At the right altitude and with favourable wind the citation can do 340 ground speed or TAS

 

I typically see 280-310 ground speed at around FL250 and the wind isn't fighting me.  You'd probably get more speed higher up.

This is an interesting topic, in that I fly only GA aircraft, and have found myself somewhat disappointed in the limited cruise speed, even for the GA jets like the Flight1 Mustang.

 

On a whim I flew the FS-Cast B-17 Flying Fortress the other night. Handles like a bus, not terribly quick on the take-off roll, but damn, it easily cruises at 250 MPH. This from a WWII aircraft with the aerodynamic profile of a brick! I guess there really is no substitution for cubic inches!  

 

And as Ryan indicated, the A2A P-51 Civilian is a rip-snorter, easily cruising at 350 MPH. This is faster than everything I have in my hanger with the exception of the stock Learjet (which I DO NOT like to fly) and the Blue Angels modified F-18 (which I LOVE to fly).

 

I kind of expected that the Flight1 Mustang VLJ would be able to pull similar speed as the P-51 Mustang, being a jet and all, but nope - peters out pretty quickly, much earlier than the performance of the engines suggests. Wikipedia says it is supposed to cruise at 340 kts, but my version has a big red bar starting at 250 kts (IIRC) and it starts barking at me to slow down. The upcoming Embraer Phenom from Caranedo might be better, but we will only find out. 

 

Have others found the speed of (admittedly a small sample) GA jets to be disappointing?

 

 

 

I think you have indicated airspeed and true airspeed confused. Higher up the 250 indicated on the Mustang will be much faster than the B-17

I think you have indicated airspeed and true airspeed confused. Higher up the 250 indicated on the Mustang will be much faster than the B-17

 

Hi Glenn, 

 

Could be. I just read it off the flight instrumentation, with both around 3,500 ft.

 

It also does not help that the B-17 has MPH and the P-51 uses knots.

 

But, since the P-51 Mustang says 350 kts, in steady flight, and 400+ in a dive, I have to assume that is indicated airspeed, i.e., the speed of air flowing past the fuselage. And I don't imagine a B-17 even knows what "true airspeed" is.

Well the wiki speed for the Mustang is probably in ground speed. The 250 would be indicated airspeed IAS. At the right altitude and with favourable wind the citation can do 340 ground speed or TAS

Heya Lee, 

 

Forgive my ignorance as I am not a pilot, but doesn't True Air Speed seem to have a lot of fudge-factor built into it? We gear-heads used to joke that a VW Bus could pull 100 MPH if you threw if off a cliff, but that was no indication of "true performance". 

 

I understand the "why" for TAS, but do not see how anybody (Wikipedia, et al) would promote that as a value of merit. Is it, as Ryan suggests, only true at very high (for GA!) altitudes?

I would guess he is looking for something low level for sight seeing GA flights so 400kph means a chunk more the 200kts.  Lancair Legacy is a great aircraft but isn´t quite that fast at low level.

 

Why don´t you pretend you got a bit extra cash and buy the Lotussim L39.  Plenty private owners, not actually that fast and great fun!

Real Air legacy and A2A Civ Mustang are great planes and pushing the GA definition would give you the Eaglesoft Citation X which is the fastest civ jet you can fly.

Hi Glenn, 

 

Could be. I just read it off the flight instrumentation, with both around 3,500 ft.

 

It also does not help that the B-17 has MPH and the P-51 uses knots.

 

But, since the P-51 Mustang says 350 kts, in steady flight, and 400+ in a dive, I have to assume that is indicated airspeed, i.e., the speed of air flowing past the fuselage. And I don't imagine a B-17 even knows what "true airspeed" is.

Heya Lee, 

 

Forgive my ignorance as I am not a pilot, but doesn't True Air Speed seem to have a lot of fudge-factor built into it? We gear-heads used to joke that a VW Bus could pull 100 MPH if you threw if off a cliff, but that was no indication of "true performance". 

 

I understand the "why" for TAS, but do not see how anybody (Wikipedia, et al) would promote that as a value of merit. Is it, as Ryan suggests, only true at very high (for GA!) altitudes?

 

Think of it in groundspeed terms.

