Clutch and fan keep coming off

[LynyrdSkynyrd]

My 50 had its maiden flight this past Saturday. Fueled up and had a few of the proz on the flight line help me track in and finish some radio programming and then one of them flew it around till we ran out of fuel. Refueled and tried to restart but the fan and clutch came loose right away and locked up everything. Took it home and got it fixed. Went out yesterday afternoon (Sunday) and got my first flight in on a full tank. As soon as I refueled and tried to restart, same thing happened. I am getting the fan and clutch as tight on the crankshaft as possible but it keeps happening. I thought maybe oil on the nuts and bolts could be loosening up the loctite so i wiped some of them down with acetone and dried them before putting it back together. I will find out tomorrow if it does the same thing but wanted to know if you guys have any suggestions. Btw the canopy in the pic is the original plastic one. Since this was taken i changed it to gloss black.

[R-4-L]

yes, this happend to me alot during my first few tanks of flights, I got so used to it that everytime I wana start my engine, I loosen the glowplug abit, then without the glow heater, I use the starter to release some fuel that's inside..

yea its actually the flood that makes the engine locks and then instead of rotating the crank shaft, your starter rotates the fan..

now i don't seem to have this problem, after 2 gallons of fuel that is.

.. so loosen the plug, rotate the crank, tighten plug, start the engine.

hope it helps..

Ali

[flyinfool]

You did not mention Loctite in your description of installing the fan.
I use blue Loctite on the fan threads and red Loctite on the nut.
Make sure that you give the Loctite 24 hours to reach full strength.
I have never had a problem getting it apart when I wanted to but never had it come apart on its own.

[capebob]

In case it comes loose again here are some thoughts:

How are you tightening the fan nut? This sucker has to be gorilla tight and holding on to the fan with a towel will not do the job. You really need to lock the crankshaft and then tighten. There are several ways to lock the crank. First there is a crank locking tool that screws into the glow plug hole. Do not use this tool. It is ok for R/C car engines but the tops of our pistons are too thin for this tool. If you use this tool and tighten the fan nut properly you will dent in the top of your piston. Most people remove the carburetor and stick a plastic toothbrush handle into the induction port. This works, but isn't the best. Whatever you do, only put plastic into the intake port. If you put something metal in the port and tighten the fan nut you will damage the crankshaft and/or the crankcase. The best tool to use is one of these.

http://www4.mailordercentral.com/heliproz/images/RVO1007.jpg

This little gem is made by Revolution and works with all heli engines 30-91 The part number is RVO1007 and is available at your favorite purveyor of helicopter parts. About $15.

One more thought, you can prevent flooding on your engines by fueling just before flight or having some method of clamping off the fuel line after fueling.



Bob

[LynyrdSkynyrd]

"Off with his head" That might be the problem. Someone here claiming to be a heli "pro" (although I think he's a pot-smoking moron) told me under no circumstances put any loctite in the fan threads and only use blue on the nut. Yesterday I came to the final decision he was an idiot and put loctite in the fan threads. Before that it was only blue in the nut. I will run and get some red for the nut itself. Thanks though that would probably be why. You guys are great. :D

[BarracudaHockey]

Get the crank lock tool and 2 spare clutch bolts.

Put the crank lock in the back of the engine and the spare bolts in the 2 holes you don't use to mount the clutch with about 4mm or so sticking out.

Clean the threads as you did and apply blue locktite, screw down the fan then use a screw driver between the bolts as a lever and tighten down the fan, don't break anything.

Blue locktite the nut and put it on with a socket wrench getting it good and snug and let it sit for 24 hours as flyinfool said.

And like Capebob said, get a fuel line clamp and release it when you are ready to crank the engine.

[playfair]

When I was having this problem it was due to holding the fan in a towel when tightening the nut.

No matter how tight you make it, the fan backs off the crank shoulder a little as the nut gets torqued, making the "assembly" loose. Never had a problem since notching a pvc pipe to lock the crank via the pin/connecting rod.

[flyinfool]

BarracudaHockey,
The blue is probably adequate for the nut but I have red on hand so I use it.
I never had a problem when I used blue on both the fan and the nut.

[quote]"Off with his head"[/quote
I agree :shock:

[Janek]

Don't use red loctite if you have the standard plastic fan.

To remove anything stuck with red loctite you have to apply heat, and plastic fans don't like heat.

As someone has already said, get a proper engine locking tool, and use spare bolts in the fan to crank it down, blue loctite on the fan thread and nut will do, red isn't necessary.

[HelicopterJohn]

LynyrdSkynyrd,

Usually the reason the fan nut loosens up is a slightly flooded engine.

You didn't mention your engine starting technique. This can be an issue that will lead to the fan and associated nut coming loose.

I use a fuel cutoff devise (I think KSJ makes them). Here is my method for starting and I don't have any issues with the nut coming off.

