04/05/07

Twinstarr 19 Kit Assembly

( Please note Assembly photo links are on the LEFT of this page. To return to the Main Page click back arrow or HERE.)

Twinstarr Kit #19 was purchased from Farrington Aircraft by Ben Bushong.

Here is a photographic log of his progress so far.

Log entry's:

The Plan:  Complete the Twinstar gyroplane fuselage within the next two months.  During that time, acquire a Mazda 13B Rotary engine, preferably turbocharged, and modify it for mounting on this gyroplane.  Modifications will include removing most of the sensors, and installing aviation-specific fuel and ignition controls from Real World Solutions.  Along with this, I'll have to come up with engine mount and exhaust system designs and fabricate them (or have them fabricated).  The propeller that I'm planning on using is the Warp Drive 68 inch, 4-Bladed ground adjustable, and the rotor is the RAF 30 foot, as recommended by Don Farrington at Farrington Aircraft.  Remember, this is just a plan at this time, and is subject to changes.

Change 1:  Make it three months.  Got a trip in February (all month) where I'll be going through withdrawal.

Change 2:  Trip in Feb didn't happen.  Got a trip for three weeks in March, though.  Same plan.

Change 3:  68" 3 Bladed ground adjustable is the propeller that I'm planning on using.

1 Jan 2000:  Put a down payment on the basic Twinstar kit, hopefully to get the airframe in a couple of weeks.  The structure is tack-welded, and needs final welding before I pick it up.  Should be able to get that, landing gear, and wheels in a couple of weeks so I can clean it up and paint.

2 Jan 2000:  Visited a few salvage yards, looking for 13B engines.  Only saw one RX-7 in the 86 and later years, and it didn't have an engine.  Found three in the earlier years, 80 to 85, but those have the 12A engines, so I'm thinking about trying to get one good one out of the three.  Problem is, those are carbureted, not fuel injected, like the 13B, and don't supply as much power.  Guess I'll keep looking for a 13B, and maybe get the 12A's to play with.

14 Jan 2000:  They're still welding the airframe, so I'm thinking I'll get the kit next weekend. 

31 Jan 2000:  Picked up the gyro kit this evening.  Packed everything in the back of the truck and front seat.  Talk about packed!  The fuselage extended just past the tailgate hinge, as did the enclosure.  The big pieces fit in the back, while everything else went in the front.  It was pretty packed, to say the least.  I got back from Paducah, and went directly to John's place to unload.  He happened to be there (he was supposed to be on a trip), and helped move things around and make more room.  I immediately started looking over the parts, sorting out what I would bead blast and zinc-chromate right off the bat.  First task that I want to complete is to get the fuselage up on wheels and take it to get painted.  This will be a great load off my mind.  Several pieces got bead-blasted and primed tonight (toe brakes, rudder pedals, nose gear, etc.).

  Fuselage up on jack-stands, various parts hanging from the tower drying.
More parts, etc.
Wheels, tires, instrument panel.
More pieces parts!
Fiberglass enclosure (nicely done, I'd say.  Only a little filling/finishing needed on this.
Various smaller parts after the primer has dried, just waiting to be final paited!
 

1 Feb 2000:  Continued bead-blasting smaller parts that will fit in the cabinet, then priming them and stashing them away.  Continued the massive task of inventorying all of the parts for each subsection.  Of course, as I was inventorying, I'd notice little parts that weren't too dificult to do, and that wouldn't take too long right now, and went ahead and assembled them.  The push-pull tubes for the toe brakes and rudder pedals came about this way.
First rivet being driven!!  Brand new rivet gun, too!
Finished push-pull tubes.
Rod-ends closeup.  Not the best rivets I've ever shot, but they'll do just fine.

