Instrument overhaul experience

Since the subject of new vs. overhaul comes up periodically, here is my
experience with the overhaul of a DG (1976 Mitchell aka Edo Air with
autopilot interface.) I sent it off to Bernard Ducasse in Pennsylvania
based on instrument shop recommendations found using Google Groups. Bernard
charged $400 for the rebuild and the two way, 2 day air shipping added $60
to the total. So far, after about 5 flying hours, the DG is working
flawlessly.

My only concern with Bernard is that he does not accept credit cards. It
took about 2 1/2 weeks to turn it around including the time for the check to
arrive and clear. This really wasn't a problem since I just plugged up the
open lines with dowels and clamps and continued to fly the plane.

Previously I had removed my analog tach and had it overhauled locally. The
cost was $60 and the tach is now giving accurate readings across the RPM
range.
--
Regards,
Mike

http://mywebpage.netscape.com/amountainaero/fspic1.html

Mike Noel wrote that he had his analog tach overhauled and that it is, "...
now giving accurate readings across the RPM range."

Mike,

How do you know it's accurate?

Just curious.

Jon

I had the tech run it on the bench with his digital cable driver from 1000
up to about 3500 RPM and the tach readout matched at each stage. I also
checked with my optical tach through the windscreen at 2500 and got a match.

Before the overhaul 2500 on the analog tach gave me 2580 on the optical
tach. I started to investigate the tach when I couldn't understand why the
static RPM on an obviously strong engine didn't meet the minimum book value.

I also learned from this exersize that the error was not proportional i.e.
an 80 RPM error did not translate to a 40 RPM error at half the speed.

--
Regards,
Mike

http://mywebpage.netscape.com/amountainaero/fspic1.html
"Jon Woellhaf" wrote in message
news:riRcd.414274$Fg5.254744@attbi_s53...
Mike Noel wrote that he had his analog tach overhauled and that it is,
"...
now giving accurate readings across the RPM range."

Mike,

How do you know it's accurate?

Just curious.

Jon

There is a way to tell if your tach is off. Move the plane so a street
light is shining on it from behind you. Run it up. A two blade prop
should appear to stop at 1800 rpm, a three blade at 1200 and 2400.
This is due to the strobe effect (the light blinks on and off).

"Jon Woellhaf" wrote in message news:riRcd.414274$Fg5.254744@attbi_s53...
Mike Noel wrote that he had his analog tach overhauled and that it is, "...
now giving accurate readings across the RPM range."

Mike,

How do you know it's accurate?

Just curious.

Jon

"Doug" wrote in message
om...
There is a way to tell if your tach is off. Move the plane so a street
light is shining on it from behind you. Run it up. A two blade prop
should appear to stop at 1800 rpm, a three blade at 1200 and 2400.
This is due to the strobe effect (the light blinks on and off).

Not outside the US...

Paul (running at 50Hz)

"Mike Noel" wrote in message ...
Since the subject of new vs. overhaul comes up periodically, here is my
experience with the overhaul of a DG (1976 Mitchell aka Edo Air with
autopilot interface.) I sent it off to Bernard Ducasse in Pennsylvania
based on instrument shop recommendations found using Google Groups. Bernard
charged $400 for the rebuild and the two way, 2 day air shipping added $60
to the total. So far, after about 5 flying hours, the DG is working
flawlessly.

A DG may be easier but I have never had an overhauled attitude
indicator work properly. I have never even heard of anyone who had one
work properly. I've found that I can buy them new for only about 10%
more than the price of the overhaul so I go for that (vac driven, not
autopilot or flight cues). The guys with the fancy autopilot attitude
indicators with flight cues probably just have to live with sending
the thing back several times.

BTW: If you are interested in how the last attitude indicator overhaul
went, check out my web page....

http://makeashorterlink.com/?G29D52E99


Notice the difference between the outside ground (which is below the
plane) and the attitude indicator (which shows the plane in a inverted
dive).

