REFLECTOR: How to protect the battery bus
John Tvedte
johnt at comp-sol.com
Sun Feb 18 11:33:32 CST 2007
Ron,
Glad to hear of that. In my case, I chose the inline Skytec HTI. - which is a field wound starter. I have an IO-540K 340HP+ engine.
I still stand by my statement - but again, glad it works for you.
John
________________________________
From: reflector-bounces at tvbf.org on behalf of Ron Brown
Sent: Sun 2/18/2007 11:21 AM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: How to protect the battery bus
Just to clarify - the LS Skytec works GREAT!!!! I have #2 copper for my
starter wire and 1/2" ID copper tubing for my ground wire and it also is the
vacuum line. After 320 hours and lots of starts - never a bit of
hesitation. HIGHLY recommended - it turns fast and always cranks. By the
way, I disable Jeff Rose for the first 2-3 blades - then turn it on. Always
cranks with the next 2 blades when cold. Hot restarts are another issue -
but that is a Lycoming fuel injection issue. But the Skytec starter always
hangs in there for the generally 10-15 second run for the hot restarts.
A very satisfied Skytec LS user - on a IO360-200 HP.
----- Original Message -----
From: "John Tvedte" <johnt at comp-sol.com>
To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
Sent: Sunday, February 18, 2007 11:28 AM
Subject: Re: REFLECTOR: How to protect the battery bus
For us Lycoming folks - I would suggest the LS/PM Skytec starters are a
poor choice for our application, knowing we will have 30+ feet of starter
wiring. A wound field motor results in substantially less in-rush current
draw. I also suggest soldering the terminals on starter wiring. Internal
resistance of the battery is very important in starting applications.
Here is an example 'dialog' on the Aeroelectric list - where Rich Chiappe @
Skytec talks about in-rush current requirements in the 500-700 AMP range for
the LS/PM starters.
There is some chafe in here also - as this is the orig. post.....
John
On 1/3/200 Bob wrote:
--> If getting the best starter wasn't an option for me, then
adding the run-on eliminator would be a good idea. Bob . . .
It was a lovely implication that the Sky-Tec PM starter wasn't the best
for the customer's application. A bold jab, Bob. It's too bad we can't
keep things on this board geared toward matters of fact and not
opinion.
Rich my friend, I've never said that any Sky-Tec product wasn't
the best or worst for anyone's APPLICATION. In fact, I've often said
that Sky-Tec products are by-and-large good value . . . but
I'll support my statement about the "best starter there is"
by noting that while Sky-Tec starters are the product of
choice for many OEMs, they ALL looked at the B&C starter years
before Sky-Tec existed. They all offered to buy them in volume at
prices below cost of manufacturing . . . TCM even demanded
an exclusive on the IO-240 starter! They had some fixed notion
of acceptable price irrespective of performance. Nobody could
tear up a B&C starter on the test stand and they all tried.
I'm pleased that Sky-Tec was able to address the OEM notion
of proper pricing. Irrespective of what you or I might
say about their choice, it WAS a demonstrable quantum jump
in quality for users of those engines.
B&C starters run routinely and predictably to TBO on Robinson
helicopters and come back for overhaul looking like they'd
run another 2000 hours.
We're still hearing stories from Sky-Tec customers about
recurring incidents of problems that point to what may
be a combination of engineering or manufacturing problems.
We're assured by Sky-Tec that these are isolated incidents
and/or have been addressed with design changes . . . and
that's a good thing to hear . . . won't argue with it.
But if I hear of another multiple-failure event from
a Sky-Tec customer, you can bet yer sweet bippy, I'll
"jab" you again. My job is not to be spokesperson for
Sky-Tec, B&C or any other manufacturer . . . but to
hold them to the standards that customers are entitled
to expect.
When I used the term "best", it was akin to comparing
an Olds with a Chevy 6-cyl stick . . . there are marked
differences in design and manufacturing philosophies but
is the 6-cyl a "poor value"??? I drove nothing but
4 and 6-cyl, no frills cars until I bought my present vehicle,
a EFI-V6 GMC van with lots of extras. It depends on whether
one's mission and budget comfortably allows some risk of
inconvenience or discomfort in trade for difference in cost
of ownership of competing products.
Similarly, Firestones are product-of-choice for a lot of car
manufacturers but they're the only brand of tire for
which I've personally experienced tread separation . . .
TWICE. I no longer buy them myself but neither do I refuse
to take out a rental car fitted with Firestones.
If you can buy a set of top-flight Firestones for a good
price, they can be honestly said to be a "good value" . . .
but may I suggest that assessing "value" and "quality" are
different tasks.
What started this thread was a discussion about delayed
starter disengagement which is a characteristic of ANY
brand of PM starter when the builder elects to use an
off-board contactor for improved start switch life.
