The turbonormalized Cirrus SR22TN has efficient climb performance that out maneuvers the normally aspirated SR22 on three factors:
- Time in Climb
- Downrange Distance
- Fuel Economy
Triple Threat Climb Performance
In practical terms, the turbocharged Cirrus can reach 16,000 feet in half the time, with greater downrange distance, and on less fuel than the normally aspirated Cirrus SR22 NA (see appendix for details).
Time in Climb Example: SR22TN vs SR22 NA
|SR22 NA||97 ~||16,000||25.79||8.48|
How much more time-in-climb does a normally aspirated Cirrus SR22 need? It takes almost twice the time to reach 16,000 feet.
The normally aspirated SR22 pilot must adjust fuel mixture throughout the climb, per the Pilot Operating Handbook, to meet the fuel flow numbers listed. This assumes the pilot will handle the fuel mixture workload task without distraction; otherwise, time in climb and fuel consumption will increase.
Usually, the normally aspirated SR22 will not maintain its best climb rate. The pilot will lower the nose to improve forward airspeed and engine cooling, which adds to the time-in-climb and fuel consumed.
Passing 6,000 feet the power difference is noticeable and at 16,000 feet the normally aspirated engine has only a portion of its power remaining. A setting of 2,500 RPM produces just 55% power, and a True Airspeed (TAS) of 168 knots (SR22, POH, Section 5-24, Revision 2). With the same RPM setting, the turbonormalized Cirrus delivers 25 knots more on TAS.
Choosing higher altitudes in the normally aspirated Cirrus means compromising on available engine power and enduring a longer time in climb. The maximum SR22 NA altitude is 17,500 feet.
The turbonormalized SR22TN engine power is unrestricted all the way up to 25,000 feet, and will expedite en route climbs for faster cross-country flights. The turbocharged design reduces workload because only one mixture setting is needed for efficient performance throughout the entire climb.
Initially, I considered a normally aspirated pre-owned Cirrus because I thought it held performance close to the turbo. But it doesn’t.
Cirrus SR22 NA, Example en route climb, 3400 lbs
|Press Alt||KIAS||Temp. ~C||FPM||Minutes||Gal. Used||GPH|
Cirrus SR22 NA, POH, Rate of Climb Chart, 3400 lbs
|Press Alt.||Climb Spd.||Rate of Climb – Feet per Minute (Temp. ~C)|
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