Flap Position Sensor Installed (2/8/13)

3.0 Hours –

I finally received all the parts I needed to install the flap position sensor, so this became my main goal for the night.  The sensor is the Ray Allen POS-12.  It is just a box with a free-moving arm that can extend 1.2 inches.  The movement of the arm gets converted to a signal that is sent to the avionics.  My challenge is to link the sensor’s arm to the flaps in a way that full movement of the flaps is translated into 1.2 inches of travel on the sensor.

Not wanting to re-invent the wheel, I installed the sensor in a way that seems to be the most common among RV builders.  The sensor itself is attached to the forward side of the back rest brace.  The sensor is then connected to the flap weldment using a cushion clamp, some threaded rod and a couple of clevis ends.

First, I cut the threaded rod down to about 9 inches and then attached the clevis ends.  Both the rods and the clevis ends I used were 4-40, and purchased from a local hobby shop’s aviation section (RC plane parts).  One end attached directly to the sensor, and the other end was attached to the flap weldment using a bracket I made and a cushion clamp.  The cushion clamp was positioned on the flap weldment arm that goes to motor about 1/2 inch forward of where arm meets the main cross member of the weldment.  Once the clamp and sensor were attached to the weldment, I ran the flap motor until it was fully retracted.  I then manually retracted the sensors arm and positioned the sensor on the back rest brace.  With the position of the sensor set, I removed the back rest brace, drilled the sensor to the brace, and attached it with two #4 screws and stop nuts.

It still needs some finishing, but this is the backside of my bracket that will attach the position sensor’s pushrod to the flap weldment. This was a piece of angle, but one side was almost completely removed. Only enough is left to keep the bracket from rotating.

The front side of the bracket.

The complete flap position sensor setup. The clevis ends are RC parts from the local hobby shop, and they fit the sensor’s arm perfectly.

Once fully assembled, I ran the flap motor a couple of times to make sure the sensor could travel freely, and extend/retract fully.  The first run wouldn’t allow the sensor to fully extend, so I had to re-position the cushion clamp further aft and shorten the pushrod slightly.  After a little experimentation, I had everything dialed in.

In the flaps up position, the sensor’s arm is fully extended.

Flaps down, the sensor’s arm is retracted. The picture makes it look like the pushrod is right up against the flap motor, but it is really over an inch away.

Next, I started working on the F-782D angles.  These angles are used to provide additional support to the F-782A cover plates that cover up some of the fuel/vent lines in the cockpit.  The plans make the fabrication of these angles look more difficult than it actually was.  In the end, it didn’t take long to do all the trimming and drilling.

The F-782D brackets are fabricated from some .032″ x 3/4″ x 3/4″ angle. The plans make this part look more complicated than it is.

My F-782D angles after being trimmed and drilled for the holes that will attach the angles to the fuselage. The holes on the other side will get drilled in assembly with the F-782A cover plates.

In order to get an idea of the positioning of the angles, I temporarily installed the F-782A cover plates and marked where they butted up to the sides of the fuselage.  Drilling the angles is going to be a bit of a challenge since access is limited and there is no way to clamp the angles to the fuselage.  Instead, I’m going to try to use some double-sided tape to hold the angles in position while I start drilled.  However, I decided to let this wait until tomorrow.

Flaps Mechanism Continued (1/26/13)

5.6 Hours –

Today, I’m back to work on the flaps…or, more correctly, the flap actuator mechanism.  The entire mechanism is basically a motor that is attached to a couple braces in the fuselage.  The motor is connected to a weldment that is connected to the actual flaps on the wings.  Much like the rest of the plane, its simple and it works.

The first thing I wanted to do was to install the flap weldment.  The side bearing blocks had been fitted to the fuselage much early, so all I had to do was bolt the blocks in along with the weldment.  The F-680 center bearing block needed to be drilled to the floors, but I ran into a problem here.  Although I drilled the block per plans, the forward hole was too far forward.  If I would have drilled it where it was, I would have missed the flange of the F-705 bulkhead.  I’m going to order a new block ($8.70 from Van’s) and try again.  This time, however, I’m going to drill the forward hole slightly more aft than the plans call for.

I drilled the F-680 bearing block per plans, but it doesn’t fit right. The holes are hard to see, but the forward hole is too far forward. I’ll get a new one and drill the hole a bit further aft than the plans call for.

Even though the bearing block didn’t fit right, I was able to use it to mark and trim the baggage tunnel cover.  Once this was done, the tunnel cover was finished, to I prepared it, along with the aft seat floors for primer and paint.

The baggage tunnel cover and aft seat floors are ready to be primed and painted.