Here are some facts about Sky-Tec starters to help clear up some of the
misconceptions I've been reading on this board for close to a year
(plus) now:
First of all, not all Sky-Tec starters are the same. In short, we
manufacture two basic types of Lycoming starter: Permanent Magnet
"Flyweight(tm)" (LS & PM) starters and wound-field "Hi-Torque" (HT and
HTI) starters. Each has distinct advantages and trade-offs. As has
been noted on this board, the LS and PM starters achieve their
incredible weight savings (only 7.8 lbs) by utilizing a permanent magnet
motor. So while it offers incredible torque . . .
. . . "incredible" is difficult to quantify. Can you offer
comparative measured data?
. . . and unmatched weight, the
permanent magnet motor will draw more current than most on initial
in-rush (the split second required to get the starter motor turning
initially). This increased current draw is not a problem for the vast
majority of aircraft because most have electrical systems more than
capable of the incremental load (which explains why we've sold more
LS/PM starters than any other).
The "split second" is tens of milliseconds before the armature
is accelerated into motion that the motor draws "locked rotor
current". This is on the order of 500-700 amps depending
on ship's wiring, battery condition and style of starter. Until
twitchy processor based engine accessories came along, virtually
every user could happily ignore this short lived event.
This can happen with ANY starter brand or configuration depending
on ship's wiring, battery size and condition. Given that the vast
majority of aircraft are not fitted with electronics having
this vulnerability, it only makes sense and it's to your credit
that the lower cost, lighter technology has enjoyed a relatively
happy service history in the marketplace.
The LS/PM utilize brass bushings and a
plastic stationary gear and pivot arm which some have implied make the
starter less durable (metal must be better than plastic, right?).
Nothing could be further
from the truth. In twelve years of manufacturing lightweight starters,
Sky-Tec has NEVER seen a brass bushing or plastic stationary gear (or
pivot arm) fail - NEVER - ZERO - ZILCH. We could have engineered the
use of heavier/more expensive all ball bearings/metal gears/metal pivot
arms, etc. to be sure. But why? The result would be a heavier and
more expensive starter. To us, that didn't make sense at the time and
never will. Bottom line: If your application is a weekend flyer who is
sensitive to cost and weight (and your aircraft electrical system is
near par), the LS & PM is nearly always the best starter for you. We
have more than 20,000 LS/PM's out there - they work very well and those
that have them LOVE them in nearly all cases (as evidenced in fact by
the steady increase in their sales year after year, their use as OEM
starters on most aircraft and Lycoming factory).
No argument there . . .
The Sky-Tec Hi-Torque series of starters, on the other hand, utilize
wound-field motors that draw less current but tend to weigh just a
little more than the permanent magnet types (8.5 lbs for the HT and 9.4
lbs for the HTI - which is 1.7/0.8 lbs. lighter, respectively than the
B&C). The HT/HTI's are all steel construction and all ball bearing
construction so please don't let someone tell you that all "Sky-Tec
starters" (generic/plural) use bushings and plastic parts. Truth is
some do and some don't, as it turns out. It depends on the intended
application of the particular model of starter. If rugged, steel
construction is required by your application (bush operators,
helicopters, seaplanes, charter operators, severe applications, etc.)
then the HT and HTI are the way to go.
If your application utilizes dual electronic ignitions (no impulse
coupler or retard points available) and sufficient provision has not
been made for voltage supply during initial starting, you will find the
High-Torque Inline Lycoming (HTI also known as the "NL" model) starter
to be the best starter for your application. Any starter, regardless of
brand, can break on a kickback. Permanent magnet starters may pull the
voltage down below the ignition system's minimum tolerance and could
causing a ill-timed spark event. However, the High-Torque inline both
draws less current and has an internal kickback protection system (field
replaceable shear pin) that will enable you to avoid the damage and
expense of a broken starter or should a kickback occur, enable you to
repair your starter in the field while you fix your ignition
timing/voltage problem.
Wasn't aware of the field-replaceable shear pin. Sounds
like a good move.
. . . . As an aside, the High-Torque Inline Lycoming
starter also sports a sleek, inline form that allows it to fit
applications that would otherwise preclude someone from using any
lightweight starter (RG Cessnas, A/C'd Pipers, etc.) making it
pretty much the only 'universal' lightweight starter capable of starting
just about any Lycoming-powered aircraft (-235 through -720). So if
your application is a tight fit (Cardinal RG, Falco, etc.), the HTI
is the best starter for you.
The B&C Lyc starters were STC'd on the 235 through 720
right out of the gate. This is one reason why they started
with and retained the wound field design. The other was
lower locked-rotor current.
In addition, Sky-Tec also manufactures Continental and Franklin
starters and tendencies and features of one model do not necessarily
translate across the line to other models. Again, each is designed to
be the best for a particular application and may utilize different motor
architectures, gear reduction and other variables.
