The FAA imposes Phase I and Phase II Operating Limitations on all Experimental Amateur-Built aircraft. During Phase I flight testing, new aircraft must be flown for 40 hours to demonstrate that the aircraft is controllable throughout its normal range of speeds and throughout all maneuvers to be executed, has no hazardous operating characteristics or design features, and is safe for operation.
If you are another JetExec builder you might appreciate a little advance reading of the work involved and the experiences I encountered, so I am logging my 40 hour adventure below. Hope it helps some.
| 2/26/14 |
First attempt to start turbine in over 6 years. Boost fuel pressure was good at 5 psi. Starter engaged, start fuel ignited, but main fuel did not seem to light. No indication of either main fuel pressure (P) or Exhaust Gas Temperature (EGT) on gauges. Terminated start. |
Troubleshot EGT and main fuel. EGT thermocouple (TC) wires were reversed. Swapped TC wires in port J-box; TC and EGT gauge responded O.K. to hot air gun.
Pulled 6 main fuel injectors out of turbine. Disabled turbine igniter (removed Cannon connector) and began second start sequence. Starter, start fuel O.K., still no significant main fuel P or flow out of the 6 injector nozzles. Terminated start. Noticed higher flows as fuel purged out of the 6 injectors. All 6 injector nozzles seemed to flow O.K.
Removed start fuel nozzle and main fuel manifold and injectors from turbine. Cleaned the final screen filter inside the main fuel manifold and used a syringe and lighter fluid to back-flush all 6 injector nozzles and lines. Tested/flushed the start fuel nozzle with syringe and lighter fluid and it atomized perfectly. |
Capped/plugged start fuel and main fuel lines, then turned on boost fuel pump and engaged starter. Boost fuel P gauge = 5 psi, main fuel P gauge = 200 psi.
Reinstalled all fuel injectors and lines and tightened all connectors.
| 3/4/14 |
Disassembled upper half of turbine fuel flow controller. Cleaned, lubed, verified that moving parts functioned smoothly, and reassembled. |
Began third turbine start. Main fuel P ~50 psi, main fuel ignited, EGT ~300F. Rotor began to turn, terminated start sequence.
Verified that throttle was off (idle). Let cool for 5 minutes. Attempted 4th start to monitor turbine RPM on tachometer. Starter would not initiate. Found blown 10A starter fuse in starboard J-box. Starter solenoid, turbine exciter, start fuel solenoid and governor must exceed 10A during start. Upgraded starter fuse to 15A, wires were already 14AWG.
Initated 4th turbine start. At throttle idle, although turbine fuel P and EGT seem low, turbine RPM reached 60-65% and KISS centrifugal clutch engaged as it should. Terminated start.
| 3/5/14 |
Worked on turbine fuel flow control unit (FCU). Engraved and marked a notch @ 12:00 o'clock position on the end of the fuel control lever 5/64" idle stop set screw. Backed the idle stop set screw out 1/2 turn to decrease the turbine's bottom idle speed.
Tightened the FCU torque motor lever return spring slightly. Noticed slight slop (0.010" ~ 0.015") in torque lever swivel link assembly rod ends that may contribute to governor "hunting" problems. Can add light spring across linkage in future if a problem.
Verified governor (M-GOV and A-GOV) circuits were both good. Measured throttle potentiometer resistances (with wires disconnected from the governor) as G to J = 4,970 ohms; G to K-L at throttle Idle = 1,584 ohms; G to K-L at throttle Full = 2.2 ohms. Throttle to governor wiring was O.K.!
| 3/7/14 |
Shortened FCU torque lever swivel link ass'y 1 full turn to ensure that I can back out the minimum fuel stop set screw further if needed.
John C. and my brother Todd came out to help. Made three attempts at turbine start. All three times the turbine ramped to over 60% and the centrifugal clutch engaged. The FCU torque motor would oscillate very rapidly (3-5 Hz) and then slam wide open to full fuel. On the last start attempt, switched from Starter to M-GOV position and the turbine began "barking" loudly, probably matching the torque motor oscillations.
Quit for the day and opened Kettner's bottle of scotch.
| 3/10/14 |
Removed the main rotor blades from the helicopter like I should have before attempting all the above. RTFM. Read The, um, Manual.
Cleaned and sealed top of upper M/R shaft bearing with blue gasket silicone RTV to seal and keep bearing from spinning on shaft.
My brother Todd and his son Conor came out to help. Reviewed and followed the KISS JetExec Start-Up and Run-Up procedure (for the most part). Disconnected governor output cable connector from the turbine fuel control torque motor, so that only the turbine mechanical idle stop set screw and the fuel control lever controlled the turbine speed.
Engaged the starter, the turbine spooled up to 55% ~ 60% and the KISS centrifugal clutch (C-clutch) engaged, immediately spinning up the M/R shaft (without the blades) and the T/R to match turbine RPM. Disengaged the starter, then the turbine idle speed slowly decreased continually to well-below 50%, where the turbine was no longer self-sustaining. Stopped fuel to the turbine. Adjusted the turbine idle stop set screw back in 1/2 turn to its original (3/5/14) position.
The second turbine start again spooled up to 55% ~ 60%, disengaged the starter and the turbine idle speed still slowly decreased continually. Stopped the turbine and increased the idle stop set screw another 1/4 turn.
Third, fourth starts, adjusted the idle stop set screw around the 3:00 o-clock position to where the turbine would sustain idle at ~54% RPM without engaging the KISS C-clutch.
Reduced the GAC Governor original Gain and Stability settings from 40% down to 30% each. Backed off the original Speed potentiometer setting 1 full turn.
With the turbine idling on the mechanical stop at 54% RPM, collective throttle at idle, reconnected the GAC governor output connector to the fuel control torque motor. No problems, but the torque lever did twitch off of idle periodically (every 1 second or so), without causing any significant/apparent speed increase.
Slowly increased throttle through 62% ~ 65% C-clutch engagement and then on up to the full throttle detent. Turbine and rotor were ~85% RPM. Slowly increased GAC governor speed potentiometer until turbine and rotor RPM both indicated 100%. The Rotax C gearbox vent filter was leaking oil, which Todd controlled with lots of paper towels for the next 10-15 minutes while the turbine was running.
Played with the GAC governor gain and stability settings without significantly affecting turbine operation. Finally left both settings back at original 40% setting.
Chopped the throttle several times to 85% ~ 90% and the turbine RPM decreased smoothly. Increased throttle at various rates back to 100% and the governor and turbine responded properly.
Turned alternator switch on for first time. The main battery ammeter indicated charging at 20A without any electrical, governor or turbine RPM problems observed.
Continued to run at 100% for ~10 minutes, observing all mechanical systems and gauges, while Todd continued to soak up oil flowing from the Rotax C vent. At 100% RPM, with no main rotor load, recorded the following readings.
Also inspected the T/R drive shaft, flex rings and u-joints carefully since the first turbine start and C-clutch engagement rapidly accelerated the rotor system. Everything looked good.
| 3/17/14 |
|Drained T/R gearbox oil. Cleaned gearbox and inside tailboom. Cleaned and inspected chip detector, removed black micro-dust. Modified vent pickup tube by adding small hole to try to prevent oil from pressurizing up inside vent filter. Refilled gearbox oil and attached vent.|
Modified Rotax C gearbox (C box) oil return line fitting to try to reduce vent filter oil leakage.
Started turbine. GAC governor still wants to idle at ~65% RPM. Called Todd C., Todd said to increase collective throttle potentiometer idle resistance (G to K-L at throttle Idle) to more than 1,600 ohms.
Did check turbine dual speed sensor voltage input to governor during turbine start. AC V input to governor must be >0.5V to register properly. After engaging starter, speed sensor input to governor was ~1.5V at ~1 second and ~ 3.0V at ~2 seconds into start cycle. Good!
Also did add spring to tension fuel control torque motor arm and fuel flow control lever arm together (light spring end-to-end across swivel linkage).
Still some oil leakage from C box and T/R vent filters. Chip detector lights on both as well. Need to fix all.
| 3/24/14 |
|Eliminated T/R gearbox top vent filter and replaced with new side pickup/overflow/drain tube.|
Removed bottom tub from helicopter to access collective throttle potentiometer. Adjusted throttle idle stop for 1,700 ohms input to governor at lowest idle. Throttle Idle detent still at 1,600 ohms, Full throttle still at 0 (2.2) ohms to governor.
