Javelin rudder trim, approved in TCDS A-799

[hilltop170]

Does anyone know anything about;

*409. Javelin rudder trim according to Javelin dwg. No. 719 (sheets 1 and 2 5 lb. (+123) (+123) (+123)
revised April 14, 1955) and Instructions dated March 1955. Airplane Flight Manual Supplement for Javelin Rudder Trim dated May 20, 1955, required.

Approval for the installation of all items of equipment listed herein has been obtained by the aircraft manufacturer except those items preceded by an asterisk (*). The asterisk denotes that approval has been obtained by someone other than the aircraft manufacturer. An item marked with an asterisk may not have been manufactured under a FAA monitored or approved quality control system, and therefore conformity must be determined if the item is not identified by a Form ACA-186, PMA, or other evidence of FAA production approval.

Can this be fabricated from drawings and installed by log book entry as an owner made installation?

Do drawings and Airplane Flight Manual Supplement for Javelin Rudder Trim dated May 20, 1955 exist ANTWHERE ????

[GAHorn]

Under older, now obsolete, CAA regs certain mods which today would qualify as STC's were submitted by their owners and gained approval and listing on the TCDS.

It would not be possible today for an owner to make and install with only a logbook entry an item that has approval via STC. (Imagine an owner manufacturing a complete Horton STOL kit copy in his hangar and installing it and making only a logbook entry.)

I believe it's the same for obsolete alterations/modifications.

[Bruce Fenstermacher]

George I'm not quite following you.

I believe that if you have the installation instructions and can produce the parts required if any under owner produced parts, then you can install or modify your aircraft per the TCDS with just a log entry.

For example in our 170 you could under the owner produced parts rule, build a Javelin fuel tank and it's components and install them per the TCDS and the Javelin instructions with just a log entry. It might be a stretch that you could actually build the tank but it is not impossible.

Another case with a different aircraft I'm very familiar with is a Clipped Wing Cub. You may recall I own one.

The Reed Clipped Wing modification is the last item added to the type certificate. If you locate a set of Reed instructions and follow them to letter, you can cut 6 feet of wing off you Cub, modify the struts, bend the strut attach points with torch and hammer assemble it all and make it legal with just a log entry. BTW there are clipped wing STCs similar to the Reed Clipped Wing modification. You couldn't do one of these STC'd modifications with just a signature and no permission.

The fact that something is included in the TCDS would supersede an identical STC. In other words while I'm sure there are some there would be no reason for a Supplement to the Type Certificate (STC) because it is already part of the Type Certificate.

[Bruce Fenstermacher]

Oh I forgot, I don't believe there is anythings such as an obsolete alteration/modification as long as it is still part of the TCDS and has not been changed or forbidden by an AD.

[GAHorn]

Oh I forgot, I don't believe there is anythings such as an obsolete alteration/modification as long as it is still part of the TCDS and has not been changed or forbidden by an AD.

I didn't intend to say the alteration/modification was obsolete. I was refering to an obsolete policy in which an aftermarketer could have his/her modification added to the TCDS. Today such a process would be handled by STC.

In order to manufacture a Javelin auxiliary tank one would need much more than the installation instructions in order to comply with the Owner Produced Parts rule. One would need to have detailed design, materials, and engineering data. It's unlikely an out-of-business operation such as Javelin could supply such information, and it's also unlikely that even if still in business, they'd be inclined to do so.
Reverse engineering is sometimes employed in owner produced parts, however. (If you can find someone with a modification who'd allow you to tinker with sufficiently to accomplish the task....or find one in a junkyard along with the installation instructions. In other words, ... practically speaking... the answer is still "no".)

[Bruce Fenstermacher]

Yes I agree as I previously stated it might be difficult to acquire the parts through any method available including the owner produced parts rule but not impossible.

So back to Richard's original question.

Can this be fabricated from drawings and installed by log book entry as an owner made installation?

The answer is yes assuming the drawings are sufficient to manufacture the parts necessary or the parts are available through some other legal means.

BTW it is these types of obscure drawings and installation instructions I'm most interested in collecting for the associations library.

[hilltop170]

Thanks Bruce and George-

From what I gather from your comments, it would be possible to legally reverse engineer it as an owner produced part if either paperwork or an actual example could be found to duplicate. That answers one part.

So, back to the other part of the original question, Has ANYONE seen one of these or have one on their plane, or have any of the paperwork associated with it?

My mechanic in Alaska remembered seeing one years ago. He said it was a bungee type trim similar to the factory C-185 rudder trim attached to and applied force onto the rudder pedal system not back on the rudder as a moveable tab.

