Visit to Torrey Pines, turf of the Goat

I made a trip to San Diego and took Sunday morning to visit Torrey Pines Gliderport!  There was an outside chance to catch Floyd Fronius and his newest Goat X at the cliff.  No such luck, but it is awesome to now understand the home of the Goat.

Torrey Pines is a massive 300ft cliff right along the Pacific Ocean.  On arrival at 10:00, the grass was quiet.  After an hour or so to hike on the beach below (beware the sunbathers) the grass above was starting to come to life as the wind slowly picked up. 

The RC sailplane area was a wonderful sitting spot to watch the paragliders kiting and then steadily launching off the cliff.  It started with a couple of guinea pigs in the light air, and then more followed as the wind filled in.  There were over a dozen gliders aloft at the same time.

Relocating to the Cliff Hanger Cafe for lunch was a short walk and gave a different view.  The tandem pilots would meet their fare in front of the cafe, clip them in, and launch within minutes.  It looked like a blast.

Torrey was amazing.  I am inspired (and slightly sunburned).  

My Goat really needs to get some air beneath the wings.  First cuts were literally 18 years ago...

Vario purchased!

An LxNav S3 is now in the mail (edit --- out of stock!!).  It is a mechanical needle and not the latest tech (S10 or similar), but it is only a total energy pressure input, which will be insensitive to just how slowly the Goat flies, rather than an airspeed pressure sensor set up for glass ships.  Airspeed pressure scales poorly for the low-speed range, but total energy is close to static and it is the same pressure sensor for fast and slow-speed sailplanes.  The S3 is also self-contained with a speaker, so I just need to add power and (desired) connect to a total energy probe.  Static pressure will be close enough to total energy for my purposes, so this will also functionally serve as an altimeter.

And an ICOM A13 is also in the mail.  This is the "don't hit me" radio and should have been the first radio purchase anyway.

Navigation will be easy enough with a phone app.  There is no way I'll range away from beyond sight of the airfield for now, so the phone will be plenty sufficient.  And I already have the phone...

To-do's before the first flight are now:

1. do a weight & balance
2. do a very thorough pre-flight check
3. airband radio 
4. variometer 
5. finish weld trailer frame joints

Deferred:

• wing root kiss seal
• leather patch on wing tips where they rub the ground
• leather patch guides for elevator control lines
• trim color paint
• main strut fairings
• jury strut fairings
  
• emergency parachute
  
• drogue chute

 

Radios purchased

In trying to keep moving, I finally bought some radios for airplane / truck communications.  They are some inexpensive GMRS handsets to stay off of airband.  This may not be the final answer, but that's a starting point for having a conversation about a first flight.

Not many items are left in the to-do list... 

To-do's before the first flight are now:

1. do a weight & balance
2. do a very thorough pre-flight check
3. acquire radios (need 1x in car, 1x airborne)

Deferred:

• finish weld trailer frame joints
• wing root kiss seal
• leather patch on wing tips where they rub the ground
• leather patch guides for elevator control lines
• trim color paint
• main strut fairings
• jury strut fairings
  
• emergency parachute
  
• drogue chute
• variometer

Random welding side-project for a friend

Nothing Goat related, but I had a chance to weld some 316 stainless steel brackets for a friend.  The welds are grey (too much heat, not enough post-flow time), but they are stuck together.  Hopefully this works out for his boat.  Welding steel is so much easier than aluminum.

 

 

Upper rail welding done

The fall weather was excellent and Saturday is a day for welding.  This was a to clear an item from the to-do list.  The upper rail joints looked like this one, only partially welded.

My best joint was probably this one, which looks almost respectable.  The others aren't nearly as photogenic.

To-do's before the first flight are now:

1. finish weld the upper rail to the vertical supports
2. do a weight & balance
3. do a very thorough pre-flight check
4. acquire radios (need 1x in car, 1x airborne)

Deferred:

• finish weld trailer frame joints
• wing root kiss seal
• leather patch on wing tips where they rub the ground
• leather patch guides for elevator control lines
• trim color paint
• main strut fairings
• jury strut fairings
  
• emergency parachute
  
• drogue chute
• variometer

 

Mobility!

The entirety of Goat has been mobile for the first time!  The wing were strapped into the trailer with ratchet straps, and the struts and tail were strapped to the cross-beams with Velcro.  The horizontal tail sat atop the upper wing and jammed in-between the wing and flap/ailerons.  

 

The nose section was in the back of the sporty Prius-mobile.

With the tail section 'backwards' to the airflow, the rudder looked a bit wiggly at 45mph.  I'm sure there will be a better placement for each of the components, determined from some trial-and-error.  

