John and other Airmaster Owners,
In my nearly 20 years as an Airmaster Dealer, I have changed many a control
ler programing, and troubleshot systems and installations on many planes.
Nearly all of these were fairly simple to solve. However, on one occasion
I did simply swap out a controller (I still have the original and it works
fine.) It was discovered the belt driven alternator had a bad field causin
g massive EMP which affected the Hall Effect transducer in the brush block
(tach pickup). This was a bugger to troubleshoot. I knew it was the aux a
lternator as the prop worked perfectly with the alternator field wire disco
nnected.
As far as changing RPM settings with the program, it is an issue usually wi
th the difference in RPM shown on the Tach and that driven by the prop cont
roller. In all my years, I find tachs are notoriously off. I typically ta
ke my prop tachometer (optical device which counts the blades and converts
to prop RPM.) I calculate the gearbox ratio and show that the RPM at the p
rop is correct (confirming the programming), and the tach was off typically
within limits but at 5500 RPM a 2% error is obviously 110 RPM. (An error
that is OK for slow turning engines but not the Rotax.) I spent time with t
he clients researching the tach operational tolerances. I found the Airmas
ter tach pickup was more accurate than most tachometers, EIS or Engine Info
rmation Systems, and even certified tachs. But I was happy to help the cus
tomer fix his tach RPM error issue through the AC200 programming app rather
than trying to adjust a tach (especially an EFIS equipped with an engine m
onitor tach) issue. I was more interested in getting them flying safely wit
h no fear of overrevving the engine.
On another aircraft, we had the wrong gearbox ratio programmed, as the clie
nt had the 912S in mind when the prop was purchased but settled on a 912 UL
with the lower gear ratio.
I also found on a few occasions that customers that didn't take the tried-a
nd-true prop blade and diameter recommendations ( I was one of them) and th
e owner found many problems occur getting the prop to perform properly. Th
e owner blamed the settings, but on analysis I found the blade was too larg
e of an area for the engine power. Case in point, the 912UL cannot take a
prop any longer than 62 inches, a modest width and the tip must be narrow (
a tapered blade Warp Drive works well) unless really geared down. The wide
chord blade may be great for high altitude but at sea level you can't even
get 5400 for takeoff power with the 80-horse engine. Then at altitude the
power loss doesn't provide enough power and torque to even get the desired
cruise RPM. I purchased a propeller design program and spent inordinate a
mounts of time refining my blade choices for the Rotax to match the blade t
o the power and torque range of the Rotax 912, 912S and 914 engine versions
. This is not a fun drill as the customer is always right, and since he is
adamant on the blade choice, he gets to pay the dumb tax later when changi
ng blades.
John to your particular electrical issue:
If you were able to install the USB to Serial cable and hook to your laptop
successfully and make the RPM change it is possible during your hookup and
removal of cables (especially in tight areas) a circuit board may be damag
ed. Circuit boards can be brittle although the AC200 has very robust connec
tions, I can see how it will happen. For those who have never had an issue
, here is what the inside of an AC200 looks like:
[cid:3f2455a6-672e-48fb-867f-4d40b648d6b6][X]
One can see the pin connectors are quite robust but again, they are soldere
d, and a solder joint can break, or some part of the joint or board flake.
My concern with locking plugs is the Molex style connectors can be a pain t
o lock in and unlock. I no longer just plug in a Molex until I can see if
I can release it easily but still remain secure when clicked in. Heat shri
nk is normally placed on the end of a Molex connector and unfortunately the
heat shrink wraps under the push to release lever and can prevent full dep
ression of the lever and may prevent an unlanch for removal. I trim the he
at shrink to assure the hook side opens with clearance to spare. If a plug
gets stuck, I suggest to the client to bend the hook side to assure it cle
ars the latch and it should allow the plug to slide out easily rather than
trying to trim the heat shrink in place. In trying to remove the larger co
nnections sometimes torque is applied to the molex and the results can be t
erminal. I have also seen the power plug leaned on heavily and the ground
and or power connection solder joint causing a broken board or failed joint
. In my autopsy of this AC200, a small chunk of solder was found and it sh
orted on the board. (Even though the board is vertical, and one would thin
k the solder would simply fall to the bottom. He was unlucky as it caused
a short of course. However, most of the time a fried controller was a powe
r connected to the ground and vice versa. OOPS. As my friend Gary would s
ay... I'm going to pay the dumb tax for that." We've all been there.
