Airshares SR-20

wrote in message
...
According to the Cirrus website, the SR-20 cruises at 156 kts at 75%
power.

What's the fuel flow at 75% power? For a 200 hp engine, my guess is that
it's significantly more than 9 gph. Or conversely, it seems likely that the
9 gph isn't 75% cruise.

If I bought an SR-20 and it only gave me 130 kts at best cruise
performance,
I'd demand my money back!

Art didn't say 130 knots was his "best cruise performance". He said that's
what he gets at 9 gph. I assume he used that figure because that's close to
the fuel flow in a Cessna at normal cruise settings (with a 160 hp engine),
and so gives a rough apples-to-apples comparison between the airplanes.

Pete

On 2-Dec-2003, "Peter Duniho" wrote:

What's the fuel flow at 75% power? For a 200 hp engine, my guess is that
it's significantly more than 9 gph. Or conversely, it seems likely that
the 9 gph isn't 75% cruise.

Art didn't say 130 knots was his "best cruise performance". He said
that's what he gets at 9 gph. I assume he used that figure because that's
close
to the fuel flow in a Cessna at normal cruise settings (with a 160 hp
engine), and so gives a rough apples-to-apples comparison between the
airplanes.


In my Arrow, which like the SR-20 has a normally aspirated 200 hp engine, I
can true 135 kts at 65% with a fuel flow of around 9.4 gph. 9 gph would
probably be about 60%, give or take a little. Since for a given airframe
airspeed varies as the cube root of applied power, assuming equal propeller
efficiency (and that's a good assumption with a constant speed prop) 130 kts
at 60% would correspond to 140 kts at 75%, which, not surprisingly, is
almost exactly what I get in the Arrow. (141 kts to be precise.) That is
still a far cry from the 156 kt "book" 75% cruise speed for the SR-20.
--
-Elliott Drucker

wrote in message
...
[...] 130 kts
at 60% would correspond to 140 kts at 75%, which, not surprisingly, is
almost exactly what I get in the Arrow. (141 kts to be precise.) That is
still a far cry from the 156 kt "book" 75% cruise speed for the SR-20.

That's a number that a) is a lot closer to the published value than the one
you were originally complaining about, and b) is extrapolated by you, not an
actual reported value. You'll notice another SR20 owner reported nearly 150
knots on 10.6 gph. A variety of other differences could easily account for
the rest of the airspeed variability.

Pete

My fuel flow, at 65% power, for my 200 HP T-Arrow is about 12 gph , but at 65%
power I cruise at 150 KTAS (or better - I plan for 150 tho) and can fly non-stop
for 700 NM - But this is also flying at 8000-13000 ft.

Jeff
http://www.turboarrow3.com

Peter Duniho wrote:


What's the fuel flow at 75% power? For a 200 hp engine, my guess is that
it's significantly more than 9 gph. Or conversely, it seems likely that the
9 gph isn't 75% cruise.

If I bought an SR-20 and it only gave me 130 kts at best cruise
performance,
I'd demand my money back!

Art didn't say 130 knots was his "best cruise performance". He said that's
what he gets at 9 gph. I assume he used that figure because that's close to
the fuel flow in a Cessna at normal cruise settings (with a 160 hp engine),
and so gives a rough apples-to-apples comparison between the airplanes.

Pete

"Jeff" wrote in message
...
My fuel flow, at 65% power, for my 200 HP T-Arrow is about 12 gph , but at
65%
power I cruise at 150 KTAS (or better - I plan for 150 tho) and can fly
non-stop
for 700 NM - But this is also flying at 8000-13000 ft.

First of all, 12 gph for 130 hp sounds to me like a lot of gas. I can get
the fuel flow on my 270 hp engine down to 12 gph at around the same power
setting (60-65%). You might want to double-check your engine gauges.

Secondly, turbocharging isn't a fair comparison (you as much said this),
since you get to enjoy full power operations at the higher altitudes where
true airspeed increases.

Pete

I have a shadin fuel flow monitor, it is pretty consistant with the airplanes
fuel flow gauge. I can lean it out more but that is best power setting. since I
only fly at 65% power, I dont want to lose what I have by skimping on the fuel
mixture. Plus this is a power setting, its not 65% due to altitude or fuel flow,
I set power (2400 RPM / 30" MP) for 65% then lean for best power.

the engine in the t-arrow is a cont. 6 cylinder, fuel injected, the normally
aspirated one is a 4 cylinder lycoming. why piper stopped making the T-arrow I
dont know, I think its alot better the the normally aspirated one (I have fown
both). But if it came down to buying a new airplane, An arrow or a SR20, the
arrow new is 271k (standard listing) - I think the sr20 would win out. Piper is
going to have to do something or cirrus is going to put alot of hurt on them and
other companies.


Peter Duniho wrote:

"Jeff" wrote in message
...
My fuel flow, at 65% power, for my 200 HP T-Arrow is about 12 gph , but at
65%
power I cruise at 150 KTAS (or better - I plan for 150 tho) and can fly
non-stop
for 700 NM - But this is also flying at 8000-13000 ft.

First of all, 12 gph for 130 hp sounds to me like a lot of gas. I can get
the fuel flow on my 270 hp engine down to 12 gph at around the same power
setting (60-65%). You might want to double-check your engine gauges.

Secondly, turbocharging isn't a fair comparison (you as much said this),
since you get to enjoy full power operations at the higher altitudes where
true airspeed increases.

Pete