The Piper Arrow's model is PA-28R-201. At first, I thought that 201 means horsepower but the Arrow's HP is 200 so I figured that's not the case. What does it stand for?
The number notes the model
PA-28R-180 180bhp Cherokee Arrow with the ‘Hershey Bar’ wing.
PA-28R-200 200bhp Arrow II with the lengthened fuselage.
PA-28R-201 200bhp Arrow III with the tapered wing.
PA-28RT-201 200bhp Arrow IV with the tapered wing and T tail.
PA-28RT-201T Turbocharged Arrow IV.
The Arrow III was introduced in 1977 with the tapered wing and larger stabilator. This improved low speed handling characteristics and increased the total fuel capacity from 50 to 77 gallons.