mags off the guy pulling the prop called those out and the pilot would say " that's what it say's " to remind you that it's always hot.

Glenn

How many people here have been caught off guard by getting a hot prop and having the engine start unexpectedly? All it takes is one time and you'll never forget it. I cringe everyting I see someone pulling a prop thru priming it and before the blade stops they have their hand in the prop arc pulling on it again just because the switch is off. I don't think there is anything more dangerous than a prop that has stopped out of position just before the impulse coupling is about to snap. Just the slightest pull and it can start. When this happens ALWAYS call for switch off.........no exceptions. Even with the switch off I pull the prop backwards to propping position so that the impulse doesn't click.

People get complacent propping airplanes over the years because they are so reliable. Like Glenn said you HAVE to treat a prop like it is going to fire everytime you pull on it. Also, use common sense. If you are propping an airplane by yourself somewhere, take an extra minute to at least position the aircraft so it will not be aimed at anyone or anything if possible. Aim it in a direction that will do the least damage to other people or property just in case it does somehow get away from you.

That's my 2 cents anyway,

Steve

[aktango58]

been a few situations on the small airport in Haines with airplanes getting away. One was a very cold day, the pilot went out and was turning the prop on a 206 to break oil loose, and it fired, went to full rpm, took off, crashed in the trees and exploded. The intended passengers were told not to load and wait in the van until he had gotten the plane warm... saved their lives.

The other was a plane warming up on the ramp, guy drinking coffee in his truck, and the emergency brake came off... it idled into another's tail.

I had to had prop my champ. It would not start unless I had about 1" of throttle in, no matter what. If I was just going to stop quick, I would do the seaplane trick of killing with mags so she started easy, (I know, but kill me for using tricks that save lives in currents). I was moving folks to a small strip from town one day and put a guy in the back seat, set the throttle, and told him when she fires, pull back...

can you see where this is going????

I was able to hold the strut enough to get her turned in a generally safe direction and scramble over the wheel to where I could reach into the cabin... but for 5 seconds it was scary.

Moral of the stories: TIE IT DOWN!!!! The glider hook is a great idea, or just tie it down, start it, then untie after you have idled it down. Never go forward of the struts after you un tie!

If a club is going to had prop, teach them to TIE IT EVERY TIME. If you use the back seat pilot, what will the low time pilots do when taking friends? they will depend on the back seat person to save them...

[jgerard]

When standing behind the prop like you do with a cub I think it's important to bend at the knees when pulling the prop down like doing a squat and instead of trying to throw the prop like you would a spear by just using your shoulder. Pull it down like you are trying to do a pull up bending your arm at the elbow. Know how far you need to move it before the mag fires and make sure you pull it down in a forceful and deliberate motion to that point. Pull that prop with confidence and respect. Don't be in a hurry, avoid distractions, verbally say your check list out loud as you go through the motions, and if it does not start in 5-6 blades then STOP. Determine if it's lean or flooded and take the appropriate actions. Again when clearing a flooded engine avoid distractions and verbally say your checklist as you do each step. It's best after clearing a flooded engine to leave the mixture out, pull the throttle back to idle then crack it, and don't prime at all. Once the engine starts then you push in the mixture and turn on the right mag (assuming its a left impulse only) If you can't safely move fast enough to push the mixture back in then you should get help. After clearing a flooded engine expect it to start on the fist blade. Every time you move a prop expect the engine to start.

Jason

[12Geezer2]

ANY DOUBTS---A good piece of rope around the tailwheel and a sturdy post---good cheap insurance--my 2 cents

[Amorl]

I can't remember where, but I saw a video with some guy handpropping his plane from behind. He had a loop from the cockpit to hang onto, and when handpropped, that loop made him able to pull himself back from the propeller in one, simple movement. He had tyres, but I think it would work well on floats as well. In fact, it looked like it was taken from the "float community".

[Mauleguy]

When I had my cub, O-360 with 10.5:1 compression, every start was a hand prop (no electrical). After 150 hours of doing it, I had it down pretty good. Hot starts and really cold mornings cub still be a pain sometimes. I never tied the tail down and relied on the parking brake, would check it before trying to prop by trying to push the airplane.
On soft surfaces I did not use the brake after I got use to propping, pretty hard to push even a light cub on 35" with 3 psi of pressure.

