Tips and Techniques
This page will be updated constantly as I learn new techniques worth sharing. Please check back often.
Making the Slider Canopy Frame Fit (February 22, 2008)
After building a 9A and helping several friends make their sliding canopy frames fit, I've done some investigations
First of all, I've talked to Van's about the issue, and they know there is an issue, but the canopy frames are all jig-built and they can't determine why there is a problem with some aircraft.
With the help of a friend, I did a survey of some local RV's with sliders to determine if the fuselage was the big variable. In short, the answer is YES.
Here's some examples:At roll
bar At top aft skin/longeron intersection.
1. 42 3/4 " 40 11/16
2. 42 7/8 " 40 7/8"
3. 42 1/2 " 40 7/8 "
So it appears that there is quite a bit of variation (up to 3/8") at the roll bar position. This makes sense, because this dimension is not controlled very well during construction.
I've seen some folks with narrow fuselages have to bend the roll bar (quite a task), but the canopy frame fits well. The opposite is also true-- those that don't have to bend the roll bar have to cut and weld the canopy frame (as I did). These 'wide' fuselages also have large fish-mouths in the aft part of the canopy tracks where they need to be trimmed flush with the fuse.
So, based on my experience, here is a method for making the canopy frame adjustable for a perfect fit.
Making the Slider Canopy Fit - VAF Forums
Fix for unstable voltage regulation using Van's externally regulated alternator/regulator (Jan 6, 2008)
Here's the fix for a pulsating alternator output, noticeable by flickering panel lamps and/or noise on the intercom and radio. The relay K3 is inserted into the regulator BUS circuit. Wire the B+ connection directly to the alternator output, the FIELDIN connection to the master switch field circuit, GND to firewall ground and FIELDOUT to the voltage regulator BUS input.
By connecting in this fashion, most of the voltage drops between the alternator output through the master bus, master switch and Bus wiring are eliminated. Flight testing shows a rock steady master bus voltage and no pulsating panel lamps or radio interference.
D1 is a snubber for the relay coil that protects the master switch, and D2 is secondary overvoltage protection that will blow F1 if primary overvoltage protection fails. The primary overvoltage protection circuit is aircraft dependent and not shown.
Here's as simplified application circuit. In this drawing the relay is K3 and the diodes are D16 and D17. D17 is not really required with the primary overvoltage protection crowbar (VR1 - OVM-14).
Getting Down/Slowing Down (flying tip)
The 9A is so efficient that many have trouble slowing down the airplane and losing altitude at the same time. A former bush pilot suggested that use high speed forward slips to do this (speeds above Vfe). I've tried this and it works. It takes a lot of rudder force, but it bleeds off enough energy so you can lose altitude without gaining speed, or lose speed without gaining altitude quickly, or combinations of both.
I'd recommend the forward slip as standard practice to steepen approaches. The 9A flaps are not that effective in adding drag. Try it, you'll like it.
My A-series Skidplate Design (December 17,2005). Update Aug. 27, 2006
There has been much debate over Van's nose gear design. Several A models have flipped over, and there is concern that the nose cone catches a rut or hole, then collapses into the tire, suddenly stopping the wheel. This transfers a lot of force (moment) to the nose gear, which bends. This bending causes the big castor nut to dig in. Once this happens, the nose gear collapses and the airplane flips.
I've designed a skid plate that, in theory, will mitigate this tendency.
The original design (below)was to pack a fiberglass skidplate into the space between the nose cone and gear weldment. The resultant forces due to catching the nose fairing in a rut would tend to push the nose gear up and prevent the collapse of the nose cone.
The result was less pretty than the design, and I used epoxy resin rather than polyester.
It's also necessary to cut out around the big nut to allow the gear to swivel freely. The cotter pin tends to catch, as do the points of the big nut.
The original lay-up was done by packing the flox/resin mix inside a plastic bag, and compressing this between the nose cone and landing gear fork. When set, it was removed, trimmed and glued into place on the nose cone and held in aligment by reattaching the nose cone. When this hardened, I filled some of the wrinkles and gaps on the fork side and repeated the moulding process (sprayed oil on the fork as release compound).