When I am done flying and go to the helicopter I immediately activate the fuel cut off devise to ensure no more fuel goes to the engine. My startup procedure is turn the radio on, connect the glow plug, get my starter ready and the last thing is to de-activate the fuel cut off devise.

Like others have suggested, when I install the fan I clean the threads on both the nut and the crankshaft and apply (blue Loctite) to the nut threads. I use a tool similar to what "capebob" pictured to hold the crankshaft while tightening the nut.

Just something you might want to consider.

:)

[R-4-L]

I second HelicopterJohn,

this is exactly how I start my engine now, when I first built my engine, I used that tool and blue on fan, red on nut.. fly the next day, after several failed attampts (engine flooded that fuel started to come out of muffler), the fan unscrewed.

[LynyrdSkynyrd]

What I have been doing up to this point is removing the back plate on the engine, using a toothbrush with a solid plastic core w/silicone coating and stop the crankshaft up to tighten the bolt. Actually HelicopterJohn, I have two fuel cutoffs now that you mention it. One going to the engine and one going to the refueling point. I have been doing what you mentioned shutting off the engine and closing that cutoff right away. Then I refuel, get everything ready, send fuel to the engine again and then try again to start it. Flights #1 and 2 had this problem Sat & Sun but everything went spiffing yesterday and I think I'm good. I'll upload a picture of machine later. I found if you get a good coat of the Krylon Fusion to stick to the canopy, then use can use spray on dope same stuff you'd use on fabric for planes for a final color. Its not chipping off and the fuel is not eating it either.

Btw, you'd suggest I wait until I have a metal fan before I start using red loctite? Sounds good. Are QuickUks fans good? Or who else would you suggest?

[HelicopterJohn]

Btw, you'd suggest I wait until I have a metal fan before I start using red loctite? Sounds good. Are QuickUks fans good? Or who else would you suggest?

I am sure some use the metal fans and they may provide better cooling but unless you are having some specific problem with the plastic fan I would spend my money on fuel.

Just my thoughts on the subject.

:)

[flyinfool]

Johns right.
The very best beginners upgrade to a Raptor is another case of fuel.

[DavidH]

Yesterday I came to the final decision he was an idiot and put loctite in the fan threads. Before that it was only blue in the nut. I will run and get some red for the nut itself.

I don't use Loctite on the engine crankshaft or the nut. Don't have any problems. I do use a crankshaft locking tool like pictured above. Loctite is really not needed if the nut is tightened properly.

David

[greenmeanie]

I also used this method before.


What I have been doing up to this point is removing the back plate on the engine, using a toothbrush with a solid plastic core w/silicone coating and stop the crankshaft up to tighten the bolt. Actually HelicopterJohn, I have two fuel cutoffs now that you mention it. One going to the engine and one going to the refueling point. I have been doing what you mentioned shutting off the engine and closing that cutoff right away. Then I refuel, get everything ready, send fuel to the engine again and then try again to start it. Flights #1 and 2 had this problem Sat & Sun but everything went spiffing yesterday and I think I'm good. I'll upload a picture of machine later. I found if you get a good coat of the Krylon Fusion to stick to the canopy, then use can use spray on dope same stuff you'd use on fabric for planes for a final color. Its not chipping off and the fuel is not eating it either.

Btw, you'd suggest I wait until I have a metal fan before I start using red loctite? Sounds good. Are QuickUks fans good? Or who else would you suggest?

[LynyrdSkynyrd]

So far so good. Got flight #3 in and no problems at all (except that I hate that training gear and CANnot wait to get better). Went and got the crank lock tool that capebob suggested. $10 through my hobby guy and well worth the money.

[HelicopterJohn]

LynyrdSkynyrd,

Glad to hear you are having success.

Have Fun !!!!!!!

[R-4-L]

I believe taking off the training gear from now would do you good.. when i started learning how to hover, i had training gear and it will wobble and keep me trimming all day.. and worse, the wobbling bent my main shaft..

as soon as I took them off, I flew better and was more comfortable.. the weight of these things really change the flyability of the machine.

just my opinion..

[LynyrdSkynyrd]

Yeah I thought that might be the case. Got another flight in yesterday. Was getting kind of nervous because with the training gear on I would get about 5 or 6 seconds in the air and then the thing would start shaking. After a second or 2 it gets so bad it makes me pretty nervous. I decided it had to be the training gear and took it off. Considering it was slightly breezy yesterday and I've never run without the gear I was hoping not to smash the thing to crap (especially with my wife watching who is not particularly fond of thing anyway.) However I was able to mantain a steady hover with no gear and flight #4 finished well with no shaking or wobbling.

[ClayK]

Are you using Rotopod gear? Mine shakes with Rotopod gear on. I touch mine down real quick on one leg to stop the shaking. Take it off, throttle is more crisp, vertical lift is more crisp and no vibration from gear. Just in my experience though.