Started turbine (13th start). EGT and main fuel P are still indicating low. Turbine ramped smoothly through start until I let off of the starter switch prematurely at about 45% RPM, causing the turbine to "bark" excitedly for a second until the governor got RPM to ~55%, then the governor and turbine settled down.
At lowest throttle setting (1,700 ohms) the turbine idled smoothly at about 55% without the C-clutch engaging. FCU lever was on idle stop 95% of the time, with the governor applying a slight gentle nudge (just off of the idle stop) every 5-10 seconds or so.
At idle detent (1,600 ohms), the C-clutch was engaging. Spun turbine up to 100% detent, adjusted GAC governor speed potentiometer to 100% = 520 M/R RPM as measured by hand-held Prop Tach. With M/R blades off, Main Fuel P = 80 psig and Turbine EGT = 300°F. Need to troubleshoot. Pushed governor Overspeed switch and after ~1/2 second the turbine shut down.
No oil leaks from T/R gearbox vent!!!
| 4/3/14 |
|Re-installed M/R blades prior to FAA Airworthiness inspection.|
|4/5/14||FAA DAR (Designated Airworthiness Representative) Inspection. Doghouse cowling, all aft fiberglass body panels and inspection panels were off. Removed front tub (nose) panel too for DAR to view electrical components and controls. Helicopter and paperwork passed and N105PS received its Special Airworthiness Certification.|
Made and installed new Rotax C gearbox custom oil return and vent fitting. Also, rather than using the original vent filter again, just ran 3/8" clear Tygon tubing from new vent fitting down to beneath the helicopter (similar to the T/R gearbox vent/overflow drain tube).
Machined new Westach EGT probe fitting and installed new thermocouple probe in turbine.
Wired and tested new EGT probe. Replaced 12' of type K thermocouple lead wires with standard 22 Ga aircraft wire from new thermocouple to Westach EGT gauge. (Original turbine EGT probe worked, but Westach EGT gauge is specifically calibrated for Westach EGT probe with 4' type K thermocouple lead wires, with white wire = positive, black wire = negative.)
Tested normally-closed Main Fuel Pressure Release valve and turbine Main Fuel P gauge. On start, Fuel P Release valve had no leakby, and with Main Fuel injector line capped, the Main Fuel P gauge indicated ~250 psi. (Start Fuel and the Exciter connectors were disconnected, then reconnected afterward.) All plumbing, valves, pressure senders and gauges appear to be operating properly.
Started turbine (14th start). Spooled up smoothly to 60% RPM and blades began turning before I let off of the starter. Turbine slowly spooled down to ~55% and blades eventually stopped.
Increased throttle to 60% detent and blades again began to turn. Matched needles at ~65% and slowly began to increase RPM. Significant instrument console vibration at 80% ~ 85% RPM. Much smoother at 90% - 100% RPM, once I centered cyclic properly. Alternator switch on, ran for several minutes. Reduced to idle and cooled down, then stopped.
Turbine EGT at 100% RPM, 0° pitch was ~500°F. Main Fuel P was still only ~75 psi.
No oil leaks from Rotax C gearbox vent!!!
| 4/19/14 |
Reattached nose panel. Reviewed RotorWay First Start videos and construction manual for rigging and control checks.
Since rotors were spun up to 100% the day prior, performed a M/R lead/lag check with two plumb bobs. Adjusted Slave blade ~0.050" (measured at rotor tip) forward. Also adjusted both M/R pitch links slightly for exact same pitch angle as measured by laser level point on the hanger wall.
Pushed it out at 16:30, OAT = 80°F. Turbine started (#15) smoothly to >55%, switched to M-GOV as soon as blades started to move, turbine barked once slightly and then settled back down to idle. Increased RPM, matched needles using 3°/1° pitch, took to 100% RPM. Less instrument vibration noted than previous day. EGT was 700°F.
Very carefully and slowly pulled collective over about 2 minutes, until helicopter was light on skids and I had tail rotor control. Played with cyclic to minimize vibration and forward/lateral movement on the ground. Was ~1,420 lbs, 4,000 ft D.A., EGT was 900°F, just shy of hovering for 6-8 minutes or so. Noted that M/R cooling fan switched on at 170°F, off at 140°F. Rotax C oil temp was 125°F, T/R oil temp 120°F. Turbine oil temp did not register, need to investigate. Thought I felt increased vibration, smelled oil, shut it down.
Since this was the first time the M/R gear box had ever done any serious work, it heated up and puked approximately 1 cup of oil out of the vent filter and all over inside the helicopter from the seat back to the turbine and everything down below.
Spent two hours mopping up oil all the way down the fuel tank and into the bottom tub. Way more cleanup to do still.
Noticed that the Rotax C box oil level was also low, but nothing in the new vent fitting and vent/drain tubing I had installed! Still need to investigate for any possible leaks elsewhere (but impossible to tell right now with all the M/R gearbox oil everywhere). Rotax C gearbox chip detect light was on as well.
T/R cog belt tracking was off, belt too far forward on jackshaft pulley. Lots of black rubber particles in oil everywhere. May be cause for increased vibration felt before shutting down?
| 4/20/14 |
|It turns out that most JetExecs are monitoring turbine fuel P right after the fuel pump, before the FCU. I am monitoring pressure on the main fuel injector line, after the FCU, hence the lower observed turbine fuel P's. I'll keep it this way a while.|
Removed jackshaft and alternator Ass'y and dis-Ass'ied. Thoroughly cleaned everything including belts, wires, components, frame, tank, electrical boxes, seat back, M/R, M/R drive, etc. etc. etc.
Relocated M/R vent to gearbox port furthest away from pinion gear. Peeked inside gearbox (looks shiny!) Refilled with 8-9 oz oil. Eliminated vent filter and ran 3/8" clear Tygon tubing from vent port down to rear landing gear leg, similar to C-box vent tubing.
Replaced and re-assembled jack shaft Ass'y, alternator, belts, etc. As per Dave D. at KISS, tensioned T/R drive belt to 5/16" deflection at 10 lbs one side. Dave said belt always wants to climb, so tension rear down to move belt rearward. Tensioned alternator belt too, and re-Tie-Wrapped/Zip-Tied all wires and hoses.
Turbine oil T sender tests open circuit, need to order new one.
Cleaned black sludge off of Rotax C box chip detector, added 3 oz oil to gear box. No leak found. Probably shook loose some air pockets from the cooling radiator when light on the skids previously.
Homer Bell to arrive today!
Added spacer washer to back of jackshaft Ass'y to try to move belt tracking aft. May also want to try torqueing vertical jackshaft support arms to rotate jackshaft axis counterclockwise.
Homer arrived, attached DynaVibe vibration analyzer to helicopter to trim M/R system. Started helicopter (#16), DynaVibe measurements determined that M/R master blade was 1/4 gram heavier than slave and need to lag slave 0.003" - 0.004". Tested tracking too, slave tracking was low, need to increase slave pitch.
Removed 1 small thin washer from end of master blade, increased slave pitch link 1/8 turn, started helicopter again (#17). DynaVibe said we slightly over-adjusted slave lag but vibration was only ~0.1 ips, so we left it there. Slave blade was still tracking low though so we increased pitch another 1/8 turn.
We started it again (#18). Homer picked it up and hovered it twice, 2~3 minutes. Marked blade tracking (with greased hose on a stick), shut it down. M/R gearbox was hot to touch but no oil leaks!
T/R cog belt is tracking better, still forward though. Might need to torque jackshaft Ass'y mount slightly. Homer said that belt is throwing a little mold-release wax, not rubber. Called it a day, took Homer to dinner.
| 4/30/14 |
Will try to balance T/R, optimize M/R tracking and hover today.
Examined M/R blade grease markings, slave blade now tracking just slightly high, could reduce slave pitch back 1/16 turn but left alone for now.
Turbine start #19. Homer balanced the T/R; vibration ~0.1 ips, was slightly heavy on the teeter bolt end (the T/R, not Homer), so sawed 2 threads off of the bolt end.
