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iChris last won the day on April 27 2020

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  1. You asked, "anyone heard of a tail rotor consuming > 15% power?" absolutely. Flight envelopes account for more than that. The numbers are a result of a specific design. There are no metrics other than that from a specific design. Roughly, the tail rotor consumes up to about 10% of the total power for the helicopter. However, allowances of up to 20% may be made for design purposes to ensure sufficient maneuvering and transient capabilities. We can also look at it as a percentage of the total main rotor power. The power required by the tail rotor typically varies between 3% and 5%
  2. The text you quoted states that "cruise-charts are not drag-charts, it can be noted the lowest point of a drag chart does not necessarily match the lowest point of the power required curve in a cruise chart." As in Eric Hunt's post above, D = P/V. Were P = rotor power (induced, profile) + the rest of the helicopter (parasitic, tail rotor). Eric already answered your question as to why. It's in the math, rearranging the equation D x V = P. It's a helicopter, not just D = P. You have to account for the V and the other power requirements. We're dealing with the total power r
  3. Refer to the specific series noncommercial/military flight manual. Maybe informational status only indication. Example Army OH-6A manual section below, even though calibration is also 35 pounds:
  4. In FAA’s eyes a "small rotorcraft:" 14 CFR Part 1.1 defines a small aircraft as an aircraft of 12,500 lbs. or less maximum certificated take-off weight. Therefore, any rotorcraft, could be considered small by the Part 1.1 definition (aircraft) if the rotorcraft/helicopter is less than 12,500 lbs. Part 1.1 Aircraft means a device that is used or intended to be used for flight in the air. Part 1.1 Small aircraft means aircraft of 12,500 pounds or less, maximum certificated takeoff weight. § 29.811 (f) Each emergency exit, and its means of opening, must be marked on the outs
  5. Your speakers are not polarity sensitive so bands 2 & 4 (speaker wires) on the u174 may be reversed wired without a problem. The same for the mic bands 1 & 3 (mic). In most cases the mic is not polarity sensitive. However, with an older mic or special purpose designs, you may have to swap the mic wires around. Once you identify your mic wires, any reverse polarity won’t hurt the mic, it just won’t work, just swap it. Your PTT switch above is yellow/black wiring between your radio and the u94. It could be one or two wires. The one wire setup eliminates the extra wire run by usi
  6. From your post, I assume you’re trying to replace the u-94 jack with a u-174 plug or trying to make an adapter cable with a u-174 at each end so as not, destroy the u-94 jack. With the documentation at the link below, you should be able the back-track the wiring. Open up the u-94 jack and plug in the u-174 plug. From there, you can back-track the known wiring form the u-174 back to the correct connections on the u-94 side. You can also see how the David Clark H10-76 u-174-plug wiring matches up with the u-94. It’s not as hard as it may seem, the system effectively (on the headset end
  7. It appears your memory hasn't failed you. At least that was the way it was before Airbus. Maybe the qualified flight instructor requirement part came in later manuals.
  8. The ability of the compressor to pump air is a function of RPM. At low RPMs, the compressor does not have the same ability to pump air as it does at higher RPMs. To keep the blade angle of attack and air velocity within desired limits and prevent compressor stall, it is necessary to "unload" the compressor in some manner. In other words, the compressor needs to see less restriction to the flow of air through the use of a compressor bleed air system. CLICK PHOTO TO ENLARGE
  9. You don’t need to rebuild the R22/R44 helicopter or overhaul its engine. However, regardless of the certificate, the aircraft has to be airworthy. It is well-established that an aircraft is deemed 'airworthy' only when it conforms to its type certificate (if and as that certificate has been modified by supplemental type certificates and by Airworthiness Directives), and is in condition for safe operation. Experimental won’t get you pass that. It's a documented practice in line with FAR 43.15c and Appendix D to Part 43. If the aircraft is not used for compensation or hire it could be oper
  10. NTSB Updates on Kobe Bryant Accident A ground camera captured an image of the helicopter entering the clouds. Radar/ADS-B data indicate the aircraft was climbing southwesterly along a course aligned with Highway 101 just east of the Las Virgenes exit, between Las Virgenes and Lost Hills Road. The helicopter reached an altitude of 2,300 feet msl, approximately 1,500 feet above the highway, but below the surrounding terrain when it began a left turn. Eight seconds later, the aircraft began descending as the left turn continued. The descent rate increased to over 4,000 feet per minute w
  11. The quote was Aviation accidents.... Job-related mortality of wildlife workers in the United States, 1937-2000 “Abstract Wildlife biologists face a variety of job-related hazards that are unique to this profession, most of them involving the remote areas where work is performed and the unusual techniques used to study or manage wildlife. Information on biologists and others killed while conducting wildlife research or management was obtained from state and federal natural resources agencies, solicitations on wildlife-based internet discussion groups, and published obituaries. N
  12. That S-76B was operated single-pilot VFR, Part 135 charter, limit 9 PAX seats. That wasn’t an IFR operation. That’s also why neither Cockpit Voice Recorder (CVR) or Flight Data Recorder (FDR or Black Box) are required (135.151 or 135.152).
  13. The 90gal/hr is a bit high for single engine operation. However, that's in the range with both engines online, 0.5 - 0.6 (80 - 97 gal/hr ) in terms of efficiency, you're looking for < 0.7 SHP(takeoff) = 1100 (0.5 * SHP)/6.8 = 80gal/hr (0.6 * SHP)/6.8 = 97gal/hr
  14. There’s a typical 0.5 - 0.8 Ibs/hp/hr specific fuel consumption (SFC) index for modern turbine engines. Light helicopter turbines, 0.5 is a good average The Bell 429’s one engine inoperative (OEI) 30 minutes hp = 550 SHP. So your OEI would average around: 40gal/hr. @550 SHP (jetA est. 6.8lbs/gal)
  15. You take calculated risk every time you go and fly. It’s how you manage that risk, how you plan ahead for it, and deal with it that makes it dangerous or not dangerous. One thing is sure, dangerous or not, it’s unforgiving of poor decision-making
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