January - present, 2008

2008-12-02

• Completed the rotor spar, including bonding the hub hardware adding the circumferential uni windings where the two caps come together.
• Performed an 8000 ft-lb proof load on the spar. This is twice the max operational torque.
• Completed the upper & lower skins for the second blade.
• Made the rotor blade shear web and rib plugs, and then made the high temperature molds from the plugs.
• Built a welded steel bracket to support the rotor gearbox.
• As described in a previous update, we've built a new bracket to hold the tilting mast which uses variable spring rate elastomerics. We've cut the old bracket out of the fuselage, and have begun preparing the fuselage to install the new bracket.
• Finished all the hardware for the rotor spindle and pitch mechanism
  
  

  Rotor Spar Proof Test Rotor Root Rib Tooling Rotor Head Components

2008-11-03

• Completed modifying the rotor spar molds per the new rotor design.
• Performed several test layups in the spar mold to determine the best method to lay-up the pre-preg material.
• Built the rotor spar.
• Completed the upper & lower skins for one blade.
• A Lycoming technician visited to modify the engine - changed the flywheel and added a second alternator, relocated the prop governor in anticipation of the turbos, changed out the fuel injector lines, and added an adaptor for a remote oil filter.
  
  

  Blade Lower Skin Rotor Spar

2008-10-13

• We apologize for the delay in posting this update. Our webmaster was busy with an important engineering project.
• Modified the rotor spar molds per the new rotor design.
• Layed up several test spans for the new rotor to determine the best techniques to use for pre-preg carbon. Layed up one of the skins, but the resin exothermed during the cure, ruining the part. We have discussed this with the pre-preg manufacturer, and have developed a new cure cycle to use on the next part that should fix this problem. We've also used this first layup to improve the design and construction process.
• Made a few modifications to the tail boom to increase the stiffness and completed proof testing to a load of 2275 lbs.
  
  

  Tail Boom Proof Test New Pre-Preg Rotor Blade Skin

2008-09-02

• Completed the new rotor blade molds. Because we are going to use pre-impregnated carbon (pre-preg) to build our new rotor as opposed to a wet layup, and because pre-preg requires a higher cure temperature, we needed molds made with a resin system capable of withstanding those higher temperatures.
• Tested the tilting mast elastomeric bearing support. The test involved mounting two fixed weights totaling 320 lbs at the top of the mast to simulate the overall mass of the rotor, and a smaller eccentric weight to simulate a rotor out of balance. The eccentric weight was spun over the range of rpms at which the rotor will operate. Because the elastomeric support is made with a variable spring rate, the natural frequency of the system changes as the elastomeric is compressed, so the system is never driven to a large amplitude oscillation. We also performed an extended test, spinning the eccentric weight for three hours to ensure that the system functioned properly without overheating or any unanticipated problems. The system worked, and at the end of the test, the elastomeric had not taken on any set from the repeated deformations.
• Proof tested the horizontal stabilizer. We applied 1300 lbs to each side of the stabilizer (2600 lbs total). The part performed as designed.
• Tested the tail boom by applying a load on the horizontal stabilizer. Before reaching the intended load, the test was stopped because the deflections were too high and the skins were starting to buckle in certain areas. The tail boom will be stiffened in those necessary areas, and the test repeated once those changes have been made.
  
  

