rcfury

My Feedback: (5)

Hey,
Im having some issues with my Ripper's prop nut for the 15fx. What the problem is that the prop nut keeps on comming loose no matter how much i torque down on it. What it is that the threads on the nut is in the same direction the motor spins so when i come to start it with my starter is loosens it up a little, then after a bit the propeller will just spin freely. I kinda dont want a propeller spinning near 7k rpm come flying off and hitting someone in the pits. Could I add loc-tite to the threads and keep it from comming loose? Or maybe a lock washer? What are some of your sugestions?

rrh

What are you tightening it with? I use an allen wrench or a screw driver that fits the hole in the nut. On the .15s I sometimes bend the screwdriver to get it tight enough, if I'm not careful. There is probably a hardened piece of something that would make the perfect nut wrench, but I haven't found it yet, maybe music wire. Sometimes I cut my fingers on the prop if I haven't scraped the flashing off well enough. That's how tight I am twisting mine down. I wouldn't use Loc-tite, you might not get it back apart after you shear both prop blades off.

rrh

rcfury

My Feedback: (5)

the prop nut came with a small rod which will fit inthe hole in the nut. Maybe im not tightening it enough but not to the extent where the prop will cut me.

Matt Kirsch

My Feedback: (21)

You're not tightening it enough, OR, you're flooding the engine. The sure sign that the engine is flooded is if the engine won't turn over continuously with the starter. It'll turn over for part of a revolution, then lock up HARD.

Don't try to force the engine if it's flooded and hydro-locked like that. You'll bend the rod. Instead, you need to drain the excess fuel out the muffler, clear the engine, and try again. Possible causes are the tank being too high, the needle valve being open too far, and overpriming.

Still, you probably just haven't tightened the prop enough. If cutting your hand on the prop is a concern, use a rag or leather glove to hold the prop while you tighten it down. Use some muscle.

You would think that the use of a right hand (standard) thread on the engine crankshaft is a dumb move. I mean, every time you go to start the engine, you're loosening the nut right? Well, there's a method to their madness. When the engine is running, it's actually tightening the prop nut each time it fires due to inertia. If they used a left-hand thread, you wouldn't be able to keep a propeller on the engine; it'd just spin the prop nut right off!

Montague

It does sound like you don't have it tightened down enough. When I tighten mine down, I usually am holding near the end of the prop in one hand, and a screwdriver handle about the same length in the other, and I give it a good hard squeeze. (I keep pliers in the field box to get props off when both blades are broken, since with out the leverage, they will never come off). I also ususlly use a few layers of paper towl or something to keep the prop from cutting in to my hand. Though I do it bare-handed in a pinch. It doesn't atually break skin, but it does hurt a bit.

lownslo

This is just a thought.............. are the crank threads just a hair to long, and the crank is bottoming out in the spinner hub's threaded hole. Try a second washer, temporarily, and see if that helps. .....lownslo

c/f

My Feedback: (1)

This was my first thoughts.

Locktite would definately be a mistake, especially in combat where you need to compete under the clock or why bother?

Secondly, what is going on is the crankshaft is propably long enough that you are either bottoming out in the threads Or against your tightening rod. Is the rod difficult to remove after tightening? The threads in the nut are 5mm so a bottom tap may help to get to the point that it would bottom out on your torqing rod, or you could use the washer that came with the engine underneath the spinner nut.

I use this exact nut on Magnum .15 and this has never once been an issue or concern, even using a bladder and hydrolocking the engine I have no issues. There definately is something wrong other than the nut.

rcfury

My Feedback: (5)

yeah.. Looks like the crank was just a tad to long and i was hitting the end of threads on the prop nut. I put the washer behind it and it seems to work now.. later i will probally hack a few threads off the crank.
thanks for all the replys..

c/f

My Feedback: (1)

Hacked cranks make for poor resale. The prop nut needs to be tapped deeper, if it is tapped deep enough the crankshaft will bind up against your torqing rod alerting you to the need to add a washer.

rcfury

My Feedback: (5)

yeah that is understandable that hacking the crank will probally get frowned upon, i plan on using this motor till it dies. Actually ill probally end up getting another motor pretty soon anyway.