John is correct, George.

 

An engine does not really care how the combustion pressures inside the chamber are achieved (if fact - it don’t even know {:>).  You can achieve high camber pressure by using high compression pistons and low boost or low compression pistons and high boost to get the same combustion chamber pressures.  IF you are running very high boost then low compression pistons/rotors may be in order.

 

One of the advantages of using normal or even high compression pistons/rotors is that you get immediate response and less of a turbo lag.  Also since you are using less boost there is less exhaust  back pressure and the turbo does not have to work as hard. You are less likely to encounter compressor surge at high altitude using low boost, etc.

 

 Regardless  how you go about it, the key element is control of the combustion chamber pressures within limits.  As long as you don’t exceed that you are not likely to  get into detonation or other bad things.

 

Now when installing a turbo in a passenger car where the driver may not have a clue about these things, then the manufacture will err on the side of caution and put low compression pistons in to prevent someone from blowing the engine (as readily).   I have turbocharged cars and have managed to shear the ring lan off the pistons due to over zealous application of boost {:>)

 

My $0.02

 

>All turbo 13B's require low compression rotors.
Not quite true, George. On the advice of two trusted rotary experts (one of whom was Leon Promet - remember him?), mine has the 9.7 rotors and 3mm seals. Leon said this just gets you a free 30HP so long as you don't overboost and you keep the timing & mixture in range. I don't have any detonation problems boosting to 42 MAP with the IVO prop. I did notice some detonation / pre-ignition noises early on when running up with a fixed pitch prop. These went away immediately on throttle back and didn't do any engine damage.
John Slade


George Lendich wrote:

In Chile there are only a few Rotaries. Mazda sell a lot of cars here, but not too many rotaries, and there are no enthusiasts of the wankel engine,  so for support and parts, I’ll have to go to the U.S. anyway.

 

If I chose and engine, a two rotor, which way do you think is better, the 2004 renesis for example (I saw one in eBay) or the 89-91 or 93-95 as you said? Can the “modern” renesis be use with a turbo?

 

Thanks

 

Gonzalo.

 

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of William Wilson
Sent: Domingo, 23 de Agosto de 2009 1:29
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Three or two?

 

With only a couple of exceptions the two- and three- rotor engines take the same parts.  Only the "big" center housing and the eccentric shaft are really special for the 3-rotor engine.  Luckily, these don't usually need to be replaced.  Of course, the manifolds, fuel injection and most of the electronics are unique but you won't use the stock parts anyway.  Most everything else is either the same as, or interchangeable with, the '89-'91 or '93-'95 13B turbo.

Which, of course, brings up the question of whether or not you can get *those* parts.  There is plenty of support in the U.S. for rotary engines, since Mazda sold lots of RX cars and tuners are used to bringing in Japan-market parts.  Is there such support in Chile?  It is tough enough to build a plane without having to build your own engine too.

2009/8/22 Gonzalo A. Giménez Celis <gonza@gimenez.cl>

Well, actually is not that bad. There are a couple of runways 3000 ft long,
and others 2000 ft. Altitudes varies from sea level up to 7500 ft, but I
don't plan to go there often, and if I do, the runway is very long. I want
to have a little more power just in case. I think the 200 HP is enough,
right?

Also, what about the parts, it seems that the two rotor parts are much more
available than for the 20B...

Thanks!!

Gonzalo

-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On

Behalf Of Dave
Sent: Sábado, 22 de Agosto de 2009 17:08
To: Rotary motors in aircraft

Subject: [FlyRotary] Re: Three or two?

While I am in favor of the rotary, it is worth saying that none of the
very few currently flying turbo rotaries have had trouble free
installations.

I know of John Slade and Dave Leonard, and both have had more than one
turbo failure in the process of finding what works.

I do not know if Mistral is currently selling its turbo version.

What sort of runway length and density altitude are we talking about,
where you intend to operate?
Dave

Thomas Mann wrote:
>
> A two rotor engine produce close to 200 hp at 291 LBS (132 KGS)
>
> A two rotor with turbo can produce 230 hp at 328 LBS (149 KGS)
>
> A three rotor engine can produce 300hp at 390 LBS (177 KGS)
>
> *From:* Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]
> *On Behalf Of *Gonzalo A. Giménez Celis
> *Sent:* Saturday, August 22, 2009 3:05 PM
> *To:* Rotary motors in aircraft
> *Subject:* [FlyRotary] Three or two?
>
> Hi group. As I told in previous questions, I’m building a Cozy MK IV,
> and I like the Rotary idea. I would like to have between 200 and 250
> HP, since in Chile we don’t have such long runways like in the U.S.
> and is a pretty mountainous country. Regarding this, which way is
> better, a three or two rotor engine? Is the three rotor too heavy? Can
> I use a turbo in a two rotor engine without affecting reliability and
> weight? Etc…
>
> Thanks.
>
> Gonzalo
>
> Chile
>


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