Next, I started working on the various braces and brackets that hold the flap motor in place.  Several parts needed to be fabricated from stock, while other parts were already finished and ready for assembly.  Since there was a lot of fabrication work, it took quite a bit of time.  Rather than explaining everything I did, I’ll just let the pictures tell the story.

The first of the flap parts to fabricate was the F-766C bracket. Only one hole is drilled now, the rest are drilled in assembly with the F-766A actuator channel.

The F-766C drilled to the F-766A channel.

The F-758 brackets are riveted to the bottom of the F-766A channel.

The F-766C bracket is riveted to the F-766A channel using flush rivets. I also riveted all the platenuts to the sides of the channel using NAS1097 “oops” rivets.

The F-766B bracket also had to be fabricated from a piece of angle stock. Van’s includes two pieces of stock. I’m not sure if other planes require two, or if they just assume you will mess up the first!

The F-785B bracket must be fabricated as well. It links the F-785A back rest brace to the baggage floor.

The F-767 plate must be fabricated from stock material. It only has to be cut to size and bent. It will get drilled in assembly later.

All of the flap mechanism parts I worked on today.

A closer view of the brackets and spacers for the flap mechanism.

Wings Complete!!! (12/4/11)

2.3 Hours –

The wings are now completely finished!!!  That’s not even one of my usual “finished except for…” lead-ins.  They are now going to sit as they are until it’s time to mate them to the fuselage.  Speaking of the fuse, I received a shipment notice/tracking number from Van’s, and the fuselage is scheduled to be delivered by ABF on 12/7/11.  Great timing!

The fuselage is on its way! If all goes well, deliver should be in three days.

The work I did today to finish the wings was pretty easy.  The first thing I did was to reinstall the left aileron on the wing.  To make this a little easier, I decided to install the push-rod on the aileron while the aileron was sitting on a work bench.  Once the push-rod was attached, I could insert it into the aft end of the wing before positioning the aileron on its brackets.  Once the aileron was positioned, it took a little time to get all the washer/spacers into the correct positions, and I also had to remake one spacer (the original was too short and I didn’t catch it before), but I eventually got everything connected.

I forgot to mention a new tool previously, but I did spend $30 to get a set of washer wrenches from Avery Tools.  They seemed a little expensive for what they are, but they really do make washer insertion much easier.  In my opinion, they pretty much paid for themselves during aileron installation.

The Avery washer wrench set has a total of four wrenches like this one. Each wrench holds two different sizes of washers.

Next, I riveted the pitot mast to the left wing.  The mast attaches with only 5 rivets, but I managed to screw up one of those.  I had been doing great with my riveting, with almost no re-dos on the bottom skins, so I guess I was due.  In addition, as I was working on the mast, I had my first broken cleco.  The cleco wouldn’t stay in the wing.  When I checked it, I found that one of the small “dogs” had broken off.  Unfortunately, this is an unfixable issue.  However, this little cleco had seen a lot of use…you can still see some of the tank sealant on it from when it was used on the fuel tanks.

This cleco gave its life for the cause.

Once the mast was riveted, I routed the pitot/AOA tubing through the wing.  For now, I have it running under the bellcrank.  It looks like it should be fine, but I may decide to anchor it to the spar sometime down the road.

For now, the pitot/AOA tubing is routed under the bellcrank. I may clamp it to the spar sometime in the future.

The pitot mast with the pitot/AOA tubing protruding.

With the tubing in the wing, I decided to go ahead and install the pitot/AOA tube as well.  This was just a matter of pushing the two tubes into the fittings, and then using four #6 screws to attach the pitot tube to the mast.  I had purchased a cheap pitot tube cover, but it is about an inch too short for the Dynon pitot/AOA.  It will function OK for keeping the pitot tube clean in the garage, but I’ll have to buy or make something else once the plane is ready to fly.

The installed pitot/AOA tube...hopefully, there's no leaks!

My cheapo pitot cover is a bit small. I'll have to buy a different one or maybe make one. Of course, the old rubber chicken is always an option!

Next, I reinstalled the flaps on both wings.  With the wings in the cradle, installation of the hinge pins is a bit tricky, so I don’t have them in all the way yet.  I really hope they are easier to install once the wings are on the plane!

The last thing I did was to install the access cover plates on the left wing.  With the covers in place, there was nothing left to do with the wings but try to find a good place for storing them in the garage while the fuselage is built.

Wings...DONE!!!

