Building the Velocity XL-RG

Visit the guestbook!

January, 2009

It took until mid November before I finished the tractor engine rebuild. Then it was time to start building again. But now I'm at a crossroads.

It's time to build the strakes. It's kind of hard to describe the strakes so I'll use visual aids.

Here's the top view of the fuselage. At the rear is the center spar extending out the sides. The main wings will attach to this spar.

Here it is with the wings attached. Now for the fuel tanks. On aluminum wings, they're hollow and hold fuel. These wings are a solid foam core and can't be used to hold fuel. So an interface between the leading edge of the wing and the fuselage is created that will hold the fuel.

The shaded area are called "strakes" and will hold (hopefully) about 40+ gallons of fuel on each side. But here's the catch: To properly build the strakes, the wings need to be mounted. But I don't have a big enough shop. With both wings on, the shop is about 12 feet too short.

Here's a picture with one wing on.

I could build the strake one side at a time but that creates some problems.

1) It takes twice as long.

2) Even with one wing on, it's a pain moving around to do the work.

3) With one wing on, the center spar is unevenly torqued. It's possible, with supports, to relieve this stress. But it's a bit of work to get it just right.

So I fussed about whether to build a temporary extension so that I could fit both wings on, do it one side at a time or send it out to a facility where I could do both sides.

Because this will determine how true the plane flies, I decided that caution rather than blindly fumbling in was the best course of action.

I met Tom Wright at Oshkosh last year. Tom owns Advanced Composites Technologies. In addition to having build numerous Velocities, he's also builds UAV's. So we made arrangements to ship the plane to Friedens, PA.

 Getting the plane on the trailer

Loaded up with the wings underneath, strapped down and placarded.

Once at the shop in Friedens, PA the wings (both) were attached and the plane was raised up and leveled.

Left side

Right side

The strake skins are manufactured at the factory. They're made of 1/4" sheet of Divinycel foam with fiberglass cloth on the top and bottom. Where the strake skins attach to the center spar, the foam has to be removed and the foam is beveled and then covered with a layer of fiberglass.

Here's a strake skin with the foam and inside layer of glass removed.

The inside of the strakes had to be sanded, filled and recovered as they were not smooth enough.

Inside of one of the strakes after sanding.

This is the bottom left strake skin after sanding with a layer of BID and peelply. At the bottom of the picture you can see where the foam was removed.

Then it's time to determine how far forward the strakes will join to the fuselage. This is one of the factors that determine how much fuel you'll be able to hold. The farther forward, the more fuel. A limiting factor is the door latching mechanism. Some builders have modified the door latch they can put the strakes even farther forward. I decided to skip that modification. I am hoping for 44 gallons of fuel per side.

One of the critical factors is getting both side IDENTICALLY positioned.

Here are the markings on the pilot (left) side.

And on the co-pilot (right) side.

The center spar which is the structural component that the wings mount to will be the back wall of the fuel tank. It needs to be prepared.

Left side of the center spar being prepped.

Right side of the center spar finished and ready for the strake.

The left side lower strake skin mounted in position.

Right side lower strake skin.

Next comes fuel lines and baffles.

February, 2009

The bottom skin of the strakes are now permanently attached to the spar, fuselage and door.

The cutout for the landing gear has to be made. This allows the gear to raise into the strakes. Basically, the gear leg is raised until it hits the strake. Mark where it hits and trim away part of the strake. The gear will now raise a little further. Keep repeating until the tire hits. Then start cutting out larger pieces until the whole leg and wheel retract into the strake.

Looking under the right strake at the fuselage. Towards the left edge of the picture, you can see the opening on the side of the fuselage for the main gear leg. You can also (barely) see part of the bottom of the strake where an opening has been made for the gear leg.

Right side strake. Gear in the up position. The gear leg cover and wheel cover is positioned.

Two things to keep in mind here. One is that fixed gear Velocities can hold a bunch more fuel. And second, I am going to pick up a couple gallons per side with a neat trick. Notice how the wheel is at an angle when it's fully retracted? Rather than seal that whole area off, I'm going to put an angled "cap" on it and use that space. Should yield about 1.5 to 2 gallons.

Making sure there's sufficient space all around.

Left side wheel well and gear leg well epoxied in place. Looking from the top (rear).

Left side wheel well and gear leg well epoxied in place. Looking from the front.

Right side (from front). Landing gear is held up with a piece of wood.

Something else to point out here. Notice on the right side of the picture you can see a rectangular cutout in the side of the fuselage. This is an optional feature that almost every builder does. This is next to where the rear seat is located about elbow height. Basically the side of the fuselage will be moved out creating a space. This space can be used for open storage (no door), closed storage (door) or just a big ol' armrest area. As an open area or open storage it makes a big difference how big the cabin "feels".