Turbine start #20. T/R vibration now ~0.07 ips, still toward bolt threads. Will saw off another 3-4 threads later.
Started turbine another 9-10 times (#21-#30). Got the helicopter airborne 4 times, hovering erratically all over the place (me, not Homer). Felt/heard the T/R cog belt ratchet noticeably during hard right pedal turns. Stopped doing hard right pedal turns. Checked T/R and drive shaft, then further practice hovering, taxiing, air taxi (50' at 50 mph), quick stops. Some vibration into and out of translational lift. Homer measured M/R blade reflex edges and adjusted two blade panels up slightly so both blades matched. Won't make any further adjustments until we see how everything handles in forward flight.
Fixed T/R cog belt tracking. The more angle we added to the aft end of the jackshaft Ass'y, the more the cog belt wanted to move forward. It turns out that once you have more than 0.5° of angle between the upper and lower pulley axis, the belt no longer climbs to the high side but instead gets pushed off. Removed washers and shortened jackshaft Ass'y adjustment bolt spacer (a short length of 3/8" PVC pipe I added to sleeve the adjustment bolt) and finally, the cog belt began to track closer to center on the upper and lower pulleys. Not throwing nearly as much mold release wax now either. Fortunately, we figured this out before resorting to using the torque hammer to tweak the vertical jackshaft support arms.
Increased tension on T/R drive belt from 5/16" down to 1/4" deflection at 10 lbs one side to prevent future inadvertent ratcheting.
Noted that the M/R gearbox pinion support flange TelaTemp high was 190°F, the new gearbox appears to be running well!
Good day! Took Homer to dinner!
| 5/1/14 |
Cleaned M/R blades (bug splatter and teeter block bearing grease) and inspected, looked good!
Cleaned cog belt wax off of engine area and inspected. M/R gearbox oil needs to be changed.
Inspected T/R drive shaft thoroughly. The #2 bulkhead flex rings (the first KISS flex ring coupler in the tailboom) were bowed outward every other segment where pushed when the cog belt ratcheted. Need to fix. The rest of the drive shaft, including the second set of KISS flex rings (#3 bulkhead) and the 7/8" u-joint I've added at the T/R gearbox, were O.K.
Fixed T/R shaft #2 bulkhead flex rings. Removed, split and swapped ring halves so outward bows now faced inward toward each other, rotated ring set 60° from original position, re-installed, and TorqueSealed nuts.
Changed T/R gearbox oil; cleaned, tested and reinstalled chip detector and refilled gearbox with clean oil. Chip detector light lit again, need to pull and clean detector again.
Still need to change M/R and Rotax C gearbox oil too.
Started (#31), ran turbine and rotors 0.1 hr. Drained M/R and Rotax gearbox oil and lines and replaced filter at Hobbs = 4.5 hrs. Both oils and filter were black with gear dust, but no visible metallic flecks or shavings. Refilled M/R gearbox with ~38 oz. and Rotax C gearbox with ~16 oz. of Valvoline HP 75W90, while continuing to break in these gears.
Had family and friends out to watch. Started turbine (#32), picked up and hovered around a little and landed without incident. Angel's Envy Kentucky bourbon is very smooth. Barbeque afterward at Skip and Bonnie's.
| 5/19/14 |
|Received and replaced Westach turbine gearbox oil temp sender. Then determined that old temp sender was O.K., just had cut wire near one of the 2,000 Tie-wraps/Zip-ties I have installed on the helicopter.|
|5/20/14||Tightened KISS M/R shaft top adjustment collar. Started (#33), hovered, taxied 0.7 hrs, landed, then magnetic card compass dropped off of windscreen and fell down around my foot pedals. Also, post-flight inspection revealed that turbine oil leaked/sprayed the entire time from where I had just replaced the temp sender.|
| 5/27/14 |
Fixed the turbine temp sender oil leak. Turbine gearbox oil level O.K. (1/2 on dipstick).
Removed shredded blue silicone applied to M/R upper bearing on 3/10/14, cleaned and re-sealed with blue silicone RTV again.
Changed T/R gearbox oil and cleaned chip detector again.
Added a little oil to the M/R gearbox (1/2 between marks on sight tube).
Carefully inspected T/R and drive shaft, all O.K.!
Wind 13 kts and incr. Chose not to fly today.
Cleaned windscreen for first time.
Recorded M/R blade reflex edge measurements for all 24 panels each blade. Decided that both blades were so similar that I should not mess with anything, did not adjust. Did lower M/R slave pitch 1/16 turn (from 4/30/14 tracking test), and permanently re-mounted magnetic card compass on windscreen.
Fueled to 80L. Turbine start #34. Hovered for 1 hr. Radio check (first time) O.K! Comm's good, and no apparent affect on governor or turbine RPM! Post flight inspection looked good! No leaks or runs, no drips, no errors! Hobbs = 6.4 hrs. Fuel burn for 1 hr hovering was (80L-24L)/1 hr = 56 Lph (almost 1 Lpm).
Re-fueled to 80L. Put on all body and inspection panels and doghouse. Turbine start #35. Checked traffic, made radio call, and took runway 30. Did 5 takeoffs, trips around the pattern and landings at EUL. The helicopter seemed to porpoise somewhat around 50 - 75 mph (quite possibly pilot-induced) but was still very controllable and very smooth! Had it up to 85 mph IAS at one point in the downwind without any problems. The turbine was always at 100% and (with noise-canceling Lightspeed headset on) incredibly quiet and smooth. It hovered, flew and landed very nicely, with no noticeable vibration from the rotor system. Hobbs = 7.15 hrs. Fuel burn for 0.75 hr hovering and flying in the pattern was only (80L-44L)/0.75 hr = 48 Lph (0.80 Lpm).
Did notice on startup (after 35 turbine starts) that the centrifugal clutch was getting slower to engage, will need to adjust.
Re-sampled Angel's Envy, it is still very smooth!
| 6/2/14 |
Marked and adjusted the 4 C-clutch shoes out 1/4 turn each.
Removed shredded blue silicone applied to M/R upper bearing on 5/27/14 and applied Loctite retaining compound from RotorWay parts to secure upper bearing to M/R shaft.
Refueled to 91L.
Started (#36), C-clutch began to engage right at ~55%, rotors came up to speed much more quickly at 60%-65% RPM.
Helicopter hovered very smoothly with 10 kt wind. Plenty of T/R authority to hover downwind, maintain position, turn either direction. Was ready for tail to lift in tailwind but it never did.
Takeoff in pattern was smooth and controlled, without any pilot-induced porpoising up to 75 mph. Everything fine! Second time in pattern downwind, took IAS up to 90 mph, O.K. Pushed up to 95 mph, O.K. Pushed up to 100 mph, O.K.! Pitch attitude definitely seemed nose-down. Started to ease back on forward cyclic (should have reduced collective first) and immediately pitched up hard and rolled right; pitch instability and retreating blade stall! Lowered collective slightly, re-applied some forward and right cyclic, regained control, made a second left turn downwind. Landed, idled, inspected, everything seemed O.K. (Note: All flying so far has been with both doors off.) (Second note: Oh yes, just remembered... Turbine Start/Shutdown checklist went out the passenger door 3rd takeoff on 5/29/14. Need to print a new one.)
Departed EUL 3 mi north to practice flying and autos over open fields. Began initial autos by progressively lowering collective until Rotor RPM exceeded 100% Engine RPM, at 65 - 75 mph. Maintained RRPM at 101%-104% easily, no unusual autorotation characteristics. Recovered from descent by gradually increasing collective while still at altitude. Returned to EUL, straight-in auto at 102% RRPM, 65 mph, flared intentionally high (~100' AGL) into a normal approach and landing. Taxied back to hanger, all gauges green, no chip lights, M/R gearbox temp ~140°F with cooling fan on.
Idled down, unbuckled, shut turbine down and climbed out. Heard ticking sound 1 per M/R rotation every time master blade passed over tail, definitely from M/R gearbox area. Was convinced that the M/R gearbox I had designed now had a damaged ring gear; began contemplating an unplanned, 1 year minimum re-design and rebuild. No Angel's Envy today.
