***********************************Pitts S1 C-GIPS

Repairs and Modifications

2006

 
In 2006 all my local airports went to a Mode C requirement.  I had to install a transponder and selected a Microair T2000 which I powered with a small 4 ah gelcel battery.   After looking at all the Odyssey 680 batteries installed in RV's, I decided to try mounting one permanently to both power the transponder and start the airplane.  Now that there was a battery on board, the old mechanical tach with the two angle drives could be replaced with an electric tach, and there was power to back-up  the handheld radio (Yuasa VXA-220). The APU plug start feature was removed. Old man's airplane now.  The fully charged 680 could start the plane about a dozen times and provide power for probably 10 hours of flying.

Later in 2006 I dropped a valve while flying an Unlimited contest and had to replace a cylinder. First engine work since 1987 and perhaps an omen.  To finish the contest I was offered to fly the Wolf Pitts owned by Bob Higbee. Up against some Zivko 540's I came in second in the Free (my first try at the controls) and then won the Unknown.  Ever since Norm Willis had first shown up flying his SteveWolf custom built Wolf Pitts I had been coveting a try at the handles.  I wasn't disappointed and suddenly my plane needed updating.

 
Antennas installed on the belly. Odyssey 680 battery- modern times

 

2007
Into the 2007 season. While tracking down an oil leak around the front seal I found a cracked crankshaft.  Ken Vike of Vike Aeromotive in Kamloops did the honors. He found a few other issues as well that confirmed that it was perhaps fortuitous to open up the engine while it was parked in a hangar instead of deadsticked into a creekbed.   The "0" time  O-360 B4 wide deck engine looks like jewelry - but it isn't just for show, cranking out 191 hp at 2700 with the high compression pistons.

 
The dye check to confirm a need for further investigation.  Next came a magnetic particle NDT check to conclusively determine a crack. Another Ken Vike masterpiece.  If you need engine work, give him a call at 250-828-9444. <http://vikeaeromotive.tripod.com>

 
In the summer of 2007 at Arlington I saw the Pitts S-1 that Steve Wolf fixed up for his wife Kathy. I liked everything about that plane. Best of all Steve was making components available to "Wolf" any S-1.
RV3 gear, special pressure cowl, trick Wolf ailerons, Owens Composite carbon-fiber prop Altimeter is just an extra safety precaution for spin maneuvers.  Panel is moved back about 4".

 

2008

RV Gear Mod

Engine removed, engine mount sent to Wolf for the RV3 gear mod. Time to pull that old bungee gear off for good.

  

Bungee box removed from firewall, and bungee cord ears ground off.  Landing Gear mount bracket ground off.  Irreversible.

Received the modified engine mount back from Wolf, complete with legs , fairing, wheelpants - note size difference to the ones I had before.
The legs and fairing both painted with red Endura - two-part epoxy paint.  Axles drilled for the castellated nuts using a good cobalt 1/8" bit, a drill press, and a little squirt of WD40.  Made up some RV6 style backing plates to mount the original wheelpants, brake calipers will go on the front again. Had to get some 3/4" longer lower engine mount bolts (AN 6 - 53).
Detail showing relieved lower firewall lip.  Exhaust fits like it was meant to.
Ready for a test flight after a ground run.  I'll do a few flights to proof it out before I close up the gear legs.

Track is now 66", prop to ground clearance is 15.5"with the 76-62 prop

Brake lines are Aircraft Spruce - Nylo-Flow.

 

 
Test flight went well.  Now to finish off the gear leg fairings.

First the top 3 inches of the 29" leg fairing sent by Wolf was cut off and saved to be used as a cuff on top.  The remaining fairing was folded and taped with masking tape and 18 1/8"holes, 1.5" apart were drilled in the trailing edge.  These are for the short aluminium pop rivets to hold it together.  Then 6 #8 nutplates installed in the top to hold the cuff in place. Note, on closer inspection of the Wolf Pitts photographs these could have been done as #6 instead of #8 screws, although I did use three less.  Cuff was shaped to the fuselage.  A single 3/16" hole was drilled on the inside of fairing and a #10 nut plate attached to the inside of the rib.  This will keep the fairing in place.

 

By now everything had  little scratches so I  gave it all another coat of Endura paint before final assembly.  I put blade tape around the forming ribs to allow the fairing to "float" at little better.

That little belly panel between the lexan and the firewall was a complex  piece of .025, but allowed the exhaust to tuck in close.  Easy to remove, and gives access to the brakes.  The little aluminium tubing elbow behind the black vent hose is the fuel tank vent.
Finished.

 

Avionics and Panel

Current view of the instrument panel.

That's a Garmin iQue 3600A replacing the sequence card for cross-country flying.  Garmin 296 would have been better for the task.

Main battery powers transponder and tach, and backs up battery-powered radio and GPS.

Bose-X headset just for the luxury of it.
Battery switch (red lever) moved to below the seat right side.