How far you move this out depends on what you want. If you want a big area for storage, you move it out about 12". But you lose fuel capacity. Don't make the cutout and you pickup about 5 - 7 gallons. I decided to split the difference. Mine will be moved out about 5 1/2". I'll lose a little fuel but gain some space. I toyed with the idea of making it angle in at the top but decided that would just add work with not much gain in fuel capacity.

The location of the wheel and gear leg well get transferred to the top strake skin. Also the fuel cap is installed.

I'm doing two things different here. Number one: I'm not using the fuel cap from the factory. I looked at them but didn't like the design and construction. I found a company that makes the fuel caps for race cars and bought a couple of those.

Number two: Static discharge. On metal aircraft, before you fuel it, you attach a grounding wire to the airframe. The fuel nozzle is also grounded so that when it comes close to the opening, there's no chance of a spark. But this is non-metallic construction. Which means there's no way to ground the fuel tank opening. So I'm attaching a wire from the fuel tank opening and running it to a metal tab outside. That way when I fuel up, I'll attach the grounding wire to the tab and the fuel tank openings will be grounded.

Glassing in the wheel wells and gear leg wells. Holding the wells down with a heavy beam while everything sets up. Also starting to install some of the ribs. These vertical pieces are to strengthen the area and to prevent the fuel from sloshing around.

Closeup of the inside-rear area.

Right side from the front. After everything sets up.

Additional ribs installed. Notice in the corners where the ribs/baffles meet that there are small cutouts. This allows the fuel to move. The cutouts are called "mouse holes". :-)

Tops of the wheel wells being prepared.

Inside of the plane looking back at the right side. Fittings for the fuel supply, vent and return. On the left side of the picture you can see the storage area.

Right side, looking back from the front. Ribs/baffles in place.

Right side, looking back from the front. The trial, temporary fitting of the top skin.

March, 2009

Because there's no way to see inside the strakes with the upper skin on, the height of the ribs/baffles is an approximation. To get a perfect fit, duct tape (is there anything it won't do?) is applied to the inside of the upper skin where it will contact the ribs. A bead of epoxy/Cabosil is run on the tops of all the ribs. The upper skin is then lowered in to position and left overnight. The next morning, the upper skin is carefully removed.

This is the result

After a little clean up of the spots where oozed too much, it's time for Jeffco. As you may remember from the sump tank, Jeffco is tricky stuff! First off, it's not needed with the type of fuel that is presently used for piston engine airplanes (100 octane, Low Lead). But if the fuel is ever changed, it could react or eat through the epoxy. So just about all builders coat their tanks with Jeffco. A very hard, resistant epoxy. The problem is the stuff has a tendency to exotherm (heat up) rapidly. When it does, the mixture will set. So it has to be mixed in small batches and applied. Oh yeah, and you have to keep a wet edge. If the area that you're working next to sets up, you have to let it harden and then sand it.

Shiny fuel tanks!

The last picture shows the wheel well. Remember how I said that I was going to use the the angled area for additional fuel? That area needs a bit more work. Openings so the fuel can flow in and out have to be cut and then the Jeffco can be applied.

Wheel well jeffco'd:

Here's the outside edge of the left strake looking back from the front. On the right, you can see two of the bolts that hold the wing in place. The hole in the bottom provides access to the bolts so the wing can be removed.

Inside of the plane looking at the right side. The rectangular opening is the area that extends into the strake. The plans say make it 11 inches deep but mine is only about 5 inches.

Another modification. As you have seen, when the landing gear is retracted, the wheel is at an angle. To allow it to retract further, a "divot" is cut into the inside of the top skin of the strake. Then it is covered with two layers of BID.

It's kind of hard to see it in this picture, but the lighter colored area is the divot.

Top skins with a coat of Jeffco. You can see the area of the wheel well that won't be holding any fuel and the divot is a little easier to see.

The inside of the top skin has to be sanded where it will adhere to the bottom strake and ribs.

Here's the inside of the top skin after sanding.

Finally it's time to bond the top strake skin on. An epoxy/cabosil mix is applied to the top of the outside edge and ribs.

Strakes ready for the top.

Once the top is on, everything is weighted down to hold it in place.

After everything has cured, it's time to test for leaks. Since how well the fuel caps seal is an unknown, they're covered with plastic and taped. Then tubes are attached to the fuel lines. An altimeter is connected to one and a vacuum pump to the other. The pump is turned on until the altimeter reads 1,000 feet. Then everything is left overnight. If there are no leaks, the next morning the altimeter will still read 1,000 feet. If it reads zero, then there's a leak.

Fuel tank test underway.

Everything is done and now the airplane comes home!

Backing down the driveway.

It's hard to see in the previous picture, but the winglet of the right wing was rubbing against the center spar. Unfortunately, the result was some damage to the winglet.

Damaged winglet.

This is not a difficult fix, but I am rather disappointed that the shipper didn't check the location of the wings while in transit.

Now for the before/after shot.