I'm sure there are better ways to do this, and to get a prettier result, but I'm satisfied with what I achieved. I hope to never prove it's value, but if the bottom of my nose cone gets a good grind and I don't flip over, I'll let you know.
** Update. Well, I ground my nose cone bottom several weeks ago in a pothole at the airport, but it did not collapse. Damage was mostly cosmetic, but I'm sure it would have been much worse without the skid plate. A friend of mine did the same thing a couple of weeks ago, and his nose cone was substantially damaged (partially collapsed and punctured by the big nut). He does not have a skid plate.
I consider my 'test' of the skid plate to be successful.
My method of aligning the landing gear fairings on my RV-9A (Feb. 5th 2005) (Also Published in RVAtor).
I believe it's applicable to
all RV models that have wooden gear dampners installed. It also
assumes that the fuselage has previously been leveled in the
flight position.
After riveting the hinges to the fairings, I installed the
fairings and did a rough alignment to the center line of the gear
legs. Then, I marked three points on each fairing trailing edge
about 12" apart at the top, bottom and middle. I carefully
measured theposition of the marks with respect to a plumb line
from the fuselage center and their height above the floor.
I clamped old hollow-core doors to a plank mounted to the aft
fuselage (in place of the HS). These doors were big enough that I
could mark the three positions measured relative to a plumb line
on the aft fuselage and the floor. I then ran three loops of
twine, as shown in Figure 1. These 'streamlines' allow the
adjustment of the fairings accurately in three places.
Now, here's the trick. Once I had alignment of the fairing, I
then drilled two 3/32" holes all the way through the fairing
and wooden gear stiffener, being careful not to drill into the
gear leg. I drilled one hole at the top, and the other at the
bottom, where they will not show later. Into these holes, I put
long AN-426-AD3 rivets to pin the fairing in four places. I
couldn't use clecos because they would distort the fairing. I
improved on this later by cutting up the shaft of a broken
3/32" drill to make pins about 2 inches long.
With the pins in place, the fairing is locked into the optimal
position. I removed the fairings, added e-glass reinforcement to
the hose clamp finger area, and a couple of dollups of flox at
the top and bottom insides of the fairings. Finally, I wrapped
the gear legs in plastic wrap and installed the fairings, hinge
pins, the special locater pins top and bottom and tightened the
hose clamps. The e-glass and flox cured and provided nice
sure-fit fairings.
Now, it's easy to build the intersection fairings and ensure the
gear fairings don't wander about where they are not supposed to
go.
Streamlines.
Closeup of streamlines attached to door.
Drilled holes through fairing and gear leg stiffener and pushed long rivets in as pins.
Here, I used 3/32 x 2" pins that went all the way through.
These pins lock the fairing into position.
A blob of flox on the inside provided further keying to the gear leg.
The $0.50 stick grip (November 28,2004)
I wasted $15 on a rubber stick grip that I purchased from Aircraft Spruce. It wasn't stiff enough to mount switches on and I decided to look around for a nice grip that would take two switches. Well, there seems to be two types: simple rubber 'bicycle style' and F-18 fighter style. Not a lot in between.
Let's face it, I'm not building an F-18, so I got a flash of inspiration. I built my own switch grip in about an hour and for less than $0.50 worth of plastic conduit. It actually cost me $5.00, but I had to buy 10 feet of conduit when I only needed eight inches. The switches are easy to mount and service later, and the position of the grip is easy to adjust (up/down or angle).
I bent this up by heat forming 1" PVC electrical conduit with my heat gun and seaming pliers.
First, I used my rotary tool to cut about a 4" slot down the conduit, then I warmed up the end with a heat gun until it was pliable to the touch. Then, using my fingers (ouch) and seaming pliers. I shaped the grip as shown. After some adjustments and drilling for the switches, it was mostly done. I duburred everything with my plexiglass edge scraper.
Don't worry I'll use better switches, these are just photographic props!
At the bottom end, I cut a slot with my bandsaw, then warmed it up with my heat gun. When it was pliable, I used a Crescent wrench to flare the end in two places. I'll use a hose clamp to secure the grip on the stick, and the the flares prevent the hose clamp from working loose and falling off. UPDATE: a big hose clamp is kind of ugly, so I think I will drill and tap two screws into the stick/grip assembly, once the exact fit has been finalized.