The trailer rode reasonably well with the weight of the plywood and the stiffness of fully trussing the structure.  I could probably get away with the current welding, but it would make me feel much better to weld everything completely.

The upper wing mounts could be about 1in higher and still leave ample room.  The 1in square tube isn't quite large enough for the hitch pins to hold securely, so it would be nice to replace them with 1.25in square tube instead, and moving them up at the same time.

To-do's before the first flight are now:

1. take all of Goat for its first trip around the neighborhood 
2. finish weld the upper rail to the vertical supports
3. finish weld all the trailer joints
4. do a weight & balance
5. do a very thorough pre-flight check
6. acquire radios (need 1x in car, 1x airborne)

Deferred:

• wing root kiss seal
• leather patch on wing tips where they rub the ground
• leather patch guides for elevator control lines
• trim color paint
• main strut fairings
• jury strut fairings
  
• emergency parachute
  
• drogue chute
• variometer

A mount for the lower wing, installed

The lower wing mounting system is now installed and a wing panel seems to be reasonably okay on it.  It will need some tweaking over time, but I can move the mounts with a simple 1/4-in drill bit.  It really would be nicer if the ailerons folded flat (my fault, not the drawings)...

This is how the lower mount looks with a wing panel installed in the trailer.

The lower wing panel is well secured by three Velcro straps and is constrained by the cross-braces for the upper wing.

The lower mount bar has a long end for wrapping the strap around.  I made the upper and lower beams interchangeable, hence the extra hole visible.

To-do's before the first flight are now:

1. install lower wing mounts into trailer
2. finish weld the upper rail to the vertical supports
3. finish weld all the trailer joints
4. take all of Goat for its first trip around the neighborhood 
5. do a weight & balance
6. do a very thorough pre-flight check
7. acquire radios (need 1x in car, 1x airborne)

Deferred:

• wing root kiss seal
• leather patch on wing tips where they rub the ground
• leather patch guides for elevator control lines
• trim color paint
• main strut fairings
• jury strut fairings
  
• emergency parachute
  
• drogue chute
• variometer

A mount for the lower wing, parts

 

After a break that included travel to a crazy hot desert, crazy far north, and beautiful Vermont, I had a idea for a mounting system for the lower wing in the trailer.

On a rainy Saturday evening, a quick trip to the giant orange home store for aluminum square tube (oh so expensive) sets me up with some material.

I'm planning to run a long bolt through just the wood deck, so there is no drilling through the aluminum frame.  This is what it'll look like:

I'm ready for daylight to try mounting this to the trailer.

I also made it out to get more Argon for the remaining trailer welding, so that's also in the work queue.

To-do's before the first flight are now:

1. install lower wing mounts into trailer
2. finish weld the upper rail to the vertical supports
3. finish weld the trailer frame joints
4. take all of Goat for its first trip around the neighborhood 
5. do a weight & balance
6. do a very thorough pre-flight check
7. acquire radios (need 1x in car, 1x airborne)

Deferred:

• wing root kiss seal
• leather patch on wing tips where they rub the ground
• leather patch guides for elevator control lines
• trim color paint
• main strut fairings
• jury strut fairings
  
• emergency parachute
  
• drogue chute
• variometer

Some trailing edge wedges

Let's glue together some trailing edge wedges together toward creating a fairing for the aft strut.

Several years ago, I made a small section of the fairing and covered it with fabric.  It holds up reasonably well, but fiberglass will be more rigid than the fabric.  This is the staring point.

 

It took a few hours to clean up the pile of trailing edge foam pieces with a sharp x-acto and a sanding block.  There is nothing like the accomplishment completing a pile of monotony. The effort was to remove the little bridges and other nibs so they could be glued together in sections.

I decided to make the trailing edge in 18in sections.  These will eventually be covered with lightweight spackle, sanded smooth, and glassed.

The thought occurred to me that making a thin-walled fiberglass tube over a section of scrap aluminum would allow sliding a fairing section over the strut.  That thin tube would also give a bonding surface for the leading edge pieces, so the whole fairing could be an add-on part.  This sounds like more work.  We'll see.

In case you're counting, it took about 136 individual trailing edge wedges for the aft strut.  I'll do a final count later.  Multiply this by two for the leading edge of the aft strut, then multiply by two for the opposite side, then multiply this by two for the forward strut.  That'll be around 1000 individual pieces of foam.  I hope this is worth the effort! 