Then one day I took this guy for a ride in my airplane, he was a pilot also. He climbs in the back seat and I begin my routine for propping when he asks me about tying the tail down. I tell him I don't need to tie the tail down that the airplane will barely roll up hill with 3 guys pushing on it, that it is safe to start this way. I tell him I have probably started the airplane like this 300 times by now, including wide open throttle hot starts. We are sitting on his grass strip pointed uphill and I double check throttle position and mags on. I pull it threw and on the third blade it fires but unlike normal it goes to what feels like 1800 rpm as I am scrabbling to get in and pull the throttle back, he is smiling when I look back at him. I am sure he pushed it forward to teach me a lesson and I am not sure whether I got it pulled back to idle or he did but I am positive it was not the position I left it in when I looked at it last.

Did he teach me a lesson, yes I guess, because after that I treated every start like it was a wide open throttle hot start. I still did not tie the tail down or set the brakes in most cases.

I was up flying that airplane in Alaska this winter (Hank was kind enough to loan it to me for a week) and it was on big straight skis, that is even more of a challenge because as soon as it would fire it was moving. The brand new carbonfiber skis had shinny smooth bottoms and all the gates to get from the ski strip to the hanger at Merrill Field are motion activated which means you have to get close enough to them but not run into them. The taxi ways are ice so you slide like crazy, I think I had to kill the engine and restart 3 or 4 times to get from ski strip to hangar. By the time I made it to the hangar I was worn out. If I had my airplane on skis I am pretty sure I would not be at that airport hangared, what a pain in the ass.

[cubdriver2]

Be sure of your footing, if it's slick move the plane or improve your footing



Glenn

[mvivion]

Be sure of your footing, if it's slick move the plane or improve your footing



Glenn

That right there is a classic example of why you should ensure proper indexing of the prop to ensure ease and safety of hand propping, AND the reason I almost ALWAYS prop from behind, where there's lots of stuff to hang onto, and the opposite direction the airplane is going to go when it does start. This is a recipe for disaster, in my opinion.

Opinion,

MTV

[sierra bravo]

I hand prop with the engine primed, throttle set as necessary, and last thing Before propping I pull the mixture to lean cutoff. Once the engine starts I have a few seconds to reach in and enrich the mixture. If something prevents me from doing so the engine quits before an unattended throttle can become a problem. This technique requires pulling the prop from the aft side. It's how the best Cub pilots I know do it so it's how I've done it.

[ag-pilot]

Mike that looks like a 5 cylinder radial of some kind,,,Doubt you could index that prop so it would always come up on compression horizontal,,, I hand prop R-985 quite a bit and with a low wing spray plane there in no other way than from the front but unlike flat engines they come to life fairly slow and give you way more time even more so cold. I always leave the tail tied down until I have it all warmed up though.

When I hot prop a lyc. cub I usually give it one shot of throttle, mix rich and throttle cracked 1/8 or so left hand in the upper door frame opening swing the prop with the right. 3-4 blades will have her running. Cold down to 40 or so 3 full jabs of throttle every thing else the same and it will start in 3-4 blades. I only prime if its been outside in less than 20f overnight with no preheat. to easy to frost the plugs with the primer IMHO. Never had a Lyc not start this way that had good mags and plugs and never had one on fire.. Can't say the same for the big injected Continentals though,,,

Dave

[cubdriver2]

That right there is a classic example of why you should ensure proper indexing of the prop to ensure ease and safety of hand propping, AND the reason I almost ALWAYS prop from behind, where there's lots of stuff to hang onto, and the opposite direction the airplane is going to go when it does start. This is a recipe for disaster, in my opinion.

