REFLECTOR: Lycoming starters

Sun Nov 27 16:14:53 CST 2005

Scott, 

Im using a conduit ground like the one in the AeroElectric pages. I have 1/2" copper conduit running down the right duct, with #2 wire inside it for the feed.  I checked up on the aeroelectric site about installing a diode or special charging splitter like I had planned, but was convinced after reading that it was not necessary. It might make the most sense in yours since you are in retro-fit hell :)  I went ahead and installed a contactor for each battery. I ended up using 2-B&C batteries in the nose. I can start on either one or both, have 2-16AH batteries that I can isolate, and the total weight of the batteries is 33 lbs. According to my magic pencil, I won't need any extra weight up front (at least not a whole battery's worth). 

I was amazed at how little resistance the 1/2" copper conduit had.  I think your setup will work out fine.  I won't have the heat soak problems due to the way my exhaust runs and the cooling flow is. Cross your fingers. 

I still need to get up there some time and take a look at your project. Just busy as always.  

Keep us updated,   Kurt 

-----Original Message-----
From: Scott Derrick <scott at tnstaafl.net>
To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
Sent: Sun, 27 Nov 2005 14:54:28 -0700
Subject: Re: REFLECTOR: Lycoming starters

I already have one of SkyTec's lightweight starters installed on my rebuilt TSIO520. Hearing about the problems some have experienced with these starters when they were heat soaked has convinced me to plumb in a cooling shroud for the starter.  
I was already somewhat worried about delivering electrons to any starter capable of turning over the 520. While I never had problems with my IO360, yes I do use an Odyssey battery, best starved electrolyte battery made, I was wondering about the additional torque, and thus current, needed for the new engine. 

The builder made a not so wise installation decision by installing a #2 ground return and a 00 positive cable form the front to the rear. I don't know why somebody would install such a out of balanced electrical feed but they did. I planned on somehow rectifying that. 

I had initially decided to replace the heavy high pressure hydrolic hoses that ran form the engine to the nose oil cooler with 1/2 aluminum lines, one installed in each duct to turn the lines into oil coolers. Thinking about this I heard some had used copper lines. Then I heard some had used one of the lines for their ground return! I decided I would also use copper lines but use both lines for my ground return. bonding the lines together at both ends to end up with a large ground return, better cooling and reduce the weight by eliminating the existing #2 line and HP oil hoses. I then noticed the hard stainless lines form the engine inlet/exit where 5/8, so I installed 5/8 copper lines instead. 

I think the voltage drop should be minimal running through a 00 cable and 2 5/8 copper lines. As long as I can keep the starter cool! 

I also need to add some weight in the nose to get the CG back where it should, the TSIO520 weighs a bit more than the IO360, some of this will be in the addition of another Odyssey. I'll use both batteries for starting and run on one with the extra as a emergency backup, charging via a diode. 

Scott 

NMFlyer1 at aol.com wrote: 

> I was talking with B&C a couple weeks ago about the final wiring for > my battery and starter circuts. I was asked if I had a Permanent > Magnet Motor, or a field wound. At the time I didn't know and had to > look up the Chevy Part and found out. Most Starters are permanent > magnet motors and they are less efficient for high torque applications. 
> > As it turns out, I have a PMGR starter (permanent Magnet, Gear > reduction) in the Chevy V-6 in my Velocity. The Voltage rating is > what they expect/need at the starter motor, usually after a few seonds > of cranking. There is a pretty good explination of this in > AeroElectric papers. 
> > In a canard-pusher, the starter situation is about as bad as it can > get. Battery in the nose, starter in the back, long wires, etc. They > say to optimize this, use good FAT wires, Good grounds, and an RG (or > starved electrolyte, Glass mat, or many other terms) battery. This > will make sure that the starter gets as much power as possible > considering the situation. 
> > My old Cherokee 235 has the battery behind the baggage bulkhead, not > great cables, and the old inefficient starter. Needless to say, when > it is cold (or very hot) it shows up trying to start the O-540. I > didnt want to spend mega-bucks to buy a new starter, or change out the > cables if I didnt have to. So, I replaced the old style flooded cell > battery with a new RG battery. The starter now spins much better and > longer, and I have no starting problems at all. The lower internal > resistance in the battery, and high cranking amps work wonders! They > are also less prone to self discharging and cold weather problems. > Yesterday I fired up the Cherokee after not flying it for 2 weeks. It > was 27 degrees outside. No preblem. 
> > So, My advice would be to START with an RG battery. It is the easiest > and by far least expensive starting point. It just may cure the > problems (providing you dont have some defect in the system). If you > still have problems, at least you know it is not the battery and you > will be pleased with its performance anyway. 
> > Hope it helps. 
> > Kurt 
> 
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