Here's a picture from the webcam on 12/30

Here's a picture from the webcam on  3/29

April, 2009

If you look at the previous picture, you can see the canard just to my right. (bottom left corner of the picture. You'll notice it's kind of... splotchy looking. That because I put a guide coat of primer on and lightly sanded it. What I discovered is that the surface of the canard is not very flat. Lots of high and low spots. So I started filling the low spots and sanding it down. Then another guide coat of primer, sand and discover more low spots. After a couple weeks of this, both top and bottom were perfectly smooth.

Then it was time to prime the canard. I used a Akzo-Nobel Epoxy Primer and the first coat was put down really thick. Once that's on, I was able to see all the little pinholes and scratches. I filled those and then put down another coat of primer.

Here's the result.

Then I wanted to get the ballast for the landing lights installed. Each light has a small ballast that will have to be mounted on the covered portion of the canard. So I cut a few small wood pieces and drilled holes and recessed the nutplates.

Mounting blocks for one ballast.

Mounting blocks with nutplates glued in place.

I put a small piece of tape over the holes for the screws then used epoxy to mount them to the canard. Once the epoxy cured, I covered the mounting blocks with 2 layers of BID.

Mounting blocks with once the layup has cured and the screw holes were cleaned up. I've got the cables in place and covered the plastic to prevent them from getting any epoxy on them.

Ballast in place

I did a test of the landing light to make sure that everything was working and also to check that they didn't generate too much heat.

Landing light installed.

Landing light lens installed.

Lights on!

These things are really BRIGHT! But they are also generating too much heat. The plexiglass lenses are getting soft and starting to warp. After some conversations with the engineers at XeVision, they said that using the lights in perfectly still air for extended periods would generate excessive heat and that in the "real" world any air moving over the canard would keep things cool enough.

So I ran the test again. This time with a small fan about 3 feet away blowing on the landing light a it's lowest setting. The result was that highest temperature on the lens was only 180 degrees. The highest temps on the canard was only 110 degrees. Since I'll only be using these when the plane is moving, there shouldn't be any problems. But just to be sure, I'm going to install a vent that will generate some additional airflow inside the cavity.

First I drilled a hole from the back of the landing light cavity to the back of the canard. Then I put some epoxy in it and forced some nyla-flo tubing in.

Here's the back of the canard before I cut off the excess tubing.

Here it is after trimming

And this is what it looks like from the front before trimming

Back to the fuselage. Now that the strakes are done, I can finish up the main landing gear. The gear legs are held down by means of a locking bar called the overcenter linkage.

Looking at the back of the fuselage from the inside. The gear is in the "up" (or retracted) position.

Down and locked.

There are incredible forces acting on the gear legs front-rear. The position is maintained by a "socket" that prevents any movement front to rear. These sockets are basically molds of the gear leg. So I removed the gear legs and covered the tops with duct tape.

Gear legs covered with duct tape

Then, three layers of Triax are placed over the gear legs.

A lesson in building an airplane (May 2009).

One of my jobs when I'm not training (the thing that pays for the airplane) is writing training manuals. So I'm a bit more critical of instructional material than your average person and I'm constantly finding areas of this manual that need improvement.

After talking with other builders, this seems to apply to a lot of homebuilt aircraft, not just Velocities.

On to the task at hand... From the sequenced flow chart, I need to install the "Pitch Trim Actuator". Up and down movement of the airplane in flight is done with the elevators.  Pull the stick back and the nose goes up. Push the stick forward and the nose goes down. In cruise flight, you don't want to have to be pushing forward or pulling back just to stay level. So a small electric motor moves a spring to a position that will apply the necessary force so that you don't have to push or pull the stick to maintain a particular attitude.

This task has to do with mounting this electric motor.

Here's a page from the manual:

This is looking from the left side. The canard is on the bottom. The large black object is the actuator. On the left is where it mounts to the canard by means of the "Long Bracket" (Part Number VAB-02). The bracket will be connected to the "Aluminum Hardpoint" which will sit on the "Shim". Seems pretty straightforward.

Here's the text:

Hmmm. The first sentence is in bold. Must be important, huh? "Located a position for the trim spring that will not interfere with the radios."?!?!?!

What radios? Installation of the radios is a LONG way away. Heck, I don't even HAVE the radios. Nor have I even decided what radios or where they'll be installed. So how do I figure out where to put this thing? I looked at the websites from other builders and looked at their pictures. Hopefully, my location will be fine.

This is the area of the canard where I'll mount the actuator.

The piece of blue foam cut and formed to the correct shape.

A piece of aluminum cut to size on top.

Everything covered with two layers of BID.

The actuator.

The "Long Bracket".

Wait a minute... The actuator looks like the picture of the actuator, but the bracket doesn't look like the bracket. Back to the manual where we see the text "Modify the long bracket (VAB-01) as shown in Figure 10-2 to allow the actuator to move up and down."

Well this is getting interesting. I've got to cut this piece "as shown" in the picture. No dimensions, no template, just make it look like a picture in a Hanna/Barbera cartoon. Okay, that shouldn't be too difficult, just cut it so the end of the motor will fit.