After everything is mounted, I'll wrap it all with handlebar tape (a cloth tape used by cyclists) to give everything a nice texture.
It's easy to see that you can make the business end of the grip as big as you want to hold switches, but they all need to be thumb actuated. I think a little bit more engineering, and you could mount switches on the sides as well.
How useless is fiber optic lighting? (November 19,2004)
Ok, here is my rant: I purchased fiber optic backlit Labels and a fiber optic Post Lamp from Aircraft Spruce. They come from different vendors, but can be connected to an illumination source from either.
Firstly, let me say that the backlit Labels are a fantastic product... they really solve a thorny problem cost effectively. The problem that I had is that I melted right through the fiber tails on one label strip with my hot air gun. The instructions give a vague warning, but provide no indication of the disaster that will happen if you use even a little too much heat on heat shring tubing. I had to reorder my label for $30.00.
Secondly, the Post Lamp looked like a reasonable product, well made and easy to mount. However, the fiber tail is unprotected (no sleeving), so you should slide on a piece of poly tubing. More significantly, I spilled a tiny drop of thread locker on the fiber, and poof! the fiber melted off. Another $30.00 down the drain.
I'm an engineer, and I have a professional opinion about this. It is common practice to use heat-shrink tubing and thread locker in the construction of an avionics panel. It makes no sense to sell a product that is vulnerable to these common installation techniques. In addition, it is unforgivable to provide a fiber bundle without a protective sheath.
More importantly, the products should use chemical and heat resistant fibers, such as glass, not plastic.
In my opinion, both of these products would have been better if they actually had the illuminator LED permanently mounted directly where the fiber tails exited the device. Then, you could just wire in the products using conventional wiring techniques, and not have to worry about handling fiber tails. This would slightly impact the flexibility of mounting, but make them much easier to handle. LEDs can last 100,000 hours, so this should not be a maintenance problem.
I will now purchase LED or incandescent post lights and
avoid more fiber hassles.
IMHO.
Configuration of EFIS D10A and Garmin GTX 327 (September 2004)
Set the EFIS D10A to serial interface mode #4, and set the GTX 327 RS-232 channel 1 input to 'ICARUS ALT'. Test the connection by powering up both units.
Configuration of GPSMap 296 and Digitrak autopilot (September 2004)
Set the GPSMap to NMEA IN/OUT, and set the Digitrak to 4800 bits per second. Test the connection by powering up both units. GPS must be receiving valid satellite data to perform this test. Simulation mode will not work.
Saving the weight and cost of a backup battery for the Rocky Mountain Micromonitor (August 30 2004)
I wired the switched power output of the Dynon EFIS D10A
to the Aux Battery position on the Rocky Mountain Micromonitor
(with the internal charging circuit disconnected).
This allows the internal EFIS battery to power the engine
monitor. Coupled with the internal battery of the Garmin
GPSMap 296, this means that my primary flight instruments, engine
instruments and Nav instrument can all operate in the event of a
power failure. With my hand-held comm on board this will
allow the ability to safely get down to debug the primary
problem.
Saving the weight and cost of a backup battery for the Rocky Mountain Micromonitor (August 30 2004)
I wired the switched power output of the Dynon EFIS D10A to the Aux Battery position on the Rocky Mountain Micromonitor (with the internal charging circuit disconnected). This allows the internal EFIS battery to power the engine monitor. Coupled with the internal battery of the Garmin GPSMap 296, this means that my primary flight instruments, engine instruments and Nav instrument can all operate in the event of a power failure. With my hand-held comm on board this will allow the ability to safely get down to debug the primary problem.
Modification to the Micromonitor. Connect the
Micromonitor External Backup Battery (pin U) to the Dynon EFIS
D10A Switched Power Out (pin 12).
Garmin SL-40 output impedance. (July 26, 2004)
The Garmin documentation does not explicitly call-out the output impedance of the headset circuitry in the SL-40 (and SL-30, I assume). I turns out to be about 100 ohms or less, and cannot be directly tied to the headset bus of a Sigtronics SPA-400 intercom or similar installation.
