What about a motor?

I visited the two local (hour and forty-five minute) grass strips to the West that almost certainly will not allow a car to drive on the runway.  So, what's plan B?

I found two local paved runways (about an hour and a half away) to the East that are in Class G airspace and look to be very low traffic.  Assuming I can't get a car on those either, what's about some power, cap'n?

Came across the E-Help Student system on YouTube, built for ground launches of a hang glider.  With the similar wing loading of the Goat to an old hang-glider, this seems like it'll be just about right to be a sustainer.

Cue some pictures...

Mounting the Rotomax 150cc motor to a 2in tube took some sheet metal brackets.  Not much sheet metal work on a typical Goat, so went out to buy a small sheet metal bender from Harbor Freight to bend these two.

The wiring harness was not the most glamorous task, and I'm still going back to look at the XT90 connectors once I take some measurements of the current during ground runs.

First test runs were literally on the bench in pusher mode.  The ESC needs some settings tweaks for softer start, and the brake needs to be on, but she does spin.

Next is figuring exactly how to mount the motor.  The two main options are behind the seat, like most powered Goats, or on a post ahead of the seat forward of the wing leading edge.  That'll be tomorrow's game before the big game and snow.

Other to-do's:

• Gap seals for the control surfaces
• Trailer tags (paperwork in the mail for the fourth time)
• Carrier cradles for on the trailer (started)
• Line and release system for auto-launch
  

Quick assembly and disassembly

I did a quick assembly with an old friend in order to adjust the aileron cables.  The aileron surfaces are now level with each other and move freely as they should, with the stick centered at neutral.

The one point I wanted to note is that the strips of Velcro around the wing to hold the aileron and flaps up made a WORLD of difference during assembly.  It was much easier to maneuver the wings during setup.  I am slightly disappointed that I didn't modify the ailerons to let them fold flatter (it was my change that caused the interference), but it'll be okay.

Also, the right order of operations is to connect the wing panels while flat on the ground, then stand them up using the cabanes and struts.  Last time I tried to stand them up and then connect left/right panels, and it was awful.

Next on the list is a tip dolly.  I already have the wheels, so just need to create the little dolly itself.  Should be a fun small project.

This Prius meant for towing

It only took a few minutes to realize that putting the wing on top of the Prius looks like a bad idea.  I mean it could work, but boy it looks awkward.

Setting the wing down behind the car, it looks MUCH better.

A trailer bed needs to be 4ft wide and 18.5ft long at minimum.  This picture shows 2ft between the car and wing, but 3ft looks a bit better for making turns.  If I can keep the overall box height to below 4ft from the ground, air should flow cleanly from the back of the car.

Musings about transportation

There are not a whole lot of physical things left to do on the aircraft, so I'm looking at transportation as the next big task.

A trailer is the obvious choice.  I already have a 4x4 trailer base that could be stretched and a new top made to haul Goat, and I could enclose it to store the aircraft in the trailer outdoors.  The major downside is that I don't have a good place to store the trailer when not at the airfield.  It can't stay on my street for more than 10 days.  I could push it into my back yard, but don't want to be "that" neighbor.  The trailer is even too long to store inside my garage.  And the vehicle I have to tow is a Prius, which I have seen towing a Sunfish sailboat on a trailer, but towing isn't approved.

Here is a flatbed trailer that I was looking at pretty hard:

Here is the Yando Goat trailer, which would be similar to my plan for a home-built enclosed trailer:

The other option is a rooftop system.  A Prius is also not the ideal rooftop vehicle.  The Thule roof rack only spaces about 27 inches between bars, and the Yakima roof rack spaces 34 inches.  For a wing panel that is 18 feet long, there should be more support.  And I have to drive about 60 miles at highway speeds to either of the two places targeted for a maiden flight, so it needs to be well secured.

This guy had a narrow roof rack for the long Goat wing, so maybe it would work for me.  It just looks sketchy for highway use.

This guy has a forward support mounted somehow under his hood, but which gives a lot more support to the length of the wing panel.

The Prius does have a pair of screw-in eyebolt locations in the front bumper, typically used for towing.  These might be okay bolt-points for mounting a support frame.  But how about something on the rear bumper?  Apparently you can get these kayak/canoe bed extenders that plug into a hitch:

The combination of a roof rack and support T-frame would let me strap the wings to the roof rack, and slide them reasonably far aft to leverage the support coming off the hitch.  Would it look weird?  Probably.  But that just might be the best option I have!