But wait a minute... In figure 10-2 the "Long Bracket" is part number "VAB-02" but in the text they say "Modify the long bracket (VAB-01)"!

Now what?

So I reread the entire section repeatedly trying to determine exactly what I'm supposed to be cutting. In the end, I come to the conclusion that the text is wrong and the figure is right.

Long Bracket (VAB-02) after modification.

Hardpoint drilled, tapped with Long Bracket (VAB-02) and trim actuator mounted.

If I had to do this task again, I could probably do it in an hour. But with the research on the location, the part number discrepancy and trial and fit for the modification of the bracket, I probably spent the better part of 6 hours on this.

At this rate, I'll be done in ten years. :-(

June 2009

Rusty bearings
In preparation for mounting the brake assembly to the wheels, I had
to remove the wheels from their axles. When I did, I received a very
unpleasant surprise. It would seem that when the wheels were mounted
on the axle at the factory, the bearings weren't packed with grease.
The result was this:


and this:


Only one of the races was rusted so that and all four bearings had to be replaced.

Brake upgrade
This is a whole page in itself. Go here for the gory details.

Winglet repair
You may recall that when the airplane was brought back from PA, the
right winglet sustained some shipping damage.




To fix it, I had to grind the surface filler down to the fiberglass
and trim back the fiberglass. Then I had to cut out the foam.


Next, create a "plug" and bond it in place with epoxy/micro.


Then cover the entire area with two layers of UNI and the first coat of filler.


Sump tank fitting
When I went to mount the sump tank, I had another surprise. This one
was somewhat self inflicted. When I create the mounting tabs on the
sump tank, I made them flush with the back of the tank. The problem
is that the surface where the tank mounts is not flat. Part of the
transverse bulkhead layup extends out to where the tabs are. In this
picture one edge of the sump tank is just to the right of the center
of the picture. I could have left the original tabs on, but then
the tank would be sticking out about a quarter inch from the
firewall.


So I decided to make some offset tabs. So I got my handy sheet of
"Layup glass" (epoxy won't stick to it) and made so risers for the
mounting pads.



Then I put the glass and epoxy down and let it cure.



Finished sump tank with offset mounting tabs



To mount it you're supposed to drill through the firewall and use a
four bolts and nuts. But then you need two people to loosen or
tighten the bolts. So I used a Hangar 18 trick. After I drilled the
holes, I enlarged them on the firewall side so the head of the bolt
would be lower than the surface. Then I put the bolts in and covered
the heads with epoxy/micro.
Firewall side showing two countersunk bolts with epoxy.


Inside left view with the two bolts.


Sump tank installed and bolted in position.


Rudder conduit
The rudders (one of each winglet) are activated by cables that go
from the rudder pedals to the back of the fuselage to a bellcrank
and then out the wings to the winglets on the end of the wings. On
my Cessna those cables get from the pedals to the rudder by means of
numerous pulleys. On the velocity, the cables go through a nylon
tube (Nyla-flow) down each side of the fuselage. The tubing is
glassed in place. But at the rear, it has to hang in the air for
about 6 inches. During operation, this unsupported tubing can flex
and make for slop in the feel of the rudders. Another Hangar 18
solution. Where the tubing is unsupported, use a short length of
aluminum tubing.

Here's the tubing on the left side. I haven't pulled the nylaflo yet
but it will go inside the aluminum tubing.

Right side


And here's the finished product. nylaflo tubing installed and
covered with a layer of BID.


Closeup of the aluminum tube where the nylaflo goes in.



Whale tail
This is going to require some explanation. The center keel runs down the center of the fuselage on the floor. It's about 18 inches high at the front and drops to about 6 inches tall where it stops around 6 inches forward of the gear bulkhead. At the rear, it extends left and right to the sides of the fuselage. Inside of the keel is the aileron torque tube. Moving the stick left and right rotate this tube which causes the airplane to bank left and right. The only way to install the keel in a fastbuild kit is to cut it about 75% of the way back. Here's a picture from February 2008 where Rick was preparing to make the cut. You can barely see the red "cut" line.

 

Front part of the keel after the cut.

This part of the keel got installed when I was down in Florida. The smaller rear part is called the "Whale Tail" (you'll see why later). So now I need to install this part of the keel. When I fitted it in position, it didn't line up with the front part. Two possible reasons; 1) the mold used to make the keel has... warped and doesn't conform with the floor of the fuselage anymore. Or 2), The mold to make the floor of the fuselage has warped with the same result. Or it could be a combination of the two. In order to get everything aligned, I had to remove some of the material along the bottom rear of the whale tail. The farther back, the more material I had to remove. As I moved forward, less had to be removed.

Here's the whale tail in position (see why it's called a whale tail?). In the bottom left corner of the picture you can just see the seam with the forward part of the keel. Where the keel meets the floor is a flange that lays on the floor. But in the back you can see where I had to remove the flange so it would sit correctly.


