Chapter 22 – Nose Gear AEM Box

Here’s the latest status on the Nose Gear Auto Extension Module (AEM) that will replace Jack Wilhelmson’s original AEX feature.  First off, I sent this pic to Marco to help show him why I had a requirement that the AEM box be 1.8″ or less: since the AEM box will be mounted in the old AEX box spot, where I have a notch in the top aft side of my NG30 cover that is just a hair wider/deeper than 1.8″.

After a number of discussions back & forth with Marco on the particular specs of the AEM box he was able to generate these fantastic renderings of the box.

Here’s the initial rendering.

Then one with the lid and raised letter labeling.

One of the aft, left and top side.

Finally, one showing the internal standoffs for the two airspeed switches and mounting screws.  As you can see, he has included the 15-pin D-Sub connector in the renderings as well.

In the next few days Marco will 3D print this AEM box when he gets a chance.  I just really have to say that everything for the new nose gear wiring & AEX system is going exceedingly well!

 

Chapter 25 – Self-rolled Bridge Sander

I took a bit of break from my normal build actions to do a quick tool building project. Starting yesterday & finishing today I’ve been working on constructing a bridge sander as Nick Ugolini spells out how to do on his blog.  Once again, I was notified of this brilliant contraption by the watchdog of the canard world, my friend Dave Berenholtz who is blazing through his Long-EZ build down in OZ (check out his blog here).  Coincidentally, Mike Beasley also built one of these as he was finishing up the major sanding of his Long-EZ as well.

For the base, Nick calls for using 1/16″ thick x 1-1/2″ wide aluminum that you can easily buy from Lowe’s, Home Depot, etc.  I did pick up some of that aluminum for the micro spreader, but for the sander it just wasn’t wide enough for me so I picked up a cheap automotive rigid sander at Harbor Freight after assessing that the aluminum base looked as if it would be amenable to getting pressed into service as a flexible sanding board.  As for parts, one other point of note: Nick calls out for 1″ square tubing to be turned into 6 U-channel pieces and then a separate piece of 7/8″ U-channel to be used inside the 1″ share tubing/U-channel above.  Well, I found the 1″ square tubing, but not the 7/8″ U-channel so I ended up using some 1″ wide U-channel I had on hand with 1/8″ walls, then buying 3/4″ U-channel to go inside that.  Just a slight variation that worked out really well.

I started off by ensuring that I could dismantle the Harbor Freight sander to ensure I wouldn’t destroy it in the process.  I peeled the rubber pad off the bottom of the base to gain access to its 4 handle mounting screws.

I simply used my fingers to pry off the bottom rubber pad, with an occasionally use of my utility knife to round up any errant pieces of rubber that decided to stay on the aluminum rather than come with the rubber pad.

With the sander broken down into an acceptable number of pieces, I then did a final assessment on whether the aluminum base would be flexible enough to be used in this type of sander.

Since the base off the HF sander is only 0.01″ thicker than the 0.063″ (1/16″) called out for by Nick, it looked as if my eevil plan was going to work!

An added bonus in using the HF sander was that the screw holes in the base for holding on the wood handle are at the perfect dimensions that Nick calls for on his blog: approx. 1-1/2″ and 6″, respectively, from each end.  Pretty cool.

I cut enough of the brackets and aluminum pieces for two of these things since I’ll also be building the micro spreader, but I wanted to get the sander under my belt first.  I marked up the U-channel for 12 each 0.9″ wide brackets, 6 for the sander and 6 for the micro spreader.  Of the 6 brackets for each, 4 will get normal holes drilled through them while 2 will require slots.  Since I’m using cheaper Zinc bolts, 1/4″ is the smallest diameter I could get (versus the 3/16″ AN3 hardware Nick used).

For easier drilling of the holes and the slots, I drilled them all before I cut the U-channel into the respective brackets.  Yes, since I don’t have a mill my slots are pretty sloppy, but for this purpose I’m sure they’ll work fine.

I then cut 12 brackets from the U-channel

And then cut the 3/4″ U-channel into the approximate lengths for the first layer of cross supports.

