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Like all things in this "hobby" when you get something,
you generally give up something else. Tracy will be the first to tell you
that his new "log" type manifold gives him better top end power and speed, but
that he gave up some low end power and rate of climb with the Renesis in the
Rv-4.
Not to detract from his obviously well performing
manifold, but - The other thing to keep in mind is that Tracy is a
"Lightness" fanatic (well, perhaps too strong a descriptor - but, lets say
INTENSELY focused on making everything as light as possible), this translates
into very light aircraft with excellent weight/power ratio and low induced
drag.
Whenever we fly in formation he is always running 1 1/2 -
2 gallons/hour less burn rate. When we flew to Sun & Fun with Tracy in
his Rv-8, he maintained formation with the larger airframe with about 1 1/2
gallons less fuel burn than I ran in my 2 rotor Rv-6A..
Now that could just point out how heavy and draggy my
aircraft is - but, in my mind it clearly shows the importance of paying close
attention to weight. Tracy does not put anything FWF that he does not
carefully consider whether that is the lightest implementation he can come up
with - and it pays off.
But, when you can achieve 3750 fpm rate of climb
with that 3 rotor - who cares if the intake is perhaps not optimized for
rate of climb {:>)
Ed
Sent: Friday, April 22, 2011 4:22 PM
Subject: [FlyRotary] Re: FW: [FlyRotary] Improved performance of my
new (2009) intake manifold
That is my thought (and intention), also, at least for a
Renesis-based engine. Tracy seems to be making as much HP as anyone, & much
more than most. And his efficiency is *much* better than anyone else is quoting;
probably about as good as it's likely to get with a currently available rotary
powerplant. It would be harder to get any easier & simpler than four
straight tubes with bellmouths into a box with a throttle body.
For me,
at least, replacing that accessory housing is a whole 'nother level of
difficulty. :-)
Charlie
On 4/22/2011 12:29 PM, Rino wrote:
If you want simplicity and effectivity, look at
Tracy's intake manifold.
Rino Lacombe
----- Original Message -----
Sent: Thursday, April 21, 2011 5:53
PM
Subject: [FlyRotary] Re: FW:
[FlyRotary] Improved performance of my new (2009) intake manifold
Bill that is a pretty wild looking manifold! I can see that it was
intended to benifit from DIE? I've been leaning more towards a close fitting
'over the top' manifold
which would be usable for either pusher or tractor installs, however it
would be somewhat simpler than the pictured unit. It would take alot of
'study' and prep work to
get a cast unit in that configuration. More than likely it would need to
be hand fab'd and welded [same as what is pictured]. This is 'doable' but
the added cost of getting
all those parts together and into a working unit, would push the cost up
past the 'reasonable' level. At least as far as i can tell from a your
picture. Of course I could be seeing
more complexity there than actually exists. However, that being said I'm
open to all options and suggestions on how it could be made to work! :)
Best regards
Jarrett Johnson
www.innovention-tech.com
Jarrett,
If you want to
build an intake manifold, I suggest you build one that works well like the
one Dennis came up with or if he has a better idea now, try it.
See the attached
msg.
I believe that you
would have to build this for $500 or so to sell many and it would require at
least 3 iterations, 13B, Renesis, and 20B. I assume all the early 13B
intakes are the same???
Bill
B
From:
Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]
On Behalf Of Dennis
Havarlah
Sent: Wednesday,
November 10, 2010 3:27 PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Improved
performance of my new (2009) intake
manifold
As some of you know I started
flying my RV-7A with a cut - off Renesis intake manifold. In 2009 I
installed an new intake designed to route pressure waves from the
closing of rotor #1's intake into rotor #2 just before rotor #2's
intake closed. After using the new intake for over a year I am
still very happy with it's
performance.
I gained about 15 mph TAS at the
same altitude and manifold pressure
My static engine rpm increased
300 to 350 rpm.
My takeoffs are faster and
shorter with noticeable increase in
acceleration
My oil and water cooling is more
critical now because I make more HP.
But - I must confess I don't
believe the manifold can be reproduced economically. It's just too
complicated.
I also believe it should have
slightly shorter intake runners to increase the performance at higher
RPM. Decreasing the intake runner length probably would require
complete new geometry of the system.
I have another concept for
designing a Renesis intake that using a reflected wave from Rotor #1
returning to Rotor #1 .
I believe it would be much
easier to build and small enough to fit into the James rotorary cowl but
because my intake works well I am not moving ahead with completing the
design and building it.
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