I hope I didn't trash my Black Widow today

**RknRusty** Thu Oct 27, 2011 8:35 pm

Now that I have two main forums, I end up cross posting between them if I have something i think is interesting to both.

I didn't think an .049 would run without the inertia of the prop, but it did. I was test running it on the Satan, because it started running like crap yesterday. So I was holding the plane in my hand. I had noticed an odd vibration a couple of times. I guess that was the prop shifting.

When it came off, the engine sounded like an electric motor does with a bad bearing. Remember what HO slot cars sounded like when they got dust in the motor, a high pitched BRRRRRRRRR... a horrible sickening sound, like it was seriously galling something. I plugged both vents with my fingers and it wouldn't stop. I went to close the NV and it quit before I turned it.

I put the prop back on and turned it over by hand and everything felt fine. So I figured if the crank housing was shot, the crank and con-rod might be too. So, what the hell, I fueled it up, gave it one flip and it ran a full run, fine and smooth with no bad vibes.

The prop was a well balanced 5.25x3 and it slung it across the shop. I have yet to find the spinner. Anyone ever had this happen? Did it damage anything? No need to lecture me on pre-flighting.

Here is the link to the thread at RCG. I've gotten a bunch of replies so far.

microflitedude Thu Oct 27, 2011 9:07 pm

RknRusty wrote:Now that I have two main forums, I end up cross posting between them if I have something i think is interesting to both.

I didn't think an .049 would run without the inertia of the prop, but it did. I was test running it on the Satan, because it started running like crap yesterday. So I was holding the plane in my hand. I had noticed an odd vibration a couple of times. I guess that was the prop shifting.

When it came off, the engine sounded like an electric motor does with a bad bearing. Remember what HO slot cars sounded like when they got dust in the motor, a high pitched BRRRRRRRRR... a horrible sickening sound, like it was seriously galling something. I plugged both vents with my fingers and it wouldn't stop. I went to close the NV and it quit before I turned it.

I put the prop back on and turned it over by hand and everything felt fine. So I figured if the crank housing was shot, the crank and con-rod might be too. So, what the hell, I fueled it up, gave it one flip and it ran a full run, fine and smooth with no bad vibes.

The prop was a well balanced 5.25x3 and it slung it across the shop. I have yet to find the spinner. Anyone ever had this happen? Did it damage anything? No need to lecture me on pre-flighting.

Here is the link to the thread at RCG. I've gotten a bunch of replies so far.

That's insane! Shocked

How long did it run? Nitroairplane could barley get a cox .049 to run on a 4.5 inch and it snapped the crankshaft.

**RknRusty** Thu Oct 27, 2011 9:19 pm

About 10 seconds.

jetpack Thu Oct 27, 2011 9:25 pm

I wonder if it was just bouncing up to TDC and not past it, just going back and forth a million times lol!

**RknRusty** Thu Oct 27, 2011 9:37 pm

jetpack wrote:I wonder if it was just bouncing up to TDC and not past it, just going back and forth a million times

That's a possibility I haven't thought of. Good guess, but I hope I never get another chance to investigate.

**Admin** Thu Oct 27, 2011 10:01 pm

Ok, so your prop flew off when it was running and it continued to run without the prop? I had this happen to me with a Babe Bee, I always check the prop screw but this time I didn't. The prop flew off, never seen it again and the engine sped up intensely for about 5 seconds and then a "snap". It was all over... The crankcase was alright but the crankpin blew off of the crankshaft. I just tossed a new crankshaft in it and replaced the damaged reed, it ran fine afterwards.

**RknRusty** Thu Oct 27, 2011 10:10 pm

I'm going to tear it down and have a look. Meanwhile I have another BW that's also a fresh build, and has always been the faster of the two. It's on the Jumpin Bean now, so they'll just get swapped.

nitroairplane Fri Oct 28, 2011 4:10 am

Ive had this happen only ever once the engine was not damaged but the glowhead burnt because of the rpm at too lean a setting.

**RknRusty** Fri Oct 28, 2011 11:06 am

nitroairplane wrote:Ive had this happen only ever once the engine was not damaged but the glowhead burnt because of the rpm at too lean a setting.

How long did it run without the prop?

nitroairplane Fri Oct 28, 2011 11:13 am

I dunno times goes so slowly when you are scared Smile

My gues is only about 10 seconds.

PV Pilot Fri Oct 28, 2011 11:31 am

Back in the offroad days, when you might have a flywheel loosen up and slip and would zing the motor up there, it would either survive unscathed or stretch the connecting rod. We called it a "rod slinger". The bog/growl you heard might have been the motor running out of carburation setting.

Check the head filament,,see if the coils have been streched or grayed. Take a peek at the connecting rod socket. If you have a circlip retainer for the reed, maybe take a peek at that also. I had a circlip retainer fail at high free rpms on my cox IMSA car and it pulled the retainer under the connecting rod, seized the motor ,bent the rod, scored the crankcase, junked it basically.

You mgiht have got away scot free Rusty with no harm.

nitroairplane Fri Oct 28, 2011 11:46 am

Ive had similar stuff in my rc cars when the pinion gear strips and then and at full thottle just spins because it wont mesh then usually you'll burn the clutch or glowplug i did slightly stretch the connecting rod.