A bunch of foam

It was way too humid, hot, and sunny to work in the backyard on trailering the wings.  So, I cut a whole bunch of foam pieces on the CNC toward making main strut fairings.  Leading edges and trailing edges are cut similarly, and a whoooole bunch of them from one sheet of 1in thick foam.  The struts are around 12ft each.

 It's too hot in the garage, so that's all for today.

Second coat

Not much to show of a second coat of paint.  It's more consistently gray.

A good friend looked at the nose release and called it functional.  The conversation quickly zeroed in on if there was a more secure way to hold the release pin than the two hair-ties.  This may be a case of perfection is the enemy of good enough, however.  It works.

Summer weather of extreme heat, humidity, and direct sun has arrived in force.  To hide from the heat, I'm taking a second look at the strut fairings.  These aren't required for the first flight, so consider that I could be stalling a bit.  No pictures today.

To-do's before the first flight are now:

1. figure out how all of the Goat parts transport together -- lower wing, horizontal tail
2. take all of Goat for its first trip around the neighborhood 
3. finish weld the upper rail to the vertical supports -- need Argon
4. finish weld the frame joints -- need Argon
5. do a very thorough pre-flight check
6. do a weight & balance
7. get radios -- need 1x airborne, 1x in car

Deferred until after the first-flight:

• leather patch on wing tips where they rub the ground
• leather patch guides for elevator control lines
• trim color paint
• wing root kiss seal
• main strut fairings
• jury strut fairings
  
• emergency parachute
  
• drogue chute
• variometer

Lower wing on the trailer

It isn't clear yet how the lower wing mount will work.  There isn't room for foam padding.  I'm still mulling how this will work.  It may help to add pad eyes rather than looping Velcro all the way around the wing and trailer.

To-do's before the first flight are now:

1. figure out how all of the Goat parts transport together -- lower wing, horizontal tail
2. take all of Goat for its first trip around the neighborhood 
3. finish weld the upper rail to the vertical supports -- need Argon
4. finish weld the frame joints -- need Argon
5. do a very thorough pre-flight check
6. do a weight & balance
7. get radios -- need 1x airborne, 1x in car

Deferred until after the first-flight:

• leather patch on wing tips where they rub the ground
• leather patch guides for elevator control lines
• trim color paint
• wing root kiss seal
• main strut fairings
• jury strut fairings
  
• emergency parachute
  
• drogue chute
• variometer

 

Skid Plate Upgrade

Expecting that the first flight will be from an old paved runway, the aluminum skid plate will take a beating.  It has already showed some scrapes from moving around the garage and driveway.  So, on another rainy weekend day, it was time for an upgrade.

I had some leftover 1/8in Delrin from the trailer.  A quick trip to the bandsaw, I had a couple strips 3/4in wide to match the metal skid plate.  Transferring the 1in hole spacing into them, and drilling out nine rivets with a #30 drill bit, they were easy to Cleco into place.  A few Cherry pull rivets and it's all done.  It looks reasonable.  Quick projects are nice.

To-do's before the first flight are now:

1. figure out how all of the Goat parts transport together
   
2. take all of Goat for its first trip around the neighborhood 
3. finish weld the upper rail to the vertical supports -- need Argon
4. finish weld the frame joints -- need Argon
5. do a very thorough pre-flight check
6. do a weight & balance
7. get radios -- need 1x airborne, 1x in car

Deferred until after the first-flight:

• leather patch on wing tips where they rub the ground
• leather patch guides for elevator control lines
• trim color paint
• wing root kiss seal
• main strut fairings
• jury strut fairings
  
• emergency parachute
  
• drogue chute
• variometer

Deck painted

The rain gave way to sunshine (and humidity), so I finished the first coat of paint on the trailer deck.  It's very grey.  I like it!

The guide tubes for the tow release line have been bonded onto the nose tube. I made a simple tee for a pull handle.

To-do's before the first flight are now:

1. figure out how all of Goat parts transport together
   
2. take all of Goat for its first trip around the neighborhood 
3. finish weld the upper rail to the vertical supports -- need Argon
4. finish weld the frame joints -- need Argon
5. UV paint on the plywood decking -- partial first coat, second coat is needed
6. glue tow release line tubes to nose tube
7. do a very thorough pre-flight check
8. do a weight & balance
9. get radios -- need 1x airborne, 1x in car

Deferred until after the first-flight:

• leather patch to wing tips where will rub the ground
• leather patch guides for elevator control lines
• trim color paint
• wing root kiss seal
• main strut fairings
• jury strut fairings
  
• emergency parachute
  
• drogue chute
• variometer

Releaseable at both ends

The tow rope now has release mechanisms at either end, so the pilot can release, or the truck can release in an emergency.  

