Getting the book numbers

[Apache123]

I'm just curious how many of you get the book numbers for cruise flight (in GA aircraft).

The POH states my PA-23-150 can theoretically get 172MPH (about 150kts), so far I've only seen this while practicing emergency descents

 

[Tony_Scarpelli]

My Cherokee got exactly on the numbers across the board. But that doesn't account for the speed mods which were supposed to make it go 7 knots faster.

On my Turbo Comanche, It does within 2 knots at 8000' 153 kts but that's not bad for a 62, huh? I've been told the Turbo when not in use still lowers my normal aspirated speeds down low.

The turbo does gives me +20 knots on top of the book numbers 175 kts at 11,000' but the turbo doesn't give me 25" MP through 20,000' like it says it does. If it did I might get the 190 knots promised by the STC.

 

[dukeblue219]

I actually took some time to log the cruise performance of my Tiger on my last cross country, and came up with the following comparison to the POH:

Power: 75%
Pressure Alt: 7000
Temp: ISA + 5degC (book numbers are from ISA)

Book Speed: 131 KTAS
Actual Speed: 134 KTAS

Book Fuel: 11.5gph
Actual Fuel at 50* ROP: 9.3gph


So, I'm seeing a hair over book speed at 19.2% less fuel burn while operating about 300 pounds under gross.

 

[MachFly]

In the TwinStar I get almost exactly what the book says.

 

[wabower]

Most of the book numbers that have been published since the new POH format became mandatory seem to be pretty close. Older planes, not so much although some were better than others. I've owned 2 172's, 2 Bo's, one Mooney, several Comanches, 180's and 210s, along with some bigger airplanes. All were close enough to book that the differences could be attributed to instrument calibration or installation.

 

[dukeblue219]

I do think it's worth differentiating between "book" numbers (which for my plane are accurate-to-conservative) and "marketing" numbers. The current owner of the AG5B type cert, TrueFlight, lists "Speed (mid-weight cruise)" as 143 KTAS which I highly doubt is possible at any reasonable operation.

 

[JHW]

I'm just curious how many of you get the book numbers for cruise flight (in GA aircraft).

The POH states my PA-23-150 can theoretically get 172MPH (about 150kts), so far I've only seen this while practicing emergency descents

if you think yours is funny, look at some of the aztec piper marketing numbers

 

[LDJones]

I'm just curious how many of you get the book numbers for cruise flight (in GA aircraft).

The POH states my PA-23-150 can theoretically get 172MPH (about 150kts), so far I've only seen this while practicing emergency descents

The Geronimo I fly has all the aerodynamic improvements and two 180 hp engines and I plan for 145 kts.

I think they were pretty optimistic in their POH!

 

[denverpilot]

We're within "instrument tolerances" on ours if you assume the stall fences knock off a few knots. Robertson didn't change the book numbers from Cessna in their STC, but they stuck stall fences on top of both wings. I think we're also ever so slightly out of rig. And I can imagine with all the bell cranks and goofiness attached to the ailerons, that re-rigging the Robertson is an all day chore.