Although I have never had this issue like yours, for servicing I make all
my panels easily removable and put the panel on the bench (sometimes I remo
ve the AC200 from the panel and do the update process on the bench). I hoo
k up my USB serial converter to my laptop, turn on the computer, call up th
e program and power up the AC200 and I've never had an issue. The softwar
e comes up (once I figure the com port on older non- automatic external USB
connection programs) I change the item on the screen and then close the pr
ogram and power down the AC200.
It would be nearly impossible for a digital to serial conversion cable and
processor to fry anything in a working propeller. So, I am sure it is not
the cable. As for other issues. If the prop was working before, I am stum
ped and blaming you, Airmaster or anyone else is inappropriate with what in
formation I have read on your issue.
There are other means of frying electronics though.
I have witnessed a fellow EAA member doing a show and tell at a meeting of
what happens when the battery is connected backwards. It can be exciting w
hen the mechanical master contact closes.
The only other AC 200 fried here in the States was due to an aftermarket vo
ltage regulator that shot A/C current direct to the panel. (A unique home-
made device.) As expected, those electrical components without reverse pola
rity diode protection died a quick death and some were slow and very diffic
ult to troubleshoot. I did hear of one guy (no firsthand knowledge) that h
ad a couple of jumper wires connected to the prop contacts trying to troubl
eshoot the hub not responding (he didn't realize the brushes were still in
contact) and he found with 12 volts applied to the prop and the still conne
cted brush block, cables and AC 200 controller, I can only say what he said
: I knew I fried it as it smoked and stunk to high heaven. He paid the d
umb tax of a new brushblock, cable, AC200 and he even changed out the switc
h.
Check if Dirk has a loaner AC200 at his shop (if you are working with him).
Relay to him the prop program you are working with, which motor is in the
hub. If you don't know, look in your logbook. so he can see if his spares
will work for you.
I have a complete test rig I made for those adamant that their install is c
orrect. It is shown below. It has a circuit breaker, AC200, switches ,and
can be hooked to a cigarette lighter socket via ring or spade connectors t
o connect a small gel cell battery. This is great for ground test and many
times to go fly on a test basis.
[X]
I had a Pipistrel owner that just couldn't get through his head, it wasn't
the prop but his wiring. (On panel tear down, the power plug had no ground
unless another component was turned on.) Heck of a thing to troubleshoot
with absolutely no panel wiring documentation.
Let me know what Dirk says. I've cc'd Jack Shaw at Airmaster so he is in t
he loop.
Email me off-line and let me know what you find.
Bud Yerly
US Airmaster Dealer.
(Retiring but still helping folks in any way I can.)
Cell 813 244-8354 (US Eastern Time or GMT -4)
email: budyerly@msn.com
________________________________
From: owner-europa-list-server@matronics.com <owner-europa-list-server@matr
onics.com> on behalf of John Kirkgaard <john.kirkegaard@gmail.com>
Sent: Monday, April 22, 2024 1:46 AM
Subject: Europa-List: Re: Airmaster SoftWare update
com>
DuaneFamly,
I'm absolutely sure that the update-software is not made faulty by intentio
n.
In Europe we have a extremely good support by Airmasters representative.
Unfortunately he has been on a long (well deserved) vacation, and I had to
rely on support from Airmaster in N.Z. And to be frank, getting help from
there is like contacting an Indian call center.
Looking back, I should have been more patient and waited for the normally
excellent support from Dirk.
Regards
John
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