Gross weight increase

[mogulmark@msn.com]

Can someone lend info as to the availabilty of getting a gross weight increase for a 1963 150C that has a 0-320-E2D installed on it. The STC does not increase the GW and says you must use factory specs and operating envelopes. current GW is 1500# and in 64 the GW went to 1600# I called Cessna and according to them nothing structurally is different just was a marketing move to up the GW to 1600. Would like to up GW to the 1760#.

 

[tinerj]

Can someone lend info as to the availabilty of getting a gross weight increase for a 1963 150C that has a 0-320-E2D installed on it. The STC does not increase the GW and says you must use factory specs and operating envelopes. current GW is 1500# and in 64 the GW went to 1600# I called Cessna and according to them nothing structurally is different just was a marketing move to up the GW to 1600. Would like to up GW to the 1760#.

Planes can't read.

 

[Pilawt]

I called Cessna and according to them nothing structurally is different just was a marketing move to up the GW to 1600.

I doubt that the person you talked to on the phone was around in 1964. But Bill Thompson was, as Cessna's Manager of Flight Test and Aeronautics. He wrote about the development of the 1964 "Omni-Vision" 150D from the earlier fastback 150s:

"The structures group was certain that a sizeable empty weight increase would be in the cards along with a drastic change in the natural frequency of the empennage with such a slender tailcone. The latter problem could possibly require much heavier elevator and rudder mass balance weights to preclude airframe flutter in dives. In fact, all of these fears were realized, for the gross weight had to be increased from 1500 to 1600 pounds, and this, in turn, reduced the already-marginal climb performance [...]. The author recalls numerous delays in opening up the speed envelope while flutter analysts worked around the clock trying to qualify the airplane for a comfortable flutter-speed margin above the 162 mph red line speed."
​

Your 150C doesn't have balanced control surfaces on the tail, and weight distribution is somewhat different, so aerodynamically it is different.

 

[jimmyjack]

When I asked this same question about my 150noletter I was told you're stuck at 1500LB. Enjoy your single seater.

 

[Tom-D]

Can someone lend info as to the availabilty of getting a gross weight increase for a 1963 150C that has a 0-320-E2D installed on it. The STC does not increase the GW and says you must use factory specs and operating envelopes. current GW is 1500# and in 64 the GW went to 1600# I called Cessna and according to them nothing structurally is different just was a marketing move to up the GW to 1600. Would like to up GW to the 1760#.

Have your A&P-IA ask for a field approval, then be prepared to do the flight testing after the DER does the structural engineering to state the fuselage /wing will carry it.

 

[docmirror]

I will opine that it will never happen. I have a 22% increase in HP in my plane over factory, and I'm still limited to the original book gross weight restriction.

 

[MauleSkinner]

Have your A&P-IA ask for a field approval, then be prepared to do the flight testing after the DER does the structural engineering to state the fuselage /wing will carry it.

...and I hope you like to do spins. A friend of mine holds an STC for Cessna 170s. The FAA made him do spins at various weights anywhere from out of CG limits forward to out of CG limits aft. LOTS of spins.