Nice work, Fred!
Gonna start putting my AW P-51 together next week. The 4-blade looks great, but do you still havethe sameair-braking characteristic with 23" of pitch as you did on the last flight? It would seem that the braking effect would get worse with the lower pitch setting (area rule). Have you looked into J'TEC builiding a new muffler for your DA-85, similar to thewraparoundthat they sell for the DA-50? It might provide a more streamlined fit.
Keep us posted...and CONGRATS on the successful maiden!