Climb Rate

[Flying Bozo]

I was talking to a person who was looking at a light sport for his future and he took a ride in a Piper Sport. He said it was a real slow climber and asked what it would do when it was hot outside. The person giving him the demo didn't have an answer. I know they are not called that any more but they are still in production under another name. The specs call out a 1200 fpm rate of climb for that plane and the CTSW is called out as 900 FPM.

I would like to hear some feedback on these numbers because I can't believe that the Piper can do 1200 even not fully loaded. Here at about 4000 MSL I can see 600 or maybe a little more fully loaded in my CTSW and I suppose that if I were at sea level it might go to the 960 as specified.

Some simple calculations tell me that it would take 48 of the available horsepower to lift 1320 pounds up at a rate of 1200 feet per minute. That does not take into account the drag on the airframe from the two sources of drag which I roughly calculate to be about 88 pounds of pull needed by the propeller to fly along at best L/D. The L/D for the CT is about 15 to 1 or so and I don't think it could be any better for the Piper Sport.

So this is where I would like to have some feedback. If I give the prop an 80% efficiency then we are only having available 80 HP to do the work and 48 is used up making the airplane go up at 1200 FPM. that only leaves 32 HP to drag it along. Hmm is there something that I am missing or is the 1200 FPM a greatly exaggerated number for the Piper?

Larry

[Jim]

My CT climbs the same as yours. I vote greatly exaggerated.

[Flying Bozo]

I agree with your replys. The quoted figures are supposed to be at gross weight of 1320 and it appears to me that the CTSW comes pretty close to doing the numbers that they say...i.e. 960 FPM although I have never been at sea level with it. Ans yes Roger, I was astounded recently when I only had a little gas in it and myself (220) with the takeoff and climb performance.

Larry

[Flying Bozo]

By the way, the Technam Sierra which looks much like the Piper Sport and has the same Rotax in it calls out a 750 FPM rate of climb. Go figure!!

Larry

[Jacques]

I have two Tecnam Sierra here at my airport , ( both with 100 hp) and my 80 hp CT outperform them on climb with the same weight ... must be pilot technique

[Flying Bozo]

Jaques, that sounds about right. The Technam Sierra calls for 750 FPM and the CT calls for 960 FPM. I don't know what would be the difference except the airfoil is so much cleaner on the CT with no rivits and also being true to shape.

Larry

[rookie]

I'm 143# with a rock in my pocket and normally fly with 1/2 tanks. We typically have low DA, often negative. When I first got my LPA I would climb out at 1100/1200 FPM indicated, just because I could . I don't anymore; after hearing horror stories about cracked crankcases due to over torquing I now go out at 750/800 FPM. Also I'm not sure how accurate these indicated numbers are since when I flew to AZ last fall I noted that even at higher DA I could still climb out normally.

 

rookie,

[Jim Meade]

I did a quick google search on Rotax 912 cranckase over torque and got no hits. Can someone discuss this issue, please? And relate it to the rate of climb?

[N89WD]

The other day OAT was 26F. My field elevation is 6210 Myself (195) my Dad (205) and 20 gal of fuel we climed at 700fpm @vy with 0 deg flaps up to 11,500'. I belive the DA was 3600' or so. Not too bad at MTOW.

[S4Flier]

Gotta love winter time for performance.  Climbed out this morning at 1000fpm at 95 kts IAS and 40F.