700 Rookie Mistake

Geena

Staff member
So. I take my NX7 out to the flying field last Saturday, to break in a fresh engine. Fuel it up, get the electronics fired up, and attempt to start the engine....YS 96SRX.

It hydrolocks, and I hear a snapping sound...then no compression. Today, I decided to tear it apart, and survey the damage I did to my engine.

I get the engine out of the helicopter, and pretty much dread pulling the head off. Fearing I`m what going to see when I open it up.

As I`m getting ready to pull the head, I decide to turn the engine over by hand, and what do I see through the exhaust port? The piston is not moving at all.

Guess what knucklehead forgot to locktite the crankshaft nut!! Hahaha.....the hydrolock was enough to allow the starter to break the nut loose, and let the fan/clutch hub to spin on the crankshaft. Ooooopsie...LOL.

Ah well...it happens to all of us at times. I`m just happy that was all that went wrong. It`s back together now, AND with locktite this time...and ready for another trip to the field.

Tony....I KNOW you`re gonna have fun with me about this one... baaaahahahahahahaha.
 

D.O.G.

Goblin 380 Supporter
I'm sorry to here about that Geena but at least we know your are human, even though your a great pilot :).
 

Geena

Staff member
I'm sorry to here about that Geena but at least we know your are human, even though your a great pilot :).
I`m more than willing to admit when I screw up...LOL. I`m just glad that`s all it was. It took more time to remove and reinstall the engine, than it took to fix the problem...lol
 

Tony

Staff member
I actually have nothing to say about this one, I have been there. Hell when I started reading this, I thought you had broke the crank nipple where the rod goes on. I have done that before. Never by starting it, but by modifying the engine and over revving the ever loving hell out of it going down a back straight. But man was that thing fast :bolt: lmao

With what you have done to your poor read headed step children, I'm glad to see it was an honest mistake that if it would have started, would not have ended in tears... again.... lmao
 

Geena

Staff member
I actually have nothing to say about this one, I have been there. Hell when I started reading this, I thought you had broke the crank nipple where the rod goes on. I have done that before. Never by starting it, but by modifying the engine and over revving the ever loving hell out of it going down a back straight. But man was that thing fast :bolt: lmao

With what you have done to your poor read headed step children, I'm glad to see it was an honest mistake that if it would have started, would not have ended in tears... again.... lmao
LOL... yeah, I do mistreat them quite a bit...and I`m really happy that it didn`t start too. That could have gotten really ugly....really fast.
 

Tony

Staff member
Eh, now that I think about it, the starter nut is also connecting the cooling fan to the engine (I think Gaui is the same mounting style as Align) so yea, the engine would have over heated and possibly burnt a hole in the piston. So yea, this is the best possible way it could have ended.
 

Geena

Staff member
Yeah, they all mount pretty much the same way. Not much you can do to change that, due to the design of the crankshafts. Would not have been the first time I vented a piston though, if it had started. But I`m still glad it didn`t. Nothing hurt but my pride this time around....hahahaha.
 

Admiral

Well-Known Member
I have a similar tale of wow with the X3 build, during final setup fired it up without any blades on to check the motor was running the right direction, gears all meshing OK etc, next second BANG and everything stopped ??
After that could only get a quarter turn out of main rotor ? stripped out main shaft & main gear nothing ? checked the tail, there was the problem the retaining pin in the tail rotor shaft had moved and hit the umbrella gear knocking the bottom off about 3 teeth, so that's what that miniature grub screw was for ! All good new parts will arrive today and I'll be ready to fly Saturday.
 

Admiral

Well-Known Member
Pucci strikes again, this time the engine. LMOA, at least your tail hasn't fallen apart yet.

I hope it doesn't LOL, the strange thing was a compete tail case with gears, shaft and bearings was only $4 dearer than the gears on their own.
 

murankar

Staff member
Justin pucci built an entire 700 tail assembly without lock tight. It slipped his after doing an all night build.
 

Geena

Staff member
Pucci strikes again, this time the engine. LMOA, at least your tail hasn't fallen apart yet.
I actually broke the tail control horn in flight, doing piro flips a few months ago. Landed that critter with no other damage than the broken horn.

broken tail.jpg
 
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