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From: "George Lendich" <lendich@optusnet.com.au>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-3541992@logan.com>
Subject: Re: [FlyRotary] Re: Ground Testing
Date: Wed, 11 Mar 2009 07:17:56 +1000
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Ed,
Speaking of velocity etc, I had a thought about how to better manage the 
P-port. My idea is a duel inlet system with a Siamesed inlet port.
The duel inlet system would have one small primary runner and one larger 
secondary runner.
The inlet port would be round but split in two, an upper portion and a lower 
portion.

The carbs or injectors would be staged.

Of course this is not dissimilar to the conventional Mazda intake system in 
using carbs and side inlets, but would be new for PP and eliminate some of 
the PP problems, like poor idle.
What do you think?
George ( down under)
> Hi Dave,
>
> The induction and exhaust system of any engine plays a (the?) major role 
> in
> producing good power.  When I first started flying with an 86 N/A 13B 
> using
> a "Racers' induction" system, I was probably not producing over 130 HP on 
> a
> good day.  After developing a bit better understanding of induction 
> systems
> match with engine operating regime, I ditched the "Racers" induction 
> system
> and build one of my own.
>
> I now consistently and reliably produce 175-185 HP on take off.  I turn a
> fairly large prop 74x88 and get 6000-6200 static rpm with a fuel flow of
> from 17.5 to 20 gph (depending at least partly on OAT).  A key factor in
> producing good power is to match your operating rpm and induction system
> parameters  - that was my failing early on.
>
> I had a undoubtedly good 9000+rpm induction system (I mean the rotary 
> racers
> were using it successfully),  but I was only turning 5200-5500 rpm on take
> off.  So the induction system best operating region was poorly match to my
> operating regime (or vice versa).  It simply was not producing the 
> air/fuel
> mixture velocity at that rpm needed for good "stuffing" of the combustion
> chambers.
>
> After I got rid of the short large diameter induction system and switched 
> to
> a set of longer, smaller diameter runners, power increased remarkably. 
> One
> reason is, of course, the lower operating rpm I desired maximum power at 
> (I
> designed my system for max power at take off)  needed a smaller diameter 
> set
> of induction tubes to create and maintain good runner mixture velocity.
>
> So, while the Renesis is capable of producing more power than the older 
> 13B
> out of the box, you will fail to achieve this potential if your induction
> and exhaust system are not well matched to your operating regime.  For
> example, the 6 port Renesis can wind to 9000 rpm in the automobile
> installation producing gobs of HP.  However, in aircraft use a more likely
> top end is 7500 rpm (that's the limit listed for the 4 port Renesis.)  For
> that reason, I would opt for the 4 port over the six port Renesis, as  the
> six port is really not going to buy you much (in aircraft usage) except 
> more
> difficult in trying to build a six port induction system rather than a 4
> port.  Just my opinion, of course.
>
> I do not plan on putting Renesis in my aircraft simply because it would
> really not buy me anything over the older 13B (other than perhaps more
> available parts) because my induction system is tuned for max power at 
> 6000
> rpm (take off).  I don't fly at max power in cruise so there was no reason
> for me to tune for max power at 6800 rpm (my max rpm).  So design your
> system for the operating regime you most want the power.  Some folks want 
> it
> at WOT in cruise, as for myself - getting in and out of small grass 
> strips,
> I wanted the power at take off. Therefore, the next rotary I hope to put 
> in
> my bird with be the new developmental engine the 16X.  Hopefully it will 
> be
> out in the 2011 model year.
>
> Your mileage may vary.
>
> Ed
>
> Ed Anderson
>
> Rv-6A N494BW Rotary Powered
>
> Matthews, NC
>
> eanderson@carolina.rr.com
>
> http://www.andersonee.com
>
> http://www.dmack.net/mazda/index.html
>
> http://www.flyrotary.com/
>
> http://members.cox.net/rogersda/rotary/configs.htm#N494BW
>
> http://www.rotaryaviation.com/Rotorhead%20Truth.htm
>
> -----Original Message-----
> From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On
> Behalf Of Dave Wilenius
> Sent: Tuesday, March 10, 2009 9:54 AM
> To: Rotary motors in aircraft
> Subject: [FlyRotary] Re: Ground Testing
>
>
> "A normally aspired Renesis will work well, but I think will need very
> careful attention to intake and exhaust optimization to get the power
> you're probably hoping for."
