On 30 Aug 2022, at 7:55 pm, Mark McClure mark.mcclure.m3@gmail.com <flyrotary@lancaironline.net> wrote:

@Charlie: I think all 4 injectors being the same makes sense.
@Steve: Your Glasair looks great! How does she fly?

"Simplicity is the answer - don’t want to reinvent the wheel”

With that in mind - I may program up my EC3 and EM3 as I own them already and MegaSquirt is expensive and Speeduino seemingly is out of stock and has been for a while.

I have heard from Ross as well that SDS will not support Rotary, but I am not entirely sure I understand why as it is intended to be fully user programmable why would I not be able to program it to work on a rotary just like I would be able to program the MS Pro or Speeduino?  Benefit being SDS is supported and designed for aviation.

What am I missing?  

To understand how a rotary engine works with MegaSquirt^® EFI Controller, we need to figure out how MegaSquirt^® will 'see' the rotary in terms of injection cycles.

In 720° of crank rotation, a four-stroke cycle piston engine (two revolutions = 4 strokes) ingests its rated displacement (ignoring volumetric efficiency issues and the like) of air. In the same 720°, the rotary swallows twice its rated displacement (somewhat like a 2 stroke cycle engine).

To understand this, recall that a Wankel rotary engine has three faces on each rotor, evenly spaced at 120° apart. The rotors rotate at ¹/₃ the eccentric shaft speed, so we see an ignition event every 120°Ã—3 = 360 degrees, and all three faces require 3×360° = 1080° of eccentric shaft rotation.

(Note that all of these factors are determined by the geometry of the case, housing, and gears, and are the same for all Wankel rotary engines.)

In the 13B, there are two rotors, however, and they are phased 180° apart, giving an ignition event every 180°, alternating between the rotors.

Crank Degrees	Piston Engine Cylinder Firing	Wankel Rotor Firing
0°	1	1 (face 1)
180°	3	2 (face 1)
360°	4	1 (face 2)
540°	2	2 (face 2)
720°	1 - back where we started	1 (face 3)
900°	3	2 (face 3)
1080°	4	1 (face 1) - back where we started

So to MegaSquirt^® EFI Controller, the Mazda 13B rotary looks just like a 4 cylinder engine, except for having a 2nd set of plugs delayed by a few degrees. Each rotor has 3 chambers and executes an Otto cycle (intake-compression-power-exhaust) in 1080° of eccentric shaft rotation.

Therefore, setting up a rotary as a 4 stroke cycle, 4-cylinder (since it gives 4 tach pulses per 720°), and 2600cc (displacement x 2), works out fine. The number of squirts per cycle may need some experimentation for your specific installation, as with any MegaSquirt^® installation.

On Mon, Aug 29, 2022 at 2:19 PM Le Roux Breytenbach breytenbachleroux@gmail.com <flyrotary@lancaironline.net> wrote:

Mark: I am going for the Mercury 2 by Spittronics in South Africa.They support the software for the rotary wankel engine.

https://spitronics.com/

Think that they have sorted out the problems over the years.

Simplicity is the answer - don’t want to “reinvent the wheel” lot of guys in racing uses the software in the wankel engins.

Regards

Sent from my iPhone

Le Roux Breytenbach 

On 29 Aug 2022, at 18:31, bruce buksyk bbuksyk@outlook.com <flyrotary@lancaironline.net> wrote:



Great questions…  I too would like to start back up.   In the previous thread, there was mention of SDS EFI. I’ve been in touch with Ross at SDS and they no longer produce systems for Wankels due to low numbers.   FYI..

 

Sent from Mail for Windows

 

From: Mark McClure mark.mcclure.m3@gmail.com
Sent: Monday, August 29, 2022 10:45 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Resurrecting my project

 

So after a few years hiatus of working on the project, I am back at it.

Glasair Super 2 with 4 port RENESIS.

 

Feels good, except I cannot remember all of my plans, nor some of the decisions I made. 2 sets of bell mouths for the intake, obviously one was first… and one was “decided on”

 

I purchased my EC-3 back in 2012. I believe at the time I asked Tracy for RENESIS engine with stock injectors and LS1 coils. Searching through the archives, it seems Finn Lassen found that the EC3 is not programmed correctly to represent that? Or maybe I misread it.

 

All my electronic pieces are still unopened and no work has really been started on installing any of it. I am working on getting all the ancillary systems such as intake, exhaust, oil and cooling setup. 

 

So a few questions for the group:

1) ditch the EC3 and EM3 altogether (and provide it to someone else as a backup) Start acquiring/learning SpeedUino or some other system?

2) continue with what I have (is there some way to validate or change the programming of the EC3?)

3) unrelated: Anyone made the swap to yellow and blue injectors for RENESIS and are happy with their decision? Or stick with red and blue?

 

Appreciate any insights from others' experiences as I get back at this. 

 

Warm regards,

Mark McClure

 

60% Glasair Super 2TD

35% 13b