Hobbs = 7.95 hrs. Fuel burn for 0.8 hr hovering, flying and autos was (91L-51L)/0.8 hr = 50 Lph (0.83 Lpm).
| 6/4/14 |
Bought a diagnostic inspection camera, Whistler Group WIC1296C, for $110 from O'Reilly Auto Parts. It has a 9mm dia x 1m long gooseneck camera with LED lighting attached to a battery operated hand-held 2.4" color monitor. Back out to the airport.
Ticking sound no longer heard when spinning the M/R. Removed doghouse and aft body panels. Drained all oil from the M/R gearbox and lines anyway. Snaked the camera into the gearbox and could easily view the contact area between the gears. Slowly turned the M/R many times and carefully inspected every tooth of both the ring and pinion gears and the entire inside of the gearbox. Everything looked very shiny, clean and smooth. Cleaned the magnetic chip detector. No evidence of chips, metal fragments, tooth chipping or any gear or bearing damage anywhere.
Refilled M/R gearbox oil, spun the rotor system and reprimed the oil pump and lines. Still no ticking sound heard.
No sign of oil ever entering the 3/8" Tygon M/R and Rotax C gearbox vent lines, so I shortened and re-routed them directly into the 1" Tygon fuel tank vent line up by the hood bracket.
Checked the T/R cogbelt tracking again, it is running slightly aft against the Sprag clutch housing. Might run slightly better by adding ~0.020" to the adjustment bolt spacer. Left alone for now though. Everything else looks good.
|6/6/14||Cleaned helicopter. Refueled to 80L. Pre-flighted carefully. Re-attached all fiberglass body panels, doghouse and inspection panels.|
Turbine start #37. Flew in pattern at EUL, did a few full-throttle autos terminating to a normal approach and landing. Momentary Hi RRPM alarm one time up to 110% entering one flare but everything O.K. Taxied back, landed, idled, shut turbine down, 1 per M/RRPM ticking sound was back. Dammit!
Found someone nearby to help me isolate the sound. I slowly spun the M/R and we were finally able to feel the clicking coming from the cooling oil pump, not from the M/R gearbox. Yippee! The cooling oil pump is a gear pump mounted directly beneath the M/R shaft. Although clicking, it still works fine; however I will remove and disassemble it during the next oil change.
Hobbs = 8.7 hrs. Fuel burn for 0.75 hr hovering, flying and autos was (80L-40L)/0.75 hr = 53.3 Lph (0.89 Lpm).
Refueled helicopter to 120L. Put TelaTemp sticker on side of oil pump.
Turbine start #38. Departed EUL 15 mi N to unpopulated foothills. 85 mph max airspeed, helicopter was easily controllable. Worked on autos and 60 - 65 mph navigation 100' - 200' AGL around the rolling foothills. No problems, fun easy relaxing flying. Returned to EUL and landed. Hobbs = 9.85 hrs. Fuel burn for 1.15 hr cross country and foothills flying was (120L-62L)/1.15 hr = 50.4 Lph (0.84 Lpm).
Inspected, started (#39), hovered, flew twice more around the pattern at EUL, put it away in the hanger for the day. Hobbs = 10.1 hrs. Fuel burn for 0.3 hr hovering, flying and autos was (62L-47L)/0.25 hr = 60 Lph (1.0 Lpm).
Total fuel consumption for the day for 2.15 hours of flying was 113L/2.15hr = 52.6 Lph = 0.88 Lpm = ~14 gph.
| 6/10/14 |
|Inspected and pre-flighted helicopter. Everything O.K. No temperature marks noted on oil pump TelaTemp (T < 180°F).|
|6/12/14||Mom, dad, brother Troy and his son Dan came out to see the helicopter fly for the first time. Turbine start #40, hovered for a few minutes down the taxiway and back, landed. M/R chip light came on and went out again, need to inspect. No ticking sound on shutdown though, no other problems.|
| 6/14/14 |
Cleaned black dust from M/R chip detector. No metal observed. Added ~0.015" to jackshaft spacer, belt runs just slightly off of the sprag housing now and centered on the jackshaft pulley below.
Pre-flighted and inspected carefully. Put all panels and doghouse back on (doors still off). Fueled to 100L.
Fathers Day! Turbine start #41. Taxied, air taxied, quick stops, maximum performance takeoff, flight in pattern around EUL. Checked compass while hovering over compass rose... hard to tell exactly from pilot seat, but all headings looked O.K. within 5°, which is better than my usual flight trim alignment. (I think those little trim strings lie.) Landed and inspected just because. Everything still looks good. No leaks, drips, rubber belt particles, vibration, chip lights, anything, except cooling oil pump still clicks 1 per M/R shaft RPM.
Turbine start #42. Flew pattern a few times, tried a few autos, still terminating high to a normal approach and landing. Need to get out away from the airport traffic for better practice area. Landed, post-flight inspection. I keep expecting something to break or fall off, but so far (Hobbs = 11.3 hrs) everything still looks great. Fuel consumption = (100L-43L)/1.1 hr = 52 Lph = ~14 gph.
| 6/19/14 |
Turbine start #43. Flew a little right traffic around EUL for a change. The helicopter turns right O.K. too. Departed EUL 15 mi N toward the foothills at 65 - 85 mph again. Low pass over Lauren and Dianne's house. Nobody out sunbathing, did not land. Flew foothills rim W to Emmett highway. Worked on climbs and descents: OAT = 80°F, DA ~6,000', EGT = 800°F and M/R gearbox oil T = 160°F with cooling fan not running while climbing 500 fpm. Autos from 4,000 ft (~1,000 ft AGL) with throttle at 90%; very controllable 65 mph 96% - 104% RRPM, terminating early ~100' AGL. Minor thermals on way back to EUL but no problems.
Landed in front of hanger, idled, shut down, oil pump ticking unchanged at 1 per M/RRPM. Oil temps were always good, oil color good, no chip lights, will change all gearboxs again and inspect oil pump at Hobbs = 15 hours. Rest of post-flight inspection A.O.K.
Hobbs = 12.4 hrs. F.C. = (90L-33L)/1.1hr = 52 Lph = ~14 gph.
| 6/22/14 |
Pre-flighted, fueled to 80L.
Turbine start #44. The helicopter was a little wobbly on its legs when I spun up the rotor system first thing this morning. The wind was blowing 8-10 knts along the hangers so I started facing a different direction today, and thought maybe I was getting some turbulence off of the roofs. As I got light on the skids there were several times that the nose of the helicopter shook laterally. It would come and go. I almost decided to shut it down, then the turbulence/shaking subsided and so I picked up the helicopter and hovered slowly out to the taxiway, no problems.
I practiced hovering with and against the wind for 10 or 15 minutes. The tail did lift once as I was coming around, but I had plenty of room to just go with it down the taxiway, lift slightly, turn and settle out.
Was hovering down at the end of the taxiway and the turbine power began to fluctuate. I couldn't see any tachometer movement but could definitely feel and hear (even with the noise-canceling headset on) a consistent rhythmical fluctuation in power. Every few seconds, the turbine would go RRRRRrrrrr, RRrr, RRrr, RRRrrr, kind of like the intro to AC/DC's Thunderstruck. Was still able to hover; hovered quickly back to the hanger without anything worsening and landed. Shut it down, still a ticking sound from the cooling pump, no other problems noted.
The power fluctuation had repeated consistently every few seconds. It seemed like it was a governor and FCU response to either repeating electrical noise, or to a repeating friction or load on the drive system. My radio was on, not stuck transmitting, hadn't caused problems with the governor previously. No indication of this problem any flight before.
Removed the doghouse and all aft fiberglass body panels. The T/R cog belt was up against the sprag housing and there was definitely a lot more particle shedding than noted previously, with some belt marks on the side of the sprag. It must be time now to tear everything apart again to see what's changed.
Hobbs = 12.7 hrs. F.C. = (80L-64L)/0.3hr = 53 Lph = 14 gph.
| 6/24/14 |
Pulled alternator and jackshaft ass'y. Alternator has some belt dust, belt was maybe a little too tight.
T/R gearbox and drive shaft spin freely with no noticeable change in friction over >100 revolutions (several T/R gear cycles).
Drained Rotax gear oil, was fairly clean still. Rotax chip detector measured 365Ω, had light coating of black sludge with few microscopic metallic flakes.
