Need a box shaped nosebowl

[DonMorrisey]

I have an experimental Bushcaddy with a Lyc O-235. I also have the
standard ACS nosebowl for a lyc: http://www.aircraftspruce.com/catalog/appages/mc3a.php

My exhaust is a slightly modified Powerflow system. I have just
discovered I can't use my nosebowl because it is too rounded on the
bottom. The top is fine but the bottom is basically a crescent shape
from side to side. To accomodate the exhaust pipes and collector box
from the powerflow sytem I need something with a more rectangular or
boxy shape on the bottom. As an example a powerflow system will fit
in a Glastar Sportsman but their colw costs $1200. Any thoughts or
ideas??? Any kits you can think of that have such a shape to the
noebowl where perhaps I could buy that component??

Thanks. Don...

[Bob Kuykendall]

On Feb 4, 11:37*am, DonMorrisey > wrote:
> I have just discovered I can't use my nosebowl because it is too rounded on the
> bottom...

Does that mean you can't use the nosebowl, or does it just mean you
can't use it without modifying it?

I'd suggest considering just cutting away the offending portions and
installing one or more blister fairings as necessary to clear the
revised exhaust system.

[stol]

On Feb 4, 12:56*pm, Bob Kuykendall > wrote:
> On Feb 4, 11:37*am, DonMorrisey > wrote:
>
> > I have just discovered I can't use my nosebowl because it is too rounded on the
> > bottom...
>
> Does that mean you can't use the nosebowl, or does it just mean you
> can't use it without modifying it?
>
> I'd suggest considering just cutting away the offending portions and
> installing one or more blister fairings as necessary to clear the
> revised exhaust system.

I agree with this idea.. For sure the cheapest way and you will get
exactly what you need.

IMHO.

[DonMorrisey]

> > I'd suggest considering just cutting away the offending portions and
> > installing one or more blister fairings as necessary to clear the
> > revised exhaust system.
>
> I agree with this idea..


Howdy,
Where would I find these "blister fairings"??

Although I have a feeling the interference is too significant to cure
with those. Just giving it the eyeball test both lower left and right
sides would have to be cut from the nosebowl and somehow a boxier
shape created. I have never worked with fiberglass so really don't
want to undertake that unless absoluely necessary. Thre must be some
boxy type nosebowls out there...although I've been searching and
haven't found one so far. Thanks

[Bob Kuykendall]

On Feb 4, 12:30*pm, DonMorrisey > wrote:

> Howdy,
> Where would I find these "blister fairings"??...

You make them, using any of a wide variety of tools, materials, and
methods. My favorite method for small blisters is to constrain a nylon
or Visqueen membrane using double-sided tape and whatever else is
handy, inflate it with a few PSI of air, and lay up a few plies of
fiberglass over the resulting bulge. Fill to shape, file to fit, sand
smooth, and paint to hide.

> ...Although I have a feeling the interference is too significant to cure
> with those. *Just giving it the eyeball test both lower left and right
> sides would have to be cut from the nosebowl and somehow a boxier
> shape created...

Are we just talking about just the fiberglass MC-3 nosebowl here, or
are we talking about the nosebowl and lower cowl? I am hard-pressed to
see how any exhaust on an O-235 would get very far outside the
envelope of just the MC-3 bowl.

I suspect that what you might mean is that the exhaust system gets
outside the envelope of a lower cowl that would be formed by a ruled
surface extended between the lower half of the MC-3 nosebowl and the
firewall. Is that it, or am I off-base on that guess?

Looking at this picture of your engine, I can see that the PowerFlow
system is indeed a pretty tall exhaust system:

http://www.donsbushcaddy.com/sitebuildercontent/sitebuilderpictures/LycomingO235L2C.jpg

That's one of the reasons I was never a particular fan of the
PowerFlow. Their installations seems sort of clunky, and they have
that huge muffler hanging way out in the breeze. I'm far more partial
to the Vetterman systems common on the RV-series airplanes:

http://vettermanexhaust.com/

Thanks, Bob K.