In my aircraft, I have the headsets, SPA-400 intercom, SL-40, a Monroy ATD-300, a portable radio and a Micromonitor engine monitor all tied to the headset bus. When I tested it, the intercom levels were very low, and the radio was very loud. Turning the radio off fixed everything, but with it on the problems started.
The fix was derived from a Sigtronics app note on their
web site. I added a 511 ohm resistor in series with the
SL-40 headphone circuit output, and everything worked fine
thereafter.
Drilling for snap bushings in tight places (February 10, 2004)
This works well for running wires under the seat ribs, when you don't have a complete set of threaded drills. Using an angle drill, first drill #30 pilot holes, then, using a #30 countersink, drill ('countersink') all the way through the rib. This leaves 1/2" holes, perfect for SB-500 snap bushings.
Inserting hinge bolts (January 24, 2004)
Use a pair of 3/16" Allen wrenches to temporarily pin the Elevator (or Rudder) hinges. They are much easier to slip into the hinge brackets and hinge bearing than reaching in with the bolts while holding the elevator in place. Once both Allen wrenches are installed, slide in the bolts while pulling the respective Allen wrenches out.
Drain hole fairings (January 24, 2004)
These drain hole fairings are bent out of 0.025" Aluminum sheet and are epoxied to the bottom of the fuselage to cover the drain holes. This prevents engine oil from seeping into the drain holes and creates a slight vacuum during flight to pull water (or leaking Avgas) out through the holes. I used T88 structural epoxy to attach the fairings after scuffing, etching and alodining the corresponding areas on the fuselage bottom. The narrow end points forward!
Drilling ribs for snap bushings (January 10, 2004)
To Install the AOA air line for the Dynon EFIS, I mounted a Gretz Aero pitot base. I plan on running two aluminum or plastic tubes through snap bushings on the forward part of the main ribs. One hole is already punched to 7/16", and I installed snap bushings and ran one aluminum tube. The second hole needs to be enlarge to 3/8" or 7/16" to allow snap bushings. After much puzzling, I purchased a 3/8" hex-drive drill bit (unfortunately, a 7/16" was not available), and a 12" hex extension bit. I already had a 6" extension, but it would have been better to have two of the 12" hex extensions.
The collar on the business end of the hex extension had to be ground down in diameter from 0.392" to 0.375" so it would fit through the 3/8" drill holes. If I had used a 7/16" drill, this would not have been necessary.
The inboard ribs I drilled as shown in the photo above.
The hex 3/8" drill bit can be fit into a 1/4" jacobs chuck on my small palm drill, thus allowing me to drill the outboard ribs by reaching in as shown in the above photo. I'm glad I didn't install the outboard skin yet. The bracket on the right is for the Gretz pitot mount.
In order to reach the ribs that are underneath the inboard skin, which I had already riveted in place, I assembled my drill bit, 12" extension and 6" extension after sliding in place between the ribs, then chucked my drill onto the extension shaft. After drilling, I reached in and dissassembled the extensions, unchucked the drill and removed everything. This would have been a lot easier if the inboard skin had not been riveted in place yet, or if I had purchased a second 12" hex extension, because the 6" extension used set screws to hold the second extension shaft in place.
Single-handed riveting of RV-9A bottom wing skins (January 4, 2004)
Plan of attack for single-handed riveting of bottom skins. Rivet inboard skin first, clecoing as you go. Some rivets will require a long arm, long bucking bar, or both. Your arms will get sore!
Riveting bottom skins on right wing. Entire job completed without help by careful planning and long arms. Outboard skin is 'rolled' and riveted from the middle out and middle in.
Baggage compartment (November 28, 2003)
Rather than making the entire floor removable by installing tons o'plate nuts, I cut two holes in each panel for access to the seat-belt anchor bolts, future antenna installation, and for internal visual inspections of the belly. I used my instrument panel punch for this, and I will cover with panel blanks later on.
It's best to mount the flap center bearing block plate
nuts to the baggage compartment rib only, and not riveted in
assembly with the floor. In this fashion, it's possible to drill
out the floor rivets, release the center block and slide the
floor out without removing the flap actuator assembly to gain
access to the rivet heads. I learned this the hard
way. Note that the forward nutplate (on the right) is
mounted with flush blind rivets.
