The Irvine is a 2 Stroke. While it (0.72) would fly the UCD (60) the performance would not be in keeping with the intent of the design. I own several Irvine engines. All are quite content with large props for the size of the engines. Even though it is larger than the recommended engines for the smaller UCD if throttle management is used it should be a good combination since the Irvines are quite light. The 72 is made in a 60 size case so fit shouldn't be an issue.

This recommendation is made assuming the engine is already in the stable. If not then go with an engine in the recommended range as per the kit MFG.

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