Finally, I cut the 1/16″ x 1-1/2″ aluminum for the micro spreader to 16-1/2″ long.  I also cut 2 longer lengths of the 3/4″ U-channel stock for the top cross supports/handle bases.

I drilled the 4 holes through the U-channel for my bridge sander and mounted the handle base.

And then started the arduous process of cleaning up each bracket.

I cleaned up 4 straight-holed brackets and 2 slot brackets for the bridge sander, and left the 6 brackets for the micro spreader for later.

I then mocked it all up to see how it would look.  Not bad!

I then drilled a hole in each of the bottom brackets that attach to the base for mounting.  I drilled them just a bit off-center to allow for mounting one countersunk rivet through the base into each bracket to keep the alignment straight.  This was the last action of the evening since I wanted to ponder on the handle a bit.

I called it a night, but I couldn’t help but get the feeling that I needed to go with the “traditional” 2-handled setup vs. using the HF sander’s wooden handle.   So this morning I used the handle base/cross support 3/4″ U-channel stock that I had cut for the micro spreader and drilled the final holes into it to allow it to be bolted to the two sander cross supports, and also add two 3/8″ bolts for handles.  I cut about an inch off the top of each handle bolt to allow me to use rubber slip-on grips from McMaster-Carr.

It looked good, but my quick testing of it proved to me that it’s the downward force against the surface being sanded that determines the conformal action of the sanding base, not the actual configuration of the handles.  So my initial hunch was right, and thus I’ll drill up the the base with the wooden handle to see how that works.

I have out-of-town company so the build will be a bit slow over the next few days, but I am happy that I got this reportedly invaluable finishing tool constructed.

 

Chapter 22 – Final Brackets, this time!

After the BID glass cured on the Throttle Handle electronics cable P4 connector bracket, I pulled the peel ply and razor trimmed the glass.  As I was redrilling the connector mounting holes I set this connector body in place to ensure the spacing was good.

So, here’s the final product for Throttle Handle electronics cable P4 connector bracket.

I then did pretty much the same thing for the Dynon Intercom bracket: pulled peel plied, razor trimmed, redrilled holes and sanded it all to clean it up.  I then set the intercom in place to see how it fit.  I’m definitely happy with how this intercom mounting is turning out so far.

What I’m not happy with is the forward right bracket nutplate.  It’s giving me fits and I’m going to have to drill it out and remount just a hair forward and inboard for it to align correctly with the intercom mounting hole.

Of course the other 3 nutplates went in without any issues, unlike the last one!

Besides redoing the 4th nutplate, I’ll also assess whether or not I need an angled strut at one or either end of the bracket to help support the cantilevered intercom.  I must say that this bracket is amazingly strong, but with vibrations abounding in flight I think I’ll throw on one small corner bracket to bolster it a bit.  It will weigh next to nothing but will add a lot of structural support.

 

Chapter 22 – More Brackets & RCU

I started off today by razor trimming the bracket for the Throttle handle electrical cable P4 AMP CPC connector.

I did the same thing for the right armrest-mounted Dynon intercom bracket that I just glassed in using 2 plies of BID.  On both of these brackets I was able to knife trim them right at their curing sweet spot, so the glass was definitely more on the cured side, but still just a tad pliable . . .  so it cut well.

I then laid up 2 plies of BID on the bottom side of the Throttle handle electrical cable connector bracket.  I used a small flox fillet in the corner and peel plied the glass junction with the sidewall.

I did pretty much exactly the same thing on the Dynon intercom bracket only for a bit more strength I used 3 plies of glass on the bottom side.

Speaking of brackets, I just received this today so I thought I’d throw it on the blog.  This is the fuel injection spider mounting tab that goes on the top centerline of the engine.  Yet just another item that will go on the shelf for the time being.

With my bracket glass curing, I started in on mounting the 4 beefy relays into the gear Relay Control Unit (RCU) box . . . fitting name, eh?!  The first relay to go in was the clear cased 3 pole Auto Extension (AE) relay, RL000.  It handles the actual engagement of the gear Auto Extension feature and also is a pass-thru for all the major electrons running the gear up or down.

