Tach Attack

"John Kimmel" wrote

Here is a picture of the insides of a tiny tach. The gray stuff is soft
potting compound similar to BMS5-95. The battery was a common 3v Lithim
Ion button cell welded to the tabs before potting. If I ever find another
tiny tach that needs a new battery, I will cut a hole right over the
battery with a rotabroach or a mill instead of splitting the case. You
can't open the case without breaking it

http://tinyurl.com/tinytach

My tactic for splitting plastic cases is to use a dremmel tool with a thin
cut-off wheel, and cut right on the seam. Don't bother trying to pry it
apart, since they always crack like you have observed. When putting it back
together, I use JB Weld on the seam and quickly put electrical tape over the
seam. This holds the case together while the JB sets up and the tape will
later peel off, leaving a nice slick seam of JB. On a black case is
difficult to see that it has been taken apart, since the JB Weld becomes a
smooth surface that matches the plastic case amazingly well.

I have used this method to replace cells in power tool battery packs, and
the repair holds up to the extreme abuse they are subjected to.
--
Jim in NC

John Kimmel wrote:
Ron Wanttaja wrote:

Not a real drawback, as the tach also includes a secondary counter
that can still be used to keep track of minutes. However, 200 hours
is about five years of flying for me, and the built-in battery of the
Tiny Tach is only good for 5-8 years. At that point, I'd better hope
the company is still operating...or come up with some other solution.

Here is a picture of the insides of a tiny tach. The gray stuff is soft
potting compound similar to BMS5-95. The battery was a common 3v Lithim
Ion button cell welded to the tabs before potting.

OooooOooo, thank you! I've saved that shot for future reference.

Ron Wanttaja

canuck_bob wrote:
Gee Ron,

Your on a slippery slope. Digital displays and already planning your
next electrical upgrade! Could be evidence of that dreaded
psychological disorder known as Airventure Syndrome. We'll keep an
eye out for the major symptoms, obsessive urges to install IFR glass
panels, researching the installation of autopilot systems and weather
radar, and the most serious sympton requiring medication a small

I probably shouldn't confess this, but ever since the Dynon folks gave a
presentation at the EAA Chapter, I've really had the urge to install one
of their EFIS boxes on my Fly Baby. Just for the jaw-dropping
incongruity of it, if nothing else....

Ron Wanttaja

Scott a écrit:

Think back to the days when your electrical
system was 2 wires to a switch. ;-)

but now, electrical system may be more reliable. I read my old
continental engine health on an EIS 4000.
For my tach, I use two magnet on the flywheel, a reed contact and two
wires.

You know small continental d'nt have flywheel but a french guy make a
conversion for A65 with kubota permanent magnet alternator and
automotive starter. This kit may fit O200 too.
http://mdlaurent.free.fr/

I also use the magnets for CDI electronic ignition. no more magnetos,
no more cable for tach, no more copper tube for oil pressure...

By
--
« Si tous les poètes voulaient se donner la main, ils toucheraient enfin
des doigts d'auteur! »
Philippe Vessaire Ò¿Ó¬

On Sun, 09 Aug 2009 21:11:48 -0700, John Kimmel
wrote:

Ron Wanttaja wrote:

Not a real drawback, as the tach also includes a secondary counter that
can still be used to keep track of minutes. However, 200 hours is about
five years of flying for me, and the built-in battery of the Tiny Tach
is only good for 5-8 years. At that point, I'd better hope the company
is still operating...or come up with some other solution.

Ron Wanttaja

Here is a picture of the insides of a tiny tach. The gray stuff is soft potting compound similar to BMS5-95. The battery was a common
3v Lithim Ion button cell welded to the tabs before potting. If I ever find another tiny tach that needs a new battery, I will cut a
hole right over the battery with a rotabroach or a mill instead of splitting the case. You can't open the case without breaking it

http://tinyurl.com/tinytach


John
this is incredibly funny. they go to all the trouble of sealing up the
case and filling it to make it bullet proof and what is it that the
second reader of ron's post does?

pull one apart to see what's inside :-) :-) :-)

I love it!

Stealth Pilot

Stealth Pilot wrote:
On Sun, 09 Aug 2009 21:11:48 -0700, John Kimmel
wrote:

Ron Wanttaja wrote:
Not a real drawback, as the tach also includes a secondary counter that
can still be used to keep track of minutes. However, 200 hours is about
five years of flying for me, and the built-in battery of the Tiny Tach
is only good for 5-8 years. At that point, I'd better hope the company
is still operating...or come up with some other solution.

