Magnum/ASP engine failure

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The Raven - 08 Feb 2009 08:44 GMT

Today my ASP 80 RFS was flying along nicely for 10 minutes and then, as I
backed off the throttle after a lowish pass, the engine went bang and came
to a sudden stop. I immediately lowered the landing gear and managed a
reasonable dead-stick landing. On the ground it's apparent something has let
go in the engine, most likely the rod/crank pin.

I've yet to disassemble the motor to assess the damage but as I've never had
this type of failure before I thought it worth asking around.

Have you ever heard of this occuring on Magnum/ASP four strokes? Can you
suggest any reasonable causes...noting that the engine flew perfectly for
the first 10minutes?

Regards

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Ted Campanelli - 08 Feb 2009 22:31 GMT

Ted shuffled out of his cave and grunted these great (and sometimes not
so great) words of knowledge:

> Today my ASP 80 RFS was flying along nicely for 10 minutes and then, as I
> backed off the throttle after a lowish pass, the engine went bang and came
[quoted text clipped - 10 lines]
>
> Regards

Without a tear down it is hard to say.

A more reasonable and likely explanation is a valve keeper let go and
you dropped a valve into the engine. If that is the case, it may be
cheaper to replace the engine than to try and repair/rebuild it.

I would think that a bad wrist pin (or rod) would be making some type of
noise for awhile prior to it letting go.

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Joe - 10 Feb 2009 00:41 GMT

> Today my ASP 80 RFS was flying along nicely for 10 minutes and then, as I
> backed off the throttle after a lowish pass, the engine went bang and came
[quoted text clipped - 10 lines]
>
> Regards

Try going to google groups and sezrching on "magnum". There's a ton of
stuff there.

Here's the URL that appears upon searching, per above:

http://groups.google.com/group/rec.models.rc.air/search?group=rec.models.rc.air&
q=magnum&qt_g=Search+this+group

Have fun.

--- Joe

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Smee - 02 Mar 2009 04:44 GMT

I have had an ASP 120 break a rod in half in flight.

> Today my ASP 80 RFS was flying along nicely for 10 minutes and then, as I
> backed off the throttle after a lowish pass, the engine went bang and came
[quoted text clipped - 10 lines]
>
> Regards

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Model Forum / Radio Controlled / Air Models / March 2009

Magnum/ASP engine failure