I ordered this relay specifically with bottom mounting tabs, with the corner of the left tab needed trimmed diagonally just a hair for it to fit properly.   It mounts with a 4-40 screw on each side, each coming in externally from the back.  All the mounting screws coming in from the back side are countersunk to allow the back surface of the box to remain flat, which facilitates ease of mounting the box to the aft side of the Napster bulkhead.

Next relay up to get mounted inside the box was RL003, or the AX relay.  This relay is the one I added back into the mix that charges the small 1.2A backup battery that was provided in Jack Wilhelmson’s original design.  Relay #3 takes control of the system in case of a power emergency to drop the gear down using the 1.2A backup battery for power.  In Marc Zeitlin’s new gear wiring design he doesn’t use this relay since his system incorporates a manual (ratchet) drive for emergency gear extension.

Finally, as for relay #3, I mounted this guy first since it has a unique feature that needed to be dealt with that the other two black relays don’t: down along the top side of the relay is the RXEF-250 wafer style fuse soldered into place that’s used during backup battery charging.  Getting under this fuse to install the K1000-6 nutplate would have been a lot more difficult if I couldn’t get in from the side (where the other two relays sit) to mount the nutplate.  After I mounted this relay, I put some double sided foam sticky tape underneath the wafer style fuse to keep it mounted to the front of the relay for anti-vibration.  I also tipped the box right side up and glopped some E6000 adhesive (yep, the stinky stuff) onto each edge of the fuse to keep it secure to the relay, banned the box outside on the deck for a few hours while it cured and I took off to run some errands.

Upon returning from my errands (which included buying parts for the flexible sander Nick Ugolini describes how to build on his blog) I installed the last two relays: RL001 & RL002 [Note: Simply for space I truncated the relay IDs and labeled them on the actual relays with RL0, RL1 … etc.).  As you can see, these two relays simply control gear up and gear down, respectively.  All went well except for the life of me I couldn’t find a 6th K1000-6 nutplate to use on the top side flange of RL002.  After searching for a good while, and simply not finding the pack of 23 I show having on hand (simply maddening!), in order to get this thing wired up tonight I improvised, adapted and overcame by using an aluminum binder stud, cutting off the top and then quickly Dremeling a not-so-pretty slot for a bladed screwdriver.  I doused it with a good measure of blue Loctite and in it went… Voila!

Here’s another shot of my mounting improvisation . . .

Over the next couple of hours I confirmed & verified the wiring in this box matched exactly what was on the diagram.  Having had to pull all the terminals off their posts, I used a pair of channel lock pliers to compress the terminals just a bit to ensure their clamping pressure was nice and tight.  I then slowly replaced all the terminated wiring back onto the relay posts, performing a continuity check as each set of wires went back in.  After all the wires were back in place, I zip-tied them into place to ensure no wires would be vibrating and wreaking some future electrical havoc by gnawing through a neighboring wire, etc.

Here’s just a closer shot of the internal RCU box wiring . . .

I then cut & terminated all the wires with AMP CPC sockets.  Again, as I finished each wire I performed a continuity check to ensure all was electrical good on that wire circuit from source to connector.

With all the RCU box wiring set to be terminated into the AMP CPC connector, I called it a night.  I may have actually done a bit more but it was quite late and I was collaborating online with Marco (who was in Hawaii for work!) on the specs for the AEM box.

 

Chapter 22 – RCU Box & Brackets

I didn’t get the intermediate steps documented since I’ve been out & about this weekend with friends.  Here is the final result of the Clickbond mounting for the Nose Gear RCU box.  Again, I used 3 plies of BID along the top row (2 Clickbonds) . . .

. . . and 3 plies of BID along the bottom row (3 Clickbonds).  After curing, I pulled the peel ply and cleaned up the goobers.  Thus, the RCU box is officially mounted.

A little sideline tasker I completed was to drill and flox in place this Adel clamp for the Throttle electronics cable that terminates into the P4 Connector.

