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Maiden Flight Snafu! Prop problems. Help!

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Old 05-19-2010, 03:22 PM
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Brian Patrick
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Default Maiden Flight Snafu! Prop problems. Help!

Today was suppose to be the maiden flight for my Mini Pulse XT. I get it out on the runway, and just rev the electric motor to make sure nothing crazy like the prop flying off doesn't happen. And so guess what happens...it fies off within seconds. Strange, I think to myself! I pick up all pieces and put them back on, tightening down the propeller nut a little bit stronger this time. Again...I give some throttle, and the prop goes flying off. Son of a...! Okay, I take it all apart and find that the little aluminum chuck that goes on what amounts to the bolt (these two together make up the adapter) and it seemed really stuck on. The bolt and chuck (again, these both make up the adapter) were not loose. So I was able to get them unfrozen, so to speak, and I thought to myself, "okay...things should be fine...maybe tightening the prop nut on this thing didn't allow it to fully grip the motor spindle. So, this time, I put everything back on, again paying attention to put the prop on correctly, with the print on the prop facing outward. I gave the plane throttle, the prop spun, just like before, and nothing popped off, so I felt I was good. So...I started the maiden flight, and she took off and was in the air around 3 feet off the ground, when the prop flew off once again. That's it! I headed home. So, here I am hoping someone out there knows what I must be doing wrong. I do tightened down the prop nut well, but I don't do it so hard as to risk stipping any of the threading on it. Help!!!???

I've looked at the instruction manual enough to be confident that all is installed correctly.

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Old 05-19-2010, 03:31 PM
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Default RE: Maiden Flight Snafu! Prop problems. Help!

As you tighten the nut, the screw pulls through the outer ring and squeezes the collet onto the shaft. The tighter the nut, the better grip the collet gets.

Sounds like either:

1) It's not tight enough

or

2) you have the wrong size collet

The collet should slide onto the motor shaft, but it should have little if any play. IF it has play in it, it might be too big. You CUOLD try adding a paper shim between the collet and the shaft
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Old 05-19-2010, 03:41 PM
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Default RE: Maiden Flight Snafu! Prop problems. Help!

The fit between collet and shaft is appropriate, which is to say, there is very little wiggle room there! Even if I wanted to put a paper shim in there, I'd not be able to...just no room. I can try really torquing the prop nut down even more, but the tread is aluminum, so I don't want to strip it.
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Old 05-19-2010, 07:33 PM
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Default RE: Maiden Flight Snafu! Prop problems. Help!

Sometimes there is slippage between the two pieces of the prop adapter.
Sometimes, when you are tightening the prop nut, the tapered / threaded shaft adapter (that slips over the motor shaft ) will turn along w/ the prop nut...it will slip inside the internally tapered "female" or the knurled thrust washer part that engages the prop..ya know what I mean?
The prop driver is getting a good bite on the back side of the prop, but the inner, threaded shaft part is slipping in the prop driver...
Take a close look as you are tightening the nut...look to see if the threaded shaft part is turning along w/ the nut as you tighten it...use an open end wrench so you can observe. (if you were using a socket, you wouldn't be able to see what might be happening )
I had that happen, so I cut a slot for a screw driver in the end of the shaft, so I could keep the shaft from turning (w/ a screwdriver ) while I tightened the nut.

Another thing to check for is to see if you are running out of threads. Look to see if the nut is bottoming out before it gets tight enough on the prop. A washer/shim might be all that's necessary?
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Old 05-19-2010, 10:08 PM
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Default RE: Maiden Flight Snafu! Prop problems. Help!

Here are pics of my set up:






And when I got down to the collet, it wouldn't budge, so it was tight at least. Sounds like the prop nut?


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Old 05-19-2010, 11:49 PM
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Default RE: Maiden Flight Snafu! Prop problems. Help!

You might need to trim a little off the threaded portion of the adapter shaft? The cone nut might be bottoming out...not threaded deep enough, so it's not providing enough clamping force.
Or you could try another washer under the nut...or a regular hex nut.


Another thing...it looks like you have the prop washer in between the prop and the back half of the spinner? The prop washer should go on after the back part of the spinner.

With that type of spinner, the order should be...prop...then back of spinner...washer...nut...then spinner cone.
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Old 05-20-2010, 09:37 AM
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Default RE: Maiden Flight Snafu! Prop problems. Help!

Proptop, I have the washer where I have it because that is how it is pictured in the manual's photo instructions. I can try it your way. Doesn't seem like it would make a difference though. Will it?

The manual's instructions/photos show this: motor shaft (spindle), adapter, prop, washer, back-half of spinner, prop-nut, and spinner cone. Is that inappropriate? If so, E-Flite needs to know about it.

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Old 05-20-2010, 10:00 AM
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Default RE: Maiden Flight Snafu! Prop problems. Help!


Quote:
ORIGINAL: proptop

The cone nut might be bottoming out...not threaded deep enough, so it's not providing enough clamping force.
Or you could try another washer under the nut...or a regular hex nut.
I was thinking the same thing. Add a second washer. I'll bet that will fix it
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Old 05-20-2010, 01:39 PM
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Default RE: Maiden Flight Snafu! Prop problems. Help!

Second washer added, and problem solved. I went to try the maiden flight once again. This time, there was a brief bounce on take off, and the prop hit the pavement, and shattered. So...back to playing the waiting game as I order a new prop. I'll order two. Thank you all, for your help with this!
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Old 05-20-2010, 04:19 PM
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Default RE: Maiden Flight Snafu! Prop problems. Help!

Ahhh...the joys of r/c flying!
Ya having fun yet?

One washer behind the spinner might be necessary to keep the spinner from rubbing the cowl? It's not really critical...glad to hear that a 2nd washer helped.[8D]
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