Drained M/R gear oil, was black. M/R chip detector measured >5MΩ, also had light coating of black sludge with few microscopic metallic flakes.
Cooling Oil Pump is rigidly mounted beneath the M/R shaft lower bearing flange as shown here. Unbolted everything but aluminum shaft collar was still securely stuck to bottom of M/R shaft. Didn't pull it, but did note a liberal coating of oil from the previous M/R gearbox oil leak, plus oil and black aluminum oxide fretting inside the aluminum collar. Cleaned everything.
Inspected the pump but did not disassemble. The pump shaft was tight but could be turned by hand and the gears meshed evenly and smoothly. Suspect that the rigid pump mount put undue stress on the pump shaft, especially when the long M/R shaft heats and expands, causing the ticking sound and fretting inside the collar when the pump rotates. Noted that the ticking sound was first noticed 6/3/14, soon after I had tightened the M/R shaft top adjustment collar on 5/20/14. Enlarged the lower four bolt holes and installed rubber grommets in the two mounting brackets to allow the cooling pump to flex a little. [Note: Replaced aluminum shaft collar with flexible rubber hose coupling on 9/27/15. See Oil Cooling System pictures.]
Inspected inside (bottom and top) of the M/R gearbox with camera. Ring and pinion gears looked perfect all the way around. Backlash seems greater than I remembered, need to verify.
Cleaned and reassembled everything, still need to add oil to gear boxes and optimize T/R cog belt tracking.
Didn't find anything that would cause turbine power fluctuation noted previously.
Filled M/R and Rotax gear oil and primed cooling pump.
Added ~0.010" to jackshaft ass'y spacer and belt tracking moved forward to just against front of jackshaft pulley. This is contrary to "Belt runs to the high side" theory. Need to look into this further.
Turbine start #45. Hovered for 0.7 hours. No immediate symptoms of turbine power fluctuation. Toward end I could detect some rythmic governor hunting about every 4 seconds. Came and went. Nothing as noticeable as on 6/22/14. I hate problems that disappear without knowing that you did something to fix them.
Landed and shut down. No ticking sound from cooling pump! However on run-down, did see that the 3/4" T/R drive shaft segment between the jackshaft and the tailboom u-joints was bowed slightly. Perhaps I had bent it accidentally against the bottom of the turbine gear case when checking everything and removing it the day before? Need to straighten it or build a new segment.
Hobbs = 13.4 hrs. F.C. = (64L-27L)/0.7hr = 53 Lph = 14 gph.
| 6/30/14 |
Removed horizontal stabilizer and added trim tabs with Gurney flaps to increase surface area and down-force. Trim tabs are 0.040" 5052 H32 aluminum and increase the horizontal surface area by ~15%. Estimated weight with aluminum, rivets and blade glue is about 6-7 oz.
Levered 3/4" T/R drive shaft segment with a flat pry bar until center wobble reduced from 0.045" to 0.003".
Reattached horizontal stabilizer. Topped off M/R and Rotax gearbox oil.
Checked horizontal alignment of jackshaft axis and upper drive axis with a laser pointer against sides of cog belt directed at the hanger wall, horizontal alignment was literally spot-on. No measurable horizontal misalignment to throw off the cog belt tracking. Vertical alignment of jackshaft axis is, as near as I can measure, within 0.1° of the upper drive axis, with the greater distance aft and the cog belt still running slightly forward. Go figure.
Reattached all body panels and doghouse; doors (still) off. Fueled to 90L. OAT = 20°C and climbing fast.
Turbine start #46. Hovered a little, flew right pattern once around EUL, then departed N toward foothills. Helicopter hovered and flew very smooth up to 85 mph. No indication of governor hunting or turbine power fluctuation. Just smooth. Slowly worked speed up to 100 mph IAS at 3,100' MSL (~4,500' DA). Gradually reduced collective and forward cyclic and eased back down to 85 mph again without incident.
Flew foothills awhile. Did hear governor / turbine power hunting a little once during slow forward flight, but changed helicopter attitude slightly and hunting stopped. Practiced 2-3 500 fpm climbs followed by autos at 90% ERPM, no problems. OAT now up to 80°F (27°C). 1,000 fpm climb once at 60 mph from 3,500' to 4,000' MSL (5,500' - 6,000' DA) with EGT and gearbox temps still in the green, no problems. Slowed down and tried to hover at 6,000' DA, but descent rate began to increase over 200 fps when I came out of ETL. Not shuddering yet, could have added more collective but flew out instead, will test HOGE limit another day.
Flew back toward EUL at 85 mph, 3,300' MSL (5,300' DA). Again slowly increased to 100 mph IAS and reduced again without problems. The new trim tabs / Gurney flaps seem to have improved the helicopter's pitch stability.
Landed (OAT = 30°C), idled, shut-down, climbed out and watched everything spin down. The 3/4" T/R drive shaft segment was running true. No ticking sound from the oil pump. No oil or fuel leaks or drips. No serious governor / turbine power fluctuations. Everything pretty much worked just perfectly! Good day!
Hobbs = 14.6 hrs. F.C. = (90L-25L)/1.2hr = 54 Lph.
| 7/10/14 |
|Stretched a ballpoint pen spring between turbine FCU and torque motor levers to eliminate slack in the swivel link connector rod ends. (See note from 3/5/14.) Fueled to 140 L = 37 gal = really close to max fuel.|
Turbine start #47. OAT = 80°F. With 140L fuel, 200 lb pilot, 50 lbs on the passenger floor, ballast weight forward, calculated takeoff weight ~1,430 lbs. Departed EUL south to Lake Lowell. After ~10 minutes flying, slowed to 0 IAS at 3,100' MSL (~600' AGL). Pulled collective to 500 fpm climb straight vertical, maintained EGT ~1,000°F. Ascended vertically to 4,500' MSL with 200 fpm climb rate remaining. Estim. weight with fuel burn ~1,400 lbs. OAT still 80°F, ~6,800' DA. Probably getting closer to HOGE limit (although I wasn't really "hovering" because I was still ascending vertically into clean air.)
Flew around Lake Lowell some, then further S to Marsing, along the Snake River to Homedale, then back toward Lake Lowell.
Flew at 60-65 mph IAS, climbing ~750 fpm to 8,000' MSL (1 mile AGL), maintained EGT 1,000~1,050°F. OAT = 70°F. Continued climbing ~500 fpm to 9,000' MSL. OAT = 65°F, ~11,400' DA with ~200 fpm climb and turbine power still available. Estim. weight with fuel burn ~1,350 lbs.
Began descent. Auto'd from 7,500' MSL to 4,000' MSL, had plenty of time to play with turns, airspeed and collective to maintain 100% RRPM. Would be nice to have GoPro video or data-logging GPS to record descent rate vs. various airspeeds.
Only noted slight governor hunting once during normal flight, nothing significant.
Returned to EUL, landed, hovered, air-taxied, returned to hanger and landed again. Little plastic suction cup with trim strings dropped off windscreen on ground in front of helicopter. (I really don't think I land that hard.) No other problems noted on run-down or post-flight inspection. T/R cog belt seems to have stopped throwing particles.
Tailboom was pretty sooty behind turbine exhaust. Added Telatemp inside tailboom skin beneath sooty spot.
Hobbs = 15.8 hrs. F.C. = (140L-76L)/1.2hr = 53 Lph = 14 gph.
| 7/26/14 |
Re-attached trim string suction cup. Fueled to 90L. Turbine start #48. Flew 15 mi S to Sunrise Sky Park, W above the mountains and back, N along the Snake River to Ste. Chapelle, around Lake Lowell and back to EUL, landed and inspected. Flew 1.5 hrs! No problems. No porpoising, no turbine governor hunting, no ticking, belt-ratcheting, wobbly drive shaft, oil leaks or cog belt particles inside the engine compartment. Tailboom Telatemp recorded 210°F beneath the turbine exhaust.
Hobbs = 17.3 hrs. F.C. = (90L-18L)/1.5hr = 48 Lph = 12.7 gph.