After pre-drilling the 4 screw holes and the 8 holes for the K1000-6 nutplates, I then did a final trim & sanding on the Dynon Intercom bracket.  I determined where its position needed to be and marked the sidewall.  I then 5-min glued the intercom bracket to the sidewall.

I then laid up 2 plies of BID (pre-pregged of course!) on the top side of the intercom bracket, and peel plied it.

I pretty much followed the same steps for the Throttle handle electronics cable P4 connector bracket just forward of the instrument panel on the left side.  After 5-min glueing it to the wall, I laid up 2-plies of BID and peel plied it.

These tasks above are all on a list of 10 electrically-related items that I want to have finished before I move on to the wheel pants.  Once these brackets and the RCU box wiring are completed, I’ll be down to about a half-dozen items on the list.

 

Chapter 22 – Mounting Gear RCU box

Today I received the Nose Gear RCU box in the mail from Marco.  He did a great job and the relays fit perfectly!  A little too perfectly actually . . . The holes are aligned exactly as I designed them in CAD, except I put them in a little too close to the end wall of each relay so that I won’t be able to fit a normal aviation/MIL-SPEC nut on the screw.

After thinking about this issue a bit I realized that the answer was fairly simple: nutplates. Nutplates are narrow enough that they’ll fit and even though a bit higher cost solution than normal AN nuts, they’ll definitely do the trick.

With the relay mounting issue out of the way, I prepped the box to be mounted with 5 Clickbonds.  The mounting holes’ diameter were just slightly narrower than designed, so  I spent a few minutes drilling those out to size.  I then taped the back side of the box with clear packing tape.  After roughing up the back sides of the Clickbonds with sandpaper, I cleaned them with Acetone.  I then mounted them in the box, whipped up some 5-min glue and put a good dab on each Clickbond face.

I then mounted the box on the aft side of the Napster bulkhead aligned with some position marks that I had previously made.  I held the box in position for a little over 5 minutes to let the 5-minute glue cure.

With the 5 Clickbonds attached to the aft face of Napster I pulled the RCU box off of the bulkhead.  The Clickbonds set well and the attachments were solid.  I cleaned up some of the 5-min glue gunk and left the Clickbonds alone to fully cure.

While the Clickbonds cured, I measured out the dimensions I would need for the BID tapes for the top and bottom row of Clickbonds.  I wanted at least a good inch from each Clickbond stud to hold it securely in place.  I cut 3 plies of BID 2″ high and with a slight angle for the outboard side of the upper row, for a total of two sets of 3-ply BID.  I then configured the BID plies in plastic for pre-preg setups and called it a night.

Chapter 22 – March Madness Brackets!

Well, My March Madness brackets!

Today I started working on the brackets for both the P4 throttle connector bracket and the Intercom bracket.  As for the Intercom bracket, I decided that I’ll most likely make the right pilot armrest removable to gain access to intercom wiring.  So the intercom mounted in the bracket will remain on the sidewall, allowing the armrest to be pulled away from it.

I started off by determining the dimensions of each bracket, and then marked up a 1/16″ piece of G10 with these dimensions.  I then drilled the 1.5″ hole for the Throttle P4 AMP CPC connector.

I then cut the rectangular hole for Dynon Intercom.

And then test fitted both the Intercom and the P4 connector, with both fitting just fine.

After prepping the holes I took the evening off to go to dinner.

Chapter 22 – Cables, cables, cables

Today’s post is just a quick update showing some cable builds.

First off is the 3-wire braided cable for the Nose Gear Auto Extend laser altimeter.  These three 22AWG wires will provide power, ground and signal path from the laser altimeter into the Auto Extend Module (AEM).

After terminating the wire ends with mini-Molex pins (above) I then inserted the pins into a connector body.

I also soldered 2x 22AWG wires to a 9-pin DSub connector to make up the connector that all the panel components that require an external dimming control will tie into.  The black wire with the DSub pin is a ground wire to the avionics ground bus (G5) for the dimmer module shown at the bottom of the pic below.