SPOT Messenger Test

"Spot Messenger" installed for testing.  Automatic Satellite Tracking on cross-country trips, ELT function, "I'm OK" or "I need HELP" messages to a loved one.
Bracket is a simple piece of .032 with a bent ear and some velcro on it.  Slides into a slot made from a piece of .025 between a couple of canopy screws.
Sample from a recent 400nm trip.

Bingo, position reports automatically every 10 minutes to everyone with your web page link and a password.  Plus bookends "I'm OK" messages at the start and finish sent to email addresses and SMS cellphones.

It didn't miss a single report, hit one of the globalstar satellites every time. I'm satisfied.

Sept 2008 - Rerig and re-spade

Post AWAC.  Loose aileron brackets with a few months flying still left in the year.  Tightened them, then removed the spades for a full re-rig.  Time to get rid of that four spade "porcupine" look and go back to two spades on the bottom ailerons.  
Checked Mike Davis' web page to see how he'd done his,  decided on the newer triangle shape, and matched the spade area from the original four spades.  New spade size is 12" wide, 9" long. Taper starts at 3" from the aft edge.  Used 0.125" aluminum plate, cut on a bandsaw, then alodined and primered.  Area of the old is 36 square inches, new is 72 square inches.  
Here's the old and new spade compared:

  
First rigged and flight-tested the wings to fly level and matched incidence with no twist.  Had to add a couple of washers under the aft end of one of the I struts to keep a wing from dropping.  Wings look to be set for about 0 degrees incidence instead of the more usual 1.5 degrees.  Then installed one spade set to parallel the chord line and rechecked the trim in flight.  Shimmed the spade with washers until aircraft flew neutral roll trim again, then installed the second spade and shimmed it until the trim was same neutral as without the spades.

Checked the horizontal stabilizer and found it rigged to +1 degree instead of +2.  Still, elevator seems to fly in close to neutral trail so I'll leave it for now.  Especially after realizing that the bolts on the front tube would have to be lengthened, with all that would entail........

Elevator travel adjusted to 25 degree up and down (spec +/- 2 degree).  Ailerons the same at 25 degrees up and down (adjusted at the the stopbolts on the side of the stick).  Rudder is 30 degrees left and right.

  

 

 

2009

 
Re-fabric Wings - moved to its own section.

 
Stick Slop

Stick had some side to side play that I identified came from the two stub bushings welded onto the torque tube getting worn.  Maybe some industrial Loctite would have fixed it, but I did it the hard way:  removed the tube, drilled out the old bushing, welded in new ones, and repainted the torque tube red.  BTW, I've noticed a few other older Pitts, S-1 and S-2 with the same lateral play after a few years.

 
Honey, I Shrunk the Spades

Felt I was just a little over-spaded, so I trimmed 1/2" of the sides and front.  Area now 65 sq inches instead of 72.

 

 
Cabane Fairing

Picked up a fairing from Raven Aircraft.  Should have mounted it to the wing before reinstalling the wings, then done the trimming to fit the cabanes instead of doing all the trimming and fitting with the wing on the plane.  Reminds me of a banana hammock, don't ask me why.

Tailwheel Locking Lever Spring

Standard spring is made from .078 "music wire", commonly found in hobby shops.  I copied Raven Aircraft's double spring concept using .062 music wire instead.

 

Installed Slick Magnetos and Harness.

Replaced the old Bendix (last overhauled in 1990 - time flies) mags with new Champion/Slick 4370 RH and 4373 (impulse) LH.    Timed 25 degrees.  Firing order is 1-3-2-4.

Timing is simple - remove the wiring harness cap, line crank index up with 25 BTC on compression for #1 (remove the spark plug and put your thumb over the hole) stick the special pin in the top hole on the back of the mag for a Left Hand rotation timing.  Mag is now ready to fire #1 cyl.  Slide it onto the gears, nuts snug and hook up the buzzbox (tired of borrowing, I'm going to get one) to sync the mags.

 The wiring wasn't the same as the Bendix - the RH mag feeds the top 1-3 plugs not the bottom.  The wire lengths on the new harness didn't seem right when I put it in incorrectly the first time so after a quick call to Champion they told me that they had even labelled the sparkplug ends with T1 for top #1, B2 for bottom #2, etc.  Now even a pilot can figure it out.

The screws on  wiring harness caps can be turned with either a simple blade screwdriver or a T-20 torx bit.  Handy to know in tight quarters like an S1.

If you get the colored harness (I went with red, of course) you do not use the plastic clips in the little clamps that hold the harness wires.  I guess they are a larger diameter and the plastic grips them a little too tight.

The engine gear on the impluse mag came off easily enough, the other one was tight and I had to use a gear puller to break it free.  Split pins are a little work to get into the recessed castellated nut when you put the engine gears onto the Slick mags.
 
 
 
 
Next.........
Engine Cowling, the new Wolf one to match the gear, and probably make up a new firewall at the same time (Steve Wolf said "your old one is probably full of patched holes by now", how true)

 

Updated July 20, 2009