2 Feb 2000:  Put up plastic around the work area, so that my paint spray doesn't get all over everything in the garage, like John's tools, motorcycle, etc.  I figured that before I started priming the fuselage, I needed some type of barrier.  We took 1x2 lumber and drop cloths (plastic 10 x 20 ft, 1 mil), stapled the plastic to the 1x2's, and fastened them to the ceiling with drywall screws.  We fitted a blower with a couple of hoses, and ran the hose under the garage door for an exhaust.  Worked well for low volume painting.  I'm planning on taking the machine to a body shop for painting; I'd rather pay the money and have it done right.  At this point, I'm more concerned about rust than looks.  Anyway, primed the majority of the lower fuselage (didn't get to the tower tonight).  Sanded quite a bit, where there was slight surface rust, then wiped everything down with lacquer thinner, and shot it with zinc-chromate primer.  Tomorrow I plan on priming the gear legs and installing them, and hopefully getting the machine up on wheels.
View of the primed fuselage.
Another view of the same.
View of the plastic barrier that we put up.  Works pretty well so far.

3 Feb 2000:  Installed the landing gear socket assembly, then the spring steel landing gear into the sockets.  That's some pretty tough stuff to drill!  Finally figured out that very slow RPM's and lots of pressure are required to drill those legs.  Once I changed my ways and slowed down, I had no more trouble.
Left landing gear area, showing socket attachment points to fuselage.
Left wheel with brake installed.
Left socket/landing gear.
Right landing gear, without wheel or brake installed.

4 Feb 2000:  Installed the pedals/interconnecting pushrods, rear seat bottom (temporarily for painting), right brake and main wheel, nose gear.  All of this went relatively smoothly, no hitches.  After I was done with these tasks, I went ahead and installed the bellcrank bearings into the bellcranks, which was pretty fun.  I enjoy any riveting that I get to do on this machine.
Front pedal installation, with nose gear visible..
Rear pedal installation.
Left gear with brake hose installed.
Right gear with brake hose installed.
Misc pictures of the bellcranks.
Finally up on wheels!!  The part on the tower is the tail support, with primer drying.

5 Feb 2000:  Not a whole lot happened today, just cleaned up a little, rolled the plastic up and attached it to the ceiling for later use.  Swept (or attempted, anyway) to sweep the zinc-chromate primer dust from the floor, and straightened up a little.  I'm about to the point of getting this machine painted, but still haven't decided who will do it.  I'd RATHER paint it myself, if I can find a booth.

8 Feb 2000:  I decided to have the fuselage painted by a painter up here in Hopkinsville, KY.  Pretty good deal to get it done professionally, and I'll be paying less than I would if I rented the paint booth on Fort Campbell for a DAY.  It's in the shop now, should be out this weekend, then I can get down to some real assembly.

10 Feb 2000:  I happened upon a metal shear that will cut my 1/4" x 24" x 48" sheet of aluminum.  This plate will become my mounting system for the engine, once I dress it up and cut some holes in it.  Believe me, it takes a pretty good size shear to cut this stuff.

11 Feb 2000:  Finished up the engine mount plate and bead-blasted it.  Now, I need to come up with a system to connect that assembly to the rear of the fuselage, and work some isolation mounts in there somewhere.  Also fabricated the cover plate for the oil injection pump that I removed in favor of pre-mixing oil with gas.  This cover, also, is made from 1/4" aluminum plate.
Engine mount plate as it will be installed (engine inverted).
Better view of the 1/4" aluminum plate.
One more view.

12 Feb 2000:  Took a trip to Paducah today to pick up some more parts, mainly miscellaneous nuts and bolts that I had messed up (inch-lbs, not foot-lbs!), or that weren't included due to changes in the kit over the last few weeks or so.  Picked up some engine isolation mounts, and checked them out when I got back to John's, and believe they'll work very nicely.  Now I have some points to start with for the structure of the mount itself.  All of the dots are there; I just have to connect them.  I ordered the rotor blades today from Don Farrington (RAF 30'), also.  The fuselage should be ready to pick up tomorrow morning.

