Real Cruise Performance

[flyguy]

Has anyone done a cruise check with a GPS, as in 2 direction average to correct for wind? My input is BC12D-85, calm day 95 north, 99 south, average 97 statute at 2300 rpm. Anyone else? Seems a little slow for an 85, but then the airplane is optimized for 2150 with a 65 correct? (actually I suspect it was optimized for climb and let cruise fall where it may.)
Darryl

[crispy critter]

Re: Real Cruise Performance

You may be able to improve your cruise a little by raising the trailing edge of your wings,however you will loose a little bit of climb performance when you do.Are those speed numbers from your GPS in mph or knots?

[dennispip]

Re: Real Cruise Performance

I think your cruise speed is about right. In my F21B (118 Ponies) I cruise right around 100 MPH at 2300. I can go 115 MPH at the top of the green on the tach @ 2600, but the plane sounds and feels best at 2400 and that gives about 105. If I pull it back to 2100, I'm down to about 90. These are GPS speeds.

From what I've read, the F22 which has 180 HP, will max out at only 125 MPH. These planes have draggy airframes and the extra HP doesn't translate into that much speed differential. Where the HP does show up in a big way is in take off performance, climb, and payload. I'm sure you are able to get out of your field in these 90 plus days much better than the 65's and your climb rate is improved as well.

[Yellow Duck]

Re: Real Cruise Performance

The "Yellow Duck" with 65 hp cruises between 95-100 @2100 RPM and gets between 100-105 @2300 RPM. This is with a 74 x 41 metal prop.

To increase your speed increase your pitch. ie: 41 to 45.


The reverse is true; to increase your climb, flattenout the pitch. ie: 45 to 41.

The flatter your pitch the higher your RPM the better climb and slower in cruise. And of course the reverse is true for speed. Up to a point of course.

[flathorn]

Re: Real Cruise Performance

I only see 100mph on a good day anymore - and that's with an 0-200 on an F19.
Too much tire hanging down (26") and the baby Borer climb prop. If I thought of taking an extended flying trip, I'd have to go back to my 8.50's and cruise prop... (I keep them around just in case).
Last week, I went flying with some other planes and the other T-Craft in the group (with the cruise prop) left me in the dust. I'd forgot how fast they are clean. But of course my comfort level was higher on the morraine landing/takeoff than his, but not in the air. I guess it really is about trade-offs.

Kathy

[jgerard]

Re: Real Cruise Performance

Mac 74-43 on a FRESH !! MOH A65 gets me 2300 static ( stock breaks hold her just fine) and 2600 level flight. Top speed was 115mph indicated 200' msl and OAT 65 deg. normal cruize at 2300 rpm was 100 mph.


Jason
N43643

[dennispip]

Re: Real Cruise Performance

Those are really good numbers! Did you check your speeds with GPS? I think you will have many years on good service from your powerplant upgrade. Enjoy!

[jgerard]

Re: Real Cruise Performance

I will soon Dennis. I was flying her with the top of the dash still off so I could inspect the new oil line behind the dash in flight. My GPS pilot III is usually mounted front and center during testing but this time I was more interested in finding leaks than ground speed. I'll have her back to normal soon and let everyone know the final numbers.

Jason
N43643