db1yg
Well Known Member
Latest Catto Design
I recently had the opportunity to test some of Craig Catto?s latest designs on my 2006 RV9a/180. Since I had been talking to him about my need for more pitch and the fact that I had some prop testing experience with him, he shipped me two prototypes (a 68x76 and a 68x75) of his latest (March 2014) three bladed carbon fiber over laminate for testing head to head with my 2005 vintage fiberglass over laminate three blade. This new design is probably close to that recently tested by Axel on his RV4/160. After Axel?s tests, I understand that Craig mounted it on his personal RV6/160 and refined the design further, then made the modifications necessary to match it to a 180 hp RV. The following is some of the data that I provided Craig after around 8 hrs flying behind these two propellers.
BTW, I apologize for the formatting issues on the raw data. I had the data spread nicely under the column heads but my word processing system does not play nicely with VAF's software--however, I think you will follow!
2005 Catto 3 Blade vs. 2014 Catto 3 Blade Design
The following comparison testing on the latest Catto design carbon fiber over wood 3 blade vs. the older design fiber glass over wood 3 blade was done from KPRC (Prescott, AZ) from a field elevation of 5050 ft. All power data was recorded by an Advanced Flight Systems AF-2500 Electronic Engine Management System while all flight data was taken from a Dynon D10a Electronic Flight Information System. The true airspeed and density altitude data is from the Dynon which has been certified for IFR flight and the static system has been calibrated and verified accurate to within 1 kt below 160 kts and 1.5 kts above 160 kts. The posted data has been corrected for the measured static system error. All data was based on 3 runs averaged. If a run was significantly different or encountered other than smooth air, it was discarded and an additional flight was conducted.
The aircraft on which the props were tested is a Van?s RV9a equipped with an Eci I0360/180hp (stock compression) engine fired by a Lightspeed Plasma III electronic ignition on one side and a stock Slick magneto on the other. The FI system is from Air Flow Performance. The aircraft has a Sam James cowl/plenum --otherwise the airframe is stock with the exception of some detail aerodynamic clean up.
2005 Catto 2014 Catto 2014 Catto
(66x76) (68x75) (68x76)
I. Prior to Take-off
F/P Run up Rich (rpm) 2200 2200 2160
F/P Run up Leaned 2240 2245 2210
II. Take Off
RPM at Lift Off 2210 2190 2165
Speed at Lift Off (kts) 75 75 75
III. Climb Out 110 kts from 7 to 8000 Density Alt
RPM (ave) 2425 2295 2285
Climb Rate (FPM) 1400 1300 1150
IV. Cruise at 9k Density Altitude
MP/GPH----RPM/KTAS by Prop
2005 (66x76) 2014 (68x75) 2014 (68x76)
19/8.4 2540/159 2450/159.5 2383/158
20/9.0 2600/163.5 2520/165 2457/163
21/9.9 2660/167.5 2590/170 2530/168.5
22/10.5 2730/173.5 2660/176.5 2600/174
V. Wide Open Throttle Run 9K Density
I addition to the above cruise tests, I did WOT runs on both propellers. The wot speed at 9k density went up by 2+ kts while the rpm went down when compared to the 2005 prop.
Notes/Comments:
1. Cruise power was set by leaning to peak power/rpm with the 2005 prop and then using the same fuel flow and mp setting on the 2014 prop tests. The objective was to produce equal or higher speed on lower rpm with the same mp and ff--which both the 68x76 and the 68x75 accomplished.
2. Cruise data was captured at 9k density altitude in smooth air with the auto pilot/altitude hold engaged. Rough air data was discarded.
3. Multiple runs were made at all settings for both props, statistically inconsistent data discarded, and the 3 most consistent runs on each prop were averaged.
4. All tests were initiated with full fuel and solo which results in the cg being forward of the range mid point.
5. The 2005 fiberglass over laminate Catto 3 blade (66x76) weighed in at 17 lbs while the 2014 carbon fiber over laminate Catto 3 blade propellers both weighed in at 12.4 lbs.
6. The new design is noticeably thinner than the old throughout the blade length--especially at the blade root. The aft side of the blade root is somewhat concave. The hub is 3.75 inches thick while the hub on the 2005 unit is 4.25 inches thick.
7. Both props were incredibly smooth across the entire rpm range.
8. The 68x75 was flown from Prescott (ele 5050 ft) to Lake Havasu City (ele 870 ft) where take off and climb performance picked up significantly when compared to the high altitude take off and climb data from Prescott. However, how can you complain about 1300 fpm from 7 to 8k ft at 110 kts--we RV drivers are a spoiled lot!!
9. I may also be testing a 68x74 of the same design--if so I will post the comparatives.
Conclusion: This design exceeded my hopes----equal speed at low power cruise, better speed at mid to high power cruise, and all at a lower rpm. The 76? was clearly too much pitch for my stock 180hp James equipped 9a--I will be going with either a 74? or a 75?. Craig tells me that this design will be available with the nickel leading edge.
I also have some pics of the new design mounted on 9db if anyone has any interest.