Left Flap Hinge and Left Nav Lights Completed (7/3/11)

2.7 Hours –

This morning, I managed to get a couple of hours of work in on the RV project.  During that time, I finished attaching the left flap hinge to the wing.  As with the right side, I had to remove the temporary rivets from the skin/flap brace, deburr as needed, then rivet the hinge to the wing.  Once that was completed, I cut the hinge pin in half, bent it to the proper shape, and fabricated another hinge pin retainer.  The flaps are officially done!

Just like the right side...the left flap hinge pin and retainer are finished.

Later in the afternoon, I decided to finish up some wiring tasks on my left nav lights.  I already wired the LEDs together, but I hadn’t yet attached the power leads.  I decided to make the power leads two feet long.  This is much longer than I need, but I would rather have them too long for now.  I’ll shorten them when the tips are ready to go on the wing.  Before I soldered the wires to the LEDs, I drilled a 1/4″ hole in the back plate for a grommet that the wires will pass through.  Then, I soldered the wires to the LEDs, and I’m happy to say that my soldering is getting better (it’s still not very pretty though).  With the power leads in place, I hooked them up to the driver and fired them up.  As usual, I forgot how bright they are and stared right at them as I cranked up the power.  Since the lights are in parallel strings, and the driver supplies 1000mA, each string sees 500mA.  Even in this slightly under-driven state, they’re still brighter than any nav lights I’ve seen on a factory built plane.  Once I remove the protective paper from the mirrored plexi, the mirror should amplify their apparent brightness.

The power wires were soldered to the LEDs, then passed through a grommet. They'll connect to a driver that will be attached to the outboard wing rib.

As a mild test of heat generation, I left the LEDs on for about 10 minutes.  The back plate started to warm up a bit, but it was by no means getting hot.  I had already ordered a couple of heat sinks, and, once they arrive, I think I’ll go ahead and install them on the back side of the aluminum plate just to be safe.

All six LEDs lit up. Very bright...the camera doesn't do them justice.

The LEDs with the mirrored plexi in place. The protective paper is still in place, but I think they'll look even brighter when the mirror is uncovered.

Right Flap Hinge Riveted to Wing (6/26/11)

2.0 Hours –

With both flaps drilled to the wings, I only have some finishing up work to do before the flaps are done.  I decided to finish up the right flap first since it is in a bit more accessible position in the garage.

To start things off, I removed the flap from the wing and deburred the holes in the wing side of the hinge.  Once deburred, I drilled out the temporary “oops” rivets that were holding the wing skin and flap brace together.  Then, I re-clecoed the hinge to the wing and drilled it where the “oops” rivets were located.  The skin side of the “oops” rivets holes were then countersunk for the smaller NAS1097 rivet heads and the rest of the hinge/skin/flap brace was deburred as needed.

Next, it was finally time to start riveting the flap hinge to the skin/flap brace.  I used my squeezer to install all of the rivets.  However, I left the holes where the outboard bottom skin attaches to the flap brace/hinge empty for now.  They’ll get rivets when I rivet the final bottom skin to the wing.

Van’s gives you two options for securing the flap hinge pin.  The first is to cut the hinge in half, remove a few hinge eyelets from the center of the hinge and insert the pins from the middle.  The second is to drill a small hole in the inboard aileron bracket that is slightly off-center from the hinge eyelets.  The pin can be inserted, but, since the hole is off-center, the pin can’t back out without manually aligning it with the hole in the aileron bracket.  Based on what I’ve read from other builders, I opted to go with the first option and use two hinge pins inserted from the center.

To do this, I removed one eyelet from the center of the wing side of the hinge and two from flap side.  This leaves a three-eyelet wide gap where the pins can be inserted.

I removed one eyelet from the wing side of the hinge. Here you can also see one of the "oops" rivets that were reinstalled with the flush head on the skin side.

Two eyelets were removed from the center of the flap side of the hinge.

I then cut the hinge pin in half and bent one end of each pin so that it would lie flat against flap brace.  These bent ends will be captured by a couple of hinge eyelets I cut from some scrap hinge.  The eyelets will then be attached to the flap brace using a #6 screw and nutplate.

One of the hinge pins bent. I used a piece of hinge to see how the hinge/pin would sit against the brace.

Both pieces of hinge pin bent and inserted. Hinge eyelets will be screwed to the flap brace to lock the hinge pin ends in place.

Two eyelets, cut from extra hinge stock, will be used to lock the hinge pins to the flap brace.

Thanks to my wingtip project, which is also using #6 screws and nutplates, I’m short on hardware for the flap pins.  This means I’ll have to finish up the flaps another day and place yet another order with Aircraft Spruce this afternoon!

