October - December, 2005

2005-12-27

• Installed the propeller designed for the 66 HP Rotax 582 engine onto the modified Butterfly autogyro, along with the pitch change mechanism. We plan to begin testing the system this week.
• Continued construction of the 26' rotor to be used on the modified Monarch autogyro. Completed all of the parts for the second blade, and began the assembly of that blade.

2005-12-19

• Completed proof testing of the propeller designed for the 66 HP Rotax 582 engine. We ran the prop for a total of 7 minutes (four 15 second runs, four 30 sec runs, and four 1 min runs) at 3000, 3200, 3400, 3600, and 3800 rpm, with a few 1.5 second averages at 3890 rpm (tip speed Mach .915). Because we were operating at cruise pitch, the air flowing over the upper surface was accelerated to over Mach 1 and it took 273 HP to spin the prop at 3800 rpm. The maximum rpm the prop should ever see in normal Butterfly operation is 2650, which would occur at full throttle in a 100 mph dive.

  Inspecting the Rotax 582 Prop on the Test Stand

• Continued construction of the 26' rotor to be used on the modified Monarch autogyro. Completed the layup of one blade.

2005-12-12

• Tested the propeller designed for the 66 HP Rotax 582 engine installed on the modified Monarch autogyro. The Carter propeller produced 16% more thrust than the wooden prop originally installed on the aircraft, at 93% of the horsepower, while operating at lower noise levels.

  Rotax 582 Prop- Thrust Test

  The designer of the Monarch, Larry Neal, has done a good deal of testing to find the optimum propeller for use with this engine. The best propeller he found, a wooden propeller, produced the same static thrust as a 3 bladed ground adjustable composite prop and 20 pounds more static thrust than another 2 bladed wooden prop.
  
  We tested the wooden prop and the Carter prop on the Monarch, swapping out one propeller for the other as quickly as possible so that temperature and other conditions would be as close as possible. The temperature on the day of our testing was around 60º F. The wooden propeller produced 280 pounds of thrust at 6200 engine rpm (62 hp), while the Carter propeller produced 325 pounds of thrust at 5882 engine rpm (59.6 hp). We did not get quite as good of performance as we were predicting for our propeller, most likely due mainly to the fact that there is no streamlining of the aircraft, and the root of the prop blade is not seeing "clean" airflow.
  
  Changing the gearbox ratio would allow the Carter propeller to spin at the engine's peak HP rpm at zero airspeed, improving static thrust, but then as the airspeed increased, the engine rpm would run too high. The current setup is a good compromise between low speed and cruise flight, so that the pilot should be able to fly at full throttle at any airspeed the aircraft is capable of without overspeeding the engine (with the wood prop installed on the Monarch, the pilot must throttle back at cruise to keep from overspeeding the engine).
  
  The noise levels of the Carter prop also compared favorably to the wooden prop, which itself was just as good as any other prop that Larry Neal tested. As measured by Carter using a decibel meter at a distance of about 50 ft, the noise levels of the wooden prop were 95 dB at the rear, 91 dB at the side and 90 dB at the front, while those for the Carter prop were 92 dB at the rear, 89 dB at the side and 90 dB at the front. We plan on performing more noise tests with an additional muffler installed on the aircraft (it already has one main muffler and one smaller muffler) in order to reduce the influence of the engine noise on the decibel measurements.
   
• Continued construction of the 26' rotor to be used on the modified Monarch autogyro. Continued laying up the internal components and test fitting components for the main layup.

2005-12-05

• Continued work on the propeller designed for the 66 HP Rotax 582 engine. We completed modifications to the propeller and tested it to 3400 rpm. No problems were found during the testing. We have decided to postpone the testing to 3800 rpm, in order do some limited performance testing with the propeller installed on the modified Monarch autogyro. The proof test to 3400 rpm still provides a reasonable safety factor, since the prop should only see a maximum of 2615 rpm in operation. Once the limited performance testing has been completed, we will continue proof testing the propeller to 3800 rpm.

  Rotax 582 Prop on Test STand

• Began making a few small modifications to the modified Monarch autogyro to provide sufficient clearance for the Carter prop.
• Continued construction of the 26' rotor to be used on the modified Monarch autogyro. Continued laying up the internal components and began testing fitting components for them main layup.

2005-11-28

• Continued work on modifying the propeller designed for the 66 HP Rotax 582 engine. We tested the pitch change mechanism independent of the propeller. While running at a proof load of four times the operational load, one of the rod ends failed. Examination of the other three rod ends after the failure, which all experienced the same loading as the failed rod end, indicates that the failed part was defective. It failed at roughly 3/4 of its rated load.
• Continued construction of the 26' rotor to be used on the modified Monarch autogyro. Continued laying up the internal components and the main spar. Received the machined rotor head and test fit it on the spar.

