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Oh yeah, one more thing: fuel. Where will you put it, & if you
find a place, do you intend to fly only solo? If you're making a
full 200 hp at cruise, you'll be burning at least 17-18 gal per
hour, probably closer to 20 gph. A LOT more than that in climb, if
you use the turbo's HP.IIRC, leading edge tanks on a M-II hold
somewhere between 35-40 gal. The header tank will hold around 29
gal, but reduces payload. There will be serious gross weight issues
if you carry more than 1 1/2 hrs of fuel + 2 people + baggage.
FWIW...
On 2/17/2011 8:04 AM, Charlie England wrote:
I'll be the wet blanket.
You said your airframe is a Mustang-II. The largest practical HP
the airframe is designed to handle is around 200 (actually less
than that). How short is your runway? 200 hp with a controllable
prop should get you off the ground in 500 ft, at worst. How high
do you need to fly, & how fast do you reasonably expect to go?
M-II's with slightly over 200 hp normally aspirated Lycs, if built
'clean' & reasonably light, can cruise at or over design VNE.
Flying high, with lower indicated airspeed, will not protect from
flutter (death).
A properly tuned Renesis will make a bit over 200 hp. Is there a
reason for desiring more, other than bragging rights?
Charlie
On 2/17/2011 6:31 AM, Dustin Lobner wrote:
Bill,
I'm expecting 10 years to build, hoping for 7. I understand
that part. I also understand fabricating the intake, I looked
at pictures of the stock mazda engine and my face basically went
o.O
The compression ratio I might have lowered just to prevent
detonation. I'm going to have the engine tweaked by a
professional engine builder of good reputation before I use it,
this may be one of the things done to it.
You say below you have two speeds, takeoff and cruise. I guess
my thought is to use the aux valve and the ECU's ability to turn
it on and off to allow tweaking of cruise and takeoff moreso
than you otherwise could. One nice thing about this is that I
have free dyno time to sort this all out.
Dustin
On Wed, Feb 16, 2011 at 11:32 PM, Bill
Bradburry <bbradburry@bellsouth.net>
wrote:
Hi Dustin,
Dreaming is good. There are
a lot more dreamers on this site than there are
fliers! You are going to fit in quite well.
The reason for all those
valves and plumbing on the Renesis is that it is
normally aspirated. They don’t make a turbo for
it. It has 10:1 compression so you need to take
that into consideration when you boost it. You
could blow it up. Also with the plane, unlike the
car, you basically have two speeds, take off and
cruise. You don’t need to try and maximize the
intake for all those different rpms because you
will only be running at, mostly, two of them. The
intake that comes from the factory will not fit
under the cowl on a plane. This means you will
have to build your own. If you start trying to do
all the plumbing and valve flipping that you are
talking about, you will certainly need a bunch of
friends with lots and lots of EEEEs behind their
name.
You would be surprised at the
journey that this becomes. I started working on
my plane in 2002 and it just passed its
Airworthiness Inspection. I still haven’t flown
it because there are still issues that need to be
tweeked. Maybe next week!
Good Luck!
Bill B N249B
From: Rotary motors in
aircraft [mailto:flyrotary@lancaironline.net]
On Behalf Of
Dustin Lobner
Sent:
Wednesday, February 16, 2011 10:39 PM
To:
Rotary motors in aircraft
Subject:
[FlyRotary] - Day dreaming...
Hi everyone,
I posted this today on the HomeBuiltAirplanes
forum. Going to C/P it here for
comments/questions/flaming.
Background, I'm planning on building up a
Renesis with a Turbonetics turbo, putting it
into a Mustang II. I'm planning on using
MegaSquirt 3 (or whatever is available when I
get there) ECUs. These ECUs control things like
waste gate management, any servos you want, in
addition to the the EFI and ignition.
So... <copy-paste from the forum>
The Renesis has 6 intake ports (I think a 4 port
model was made for awhile, but I'm going to buy
a crate engine so that's out). I found a white
paper somewhere, written by the designers of the
Renesis, talking about each port. There's the
primary, which is always open. Secondary comes
on 3,500-4K RPMs-ish. Aux turns on at 7.5K RPMs.
The ECU I'll be using has outputs for
controlling things like butterfly valves for
different intake runners.
My understanding is that most people simply run
on the pri/secondary only and plug the aux, or
run with them all going. Seeing as how I'll have
an ECU to do some work if I want, what do people
think about valving either the aux or the
secondary and aux? The ECU is flexible regarding
mixtures and whatnot, so I'm thinking I could
tune the "cruise" setting for 6K RPMs, aux
closed, and then tune the "max power" setting
for 7k RPMs with the butterfly opening at 6800
or something. Wastegate (should I go with a
turbo) can vary by RPM too, so I could have it
set for "normalize" 6800 and below, and "boost
the heck out of it" above that.
*Shrugs* I know, it's an airplane, KISS. I have
a few years before I'll be to the point of being
able to wrench on the engine, so I'm dreaming
about it now and hashing things out now so that
when the engine gets here I can just build.
>From discussions on the Mazda list,
different length runners DO matter quite a bit,
so it's not like this is a completely worthless
thought.
Thinking about it, valving the secondary seems a
bit stupid, because if that valve breaks you
don't have a good portion of your power, whereas
if you lose the aux it's not the end of the
world.
<end paste>
I guess what I'm going for is, I remember
some conversation here about different length
runners for different tuning. This could let
you have the best of both worlds...thoughts?
And mind you, I have a two engineer aviation
minded friends, one with a ME/EE double and one
with an AeroE, so I'm not completely without
help designing this.
Dustin
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