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Hand Propping a Gasser

Old 01-06-2015, 03:30 AM
  #101  
sensei
 
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Originally Posted by BarracudaHockey
I've perfected placing the tips of my fingers against the face of the prop and flipping 50, 60, and 120cc gassers. That way if there is a kick back I don't get smacked
This is good advice and exactly what I do up to the 200cc stuff and beyond. Respect that business end but don't be frightened by it because that in itself will cause you to get hurt, fear causes anxiousness and in turn errors at the wrong moment!

Bob

Last edited by sensei; 01-06-2015 at 03:47 AM.
Old 01-06-2015, 04:45 AM
  #102  
speedracerntrixie
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I not only see this with gassers but with all engines. Guys out at the field that have issues getting an engine started then pick up a starter. Sure a starter will turn over a 30cc engine just fine but what I fail to see is why not just spend a little time and figure out why the engine is being difficult to start in the first place. I have heard lots of times " the smaller gassers are just that way " I think it's a cop out. IMO it's just someone not having the knowledge to fix the problem or just being lazy. Granted I have not owned a 30cc but if I did rest assured it would easily hand start. Any engine once dialed in and running predictably will hand start just fine. As far as a big chicken stick or paint roller? You could do yourself even more harm. Imagine the snapping forces applied directly to your wrist in the event of a kick back. Would you rather have some bruised fingers or a fractured wrist? To be perfectly honest, I have not experienced a kickback. Then again I always know exactly what I have in front of me before starting to flip that prop.
Old 01-06-2015, 09:20 AM
  #103  
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That sharp APC trailing edge makes this type of prop the most efficient at converting revolutions to thrust. Too bad that practically all (a couple notable exceptions) engine makers still use the multi bolts to secure props. You don't want to drill 4-6 bolts holes in an APC hub
Old 01-06-2015, 09:31 AM
  #104  
ahicks
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SRT, I'd agree with you to a point. The 20 - 30cc engines are generally really easy to flip start (OK, might be a little challenging for some newbies). On the other hand, the baby gassers (like the Evo 10), while they can be hand started, they'll try the patience of a saint. People will be happiest if they just plan on using a starter going into it with them. Especially when cowled. -Al
Old 01-06-2015, 11:03 AM
  #105  
speedracerntrixie
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Al, I have no issue with that, even up to a 20cc I would not fault a guy for using a starter. I just feel that anything larger one runs the risk of having the starter slip off the spinner and then you have a guy falling onto an airplane that is being pushed towards him. I wouldn't worry about it as much if I hadn't seen it happen a couple times. Just for the record, I have a couple 4 stroke glow engines that I would never attempt to hand start and do use my 25 year old Dynatron. My experience with poor starting gassers is that every time it happens to me I find something wrong and then it went back to being easy and predictable.
Old 01-06-2015, 11:15 AM
  #106  
av8tor1977
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I have converted and sold numerous Echo 21 to 25cc engines from yard equipment, and fly a couple of them myself. Even when equipped with a magneto they are no problem to hand start.

AV8TOR
Old 01-06-2015, 11:28 AM
  #107  
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Originally Posted by MTK
That sharp APC trailing edge makes this type of prop the most efficient at converting revolutions to thrust. ...
That sharp trailing edge also makes nasty cuts in bare fingers trying to hand prop the engine. It also cuts deep on a kick-back. I use them because they are the best performing on my up-to-1.08 glow engines, but I prefer a more scale looking prop for my bigger engines, both gas and 4 stroke glow.
Sincerely, Richard
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Old 01-06-2015, 05:31 PM
  #108  
ahicks
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That sharp trailing edge easily dealt with using 120 grit sandpaper. I'm not going to say I've never been cut because the minute I do, that will change. I will say ALL of my APC and MAS props are sanded and balanced carefully prior to use. I guess I prefer my skin to efficiency?
Old 01-06-2015, 05:48 PM
  #109  
speedracerntrixie
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APC props go on everything glow in my hangar. I clean them up and actually sharpen the TE more. When the aluminum molds get worn they are re-machined to a next size up. This leaves a barely noticeable ridge about 3/32 off the TE. We have found you can actually pick up a couple hundred rpm by removing this ridge. I agree and would never think about hand flipping these, my 4 strokes get a starter and my 2 strokes are bump started. A well set up glow 2 stroke is very easy to bump start, simply slightly over prime, attach glow driver and give the spinner a quick flip clockwise.
Old 01-06-2015, 07:10 PM
  #110  
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[QUOTE=speedracerntrixie; A well set up glow 2 stroke is very easy to bump start, simply slightly over prime, attach glow driver and give the spinner a quick flip clockwise.[/QUOTE]

Yeah, some people freak out when they see me do that. Some of my friends say "Engines are afraid of you and always perform perfectly." No magic, just decent tuning, maintenance, and knowing your equipment.