Fuel Pickup Anti-Rotation Bracket (September 1, 2003)
Such a simple part, so hard to make! On the left wing, I screwed this part up once, then got it right the second time. On the right wing, it took five attempts! First lesson: don't work on the airplane if you've had a fight with the wife or kids. Second lesson, follow the technique below:
1. Make the bracket 1-1/8" wide, not the
1" shown on the plans. This leaves more room for error
in step 5.
2. Drill the large pickup elbow fitting hole first
(pilot drill #30, drill to final size with a Unibit). Adjust the
position if you've made the bracket wider (step 1), so that it is
centered fore-aft.
3. Test fit with the fuel pickup elbow in position on
the baffle. You may have to file the hole a bit to get it
to fit properly (elbow is sitting flush on the baffle).
4. Once you are happy with fit; cut the top of the hole
out to make a slot, rather than a hole. This will simplify
assembly later.
5. Now, carefully position the bracket on the end
baffle with the pickup elbow in place. Clamp it securely,
then backdrill the two #30 holes. Deburr and you are done
fabricating the part.
Drilling out rivets (July 26, 2003. Amended October 27, 2003)
Rather than using a full-size drill (#30) to drill out 1/8" rivets, use the following method. First, using a smaller drill (for example, I use a 3/32" or #40 drill for an 1/8" rivet), drill a pilot hole almost through the rivet. It's easy to keep this pilot hole centered on the rivet head. Then, using a full-size drill (a #30 in this case), drill just deep enough to snap off the head with a 1/8" punch. Finally, Use a 3/32" punch and a hammer to tap out the rivet. In this fashion, there is no danger of enlarging the rivet holes by mis-drilling. Drilling through the shank with a smaller drill relieves the interference in the hole, making the rivet easier to punch out.
It is also a good idea to purchase a 12" #40 drill to help in drilling rivets in tough to reach places.
The benefits of this technique are that it makes the rivets much easier to punch out, preventing distortion or damage. It's possible to insert the 3/32" punch in the pilot hole, and have it stay in place 'hands-free'. This frees one hand for a hammer and the other to hold a support block behind the rivet.
Attaching Leading Edge Assembly to Spar (May 9, 2003)
It's difficult to set the rivets holding the leading edge ribs to the spar. You can squeeze some through the lightening holes, and drive most of the others. One tip I learned from the Vans Airforce website is how to help ensure that the ribs sit flush to the spar during riveting: Slip a rubber grommet over the exposed tail of the rivet. The bucking bar will compress the grommet, squeezing the rib to the spar as the rivet sets. Works like a charm, but I found that once partially set, you need to take the grommet off to finish setting the rivet.
Countersinking Spar for Nutplates
I tried two methods:
1) Using an aluminum box-section as a back-plate during
countersinking for both the rivets and the #8 dimpled skin; and
2) Countersinking for the rivets directly (no backplate),
followed by riveting the nutplates in place, then countersinking
for the #8 dimpled skin.
Observations:
Method 1 is more work, and the #8 holes can get misaligned.
Method 2 provides better aligned #8 countersinks, but you must be careful about the countersink chattering. A variable speed drill is useful: use high speed after a low speed chatter, and low speed after a high speed chatter. Once the countersink is nearly complete, the chattering subsides and the result is good. By the way, Van's recommends #2, and so do I.
Method 1. Cool photo, but don't do this.
Wing Stand
Van's plans show a wing cradle constructed from 2x4's and plywood. A better solution is to use the large shipping crate, attach casters to the bottom and shape the ends as required to cradle the wings (like on the plans). Saves a trip to the lumber yard and the box shell can be used to store a lot of the wing parts.
My setup, with HS storage.
Bucking Bars for Tight Places
I polish all of the flat surfaces on my bucking bars, to make them more useful. For tight places, sometimes I duct tape two bucking bars together. This works a lot better than I thought it would.
Trimming Lead Counterweights
To make fine adjustments in the fit of lead counterweights, use a hammer and tap into shape. The lead is quite malleable and can easily be formed this way.