Fueled to 80L. Turbine start #49. C-clutch a little slow to engage. More hovering, flight around EUL and Lake Lowell. One 1,500 fpm climb to 3,500' MSL (OAT = 80°F, 5,300' DA) with EGT at 1,100°F. Turbine EGT Limit is 1,180°F. Returned to EUL. Tailboom Telatemp recorded 220°F beneath the turbine exhaust.
Hobbs = 18.1 hrs. F.C. = (80L-37L)/0.8hr = 54 Lph.
Removed doghouse and aft body panels. Cooling oil pump had leaked slightly since 7/2/14. Wiped clean slightly.
Drained M/R gearbox oil, was dark brown but not black. M/R chip detector measured >5MΩ, pulled and cleaned, had 1/16" coating of black sludge, no metallic flakes. Pulled and cleaned Rotax chip detector too; it also measured >5MΩ, had 1/32" coating of black sludge, no metallic flakes. Replaced M/R gearbox filter and oil.
Verified M/R ring and pinion backlash. Ring gear backlash is supposed to be 0.008"-0.010" at 7.125" O.D. = 0.15° of ring gear rotation, which with a 43:11 ring:pinion ratio = 0.60° of pinion gear rotation. Digital level on drive input to pinion indicated 0.6° of free movement or backlash!
Removed 0.005" more from jackshaft spacer, just because. Cog belt still runs forward against jackshaft flange.
Opened upper M/R shaft rubber boot, cleaned, greased, and re-sealed boot. Also greased M/R thrust bearing and teeter blocks and T/R slider and pivot pin bearings.
| 8/2/14 |
Reattached aft body panels and doghouse. Fueled to 90L. OAT = 34°C (93°F, airport = 5,000' DA).
Turbine start #50. C-clutch engaged O.K. Flew to Emmett, then above the Payette river all the way to Horseshoe Bend and back again, ~ 70 mi round trip. No problems, other than very faint 1 per MRRPM ticking sound on shutdown, hopefully from the oil pump again. (I think I may have stretched the M/R shaft a little more while banking above the Payette today!)
Hobbs = 19.3 hrs. F.C. = (90L-29L)/1.2hr = 51 Lph.
| 8/14/14 |
Son Kevin came out to see it fly. Turbine start #51. Only a short flight, twice around the pattern at EUL. No problems.
Hobbs = 19.6 hrs. F.C. = (29L-19L)/0.3hr = 33 Lph.
| 8/18/14 |
Fueled to 88L. Turbine start #52. Early evening flight through sunset to check out instrument lights and landing light. Awesome sunset! Instrument lights, landing light and everything else worked perfectly.
Hobbs = 20.5 hrs. F.C. = (88L-45L)/0.9hr = 48 Lph.
| 8/19/14 |
Turbine start #53. Flew around Lake Lowell and back to EUL. No problems.
Hobbs = 21.0 hrs. F.C. = (45L-20L)/0.5hr = 50 Lph.
Fueled to 135L. Turbine start #54.
Flew to Homedale (S66) and landed briefly.
Flew SE along Snake River past Marsing, Sunrise Sky Park. Landed on large plateau 4 mi N of Murphy (1U3). Huge plain, flat top, no way to get there but helicopter.
Flew further SE along Snake to Swan Falls dam and power plant, then returned along Snake and over Lake Lowell to EUL. Hovered a little and landed. Longest flight so far, 2 hours. Really sooty tailboom and a really sore tail, but no problems. (Note to self, need to find gel seat pad.)
Hobbs = 23.0 hrs. F.C. = (135L-33L)/2.0hr = 51 Lph.
| 8/23/14 |
It was cold and eerily quiet in the JetExec at 12,000' DA...
Fueled to 122L. Turbine start #55. Flew W to Wilder, then S and landed briefly again at S66, Homedale (creature of habit). Departed SW for the mountains, flew SE along the rim, discovered Jump Creek Canyon and Falls (I've never known they were there). Continued SE, then back up along the Snake River, N above Lake Lowell to the Boise River, then back along the tracks to EUL. Landed, then picked up again and departed N toward Emmett.
Removed doghouse cowling, chin and aft fiberglass body panels.
Port Nav light was dim and Stb'd Nav light was out. Traced to poor wire connector crimp behind instrument panel. Fixed.
Tightened cyclic clevis bolts to "snug-up" delrin bushings to reduce cyclic play.
Collective linkage was squeaky. Oiled swivel link ball at collective D lever behind seat.
Oil pump still leaks 1-2 drops/day, from shaft or somewhere on top of pump. Wiped clean.
Drained M/R, Rotax and T/R gearbox oils. M/R oil was black, Rotax and T/R oil was clear. M/R chip detector measured >5MΩ, pulled and cleaned, had 1/8" coating of black sludge. Rotax chip detector measured >5MΩ, pulled and cleaned, had 1/32" coating of black sludge. T/R chip detector measured >5MΩ, pulled and cleaned, also had 1/32" coating of black sludge. No metallic flakes noted anywhere.
Inspected M/R gearbox ring and pinion gears with diagnostic inspection camera, everything looked good!
Refilled M/R, Rotax and T/R gearboxs.
Pulled M/R blades. Master blade aligner block bearing was siezed and was just starting to burnish pitch pin. Did best to clean dried grease from inside bearing without removing aligner block from rotor blade and finally got bearing to loosen up. Made RotorWay's recommended custom bearing grease tool, greased both aligner block bearings and thrust block bearings, and re-installed both blades.
Greased M/R teeter block bearings, shaft thrust bearing, and T/R slider and pitch bearings.
Inspected frame, welds, turbine, main drive components, T/R shaft drive, T/R, all control linkages, wiring harnesses, all items on 25 hr maintenance and inspection program and then some. Reattached fiberglass chin panel.
Turbine start #56, engine run-up, took maintenance readings, shut down and inspected. All good.
Removed 0.010" from jackshaft adjustment bolt spacer and the T/R cog belt now runs to the rear against the Sprag housing again.
| 9/10/14 |
Fueled to 120L. Turbine start #57. Hovered a little, flew twice in the pattern around EUL. Everything felt good. Post-flight inspection all O.K. Replaced aft body panels and doghouse.
Hobbs = 25.7 hrs. F.C. = (120L-95L)/0.5hr = 50 Lph.
| 9/13/14 |
Doors on for first time, OAT = 45°F, zero wind. Turbine start #58. Repeat of 6/22/14 governor hunting problem. Nose shook laterally during runup for a little while, then settled down. Let everything warm up some and then picked up. Smoothest pickup I've had so far, but could still feel/hear periodic governor hunting. Switched alternator off for 5 minutes, no change. Hovered, taxied a while and problem eventually faded away.
Departed N toward Emmett. Planned to push a little closer to VNE since the doors were on, but never did go above 95 mph. (Chickened out, worried about aligner block bearings, rotor tracking and turbine/governor hunting.)
Decided to climb instead. Was about 1,300 lbs, hovered OGE at 6,000' MSL, (5,800' DA). Tried to hover OGE at 7,000' MSL (6,800' DA) but couldn't hold it there.
Continued climbing to No Supplemental O2 Limit of 14,000' MSL; at 1,100°F EGT the JetExec still had ~450 fpm ROC remaining.
Auto'd from ~13,500' MSL to 3,500' MSL, almost 6 minutes. 360°s, 720°s, figure 8's. Coming down from high altitude, turbine RPM did not want to drop below 100%, even with needles split at 102-104% M/RRPM. Rolled throttle off almost all the way to idle. Turbine RPM finally came down at around 6,000' MSL, and I throttled back up to 90% for the remainder of the Auto.
Returned to EUL, landed, shut it down. Post flight inspection all O.K. (still slight oil pump ticking.)
Hobbs = 27.2 hrs. F.C. = (95L-25L)/1.5hr = 47 Lph.
(Sorry, KML track data not available this time. I accidentially left Avare in Simulation mode and was really bummed to find that it did not record anything!)
| 9/13/14 |
Turbine Start #59, had help available to mark blade tracking. Slave blade was just slightly low, adjusted pitch link up ~1/32 turn.
Still need to fix a couple of things. Need to determine source of governor problem. Will try slight adjustments to governor Gain and Stability, and if problem still persists, switch off all electrical power except for A-GOV single battery circuit to governor.