AV8TOR
Old 01-07-2015, 05:36 AM
  #111  
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Originally Posted by ahicks
That sharp trailing edge easily dealt with using 120 grit sandpaper. I'm not going to say I've never been cut because the minute I do, that will change. I will say ALL of my APC and MAS props are sanded and balanced carefully prior to use. I guess I prefer my skin to efficiency?
+1 to that. I use paint on the tips to balance. How do you balance them? Also I check the tracking, but if one is out, I don't use it. Any way to correct for blades not tracking, except to return it?

Sincerely, Richard
Old 01-07-2015, 07:55 AM
  #112  
ahicks
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Re: balancing, I just use a Highpoint balancer - after sanding, and if necessary, drilling for correct shaft size.

I've never bothered checking APC and MAS tracking. You're failure rate saying I should? -Al
Old 01-07-2015, 07:59 AM
  #113  
HoundDog
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Hey it time to go to Electric .... Start
https://www.youtube.com/watch?v=2UfxyF2O4Q8

http://www.milehighrc.com/EME_E_Start.html



https://www.petenplanes.com.au/engin...prod_1472.html

https://www.youtube.com/watch?v=bSeXm6VTTCc
Old 01-07-2015, 10:26 AM
  #114  
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Originally Posted by ahicks
Re: balancing, I just use a Highpoint balancer - after sanding, and if necessary, drilling for correct shaft size.

I've never bothered checking APC and MAS tracking. You're failure rate saying I should? -Al
No, not really. Only with wood props. I thought I had a tracking issue with a MAS on a Zenoah G23. Actually I did have a tracking issue, but it was a bent crankshaft stud from the previous owners crash. Replaced the shaft and all was good. I do have a dial indicator to check shaft run out/and prop tracking. I use piloted counterbores for prop hole enlargement. Seems to work.

Sincerely, Richard
Old 01-10-2015, 11:52 AM
  #115  
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Well, after about 3 years of hand starting gas engines I just got my first whack. I was wearing a welders glove so nothing was cut but my middle and ring fingers hurt for a good hour and a half. I could not tell from the pain if the engine backfired or I just didn't get my hand out of the way fast enough. It sure got my attention.

It was a DLE20. I had removed the prop the day before and when I reattached it I didn't quite get it placed where I normally set them. I like the prop to feel compression at about the 1:00 o'clock position. This one was closer to about 2:15. I suspect that difference was the main reason for getting whacked. I did re adjust the prop to about 1:00 o'clock and had no issues on subsequent starts.

So, it got me wondering. Are most hand whacks caused by a backfire or is it because you don't flip it with enough authority to get your fingers out of the way. I would think a backfiring issue would be due mostly to a too far advanced ignition timing.

LOL. I gotta tell you, even a gasser that small gives quite a wallop. It was kind of cold that morning so that probably added to the pain.

Indiomike
Old 01-10-2015, 12:19 PM
  #116  
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Hesitant flipping will get you whacked no matter what technique you use
Old 01-10-2015, 12:28 PM
  #117  
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A bad position for starting the engine, either of the prop or yourself and your hand can get your fingers wacked. Also a weak flip without a good follow through. I believe that is the primary cause. An engine is more likely to backfire if it has too far advanced timing, or if it is flooded. But it shouldn't back fire with a good hard flip with a good follow through stroke. Complacence is noted by an engine quickly, and that's when they bite. The last time I got wacked I had been flipping an engine from behind as I had seen someone do. Turns out that's not a good idea and yes, it does hurt when you get wacked!!

Indiomike: I didn't think anyone lived in Indio!! I love your "signature", and how true!

AV8TOR
Old 01-10-2015, 09:00 PM
  #118  
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Originally Posted by av8tor1977
A bad position for starting the engine, either of the prop or yourself and your hand can get your fingers wacked. Also a weak flip without a good follow through. I believe that is the primary cause. An engine is more likely to backfire if it has too far advanced timing, or if it is flooded. But it shouldn't back fire with a good hard flip with a good follow through stroke. Complacence is noted by an engine quickly, and that's when they bite. The last time I got wacked I had been flipping an engine from behind as I had seen someone do. Turns out that's not a good idea and yes, it does hurt when you get wacked!!

Indiomike: I didn't think anyone lived in Indio!! I love your "signature", and how true!

AV8TOR
av8tor: I will have to agree. Living in Indio is not quite on par with Malibu, Beverly Hills, or just about anywhere else in CA. We have a population of about 85,000. It is horribly hot here from July through September but at this time of year it's pretty nice compared to the cold most of the nation is enduring. I see you are from Lukeville, AZ. Your weather would be similar to ours. Your population is slightly less, 23 people as of 2014 per Google search. I think your nearest Walmart is about a hundred miles away.