Tight Lies Dimpler (amended September 3, 2003)
After struggling with dimpling the aft holes in the Rudder top rib, and looking at how Tedd McHenry has solved the problem, here is what I did:
I purchased a 'Pop Rivet' dimpling tool, which consists of a small male and female dimple die set with holes drilled in the center. Normally you'd insert one of the supplied nails into the hole, and use your pop rivet tool to squeeze the dice together and form a dimple. The problem is, you can't get the nail into the holes in these tight places.
My solution: purchase a wing nut #40 Clecoe or
Kwik-Lok fastener, and use this to squeeze the pop rivet dimple
dice together. You may have to use a couple of wrenches for
good measure to tighten the fastener, but it works well, and is
cost-effective. **Caution- do not overtighten or you will
break the wing-nut Clecoe!** The pop rivet dimpler is $12.50 at
Avery; and the wing nut Clecoe is $3.25 at Avery or $2.75 at
Brown. You can use these tools in many other places.
Trim Tab Bending Block
After messing up my first trim tab, I built a more elaborate bending block from a length of dense (i.e. hard) 2x4. The hardboard gussets are attached to the top block only (red lines indicate the shape of the bottom block). The bottom block is attached with wood screws to the top block. Drill out the holes for the screws so that the bottom block floats free until the screws are tightened down. Note: my gussets were a bit big, hence the notches.
Insert trim tab skin, tighten screws, clamp the whole works to your workbench tightly and carefully bend the tab down. Don't bend the opposite tab up... reverse the apparatus and the tab and bend it down. This way you only bend against the 'sharp' edge of the cut-out.
Bending Block Top View (above)
Bending Block Bottom View (above)
Wire Marking System
When a number of similar parts need identification, here is a simple wire marking system I have employed. Prior to stripping the protective film and/or cleaning with some kind of solvent which usually (should) remove any Sharpie pen markings that identify the parts, I attach aluminum wire loops to identify the parts and their orientation. Here is the coding I use (yours may be different... make sure you write it down!). This system can be interpreted after priming, unlike paper tags or pen markings on the part. The aluminum is easy to cut off, and won't promote corrosion. You can also use the loops to hang up the parts for priming or making wind chimes (or both), if desired.
You can enhance this system to your own needs, as required. It's very useful when you have prepared a number of similar parts that need identification prior to cleaning and priming, such as my batch construction method described below.
Update, November 28, 2003: If I were to do it again,
I'd just mark the parts by scratching an identifier into the
alclad with the tip of a needle file. Shows through the
primer and is faster.
Construction.
After building the HS, I decided to prep all of the other subkits in the empennage before priming them all at once. This is a long time between driving rivets, but I think it is more efficient that way. In addition, it allowed me to place a combined order to replace all of the parts I screwed up (and one of them Van's screwed up).
After priming, then it's just a matter of assembling, riveting and fitting subassemblies together. After completing the HS, my planned completion order is:
Note: since the Trim tab, Elevators and Rudder all
need Pro-Seal during assembly, the plan is to complete these to
the point where the Pro-Seal can be mixed once and used on all of
the subassemblies where required. At least, that's the
plan.
HS Jig cradles. The positions
indicated in the instructions will allow the center of the skins
to bow out, making match drilling very difficult. As a
result of blindly following the instructions, I ended up having
to drill out some elongated holes to #30 and using
‘oops’ rivets in the center nose rib on one side. The
solution to this is to place the cradles much closer together,
and move the HS structure around as required to pinch the skins
together tight before clecoing and drilling. Alternatively,
I made a smaller version of the cradle jig that I could slide up
like a clothespin around the skins next to the center nose rib
when required.
VS Spars
Dimple, do not countersink VS spars. The instructions
do not specify this, but it is essential to get proper strength.
Deburring/Smoothing Edges. Forget the Scotch-Brite Wheel mounted on your bench grinder for this. Use a belt sander or a long sanding block with emery paper to dress the accessible edges of spars and ribs. I found that starting with a fine-toothed bastard file to take the high spots off, then burnishing the edges, then sanding the edge smooth made quick work of eliminating the shear marks and deburring. Use a burnishing tool for edge deburring (two or three light passes), needle files for inside corners and a regular fine toothed file or sanding block for outside edges. A Scotch Brite hand pad is useful as well if you want to polish up the edges after sanding. Note: The order of filing, then burnishing, then sanding worked best. Burnishing first would make the edges safer to handle when filing or sanding, but the burnishing tool would hang up on the rough spots unless I filed the edge first. I then burnished so I wouldn't cut myself or the sandpaper when the final sanding was performed. The inside of lightening holes goes quickly with a swivel-head deburring tool. Two or three light passes is fine. For smoothing the inside edge of the holes, use a fine sanding drum in your Dremel tool or die grinder. With a smooth arm motion, you can quickly dress these edges.
