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turner112

A few questions/observations: speed vs. climb

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Hi all-After having some real fun with the copters (which will only increase with trackIR) I have a few questions.I've only really goofed around so far - but it was -serious- goofing ;) and have been able to fly and land with a decent degree of accuracy. Some hard landings, but that's what soft seats are for!Anyway, I've noticed something similar to fixed-wing aircraft: supposing one is at full throttle, there is a maximum forward velocity and a maximum rate of climb. (All other things being equal.) Or, at least, it seems this way, and, if true, stands to reason that this is the case for the full range of collective combinations.So, my question is, I guess - just as in fixed-wing - are there "ideals" with copters, or is it more of a "do what you need" type-thing?That said, I don't have the throttle/collective separate (and should) but I just felt like asking.Now, if can get my computer working again, I'll try to find out for myself..thxAndrew

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Guest Captain Geoff

There are (at least in the military) charts for climb rate vs speed and most importantly weight. Weight, more than anything will affect the amount of torque needed, and the engine provides that only up to a point.The Navy Tactical Operations manuals (NATOPS) contain info on their helos. I'm not sure where you might find the info on civilian helos - but I presume the Pilot Operating Handbook (POH) would have it.Good luck.Senior Captain, Pier Glass Aviation

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>Hi all->>Anyway, I've noticed something similar to fixed-wing aircraft:>supposing one is at full throttle, there is a maximum forward>velocity and a maximum rate of climb. (All other things being>equal.) Or, at least, it seems this way, and, if true, stands>to reason that this is the case for the full range of>collective combinations.In piston-powered helicopters, the throttle is used only to establish the desired main rotor rpm - once the rotor is spun up to a specified RPM, you will, in a helicopter without a throttle governor, only be making subtle throttle changes, and that is only to maintain the rotor rpm "in the green" area of the MRRPM (main rotor RPM) gauge, which is quite small (the green area, not the gauge 8^) ). If the aircraft has a throttle governor, then that will take care of itself, right up until you ask for max available engine power - after that, you will experience "MRRPM droop" and your day will get real interesting real fast.The maximum climb rate of any helicopter is defined by (a) maintaining MRRPM "in the green" while at maximum throttle (piston) or fuel control setting (turbine), and (:( maintaining a forward airspeed that keeps you out of the "dead man's curve" - see below.All turbine helicopters (including the FS9 206) have automatic throttle - or more accurately, fuel flow - management so once you've set the desird MRRPM on the twist grip, you won't worry about that unless you have some sort of emergency, like a fuel controller failure. Some piston helicopters (e.g. all Robinsons) have a MRRPM governor which makes for a lighter pilot workload. This is an option on the Schweizer 300C, for instance. All helicopters modeled in FS9 have a virtual governor, be they the included Bell 206/R22 or aftermarket aircraft (see www.hovercontrol.com for a boatload of free add-on helos).>>So, my question is, I guess - just as in fixed-wing - are>there "ideals" with copters, or is it more of a "do what you>need" type-thing?I'm not going to try to answer this simple question with the complex answer that it needs - it's too late at night here 8^) - but briefly, there is an optimum climb-out speed that needs to be maintained, in order to keep you out of the so-called "dead man's curve" that all helicopters have by their very nature (i.e. autorotative characteristics). This specifies what forward speed you need to keep at various altitudes, so that in the event of an engine failure you won't die screaming like a little baby 8^) - i.e. that you have enough time and/or altitude to establish an autorotative descent and subsequent safe landing. Autorotation requires that the airflow be flowing "up" through the main rotor system to make it spin Round and Round (and thus provide lift), and getting the previously downward (engine driven) airflow to reverse takes some time..."Approach" (maneuvering to land) speeds are a bit different, and are highly dependent on the wind/temperature conditions, but again they're specified to keep you and your ship in a position and energy management state to be able to successfully abort an approach if something doesn't go right (e.g. the wind direction changes on short final, the engine quits or gets suddenly tired, or perhaps it's a very hot day and you run out of the power required to make a safe landing - (but the latter is unlikely if you've done the appropriate "power available checks", which is a topic unto itself).Note that in the real world, commercial helicopter pilots, in some types of operations, are regularly putting their aircraft and themselves into a high risk situation (i.e. one that if the engine quits, they will most likely *crash* and not have time to enter autorotation). That is why those guys make the Big Bucks. Or perhaps better stated, Less Sucky Bucks than they made when they were CFIs...>>That said, I don't have the throttle/collective separate (and>should) but I just felt like asking.FS9 doesn't model the collective correctly, so having a separate throttle axis assigned isn't particularly useful. (I.e., if you lower the collective and simultaneously roll off the throttle, which is how you'd practice an autorotation in a real helicopter, your FS9 helicopter will fall out of the sky due to a very rapid MRRPM decay. This is totally inaccurate - lowering the collective should never *lower* MRRPM. (Workaround - pull just a tad of collective back up to maintain MRRPM. This is reeeeeeally counterintuitive and I hope they fix this in FS-X.)Also, the throttle axis seems to be an "on" or "off" control - FS9 gives no sense of managing MRRPM in any helicopter that you can download (let alone the provided Bell 206 or R22).>>Now, if can get my computer working again, I'll try to find>out for myself..Good luck with that.>>thx>Andrewcheers,Dave Blevins


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