Sometimes it would be nice to have rudder trim.

[blueldr]

I have seen a very neat electric rudder trim on a homebuilt that was simply made from a large size control servo used on a radio controlled model airplane. It was a DC motor and simply reversed the polarity to reverse the motor rotation. A very slick device.

There is an electric trim system that is STCd for the C-170. Seems to me the owner is down in Florida.

[Bruce Fenstermacher]

Bl that electric trim system is STC'd for the aileron and is approved for just about every plane there is. The STC holder claims the system could also be adapted to other areas such as a rudder but it is not STC'd for this purpose.

I have one of these systems on my 170 in the aileron. It is not very effective at least on my airplane and I never move it from neutral. I would not recommend anyone spend money on it for a 170.

[hilltop170]

Bruce-
I've heard the same thing as far as not very effective on the ailerons but what do you think about its effectiveness if you put it on the rudder? You could always size-up the tab to make it effective on the rudder.

If you have any info on the electric trim, could you scan and email it to me? Or maybe mail or fax it? My Turbine Birddog buddy is also interested as he really needs rudder trim, and he can install it without approval since the TBD is Experimental.

[Bruce Fenstermacher]

Richard

As I said the electric system IS NOT STC'd for use on the rudder though the owner says it could be used there. Actually he does have it approved for rudders on Mooneys, Beechcraft and Lake aircraft. If you used it under the STC for the rudder you couldn't change the size of the tab without getting approval because the STC doesn't cover a larger tab.

I'll save your buddy about $600 and tell him to go to the hobby store and buy the biggest R/C servo he can find. Cut a hole in the side of his rudder and mount the servo in it. Run a control rod to hinged trim tab. Run wires to the cockpit.

Here is where it gets a little tricky. He'll have to find an RC electronics guy to design and build a servo driver. This basically consists of a potentiometer that varies voltage to each side of the servo potentiometer and makes the servo match the position of the driver pot. Simple stuff 20 years ago but don't know if anyone uses them today.

That is all the STC'd system is. Here are some photos of it.



Looking at the first photo you see the servo on the left. A big square hole is cut in the aileron or rudder skin and this servo mounted to the skin with pop rivets. (yes pop rivets). in the second photo you can see the guts of the servo which would be covered with a thin plastic cover in actual use.

The gauge to the center of the photo actually has a left right switch in it. As you move the switch and move the trim the indicator moves tracking the trim tab. This indicator is a FAA requirement I understand but your buddy wouldn't need it. Otherwise the controller is just a servo driver of RC days past.

[hilltop170]

Bruce-
Is that electric trim kit still on the bench or did you install it? Unfortunately, neither my buddy or I are savy enough to figure out the R/C servo thing. If the kits are still available, that would be the way to go, even on an experimental plane. And maybe I could even get the rudder trim field approved in Alaska. Who knows until you try?

Can you give the contact info for the manufacturer?

Thanks

[GAHorn]

Aero-Trim, 1130 102nd Street, Bay Harbor, Florida 33154

305 864 3336

[Bruce Fenstermacher]

George beat me to it. No the system pictured is not installed. I bought it a long time ago for a Cherokee I owned but never installed it. When I bought my 170 it had the same system installed so I'm keeping this one for spare parts.

I have an interesting story about the owner, his products STCs, how he has conducted business in the past with the FAA which is just to long to relate here but I'll have to tell you when we meet next at a convention.

Basically though his product is what it is and the STCs are legitimate and I had a very good experience dealing with him directly at Sun N Fun many years ago. I just wouldn't follow his advice as to how the product can be installed and by whom and what and how to do the paperwork we all love so much.

Richard to be honest this product was cutting edge 30 years ago but todays electronics and manufacturing processes make it look like the relic of the past that it is. If I was your friend I'd rather tie a bungle cord between a rudder pedal and the seat for a trim than install this in a rudder or an aileron for that matter.

If you can't figure out the R/C thing I'd investigate more modern trim systems available using derivatives of R/C and automotive components that are available for the experimental aircraft. Look here for a good start. http://www.rayallencompany.com/index.html

[GAHorn]

Richard, (taking my official-hat off and putting my gimme-cap on) ... you might ponder what a friend once did:

He installed a genuine Cessna system into a different model Cessna... logged it as a minor alteration with a simple log entry, quoting the genuine Cessna parts utilized.... and all subsequent inspectors never questioned it.

In other words, if it's good enough for a Cessna L-19 (etc.) ... mightn't it be suitable for a 170B?