  Test Fitting Rotor Head onto the Spar

• Performed a test on the Butterfly to ensure that there are no natural frequencies in the drive train that are excited by the engine (i.e. that the first natural frequency of the drive train is higher than the engine rpm). All drive train parts were installed on the aircraft as they will be in flight. The engine was run up to its full rpm, and no harmonic problems were discovered.

2005-11-21

• Had the engine for the propeller test stand rebuilt and resumed testing of the propeller designed for the 66 HP Rotax 582 engine. We reached 3000 rpm before noticing a slight failure developing at the prop pivot bearing. (We plan to take the propeller up to 3800 rpm as a proof; it was designed for a max of 2615 rpm in operation.) The problem was discovered before a catastrophic failure occurred, so we will be able to modify the propeller and continue testing. We are working on the modification.

  Inspecting the Rotax 582 Prop on the Test Stand

• Continued construction of the 26' rotor to be used on the modified Monarch autogyro. Completed laying up the skins. Began laying up the internal components and the main spar.

2005-11-14

• A slight out of balance showed up during propeller testing, so we spent the first part of the week rebalancing the propeller and ensuring that the test stand was balanced and running true. Once the test stand was back together, we tested the propeller up to an rpm of 2750 before one of the main bearings on the engine spun. We will continue testing once the engine is rebuilt. We plan to take the propeller up to 3800 rpm as a proof; it was designed for a max of 2615 rpm in operation.

  Inspecting the Rotax 582 Prop on the Test Stand

• Continued construction of the 26' rotor to be used on the modified Monarch autogyro. Completed all tooling for the internal components. Began laying up the skins.

2005-11-07

• Completed the new propeller designed for the 66 HP Rotax 582 engine, to replace the prop that was damaged when the test rig failed. We have begun testing of the prop on the test stand.

  Rotax 582 Prop on Test Stand

• Continued construction of the 26' rotor to be used on the modified Monarch autogyro. Continued making tooling for the internal components.

2005-10-31

• Continued building a new propeller designed for the 66 HP Rotax 582 engine, to replace the prop that was damaged when the test rig failed. All components have been laid up and cured, and we are in the process of putting them all together. One blade has been completed.

  Partially Completed Prop for Rotax 582

• Continued construction of the 26' rotor to be used on the modified Monarch autogyro. Continued making tooling for the internal components. The root rib, which is the most critical to ensure that the root fairing lines up when the blade is assembled, has been completed. Made the molds for the lead weights that will go in the tip of each blade.

2005-10-24

• Continued building a new propeller designed for the 66 HP Rotax 582 engine, to replace the one that was damaged when the test rig failed. The spar has been laid up and cured, and should be completed this week. The new skins have been completed. The drive shaft was removed from the test stand in preparation for modification.
• Continued construction of the 26' rotor to be used on the modified Monarch autogyro. Continued making tooling for the internal components.
• Continued work on the modified Monarch autogyro. Performed taxi tests with the new nose gear. With no pressure on the rudder pedals, the nose gear would shimmy, but as soon as pressure was applied to the pedals, the shimmy would go away. The nose gear rigging has been modified to correct this problem.

2005-10-17

• Began testing the prop designed for the 66 HP Rotax 582 engine. The prop did not fail, but the prop extension required to provide prop / test stand clearance failed. This was due to the fact that although the prop was balanced, the extension did not run true, which caused an out of balance that caused the bolts to break. When the bolts broke, the prop actually came off the end of the drive shaft in one piece before one of the metal parts hit and destroyed the prop. We have begun building a new propeller, and will modify the extension before testing again.

  Rotax 582 Prop on Test Stand

• Continued construction of the 26' rotor to be used on the modified Monarch autogyro. Continued making tooling for the internal components.
• Continued work on the modified Monarch autogyro. Began building a new gas tank/seat with a greater fuel capacity than the original.

  Partially Completed Gas Tank/ Seat

2005-10-10

• Completed the prop designed for the 66 HP Rotax 582 engine. Began building a special fixture for the test stand to test just the pitch change mechanism of the propeller independent of the rest of the prop.

  Rotax 582 Prop on Test Stand

• Continued construction of the 26' rotor to be used on the modified Monarch autogyro. Continued making tooling for the internal components.
• Put a new nose gear on the modified Monarch autogyro. To save design time and cost, an an off the shelf mountain bike front strut was modified for use on the aircraft. In the future, the fork could be modified further to accept a Carter Smart Strut.

  New Ultralight Nose Gear