The seam where the rear keel section attaches to the front.


Where there's a flange that contacts the floor, structural adhesive is used to bond the keel to the floor. Where I removed the flange, BID layups will be used to strength.

Here's the left side of the whale tail where it contacts the wiring duct. You can see a bit of the gray structural adhesive used.


Next I created a fillet of epoxy/micro and then covered the flangeless areas with 2 layers of BID front and back. Here's the same location with the BID layups applied.


Chicken strips
On the rear portion of the keel where I didn't have to remove the flange and the entire front portion of the keel it's attached to the floor with only structural adhesive.

Here's the right side of the keel about half-way back.


Close-up of the same area.


Normally, in this type of joint you would reinforce it with two layers of BID. The manual doesn't call for this, but I'm going to do it anyway. So I beveled the edge a bit, mixed up some epoxy/micro and then layed down two layers of BID. This will make it much stronger.


NACA filling
I installed the engine cooling NACA ducts when I was in Florida. They're held in place with structural adhesive but there's some finishing that needs to be done. Here's how they looked when I installed them.


What I did was to cover the seams with 1 layer of BID and then start applying filler.


Ceiling mount canard
I'm pretty much done with the canard for a while. But it takes up a lot of room and I lose access to a work area. So I got a couple pulleys and some screw-eyes and the result is the canard is now hanging from the ceiling.


Brake mounting
This is a fairly big job. Once I got the brakes upgraded, I need to get the wheels and brakes mounted to the gear legs. The first challenge is that the gear leg needs to be cut.
Here's the bottom of the gear leg and the four holes that are used to bolt the axle and brake torque plate to the gear leg.


This is the gear leg side of the axle mounting flange. Notice where the caliper is? Well not only does the gear leg have to be cut, it's going to be cut REALLY close to those bottom holes. So the first thing that I need to figure out EXACTLY where to make that cut. I don't want it any shorter than possible. To determine the cut location, I made a template from some masonite. It was basically trial and error but eventually I ended up with this.


Because black ink won't show up on the gear leg, I applied some masking tape.


Then position the template with the four bolts.


And trace.


The next challenge was to make the cut. The material used in the gear leg is TOUGH. I would probably ruin two $25 bandsaw blades cutting the two gear legs. Malcolm at Hangar 18 suggested using Permagrit blades in a saber saw. About $3 for a blade and it went through the gear leg like butter.


The heat generated by the brakes could cause the gear leg to weaken over time. To prevent this a heat shield is used. The factory ships a "phelolic" sheet with the kit that is placed between the gear leg and the axle/brake/wheel assembly. I elected to upgrade to a material called "Garolite". This has much better heat shielding properties. To cut the material, I used my template again. First I clamped to the Garolite to the template and marked it.


Then I cut the Garolite with the bandsaw.


To allow movement of the brake caliper through it's entire range, I had to create a notch for the upper torque plate mounting bolt.


Once I mounted everything, I had to disassemble everything and grind off material from the gear leg here and there until all the parts had necessary clearance. I probably mounted and removed the brakes over a dozen times.

Here's the end result.

 

July 2009

Preparing for "The Big Flip"
At some point, the airplane needs to be flipped over. It's not absolutely mandatory, but it makes putting the main gear doors on a thousand time easier. To flip the plane, I'll use a pair a of half-circle pieces of plywood attached to the center spar. Here's the two flip jigs.

Finishing... Again

I spent a bunch of time filling and sanding, filling and sanding, filling and sanding. When I was in high school, I worked in a body shop after school. I never developed the feel for determining high and low spots in a body. As a result, I used a guide coat. Basically, you spray a thin layer of primer and then sand it. Where the primer remains is a low spot that needs more filler. Here's one of the strakes after a few sessions filling and sanding.

Every now and then I have to use a pencil to remind me where to put the filler.

Just to feel like I'm getting somewhere, I decided to install the control stick.

Wing to Strake joint

Wing to strake interface (Remediation)

Where the wing root meets the strake has to be finished. Here I discovered that there was a bunch of work required. In order to accomplish this task, I had to rotate the fuselage so I could fit a wing on. For the most part the fuselage has been sitting like this:

But now it looks like this:

And here's me and my son Steve bolting the wing on:

Once I got the wing on I discovered a bunch of work that needed to be done. Here the front view of where the strake (right) meets the wing (left). Kind of a large gap. It should be about .030".

Almost a 1/2" inch gap here.

And here you can see the strake ends about 1/2" forward of the wing.

Now to fix this was going to require me to take the wing off and put it back on numerous times. And much of the time building I'm alone so first I needed to make this easy to accomplish. So I build a couply moveable stands. Here's the one for the wing root end.

By raising the cradle portion, I can insert some dowels and shims to obtain infinite positioning.

For the wingtip end I went low-tech. A sawhorse that sits on my wheel dollies. A true multi-tasker. Alton Brown would be proud!

