I need to add a B&C backup alternator on for my Lancair IVP.  I had asked a build shop that was working on the airplane to add this but they failed to do that.

For the TSIO 550 which B&C alternator fits and is best choice?  SD20 or SD20-s? 

Obviously the short one gives you a little more room, but are there other considerations?  Does the SD20 tend to last longer?  What’s the point of B&C selling both if they are equivalent in everything but size?

Any help is appreciated.

Regards,

John Barrett, CEO

Leading Edge Composites

PO Box 428

Port Hadlock, WA 98339

www.carbinge.com