The Ghost of Andy Granatelli Tuned My Airplane!

[Bob Chilcoat]

Friday, one of my partners and I changed the oil. Afterwards, we took it up
for a spin to reward ourselves. As I rotated, I glanced down at the tach
and was rather horrified. Redline on the Archer is 2,700 RPM. We were
turning 3,300! 600 RPM over redline. Huh?! Since we still had the full
length of both prop blades, the only logical explanations are either that
someone put a different prop on in the dead of night, or that someone
sneaked up and hopped up the Lycoming. We have to be getting 240 hp to see
that much overreving on climbout. Wow. Thanks, phantom tuner. What a nice
guy...

Oh crap! The rate of climb isn't any different.

We've ordered a new tach.

--
Bob (Chief Pilot, White Knuckle Airways)

[[email protected]]

Is Andy Granatelli dead? Last I heard he was alive and living in
Montecito, CA.

David Johnson

[Jay Honeck]

> Friday, one of my partners and I changed the oil. Afterwards, we took it up
> for a spin to reward ourselves. As I rotated, I glanced down at the tach
> and was rather horrified. Redline on the Archer is 2,700 RPM. We were
> turning 3,300! 600 RPM over redline.

Great story -- thanks, Bob.

Question: I can understand how a tach fails and shows "zero" RPM -- but
how does it fail and show *higher* RPM?
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[BTIZ]

have the current tach calibrated before replacement.. those cheap hold in
your hand and look at the prop works pretty good.

BT

"Jay Honeck" > wrote in message
oups.com...
>> Friday, one of my partners and I changed the oil. Afterwards, we took it
>> up
>> for a spin to reward ourselves. As I rotated, I glanced down at the tach
>> and was rather horrified. Redline on the Archer is 2,700 RPM. We were
>> turning 3,300! 600 RPM over redline.
>
> Great story -- thanks, Bob.
>
> Question: I can understand how a tach fails and shows "zero" RPM -- but
> how does it fail and show *higher* RPM?
> --
> Jay Honeck
> Iowa City, IA
> Pathfinder N56993
> www.AlexisParkInn.com
> "Your Aviation Destination"
>

[Bob Chilcoat]

We did that a few weeks ago when it first started reading high. We found
that on the ground, it was consistently 10% high. However, in the air,
particularly this time, it was reading considerably higher and bouncing
around. I understand that one failure mode is for the shaft bearing to wear
and let the rotating magnet touch the aluminum drag cup. When this happens
it reads high and bounces around. Ergo, order a new tach.

--
Bob (Chief Pilot, White Knuckle Airways)


"BTIZ" > wrote in message
news:sTGrg.11095$6w.10302@fed1read11...
> have the current tach calibrated before replacement.. those cheap hold in
> your hand and look at the prop works pretty good.
>
> BT
>

[Bob Chilcoat]

I guess he's still around. Sorry, Andy. Rumors of your demise are greatly
exaggerated.

Perhaps I was thinking of Mickey Thompson or some such.

--
Bob (Chief Pilot, White Knuckle Airways)


> wrote in message
ups.com...
> Is Andy Granatelli dead? Last I heard he was alive and living in
> Montecito, CA.
>
> David Johnson
>

[Stache]

Bob Chilcoat wrote:
> Friday, one of my partners and I changed the oil. Afterwards, we took it up
> for a spin to reward ourselves. As I rotated, I glanced down at the tach
> and was rather horrified. Redline on the Archer is 2,700 RPM. We were
> turning 3,300! 600 RPM over redline. Huh?! Since we still had the full
> length of both prop blades, the only logical explanations are either that
> someone put a different prop on in the dead of night, or that someone
> sneaked up and hopped up the Lycoming. We have to be getting 240 hp to see
> that much overreving on climbout. Wow. Thanks, phantom tuner. What a nice
> guy...
>
> Oh crap! The rate of climb isn't any different.
>
> We've ordered a new tach.
>
> --
> Bob (Chief Pilot, White Knuckle Airways)

There are two different kinds of tach pick-ups for instruments. One is
direct drive from engine to tach by a cable the other is electronic
pick-up. If the engine sounds were the same I would think you have an
indication problem. Have your local A&P use a calibrated RPM gauge and
check you RPM this is the first test.

It may be a bad cable, faulty electronic pick up or just a bad tach.
You're A&P should know in short time what the problem is. Regardless
have it fixed before the next flight.

Stache