I am surprised that the prop holds up at those rpms. I am sure it is over the chart they give out in the package. ;-) Must be hard to see at those speeds. I have trouble at about 100mph with the little ones. The .09 and .12 may get the best speeds on the little props, I just had a rod get very sloppy quickly on my little AP .15 at only 25,000 rpm and worry about the motor letting go. I guess it is something to laugh about later. They are only $35 after all.