> > o.k. so the hush power muffler is
toasting up?
> >
> > best,
> >
> > George W
> >
> > George,
> >
> > "Melting" is more like it. After my initial 20
minute
> flight
> > with the
> > new HP2 muffler, there was "cake frosting"
dripping
> from the
> > exhaust
> > pipe onto the hangar floor. The 304ss baffle
was already
> > beginning to
> > scale.
> >
> > Mark S.
> >
> > Mark,
> > Scaling isn't that bad a thing. I'm not
surprised
> that your
> > glass
> > packing melted. That is to be expected at 1600
F Fine
> scale
> > on the
> > exterior of the muffler wouldn't be uncommon.
Is the
> muffler
> > becoming
> > misshaped? Is the interior screening melting?
I'd like to
> know
> > as I'm
> > trying to get all the stuff together for
my 20B.
> > Bill Jepson
> >
> >
> > Bill,
> > The airplane is currently down for some electrical
mods
> at this
> > time.
> > So, I haven't flown again with the HP2 since the
first short
> > flight a
> > few weeks ago. The strange thing is that I didn't
notice the
> > melting of
> > the fiberglass until I had shut it down. It could
have
> already
> > been in
> > the process of melting with the fiberglass
being blown
> out the
> > exhaust
> > as I flew. I noticed the goo on the hangar floor
after
> it had
> > been
> > parked for 15-20 minutes. It is amazing that
it was
> still hot
> > enough to
> > continue melting the glass long after shutdown.
> >
> > No, the baffle inside the muffler hasn't melted,
but it sure
> > looked like
> > it had been through the fires of hell. We'll see
how it
> holds up.
> >
> > My recommendation is to either place the muffler
3-4 feet
> back
> > from the
> > exhaust ports, or build a muffler from inconel or
thick
> 321ss.
> > Another
> > option would be to turbo-charge and forget the
muffler.
> >
> > I'll report back after I fly again.
> >
> > Mark
> >
> > Is the Hush Power muffler inside the cowl Mark?
> >
> > You have room in there for a huge tangential
muffler with
> > a JB Wagner thick wall 304 SS Jerry Hey cool tube
running
> down the
> > center.
> >
> > You may need to add a patch to the outer or
inner skin
> where the
> > exhaust
> > directly impinges on it.
> >
> > Paul Lamar
> >
> >
> >
> > Paul,
> > I was hoping to locate a piece of inconel
tube/pipe or at
> least 321SS
> > pipe. I'm getting tired of building mufflers only to
have them
> > self-destruct in a few hours. From what I can
tell, the
> Wagner tubes
> > are holding up. I hadn't considered using a larger
diameter
> > "handrail"
> > to fabricate a tangential muffler. I'll check
into that.
> >
> > Mark
> >
> > P.S. My tig welder is broken. ;-(
> >
> >
> > Too bad. That is bad news. I am sure Jerry will weld
something up
> > for you.
> >
> > Some heavy duty sheet metal shops can roll up 304 SS
into a large
> > tube or perhaps
> > two 180 degree sections of large tube. Same goes for
Inconel
> sheet.
> >
> > 0.065" 304 SS would probably work but .090" would
work for
> sure. I
> > don't
> > thing Wagner has hand rail in eight or ten inch in
diameter.
> >
> > Paul Lamar ...No rotor no motor.
> >
> > You could do a spin tec type muffler or maybe use rock
wool or
> > steel wool instulation type packing.
> >
> > Clifton
> >
> > That stuff goes away immediately :) The best plan is
put nothing
> > in the muffler. Parts inside the muffler glow
white hot.
> > You can stand behind this airplane and look down the
exhaust
> > pipe and into the muffler when it is running. Even
metal parts
> > are melted and spit out if they are too thin.
> >
> > My 182 O-470 will (and has) spit parts out of the
muffler
> eventually.
> > These are high continuous HP engines not at all
related to
> > car engines.
> >
> > Paul Lamar ...No rotor no motor.
>
> All the tangential I have made have been .065 321. I can
buy sheet
> and roll the canister. I can't remember where I bought
the 2" o.d.
> tubing, maybe Burns Stainless.
> I have not made one in a couple of years. Jerry
>
>
> Go to the spin tec it has been installed on rotaries it
is some what
> costly
> thought on the plus side people have made their own
version at great
> cost savings .
>
> Clifton
>
> I think Tracy destroyed one of those too. Auto mufflers
are just
> not up
> to it. Perhaps one could copy the Spin Tech using thicker
material.
> --
> Paul Lamar ...No rotor no motor.
>
> If so news to me Tracy had a spin tec; it worked well
for him
> but he wanted to explore a less exspensive option.
I forgot
> what he's flying now but it could have been that his less
exsp
> muffler didn't hold up over the long run .
>
> Clifton
>
>
> Paul,
> What I recall is that the Spin Tech worked well, but it was
square which
> caused high drag. The Hushpower II is bullet-shaped and
therefore much
> lower drag. I would be willing to try a Spin Tech if I could
fit it
> inside the cowl.
>
> Mark
>
> I think it might fit. Do you have the dimensions or can
get them.
> I can do a 3D. One problem may be it won't handle 300 HP.
> Check the inlet pipe size. What size is your down pipe?
>
> Paul Lamar ...No rotor no motor.
> Paul,
>
> Sorry, I don't have a Spin Tech muffler to measure. I'm sure I
could
> fit it inside the cowl, but it would require a new exhaust
system as
> mine is pointing down and back. My most recent effort included a
custom
> ball joint with 3" inlet and a 2.5" outlet. I'll look today to
see if I
> have room for a 180* bend. If so, I could possibly make it
fit along
> side the exhaust.
>
> Mark
They should give you the dimensions if you contact them.
Paul Lamar ...No rotor no motor.
I flew for about 30 minutes again today after about a month of working
on a list of nuisance items. The HP2 has gotten a little louder,
although the exhaust note is more pleasant to the ear than the original
spiral-flow muffler. The HP2's insulation began to melt about 15
minutes after shutdown, same as after the last flight. I made sure to
keep the EGT's at or below 1600. Strange...
Mark
Just let it purge itself. If the housing does not melt you are ahead
of the game.
Paul Lamar
My thoughts exactly...
Mark
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