Some to-do items checked off

From lessons on the first fully-covered assembly, here is my to-do list:

• DONE flip aft cabane bolts to avoid hitting the aft pins.
• DONE aileron pushrods are hitting bad. Need to free up.
• DONE permanantly mount the aileron pushrods?
• DONE install missing cotter pins:
• DONE left aileron x3
• DONE left flap x2
• DONE right flap x2
• DONE right aileron x3
• DONE rudder pedals x4
• DONE control stick x1
• DONE forward sweep cable attachment to nose x1
• DONE left cabane x2
• DONE right cabane x2
• DONE velcro straps to keep the control surfaces up on the wing before assembly. 
• DONE add bungee to hold the struts against the cabane?
• DONE replace the forward nose tube (it is twisted)
• DONE weigh (Mar 2021)
  
• DONE adjust aileron line tension and re-center by moving the knots (Mar 2021)
• DONE gap seals... ailerons, flaps, rudder, and elevator. (Sept 2021)
• Trim color paint.
• Wing root kiss seal.
• Wing tip dolly.
• Wing wheel.
• Strut fairings.
• Jury strut fairings.

Here's what I did with the aileron pushrods ... crimped over the thin aluminum support plate embedded in the covering, and also switched to a bolted pin (per the drawings) that is lower profile.  Turns out the other end of the pushrod can be clipped to the aft strut bungee during transport.

First ever painted & covered assembly!

It's just all white now, but my Goat is officially covered and assembled in a flight configuration!

The aileron pushrod exits from the covering bind with the linkage, so the stick did not move the ailerons without excess pressure ... I'll fix this first.  Hopefully I can just bend the flange over all the way to clear.

It was nice to see that the aileron lines did line up nicely with the inspection panel access to connect the crossover cable.  I had no issue sticking my arm inside to make this connection.

I did not have terrible problems assembling the pins with the covering installed.  It worried me a little this would be tougher not being able to reach through the structure, but concerns were unrealized.  All the cables and pins and things were okay, save for a couple places where the covering made a little "tent" over a nearby bolt head.  Nothing stood out as an actual problem.

The covering and paint definitely added some weight to the wings, which showed up as a bit more aft mass.  When sitting in the seat, I used to be able to lean forward and pick up the tail.  Now the mass is far enough aft of the CG that I really need a person to step on the nose to get the tail off the ground.  It still balances with my mass forward of the wheel when in a flying attitude, so the simple CG check still passes.

I definitely need some trim color, but Mr. Goat looks happy :-)

Goat painting

The wings have been slow progress, but are about to be done later this morning!  I switched away from using old chairs as sawhorses and brought up my workbench table from the basement so I could flip the Goat wing upside down and paint the bottoms.

I have a little tupperware for keeping the mixed paint fresh.  When more is needed, I pour 120 grams of paint into the tupperware, pour in 40 grams of water, mix with a popsicle stick, and then start painting again.  It takes about 3 minutes to cycle a new mix.

The foam brushes have been a bit kludgy.  The 87-cent brushes from the local Home Depot are soft and tended not to last one coat before a cut appeared in the foam.  The 1-buck brushes from Michaels are a bit stiffer and tend to last much longer, but eventually start to come apart and drop foam debris into the paint.  Maybe I'm just trying to use a throw-away product longer than it should be used...

Freshly mixed paint goes on a bit watery, which is awesome for coverage.  As I get deeper into the mix, the paint feels more sticky and takes more effort to spread nicely.  It probably could get thinned back out with more water.  Usually 120 grams of mix is not too much for being sticky if I'm using it all that same day.

The first coat on fabric tends to absorb about twice as much paint as subsequent coats.  Surely this is because the paint is going through the pores and putting coverage on both the outside and inside.  After that first coat dries, the subsequent coats only put paint on the outside and thus stretch much farther over more surface area.

I estimate that painting Goat has been about three quarters of a gallon of the Glidden Gripper white primer paint.  Some of that mass certainly off-gasses and does not count toward the final airplane weight, but this is still roughly 10 pounds of mass for paint.  Recall I'm using three coats total on every surface (except the bottom of the wings that will not see the same UV load).

Between coats two and three, I have been using 180 grit sandpaper (lightly!) over most of the surface area to knock down any dust or bumps in the paint layer.  It takes extra special care at any hard corners to not sand through the fabric -- basically, don't sand at corners. 

The last coat is drying now, then I'll do an assembly with the whole of Goat covered later today.  Stand by for a cool photo!