- Feb 18, 2011
- Reaction score
Aircraft was designed and fabricated by Aircraft Restoration & Repair, LLC (AR&R) based on data from the Pitts S1S, S1T, S1-11B, S2B, Model 12, Weeks Solution, Rhin's Phoenix, Ultimate Aircraft, and special engineering by Clark (A & P, Mech Eng) and McGuire (Aero Eng). Clark provided Auto Cad drawings for this development. This airframe is #3 of the three built. A forth and fifth one are now being built.Welding was by Oxy/Acetylene with the exception of the cabanes and tail group, which was TIG Welded. Entire structure is fabricated from aircraft grade 4130. This airframe differs from #1 and #2 by overall length, upper longerons, gear type, and tail group. This fuselage has been increased by 4.00" for an overall frame length of 131.5". The upper longerons are of the same diameter from firewall to tail-post. The internal flight control system was fabricated from Clark Cad drawings and is very similar to the Pitts S1, except the control box is located above the longerons. Total stagger of upper and lower wings is 9.75 inches. Total wing cord is 45.75 inches. Seat slings are fabricated from rubber impregnated vinyl canvas. Slings are removable for maintenance. All fuselage sheet metal from firewall to cockpit is fabricated from 6061-T6 .025 Non-Alclad Alum sheet. Mini nut plates (# 6 & #8) have been riveted in place to facilitate ease of maintenance. Installed custom fabricated 5 Point Ratchet Hooker Harness. Harness utilizes two separate hard points on each side. Shoulder Harness is looped over the top of the roll-over structure. Wing panels were fabricated per Pitts drawings using airfoil NACA 63A015 for the upper wing and NACA 0012 for the lower wing. Utilized T-88 two part epoxy glue for all wood glue joints. Test blocks were created for upper wing center section and tested to failure. Unique modifications per Aircraft Restoration & Repair, LLC include extending wing panels 10" per each wing panel for a total of 19' 3 " foot wing span and total wing area of 108.63 sq ft. Utilized one additional set of S1S Drag Anti drag wires in outer bay. All spars are fabricated out of Douglas Fir of full depth and 1" thickness. Ribs are truss design similar to Pitts S1S/T. Ribs are made up of three separate parts, nose, center and trailing. All wing ribs are free of nails. Ribs were built using pressure plate jigs. Jigs were created using CAD layout drawings based on original factory S1S drawings. Ribs are secured to spars using corner blocking and the leading and trailing edge plywood also recaptures the rib. Leading edges were formed with two layers of 1/32 birch plywood utilizing a male/female forming jig.Stringers were installed between all nose ribs to avoid scalloping. Aileron span was increased to 83" for each panel. Aileron cove area is covered with one layer of 1/32. Three sets of aileron hinges are provided for torsional strength and rigidity. All internal wing hardware was purchased from Steen Aero Lab, S1SS type. All hinge support crush plates contain riv-nuts in lieu of AN nuts. Hinges and support brackets can be tightened externally without cutting fabric access. Upper wing contains a stock Pitts 4 gal tank, plumbed for fuel only. Trailing edge of wing is fabricated from .012 aluminum with 3/8" blunt edge for airflow re-attach. Aileron design is of the 29.9% hinge line symmetrical type.Aileron main spars (3/8" x 1 1/2") are fabricated from aircraft grade spruce. The front false sparis also fabricated from aircraft grade spruce. Leading edge is fabricated out of one layer of 1/32 90 degree Birch plywood. Leading edge plywood also captures rib. Aileron hinge blocks were C & C machined from Clark Cad drawings by Alco Services. Trailing edge of ailerons is fabricated from .012 aluminum with 3/8" blunt edge for airflow re-attach. All hinge support crush plates contain riv-nuts in lieu of AN nuts. Hinges and support brackets can be tightened externally without cutting fabric access. Fabricated bungee type landing gear using Pitts drawings as guidance. Overall height has been increased to account for larger diameter prop. Landing gear height has been set at 37.0 inches above the ground measuring from the front side of the forward landing gear fitting at the two point attitude. Landing gear center is located 5.0 inches forward of front face of Firewall. Landing gear forward sweep is set at 30 degrees. Landing gear wheel span is set at 63 inches to the inside of tires. Three-point angle of attack (AOA) Gear angle has been established at 12.5 degrees. Installed 5:00 x 5 Cleveland wheels and brake assemblies per Pitts drawings. Aircraft equipped with lightweight Sky-Tec 12 Volt 122-NL starter with the modified S-terminal, APU adapter plug, and 12 AeroVoltz Lith Battery. Starter does not require a separate Starter Solenoid. Battery, Battery Solenoid, Battery Master switch, and removable battery tray is located behind the pilot seat. Access is through the removal of seat sling. Aircraft not equipped with electrical charging system. Starter ring gear alternator drive groove has been machined off to reduce weight. Ring gear has been dynamically balanced. Aircraft is equipped with a Magneto switch and Push Button Starter switch located on left side of instrument panel. Installed VHF Advanced Aircraft Electronics High Gain Antenna System 5T within the lower right wing leading edge. Inst panel is fabricated out of 1/8" Honeycomb carbon fiber. Instrument panel can be removed easily due to six blind fasteners on the backside.Fuel system design is very similar to the S1S/S1T. Aircraft equipped with a Christian Manual wobble pump and valve assembly. Upper wing tank contains a stock Pitts Aux tank and is plumbed directly to the wobble pump. The 26 Gallon Main tank was fabricated by Acro Specialties per Aircraft Restoration & Repair, LLC prepared cad drawings and specifications for fabrication. A full depth standard flop tube (no O-Ring installed) assembly is installed. No smoke system components exist. A fuel sight system has been installed and calibrated for both two and three point attitudes. A Bendix RSA-5 Fuel Injection Servo and Distributor have been overhauled by Air Flow Performance and flowed for 300+ HP.