January - present, 2010

2010-07-12

• Company president, Jay Carter, will be giving a forum at this year's EAA Airventure in Oshkosh. The presentation will be on Saturday, July 31st from 11:30 AM - 12:45 PM in the Remos Aircraft Pavilion #11. (more info)
• Continued work on the 4-Place PAV Prototype.
  • Continued with the wiring & avionics.
  • Completed side load test on the 5 point pilot's harness.
  • Fabricated gas tank.
  • Completed test of the automatic mechanical pitch mechanism. We tested the full operating limits of pitch change and coning , and proof loads on the mechanism to 1.5 times the maximum load possible during prerotation.
  • Completed testing of the 15' blade. We cycled the rotor from 0 rpm to 900 rpm 256 times, which created a centrifugal force from the tip weights 1.5x higher than what will occur in the full size blade at 375 rpm. We then performed one cycle to 1175 rpm, which created a centrifugal force 2.56x higher that what will occur in the full size blade at 375 rpm.
  • Built the test stand that will be used to test the full size rotor. We will perform a proof test to 412 rpm before installing the rotor on the aircraft. We plan to perform the test this week.
  
  
  

  Rotor Head Installed in Rotor Completed Full Size Rotor in Test Pit

2010-06-03

• We apologize for the lack of an update in May. Once again, engineering has taken precedence over the website.
• We've signed an agreement with the Wichita Falls Economic Development Corporation (WFEDC) on a $4 million job incentive program. The agreement provides $4 million of operating capital in the form of a loan to Carter to facilitate increased development activity and corporate expansion. The 7 year no-interest loan provides for a delayed re-payment period to allow Carter to concentrate on creating a solid base for growth. There is also a forgiveness provision that is applied to the loan for new job creation by Carter's move into production and manufacturing. (more info)
• Received approval of another patent - Automatic mechanical control of rotor blade collective pitch
• Continued work on the 4-Place PAV Prototype.
  • Continued with the wiring & avionics, including programming of the data collection system.
  • Installed & completed a proof test on the 5 point pilot's harness.
  • Relocated prop & throttle to dash. Changed to Vernier type controls.
  • Ran the engine several times under Lycoming supervision to calibrate the alternators and prop governor along with an extended shaft torsional vibration survey and cooling test. We've sent the prop back to MT so that it can be modified to enable flat pitch (minimal hp) operation so maximum hp is available to overspeed the rotor during prerotation.
  • Built the rotor spar that will be used for flight testing. Completed a proof test to limit load.
  • Applied fire proof paint inside engine compartment.
  • Built the rotor spar that will be used for flight testing. Completed a proof test to limit load.
  • Built and assembled the full size rotor, along with all pitch control mechanism, that will be used in flight testing. We will perform a proof test to 412 rpm before installing the rotor on the aircraft, pending successful completion of the 15' blade test.
  • Built a new 15' blade to test the tip structure and rebuilt the test stand with appropriate modifications. We've already balanced the blade and will begin testing this week. We plan to perform a minimum of 250 cycles between 270 and 900 rpm, which will result in a centrifugal force from the tungsten weights 1.5 x higher than will occur in the full size blade at 375 rpm. The test pit has been modified for these tests. It was dug slightly deeper, the berms were squared off, and a larger concrete pad was poured in the base. A containment wall of 2' x 2' x 4' solid concrete blocks was built on the pad surrounding the rotor and test stand.
  • Tested another rotor skin to spar attachment specimen. We performed 16,000 cycles at 240,000 lbs, and 1 cycles at 360,000 lbs. For reference, these test loads are based on 140,600 lbs of centrifugal force from the rotor at 375 rpm (the max jump takeoff rpm for the present gyro rotor - note a next generation lighter rotor with the same 75# tip weight in each blade will have a centrifugal force of 140,000 lbs at its max jump takeoff rpm of 400).
  
  
  

  Engine Run Completed Blade for Full Size Rotor New Test Pit 15' Test Blade in Test Pit

2010-04-06

• We apologize for the lack of an update in March and the delay in this update. We have been extremely busy getting the PAV Prototype ready to fly.
• Continued work on the 4-Place PAV Prototype.
  • Continued with the wiring.
  • Completed the tilting mast test.
  • Completed proof test on the pilot seat.
  • Started the engine for the first time, confirming that all necessary systems were functioning properly.
  • Performed several 'dummy' layups of the new rotor tip design to develop the best procedure to build the tip. Based on that procedure, we built a 15' diameter test blade, and began construction of full size blades for the 45' diameter rotor. We tested the 15' blade to 900 rpm, which resulted in a centrifugal force from the tungsten weights 1.5x higher than will occur in the full size blade at 375 rpm. We had planned to perform 1000 cycles to this rpm, but the torque restraints on the test stand failed after 3 cycles. Without the torque restraints, the motor & blade assembly were free to wobble, and the resulting motion caused a failure of the bracket that held the test blade to the test stand. Once the blade was free, it impacted the test stand, causing irreparable damage to the blade. We will build a new 15' blade and test it after making appropriate modifications to the test stand. We will continue construction of the full size blade, but limit it to 325 rpm until we have completed and tested the new 15' blade.
  • Built a fourth test rotor spar. The design of the titanium plates was changed to eliminate the uni dogleg and let the titanium plates carry the load direction change. The spar was cycled 10,000 times going from 45,000 to 260,000 lbs, and then 1000 times going to 340,000 lbs. After the cycle testing was completed, the load was slowly increased until the spar failed at 412,500 lbs. For reference, these test loads are based on 160,000 lbs of centrifugal force from the rotor at 400 rpm (the max jump takeoff rpm). A spar of the same design is being built which will be the part flown on the aircraft.
  • Laid up another rotor skin test speciment. We are currently in the process of performing the cycle tests (using the same loading scenario as was done for the spar).
  