Opinion,

MTV

Mike it's a Kinner R-56, 540ci the pistons are as big as oatmeal boxes, but only 5.5 to 1 compression. The 7 oclock position is the best spot. It does not take alot of muscle or movement to prop, just pull the prop past TDC and if primed right it fires right off at idle. I'd pay good money to see you prop this from behind

Glenn

[bob turner]

I teach hand-propping. You have to use the first knuckle, but there is never a need to use the second. I haVe no idea where that "swing the leg" idea came from, but I have a couple of students who think it looks cool.

The Schweitzer glider hook goes on a Maule tail wheel easily, and allows release from the cockpit with just a string. But for single pilot operation, the Cub starts safely from behind. I installed a Schweitzer when folks started propping from in front with no safety pilot. We almost lost a Cub from that unsafe procedure.

I had a guy march up to my prop one day, holler "stick back, brakes set, fuel on, throttle idle, contact" and then proceeded to give my beautiful wood prop a beefy shove. It took good reaction time to release the brakes before that shove became an irresistible impulse.

I teach two words - "contact" and "switchoff". I teach a "hysteresis" technique so the switch is never "on" unless the guy in front knows it is. I teach no leg swing - and always step back after pulling, assuming it will start no matter the position of the switch.

So far, so good. I average 365 starts a year, and September will be fifty years.

[mvivion]

Mike it's a Kinner R-56, 540ci the pistons are as big as oatmeal boxes, but only 5.5 to 1 compression. The 7 oclock position is the best spot. It does not take alot of muscle or movement to prop, just pull the prop past TDC and if primed right it fires right off at idle. I'd pay good money to see you prop this from behind

Glenn

Glenn,

Actually, I have propped Kinners from behind....on an old style Montana snow plane.... There had to be an adult at the controls, so guess who got to prop the beast? We had one with a Kinner and one with a Ranger Menasco inline six. To be honest, I don't recall how those pusher props were indexed, though. Those engines started easily in very cold temps, with no pre heat.....they hadn't seen an overhaul in a loooooonnggg time, and were loose as a goose. I've also propped R 985s....from behind.

I don't know how or if you could re-index that prop, but standing on glare ice, in front of a meat cleaver is not a great idea, no matter how it starts.

Again, opinion.

This has been a perpetual issue with the Huskys. They all come from the factory with the props indexed at 12/6, which makes them downright nasty to hand prop (and yes, I've done it on more than one occasion, and from behind, on wheels, floats and skis). After a bit of that, I decided to push for re-indexing, which it turns out is legal, based on the original TC data. It is a HUGE pain in the keester, however, to pull one of those Hartzell compact props off and re-install it. Nevertheless, doing that at the same time that we swapped out the OEM POS battery with an Odyssey, and I never HAD to hand prop one again.

My point is, if you can, make certain your prop is indexed to 10 and 4 (viewed from the front) for ease of hand propping, and I am an advocate of almost always hand propping from the back.

MTV

[cubdriver2]

On a Fleet or OTW 10 is too high an leaves you standing on your tip toes even at 6' with 5cyl you get a variety pack of positions but 9 and 7 work the best for me

Glenn

[C-90 Cub]

I don't throw a leg on a small or low mounted engine when propping. But something like a Stearman where the bottom blade is actually coming out and down because of the angle of aircraft stance I do. It gets the body going in the right direction to get away from it especially being stretched out to reach the prop. Again, small engines I prop from rear, but I am not as comfortable propping the bigger, Stearmans, Twin Beeches, Wilgas, Yaks, etc) from the rear for whatever reason.


Had an incident at Appelton going to Oshkosh one year. Guy in a 182 had shut it off for whatever reason on the taxiway and had things all screwed up because it wouldn't start and planes were arriving in masses. By the time I ran up to him they already had the battery out.........no idea what he was planing on doing with it. I told him to get in and I would prop it for him. He looked at me and said, "Buddy it won't run, the battery is out of it!" So then I said let my buddy have control the airplane and we'll get you to a tiedown. I made sure the battery cables were secured and the plane started first pull. The guy had no idea an airplane would run without a battery! That's when I learned to have someone that is qualified in the drivers seat when hand propping. Everyone doesn't know this stuff and we take for granted they do because it's something we do all the time.


