What is the difference between a single , and dual idle?

[James]

What are the differences between a single rotor idle , and dual rotor idle?

[Anthony Duffield]

James,

Good question, I suspect its for an air cooled?

Anyway I think you mean; single idle is the engine is running on one rotor, the other rotor spark is switched off by the ignition unit etc, so it is not firing, dual idle on my Commander means it idles on both rotors.

Hope this helps

Tony

[rustynuts]

Not quite right Tony.

Due to low friction, the rotary engine will naturally idle at a high speed with the SU carb set up. On the single idle machines, the throttle microswitch opened an air valve to induce drag on one rotor in order to make the engine idle at a sensible speed. Dual rotor machines had the black "retard box" added to provide ignition retard to the fixed advance of the original Sparkrite ignition unit in order to provide a low idle speed.

Only early IP2s had single rotor idle and most were factory modified to dual rotor idle. The later Boyer unit on the Classics and Commanders and the aftermarket ignition units all feature the ignition retard function.

[Anthony Duffield]

My experience is all Commander, my original Boyer ignition and my now fitted Minimag all featured the retard function, both Boyer and Minimag go to retard 800 RPM.

Thank you for the correction.

[t140v]

Not quite right Tony.

Due to low friction, the rotary engine will naturally idle at a high speed with the SU carb set up. On the single idle machines, the throttle microswitch opened an air valve to induce drag on one rotor in order to make the engine idle at a sensible speed. Dual rotor machines had the black "retard box" added to provide ignition retard to the fixed advance of the original Sparkrite ignition unit in order to provide a low idle speed.

Only early IP2s had single rotor idle and most were factory modified to dual rotor idle. The later Boyer unit on the Classics and Commanders and the aftermarket ignition units all feature the ignition retard function.

My single rotor RE5 runs at just over 1000rpm with a SU , no different to when the horrible twin choke Mikuni is fitted.