This is the third time this has happened: On my Hobbico Superstar with OS 40LA, I'm applying the electric starter and suddenly the prop nut comes loose inside the spinnner . This is the stock spinner that comes with the RTF with 2 screws that go into the backplate of the spinner, but the prop is a Master Airscrew G/F 3 series 10X6. From the backplate of the engine going forward: is the back of the spinner, then the prop, then the black flatwasher, then the nut. Seems like on this hard plastic prop there ought to be a lockwasher under the nut, but my other planes don't have one either. I thought I used plenty of torque on the nut since this has happened before. Luckily it's only happened when starting, but worried it could shake loose in the air too. Help!

Torque it up harder. I use a 10 inch adjustable wrench. The small cross wrenches used for tightening the glow plug are not big enough to appply the required torque to the prop nut. Remember that the direction that your starter turns the prop is also the direction required to remove the prop nut. Interesting, isn't it?

Well that's exactly what I used last time! I guess I can torque harder yet. Would a thin compression-type lockwasher between the nut and flat washer make any sense? What about using some threadlock?

More torque. Do NOT use a lockwasher as it will lose it's effect after it's first use and need replacing after each use. Also not the same quality of steel as the other hardware. Also do NOT use threadlockers. I use an 8 inch combination wrench of the correct size so there is NO wrench slippage. Tighten it down, you won't hurt it.

I agree,, more torque I tighten em enough to leave a prop dent in my fingers.

Be sure the spinner clears the prop all the way around.

Torque it up a little tighter is a good idea. I also sometimes use a washer made of a piece of drywall sanding material. It looks like screen wire with abrasive on it. I cut a piece that is twice as big as what I need and fold it over. That way it is doubled and I cut a small hole in the center to go over the crankshaft. It is thin enough that it does not take up enough space to matter. One piece would make dozens of washers. I normally use it between the back plate and prop.

mbilar! I'm not at the moment fully familiar with your set-up but have used the engine and the prop without problems. Here is my set-up for spinners and props. First Unless the spinner is a scale item or a student's cutsey item, I use a spinner nut.
If the spinner is a must:
Take some wet or dry sandpaper, fold over and cut a half-moon about prop washer size then a smaller one for the prop shaft. No need to be precise. TLAR method is fine. That Looks About Right. Use that s/p washer between engine and spinner backplate, grit to backplate. Maybe another between backplate and prop with grit to prop.

Check that when nut is tight it has not tightened against last thread of shaft. HAPPENS! Be certain that threads go inside the washer. Difficult to diagnose so sometimes I just throw in another 1/4" flat washer out of the 1/4" washer pile and that will fix that. [>:]

Now if you're prone to over-choke or prime or it's cold and you allow too much fuel into the engine before it fires, it will be a tad flooded and kick 'er right off. Happens !!

If you're flying below 40* outside, use a prime bottle with 1/2 gasoline and 1/2 glow fuel. When ready to start, do not choke or prime other than several drops in the carb of the prime bottle. Turn/flip the prop several times. Turn on the glow plug and start with throttle cracked at about 1/8 open. Try it -- you will like it. BTW do not use this in your fuel tank. Just for initial cold WX prime. [8D]

By the way, this engine is a very easy starter--I have never used an electric starter on mine in several seasons of use. I just choke with enough turns to bring the fuel to the carb, then one more turn. MAYBE two. You just need a bit of fuel into the engine. Then a couple of fast flicks to get the charge up into the cylinder. Then connect the glow driver and use a chicken stick (a piece of rubber hose from an auto store pushed over a dowel) to give a quick flip. I hardly ever need more than two flicks--usually one.

The only thing tricky about the FPs is that they flood easily--that's why only one or at most two turns choked once the fuel has reached the carb. If it's flooded then you'll probably want to pull out your starter.

Also, try an 11x4 or 11x5 prop on that engine--it will be slower and land easier, but should climb better when you need to get out of a jam.

Jim

This is very interesting. For the first time today I flew my plane on sticks with an instructor and since we didn't have a buddy cord, we handed the controller back and forth. It worked fine. I was far enough along that I only had to hand it to him to land and take off.

However what what was interesting was that I had previously figured out exactly how to start my engine with no trouble in all my breaking in in my backyard: open the throttle full, thumb over the intake and prime the engine about 5 or 6 turns, then apply glow starter, close throttle to about one-quarter, apply electric starter and always an instant start. Today my instructor didn't bother with the priming and just put the glow starter on at quarter throttle and spun away for 10 or 15 seconds until it drew the fuel in and finally fired up. I have nothing but respect for my trainer, but I think I have a better quicker way of starting my engine by priming, and maybe I wouldn't even need the electric starter but I do use it. And my trainer's method is much more abusive on the plastic spinner!

Your instructor's method is the usual--I've done it myself on a scale model where choking is difficult. On most engines in use today there is no reason not to.

But the FPs do not have ball bearings, so when you push the charger against the spinner you're grinding metal between the drive washer and the the crankcase--take a look--you'll see a little grey sludge after a difficult start. It's not an issue in the short run, but eventually that can take off enough metal to cause the crank pin to start hitting the inside of the back plate. And then, as you mentioned, there's the wear on the spinner.

Give the hand starting a try--it's exciting to get an engine going that way. For years I didn't even own a starter--I had the lightest field box in the club. Jim

Either method is acceptable. Priming first you risk flooding the engine if not careful. Not priming first you can grind away metal in non-bearing motors. Do it the way YOU like best.

hand priming is extremely easy on engines mounted upright and i think preferred. at the same time, it checks to see if there are any airleaks you should be worried about.

hand starting... now that's a different story. i've had my fair share of hand starting. my webra (from eons ago) and my O.S. engines can start easily with a chicken stick. but man... i'd rather not have to hand start my ASP or Magnum engines...

as for the spinner... i would make sure that the nut is on tight enough. should stay one without any additional items.

my two cents.

Why should he not use a thread locker????? Locktite would be a wonderful solution to this problem.

You don't use locktite on things that come apart frequently.