Had a deal with a Wilga that wouldn't start too. Air system had bled out so I offered to prop it. He said I couldn't because it turns backwards I busted out laughing and said, "How about I just stand on the other side!!!" It also started right up. Make sure you have someone you trust inside the airplane..........most spam can drivers don't have a clue, so be careful offering to help.

Hardest airplane I ever propped was a Glasair III with an IO-540 in it. Lot's of compression and very low to the ground. It sucked.

Steve

[CRANMAN]

As long as everyone is getting their two cents in I will also. I learned to hand prop my duster friend's 450 Stearman many years ago. He taught me to pull nine blades on a cold engine(mags off). Then left mag on, crack throttle, use both hands with one knuckle curl, and a leg kick to get body moving away from the prop. We tied it down unless he himself was in the cockpit. A leg kick is not necessary nor advisable on a small lyc. or continental.

[hatz215]

Agree on leg swinging on higher powered engines. I propped an O-320 Hatz for 25 years. That last split second of the swing, your hands are moving down and to the right at the same time you're taking that step away and to the back and right. You're always moving away at the release point.
Don't always do it with the small Continentals though.

Steve

[sierra bravo]

Guys with Cubs should familiarize themselves with how to hand start their planes while alone in the middle of nowhere with nothing to tie to. In such situations it's better to know how than to learn how.

[kevin]

Mike it's a Kinner R-56, 540ci the pistons are as big as oatmeal boxes, but only 5.5 to 1 compression. The 7 oclock position is the best spot. It does not take alot of muscle or movement to prop, just pull the prop past TDC and if primed right it fires right off at idle. I'd pay good money to see you prop this from behind

Glenn

.


I have a friend of mine who had a Meyers OTW-160. The propellor was indexed at the 7 position too. They would walk the propellor thru when starting. When it fired, they would be in front of the left wings. There was never, ever an issue.

[Hardtailjohn]

Kinners are easy to start...if you know a Kinner. If you try to swing them too hard, you just get tired. I've started them countless times when someone else had exhausted themselves, trying to swing it too fast. They like a nice slow pull, just like Kevin says.."walk the propellor thru"...
The horse power rating has less to do with hand propping than most think. The important factors are prop length and compression ratio. Lower compression is very easy to prop. The worst I ever did was a homebuilt with a Volkswagen in it. That little bitty prop and the high compression was a nasty combo!

[12Geezer2]

C-90 Cub is right. Some airplane drivers really don't know much about their machinery. Happened by a Bonanza driver late one Sunday who was stressed out. He really had a case of get home itis and had left his master and who knows what else on. Dead battery. Was at a total loss as what to do. He had no clue about propping. The scarry part was a pilot who didn't know much was at the controls but I risked it and got him fired up and on his way.

[ag-pilot]

As long as you have enough battery to run the boost pump the big Continentals will hand prop I just hate the 2 cylinders that come up at 12-6 or there abouts. One thing you do want is a fire extinguisher handy cause if it backfires at all and quits it will be on fire and without a battery to start it and suck the fire in your screwed...don't ask me how I know this!

Dave

[C-90 Cub]

One thing you do want is a fire extinguisher handy cause if it backfires at all and quits it will be on fire and without a battery to start it and suck the fire in your screwed...don't ask me how I know this!

Dave

LMAO!!! Ok.........I'm going to be polite and not ask. Good info to have.

[cubdriver2]

When I was propping the Gnome rotary it liked to be real juicy, the crankshaft is the motor mount and the engine spins, nine cyl with a single 3" valve in the top center of the head that was both a intake and exhaust valve at different times. The crank is hollow and the pilot turns the fuel on and you spin the prop and engine nine times till fuel is " running " out of all the cyl as they pass the bottom, the engine is fed fuel like a 2 stroke thru the hollow crank to the crankcase and up thru a one way valve in the top of the pistons. The Sopwith Camel has round cowl around the engine so by the time you get it primed the inside of the cowl has a lot of gas dripping everywhere, if it misfires and doesn't catch it's a race against the fire to get it to start again. Fun stuff.