**RknRusty** Sat Oct 29, 2011 10:17 am

I just tore it down, no metal or galling. All it needs is a couple of piston taps and de-varnishing. The piston pits perfectly, just like in our new write-up about performance Bees. It hangs tight at the top landing and a light tap makes it fall out the bottom. I washed out the crank casing and it spins fast and free with no prop on it. The driveplate may need to be pulled on a little more but I'll have to get my flat feeler gauge and check it. I'm going to try and follow all of those performance guidelines and see how she runs. I may not be able to find the aluminum tube though.

microflitedude Sat Oct 29, 2011 10:38 am

RknRusty wrote:I just tore it down, no metal or galling. All it needs is a couple of piston taps and de-varnishing. The piston pits perfectly, just like in our new write-up about performance Bees. It hangs tight at the top landing and a light tap makes it fall out the bottom. I washed out the crank casing and it spins fast and free with no prop on it. The driveplate may need to be pulled on a little more but I'll have to get my flat feeler gauge and check it. I'm going to try and follow all of those performance guidelines and see how she runs. I may not be able to find the aluminum tube though.

Glad to hear it's ok.

See my other post.

**Admin** Sat Oct 29, 2011 11:34 am

Yeah, its good to hear it will be fine!

**RknRusty** Sat Oct 29, 2011 1:52 pm

microflitedude wrote:Glad to hear it's ok.

See my other post.

You mean this one?:

microflitedude wrote:That's insane! How long did it run? Nitroairplane could barley get a cox .049 to run on a 4.5 inch and it snapped the crankshaft.

It ran 8 or 10 seconds while I fumbled around trying to kill it.

microflitedude Sat Oct 29, 2011 3:19 pm

RknRusty wrote:
microflitedude wrote:Glad to hear it's ok.

See my other post.
You mean this one?:
microflitedude wrote:That's insane! How long did it run? Nitroairplane could barley get a cox .049 to run on a 4.5 inch and it snapped the crankshaft.

It ran 8 or 10 seconds while I fumbled around trying to kill it.

This one ~

"I actually got it from an old kit - it was not mentioned in the plans/manual so I took it out. Probably a throttle cable tube.

I don't think I'l ever use it. If you can help me de-bur a couple .049 cylinders, you can have it. It's 1/10th inch dia. and 5" long."

microflitedude Sat Oct 29, 2011 3:21 pm

Also, if your BW didn't stop when you plugged the vents then you have an air/fuel leak. Make sure the area between the tank bowl and backplate are well sealed.

nitroairplane Sat Oct 29, 2011 5:48 pm

Or air was still entering the tank as you held it which is very possible too.

**RknRusty** Sat Oct 29, 2011 10:43 pm

I may not have squeezed the vents tightly enough. I'm probably going to use a metal plate on it. The old one has a busted ear.

MFDude, a .1 inch tube is about perfect. It calls for 3/32" which is .094". I'd call that a tenth. What have you got, cylinders galled at the port and the piston won't enter the upper cylinder?
If you don't need the aluminum tube I'll put it to good use. We'll have to arrange a meeting.

microflitedude Sun Oct 30, 2011 9:55 pm

RknRusty wrote:I may not have squeezed the vents tightly enough. I'm probably going to use a metal plate on it. The old one has a busted ear.

MFDude, a .1 inch tube is about perfect. It calls for 3/32" which is .094". I'd call that a tenth. What have you got, cylinders galled at the port and the piston won't enter the upper cylinder?
If you don't need the aluminum tube I'll put it to good use. We'll have to arrange a meeting.

Yep, exactly. I worked at it a little, seemed to get better, tried some more then wouldn't move at all. Piston stops midway in the exhaust port. Let me know when you can go in the direction of the school - we play tennis often.

**RknRusty** Sun Oct 30, 2011 10:31 pm

microflitedude wrote:Yep, exactly. I worked at it a little, seemed to get better, tried some more then wouldn't move at all. Piston stops midway in the exhaust port. Let me know when you can go in the direction of the school - we play tennis often.

I can get out there on Tuesday or Thursday. I'm free both days. I'll PM you my cell phone number. My landline number is in the phone book. I'll brink a couple of planes and my tools. I can probably fix it right there. Maybe we can get a couple of flights in.

Sponsored content

I hope I didn't trash my Black Widow today

I hope I didn't trash my Black Widow today

Re: I hope I didn't trash my Black Widow today

Re: I hope I didn't trash my Black Widow today

Re: I hope I didn't trash my Black Widow today

Re: I hope I didn't trash my Black Widow today

Re: I hope I didn't trash my Black Widow today

Re: I hope I didn't trash my Black Widow today

Re: I hope I didn't trash my Black Widow today

Re: I hope I didn't trash my Black Widow today

Re: I hope I didn't trash my Black Widow today

Re: I hope I didn't trash my Black Widow today

Re: I hope I didn't trash my Black Widow today

NO DAMAGE!

Re: I hope I didn't trash my Black Widow today

Re: I hope I didn't trash my Black Widow today

Re: I hope I didn't trash my Black Widow today

Re: I hope I didn't trash my Black Widow today

Re: I hope I didn't trash my Black Widow today

Re: I hope I didn't trash my Black Widow today

Re: I hope I didn't trash my Black Widow today

Re: I hope I didn't trash my Black Widow today

Re: I hope I didn't trash my Black Widow today

Re: I hope I didn't trash my Black Widow today