  
  

  Engine Bay Seat Proof Test Full Size Blade Skin 15' Test Blade New Spar Design

2010-02-04

• Continued work on the 4-Place PAV Prototype.
  • Continued with the wiring.
  • Completed the baffling & installed 2 cooling fans.
  • Completed a new tilting mast and test fixture. We began to test the mast, and had a slight failure of a shear web bond at a vertical lift of 6810 lbs and a side load of 1054 lbs at the top of the 55" long mast. We have repaired the bond, and plan to continue testing this week.
  • Installed a fire suppression system.
  • Installed the gascolator and fuel pump.
  • Performed a 'dummy' layup of the new rotor tip design. We discovered a few aspects of the design that could be improved, and will start a new 'dummy' layup this week. Pending a successful 'dummy' layup, we will start construction on a 16' diameter test blade, followed by full size blades for the 45' diameter rotor.
  • Continued testing the second test spar. The spar had previously been cycled 10,000 times going from 45,000 to 262,500 lbs. For the next test, we increased the load to 360,000 lbs. After several seconds at that load, the spar failed. The failure appears to have started at a dogleg in the unis that were supported with circumferential windings. We have started design on a fourth spar to eliminate the uni dogleg and let the titanium plates carry the load direction change. Note this is exactly the same load at which the first spar failed, however at that time we thought that failure occurred because of a circumferential windings failure. (Note the failure of the second spar occured after a third test spar had already been built - see below.)
  • Laid up a third spar to test. In contrast to the previous design, fillets were included in the mold itself, so that no extra pieces were required for the circumferential windings. Additionally, the titanium pieces in the spar were prepared for bonding by sanding, without any chemical treatment (the two previous spars had been chemically treated). This spar failed after 8,838 cycles going from 45,000 to 262,500 lbs. It appears that the lack of chemical surface treatment caused to the failure.
    
    For reference, these spar proof test loads are based on 160,000 lbs of centrifugal force from the rotor at 400 rpm (the max jump takeoff rpm).
    

2010-01-05

• We completed the second milestone under our contract with AAI, performing a critical design review for the 4-Place PAV Prototype. The review was a bit unconventional, considering that we've already begun construction of the aircraft, but it brought AAI up to speed on the design, and it was good for us to hear critiques from new people.
• Please excuse the lack of an update for December. We were tied up with a few very important projects.
• Continued work on the 4-Place PAV Prototype.
  • Continued with the wiring, including voltage regulators and the nav/comm antennas.
  • Continued work on the baffling system.
  • Completed a new tilting mast and performed a proof test. The mast failed in the steel fitting at the pivot point at a load of 34,300 lbs (this is still a good safety factor, but short of our intended proof test load). Upon inspection, the failure was due to a weld that didn't achieve full penetration. We have begun work on a new mast and redesigned the tooling to ensure a full penetration weld. We've also redesigned the mast test fixture so the mast can be tested in every possible load configuration.
  • Completed modifying the tip of the rotor blade mold. The new shape makes the transition more gradual from the constant chord section to the increased chord at the tip. We also laid up molds for a short 15' diameter blade to do a proof test of the rotor tip. This test blade will match the real blade in the tip, but will be a continuous structure from one side to the other in the inboard region. The blade will be spun at a high rpm that will produce a centrifugal force from the tungsten weight 3 times higher than possible from the actual 45' dia rotor at its maximum overspeed rpm of 400.
  • Laid up a second spar to test. In contrast to the previous spar, this spar was laid up mostly in a single operation, rather than in two halves that were bonded together. Additionally, resin/carbon inserts were installed to provide a radius for wrapping the circumferential windings.
    
    Multiple tests have been completed on this spar. In the first, load was applied in 25,000 lb increments up to 275,000 lbs, taking measurements from several strain gauges at each load. For the second test, the spar was cycled 10,000 times from no load to 238,000 lbs. The third test was a repeat of the first, to verify that the strain measurements were the same (i.e. no damage occured during the fatigue test). After the first test, and after 1,000, 5,000, and 10,000 cycles in the second test, ultrasonic inspections were performed to ensure that no delaminations had occured. We have shipped the spar to an outside company, where more involved fatigue testing will be conducted, followed by a test to failure.
    
    We have begun construction of a 3rd test spar. Fillets were added to the mold itself, so that no extra pieces will be required for the circumferential windings. This spar will also have a skin of 1 ply of 0-90, eliminating the need for the spiral windings that ran the length of the two previous spars.
    
    For reference, these spar proof test loads are based on 160k lbs of centrifugal force from the rotor at 400 rpm (the max jump takeoff rpm).
     
  • Completed proof testing of the new fixed horizontal stabilizer. For the first test, a symmetric load of 2200 lbs was applied. For the second test, a 200 lb load was applied at the outboard tip.
  • Completed proof testing of the engine support - 9 g's static down load and 960 ft lbs (436 hp at 2400 rpm).
  
  
  

  Engine Support Torque Test Setup Spar with Instrumentation New Tilting Mast Horizontal Stabilizer Symmetric Proof Test