At first I toyed with the idea of simply filling the void. But that resulted in a rather wavy seam. So I determined where the seam should be and drew a line. Here's the rear of the joint.

Then I put a placed a straight-edge along the leading edge of the strake and marked where it SHOULD meet the wing and marked that.

Now how to connect the mark at the front to the mark at the rear??? LASER!

With the laser positioned to create a beam from the front mark to the rear mark, I had to perfectly straight line. You can see here that my attempt to create the line wasn't exactly straight.

So I erased my first marks and created a line where laser indicated.

I have a really tough time sawing a straight line using a pencil (or pen) line. My buddy Malcolm gave me a great tip. Lay down some contrasting masking tape on the line. It's easier to follow that way.

I made the cut and removed the wing.

Then put the wing back on (see what I mean about the on-off thing?),  applied some duct tape (is there anything that duct tape can't do?) along the inside of the seam and filled it. Here's the result.

Then I applied a one BID layup on the inside for strength. After that, it was fill and sand, fill and sand, fill and sand to get the surface of the wing level with the surface of the strake.

Now that the wing is on, have no reason not to finish the repair to the damaged winglet. Here's the winglet with another layer of filler.

And here it is all finished.

Door handle

One of the things about the stock Velocity kit that I really don't like is the door handle. Some people call them "Toilet flush" handles. Here's why:

That's how you open the door from the outside.

The inside isn't much better.

Closed

Open

After poking around on the internet, I found some door handles designed for experimental aircraft.

Not only is it flush mounted, but it includes a lock. The handle is spring loaded and pops out to operate.

Installing this is going to be easy compared to making it work with the four pins. The person that designed the handle made it for a Van's RV airplane. They only have two pins (one going forward and the other going towards the rear). In this inside view you can see the center pivot screw and the forward and rear screws that the two links connect to.

With the interior handle removed, you can see the hub (or what the manufacture call the "driver plate".

So how do you connect four links to a handle designed for two? Improvise!

The Velocity door has an upper front and rear pin like the RV's. Which means I only needed to accommodate the two lower pins. So I made a "Cam Plate" that would tie in to the existing hub. In this picture, I haven't drilled the two holes for the lower pins yet.

Here it is on the hub.

Once I was certain that I could design the interface between the handle and the pins, I was ready to install it in the door. First, I decided that I would use the hole for the existing handle for the lock of the new handle. Then I drew a level line on the outside of the door centered on that hole. I drilled a pair of holes on that line so I would know where the centerline was on the inside. Then I marked where the handle assembly would be and where the hub would be.

Using Malcolm's trick, I further identified the line with masking tape.

Then I cut the inner skin and removed the foam leaving only the outer skin.

Next I cut a template so I would know where the cut the outer skin.

And marked the outer skin.

And cut the opening.

I had to recess the inner skin and foam to allow for the movement of the handle and lock.

Handle in place (closed).

Handle in place (open)

From the outside

Besides the appearance, another bad thing about the handle is that it's HARD to operate. Once I looked at it I discovered why.

There are four pins that engage the doorframe to keep the door closed. These pins are attached to shafts that tie in to a cam that the door handle operates. The reason it's so hard to operate is that when the cam rotates, the shafts move laterally and bind in the sleeves at the door edge. Except for the upper/forward pin. That one uses an intermediate link.

In a previous life, I was a repaired IBM Selectric Typewriters. They're the typewriters with the golf-ball thing that bangs into the paper to make print. Something like over a thousand moving parts with almost 500 adjustments. It's a wet dream for Rube Goldberg. So with that background, I was certain that I could build a better mechanism. The key was to keep the pins (and their attaches shaft) movement linear. That would require what I would call an intermediate linkage. So I make the shafts shorter, mounted a sleeve to maintain the alignment and built eight intermediate links.

Here's the end result.

Closed:

Open:

I located the holes in the cam so that the links would be over-center in the open and closed position. This is to keep the handle from opening (or closing) by itself. I also put a spring on one of the shafts to "load" the mechanism. This will apply pressure keeping the handle in the open or closed position.

Here's a video (1 MB)

Then I had to remove the receiver sleeves in the door frame because they were set for the positioning of the old pins. Once I got them removed, I put the doors in just to give myself a pat on the back.

Right door.

Left door.

Uh-oh. Something doesn't look right on the right door. So let's play "Find Waldo" and see if you can tell what's not... good.

I'll wait.

Did you find it?

Here's a close up.

It's not level! I put these marks on the outside but all the cutting is done on the inside. Somehow, I put the door handle in and didn't check the outside alignment. I thought about for about 5 minutes before deciding to remove the handle to correct it. I know it's only off by about 1/8". But there's the slippery slope. If you let this slide, it makes it easier to let the next thing go and pretty soon you're flying something that's held together with duct tape and bailing wire. Besides, what if I put a stripe down the side of the fuselage and it's right next to the handle? Then it's really stick out!

