November 7, 2011 at 11:25 pm #83604
Is anyone using the Sky-Tec ST5 starter on a twin Cessna? I am interested in your impressions i.e. cranking speed, current draw and durability, plus anything else that comes to mind.
Thanks,November 8, 2011 at 4:06 pm #95154
I have an ST5, I think it is a better choice then the ST3 for the larger engines. It seems to spin ok. I think the best option is the TCM energizer field wound starters but these are the heaviest at about 8-10 lbs more.
You want to make sure the starter shaft doesn’t hold tension on the starter adapter. The Iskara starter does this, and it can wear the starter adapter over time leading to an expensive adapter overhaul – or worse.November 8, 2011 at 6:08 pm #95156
I currently have Prestolite starters on my 340A and was looking at the light weight starters. The M-Drive and ST5 starters are suppose to protect the starter adapter. Whether they do a better job of that is but one question. I tried the M-Drive but when I attempted a right engine start, prior to the left engine, the starter quickly slowed as if the battery were running out of energy, it wasn’t. So I am hesitant to try the ST5 as the same thing may happen.
What type of aircraft is your ST5 connected too? If a twin what is its performance when a right engine start is attempted with the left engine remaining shut-down?
I’m trying to be proactive in reference to the starter adapter, going the light weight route may be counter productive, what are your thoughts?
Thanks,November 9, 2011 at 6:53 am #95159quote GHANISCH:
Gary, I believe the heavy prestolite starters are the same as the heavy TCM energizer starters. This is the type of starter the starter adapter was designed for – I would not change a thing. The issue with the light weight PM starters is the shaft is “locked” by the magnets even when no power is to the starter. This is very hard on the adapter as it does not let the spring unwind. The ST5 and ST3 get around this with clutch type systems to disengage the two. The m-drive is similar but the Iskra has no protection – which is a shame since it is a well built strong starter that I believe is in wide use in europe as a diesel engine starter. However, without a clutch it is a bad application for our engines.
My plane is a Cessna 421C and I usually start left engine first (where the ST5 starter is). It seems to spin the same first or 2nd or 3rd try (need to work on my cold starts…)
For a twin, weight is less of a concern since usually it is close to the center of gravity – unlike a single engine where 10 lbs +/- near the nose is a big deal.
If you have the prestolite, I would stick with it. If it fails, I would overhaul it. If you go with a lightweight one, the prestolite core has value – please sell it to a shop that can overhaul it so that others can use it in the future.
If you want to save pounds, Hartzell (Kelly) has a new 100A alternator that is much lighter and smaller than the old Prestolite. I have been very happy with mine, and it looks much better then the new geared Plane Power 100A alternator (which is surprising since they make some nice stuff)November 9, 2011 at 4:23 pm #95160
Just a note on the Sky-Tec starters. If you have any trouble with them they MUST go back to Sky-Tec. They allow no outside field maintnance on their starters.November 9, 2011 at 6:09 pm #95161
Thanks for your thoughtful responses. I guess I’ll stick with what I have and take a look at the new alternators for future reference.November 9, 2011 at 11:59 pm #95162
Forgot, what is the weight difference between the Hartzell alternator and the old Prestolite?
ThanksNovember 11, 2011 at 4:43 am #95165
Here is some info on that alternator
I bought mine from these guys :http://www.2aps.com/esi_alt.htm They don’t list it on the website yet, the alternator is about 6 months old and Hartzell has not done much to market it. I think it is about 10 lbs lighter, and it is a much smaller case. Looks like a modern car alternator vs a generator off a tractor…
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