Username Protected wrote:
The 26” limitation on takeoff was necessary since Colemill did not do the expensive flight testing needed to rewrite the performance data in the POH.
The performance is not the issue, they could have simply stated "no worse than book" and left it at that like many other engine STCs. The FAA doesn't require new performance figures as long as you meet or exceed the stock performance.
The issue was elevating Vmc. If you have higher power, Vmc goes up. Elevated Vmc would trigger some certification rules that limit allowed Vmc values.
Easy way around that, just publish a limit that keeps Vmc the same.
Mike C.