Finally, although I didn’t make this cable, I thought I’d show it just to hint at a bit of progress on the GPS navigator install front.  I ordered a 12′ RG400 cable with a TNC connector on one end (mounted to the GPS antenna in below pic) and a 90° BNC connector on the other end.  Since I only need around 6′ for the GPS antenna, I’ll use about half of the RG400 cable and the BNC connector somewhere else.

That’s all for now folks!

 

Chapter 22 – Wiring AEM components

Today I finished wiring all the components of the Nose Gear Auto Extension Module (AEM) as far as I could without having the physical box in hand.  As I’ve mentioned before, the AEM is simply an upgraded replacement of Jack Wilhelmson’s Nose Gear AEX system that utilizes Marc Zeitlin’s design to incorporate a few more parameters into the Auto Extension system to pretty much eliminate annoying false-positive situations and ensure that really the only time the AEX will deploy the gear is on final approach when you actually forgot to put the gear down.  To make the magic work, Marc added another airspeed switch (for a total of two), a throttle mounted “microswitch,” and a laser altimeter.

I decided to cram all this new stuff into a box approximately the same size as the original AEX box.  Since Marco is 3D printing this one as well, it will have holes ready to go for mounting the internal components and some external mounting flanges for attaching the box to the forward side of F22 with Clickbonds.

The laser altimeter operates on 5 Volts, so it requires a 12V-5V converter.  However unlike Marc Z. I chose to mount the converter up front versus the way he did right next to the laser altimeter (which is on the belly near the main gear).  There is no right or wrong here regarding the location of the voltage converter, I just simply wanted to drive the weight forward and also hide the converter away in the AEX box.

In between the voltage converter (right, below) and the airspeed switches (left, below) are two relays.  These relays are unique to my specific system since these are the ones I needed to wire into the mix if I wanted to continue to use my throttle-mounted toggle switch to control the nose gear up/off/dn.  These relays are fairly small and light, although robust, so the weight penalty is negligible.

Finally, in each pic I show the 15-pin DSub connector.  In the very top pic, and the one below, you can make out the black bar that depicts the hole for this DSub connector on the actual-sized box CAD diagram lying below the components

As with my RCU components, the only thing left to do with these are to physically mount them into the box and then cut & terminate the wires with DSub pins.  I do have a few minor tasks that I can complete for the final prep of this system before I have boxes in hand and am ready to install.

 

Chapter 22 – Gear RCU Wiring

Today I finished wiring all that I could on the Nose Gear Relay Control Unit (RCU).  My first task of course was to trim the lengths of the cross connect wires to the outboard relays (#1 & #3).  I then re-terminated the wires with new red FASTON terminals and double checked that all was good with those.

I then started cross-connecting wires from the 3 lower relays (black) to the top AEX relay (clear).  One of the big challenges, which I think is a bit analogous to solving a puzzle, is to take the logical wiring diagram on paper and determine how the wires and components actually hook together in real life.

What looks like a long wire on the page can of course be no wire and simply a lead to a diode or resistor.  Such is the case with the RXEF250 Minifuse that looks like a brown wafer overhanging along the top side of relay #3.  Although on the diagram this shows up in the middle of wire run, in fact this Minifuse IS the wire run.  The diodes at the bottom of the relay connections in the pic below is also pretty much the same way.  On the diagram it looks like 3 diodes suspended mid-point in wire runs, when again they are the wire runs, all starting out at the AEX relay coil’s negative post.  Out of 3 diodes hooked to the coil post, only one them is physical attached to a wire, while the flyback diode is terminated with the positive power wire, and one is simply a loner heading off by itself to a Common terminal.

The wires going every which a way again will get corralled, secured and terminated into the 19-pin AMP CPC connector.

Speaking of connector, here is the AMP CPC connector for the gear RCU.

And a shot of the aft side of each connector half.

Besides physically mounting the relays, double checking the wire terminations & cross connects are correct and the terminals are attached tightly, the only thing left to do is to cut the wires to length and terminate the ends to fit into the connector.  Thus, on to wiring the AEM!