|
Actually, Mark, I really favor the noise
cancellation approach - much more elegant - however, I figured you did not want
to tow a WWII type glider behind you with the support apparatus
{:>).
Seriously, the cut out approach would tame the beast on
the ground - except for the short duration during your take off roll when you
are hopefully further away from hangars and ear drums. On landing, you
probably won't be applying full power so the beast will be further way and
airborne or even if you need to turn on the muffler during landing approach -
shouldn't be too bad as you (hopefully) won't need anything like full
power.
But, seriously if you are considering adding a turbo
remember that ALL turbo installations create more back pressure than just about
any muffler. True you do get some power back with the additional
combustible mixture which creates even more back pressure, etc. Not to
mention the 50-80 lbs of additional weight with turbo, exhaust controller, oil
lines, turbo header, coolant lines and intercooler and the possible need to have
an oil scavenging pump to get the oil back to the pan from the
turbo.
But, Hey, don't let me persuade you differently by talking
you into a 2 lb cut-out vs 80 lbs and $3500 for a turbo installation
{:>)
Ed
Sent: Wednesday, November 24, 2010 2:09 PM
Subject: [FlyRotary] Re: Exhaust Cut-out was [FlyRotary] Re: Friends
and Family....
Ed,
You ought to be ashamed to even suggest such a thing! I would have
thought that an EE would come up with a more elaborate "electronic"
solution, such as a noise amplitude attenuation/cancellation/suppression
system (NAACS), sort of like a giant ANR headset that fits over the
tailpipe. The whole system would consist of one IC and a big
speaker. You could spend the next ten years developing it for TSO
market.
On second thought, a cutout would be a great solution, except that it kills
power where you need it the most. I may have to add a turbo-charger just
to quiet the savage beast!
Mark
On Wed, Nov 24, 2010 at 12:11 PM, Ed Anderson <eanderson@carolina.rr.com>
wrote:
Hi Mark, Chris and the rest - Happy Thanksgiving -
except for scrooge Chris of course {:>)
Mark, been thinking about your exhaust conundrum -
clearly the least exhaust back pressure is best for performance out of your PP
- however, as you have indicated the Wail of an unmuffered 20B PP
port might force you to get towed to 10,000 MSL before
turning on the engine to comply with noise abatement rules. Not a very
viable solution.
Got me to thinking about a similar problem back in the
Hot rod days. The solution was the "cut-out" - simply a valve in the
exhaust system that diverted the exhaust through the muffler when the sound
police were in near vicinity - and then when all was safe (like Chris not
being around {:>)), the valve was switched to divert the exhaust down a
straight pipe.
I'm wonder whether that might not be a viable solution
to having your cake and eating it also? For most of us running stock or
mild street ports - its probably not worth the effort, but in you case it
might be.
Here is a URL to cut-outs both mechanically and
electrically activated
Ed
Sent: Wednesday, November 24, 2010 11:51 AM
Subject: [FlyRotary] Re: Friends and Family....
Chris,
Well, you can always go out to the airport and polish your turbo while
you wait for your EC-2 to arrive. ;-)
If weather permits (and I get caught up on the "honey-do's") I may
venture down your way this weekend. But before I fly again, I've got to
get the EGT's hooked up after changing exhaust system. No need for
me to call, you'll be able to hear me doing my runup at 50R. That
will give you about a 45 minute warning. Are you planning to be at
the airport Saturday or Sunday?
Seriously, I'll call you in advance. How do I find your hangar once
on the ground? From the YouTube videos, it appears that you've got more
hangers at Ellington than Col. Sanders has chicken coops. I'll need a
road map to find your hangar.
Mark
On Wed, Nov 24, 2010 at 10:29 AM, Chris Barber <cbarber@texasattorney.net> wrote:
FINE, I guess it is obvious that a holiday that focuses on friends and
family is more important than tending to your aviation project and posting
your progress , discoveries and insight here. NO PROBLEM.
We see where your loyalties lie and it is certainly NOT helping
satisfy my 'fix" of rotary knowledge, otherwise the silence would not be
as deafening as
an un-muffled 20b at full
song.
Go ahead, eat your turkey, watch the Cowboys get beat, fall asleep with
that evening cocktail dangling from your hand. I can wait.......
I will be thinking of you all as I "serve and protect" while other officers,
as well as all of you, enjoy the day with their families. I will
be checking the list with disappointment as no new emails get
posted. Heavy sigh.
Oh, and Happy Thanksgiving. ;-)
Chris Barber
Houston
|