Posted by chucknugent on Wednesday, May 27, 2009 @ 01:20 AM:
As I get ready to tear down my 1700E for O/H ( 280hrs in 34 years, with very limited maint. ok nearly no maint.) I am thinking of installing 94s and second ignition. Has anyone converted to a second system and had any issues? What about improved engine operation ?
chuck
Posted by eugenio on Wednesday, May 27, 2009 @ 02:35 AM:
Well, I think secondary ignition on VW is just more weight and complication (keep it simple, as usually is said). Our engines are running since the early '60 and never had big problems. You only need to follow the magneto manufacturer's instructions/repair data to keep it in perfect conditions. In any case many people thinks it is safer to have dual ignition, so the most adopted system is the Great Plains secondary ignition system, that has been certified in Germany for the Sauer 2100. But be aware, you won't gain in performance, you only have a device that keep the engine running if the magneto system fails, and about a couple of Kg of more weight plus more cables running in engine compartment.
have a nice overhaul/upgrade
Eugenio
Posted by Jorgen on Wednesday, May 27, 2009 @ 04:08 PM:
Hi Chuck,
thanks or sharing your story, congratulations to a nice-looking RF 5 b and good luck with the overhaul. If you by 94's mean increase the cylinder volume I think it´s a good idea. SE-UDI has a 2 liter Limbach and I can take passengers out of ALMOST as short strips as with the RF 4.
I second Eugenio's comment (as usual) and I would add that I think the original notion that motorgliders have their safety in better glide (= better gliding range to a suitable landing spot) rather than a secondary, back-up ignition system in case of engine failures makes sense. This is more true in the RF 5 b than many other motorgliders, in my experience I¨d say that a 1:28 glide rate is not at all impossible with a folding prop. In addition, engine failures are not unheard of even in dual ignition aeroplanes and in a recent thread on a Piper Cub forum there was consensus to recommend an emergency (glider pilots call it "landing out" and it's not considered a big deal) landing instead of going for a dicey air restart. Quite a lot o Cub drivers seemed to have had engine failures.
And let's not forget that the Elvis equivalent in Fournier Flying, René Fournier himself called his biography "Mon réves et mes combats" (my dream and my fights- unfortunately I haven´t been able to get my hands on a copy yet) were the latter supposedly alludes to the difficulties in persuading the authorities to accept single ignition motorgliders on the above stated presumption. Let´s not prove him wrong, what?
Take 5(b) just 4 fun/ Jörgen
