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Old Bill

About Private Jets?

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I come to the Well one more time for Answers. In trying to cover more ground in a shorter time span, I have decided to move up from my Beech 200 to the Model of the Honda Jet by FSjets.com. As with all new Models it takes some getting used too. Time will remedy this , I'm sure. But I do have a nagging question. I get an overspeed alarm at 325 Knots. Reading the Specs it says this Aircraft is capable of 428 Knots at 41,000 feet. I realise that Airspeed is different from Ground Speed at different Altitudes. But I get the Alarm at all levels, whether flying level, climbing or descending. Is this Normal? And what can I do to correct it. Is this alarm set in the Aircraft.cfg file? Why the Hondajet you ask? Because I like the way it looks. I also like the looks of the Payware Eaglesoft Citation X. If I can Master this freeware , I'll Spring for the few bucks and the Payware. I appreciate all comments and replies about the Alarm problem and the Citation X. As to the Citation X, do I have to have a different version for FS9 and FSX?Bill :-hmmm :-violin :-beerchug

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"Reading the Specs it says this Aircraft is capable of 428 Knots at 41,000 feet.""realise that Airspeed is different from Ground Speed at different Altitudes. But I get the Alarm at all levels, whether flying level, climbing or descending."When aircraft specs are quoted in terms of max speed, they are always quoted in groundspeed. In other words, an aircraft capable of 428 kts at 41000 feet shouldn't have an indicated airspeed higher than roughly 210-230 kts at that altitude. Overspeed is based on reaching or exceeding a specific Indicated Airspeed which can be considerably lower than the max groundspeed of a jet.In a jet like the Honda Jet you should never come close to 325 knots indicated during any part of the flight envelope even if the overspeed doesn't kick in. The general rule if you want to be realistic in your flying is to not exceed 250kts indicated below 10000 feet and once in the flight levels, set your autopilot to hold mach, not airspeed. I deviate from the norm slightly after that--if my final indicated airspeed at cruise is say, 220 kts, I will set the autothrottle to 220 knots once I reach the flight levels and gradually lower my rate of climb to maintain that airspeed until cruise altitude. A better way is to set the autothrottle to a specific mach setting once you reach the flight levels (whatever is recommended for cruise climb for your jet). Regardless, you should be nowhere near 325 kts indicated, ever, in the type of jet you're flying. Others will chime in here with better explanations, but I hope it helps what I've explained.Regards,John Edit: I also noted you asked the same question in this thread:http://forums.avsim.net/dcboard.php?az=sho...&topic_id=45495I hope my answer clarifies things a bit for you. There's some good threads on flying jets in the forums--use the "search" feature if you want to learn more.

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428kts is the true airspeed(TAS), what you're reading off the airspeed indicator is indicated airspeed (IAS). the higher you go the more these two will differ from eachother.the calculations required to find TAS from IAS and the atmospheric conditions are beyond the scope of this post, but suffice to say that what was posted above is pretty accurate. 428KTAS (knots true air speed) is about 220-225kias (knots indicated airspeed, as shown on your airspeed indicator) at 41,000 feet.The switch from using KIAS to Mach as your speed reference usually happens in the high 20s, FL265-FL290.

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John, actually that's incorrect. When an aircraft speed is quoted its always in TRUE airspeed, NEVER quoted as groundspeed.Since the aircraft is not a car, it is never concerned with its speed over the ground. Ergo, an aircraft with a max TAS of 428 has a groundspeed of 528 with a 100kt tailwind or 328 with a 100kt headwind. To the aircraft it is still traveling at 428kts regardless of what the groundspeed reads so quoting GS in the aircraft specs would never be accurate except in calm winds at cruise (never). 428kt TAS is about 210-230 kts IAS. So he is trying to fly the aircraft at 428kts IAS which which will always exceed Vne at any given altitude for the HondaJet, or most jets except military fighters for that matter.Also at FL410 speed should be read in kts not TAS or IAS anyway. Since there are less air molecules at altitude hitting the pitot tubes that is the reason that the IAS reads a slower speed than at a lower altitude. The lower you go, the more air molecules hit the pitot, the faster the ASI shows, the higher you go the less molecules the slower the ASI shows. Which is why you go with a mach number which takes into account altitude and air temperature to show the correct speed. Of course, a given mach speed is different depending on altitude also.HTH,Mike T.