-Robert

"Mike Noel" wrote in message
...
[...]
Previously I had removed my analog tach and had it overhauled locally.
The
cost was $60 and the tach is now giving accurate readings across the RPM
range.
--
Regards,
Mike

http://mywebpage.netscape.com/amountainaero/fspic1.html



Where did you have your analog tach overhauled? I'll deal with your
overhauler next time. Keystone Instruments in Lockhaven, PA overhauled
mine for almost $200 and replaced the face even though I specifically stated
I did not want it done. Some of the overcharge was due to them returning
the damn thing to me COD (again against my express wishes) when I could have
given them my bankcard number. Poor telephone manners too.

The needle now swings so I average out the extreme numbers. And yes, I've
lubed the hell out of the cable and checked the ends.

BTW, the face job they did to my tach sucks. I wish it had the old face
back.

My overhauled gyros have outlasted the new by a factor of two so far. I bought the gyros new when I
upgraded from the old AN gyros. Both failed within 3 years, and I had them overhauled by a local
gyro shop. The overhauls have lasted over 6 years and are still going. Gyro bearings have a shelf
life once installed in a gyro. If the gyro sits more than about a month without being spun up, the
bearings develop flat spots. The shop that did my overhauls is local to me and put new bearings in
while I waited. I'd go with that type of overhaul before I'd go with new since you know the
bearings are fresh.

"Robert M. Gary" wrote:

"Mike Noel" wrote in message ...
Since the subject of new vs. overhaul comes up periodically, here is my
experience with the overhaul of a DG (1976 Mitchell aka Edo Air with
autopilot interface.) I sent it off to Bernard Ducasse in Pennsylvania
based on instrument shop recommendations found using Google Groups. Bernard
charged $400 for the rebuild and the two way, 2 day air shipping added $60
to the total. So far, after about 5 flying hours, the DG is working
flawlessly.

A DG may be easier but I have never had an overhauled attitude
indicator work properly. I have never even heard of anyone who had one
work properly. I've found that I can buy them new for only about 10%
more than the price of the overhaul so I go for that (vac driven, not
autopilot or flight cues). The guys with the fancy autopilot attitude
indicators with flight cues probably just have to live with sending
the thing back several times.

BTW: If you are interested in how the last attitude indicator overhaul
went, check out my web page....

http://makeashorterlink.com/?G29D52E99

Notice the difference between the outside ground (which is below the
plane) and the attitude indicator (which shows the plane in a inverted
dive).

-Robert

--
--Ray Andraka, P.E.
President, the Andraka Consulting Group, Inc.
401/884-7930 Fax 401/884-7950
email
http://www.andraka.com

"They that give up essential liberty to obtain a little
temporary safety deserve neither liberty nor safety."
-Benjamin Franklin, 1759

Hmm, I was rather happy with the job Keystone did with my engine gauge
cluster. I asked for refacing, and the gauges came back looking like new. I
thought the price was quite reasonable too at $704 for the whole 8 gauge
cluster.

jls wrote:

"Mike Noel" wrote in message
...
[...]
Previously I had removed my analog tach and had it overhauled locally.
The
cost was $60 and the tach is now giving accurate readings across the RPM
range.
--
Regards,
Mike

http://mywebpage.netscape.com/amountainaero/fspic1.html



Where did you have your analog tach overhauled? I'll deal with your
overhauler next time. Keystone Instruments in Lockhaven, PA overhauled
mine for almost $200 and replaced the face even though I specifically stated
I did not want it done. Some of the overcharge was due to them returning
the damn thing to me COD (again against my express wishes) when I could have
given them my bankcard number. Poor telephone manners too.

The needle now swings so I average out the extreme numbers. And yes, I've
lubed the hell out of the cable and checked the ends.

BTW, the face job they did to my tach sucks. I wish it had the old face
back.

--
--Ray Andraka, P.E.
President, the Andraka Consulting Group, Inc.
401/884-7930 Fax 401/884-7950
email
http://www.andraka.com

"They that give up essential liberty to obtain a little
temporary safety deserve neither liberty nor safety."
-Benjamin Franklin, 1759

Ray Andraka wrote:
: Both failed within 3 years, and I had them overhauled by a local
: gyro shop.

Which shop? My DG has about had it, and I'd like to get it overhauled
because it's got an autopilot pickoff. If the shop's local to you,
it's local to me, as well.
--
Aaron Coolidge (N9376J)