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