  Horizontal Stabilizer Proof Test New Pre-Preg Rotor Molds Elasto Support Test

2008-08-04

• Company president, Jay Carter, will be giving a presentation on Carter's technology and an Update on the new PAV at this year's Popular Rotorcraft Association Convention in Mentone, Indiana, scheduled for Saturday, August 9th, at 10:00 am. (more info - PDF Flyer for the Event)
• We released five press releases during our press conference at Oshkosh. These releases discuss the progress of our new 4-Place PAV prototype, the projected performance of the aircraft, the several companies we are working with on the aircraft, new additions to the Carter team, and show a few pictures. To read them, visit our Press Release section.
• Completed the proof test on the composite mast. We put a 29,000 lb load on each of the mast support bearings for a total vertical equivalent lift of 58,000 lb, and kept the load applied for several minutes (pretty good safety factor for a 3500 lb aircraft). To put this load into perspective, during a jump takeoff at the max rotor rpm of 400 with the rotor making as much lift as is possible, if the pilot tilted the rotor as far to the back and side as possible, with the mast tilted as far forward as possible (which in reality is very unlikely to happen), then the moment generated on the mast at one of its attachment point would still only produce a load two-thirds of that to which we tested. Our next major structural tests will be the horizontal stabilizer, the tail boom and the new elastomeric bearing support in the aircraft strong back.
• We are going to use pre-impregnated carbon (pre-preg) to build our new rotor, as opposed to a wet layup. Because pre-preg requires a higher cure temperature, we have to build new rotor blade molds with a different resin system capable of withstanding those higher temperatures. We've already built a new plug of the rotor from the old molds, and are getting started laying up the new molds. We've also re-organized our shop, with one building dedicated solely to composites work, and another building for mechanical work and assembly. We installed air conditioning in the composites building to control the environment.
  
  

  Mast Proof Test with Tilt Cylinder New Rotor Plug in Old Mold

2008-07-08

• Update 2008-07-10 Company president, Jay Carter, will be giving a forum at this year's EAA Oshkosh Airventure. The forum, titled Carter's PAV Progress and The Future, is scheduled for 11:30 am, Saturday August 2nd, in Pavillion 11, the Remos Aircraft Pavillion (more info).
• While testing the rotor for our new 4-Place PAV prototype in the test pit, the rotor failed. Prior to that, we experienced problems when the test stand went through several natural frequencies, causing the rotor head at the top of the tilting mast to oscillate - in some cases violently as we tried to accelerate through a natural frequency. After several modifications to the test stand, the most important being an elastomeric mast pivot bearing with a good compromise of spring rate and dampening qualities, we were able to get through these natural frequencies and run the rotor at 250 rpm, where we could now use a harmonic balancer to more accurately balance the blades. With the aid of the harmonic balancer, we balanced the rotor nearly perfectly, such that the resonance at the natural frequencies was very small, and there was no visible vibration at higher rpms.
  
  After balancing, we ran the rotor to higher rpms for proof testing. Per our normal procedure, we increased in 25 rpm increments, studying the data and inspecting the rotor in between runs. At 420 rpm (Mach .89 at the tip), the rotor failed (the rate at which the rotor was accelerating at that point indicates we should have been able to achieve 440 rpm, and maybe our goal of 450 rpm - Mach .95 at the tip - with the given horsepower). After looking over the pieces of the rotor, studying the video of the failure, and double checking all of our analysis, we believe that the trailing edges of both blades initially failed or were significantly damaged in compression when the rotor head oscillated violently as described above. This damage occurred near blade station 114 where the spar first attaches to the blade, because with almost 50% of the entire blade weight located in the outboard 20% of the blade, the edgewise moments on the blade caused by the oscillation became much greater than what the blade was designed to handle. Unfortunately we did not see it during our inspections - probably because we did not expect a problem in this area and did not inspect it closely. As the rotor was spun at higher rpms, due to the higher aerodynamic loads as the blade tip entered the transonic regime, and the higher centrifugal loads, especially on the 55 lb lead weight located near the blade tip ahead of the leading edge, a high compression load failed the blade trailing edge. Once this occured, all the bending moments had to be carried by the narrow spar. The spar is very strong in tension with a 4 times safety factor at our proof load, but it will not carry a high edgewise bending load and as a result failed.
   
• We plan to build the next rotor out of pre-impregnated carbon (pre-preg), as opposed to the wet layup that was used for this last rotor. While wet layups have advantages for this type of prototyping work, pre-preg can be purchased with superior resins - the material is stronger, has a much higher heat index (ability to take higher temperature such as one would encounter in the desert), and the fabrication consistency is much better.
• A technician from Lycoming came out to set up the IO-540 engine for our application - remote oil filter and cooler, twin alternators, adapters for prop governor, relocated fuel injector lines and intake manifold.
• Mass balanced the horizontal stabilizer and outboard vertical stabilizers. It's now complete except for painting.
• Continued work on the new composite tilting mast.
  
