I try again ! I fully understand you nostalgia, but will anyhow buzz up the discussions with a few facts. 1. A smaller plane with a noisy engine at a high RPM is always thought to be faster than a big, quiet plane with an engine at low RPM. 2. A fast (not very accurate) calculation of prop pitch and RPM reveals the following : A prop with 7" pitch at 15k idicates a speed of 44.5m/s = 160km/h, a prop with 13" pitch at 8k idicates a speed of 44.0m/s = 158km/h. Not that different, huh ! In addition comes the fact that the bigger prop is more efficient and will generate more 'overspeed' due to propeller lift than the smaller one. I did measure the speed of my OS-140RX-FI equiped ZN-line Alliance with a radar-gun during easter, in a shallow dive it was close to 220km/h ! The seemingly low speeds during todays F3A schedules is not due to lower speed of the models, but a result of the flying style that requires throttle management. Then the models is made to be able to fly well at lower speeds. Do not missunderstand me, if you have fun flying a 30+ year old design with a lower power to weigth ratio than todays norm, feel free. The whole ide of this sport is to have fun !