Left Wingtip and Left Flap Work (6/25/11)

1.8 Hours –

Today, I was able to put in almost two hours of work on the airplane project before the garage became too hot.  I wanted to get some more done on the wingtip nav light project.  There were a couple more things I needed to finish on the left side so that I could bring parts inside to work on the wiring while sitting in the air conditioned house!

I started by drilling and countersinking the mirrored plexi pieces.  To do this, I drilled the openings for the LEDs to #12.  I chose #12 because this is the largest countersink cutter I have.  Then, I machine countersunk the holes.  I don’t think countersinking is necessary, but it sure makes the opening look better.  Once the holes were countersunk, I carefully enlarged them to 7/32″ so that the lenses on the LEDs will fit through the plexi.

The mirrored plexi was easy to machine countersink. The holes were drilled to #12, then countersunk, then drilled to full-size.

Next, I did a little work on the aluminum cutout insert.  I used the plexi piece as a guide for drilling three holes that will be used to attach the plexi to the aluminum with screws.  Once these holes were drilling the aluminum, I attached three nutplates for #6 screws.  I also searched for something that will make an ideal spacer between the plexi and aluminum.  The spacers have to match the thickness of the LEDs.  The closest thing I could come up with was a stack of three rivet washers.  A stack of washers will be placed on each screw so that the plexi doesn’t bed down at the attach points.  Now, I’m ready to start fitting and wiring the LEDs on the left side.

Here's the left nav light temporarily assembled with the mirrored plexi and LEDs in position.

Finally, I turned my attention to the left flap.  The right flap was really easy to drill to the wing, and I was hoping that the left would be just as easy.  As usual, the second time I do something on the plane, it is easier than the first time.  The left flap was aligned and the hinge was drilled in a matter of minutes.  Once again, I had ample edge distance on the wing side of the hinge.  I guess I just don’t understand why so many people have edge distance issues here and have to order wider hinge material.

The left flap after drilling the hinge.

The flaps are both clecoed to the main wing structures now.  All I’ll have to do to finish them is deburr the wing side of the hinge, figure out my method for securing the hinge pin, and rivet the hinge to the wing.

Both flaps are drilled to the wings...now they really look like wings!

Almost all the parts are attached.

More Wingtip Work and Right Flap Installed (6/12/11)

2.5 Hours –

With today’s work session, I passed the 500 hour mark on the build.  This means I’m anywhere from a third to a fifth of the way finished as far as build time goes.

I started the day off by working a bit more on the wingtip cutouts.  I had already transferred the pattern to some sheet aluminum, so I used my band-saw to cut the pieces out.  Once cut out, I did some edge finishing with both a belt sander and a Scotchbrite wheel.  However, I won’t be able to finalize the shape until they are bent and I can hold them in place on the wing.

The left wingtip cutout before bending. I also made one for the right since it is just a mirror image.

Since I had the left wingtip on the bench, I decided to go ahead and attempt to bend the left cutout.  To do this, I simply used the edge of my workbench and a section of 2″x4″.  After a few attempts, I had the angle correct, but the cutout had quite a bit of extra material that needed to be removed.  My belt sander made quick work of this and made it easy to keep the curved edge intact on the aluminum.  For now, I’ll just use the left cutout to work on making the plexiglass pieces and figuring out the LED arrangement.  Once everything is finalized, I’ll come back and finish the right.

After bending the cutout, I had to do a little trimming and finishing to get it to fit correctly.

Next on my to-do list was to get the flaps installed.  Since the right aileron has been neutralized, and the bellcrank jig was still in place, I decided to start with the right flap.  The biggest problem with mounting the flap is that there is a gap between the bottom wing skin and flap brace if no clecoes/rivets are installed.  To eliminate this gap while aligning and drilling the flap hinge, I used a method that I found on a build site called Matt’s RV-7 Project.  However, he gives Dan Checkoway credit for the idea.

The basic idea of this method is to eliminate the gap temporarily by installing several oops rivets (NAS1097).  These rivets will be flush on the flap brace side during initial flap mounting.  Then, before riveting the flap hinge to the wing, the oops rivets are drilled out and reversed so that the flush head is now on the skin side of the wing.  To make this work on my right wing, I ended up drilling holes for 7 oops rivets.  After manually countersinking the flap brace, I squeezed the oops rivets in place, and the gap was gone.  With the gap closed, I could easily set the flap in position and clamp it with two side-grip cleco clamps.

I drilled 7 holes through the bottom skin and flap brace in each wing for temporary rivets.

The flap brace is countersunk for an oops rivet. After mounting the flap, I'll drill out these rivets and re-insert them with the flush head on the skin side.