  

  Rotor in Test Pit

2008-06-03

• Continued testing the rotor for our new 4-Place PAV prototype in the test pit. We've had to re-design the gearbox housing and have a new one built. The bolt flanges on the original design weren't strong enough to handle the gear "spit" load. The new housing has been installed on the test stand and we are ready to resume testing.
• Fabricated the engine mount for the Lycoming IO-540 engine, and mounted the engine in the aircraft.
• Continued work on the horizontal stabilizer. We bonded both of the outboard vertical stabilizers to the horizontal stabilizer.
• Continued work on the new composite tilting mast.
• Bonded on co-pilot half of the upper cover of the tail boom.
  
  

  Horizontal Stab with Outboard Vertical Stabs Engine Installed with Engine Mount

2008-05-05

• Update 2008-05-15 A new 60 Minutes on Yahoo segment titled "Flying Cars" is now online. It is based on the "60 Minutes: Highway in the Sky" segment that originally aired in 2005. It will be featured as the main story on their homepage until Sunday evening, and is also available directly at Flying Cars on 60 Minutes.
• Began testing the rotor for our new 4-Place PAV prototype in the test pit. As per our usual conservative approach, we will perform many test runs on the rotor, incrementally increasing the rpm. Thus far, we have reached 250 rpm, with a planned maximum of 450 rpm (.95 Mach tip speed). During flight testing, we will limit the rotor to a maximum of 400 rpm, which will only occur for max performance jump takeoffs. The automatic mechanical collective and jump takeoff rotor pitch control appears to be working well. We are making a slight adjustment to the spring rate, and will continue testing this week.
• We are working with Greg Richter (founder & CEO of Blue Mountain Avionics) to develop our avionics, data collection system, video, auto pilot, electronics, and controls for the tilting mast, rotor rpm, wing angle of attack, and for optimizing propeller efficiency. He visited our facility this month to see the aircraft and kick off the project.
• Received the actual Lycoming IO-540 that will be used in the aircraft (as opposed to the non-functioning version we previously used for layout purposes), and have begun making the engine mount.
• Continued work on the horizontal stabilizer. Per advice from Greg Richter, we mounted antennas inside the horizontal stabilizer, and then bonded the skins together. Performed the prefinish on the outboard vertical stabilizers that will be bonded to the horizontal stabilizer.
• Bonded carbon reinforcement to the strongback around the bracket that will hold the rotor mast.
• Installed a conduit down the length of the tail boom for running wire.
• Installed the wing root fairing & began prefinishing the underside of the fuselage.
  
  

  Rotor in Test Pit Lycoming IO-540 Engine Horizontal Stab & Tail Boom Outboard Vertical Stabilizer

2008-04-07

• Update 2008-04-08 Jay Carter will be giving a presentation at this year's Sun 'n Fun Fly-In, titled "Carter's New Personal Air Vehicle And The Future." His forum will be at 12 noon on Friday, Aprill 11th, in Tent 11 (not 7, as previously stated).
• Polished the windshield & installed it in the canopy of our 4-Place PAV prototype.
• Test fitted the Lycoming IO-540 in the engine compartment. We made a slight modification to the firewall to provide more clearance. We are currently working with Lycoming on an exhaust to fit in the engine compartment.
• Installed the 4-bladed MT propeller onto the drive shaft, test fitted it on the aircraft, and trimmed the fuselage accordingly. To allow us to fly sooner, we will initially use this commercially available propeller. Once flight testing has begun, we will begin development of a Carter scimitar propeller.
• Continued work on the horizontal stabilizer. We have completed all the composite parts, and pre-bonded the internal ribs and shear webs to the skins. We are waiting for experts from Blue Mountain Avionics to visit this week, where among other things they will help locate the antennas inside the horizontal stabilizer before we bond the skins together.
• Completed the canopy latching mechanism.
• Tested the cyclic link fittings & made changes to the design per the test.
• Modified the instrument panel to provide more leg clearance.
• Completed installing all electrical components in the rotor head, including sensors and the solenoid to engage the automatic mechanical collective. Finished work on the electronic data collection system in preparation for testing the rotor on the test stand.
  
