McCoy lost power!

[Larry Wong]

This happen Sunday to one of are flyer , RM was covered with shrink wrap for shipping.

[john e. holliday]

Did some one forget to tighten head screws or the thread strip?  

[Larry Wong]

From the looks, it was from a estate sale collector, engine was taken apart and the person assembled it not knowing 3 long bolts hold cylinder and head and 3 short bolts hold the head.

[Brett Buck]

When they said "drop the liner", they didn't mean in the weeds.

    Brett

 

[Brad LaPointe]

I never have seen a McCoy with enough compression to do this . Must of been a piece of metal jamming the top end .

Brad

[frank mccune]

     To think that only I had unique engine problems!  Seeing this post makes me feel much better. Lol

      Frank

[Carl Cisneros]

I had that pretty much same thing happen way back in around '74.

Running my buster in a club race with a McCoy 35 Series 21 on it.
Was using 25% nitro fuel and a 9 something prop on it.
It started to wind up more so than usual then all of a sudden, complete silence and we all saw the top end leave the motor.

Found the long screws had broken flush with the case.

Everyone had a good laugh.

Carl C

[Brett Buck]

I never have seen a McCoy with enough compression to do this . Must of been a piece of metal jamming the top end .

  I had the same thing happen with an Olhsson 23 Sideport, it had no compression to speak of, either. The 35% nitro might have had something to do with it.

    Brett

[Brett Buck]

70 year old pot metal bolt holes.

   It's aluminum, not pot metal, but after 70 years of everybody thinking they are engine genii, who knows what state it is in.

    Brett

[Steve Helmick]

Obviously, not enough castor oil in the fuel. That defect in the propeller probably didn't improve the thrust, either.  Steve

[Brett Buck]

What do you think pot metal is according to the metric system.

  Pot metal is not defined (just whatever easily-meltable non-ferrous mix they have that day) but is largely zinc. Old Perfect wheel hubs were pot metal.

     Brett

[Dennis Adamisin]

Same failure mode as my dad's last McCoy 40 on his Dewoitine D520.  In his case stripped bolts.  Died in OH8, got just enough recovery to put it in a pancake position, broke much more than prop...

[Brett Buck]

Same failure mode as my dad's last McCoy 40 on his Dewoitine D520. 

     I remember that airplane, it was at the first contest I ever attended - as a 10-year-old spectator. It didn't crash that day, but I don't think it won, either.

    Brett

[GallopingGhostler]

From the looks, it was from a estate sale collector, engine was taken apart and the person assembled it not knowing 3 long bolts hold cylinder and head and 3 short bolts hold the head.

Those bolts only go in one way. The longer will not fit unless aligned with the threaded holes in the crankcase. No one disassembled engine prior to mounting, just to make sure assembled correctly? I had an RH that someone mounted the piston backwards where the piston top baffle was on the exhaust side instead of the bypass side.

[proparc]

I read this post because the the title read "McCoy lost power"? I want to know just exactly where did you get your hands on a McCoy that had power???

[Brett Buck]

I read this post because the the title read "McCoy lost power"? I want to know just exactly where did you get your hands on a McCoy that had power???

   I am pretty confident that it had less power after the cylinder flew off. But not certain.

    Brett

[GallopingGhostler]

I am pretty confident that it had less power after the cylinder flew off. But not certain.

Someone mistook it for a Fox .15 and attempted to throw it?

[John Park]

I once tried a compression-restoring trick on a clapped-out Testors McCoy .19 - the one where you put the piston, skirt down, on a surface plate, hold a piece of 1/4" brass rod centred on the crown, and deliver a couple of smart blows with a hammer. Astonishingly, it seemed to work: the engine started easily, and ran well enough to fly a lightly-built SNAFU Magician through the old-time British stunt schedule at Old Warden in 1976.

[Dan McEntee]

I once tried a compression-restoring trick on a clapped-out Testors McCoy .19 - the one where you put the piston, skirt down, on a surface plate, hold a piece of 1/4" brass rod centered on the crown, and deliver a couple of smart blows with a hammer. Astonishingly, it seemed to work: the engine started easily, and ran well enough to fly a lightly-built SNAFU Magician through the old-time British stunt schedule at Old Warden in 1976.

   I think this has been posted before, but I think you are supposed to put the piston in the cylinder at the bottom like you describe, and then repeatedly peen the crown near the edge all the way around with the brass punch. Then you may have to lightly lap the piston back into the cylinder a bit before trying to run it. I think Jim Kraft has done this so you may want to include his name in the search for it.
  Type at you later and MERRY CHRISTMAS!!!!!
  Dan McEntee

[Ken Culbertson]

I read this post because the the title read "McCoy lost power"? I want to know just exactly where did you get your hands on a McCoy that had power???

They had plenty of power for an engine that was basically crap.  Back in the day a money strapped teenager had two choices, an expensive engine that underpowered your Nobler and would last till you crashed and ruined it or a cheap one that would last till you crashed and ruined it.  If you could manage to get a McCoy broken in before it wore out, it was just as good as a Fox for it's expected life.

Ken

[John Park]

They had plenty of power for an engine that was basically crap.

I got my .19 for nothing!  A friend had flown it in a succession of British combat models (3.5cc max. engine size) until it had next to no compression, so I tried the crude fix described above. It had about as much power as a plain-bearing 2.5cc diesel when I ran it on 5% nitro fuel - which was all I could afford in those days!

[Brett Buck]

Someone mistook it for a Fox .15 and attempted to throw it?

  I know you are trying to be humorous, but the Hurl Committee takes a dim view of such levity when it comes to a blatant violation of Rules 68/69. We believe that sufficient controls are in place to eliminate such shenanigans with respect to official Hurl competition, and I am sure that no one here wants to leave any sort of misapprehensions when it comes to sanctions for such violations.

    The Hurl Committee/Moderna vaccination program is, of course, front and center, but I am sure we can spare some time to dispense the necessary directives to handle any such violation. Please do not take this opportunity to play fast and loose with The Rules, or there will be consequences.

    Thank you for your continued interest in the international sensation known as The Hurl!

    Brett Buck, Deputy Commissioner of the Hurl (self-appointed)