Removing the handle, enlarging the opening and epoxying the handle back in only took about two hours so it wasn't a huge issue.

Tie-Down Ring

The last item is the main wing tie downs. When you park your plane for any length of time, you need to tie it down. The factory supplies a pair of screw eyes that you bolt to the bottom of the ends of the center spar. But that just looks bad. Two big honkin' rings hanging off the bottom of the wing. So builders have gone with a pivoting ring that's spring loaded so that it's recessed. This is the same type that's used on my Cessna. I, however, went with plan "C". A retractable ring that uses gravity instead of a spring. Springs fail, gravity doesn't.

Here's the tie-down ring when not in use.

When the wing is on, only the little tip will be sticking out. Snap it with your finger and pull it down and the ring is exposed.

With no rope through the hole, gravity pulls it back to the recessed position.

August 2009

Fuel Cap (remediation)

I wasn't present when the fuel caps were installed. When a saw how they were installed, I wasn't nuts about them but I wasn't certain that they were not... optimal and didn't want to make a stink about it. Besides, I figured it would be a real pain to fix anyway. But after looking at planes at Sun-n-Fun and Oshkosh, I knew something had to be done.

Here's what the fuel caps look like.

I wanted a flush installation. I think part of the problem was that these fuel caps aren't the ones that come from the factory. Those were kind of cheap looking with a fair amount of plastic. So I found a company that makes fuel cell caps for race cars. No plastic, all metal, very high quality.

The first order of business was to cut out the cap. I first cut out just the cap itself. But then I realized that I would need to put a backing plate inside. So I cut the hole into an oval.

Here's the hole with the backing plate.

Then I cut a hole into the backing plate and put on a couple coats of Jeffco (fuel resistant epoxy). Once it was dry I mixed up some more Jeffco and added some Cab-o-sil (thickener) and spread it around the edges. Then I put the backing plate inside the fuel tank and pulled it up against the inside of the tank.

Now I had to make a mounting flange. So I clamped the fuel cap collar to a piece of 1/4" aluminum stock.

Drilled (and tapped) the holes for the collar.

Then I marked the center for the BAH (Big Assed Hole).

Then I used a hole saw to drill the BAH.

Finally I cut out the outside. My 15 year old jig saw really wasn't up to the task. But the outside cut wasn't critical.

Then using Jeffco with cab-o-sil to thicken it, I secured the flange in place.

The next step was to cover the screw holes with some duct tape. (Here I've done all but one) Then fill in any voids with thick Jeffco and cover the whole thing with fiberglass.

Then I cut out the holes, plopped some some thick Jeffco down the screwed down the collar to the mounting flange. Once it cured, I filled and sanded the surrounding area:

Much better.

Interior Lights

Soon, I'll be installing the overhead fresh air plenum. I'll need the have the lights fitted before I get to that point. I looked at Oshkosh for some good LED map/courtesy/flood lights. I found a bunch but as is the case with many things aviation, just because it goes in an airplane, you can usually add a zero to the price. What should cost $12 ends up costing $120.

$110 lights

$130 lights

$145 lights

See what I mean? But just like the door linkage...  Something I know about.

Here's what I did. I found a light for boats. A Perko 12v light.

I bought 4 of these at a marine supply store. Now this fixture has a 12volt incandescent light inside (I'm going to have a 28v electrical system). But that didn't matter because I just wanted it for the plastic.

I removed the bulb, mounting hardware and wires.

I purchased a dozen high intensity white and red LEDs at (of all places) superbrightleds.com.

Now I was venturing into uncharted territory. To have circuit boards manufactured would have cost me about $100. I discovered a way to make them myself. I created the layout using a free PCB (Printed Circuit Board) design program I found on the internet (Ahh, the internet. Is there anything it can't do?).

Now here's a neat trick: If you print the layout on slick, shiny paper, it transfers to the circuit board better. Finally a use for all those clothing catalogs my wife gets in the mail.

I picked up a blank copper clad circuit board and Radio Shack.

Then I put the paper on the circuit board and using a regular clothes iron, transferred the ink to the card. The paper comes off by soaking the whole thing in water for a couple minutes and then it goes into an etching solution (purchased at Radio Shack) for 20 minutes.

I cut out the individual, circular PCB and epoxied it to the back of the light fixture. Then I drilled the holes for the LEDs, resistors and leads and started soldering.

This first one was a "proof of concept" prototype. I just wanted to make sure the design worked. So I pretty much slapped it together and installed some test points instead of wires.

I SAID it was a prototype. It's not SUPPOSED to look pretty.

Red

White

WooHoo!

One thing I didn't like was when I soldered the components in the solder would run all the was along the trace. On real PCBs there's a "solder mask" that contains the solder. Then I discovered that you can create a poor-mans solder mask using glass paint from the hobby store. This is paint that you can use on glass to create a stained glass effect. After painting it on, you bake it in the oven to cure it. After that, you got a solder mask.