Cheers,
db
I recently had the opportunity to test some of Craig Catto?s latest designs on my 2006 RV9a/180. Since I had been talking to him about my need for more pitch and the fact that I had some prop testing experience with him, he shipped me two prototypes (a 68x76 and a 68x75) of his latest (March 2014) three bladed carbon fiber over laminate for testing head to head with my 2005 vintage fiberglass over laminate three blade. This new design is probably close to that recently tested by Axel on his RV4/160. After Axel?s tests, I understand that Craig mounted it on his personal RV6/160 and refined the design further, then made the modifications necessary to match it to a 180 hp RV. The following is some of the data that I provided Craig after around 8 hrs flying behind these two propellers.
BTW, I apologize for the formatting issues on the raw data. I had the data spread nicely under the column heads but my word processing system does not play nicely with VAF's software--however, I think you will follow!
2005 Catto 3 Blade vs. 2014 Catto 3 Blade Design
The following comparison testing on the latest Catto design carbon fiber over wood 3 blade vs. the older design fiber glass over wood 3 blade was done from KPRC (Prescott, AZ) from a field elevation of 5050 ft. All power data was recorded by an Advanced Flight Systems AF-2500 Electronic Engine Management System while all flight data was taken from a Dynon D10a Electronic Flight Information System. The true airspeed and density altitude data is from the Dynon which has been certified for IFR flight and the static system has been calibrated and verified accurate to within 1 kt below 160 kts and 1.5 kts above 160 kts. The posted data has been corrected for the measured static system error. All data was based on 3 runs averaged. If a run was significantly different or encountered other than smooth air, it was discarded and an additional flight was conducted.
The aircraft on which the props were tested is a Van?s RV9a equipped with an Eci I0360/180hp (stock compression) engine fired by a Lightspeed Plasma III electronic ignition on one side and a stock Slick magneto on the other. The FI system is from Air Flow Performance. The aircraft has a Sam James cowl/plenum --otherwise the airframe is stock with the exception of some detail aerodynamic clean up.
2005 Catto 2014 Catto 2014 Catto
(66x76) (68x75) (68x76)
I. Prior to Take-off
F/P Run up Rich (rpm) 2200 2200 2160
F/P Run up Leaned 2240 2245 2210
II. Take Off
RPM at Lift Off 2210 2190 2165
Speed at Lift Off (kts) 75 75 75
III. Climb Out 110 kts from 7 to 8000 Density Alt
RPM (ave) 2425 2295 2285
Climb Rate (FPM) 1400 1300 1150
IV. Cruise at 9k Density Altitude
MP/GPH----RPM/KTAS by Prop
2005 (66x76) 2014 (68x75) 2014 (68x76)
19/8.4 2540/159 2450/159.5 2383/158
20/9.0 2600/163.5 2520/165 2457/163
21/9.9 2660/167.5 2590/170 2530/168.5
22/10.5 2730/173.5 2660/176.5 2600/174
V. Wide Open Throttle Run 9K Density
I addition to the above cruise tests, I did WOT runs on both propellers. The wot speed at 9k density went up by 2+ kts while the rpm went down when compared to the 2005 prop.
Notes/Comments:
1. Cruise power was set by leaning to peak power/rpm with the 2005 prop and then using the same fuel flow and mp setting on the 2014 prop tests. The objective was to produce equal or higher speed on lower rpm with the same mp and ff--which both the 68x76 and the 68x75 accomplished.
2. Cruise data was captured at 9k density altitude in smooth air with the auto pilot/altitude hold engaged. Rough air data was discarded.
3. Multiple runs were made at all settings for both props, statistically inconsistent data discarded, and the 3 most consistent runs on each prop were averaged.
4. All tests were initiated with full fuel and solo which results in the cg being forward of the range mid point.
5. The 2005 fiberglass over laminate Catto 3 blade (66x76) weighed in at 17 lbs while the 2014 carbon fiber over laminate Catto 3 blade propellers both weighed in at 12.4 lbs.
6. The new design is noticeably thinner than the old throughout the blade length--especially at the blade root. The aft side of the blade root is somewhat concave. The hub is 3.75 inches thick while the hub on the 2005 unit is 4.25 inches thick.
7. Both props were incredibly smooth across the entire rpm range.
8. The 68x75 was flown from Prescott (ele 5050 ft) to Lake Havasu City (ele 870 ft) where take off and climb performance picked up significantly when compared to the high altitude take off and climb data from Prescott. However, how can you complain about 1300 fpm from 7 to 8k ft at 110 kts--we RV drivers are a spoiled lot!!
9. I may also be testing a 68x74 of the same design--if so I will post the comparatives.
Conclusion: This design exceeded my hopes----equal speed at low power cruise, better speed at mid to high power cruise, and all at a lower rpm. The 76? was clearly too much pitch for my stock 180hp James equipped 9a--I will be going with either a 74? or a 75?. Craig tells me that this design will be available with the nickel leading edge.
I also have some pics of the new design mounted on 9db if anyone has any interest.
Cheers,
db