Update: mounting the Scotch-Brite wheel on a mandrel
in your drill press and building a small table with a semi-circle
cutout to hold the workpiece, you can deburr much faster than the
above technique. I will use this on the wing kit.
Cutting Aluminum Angle I used a miter saw
with a metal cutting blade, and a hacksaw with a new blade to
make short work of this. A bandsaw should work too, if you
get a metal cutting blade. Use a lubricant such as Boelube
to save your blades from wearing down.
Dimpling I removed the protective film
around the holes on one HS skin before dimpling. The male
die in the C-frame dimpler scratched the Alclad pretty good as a
result. On the second skin, I left the film in place and
dimpled right through it. Test fitting of rivets showed
this to be as good or better than the direct method. For the
ribs, I dimpled using a pneumatic squeezer. With the right
rhythm, this can be done in about 30 seconds per rib. Saved
a lot of muscle power over using Vise-Grip dimpler. Some
builders have recommended match drilling dimpled holes with #41
drill bits rather than #40. I think this is a good idea,
I’ll try it on the VS, rudder, elevator and trim tab.
Scotch Brite Wheel This is not a precision
instrument.If you want straight lines and an even appearance, use
files and sandpaper blocks and Scotch Brite hand pads. You
can’t get straight lines from the edge of a wheel. You
are better off with a disc/belt power sander. Some people mount
their wheel horizontally in a drill press. Much better idea, give
it a try.
Grinders/Grinding Stones Save these for
steel, they will clog up if you use them with Aluminum.
Files Rub Boelube wax into your files
before use—they cut better and clean up well.
Power Drill Buy the best drill you can
afford. This is one tool that you will use the most, and on
other projects besides airplanes. I bought a 3600 rpm Sioux
palm drill, and I’m glad I did. High RPM is better for
Aluminum, and the Sioux drill is light weight. It is
variable speed, but not reversible. It might be nice to
have reversing at some point, but you should also have a battery
powered reversible drill/screwdriver for miscellaneous stuff.
Bucking Bars
Cover unused surfaces on your bucking bars with duct tape to
help prevent them from scratching your parts.
Primer I chose Sherwin Automotive E2G 973 Vinyl Etch Wash Primer for the following reasons:
Note: information obtained from Sherwin-Williams.
Your primer choice may be different, but I based my decision on readily available information from the Sherwin Automotive website and technical support staff. I have found very little useful information available online from PPG, DuPont and others. link: http://www.sherwin-automotive.com/products/. Just to be fair the Sherwin-Williams consumer web site is one of the worst on the internet (not just for paint!). The automotive web site is a bit better.
I will admit that the E2G 973 does not provide a nice
finish like a pigmented primer.
Primer Touch-up
Lacquer thinner dissolves the E2G 973, but a quick wipe just
softens the surface. I do this prior to spraying touch-up
primer (Sherwin 988 aerosol) to ensure it sticks.
Cleaning/Degreasing Parts
According to Sherwin-Williams technical support, cleaning
parts with lacquer thinner leaves a film, but this is not a
problem when using their vinyl etch primers. To be safe, however,
afterwards I washed the aluminum parts in Dawn detergent solution
and wiped dry with a clean towel. Steel powder-coated parts
I did not, to prevent flash rusting. This appears to leave
the parts perfectly clean.
Elevator Trim
I ordered my empennage kit with the electric trim
option. At the last minute, I decided that I would sooner
have the manual trim, so I returned the electric trim kit to
Van's. My thinking is this: If I had an electric
failure, I would lose my electric flaps (not a serious problem),
but losing elevator trim can be very distracting and somewhat
dangerous. Be able to fly the airplane without electrics is
not something I ever want to do, but emergencies happen, and it's
best to be prepared.
