Originally Posted by Sean
...I did some experimenting with climbing out at Vx and Vy, and surprisingly enough the differences were not too great in terms of altitude gained vs time. At 50 seconds with Vy I made it to 600 feet, 500 with Vx.
Sean, the whole "Vy versus Vx" question can be answered by simple physics, no analysis is needed. The math goes like this:
You have three possible sources of energy in your aircraft.
1) Kinetic energy (airspeed)
2) Potential energy (altitude beneath you)
3) The engine
If you lose the engine, all you have left is whatever kinetic and potential energy you happen to have at the moment of the engine failure. It is clear from your own independent data collection that climbing at Vy not only accumulates more potential energy in a given period of time, but as an added bonus, it also leaves you with more kinetic energy (a higher airspeed) at the moment the engine fails.
Although it is not directly comparable, observe what large transport aircraft (Boeings, Airbus products) do when they take off: They carry out the initial portion of their climb at what is effectivly Vy (in that class of aircraft, it is called V2, but basically, V2 is Vyse, which is conceptually comparable to Vy in a single).
Michael