Here's a "production" model.

Total cost for the for lights: About $50.

Strake Extension Cutout

One of the things Ann did at Oshkosh was look at every single Velocity interior she could find. Since she is designing the interior, she needed ideas. Unfortunately, she found some.

Here the scoop. The strake extends forward about halfway into the door. What most people do is make a triangular cutout in the door and use that space as a type of arm rest. My plan was to skip this step. Ann didn't like that. She and Malcolm strongly "suggested" that the cutout be made... and it was.

But there's a catch. When I designed the door linkage, I didn't think there would be a cutout. If I did, I would have accommodated it. As it was, it required a bit of a workaround.

First I had to remove the lower/rear pin and it's linkage.

Then it had to be relocated forward.

Next I cut out the door panel where the strake extension was. That's when I noticed that I would need a slight dogleg in that link.

The strake is made of 1/2" foam with a outer and inner fiberglass skin. That "sandwich" of foam and fiberglass is what gives the structure it's strength. Now here's a Hangar 18 special: Remove the inner fiberglass skin and foam. That way you pickup an additional inch of room. But it's weak. Carbon Fiber to the rescue. I hadn't worked with CF before but afterwards, I think it's easier to work with. If only it weren't so EXPENSIVE. Here's two layers of carbon fiber ready to be cut and laid in place.

Opening before:

Opening after:

And it's stronger.

October 2009

El Grande Inversa (The Big Flip)

There's quite a bit of work to perform on the bottom of the fuselage. Mostly finish type work but some mechanical work too. Trying to do this work from underneath is difficult so while the fuselage is still fairly light it's easier to flip the plane and do it from the top. So I built a set of semi-circular flip jigs and bolted them to the center strake. Then I put out a call for a number of people to help with the manual labor. Here's Mark (left) and John (right) wondering "how in the hell is this thing going to fly?" before the flip.

I put a sawhorse on top of (it will soon be underneath of) the canard bulkhead to support the front once it's flipped.

Ken walking around wondering "how in the hell is this thing going to fly?"

Me, Mark, John, Ken, Steve and Tom staring the lift.

Me (left), Steve (right), Mark (behind Steve) almost at the halfway point. John (far left) is looking like he wants to get as far from this operation as possible.

Over the top. Everybody else has moved over the other side. I'm just leaning on this side so everybody else can feel a little extra weight.

Coming down.

Just a little further. In addition to supporting the front, the sawhorse also makes for something to hold onto as John figured out.

The eagle has landed! Tom (left, and note the t-shirt on a 40 degree day), Ken (middle) and a happy me (right).

Rolling the turtle back in the shop. John (left), Mark (middle) and Steve (right, and note the shorts on a 40 degree day) pushing.

Official event photographer Sarah.

Nose Oil Cooler (Cabin Heat) Outlet

Now that the fuselage is upside down, the first thing I started on was the nose oil cooler outlet. Without getting into all the aerodynamics, suffice it to say that the shape around the outlet is important. Here's the side view before. 

Bad boys, bad boys, whatcha gonna do?

Yes, it's a COPS reference (get it? Change Of Plan?).

When your done trimming and mounting the door, it looks like this at the top when the gear is up.



That big honkin' gap is there because when the gear comes down, the door would hit the fuselage and prevent the gear from fully extending if it was any longer. I guess the theory is no one will notice it's there when the gear is down and the only time the gear will be up is where it's in flight. But I'd know it's there.

A couple emails to Malcolm revealed that I COULD have saved the extra to use a small door to cover the opening. But I couldn't do that because I used the "sneak up on it" approach when I located the final position of the cut.

So I covered the side of the fuselage next to the gear door and laid out a few layers of triax and BID (so it would match the curvature of the fuselage). Then I cut it to fill the opening. To accomplish this, I used the tape-it-to-the-outside-and-shine-a-light-from-the-inside to locate where to cut.


 

Then I cut and drilled a pair of hinges and did a dry fit.


Yep, it moves.


I riveted the hinge to the mini-door and put nutplates on the side that would mount to the fuselage.

Next I beveled the edge and built a flange so it would fit with the door.



Here's how looks all installed and operational.



Painting the main gear legs

 

The main gear legs don't have to be painted. Neither do the gear wells. But it would look so much nicer if it's not bare fiberglass. The gear legs are going to be hit by small rocks kicked up be the tires during takeoff and landing. So regular paint would look pretty bad after just a couple takeoffs and landings. Malcolm suggested Zolatone paint. It's "splatter" type of finish that takes abuse without showing and doesn't require prefect finishing prior to painting.

So I ordered a quart and started shooting. This stuff is a pain to shoot! If my gun had a larger nozzle, it would probably be easier. As it was, every now and then the nozzle would get hopelessly clogged and I would have to clean it out. What could have taken 15 minutes with the correct nozzle took about 90 minutes.

Gear well:


Closeup


Gear leg

Finished and reassembled.