13b rotary engine controllers. What are people using?


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Richard Schubert

Well-Known Member
Feb 5, 2009
Pittsburgh, PA
It's almost a given that for this application there is no perfect solution, I am just looking for a good compromise. Ross needs to step up and meet the market of dozens and get ignition into his rotary system. :bow:


Well-Known Member
Apr 1, 2011
Palm Bay Fl.
Heres what i dont get about this redundancy thing every aircraft person debates over.

When is last time you had a coil, cop, or coil near plug on an auto engine fail? If it does its just one cylinder. Its not like all the rest dont work either. Same with redundant injectors, again when is last time one failed in a car? And if you have individual egt you would start to see it running lean. Dual sensors, why? Aside from crank and cam the engine will run just not as good. Only sensors i see needing redundancy on is crank and cam. And running one coil per plug and no distributor.

Even sds has said not many even use the second ecu.

This redundancy topic comes up every time.
Haltech, motec are very well known renowned ecu's used in every form of controlling anything with an engine. They just dont fail. Things that fail are the non quality sensors used, the connectors, lack of strain relief and poor mounting. A rotary is not hard to make run and go with a newer system that supports it.

Its nothing more than staged injectors and staged ignition.

I know not common aircraft practice but and not used by sds but it can be tuned to maintain mixture, if turbocharged you can controll boost with the wastegate. And if your really savy haltech or motec can use additional outputs to control pitch on prop. Also not reccommended but both support throttle by wire throttle bodies. In one single ecu you have control of everything, you have data logging, faster processing speed, and you have tech support and can find a tuner just about anywhere.

Absolutely no reason in my eyes to run a dual ecu, old ecu, or have to run one for fuel only and one for ignition.

Who knows maybe ill end up in a corn field some where but ill be running haltech nexus and it will be controlling everything it can.
Its prety much the most afordable programable fadec control you can put together for an experimental and its proven. Look at every 24hr lemans or 24hr rolex sports car. Look at any 6 second pro mod with every sensor imaginable and ecu controlling everything from launching, traction control, shifting, even pulling the parachute. <not related but just what a modern ecu can do.


Well-Known Member
Nov 17, 2014
I'm a rotary enthusiast; there's a Renesis on the firewall of the RV7 I'm building. Their failure modes are mostly much more benign than piston engines, but the one significant weak point is that if you have any issue that takes out a rotor, it's a far bigger issue than losing a cylinder in a 4+cyl engine. You lose way more than 1/2 the power, and there's a real risk that torsional resonance will start breaking stuff (drives are designed for 2-per-rev).

There have been some rotaries that flew with carb & stock gen 1 ignition, and even with the stock automotive controller. Everyone has their own comfort limits. For me, it's about weighing the risk of failure, vs the extremity of the downside if it does happen. Kinda like wearing a parachute in an unlimited acro a/c.

To each his own...


Bobby Hughes

New Member
Jul 8, 2020
So which is it? :)

I'm a customer, I want options! SDS is dual ECU with mixture control.... just no ignition. :pilot:
SDS does not have a full rotary solution. If they did, many of us would buy one just to have continuing hardware support. I have a well proven EC3 but am still looking for an alternative increase the unit ever fails.