13 Feb 2000:  Got the fuselage back from the paint shop today.  He did a heck of a lot better than I could have, considering I'd have runs all over the thing.  I already had several runs in the primer, so I didn't want to tackle the paint booth issue.  He gave me the rest of the can of white paint, and I got an air brush that did a fantastic job of throwing some more paint on the spots he missed.  There were a few light spots, but the majority of the machine looked good.  Like I said, much better than I could have done.  Once back at John's, I started in on brake lines and standoffs.  I got the external lines done and mounted, but cut a little too much on one of the internal lines and it ended up too short, so I'll have to get some more aluminum line.  No big deal.
Left brake lines with standoffs.  Those standoffs are old rubber hose... They'll get replaced with clear tube.
Right exterior brake lines with standoffs.
The next task was the rudder controls.  I already had the stabilizer socket installed for painting, and left it in for the bellcrank installation.  I'd recommend installing the bellcranks with the socket assembly off of the fuselage.  The washer stackup was difficult at the weird angles; the way I worked that out was to install the bolt from the bottom, carefully placing the two spacer washers on the bolt, then the bellcrank, then the top two spacer washers, and pushing the bolt on up.  Then, I took a -416 washer on another pivot bolt and pushed the first bolt (upside down) out with the second bolt.  This one is now installed the correct direction.  I then put the lower -416 washer and self-locking nut on, and that one was done.  I did the same type of thing for the rear pulleys, also.  This is the first time I've done cables, but they turned out pretty good.  The first two ends that I made didn't come out the best because I didn't grind down the points on the thimbles.  The rest of them worked very well, as I ground the points off.  Centering and locking the tie-link was accomplished by taking a 1/2" by 4 1/2" (approx) piece of .032" aluminum and drilling two 3/16" dia holes on 3 13/32" (I believe... can't remember now) centers.  These pieces then fit between the bellcrank input pins and the pulley pivot bolts.  They both fit in without further alteration, and locked that section in place.  The forward pedals were done with wood blocks and c-clamps, so they wouldn't move at all.  I ran the cables, cut off the excess, and shrink-wrapped the ends to prevent fraying.
Second (middle) pulley on right side.  I fabricated the keeper that goes around the pulley/cable.  The bolt that you see is to plug the fuel tank for leak tests.
Third (rear) pulley on right side.
Cable connection to right forward rudder pedal.
Rudder tie-link installed, looking down from rear of fuselage.
Tie-link looking down from front of fuselage.

14 Feb 2000:  All evening I worked on the wood floorboards and sheet aluminum scuff panels.  They came out pretty nice, as you can see by the photos; I'm pretty happy with both of them.  The cutouts in the manual are pretty accurate, but still needed quite a bit of tailoring to fit around the pedals without contact.  Most of the cuts I made with a bandsaw, but used a router with a plunge bit to cut out the holes for the cyclic sticks.  Very carefully, with the router, I trimmed the wood up to my pencil lines and sanded, once the cutouts cleared the controls.  The front scuff panel needed some trimming because of the taper of the fuselage, and I just laid the piece between the lower longerons, and set a 6" machinist's rule along the longeron on each side, to mark a 1/2" clearance for a cut line, so the edges of the panel parallel the longerons.  Spaced the holes around the panel, drilled 1/8" holes and countersunk for the short countersunk screws.  Very tedious, but enjoyable work.  I plan on sealing floorboards with sanding sealer, then staining with a dark stain.  Should look nice.
Pictures of the rear floorboard and scuff panel, screws not installed.
Shots of the forward station floorboard and scuff panel.

18 Feb 2000:  Sanded and stained the floorboards, and sealed them with a spray-on exterior sealer.  Installed the front floorboard, but haven't permanently installed the rear, due to the fuel tank not being completely installed yet.

19 Feb 2000:  Went to Paducah and picked up the flight control torque tubes and mixing unit.  Disassembled the unit and painted the tubes and mixer.  Assembled the control tube sockets and control sticks, which was more of a major undertaking than I figured it would be.  The control sticks were just about exactly the same size as the socket, so it would go in easily, but the metal would gall and lock up, where the stick wouldn't come out.  With quite a bit of sanding and wire brushing, I got the clearance where it should be, and they go in and out fine.

Also received the rest of the parts for the seats, and built the seat backs.  This was very straightforward, and the seat covers fit perfectly.  I haven't built the back seat bottom yet, because I don't have the fuel tank mounted yet.  Still dreaming of a plan for that.  At least I can sit in the front seat and act like I'm flying!
Front seat bottom cushion
Front seat completed.  Pretty nice installation for the seats.

