Al,
Looking at a picture of your engine install (very nice), it appears that you’re running the factory Mazda (Mitsubishi) alternator? If it is the same as those I have on hand, they weigh about 11#. My rationale is that two ND alternators weigh 5.5#/ea, so there is little to no weight penalty. If you could get by with a single ND unit, then you should see about 6# net savings. In the conversion, I gained a second wp belt as well as electrical redundancy. With the batteries back in the tail, I need plenty of amps to crank the 3-rotor (Batteries cross-feed during starting). Add an all electric panel, and I felt the weight of the extra battery was worth it. From what I’m told, most Lancair ES’s are nose heavy, at least with the IO-540 engine. Also, all the Lancair ES’s I’ve seen are running two batteries, located in the tail.
I’ll be doing the W&B soon, so we’ll see how it does compared to those “certified” guys.
Mark
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Buly
Sent: Wednesday, January 25, 2006 9:35 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Two Alternators?
On Jan 25, 2006, at 10:23 AM, Al Gietzen wrote:
I have 2 alternators – although since I have 2 batteries and I’m heavy (the plane that is) – I’m considering taking one of the alternators out. I mounted the second alternator on the intake side just above where the water inlet is. This picture isn’t very good – but you get the idea of where it is. It’s a small 6lb. Powermaster alternator.
Regards,
It would seem that taking out one battery would get rid of more weight; unless you have some other reason for wanting to get rid of the second alternator. Although I’d say a battery is more reliable than an alternator.
I think two batteries and two alternators is redundant redundancy, and a weight penalty. But that’s just me.
Al
I'm with Al on this. I have one 70A alternator and two batteries at the nose for CG purpose.