roo-d Posted December 25, 2008 Posted December 25, 2008 Hi folks! First of all, this is an absolutely awesome sim :D! Really great work so far... Thanks ED :thumbup: My problem (or a bug?): for landing with autorotation, I set the engine to idle. before touchdown I raise the collective and come to a hover. I can hover and hover for hours, or even takeoff again, leaving the power on idle. The engine winds up to full power, when I raise the collective, and that's not how it should be, is it? Rudy
ED Team Yo-Yo Posted December 25, 2008 ED Team Posted December 25, 2008 You can... you surely can but try to fly at idle when you are full loaded... you just have lack of engine power flying at idle. It's funny but some guys complaines that they have low rotor rpm and they run without AC generators.... :) The right answer is : AT IDLE. Ніщо так сильно не ранить мозок, як уламки скла від розбитих рожевих окулярів There is nothing so hurtful for the brain as splinters of broken rose-coloured spectacles. Ничто так сильно не ранит мозг, как осколки стекла от разбитых розовых очков (С) Me
AlphaOneSix Posted December 25, 2008 Posted December 25, 2008 Just like Yo-Yo said, if the aircraft is light enough, it will fly at IDLE power. Fill it full of gas and put 4 ferry tanks on the wings. That should glue you to the ground pretty well!
RvETito Posted December 25, 2008 Posted December 25, 2008 Also, the fuel control unit is not set to maintain 90% rotor RPM with throttle lever at IDLE. Because the engine fuel flow control is slaved to the collective, the GG RPM follows it but it's metering the fuel flow proportional to collective (respectively throttle lever on the engine control unit) position, not to rotor RPM. 1 "See, to me that's a stupid instrument. It tells what your angle of attack is. If you don't know you shouldn't be flying." - Chuck Yeager, from the back seat of F-15D at age 89. =RvE=
AlphaOneSix Posted December 25, 2008 Posted December 25, 2008 Also, the fuel control unit is not set to maintain 90% rotor RPM with throttle lever at IDLE. Because the engine fuel flow control is slaved to the collective, the GG RPM follows it but it's metering the fuel flow proportional to collective (respectively throttle lever on the engine control unit) position, not to rotor RPM. I had to laugh when I read this, because I spent about an hour studying just how this exact process works yesterday at work (engine book 2, 073.12.05). :book: :D
RvETito Posted December 25, 2008 Posted December 25, 2008 Yep, that's what this engine is all about- if you understand when each of the governors (gas-generator RPM governor, power turbine RPM governor, electronic engine RPM and EGT governors) controls the fuel flow in the entire range of the fuel control unit throttle lever (from 0 to 120), the rest are just details. "See, to me that's a stupid instrument. It tells what your angle of attack is. If you don't know you shouldn't be flying." - Chuck Yeager, from the back seat of F-15D at age 89. =RvE=
roo-d Posted December 25, 2008 Author Posted December 25, 2008 Just like Yo-Yo said, if the aircraft is light enough, it will fly at IDLE power. Fill it full of gas and put 4 ferry tanks on the wings. That should glue you to the ground pretty well! I just flew a bit around, with four ferry tanks on the wings! Throttle on IDLE. The engine RPM goes to 100%, even the limiter lights go on. I can't belive this is the real thing. Rudy
RvETito Posted December 25, 2008 Posted December 25, 2008 How is the rotor behaving? ;) "See, to me that's a stupid instrument. It tells what your angle of attack is. If you don't know you shouldn't be flying." - Chuck Yeager, from the back seat of F-15D at age 89. =RvE=
roo-d Posted December 25, 2008 Author Posted December 25, 2008 Rotor RPM is 80% when hovering and 77% when climbing. Now, for real autorotation training, I will close the cut-off valves :).
RvETito Posted December 25, 2008 Posted December 25, 2008 Care to know what the yellow stripped light and sound warning means? Also, how was the picture of the Shkval at 77%? ;) The bottom line is that this is possible IRL but it is nonsense, it's like trying to hit top speed with your car at 3rd gear. "See, to me that's a stupid instrument. It tells what your angle of attack is. If you don't know you shouldn't be flying." - Chuck Yeager, from the back seat of F-15D at age 89. =RvE=
roo-d Posted December 26, 2008 Author Posted December 26, 2008 (edited) I totally agree with you, AirTito. It's nonsense to fly this way (and dangerous, too :D). I was looking for an answer to this simple question: Why goes the engine up to 100%, when the power is set to idle and I raise the collective? Edited December 26, 2008 by roo-d!