20 Feb 2000:  Reassembled the torque tubes and control sticks, torqued all bolts (AN4), and torque-sealed them.
Front and rear control stick installations.
Various control installation shots.

23 Feb 2000:  Assembled the lower rotor push-pull tubes from aluminum tube, aluminum rod end inserts, and adjustable rod ends.  These were basically the same as the earlier ones, for the rudders and brakes.  Not a big deal.  The tubes were already cut to length, so all I had to do was drill three holes (plus a witness hole) per end, and shoot #4 universal rivets to fasten the rod end insert.
Pushrod pieces, and a completed rod end for the lower pushrod.
Lower pushrods installed to the mixing unit and idler arms.

26 Feb 2000:  Hung the engine where it needs to go, started dreaming of ways to attach that thing to the back of the machine.  Ended up trying to dream up a way for about a week, and finally decided on a method.  Might be more complex than most people would go for, and I think if I have to remount the engine, I'll go with a method that doesn't require quite so many welds.
Mmmmm.  This looks about right.  I did measure some things!

1 Mar 2000:  Started cutting pieces for the engine mount.  My plan is to use the isolation mounts at the front of the engine mount, and mount the engine hard to the mount.  The 1/4" aluminum plate will get sandwiched between the upper and lower mounts.  I borrowed a friend's portable MIG welder so that I could tack weld the assemblies on the aircraft.  Throughout, I had the smaller individual assemblies (forward upper, forward lower, and the upper and lower rear assemblies) TIG welded by a friend, so that I could temporarily mount them, and know that's how they would go together at completion.
Individual parts for the upper forward and lower forward sub-assemblies.
Interesting part here.  A plate actually is attached through the intake manifold.
Right and left lower rear mount assemblies.
 

9 Mar 2000:  Finished cutting my pieces, and tack welded everything together.  For the first time, the engine was off of the hoist, and actually mounted to the aircraft for a few minutes.  I didn't leave it there long, as the welds were only tacks, but it did support the engine.
Tack welded engine mount, complete.
Assembled mount, left side, with plate installed.
Front view.
Right side view.  Notice the plate that gets sandwiched between the intake manifold parts.
Rear view.

11 Mar 2000:  Final welding is complete on the engine mount as it will go on the aircraft.  What a load off of my mind!  Now it gets painted and installed.

12-14 Mar 2000:  Painted the engine mount, and mounted the engine.  Looks pretty good.
Right and left views of the engine, mounted on the airframe.
 

15 Mar to 8 Apr 2000:  Been working on the gyro on and off, staying up late, getting in late, and not taking many pictures or updating these pages.  I have several pictures on disk, but haven't worked on them to get them on the page.  I'll keep working on that, and will have them up one of these days.

During this time, I built a sort of "firewall" in front of the engine to mount accessories on, and to put something between the passenger/push-pull tubes and the dual accessory drive belts on the engine.  Also, the coils are mounted to the left and right sides of the fuselage behind the passenger seat, to .050" aluminum sheet panels attached by DG-14 cushioned clamps.

I accomplished fuel tank mounting by fastening 1 1/2" square angle on each side of the fuselage under the back seat, to the tabs, as designed.  The forward ends of the angle are fastened together via angle sheet across the front on top and bottom, with 2 each 1/8" spacers in the middle.  This was riveted together with flush rivets.  The sheet angle on top was positioned to restrain the tank from forward movement.  On the sides, more formed angle was riveted to restrain side movement, and two smaller pieces at the rear of the 1 1/2" angle for rear restraint.  The fuel tank fits securely into the fitted angles.  I took care of upward restraint by using two turnbuckles attached to DG-14 cushioned clamps around the lower frame rails, up to a 1" strap of .040" thick 4130 steel.  This strap is encased in a rubber channel from Wicks, designed just for this.  The strap runs across the top of the tank, pre-bent for the corners of the tank, and attached to the turnbuckles with clevis pins/washers/cotter pins.  The turnbuckes are tightened up evenly, and everything is very secure.
Bottom right side from underneath.
Strap and turnbuckles, left then right side.
Angles from above, showing engagement on step of tank.
Front angles, showing two spacers.
Front right corner, and front left corner from bottom.
 