[cavelamb[_2_]]

DonMorrisey wrote:
>>> I'd suggest considering just cutting away the offending portions and
>>> installing one or more blister fairings as necessary to clear the
>>> revised exhaust system.
>> I agree with this idea..
>
>
> Howdy,
> Where would I find these "blister fairings"??
>
> Although I have a feeling the interference is too significant to cure
> with those. Just giving it the eyeball test both lower left and right
> sides would have to be cut from the nosebowl and somehow a boxier
> shape created. I have never worked with fiberglass so really don't
> want to undertake that unless absoluely necessary. Thre must be some
> boxy type nosebowls out there...although I've been searching and
> haven't found one so far. Thanks

Well, the front part of the blister might be from a 2 or 3 liter Coke bottle.
I use Dr. Pepper bottles myself. The after part can be anything that makes
the shape you want. Wood, metal, plastic, bondo, plaster of paris, etc.

What's I'm recommending here is a male mold that the parts can be made on.

--

Richard Lamb
http://www.home.earthlink.net/~cavelamb/


"The clock of life is wound but once, and no man has the power
to tell just when the hands will stop, at late or early hour...
Now is the only time you own. Live, love, toil with a will.
Place no faith in time. For the clock may soon be still."

[Scott[_7_]]

DonMorrisey wrote:
>>> I'd suggest considering just cutting away the offending portions and
>>> installing one or more blister fairings as necessary to clear the
>>> revised exhaust system.
>> I agree with this idea..
>
>
> Howdy,
> Where would I find these "blister fairings"??
>
> Although I have a feeling the interference is too significant to cure
> with those. Just giving it the eyeball test both lower left and right
> sides would have to be cut from the nosebowl and somehow a boxier
> shape created. I have never worked with fiberglass so really don't
> want to undertake that unless absoluely necessary. Thre must be some
> boxy type nosebowls out there...although I've been searching and
> haven't found one so far. Thanks

Fiberglass work isn't terribly tough. It might be a bit itchy at times,
but it isn't THAT bad ;)

[DonMorrisey]

>
> I suspect that what you might mean is that the exhaust system gets
> outside the envelope of a lower cowl that would be formed by a ruled
> surface extended between the lower half of the MC-3 nosebowl and the
> firewall. Is that it, or am I off-base on that guess?

Bob,

The quote above is exactly the problem, hence the need for a more
rectangular nosebowl. So what I'm really after is direction on where
I may find a nosebowl that isn't crescent shaped on the bottom???

Thanks. Don...

[Bob Kuykendall]

On Feb 4, 5:02*pm, DonMorrisey > wrote:
> So what I'm really after is direction on where
> I may find a nosebowl that isn't crescent shaped on the bottom???

Ah, right. I'd start by looking at other airplanes that use that
particular model of exhaust system, and see what they use for a
cowling. It might be that the nose bowl of a PA-28 would fit, I seem
to recall it as pretty tall. If something like that doesn't work, you
will probably end up making an entire cowling, including nosebowl,
from scratch or nearly so.

Well, that's not actually what I'd do. I'd probably flog that exhaust
system on eBay and go with a different system that fits into a tighter
cowl. I just don't see the point in adding so extra frontal area and
volume to the cowling for an exhaust system with little if any benefit
over other systems available for experimental airplanes. But that's
just me.

Thanks again, Bob K.

[Bob Kuykendall]

On Feb 5, 5:30*pm, DonMorrisey > wrote:

> Well that's the great thing about experimental aviation, we can agree
> to disagree. *Powerflow Exhaust systems are proven to add
> considerable power...

I'd like to see a credible cite for that rather sweeping assertion.
The way I understand the situation, the PowerFlow exhaust restores
power detracted by the distinctly suboptimal exhaust installations
used in a variety of certificated airplanes such as PA-28, AA5B, and
C-172. Further, the system is STC'd so the installation paperwork is
minimal.

However, I don't think that there is any data to suggest that the
PowerFlow holds any measurable advantage over a Vetterman or similar
crossover system as found on a typical experimental airplane.

Thanks again, Bob K.