Today's Message Index:
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1. 07:17 AM - Re: electric aileron trim (flyv35b)
2. 08:41 AM - Re: electric aileron trim (Scott Saylor)
3. 10:40 AM - Re: electric aileron trim (flyv35b)
Message 1
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| Subject: | Re: electric aileron trim |
--> TeamGrumman-List message posted by: "flyv35b" <flyv35b@ashcreekwireless.com>
> it was bound to happen. I had to remove an aileron from a Tiger with the
> electric aileron trim. Time for new bearings, you see. Well, who ever
> installed this electric trim did not leave any service loop in the wire.
There
> were no connections.
I've been through this very same scenario before with the electric aileron
trim and even with a connector it is much more difficult to replace an inner
aileron or flap bearing.
> So, my only option was to pull the aileron trim mechanism (ATM), add a
foot
> or so of more wire, and reinstall. The TM had been riveted to the
underside
> of the aileron. Not just riveted with #30 soft aluminum pop rivets so
the
> next guy could remove it without too much damage to the aileron, NO, not
this
> one. Every other rivet was a #20 structural rivet. By the time I got
the TM
> out, the aluminum skin on underside of the aileron was pretty badly
stretched,
> and wrinkled.
If memory serves me correctly, the rivets supplied with the aileron trim and
called out for on the drawing were 3/32 (#40) and were soft pop rivets. I
would guess that maybe the trim had been removed once before and the hole
egged out so someone installed larger rivets the next time (probably the
owner as I can't believe a licensed A&P mechanic would twist wires together
and use electrical tape!!)
> Next, I tried to remove the nut on the adjusting rod on the ATM. It was
> stripped. The adjuster is all aluminum and so was the locking stud and
nut. I
> had to cut it off.
The is a very weak design area as the original bolt and nut are soft
aluminum and not very strong and corrosion will seize them and then the bolt
breaks when trying to remove it. Aluminum was used to keep the weight down
to a minimum.
> I didn't notice anywhere on the alieron counter balance where the aileron
had
> be rebalanced after installing the ATM. I had to add a piece of .020
> aluminum as a doubler with tinnerman nut plates so taht I could screw the
ATM back
> in place and sandwich the aileron skin between the ATM and the doubler.
The STC installation drawing states that balancing is not required as I
recall. And the weight is so small that I can accept that, unless the
aileron was right at the limit of aft CG to begin with. It probably would
be a good thing to check balance of an unmodified aileron to find this out
before doing a modification.
> The quality of the parts in the ATM leaves a lot to be desired. I'd say
$30
> to $40 in hadware at the most.
I think you are right about this. The gear reduction parts appeared as if
they were out of one of the "slot cars" I looked at many years ago. The
experimental people use a very similar electric servo for the elevator trim
that they buy for less than $200. I guess that is what happens when you
have to buy the STC and pay whatever the asking price is, especially if
there is no competition.
> Bottom line is, to save a few seconds adjusting the fixed trim tabs adds
> (potentially) hundreds of dollars to the aileron AD inspection. Not to
mention
> the cost of the ATM and its installation.
All I can say is that the guy who sells the Aero-Trim has made a hugh amount
of money over the years with the immense profit potential that this system
likely has. And I would probably not spend the money to install one on a
Grumman considering the cost and negative serviceability factors.
Cliff A&P/IA
----- Original Message -----
From: <TeamGrumman@aol.com>
Subject: TeamGrumman-List: electric aileron trim
> --> TeamGrumman-List message posted by: TeamGrumman@aol.com
>
> it was bound to happen. I had to remove an aileron from a Tiger with the
> electric aileron trim. Time for new bearings, you see. Well, who ever
> installed this electric trim did not leave any service loop in the wire.
There
> were no connections. Just inside of the aileron torque tube (on the
inside of
> the plane) were four wires, they had black electrical tape on them. I
figured
> they had been soldered and black taped. I cut the wires 2 inches outside
> the torque tube, with the plan to put shrink sleeve on the wires and a
connector
> on the cut end so that the aileron could be R&R'd a little easier next
time.
> After I did the required maintenance and reinstalled the aileron, I
> proceeded to get ready to install a connector. When i removed the black
tape, the
> wires fell off. They were not soldered, just twisted together. And,
too far
> in the tube to solder and repair correctly.
>
> So, my only option was to pull the aileron trim mechanism (ATM), add a
foot
> or so of more wire, and reinstall. The TM had been riveted to the
underside
> of the aileron. Not just riveted with #30 soft aluminum pop rivets so
the
> next guy could remove it without too much damage to the aileron, NO, not
this
> one. Every other rivet was a #20 structural rivet. By the time I got
the TM
> out, the aluminum skin on underside of the aileron was pretty badly
stretched,
> and wrinkled.
>
> Next, I tried to remove the nut on the adjusting rod on the ATM. It was
> stripped. The adjuster is all aluminum and so was the locking stud and
nut. I
> had to cut it off.
>
> I didn't notice anywhere on the alieron counter balance where the aileron
had
> be rebalanced after installing the ATM. I had to add a piece of .020
> aluminum as a doubler with tinnerman nut plates so taht I could screw the
ATM back
> in place and sandwich the aileron skin between the ATM and the doubler.
>
> The quality of the parts in the ATM leaves a lot to be desired. I'd say
$30
> to $40 in hadware at the most.
>
> Bottom line is, to save a few seconds adjusting the fixed trim tabs adds
> (potentially) hundreds of dollars to the aileron AD inspection. Not to
mention
> the cost of the ATM and its installation.
>
> Gary
>
>
Message 2
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| Subject: | Re: electric aileron trim |
--> TeamGrumman-List message posted by: Scott Saylor <scott@thesaylors.net>
Cliff,
If you've ever stopped by this guy's booth at a trade show and talked to him, you'd
know this statement of yours is probably the truth. I envision him traveling
from show to show in an RV, making the kits as he goes. If I ever see him
in a coon skin cap, my suspicion will be confirmend!
Scott
"The gear reduction parts appeared as if they were out of one of the "slot cars"
I looked at many years ago. The experimental people use a very similar electric
servo for the elevator trim that they buy for less than $200. I guess that
is what happens when
you have to buy the STC and pay whatever the asking price is, especially if there
is no competition."
Message 3
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| Subject: | Re: electric aileron trim |
--> TeamGrumman-List message posted by: "flyv35b" <flyv35b@ashcreekwireless.com>
Yes, I have seen him several times and during conversation and looking at
his booth I was about as impressed as I am with his product. Not much to
say the least.
Cliff
----- Original Message -----
From: "Scott Saylor" <scott@thesaylors.net>
Subject: Re: TeamGrumman-List: electric aileron trim
> --> TeamGrumman-List message posted by: Scott Saylor
<scott@thesaylors.net>
>
> Cliff,
>
> If you've ever stopped by this guy's booth at a trade show and talked to
him, you'd know this statement of yours is probably the truth. I envision
him traveling from show to show in an RV, making the kits as he goes. If I
ever see him in a coon skin cap, my suspicion will be confirmend!
>
> Scott
>
>
> "The gear reduction parts appeared as if they were out of one of the "slot
cars" I looked at many years ago. The experimental people use a very
similar electric servo for the elevator trim that they buy for less than
$200. I guess that is what happens when
> you have to buy the STC and pay whatever the asking price is, especially
if there is no competition."
>
>
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