>
> This seems to go against what I thought was conventional wisdom where the
> Renesis is lighter and doesn't have the same level of exhaust bark, making
> it a good choice. If you want between 180-200 hp is this really that
> difficult?
>
> I was also under the impression that the placement of the exhaust ports on
> the side
> housings improved fuel efficiency.
>
> If you design goal was fuel economy with 180hp would you still opt for a
> turbo REW?
>
> regards,
>
> Dave
>
> -----Original Message-----
> From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]On
> Behalf Of John Slade
> Sent: 2009-03-09 01:20
> To: Rotary motors in aircraft
> Subject: [FlyRotary] Re: Ground Testing
>
>
> Welcome, Jim.
> You will get differing answers to that question. Mine is "not much
> beyond the integrity of the engine itself".
>
> Installation of a rotary in a Cozy is fairly tight and, by the way, in
> my opinion a 20b is a little too big, long and heavy. Apart from test
> running the engine to be sure that it's been correctly rebuilt, most of
> what you do on a test stand will be a waste of time and effort. When
> installed on the plane the engine is dependent on many systems that
> either can't be effectively duplicated on a test stand, or will have to
> be re-engineered when installed in the plane.  Sure, if you can get your
> hands on a dyno you can test power and tune, but once you put the engine
> on the plane you'll have to wire the engine into the plane's systems and
> implement fuel, ignition, injection, cooling and exhaust systems that
> fit in the cowl. Testing those systems in the "real world" is really
> only possible with air flowing through (and over) the cowl into a prop
> at 200 mph and at various attitudes.
>
> A normally aspired Renesis will work well, but I think will need very
> careful attention to intake and exhaust optimization to get the power
> you're probably hoping for. Next you will need some sort of muffler that
> can hold up. I wasn't keen on hanging a muffler below the fuselage like
> the RV guys do. There isn't much room for that in a Cozy and it would
> look very ugly and draggy. Putting a red hot muffler inside the cowl is
> a heat radiation problem, plus there's very little room. A turbo is
> relatively small, circular and easily screened for heat. My approach was
> that the easiest way to silence the roar was to install a turbo. This
> way you don't have to bother with an exhaust system, and the intake
> system is much less critical. This gives added (and exciting) benefits
> in take-off and cruise power, but comes with its own complexity. The
> trick seems to be to use the right turbo. Then, if you use a turbo, the
> Renesis is a little high in compression ratio and you might be better
> with a 3rd generation 13B. I'm working with another builder right now on
> his Cozy project. We are duplicating my 13B exactly. That might be a
> useful indication of whether I consider it a success. The Cozy Girrrls
> are very knowledgeable on this rotary stuff,  and they also are
> installing a 3rd gen 13B with a big turbo.
>
> In general, I'd say the rotary is more risky to start with - say the
> first 50 hours - because every installation is different and errors WILL
> occur. After the first 50 hours I think the rotary is well worth it.
> It's safer, faster, quieter, very much smoother, and much cheaper to
> maintain. The devil is in the peripherals. Redundancy is key. I have
> redundant fuel tanks, filters, pumps, injectors, plugs, ignition
> computers, batteries. Failure of any item is survivable because I have a
> spare. The problem is that redundancy breeds complexity - this is where
> the extra build and testing time comes from. I'd recommend the IVO
> in-flight adjustable prop.
>
> I've seen too many failed rebuilds by people who have much more
> experience and talent than I, to risk applying my skills to this most
> critical part. Also, there's enough to do with the peripherals and I
> didn't need the learning curve. Unless you're determined to rebuild your
> own you might consider using an expert who's done it 1000 times and
> knows what to modify for aviation build your engine. Given your
> investment in the plane, a professionally rebuilt engine is cheap
> insurance. Instead, I'd suggest concentrating your effort on getting the
> peripherals perfect, adding redundancy everywhere you can get it.
>
> Having said all this, my take, for what its worth, would be to forget
> the engine for a while and spend every spare waking moment building
> yourself an airframe. Given that you have a few years to make the engine
> decision, use those years to see what happens with other installations.
>
> I hope this helps in your decision process, or at least starts yet
> another heated discussion you can learn from :).
> Regards,
> John Slade
> Turbo Rotary Cozy, N96PM.
> 98 hours and purring like a kitten.
>
>
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