Kidding aside, I always enjoy reading your posts as you contribute much good information here.
Cheers
Indiomike
Old 01-10-2015, 10:30 PM
  #119  
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I was just teasing you Indiomike, and thanks for the compliment. Actually I lived in Puerto Penasco, Mexico, 60 miles south of the border from Lukeville for a long time. I recently moved to Tucson, Arizona though. At least in Puerto Penasco, we had the Sea of Cortez to moderate temps a little bit, and to jump into when things got too crazy. I've passed through and flown over Indio many times as I had family in LA for many years and the rest of us lived in southern Arizona. Anyway, hot is hot and I don't care for it; just don't have the bucks to re-locate to a nicer clime, or even better, to move with the seasons. That would be nice...

Much R/C action in Indio? I'm sure it's like here, the summer is the "building season" because it is too hot outside. I once landed in Yuma, Arizona in the summer, and we all walked (ran) towards the flight shack and restaurant. Then I realized I had forgotten something in the airplane and I went back out to get it. It was already so hot inside the airplane that it was like an oven and you couldn't breathe! I then walked into the flight shack and said to the first person I saw "How in the hell can you people LIVE in a place like this??!!" She promptly put me in my place by saying "WELL, it's only you fools passing through that are OUTSIDE DURING THE DAY!!"

AV8TOR
Old 01-11-2015, 06:01 AM
  #120  
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Originally Posted by Indiomike
Well, after about 3 years of hand starting gas engines I just got my first whack. I was wearing a welders glove so nothing was cut but my middle and ring fingers hurt for a good hour and a half. I could not tell from the pain if the engine backfired or I just didn't get my hand out of the way fast enough. It sure got my attention.

It was a DLE20. I had removed the prop the day before and when I reattached it I didn't quite get it placed where I normally set them. I like the prop to feel compression at about the 1:00 o'clock position. This one was closer to about 2:15. I suspect that difference was the main reason for getting whacked. I did re adjust the prop to about 1:00 o'clock and had no issues on subsequent starts.

So, it got me wondering. Are most hand whacks caused by a backfire or is it because you don't flip it with enough authority to get your fingers out of the way. I would think a backfiring issue would be due mostly to a too far advanced ignition timing.

LOL. I gotta tell you, even a gasser that small gives quite a wallop. It was kind of cold that morning so that probably added to the pain.

Indiomike
If U read the instructions from many Electronic ignitions it states that U must start the FLIP 90 Degrees before TDC. This is as a safety measure so when cranking the prop thru by holding one blade it won't fire. I thought I had taken the tips off my first therr fingers hand proping a 50 CC motor when I brought it up aginst the compression a little to fast and it back fired and hit me so hard that it broue the trailing edge off one blade of the 20-10-6 wood prop.
Try Propping a flooded C-182 O-470 230 HP on a hot summer day With out hooking your finger tips over the trailing edge. Trick is don't leave the master o
n.
Old 01-11-2015, 06:44 AM
  #121  
ahicks
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I like the prop at about 1:00, but I've learned not to be critical of others, no matter where they have them. If you're comfortable and used to "flipping" there, and resonably successfull, why would it make a difference in what I thought was "right"?

I don't hand prop anyting bigger than a C 65, for any reason. I'm nervous about it, and I know the engine will pick up on that the minute I stick my hand out in the vicinity of that prop. I know it's just waiting to bite me if I get close enough.
Old 01-11-2015, 08:34 AM
  #122  
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Gas engines larger than 30cc can be hard to use a chicken stick on. They generally start easily and don't kick back. The only time I have been injured starting any engine was when I used an electric starter. The starter shaft broke when the (35cc glow ) engine started then my hand went into the spinning prop due to pressure needed to engage the spinner. Use a glove, but I don't recommend chicken sticks for larger engines. All my gassers start by hand. The ignition modules make starting much easier than the mag setups.
Old 01-11-2015, 12:43 PM
  #123  
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I was diagnosed with a rotator-cuff injury a couple of years ago. Pretty much had to chalk it up to hand starting engines. Wasn't interested in buying and then lugging a battery and a starter around so my M.D. did a range of motion study and we figured that setting the prop at the 10 or 11 o'clock position allowed me to flip the prop and NOT use the rotation part of the movement. All the range of motion was straight down instead of up, and over.

Injury healed and my hand now gets out of the way a lot quicker. It was a little weird at first, but I got used to it fast.

I use a heavy leather glove and I sand the trailing edge of injection molded props.

Engine sizes range from .15 glow to 62cc gas.

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