Cirrus Performance Info

Guest Discussion
1

I am looking for the max speed for the Cirrus SR-20…cruise speed info is on the website but not max speed.

Thanks.

2

If you believe the POH, max speed for level flight is 164 KTAS at 2000 feet ISA (95% power and 15 GPH). They don’t show it but the lower you fly the faster you will go. If you don’t mind flying in ground effect you should be really fast until you hit something.

3

Thanks, I guess you’d need to keep your eyes peeled flying like that!

Would you happen to know the cruise range (75% @ sea level) for the same aircraft, they quote the max as 800 nm on the performance info on the site, but not the cruise.

I appreciate the help.

4

Shirley:

The POHs for both the SR20 and SR22 are available here in the http://www.cirruspilots.org/members/docs/index.html>Documents of the COPA web site, as well as on the Cirrus Design site. You should be able to get all the performance information you need in the POHs.

5

Would you happen to know the cruise range (75% @ sea level) for the same aircraft, they quote the max as 800 nm on the performance info on the site, but not the cruise.

The POH shows 609 for 2000 feet but according to my calculations 561 is closer (1 hour reserve best power), if you lean at best economy (something the factory indicated you should not do) you would get 652 nautical miles.

6

Shirley,
The cruise and range data for any aircraft are really very complex. In general the maximum true airspeed for any power setting is at the highest altitude at which that power setting can be maintained. So for 100 % power the highest speed would be at sea level on a standard day. Once you climb the air is “thinner” and the maximum power your engine can produce is less and less as you go higher. Since you can maintain 75% up to about 8000 feet the max speed at 75% would be at that altitude etc.
For range, in general you will do much better at lower power settings (usually down to about 50% power) because the drop in speed is more than offset by the drop in fuel consumption with the result that you can maintain a slightly lower speed for a much longer time resulting in increased range. Below about 50% power the drop in speed is too much to be offset by the decreased fuel consumption. Furthermore by leaning the mixture (and this IS approved in the POH) you can extend range even further.
But as a rule of thumb, neglecting winds aloft, the maximum speed and the maximum range at any given power setting will be at the highest altitude at which the power can be maintained. This true for any non turbocharged airplane.
Hope this is useful.
Jerry

7

Thanks allot…I downloaded the POH and I have everything I need.

8

Thank so for the detailed explanation, I appreciate the information.