Also, should tear cooling oil pump out again the next time I change oil, and disassemble/repair this time.
| 9/17/14 |
Reviewed governor manual and wiring diagrams last night and realized I had grounded the turbine speed sensor cable shield to ground. The governor manual says don't do that, "otherwise stray speed signals may be introduced into the speed control unit." Moved the cable shield over to "D", and ohm'd to make sure there was no other path to ground. This could be the source of my governor hunting problem.
Fueled to 125L. Turbine start #60. Noted very minor yawing at low turbine RPM and at 100% with no load, stopped when I began to pull pitch.
Helicopter hovered smoothly. Flew twice in the pattern around EUL, some (one per M/RRPM?) vibration at 85 mph.
Departed N toward Emmett. Seemed smoother. Weight ~1,380 lbs, got IAS up to 106 mph at 3,500' MSL, ~5,400' DA. Noticeably more vibration, but no problems.
Worked on climbing and 6 or 7 autos. Vy for most efficient rate of climb seemed to be around 55 mph, but very difficult to pin it down exactly with varying speed, pitch, EGT, and DA.
Returned to EUL, landed, inspected. Left horizontal winglet opened a thin 1" crack along the leading edge of the 90° bend. Everything else O.K. No hint of earlier governor hunting problem while flying.
Hobbs = 28.5 hrs. F.C. = (125L-59L)/1.3hr = 51 Lph.
| 9/19/14 |
Doors back off. Fueled to 100L. Turbine start #61.
Hovered and tested governor electrical. Helicopter has 3 separate power sources: the Main battery, Aux. battery and alternator. The Aux. batt powers only the governor. Either the Main battery or the alternator can power the rest of the helicopter and both back up the Aux. batt. Switched off various combinations (while on the ground) and hovered on each single system. No radio, instruments or pesky alarms with both the Main batt and alternator switched off, but the governor and turbine continued to hum along just fine.
Flew 80 - 95 mph to Emmett, Horseshoe Bend, Horseshoe Bend hill, flew by Skip and Bonnie's, back down along the Payette river to Emmett, EUL, Lake Lowell, returned to EUL.
Landed, inspected, zero problems. No further trace of governor hunting problem.
Hobbs = 30.1 hrs. F.C. = (100L-18L)/1.6hr = 51 Lph.
| 9/20/14 |
Fueled to 120L. Turbine start #62.
Flew past Lake Lowell and the Snake River, up Squaw Creek Canyon to Piute Butte (I think) and back to EUL. Landed for a water break.
Hobbs = 31.2 hrs. F.C. = (120L-60L)/1.1hr = 55 Lph.
Turbine start #63. Flew 6-7 turns in the pattern around EUL.
Hobbs = 32.0 hrs. F.C. = (60L-24L)/0.8hr = 45 Lph.
Removed doghouse cowling and aft fiberglass body panels. Inspected everything carefully. Everything looked really good, hardly even an oil drop on the cooling pump.
Drained M/R gearbox, changed filter, flushed cooler and filled with new oil. M/R oil was dark brown. M/R chip detector measured >5MΩ, pulled and cleaned, had 1/16" coating of black sludge. Rotax chip detector measured >5MΩ, pulled and cleaned it as well, had 1/64" coating of black sludge. No metallic flakes noted anywhere.
| 9/24/14 |
Replaced aft body panels and doghouse cowling. Fueled to 140L. 85°F OAT.
Turbine start #64. Couldn't get turbine/rotor tachometer needles to match at 65% turbine RPM so I shut it down. Had alternator on. Turned alternator off.
Turbine start #65. Got needles to match this time, slowly, C-clutch could probably use a little adjustment still.
Flew W to Owyhee River, Dam, Reservoir. Phenomenal canyon, rock formations and colors. Flew the reservoir to 28U, landed for a water break. Flew back up to the dam and cruised back E to EUL. Landed, shutdown, inspected, all good!
2.1 hr flight, probably about 100 miles round trip (still inside my 40 NM radius!) Hobbs = 34.1 hrs. F.C. = (140L-40L)/2.1hr = 48 Lph. 2014-09-24_14-04-09.KML.
Backed out C-clutch adjustment screws 1/8 turn.
|Had to take a few weeks off for work, weather and a wedding (my daughter's!)|
| 10/18/14 |
Doors back on again, OAT = 48°F, zero wind. Turbine start #66. Repeat of 9/13/14 and 6/22/14 governor hunting problem, though not as severe, still noticeable. C-clutch quickly engaged (quicker than I expected) near throttle idle and turbine power surged (helicopter yawed on the skids) occasionally while I slowly increased the throttle to full. At full throttle, the dual tach indicated 103%-104% turbine and M/R RPM, with turbine power still occasionally surging. Sat and warmed up for a while with no change. Switched off various combinations of electrical circuits, picked up, hovered and landed multiple times, still with no change. Turbine power continued to surge intermittently.
Landed, shutdown, inspected, nothing obvious. Frustrated, pushed it back into the hanger. Hobbs = 34.6 hrs. F.C. = (100L-71L)/0.5hr = 58 Lph (high, but had been hovering mostly).
Waited a while, then pushed it back out of the hanger to try once more before attempting any changes. OAT = 62°F. Turbine start #67. C-clutch engaged as it should with no apparent power surges. At full throttle, tachometer indicated 100%-101% turbine and M/R RPM. Helicopter hovered smoothly. Flew in pattern, then departed S to Lake Lowell. Flew W end of lake, felt surging return slightly. Returning to EUL, flew out of trim left, then right to see if problem was in any way related to T/R cog belt or drive load, but no apparent affect on intermittent surging, which eventually stopped.
Landed, inspected, everything still appeared O.K. Hobbs = 35.3 hrs. F.C. = (71L-39L)/0.7hr = 46 Lph.
The problem seems to be related directly to the governor or the turbine speed sensor input, with the governor occasionally trying to increase speed higher than is actually required. I previously checked the speed sensor voltage at the governor once on 3/19/14 and the voltage was good. Pascal suggested that I try swapping the speed sensor wires at the governor to invert the signal, I will try that next.
The problem may also possibly be temperature-related. The turbine seems to like to do this on cooler mornings.
| 10/28/14 |
Checked torque moter, FCU lever and linkage, nice and smooth, not sticky. Swapped C and D leads inside the govorner box to invert the turbine speed sensor signal to the governor, and increased governor gain from 40% to 50%. Governor stability at 40%.
2A Nav/Strobe light fuse was blown, upgraded fuse to 3A.
OAT = 57°F. Turbine start #68. Very smooth. Hovered for 0.3 hrs without any hint of governor hunting or surging.
Hobbs = 35.6 hrs. F.C. = (39L-26L)/0.3hr = 43 Lph.
| 10/30/14 |
Wanted to test flight performance at left lateral and aft C/G limits. Compared to the standard RotorWay Exec 162F, the JetExec is very tail heavy. To be in center of C/G limits, I fly solo with the 32 lb ballast weight forward on the right (passenger) skid and with 50 lbs extra weight on the passenger floor.
Fueled to 80L. OAT = 60°F. Turbine start #69. Hovered, no trace of governor hunting or surging. Landed, shifted 25 lbs from passenger floor to pilot floor and picked up again, with little noticeable difference in lateral attitude or cyclic position. Landed, shifted remaining 25 lbs from passenger floor to pilot floor and picked up again. According to W&B chart, this puts the helicopter at -0.9 inches, the far left lateral C/G limit. At far left limit, the helicopter still lifted off and hovered normally, again with little noticeable difference in lateral attitude or cyclic position. No unusual vibration and the helicopter still had plenty of right cyclic remaining.
Landed. Hobbs = 36.8 hrs. F.C. = (80L-19L)/1.2hr = 51 Lph.
Removed the 50 lbs extra weight from the helicopter floor to test flight performance at extreme aft C/G. According to W&B chart, this puts the helicopter at 99.5 inches longitudinally, 0.5 inches aft of the standard RotorWay Exec 162F aft C/G limit.
Fueled to 120L. OAT = 65°F. Turbine start #70. Picked up and hovered with noticeable nose-up attitude, but without vibration and the helicopter still had plenty of forward cyclic remaining. Flew pattern at EUL, then N to foothills. Flew for an hour or so and landed several times. More vibration than usual at 85-90 mph and cyclic definitely wanted to push right and aft (in all previous flights at normal C/G the cyclic usually stays centered). Returned to EUL.
