Where can someone get a 20 b motor????

On Sun, Aug 14, 2011 at 4:12 PM, Tracy <rwstracy@gmail.com> wrote:

Got the coils changed out from RX-8s to a mixture of LS2 and LS1 coils and installed in an improved air box.   Coils much cooler now.

Ran with auto pilot on to hold altitude steady during tests so I think they are pretty accurate.  I was mainly interested in fuel economy and speed at various fuel flows.   All these results were at 14,000 feet.  I'll do some at 18,000 where the results should look even better next time.  I forgot to dress warmer because the temp on ground was 94 F.   OAT during test was 39F.  Speeds are TAS.  

6.0 GPH   169 mph.  28.1 mpg

7.0 GPH.   180 mph.  25.7 mpg

8.0. GPH.   200 mph. 25 mpg

10.0 GPH.  224 mph. 22.4 mpg

The manifold pressures sounded a bit unrealistic during test but 2 different instruments agreed so I think they are right.   The only one I wrote down was at 7 GPH where it was at 13.9" Hg and rpm was 5174.   The sweet spot seems to be very close to 8.0 GPH.   I think that is where the rpm gets into the area where the fuel charge is stratified by the centrifugal force at around 5400 rpm and the mixture can be aggressively leaned.

The goal is to get 30 mpg at 200 MPH at 18000 ft.  If I can get there I can fly non stop from FL to CO with only a small aux fuel tank.

Tracy

Sent from my iPad

On Aug 14, 2011, at 1:41 PM, Charlie England <ceengland@bellsouth.net> wrote:

Who's flying one (P-ported *Renesis*), & does it meet *both* criteria?

Clarification: If I read correctly, the question was about complex intake vs adding a supercharger & using it to 'normalize' only back to the output of a properly done intake. My point is that a manifold like Tracy's is very simple to build (much simpler than anything for an aftermarket supercharger), and the power (and efficiency) is there with much less weight & much higher reliability. Higher *output* & high altitude benefits are still there, but that wasn't the question.

Obviously, after the P-port is done the intake is simpler (by 2 tubes), but not that many homebuilders have the resources to do the P-port mod, which makes the manifold look like child's play.

Charlie

On 08/14/2011 10:02 AM, Mark Steitle wrote:

Charlie,  

Maybe you meant "...best power of all side ported rotaries".  I'm pretty sure that a p-ported 13B would easily produce more power than a side port motor, assuming they do a good job on the intake and exhaust.  The nice thing about a p-port motor is the intake is simpler and easier to build than a side port intake.  

Mark S.

On Sun, Aug 14, 2011 at 8:34 AM, Charlie England <ceengland@bellsouth.net> wrote:

On the subject of Renesis intake complexity, take a look at Tracy's intake (pic from his web site).

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http://www.rotaryaviation.com/renesis_engine.htm

Can't get much simpler, & as far as I know, he has the best power numbers and the best efficiency numbers of anyone flying. His intake tubes are now longer than in this shot, but as you can see from the pic, adjusting tube length (retuning) is pretty straightforward.

Charlie




On 08/14/2011 06:36 AM, Ed Anderson wrote:

Sam, As you find in this "hobby" there  are always trade offs.  First, technically there is no reason you could not do what you propose - however, you will add weight and complexity.  A poor intake affects both N/A and forced induction - its just with forced induction you are paying in a different way to overcome any defficiencies in your intake. 

 

 If going that route, I personally would prefer the centrifugal type belt/gear driven blower over the roots type which has historically had the poorest efficiency.  On the other hand, if you are not going to "boost" above ambient pressure - then I think I would concentrate on getting a good N/A intake.

 

Good luck on your project whichever decision/approach you take.  Super and Turbo chargers have both been used successfully.

 

just my $0.02\

 

Ed

From: Samuel Treffinger

Sent: Sunday, August 14, 2011 1:01 AM

To: Rotary motors in aircraft

Subject: [FlyRotary] Renesis Question

I think my brain has had a meltdown: I am thinking about "supernormalizing" the Renesis engine. Is this even possible. The idea is to use a by-passable positive displacement type blower (roots type...probably an eaton m90) fed to an intercooler that then sends air to the engine. If my thinking is correct, and it probably isn't, this would eliminate the complex N/A intake, while not over-boosting the Renesis engine. Also, the supercharger being a positive displacement blower would in theory produce more boost than is needed by the engine at all rpm levels, eliminating the "peeky" torque of boosted engines. The excess (above standard intake) pressure would be controlled via an automatic or manual waste-gate. Please shoot my idea down if it is insane, but i would like some constructive criticism if it is available.

Sam