jasco stuff to chew on

[twing4@juno.com]

'this is gettin' kinda interesting. I agree that there has never been
a problem with Jakes,Lyc flat engines,or Pratt 985 or1340. Must have a
gajillion hrs on 'em installed in all sorts of ag planes. Many,many,
many 195s,B18s,450stearmans,Classic Wacos,L5s,etc have used 'em for
years. Don't know 'bout Rangers though there are probably dozens with
them. I just did some data searching and a funny thing pops up. It so
happens that the cont.w670 gen drive requires a stepup drive and
coincidently turns the gen/alt @1.95xcrank. A Jacobs-1.45,P&W-
1.5,Ranger-1.5,Wright760-1.252to1.37,Warner-unk. Hmmm. This means the
Continental is the only one capable of 50amp rating(albiet at redline)
Look at the skytronics speed chart and heed it. Check the load test
the mechanic filled out(it's required,he did do one right?). On a
Ranger you will only get 50amp at 2660rpm!Wowwee! The ole Ranger just
blowed 'er top! If you think the unit is 50 amp you're right,if your
installation speed is 4000 at the alt. Obviously,if you hit this at
redline then capacity is reduced at lower power settings. This is a
common installation error and old generators are no exception. The
data plate should give a capacity(amp)at a specific RPM. Less speed
and you won't get the full capacity. I think a Ranger running at a
typ. 2150rpm cruise with a Jasco will have a little under 40amp
capacity. This minus 20%(8amp) leaves you with 32 amp at cruise.
Still a whole bunch 'o power and if you can use up that you've got
WAY too many goodies in the plane(a coffee maker maybe?)
Nonetheless, the supposed failures are Cont670(3)and a
Warner. As discussed earlier unless a P&W is equipped with a 2:1 step
up drive then the Cont spins the gen the fastest. Any meat to that?
Don't know. As for the Warner check the type cert and it is pointed
out in the notes quite clearly,that the gen drive gears are suspect.
It says in a type cert that the gears must be magnafluxed. It seems
to me that that kind of info is normally contained to the O/H manual
& the fact it is noted in a type cert leaves one to think that these
gears are problematic. It also calls out the Champion gen as a no no
due to lack of a "flex" drive. Now the jasco has a sorta self
aligning coupling but doesn't seem to flop around like an Eclipse
E5A, at least when the jasco is new it seems a little stiff. Combine
these two items and wellllll.....maybe......
stay tuned'