Glenn

http://youtu.be/sY07FI91F9M


http://youtu.be/MZM1kc_N770 no throttle, selector switch let you run it on 3 cyl, 6 cyl or wide open, blip switch kills ignition as long as you hold it down, rpm can't excede 1275 or centifical force tears it apart and you have to control two levers that control fuel and air that is always changing as you go up and down or it quits and fly the airplane and look for the enemy and fight for your life.

[ron]

More weetabix in the morning ocker!

[cburg]

37 Pilot, but never hand propped. I just bought a pusher aircraft with a upgraded Continental 65. (weight and Transponder is the reason for a hand propped aircraft).

I'll start from the front near the throttle.

First knuckle (finger tips?) and no thumb wrap?

I have one impulse mag…should I install a second? I know I start only with the impulse mag, to avoid kick-back. I have a little training from the previous owner.

I teach hand-propping. You have to use the first knuckle, but there is never a need to use the second. I have no idea where that "swing the leg" idea came from, but I have a couple of students who think it looks cool.

The Schweitzer glider hook goes on a Maule tail wheel easily, and allows release from the cockpit with just a string. But for single pilot operation, the Cub starts safely from behind. I installed a Schweitzer when folks started propping from in front with no safety pilot. We almost lost a Cub from that unsafe procedure.

I had a guy march up to my prop one day, holler "stick back, brakes set, fuel on, throttle idle, contact" and then proceeded to give my beautiful wood prop a beefy shove. It took good reaction time to release the brakes before that shove became an irresistible impulse.

I teach two words - "contact" and "switchoff". I teach a "hysteresis" technique so the switch is never "on" unless the guy in front knows it is. I teach no leg swing - and always step back after pulling, assuming it will start no matter the position of the switch.

So far, so good. I average 365 starts a year, and September will be fifty years.

[cubdriver2]

Everybody does it a little different, with an impulse I have always had my finger tips over the edge. Don't do the big leg swing thing, get a good footing and with an impulse mag all you have to do is move it past it's firing point with a follow thru that gets your hand and arm out of the way. I start a 1931 Curtiss Jr pusher but do it from the back. Don't forget and walk into the prop, most props are out front so think real hard anytime your behind the wing.

Glenn

[cburg]

Glenn, thanks for the advice. I’m a little concerned about hot-starts and flooding. I saw it flood once during my pre-buy and could tell it would be easy to get tired and frustrated…and much less carful.

My situation will typically involve cold-starting (should not be a problem) at my hanger, taxiing to the pumps, shut-down and warm re-start. The owner never did these warm-starts, or hot starts, so I need to experiment on a procedure (indeed a ritual).

I want to avoid hauling (and mixing) gas…I do that now for my Rotax trike and Rotax gyro…what a pain! I want to fill-up at the pump.

Chuck

Everybody does it a little different, with an impulse I have always had my finger tips over the edge. Don't do the big leg swing thing, get a good footing and with an impulse mag all you have to do is move it past it's firing point with a follow thru that gets your hand and arm out of the way. I start a 1931 Curtiss Jr pusher but do it from the back. Don't forget and walk into the prop, most props are out front so think real hard anytime your behind the wing.

Glenn

[cubdriver2]

Chuck if you have a Stromberg carb and you start it warm/hot don't prime it, and you have to open the throttle about an 1/8" to get it past the idle circuit or it will suck fuel and flood when warm. Tie it, chock it, and check the throttle position a couple times before you flip it.

Glenn

[cburg]

OK Thanks, it makes sense. That will really help.

Chuck if you have a Stromberg carb and you start it warm/hot don't prime it, and you have to open the throttle about an 1/8" to get it past the idle circuit or it will suck fuel and flood when warm. Tie it, chock it, and check the throttle position a couple times before you flip it.

Glenn

[Cub Builder]

Chuck if you have a Stromberg carb and you start it warm/hot don't prime it, and you have to open the throttle about an 1/8" to get it past the idle circuit or it will suck fuel and flood when warm. Tie it, chock it, and check the throttle position a couple times before you flip it.

Glenn

Or turn the engine backwards 4 or 5 blades to clear the engine before you prop it. It will light off at idle in 1 or 2 blades.

CubBuilder