On last takeoff attempt, suddenly developed significant M/R vibration through and continuing past ETL! Aborted takeoff, hovered back to hanger with continued bad rotor shake. Landed, inspected, couldn't see anything obviously wrong except that some paint had spalled off the seam between the upper two metal straps on the main blade. Initial M/R vibration that developed during takeoff was a severe reasonant vibration that felt like undampened or uncontrolled M/R feathering; obviously it had worked the straps a little. Couldn't see anything else wrong with blades or rotor system, began to worry I had ruined one or both elastomeric bearings by flying so long testing aft C/G.
Hobbs = 38.4 hrs. F.C. = (120L-39L)/1.6hr = 51 Lph.
| 10/31/14 |
Returned the 50 lbs extra weight to passenger floor to reestablish center longitudinal and lateral C/G.
OAT = 48°F. Turbine start #71. No trace of governor surging. Some light vibration while hovering and during takeoff, but nowhere near as significant as previous day. Flew S to Lake Lowell with noticeable M/R vibration that I hadn't had previously. Returned to EUL and landed.
Hobbs = 38.9 hr. F.C. = (39L-18L)/0.5hr = 42 Lph.
Turbine start #72. Checked M/R blade tracking. Slave blade now tracks just slightly high, made no adjustment.
Fueled to 140L. Turbine start #73. Idled up too slow, C-clutch was slipping, couldn't match needles at 65% RPM. Shut it down, waited 15 minutes.
Turbine start #74. Still some noticeable M/R vibration while hovering and flying, suspect lead/lag may now require adjustment. Departed EUL SW to Three Fingers Rock. Couldn't see any difference in blade tracking while flying.
Returned to EUL, worked on hovering for a while but couldn't (at least not very well, felt like fine motor skills were shot). Landed.
Hobbs = 40.6 hrs. F.C. = (140L-56L)/1.5hr = 56 Lph.
| 11/5/14 |
Removed dog house, chin and aft body panels. Leveled helicopter. Quick check of lead/lag by partially supporting M/R blades at 0° pitch with fishing line stretched blade end to blade end just above rotor mast. Fishing line was within 1/32" of mast C/L.
Laser-sighted along sides of hub and measured blade ends. (Note, both sides of hub are not exactly parallel with each other or pitch pins.) By measurement though, if blade C/G is 2.000" along 8" blade cord, master blade end appeared to run 0.151" forward of hub C/L and slave blade end appeared to run 0.164" forward of hub C/L.
Pulled both M/R blades and placed side by side on sawhorses. Used digital level to measure pitch angle along length of each blade:
Inspected, rotated and lubed M/R thrust and aligner block bearings, all good. Cleaned and inspected elastomeric bearing, which are less than 1 year old, and they both looked fine, so I reinstalled them.
With chin panel removed, carefully inspected electrical and control area. Cyclic lateral bushing were good but snugged bolts 1/4 turn further.
Discovered that one fore/aft cyclic cable nut was loose where cable sheath attached to frame. This (right) cable pushrod is normally under tension and the cable sheath is under compression. The rear cable nut was still compressed against the frame, allowing the fore/aft cyclic to still feel and function normally under light load, but when higher loads compress the pushrod the cable sheath would pull back away from the frame. This definitely would cause or allow the M/R blades to feather improperly!
Removed passenger cyclic access panel. Loose fore/aft cyclic cable nut was still Loctited and Torque-Sealed, but over time and with hammering, star washers had compressed under nut to allow 'snug' attachment to further loosen. Tightened all cable nuts very securely, re-Loctited and Torque-Sealed, replaced cyclic panel.
Measured runout on M/R shaft, still runs +/- 0.001" beneath hub.
Re-hung M/R blades. Loosened teeterblock, checked blade balance with water-level tubing. Water level showed main blade to still be heavy by ~1/2 thin washer, so removed thin washer and replaced #8 screw in blade end with one slightly longer. Blades leveled exactly. Reinstalled 3/8" teeterblock bolts.
Bubble level check indicated that slave blade lags just slightly. Master blade was a little sticky, but seemed to lead slightly. Did not adjust either.
Installed pitch links. Stepped M/R shaft 180° and compared pitch angles several times, slave pitch arm angle was about 0.1° to 0.15° higher, so based on 11/7/14 measurements above, slave blade pitch should be very close in line with master. Did not adjust either.
Pushed helicopter outside, doors off, 30°F'n cold and windy! Turbine start #75. No surging. C-clutch engaged and needles matched more quickly at lower (0°) collective setting, I think I had been spinning up the C-clutch at closer to 1° rotor pitch most times previously.
Could see pant leg twitch 1/4" or so with M/R RPM in open air cockpit, but no noticeable cyclic, collective or pedal vibration, until I started to pick up (aft cyclic to level rotor); then very little vibration when helicopter hung level again in hover. I could hover again! No vibration and didn't have to constantly correct cyclic.
Didn't venture out in the pattern. Landed, shut down and pushed it back into the hanger to change oil. Hobbs = 40.8 hrs.
Drained and changed Rotax and M/R gearbox oil and filter. M/R oil was black. Chip detector measured >5MΩ, pulled and cleaned, had >1/8" coating of black sludge. Rotax oil was light brown, chip detector measured >5MΩ, had <1/32" coating of black sludge. No metallic flakes. Cooling oil pump had leaked quite a few drops, either from the cold or just from sitting a while. Cog belt was still tracking aft against the Sprag pulley with some particles shed there.
Inspected M/R gears with camera again, all still good!
| 11/23/14 |
Refilled M/R and Rotax gear oil. Cleaned and inspected engine area and T/R drive shaft. Put doors on, left doghouse and aft body panels off.
Turbine start #76. OAT = 50°F. Flew 3x around the pattern at EUL. Takeoffs smooth, only a little (vertical?) vibration while flying in the pattern, but overall good! Landed, post flight inspection O.K.
Hobbs = 41.3 hrs. F.C. = (46L-22L)/0.5hr = 48 Lph.
| 11/24/14 |
Removed 0.005" from jackshaft spacer. Added 5 mil fiberglass tape beneath the two tailboom access panels to minimize chaffing. Replaced aft body panels and doghouse cowling.
Turbine start #77. OAT = 50°F. Flew N around foothills and back. Minimal vibration through different airspeeds, not much. Need to start adjusting M/R blade reflex edges now though for neutral collective pressure; hopefully rotor vibration will remain minimal. Flew for 1.4 hrs. Have not had any problems or even a hint of turbine surging since swapping the speed sensor wires to the governor and increasing gain to 50% on 10/28/14. Landed, inspected, everything good. Cog belt actually tracking in center of pulleys now!
Hobbs = 42.7 hrs. F.C. = (90L-19L)/1.4hr = 51 Lph.
| 11/26/14 |
Increased and carefully matched M/R blade reflex panels 2-7 +0.010". Fueled to 105L. OAT = 52°F. Turbine start #78. Hovered, flew once around the pattern at EUL. There was some increased M/R vibration and I think I could see ~3/4" blade tip tracking difference in flight. Still some downward collective pressure so will need to increase reflex edges further still.
Departed SW across Lake Lowell to Owyhee foothills. Landed above Jump Creek Falls for a break, took a picture.
Turbine start #79. Returned to EUL. Landed, inspected, everything O.K.
Hobbs = 43.8 hrs. F.C. = (105L-48L)/1.1hr = 52 Lph.
| 11/26/14 |
Recorded the following in N105PS logbook:
"I certify that the prescribed flight test hours have been completed and the aircraft is controllable throughtout its normal range of speeds and throughout all maneuvers to be executed, has no hazardous operating characteristics or design features, and is safe for operation. The following aircraft operating data has been demonstrated during the flight testing: speeds VS0 0 mph , VX 0 mph , VY 55 mph , and the weight 1,400 lbs and CG locations 97.5 in Long, -0.2 in Lat at which they were obtainied."
It's been fun. Thanks for hanging in there with me.
Last Updated: November 27, 2014 |
Send Mail to: Pete Swanstrom