I have been flying with Prop #7 for some time now and it is absolutely my favorite prop. Overall it is a great compromise. Below you will see the data I provided to Catto. Tests were all done with fuel fuel on take off.
- Qualitatively it sounds quieter than previous test props.
- It grabs nicely about half way down the takeoff roll. It reduced takeoff roll from 990-1,000 ft to 900-910 ft.
- Good glide distance demonstrated during simulated engine out. The aircraft could glide further than with prop 5. Qualitatively it seemed to contribute less to the total drag of the aircraft. It was similar in performance to prop 4 during this test.
- No negative impact to the CHTs or oil cooling observed (did not have the issue as prop 4 did with cooling impacts).
- Climb performance improved. I was able to climb at 115-120 kts vice my standard 125-130 kts without slowing down my preferred RPM.
- At 8,000 ft DA and 2,700 RPM it is the fastest prop thus far cruising at 182 KTAS. Previous test props demonstrated 176 KTAS (prop 3) - 178 KTAS (prop 5) at the same test conditions.
- At 12,500 ft DA and 2,700 RPM it is comparable at 180 KTAS to prop 5 (179 KTAS).
- It was very difficult to slow down the aircraft. It was similar in performance to prop 4.
- At 8,000 ft DA and 2,760 RPM (WOT) it is comparable to prop 3 at 187 KTAS but 3 kts slower than prop 4 (190 KTAS) and 5 kts slower than prop 5 (192 KTAS in non-race configuration).
- This is a good overall prop. It has the best take off performance and cruise performance at 8,000 DA and 2,700 RPMS thus far. It is not the prop for racing or flying a lot of formation flights. The majority of the RV community would find this prop to be a good compromise throughout the flight envelope.
- It will also allow the pilot to use the max out of the engine horse power without feeling like he/she will exceed the 2700 rpm engine limit cruising at altitude.
Prop #8 is a 3 bladed derivative with Nickle leading edges and clear tape. We chose to go with the mate paint on the prop and spinner. The combination looks cool. This is a 64X78. If you want to see the prop, it will be on my plane at OSH.
Talking about spinners. I have been struggling to figure out a way to use my 14 lb crush plate with the new Catto spinner. We ended up boring a hole 1/4 inch deep on the crush plate with the corresponding diameter of the spinner dowel. We then measured the spinner dowel and cut the length as required. The spinner dowel now sits inside the crush plate in a similar manner it does inside the prop. The nice thing was that minimum weight was removed from the crush plate. Data will take a while to collect but will keep you guys informed.