Ron Wanttaja
Here is a picture of the insides of a tiny tach. The gray stuff is soft potting compound similar to BMS5-95. The battery was a common
3v Lithim Ion button cell welded to the tabs before potting. If I ever find another tiny tach that needs a new battery, I will cut a
hole right over the battery with a rotabroach or a mill instead of splitting the case. You can't open the case without breaking it

http://tinyurl.com/tinytach


John
this is incredibly funny. they go to all the trouble of sealing up the
case and filling it to make it bullet proof and what is it that the
second reader of ron's post does?

pull one apart to see what's inside :-) :-) :-)

I love it!

Stealth Pilot

I think most of us have done that at one time or another. The hard
part is putting it back together with no parts left over.

Dan, U.S. Air Force, retired

Install the EFIS and double the value of your Flybaby.... grin...

John

Ron Wanttaja wrote:
canuck_bob wrote:
Gee Ron,

Your on a slippery slope. Digital displays and already planning your
next electrical upgrade! Could be evidence of that dreaded
psychological disorder known as Airventure Syndrome. We'll keep an
eye out for the major symptoms, obsessive urges to install IFR glass
panels, researching the installation of autopilot systems and weather
radar, and the most serious sympton requiring medication a small

I probably shouldn't confess this, but ever since the Dynon folks gave a
presentation at the EAA Chapter, I've really had the urge to install one
of their EFIS boxes on my Fly Baby. Just for the jaw-dropping
incongruity of it, if nothing else....

Ron Wanttaja

Morgans wrote:

My tactic for splitting plastic cases is to use a dremmel tool with a
thin cut-off wheel, and cut right on the seam. Don't bother trying to
pry it apart, since they always crack like you have observed. When
putting it back together, I use JB Weld on the seam and quickly put
electrical tape over the seam. This holds the case together while the
JB sets up and the tape will later peel off, leaving a nice slick seam
of JB. On a black case is difficult to see that it has been taken
apart, since the JB Weld becomes a smooth surface that matches the
plastic case amazingly well.

I have used this method to replace cells in power tool battery packs,
and the repair holds up to the extreme abuse they are subjected to.


I was already predisposed to believe the efficiency of this method.
Scaled up to an angle grinder with a thin cut-off blade (which are
amazingly rugged these days) I have opened an impromptu inspection
panel in a car door to replace the electric window winder clutch,
saving a whole bunch of hand wriggling in a narrow door space;
Carved a notch in a big bale carrier strut to put the load further
forward (If you ever had 1200 lbs of hay trailer wriggling a truck
like a girl with a hula hoop, you'd want to do this...) and cut off
a sink drain stopper funnel securing ring, long since corroded
to immobility. I am a believer!

Brian W

Philippe wrote:
....
I also use the magnets for CDI electronic ignition. no more magnetos,
no more cable for tach, no more copper tube for oil pressure...

By

Not sure if this is what you mean, but a few high energy magnets
spinning on a plate do a great job producing pulses in a few coils
spaced close to the spinning magnets.

Seems like you could easily arrange two sets of coils to provide a
double source for a CD ignition, as well as timing it....
Or perhaps more compact, a source (if rectified and smoothed)
for one of those electronic ignition modules that fit inside the car
distributor, these days....

Either way that really amounts to a magneto I suppose - but so few
components, and double redundant so no battery would be involved.....

Brian W

"brian whatcott" wrote in message
...
Philippe wrote:
...
I also use the magnets for CDI electronic ignition. no more magnetos,
no more cable for tach, no more copper tube for oil pressure... By

Not sure if this is what you mean, but a few high energy magnets spinning
on a plate do a great job producing pulses in a few coils spaced close to
the spinning magnets.

Seems like you could easily arrange two sets of coils to provide a double
source for a CD ignition, as well as timing it....
Or perhaps more compact, a source (if rectified and smoothed)
for one of those electronic ignition modules that fit inside the car
distributor, these days....

Either way that really amounts to a magneto I suppose - but so few
components, and double redundant so no battery would be involved.....

Brian W

I admit that I don't recall who manufactures and sells them; but I seem to
recall that Steve Wittman used a "self sufficient distributor" fitting that
description, as part of his V8 conversion for the Tailwind, at least 25
years ago.

Peter