9-10 Apr 2000:  Went to Paducah and got schooled up on the changes  that went into the tail section.  Got a good part of it built, and will continue to work on the tail sections when I get back home.

11-22 Apr 2000:  Continue to work on the tail sections.  The vertical stabilizers are built, ready to rivet, once I get the holes ream-drilled to #30.  After buying around 300 Clecos of 3/32 and 1/8 inch, I finally have nearly enough!  Man, takes a bunch to do it right.  I'm waiting on some nutplates before I build up the horizontal stabilizers, as the one I received weren't correct.  I've got the correct ones ordered, and will continue with the the horizontal stabs once I receive those.  I have all of the parts required for the rudders, and just need to put them together and rivet them up.

Vertical stabilizers temporarily assembled, with one rudder.
Various pics of vertical stab.
Rudder frame, and temporarily assembled rudder.
Yellow panels on sides have the coils mounted to them.
Another issue that I was waiting on for the vertical stabilizers was a spacer through which the bolt passes and clamps to the horizontal stabilizer.  Nothing was shown, so I queried Farrington Aircraft, and came up with an idea of using a 3/4" x 1" x 1 15/16"  block of aluminum, epoxied between the nose ribs, centered on the cutout hole for this bolt.  Once this assembly is glued up fast and everything is aligned, I started a hole in the block, centered in the cutout in the ribs (round cutout about 3/8" diameter).  Making sure it was perpendicular (easy to do with a #30 x 6" bit), I drilled about half way down.  Turned the stabilizer over, and started on the other side, until the holes met in the middle.  Reamed them with a few passes from the drill, then drilled again once through with a #10 bit.  It should be possible to bolt this up tight without fear of crushing the vertical tail.  Now, it's ready to put together for the last time.

26 Apr 2000:  Assembled the left vertical stabilizer with solid rivets where I could get them in, and Cherry Max for the blind areas.  Total rivets used for a single vertical stabilizer was approximately 370.  I used 122 Cherry Max 4-2 rivets, which was more than I had planned on for the entire tail.  Getting expensive, buying those things.  I trust them a whole lot more than pop rivets, though.  Having been a sheet metal guy when I was enlisted, I know that they work, and that they're strong.  I believe it's worth the price, though.  The foam core (2" thick insulation) is double-sided taped, and the skins are double-sided taped, and then the thing is very carefully aligned before any of the tape touches other tape.  The rear outboard skin didn't go on very smoothly, and I had to redo the tape.  Second time was a charm.  The first nose skin went on smoothly, but the other one was a problem, just because the foam kept tilting out and touching the skin.  Finally went together and the rivets went in, until I ran out of blind rivets.  Needed 22 4-2s, and 9 4-3s.  Other than that, the stabilizer went together pretty well.

27 Apr 2000:  Took the stabilizer to work and used one of the Cherry Max pullers to pull the last 31 rivets.  Borrowed rivets from a DynCorp guy until my next order comes in.  I've got plenty of 4-1s, ordered 150 of those, then used about 20.  Ordered 100 4-2s, and used them all, plus 22, on the first vertical stab.  Didn't order any 4-3s, need 9 per stab.  I think I've got plenty ordered, now.

Shot the solid rivets in the right vertical stabilizer, taped the rear foam, and assembled the second skin.  Ran out of time, and had to leave the assembly as it was.  Tomorrow I'll finish up the right vertical stabilizer, and, time permitting, mount them on the airfram so I can build the horizontal stabilizers to fit in place.

Assembled the nut plates and fittings onto the tip ribs for the horizontal stab.  Once I get the vertical stabs installed and bolted straight, I'll temporarily install the tip ribs for the horizontal stab, bolted in place, just like they'll be when finished, then take my measurements, or just build the stabs using the aircraft as a jig.  Might be tricky, but at least the parts will be a guaranteed fit.  We'll see how it all works.