Originally Posted by
oggers
"At the end of the day the FARs of the time said Vc need not be higher than 0.9VH, and it seems that is what Piper did.
It would seem that the majority of manufactures did not and many also provided a good buffer, which is generous of them as Vd is tied to Vc. More understandable in a Husky less so in a commuter.
The Vno of the Archer 3 didn't change from the Archer 1.
Precisely, this is what I mean by a 'reduced' or artificially low Vno.
To my mind if they needed to reduce Vno in order to achieve a higher weight this is not a weaker airframe, it is the same airframe optimised for a different task.
I would say that all the Cherokees share an equivalent task. The heavier ones are now more boxed in on descents.
Also note that the in Rev 44 of the PA-28 TCDS the Archer III was given a Va of 108KCAS, later changed to the 111KCAS at 2550lbs – 89KCAS at 1634lbs we have now (rev. 59). Unclear as to why. It looks like original Hershey bar winged PA-28s use 112KCAS for Va. When the longer winged Archers came out it went down to 110KCAS then 108 with the taper wing, then revised to the range we have now. Also noteworthy is the reduced aileron control surface movement limitations in the taper wing PA-28s even when compared with the long Hershey bar winged Archer. (25/12.5 vs 30/15) The first taper wing aircraft, the 1973/4 PA-28-161 Warriors, had the spar failure issues and early serial numbers that also ended up with reduced aileron control surface movement limits.
I appreciate your thoughts oggers but I think the later heavier Cherokees are an example of an outlier here.