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Thanks Mike,I stated it incorrectly, but did understand that winds never factor into an aircraft's top speed quote. Thanks for clarifying my poor description.Regards,John

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Thanks Guys for the Input. But Ya still got me confused. By the way the Aircraft Specs say 420 knots, not 428. Nevertheless, if I can get this Baby up to where it says 420 on the Airspeed indicator, will I actually be going 500+ miles ground Speed? The reason I say this is because during my experimentation at 40,000 feet I set the Airspeed Hold Switch to 300 and was doing over 460 Knots Ground Speed without an alarm. Oh Yeah! I have no weather set, so there are no Winds aloft, either head wind or tail wind. And Nobodys answer cleared up why I get an overspeed Alarm at 325 knots. The Beechcraft I was flying never gave me an overspeed alarm unless I was in a steep dive at full throttle. And then only a little wing flutter. Simpler Times I guess.Bill, Old and Slow :-eek :-hmmm :-grr

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"if I can get this Baby up to where it says 420 on the Airspeed indicator, will I actually be going 500+ miles ground Speed?"That depends on your altitude--the higher you go the faster your ground speed (True Air Speed as Mike reminded me) in calm air. As stated in my earlier reply, you wouldn't attempt such a speed, ever. If you feel a need for speed, or want to "Kick the Tires and Light the Fires", go with an F-16 or something that can sustain a higher indicated airspeed.As far as the overspeed is concerned, every aircraft is different. Every aircraft has different overspeed limits. And some aren't modeled in the simulator to properly indicate overspeed. I suspect the King Air should fire an overspeed warning at less than 325 kts. indicated. Many of these aircraft you can research online to find out what their real limits are. Once you know them, try to fly within those limits regardless of what the simulator throws at you. And as noted in my earlier post, try to search the forums for the many tips out there on flying light and commercial jets.Regards,John

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Bill:1) If you want to see the actual 420kts airspeed on your airspeed indicator then you have to change the settings in FS9 from "Indicated Airspeed" to "True Airspeed". Real aircraft do NOT show True Airspeed (TAS) they show Indicated Airspeed (IAS) on the Airspeed Indicator. You need to understand the difference. - TAS is the actual speed of the aircraft through the air. In your case if you want to fly at a maximum of 420kts and you want your airspeed indicator to show 420kts then TAS will show this. -IAS is the speed of the aircraft taking into consideration the amount of air molecules ramming into the pitot tubes. Therefore, if you are flying at 250kts at 2000 feet, your airspeed indicator shows 250kts and that would be roughly your true airspeed AND your indicated airspeed. You will also see that the barber pole is pegged to the far right top of the airspeed indicator. HOWEVER, as you climb, your IAS will decrease even though you are flying at the SAME SPEED. If you establish a 300kt climb at 10,000 feet (you cannot go above 250kts below 10,0000) and you maintain that climb up to 35,000 feet your airspeed indicator will slowly wind down even though you are maintaining 300kts. As you approach FL410 your airspeed indicator will show ~210kts but you will be at ~420kts due to the fact that the indicator is getting less molecules hitting the pitot. Therefore ~210kts at 41,000 feet is ~420kts at sea level. To calculate the difference you need a flight computer, either handheld or onboard in the real world OR simply switch your ASI to TAS in FS9 and you will see the difference.Answer this question and you will have your answer. Which airplane is flying faster? A) An airplane flying at 300kts at 10,000 feet or an airplane flying at 300kts at 41,000 feet?Secondly, at FL410 you use %MACH and not IAS as your speed reference. 420kts at FL410 should be around MACH .74 or so.Also, groundspeed is NOT a factor in the speed of your aircraft. You aircraft doesn't care how fast its moving over the ground, regardless of the winds so ignore the groundspeed. GS is only a reference for your to understand the actual leg times of your trip and not the flight performance (ie, the speed at which you will overspeed).Since your Beechcraft cannot travel at speed approaching a high fraction of MACH nor can it cruise at FL410 you don't get these problems. The flight envelopes between a prop, turbine and jet are vastly difference therefore the requirements for understanding and flying these types of aircraft are vastly different!What I am explaining is basic airmanship, so I would highly suggest getting the Pilots Handbook of Aeronautical Knowledge as a reference. This is as simple an explaination of a complex topic as I can give :-)Hope this helps.Mike T.

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If you look at airspeeds in product literature they are usually quoted as TAS so prospective buyers can compare performance. TAS (in standard surface temperature and altimeter settings specified by the ICAO) with no wind considerations) is used as a reference. TAS for these "sale" specifications is used to compare range and performance and is usually published at maximum and economy performance environments.If your specs came from manufacturer's sales literature, treat all readings as such but do not expect to see these readings on your instruments.Some jet glass panels give you the normal IAS, CAS (TAS calibrated for temperture), and TAS. GS is also delivered on those equipped with reference systems such as GPS by measuring location changes over a defined time period.

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