If we want to discuss which is "the best" general Lycoming starter in
the industry, Sky-Tec will gladly put our new High-Torque Inline
Lycoming starter against all comers for torque, ruggedness, low current
draw, light weight, fit, features, performance and price/value.
I'd LIKE to discuss it . . . but with data. Have you compared
your products with others on the data acquisition test stand?
I've invited Bill to sponsor laboratory testing on the full range of
starters in the marketplace and plot them all onto one
piece of paper. He's got a Lycoming shell that could
be fitted with loads for dynamic testing of starters. He
also has a stock of Prestolite "pig" starters that could
provide a testing baseline. I object to the non-quantified
terms like "incredible" and would really like to see
some comparison of the full range of products in the
marketplace.
Bill hasn't shown an interest in sponsoring this kind
of activity. Hmmmm . . . wonder if Aviation Consumer
or Light Plane Maintenance would sponsor an article?
A note on Magnaflite regarding the question on a previous post. I
would simply caution that anyone considering purchasing a Magnaflite
right now do some quick research into their recent Bendix recall before
buying into their "lightest/cheapest" pitch. As far as I can tell, the
Magnaflite will always be the cheapest lightweight starter available
because it is designed to be just that - the cheapest to make. They do
so by utilizing the same engagement method our grandfathers used on
their engines 50 years ago - the mechanical Bendix drive. Rarely do
motors/windings fail in starters. Typically the Bendix is the first to
go (most well before TBO). That's why Sky-Tec and B&C do not use
Bendix drives. Bendix failures account for probably 90% of "old style"
starter failures and they require constant maintenance and attention.
In 2003, Kelly experienced some problems with a supplier and suffered
some issues with premature Bendix failure. They seem to be addressing
those problems and have been very up-front with their customers from what
we've
heard. But the story is the same: with a Bendix, it's not a function
of "if" it's going to fail but "when" (then again, to be fair, I guess
ultimately the same is true of any mechanical device - but our
experience has proved without a doubt that electromechancal
solenoid-engaged drive will out perform the old Bendix by a long shot.
Agreed. I couldn't recommend an inertia-engaged
staring motor on anything but garden tractors
and outboards . . .
And finally, for all board posters that have questions/concerns about
Sky-Tec starters, please do not ever hesitate to call us and ask for me
personally. I try my best to tend to this board periodically but can
only do so as I find time. At our pace of sales, extra time is becoming
rarer and rarer. I will try to do so to keep up the quality of
information available on this board as I can, but if you prefer to get
instant answers, please feel free to call me.
I look forward to hearing from you.
Here is how to get in touch with me:
- Rich Chiappe
Sky-Tec
800-476-7896
richc(at)skytecair.com
As always Rich, I appreciate your time and support
of this List's charter to shine the light of data
and understanding through the fog of marketing
hyperbole and hangar legends. It can only serve to
make us all better at what we do.
By the way, I think there is a really good chance
that Raytheon Aircraft will be offering a full range
of testing services at what I trust will be attractive
prices to all comers by the end of 2004. There's been
a lot of grumbling amongst the bean-counters about how
our test labs have become a financial albatrosses. Years
ago, I used to enjoy access to Beech's labs in an
informal, over the counter basis. I could call out for
a window of opportunity and get in for a quick look-see
at my product's environmental vitals and walk out with
good data and a $75/hr tab to pay. I've got a charter and
encouragement from RAC management to see if we can renew that kind
of relationship with local industries who do not have
but can use such facilities.
It will probably be more like $150/hr today. Lab testing
will include the full range of DO-160 and MIL-STD-810
environmental tests . . . all or any part. I'm hoping
that we can attract/encourage a lot of developmental
investigation that often goes un-explored only to bite both
manufacturer and consumer at a later date.
I'm too close to retirement at RAC to consider more
than an assisting role but I may become a marketing
representative later on. Shucks, I've got a few products
of my own I'd like to shake, rattle, and zap if I
could get the right price! Keep us in mind should
you have need of such services. We've got some of the
best hammers in the business for beating on things to
see how well they are built!
Bob . . .
-----------------------------------------
( Experience and common sense cannot be )
( replaced with policy and procedures. )
( R. L. Nuckolls III )
-----------------------------------------
--------------------------------------------------------------------------------
> _______________________________________________
> To change your email address, visit
> http://www.tvbf.org/mailman/listinfo/reflector
>
> Visit the gallery! www.tvbf.org/gallery
> user:pw > Check new archives: www.tvbf.org/pipermail
> Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
_______________________________________________
To change your email address, visit http://www.tvbf.org/mailman/listinfo/reflector
Visit the gallery! www.tvbf.org/gallery
user:pw Check new archives: www.tvbf.org/pipermail
Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/ms-tnef
Size: 21190 bytes
Desc: not available
Url : http://www.tvbf.org/mailman/private/reflector/attachments/20070218/a32cb8c5/attachment-0001.bin
More information about the Reflector
mailing list