 

Very simply, 250 KIAS at 3,000 feet is very different from 250 KIAS at 25,000 feet.

 

the 250 KIAS at 25,000 feet would be much faster in groundspeed terms. (lets forget about winds and such for now)

Why the quest for speed ??  

 

Flights too long, and you are getting bored ?

 

Try flying in a busy Multiplayer session,  and correctly using checklists, and flying to a prepared plan, and you may wish for something a little SLOWER, so you can keep up.

Forgive my ignorance as I am not a pilot, but doesn't True Air Speed seem to have a lot of fudge-factor built into it?

 

No.  True airspeed is just that - TRUE.  It is the actual speed at which you're moving relative to the airmass you're in.  At sea level and standard conditions, IAS (well, actually calibrated airspeed) = TAS , but as you go higher, the gap grows.

 

There's no "fudge-factor", and the number can be calculated precisely from IAS if you know temperature and pressure.  You can also approximate TAS by adding @2% per 1000' of altitude to your IAS.  You can see what a difference this starts to make, as at FL200, for example, TAS is 40% faster than IAS.

 

Scott

Carenado TBM 850, single engine turboprop capable of 320 KTAS at FL240, equipped with a decent GNS1000 and the flight dynamics are pretty well on according to real pilots who have operated a TBM 850

Packard Bell i11....64gb ram....1tb SSD....Nvidia 99000 4tb......

400watt corsair......Windows ME 64.

 

What on earth are you running there ??

 

Packard Bell i11 ??

 

64gb ram  !!!

 

Nvidia 99000   ??    ( Nvidia 9900 ?)

 

Windows ME 64 ??  (ME ?? )

 

I would guess he is looking for something low level for sight seeing GA flights so 400kph means a chunk more the 200kts. Lancair Legacy is a great aircraft but isn´t quite that fast at low level.

 

Why don´t you pretend you got a bit extra cash and buy the Lotussim L39. Plenty private owners, not actually that fast and great fun!

At high power settings the Legacy will do 210-215 indicated. I'm not sure on the knots to kph conversion but 215 KIAS is extremely fast for a piston single.

 

Also, when manufacturers write about a planes performance and mention speed it's in regards to True Air Speed. They'll usually boast about a certain speed at a certain altitude... The most efficient altitude for max speed makes nice stats.

No.  True airspeed is just that - TRUE.  It is the actual speed at which you're moving relative to the airmass you're in.  At sea level and standard conditions, IAS (well, actually calibrated airspeed) = TAS , but as you go higher, the gap grows.

 

There's no "fudge-factor", and the number can be calculated precisely from IAS if you know temperature and pressure.  You can also approximate TAS by adding @2% per 1000' of altitude to your IAS.  You can see what a difference this starts to make, as at FL200, for example, TAS is 40% faster than IAS.

 

Scott

 

Ah - now that explanation makes sense!

 

As the pressure on the fuselage is the in-flight measurement, whether at sea-level or FL200, the reduced density at FL200 means the aircraft is moving faster to yield the same IAS, i.e., pressure on the fuselage.

 

Yes?

YES  !    :yahoo:

 

 

Flights too long, and you are getting bored ?

 

Hi Geoff, 

 

Bored? Well, yeah, sort of. I am recreating a friend's cross-country trip that he and his wife did over the span of 55 days earlier this year, but instead of driving I am flying, using the airports "less traveled". Has been great fun planning it, and execution for the most part is a gas (until my d3d11.dll failure shits on me in-flight). However, there are parts of middle America, particularly western Missouri and almost all of Kansas,that are about as much fun as flying a billiard table...    

 

I mess with the weather (a nice brewing storm) and time (at dawn/dusk) to keep it interesting, but man, there is a lot of nothing in middle 'Murica!

An aircraft doing 200kts at sea level shows 200kts on the air speed indicator.  The pitot tube that converts the pressure of the air pushing against it feels 200kts.

 

At altitude, the aircraft is still doing 200kts, but the air is less dense, so the pitot tube doesn´t feel as much air due to this, so it basically shows what it "feels", which would maybe be around 150kts.  So this is a false reading.  The true airspeed is 200kts and can be calculated as mentioned.