  

  Jay Carter in the PAV Engine Test Fit in PAV PAV with Canopy Open PAV with 4 People PAV with Prop, Engine Cowling & Panels Horizontal Stabilizer Ribs & Shear Webs Calibrating Electronics at the the Rotor Calibrating Electronics at the Collection System

2008-03-03

• We received a non-functioning version of the engine that will go in the first 4-Place PAV prototype, to use for fitting purposes. It is a Lycoming IO-540. We are currently working with Lycoming to make a few modifications to the exhaust so that the engine will better fit in our engine compartment.
• Received our windshield from the manufacturer. Unfortunately, the windshield didn't follow the proper contour, and wouldn't fit properly into the canopy. We had to heat and vacuum form the acrylic ourselves to get the correct shape. We are currently polishing the windshield, and will then install it in the canopy.
• Received a 4-bladed prop from MT propeller. To save development time for the first prototype, we will initially use this commercially available propeller. Once we have completed all the work necessary to begin flight testing the aircraft, we will begin development of a Carter scimitar propeller. Having both propellers will provide a very good apples to apples comparison of the performance of a Carter prop to a more conventional design.
• Began work on the horizontal stabilizer. We laid up the skins, made all the tooling for the internal ribs and shear webs, and have begun laying up those internal parts.
• Built and installed the hydraulic master cylinder assembly that will pressurize the prerotator and rotor brake.
• Began work on the canopy latch.
• Continued installing the electrical components in the rotor head, including sensors and the solenoid to engage the automatic mechanical collective. We also began work on the electronic data collection system to input the data from those sensors in preparation for testing on the test stand.
  
  

  Canopy Latch Paritally Completed Horizontal Stabilizer Skins MT Prop & Spinner, Still in Packaging Lycoming IO-540 (non-functional, for fitting, only)

2008-02-04

• Performed a static test on the composite tilting mast for our 4-Place prototype. This test was performed not just on the mast itself, but also the air over hydraulic cylinder that will control it, and the mounting hardware. A steel pivot fitting in the mast failed at a load greater than what is possible in flight, but less than our design proof load. Subsequent analysis revealed an unanticipated bending moment on the fitting, due to the pivot pin not being sufficiently rigid. The pivot pin has been redesigned. While we are rebuilding the mast, we are beefing up the structure to give it an even greater safety factor.
• Changed the canopy from a sliding mechanism to a tilting mechanism, which is simpler and more reliable.
• Completed installing cables & pulleys for the rudder and horizontal stabilator control.
• Completed and installed the upper linkages for the cyclic control.
• Created a pull test fixture and began making test specimens to verify the bond strength of a new resin system.
• Began installing the electrical components in the rotor head, including sensors and the solenoid to engage the automatic mechanical collective.
  
  

  Tilting Mast Static Test PAV with Closed Canopy PAV with Open Canopy

2008-01-07

• Performed an 18,000 lb static test on the rotor head & made a few changes to the design based on that test.
• Began installing cables & pulleys for the rudder and horizontal stabilator control.
• Completed the mold for the instrument panel & laid up the part. Test fit panel in the aircraft.
• Built the plug & mold for the outboard vertical stabilizers, then laid up & bonded the actual parts.
• We've decided to change the canopy from a sliding mechanism to a tilting mechanism. This will be simpler and more reliable. We're nearly completed machining the parts for the hinge, and will begin modifying the canopy and fuselage shortly.
• Built a false floor to go above the wing & below the rear seat. Modified the installation of the rear seat for increased headroom & leg room.
  
  

  Rotor Head Static Test Instrument Panel Outboard Vertical Stabilizer