I'm not totally sold on the way the weak link routes, but I'm sure this will survive first flight.  I'm also sure that the first several flights will tweak things.  If any hang glider pilots out there have strong opinions about this photo, please leave a comment.

The topside paint from Total Boat arrived and I got a small section of the trailer deck painted.  Surface prep with a 120-grit sandpaper and a thorough cleaning with isopropyl alcohol seemed reasonable.  The first coat went down smoothly. The paint itself smells like kerosene.  It is going to make a huge difference in visual finish to add the consistent color.  It will also protect the plywood much better than my hit & miss epoxy job.

The list is getting mighty short now.  This weekend is rainy, so the back yard is a soggy mess.  The preflight, weight and balance, and trailer finishing work will all wait until next weekend at earliest.  We'll see.

To-do's before the first flight are now:

1. figure out how all of Goat parts transport together
   
2. take all of Goat for its first trip around the neighborhood 
3. finish weld the upper rail to the vertical supports -- need Argon
4. finish weld the frame joints -- need Argon
5. UV paint on the plywood decking -- partial first coat, second coat is needed
6. sort out plane-side weak link and release
7. glue and tape tow release line tubes to nose tube
8. do a very thorough pre-flight check
9. do a weight & balance
10. get radios -- need 1x airborne, 1x in car

Deferred until after the first-flight:

• leather patch to wing tips where will rub the ground
• leather patch guides for elevator control lines
• trim color paint
• wing root kiss seal
• main strut fairings
• jury strut fairings
  
• emergency parachute
  
• drogue chute
• variometer

Better with a fid

With a splicing fid, a better splice you can make.

The eye splice looks so much better than a knot.  This end of the tow rope is now done.  I will simply take the splicing fid on the first flight to put the eye splice in the other end, lest I unravel 1000ft of rope and can't get it back on the spool as cleanly!  If the weak link turns out to be too strong, tying a single loop in each end (rather than having a loop double) will halve the force.

To-do's before the first flight are now:

• figure out how all of Goat parts transport together
  
• take all of Goat for its first trip around the neighborhood 
• finish weld the upper rail to the vertical supports -- need Argon
• finish weld the frame joints -- need Argon
• UV paint on the plywood decking -- paint arrived
• put eye splices in tow rope ends
• sort out plane-side weak link and release
• do a very thorough pre-flight check
• do a weight & balance
• get radios -- need 1x airborne, 1x in car

Deferred until after the first-flight:

• leather patch to wing tips where will rub the ground
• leather patch guides for elevator control lines
• trim color paint
• wing root kiss seal
• main strut fairings
• jury strut fairings
  
• emergency parachute
  
• drogue chute
• variometer

Weak links

I've been trying to figure out the attachments for both ends of the tow rope.  Based on today's research, it appears common for sailplanes to have a weak link on both ends, including a 25% higher load rating on the tow-plane side.  It appears common for hang gliders to have two releases for redundancy.  Lots of learning.

Here is what I've come up with for the car side.  I have a fid on order to do an eye splice in the rope (yellow).  The eye can accept a pre-made weak link loop (neon yellow) with a double lark's head knot.  The welded ring can be put onto the loop with a single lark's head.  This setup mates the release to the rope.

On the airborne end, I'm working toward the as-designed release mechanism.  A parachute release pin is in the mail, and after "borrowing" a hair loop from my better half, all the components will be in play.  We'll see how it all looks together next weekend.

To-do's before the first flight are now:

• figure out how all of Goat parts transport together
  
• take all of Goat for its first trip around the neighborhood 
• finish weld the upper rail to the vertical supports -- need Argon
• finish weld the frame joints -- need Argon
• UV paint on the plywood decking -- paint arrived
• buy weak-links and end rings
• put eye splices in tow rope ends
• sort out car-side weak link and ring
• sort out plane-side weak link and release
• do a very thorough pre-flight check
• do a weight & balance
• get radios -- need 1x airborne, 1x in car

Deferred until after the first-flight:

• leather patch to wing tips where will rub the ground
• leather patch guides for elevator control lines
• trim color paint
• wing root kiss seal
• main strut fairings
• jury strut fairings
  
• emergency parachute
  
• drogue chute
• variometer

Curing hangar rash

There is no cure for hangar rash. There is only maintenance...

I patched seven holes in the covering.  Several of these holes came from trying to keep the struts on the wing panels - the eye-bolt heads poked through the covering.  Other holes were from things like bolt-heads in the jury struts and a general tear from I-don't-recall-why.