Two clamps held the flap in position while I adjusted it. Here's the outboard clamp near the aileron hinge.

The inboard clamp was much easier to install and adjust compared to the outboard clamp.

With the flap now clamped in position, I could make small adjustments, nudging the flap inboard/outboard, up and down, until the trailing edge was aligned with the trailing edge of the aileron and there was a 1/4″ gap between the flap and aileron.  Before starting to drill I had to make sure I would have enough edge distance on the wing side of the hinge.  Since I previously drew a line on the hinge indicating minimum edge distance, DO NOT CROSS, it was a simple matter of glancing through the holes in the wing skin to see where the line was.  The line was barely visible at the forward side of the holes, so I had more than enough edge distance.  I was partly surprised by this since I’ve read so many accounts of builders having to order a wider piece of hinge stock in order to meet the edge distance requirement.  I can only hope the left wing works out the same!

The right flap hinge is now drilled to the wing. No hinge edge distance issues here!

The gap between the flap and aileron is a perfect 1/4" the entire length.

Since everything was lined up perfectly on the right flap/wing, I decided it would be good to take a lunch break before drilling the hinge and then return to double-check the alignment with fresh eyes.  After lunch, I remeasured the flap to aileron gap, double checked the trailing edges were in-line, and re-checked that my edge distance would be more than sufficient.  With everything still satisfactory, I started drilling at the outboard end of the flap.  Since the flap was only being held in place by two side-grip clamps on the hinge, and a bigger clamp holding the flap in neutral position with the aileron, I started drilling very cautiously and with very little pressure on the drill.  After the first hole was drilled and clecoed, I, once again, checked that everything was still in the correct position before proceeding to the next hole.  I continued this way for sever holes.  Then, when I felt the flap was sufficiently held in place with clecoes, I picked up the pace ever so slightly.  A few minutes later, the flap hinge was completely drilled and clecoed.  As usual, something I was really worried about working came out great.

Of course, now that the right flap is drilled, I have to repeat the entire process on the left wing.  For today, I managed to install the bellcrank jig and get the left aileron neutralized, and I also installed the 7 temporary rivets in the flap brace and wing skin.  At the next work session, I’ll be ready to align the left flap and drill the hinge.

After a couple twists of the pushrod ends, the right aileron was aligned. The angle isn't on the center of the aileron's trailing edge since it is aligned with the side of the bolts.

Right Flap Final Prep Finished (4/22/11)

0.5 Hours –

Once again, I only spent a short time on the plane. I wanted to finish all the prep work on the right flap and possibly start riveting, but it was just too hot in the garage to keep working.  That’s right, it’s only mid-April, but we are already hitting the high 90’s for our daily temperatures.

To finish the top skin, all I had to do was dimple a few holes.  Most were dimpled with a c-frame, but a few had to be done with my Avery pop-rivet dimpling tool.  After all the holes were dimpled, I clecoed the top skin to the bottom skin/rib assembly and mounted the flap in my v-brackets for riveting.  Hopefully I’ll find some time to rivet the flap during the weekend.

The right flap is clecoed together and ready for riveting.

Another view of the right flap in the stands.

Right Flap Top Skin Prep (4/21/11)

0.7 Hours –

Once again, I only had a short amount of time to spend on the RV project.  No pictures, but I started to prep the right flap’s top skin for final assembly.  I managed to get the edges and holes deburred, and I started to dimple, but I still have a couple dozen holes yet to dimple.  I should have time to finish this up tomorrow.

More Right Flap Final Prep and Riveting (4/17/11)

1.0 Hours –

I only had a little time this morning to work on the plane, so I didn’t make a lot of progress.  If you add up the hours, I really haven’t spent that much time on the flaps, but they are starting to feel like a never-ending sub-assembly.  At least I was able to rivet a few things together today.

I wanted to get a few parts off the workbench, so I started off by riveting the FL-706A angle to spar.  After that, I also riveted the FL-706B plate and nutplate to the inboard rib.  Both of these assemblies are easy to rivet since all the rivets could be squeezed.

The FL-706A angle is riveted to the right flaps forward spar.

The FL-706B plate and nutplate are riveted to the inboard rib.

Next, I deburred and dimpled the bottom skin.  With the bottom skin prepped, I could rivet the aft ends of the interior ribs (and shims) to the aft spar.  Again, these rivets could be squeezed.

After preparing the bottom skin, the aft ends of the ribs are riveted to the aft spar. All other rivet holes are left open for now.

Another view of the aft end of the ribs riveted to the aft spar.

At this point, all that remains is to deburr and dimple the top skin, then rivet everything together.