Workshop You need workbenches at two
heights:36-38" for working on small parts, 32-33" for
working on assemblies. I built the EAA standard work
tables, then had to make ‘shoes’ for one of them to
increase the height. http://www.eaa1000.av.org/technicl/worktabl/worktabl.htm.
I can remove the shoes to drop the table down again. An
improvement on the EAA design would be to make the frame 2"
narrower and 2" shorter to allow the top to extend over the
frame. Then you use smaller clamps to attach things to the
table edges (such as spars when sanding edges etc.). Workshop
lighting is very important. I have about 20 lights in my
shop, including fluorescent, incandescent and task lights.
It’s still not enough. Double what you think you need.
My workshop is in my basement. I considered building a
garage (hangar) to build my airplane, but found some advise on
the internet which said ‘make it easy and convenient to
work’. Going into a heated basement to work for an
hour is far more convenient than a cold garage on a winter’s
night. I won’t be able to build the fuselage in the
basement, but most everything else should work out.
Buy a good compressor. I went for a 220V heavy duty
job. It cost about 50% more than a 110V compressor, but it
will run my drill, die grinder or paint sprayer without
complaint. A 110V compressor will have real trouble keeping
up with more demanding use. It will be adequate, but it
will have to run longer and more often, you will get more
condensation (water) in the lines, and painting topcoats may be a
challenge. On the other hand, the 220V compressor is less
portable due to the lack of 220V, 20A circuits in a typical
house. My solution: I bought 200' of air line from
Princess Auto on sale, so now I can reach almost anywhere. I
keep the compressor in a separate room (even a belt-drive oil
lubricated cast iron compressor can be noisy). I built a
20’ long length of copper line as an air cooler in series
with my air line. It runs along in my crawl space to cool
the air prior to my moisture trap. I’ve seen better
designs with a coil of copper line immersed in a bucket of water
for cooling.
The story of P-Mags and E-Mags
When I heard about EMagair, the maker of P-MAG and E-MAGs, I thought 'what a great idea!'. I designed out my conventional mags and designed in the EMagair products with their assistance.
I placed my order and waited, but the products were delayed several times and I finally had to get my engine built so I cancelled my E/P-Mag order and switched backed to conventional mags. I'll leave all of the wiring in place for a future upgrade, so if EMagair can ever deliver and proved their reliability, I can upgrade. It will cost me more money, but it's a safe way to go.
I have been involved in dozens of new product introductions in my career, and many of them had technical problems and delays at the beginning. The company I have worked for the last 17 years (PMC-Sierra) was very proud of it's record on getting new products out on time with minimal technical problems, but sometimes we had some problem cases.
My opinion is that EMagair is having technical problems, and they want to take the time to get their products right. That's what they should do. In my discussions with them, however, I became concerned about how they are going about things. It's entirely possible that they will have a great product, but a broken business plan. I hope they are getting good business advice.
My background is engineering, marketing and business analysis (mergers and acquisitions). I have seen a lot of companies fail, even though on paper they have a killer product. It's all about the right plan, the right people, execution and documentation.
Documentation?? Yup, 90% of the businesses I analyzed failed because of poor documentation. When you have 50 people designing a 20 million gate integrated circuit, you better get the engineering documents, manufacturing and customer documents right or you will never, ever find all of the bugs, never ship the product for revenue and never have a successful business.
EMagair is a different animal, I agree... but being successful with a product like this (eventually to be certified) will swamp them in paperwork. For example, what is their qualification test plan?
Are they going to let their customers debug their products for them? I hope not. If I were them, I'd get 3 or 4 aircraft test beds in the air as soon as possible with backup magnetos, and run them through a battery of tests, collect data and analyze it before I shipped any products to customers.
Things to think about...
- will they work at temperature extremes?
- will they work with a lot of temperature cycling?
- what about high altitudes?
- what about vibration (normal and abnormal)?
- what about contamination from engine fluids or dirt?
- what about reliability in corrosive atmospheres?
- what about susceptibility to electrical interference (comm radios, transponders, etc.)?
- what happens when the internal micro goes insane?
.... and so on.
There are many questions. They have been good at answering some, but not others. Food for thought. Good luck to them. If they are successful I will upgrade.