Patching is an easy affair with the Stewart Systems process and using the 30NF Fastbond from 3M.  I cut out doilies with pinking shears, lightly traced the shape on the covering, put a layer of 30NF and wiped off all the excess.  After it dried, I ironed the patch in place at 110C, then saturated the patch with more 30NF before wiping off all the excess.  After it dried again, ironing at 120C, putting on two layers of Glidden Gripper paint cut with 30% water by weight (15g paint + 5g water), and the repairs were completed.

 

Et voila, gone! 

 Trailer to-do's are now:

• figure out how all of Goat parts transport together
  
• take all of Goat for its first trip around the neighborhood 
• finish weld the upper rail to the vertical supports -- need Argon
• finish weld the frame joints -- need Argon
• UV paint on the plywood decking -- paint arrived

For the first-flight:

• covering repairs
• backyard final assembly and very thorough pre-flight check, including weight & balance
• buy weak-links and end rings
  
• get radios -- need 1x airborne, 1x in car

After the first-flight:

• leather patch to wing tips where will rub the ground
• leather patch guides for elevator control lines
• paint trim color
• wing root kiss seal
• main strut fairings
• jury strut fairings
  
• emergency parachute
  
• drogue chute
• variometer

Tow hitch welding (with the last 20psi of Argon)

The tank had only 20psi amount of Argon left, which was just enough for finishing on one of the first welding projects: the tow hitch release mechanism.  The vertical tab needed fillets.  I originally tried and did not have enough heat (you can see remnants of the failed weld puddle), so today I fix this.

During the previous weld attempt, I was only on a 110VAC circuit, which limits to 120A of current.  Hooking into the 220VAC mains lets me run up to 200A of current, which is more than plenty.

 

 

I welded the vertical tab in place with a new bead all the way around it, including on the bottom, ends, and sides.  The weld bead isn't the prettiest, but it is structural and way better than before.

I also added a tack to the sides of the plates that hold the release mechanism itself.  These vertical plates have tabs that go into slots in the base, and those tabs are welded to the base from the bottom, so this additional tack was mostly for cheap insurance.

After a cooldown period and quick reassembly, the release hitch is ready for duty.  

I also now have 1000ft of yellow polyethylene 1/4in rope for the maiden flight.  Last minor items will be the weak links at either end, tying off, and ensuring the airplane-side release mechanism works reliably.

Trailer to-do's are now:

• figure out how all of Goat parts transport together
  
• take all of Goat for its first trip around the neighborhood 
• finish weld the upper rail to the vertical supports 
• finish weld the frame joints
• UV paint on the plywood decking

For the first-flight:

• covering repairs
• backyard final assembly and very thorough pre-flight check, including weight & balance
• re-weld the tow hitch release (I'm now doubtful it had good penetration) 
  
• buy weak-links and end rings
  
• get radios (1x airborne, 1x car)

After the first-flight:

• leather patch to wing tips where will rub the ground
• leather patch guides for elevator control lines
• paint trim color
• wing root kiss seal
• main strut fairings
• jury strut fairings
  
• emergency parachute
  
• drogue chute
• variometer

Hooked myself

The Goat drawings show a small hook tool that one person can carry a wing panel.  My better half was traveling and I decided to make the tool.  A more typical sailplane assembly aid is a wing cart.  I once bought a small toy from a yard-sale and tried making a wing cart.  It didn't work at all.  So now the hook tool:

 

The hook tool worked to take a wing panel to the back yard to stage for putting into the trailer.  I didn't get a picture of carrying a wing panel because it was just me.  I also couldn't figure out how to get the panel into the trailer myself, so the lower wing mounting will wait for another day.

 

Trailer to-do's are now:

• figure out how all of Goat parts transport together
  
• take all of Goat for its first trip around the neighborhood 
• finish weld the upper rail to the vertical supports 
• finish weld the frame joints
• UV paint on the ply decking

For the first-flight:

• covering repairs
• backyard final assembly and very thorough pre-flight check, including weight & balance
• re-weld the tow hitch release (I'm now doubtful it had good penetration) 
  
• buy weak-links and end rings
  
• get radios (1x airborne, 1x car)
  
• travel
• fly!

After the first-flight:

• add leather patch to wing tips where will rub the ground
• install leather patch guides for elevator control lines
• paint trim color
• install wing root kiss seal
• jury strut fairings
  
• main strut fairings (after flying to figure out the right angles)
• emergency parachute
  
• real variometer (LXNav with a TEK probe is my intention, if it is sensitive at low speed...)
• drogue chute