RvETito Posted December 26, 2008 Posted December 26, 2008 Hehe, the 1 million $ question. I'm usually getting paid when I'm explaining this but this time around you get a Christmas discount :D On the engine fuel control unit (FCU) there is a throttle lever controlled both from the yellow lever in pit and the collective. At IDLE this lever is at 0, the maximum postition is 120. When you move the yellow lever from IDLE to AUTO the lever on the FCU moves from 0 to 48 and in normal operation you don't move it from there in flight. With the collective you move it from 48 to 120, you have 72 degrees range with the collective. When the yellow lever is at IDLE and you pull the collective full up you will move the FCU throttle lever from 0 to 72. The gas-generator RPM governor at IDLE maintains ~72%. When you start moving the FCU lever up (either with the yellow lever or collective) the RPM settings of the GG governor start to increase in linear function and at 70 degrees the GG governor settings reach the maximum settings, usualy a little more than 101%, slightly above the EEG (electronic) limiting threshold. That means that you can have maximum engine power available by pulling the collective only but this most likely won't be enough to maintain rotor RPM 90%. "See, to me that's a stupid instrument. It tells what your angle of attack is. If you don't know you shouldn't be flying." - Chuck Yeager, from the back seat of F-15D at age 89. =RvE=
roo-d Posted December 26, 2008 Author Posted December 26, 2008 Could you explain that in more details, please? :megalol: Thanks AirTito, that's just what I wanted to know! Rudy
RvETito Posted December 26, 2008 Posted December 26, 2008 Could you explain that in more details, please? :megalol: No problem, I'll let you know my bank account :D "See, to me that's a stupid instrument. It tells what your angle of attack is. If you don't know you shouldn't be flying." - Chuck Yeager, from the back seat of F-15D at age 89. =RvE=
X-Raptor Posted January 26, 2009 Posted January 26, 2009 Hehe, the 1 million $ question. I'm usually getting paid when I'm explaining this but this time around you get a Christmas discount :D On the engine fuel control unit (FCU) there is a throttle lever controlled both from the yellow lever in pit and the collective. At IDLE this lever is at 0, the maximum postition is 120. When you move the yellow lever from IDLE to AUTO the lever on the FCU moves from 0 to 48 and in normal operation you don't move it from there in flight. With the collective you move it from 48 to 120, you have 72 degrees range with the collective. When the yellow lever is at IDLE and you pull the collective full up you will move the FCU throttle lever from 0 to 72. The gas-generator RPM governor at IDLE maintains ~72%. When you start moving the FCU lever up (either with the yellow lever or collective) the RPM settings of the GG governor start to increase in linear function and at 70 degrees the GG governor settings reach the maximum settings, usualy a little more than 101%, slightly above the EEG (electronic) limiting threshold. That means that you can have maximum engine power available by pulling the collective only but this most likely won't be enough to maintain rotor RPM 90%. YES please Tito give us your bank transfer number, as me too need to knok the secret of how to use yellow Rpm bottom-left gauges, it's not at all clear and me too think I'm flying with IDLE:cry:, THANK YOU...
-sulan- Posted January 26, 2009 Posted January 26, 2009 hehe.. I flew my second flight at idle, I made a very brief touch and go in a bush, and proceeded to land back at the base on only the main gear.. :D But I did'nt crash, I was very proud.. :)
X-Raptor Posted January 26, 2009 Posted January 26, 2009 4 times press PagUp + RShift/LShift = Full trottle!:D
ruprecht Posted January 27, 2009 Posted January 27, 2009 So could I ask how the real pilots practice autos in the shark, if setting the throttles to idle is not a reliable way to get 0 torque to the masts? I'm assuming they don't just pull the fuel cocks and practice the hard way! Or does the checklist look like this: AUTOROTATION - One engine out --- dump stores --- fly away - Two engines out --- Eject ;) DCS Wishlist: | Navy F-14 | Navy F/A-18 | AH-6 | Navy A-6 | Official Navy A-4 | Carrier Ops | Dynamic Campaign | Marine AH-1 | Streaming DCS sometimes:
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