AX-O
Well Known Member
Full disclosure as requested by someone on the forum. I DO NOT work for Catto Props or received any compensation for this test or post. I did purchased a 3-bladed Catto prop at full price for my fastback 4 and I have not been able to fly it yet.
Overall impression:
Large leap in performance improvement over the Sensenich fixed pitched metal prop during formation flight.
Current aircraft configuration:
-RV-4
-Lyc O-320-E2D
-160 HP/ 8.5:1 pistons / Slick mags
-Sensenish 2 bladed, Model 70CM, 70’ diameter, 78” pitch.
-Configuration for most test flights is 32 gal fuel, me (170 lbs) and 15 lbs of baggage. Total aircraft weight approx 1420. CG 71.6 inch.
-Short gear and old style wheel pants.
New prop:
-Catto prop: Next Generation. Length 70 in/Pitch 73
Pilot:
-approx 450 hrs on this particular RV-4
-FFI carded
A few days ago, I performed limited flight testing (7 hrs) for Mr. Catto. I qualitatively evaluated the performance of his prop on my aircraft as compared to the current aircraft configuration. This was not an engineering test as I did not have time to compare aircraft (weight, CG, etc.) and environmental (temp, DA, Alt, etc.) conditions. So you won’t see many performance numbers. This evaluation was an overall eval (pilot impression) at different uncontrolled operating and atmospheric conditions. The mission task I chose for the eval was formation flying as it would provide almost instant feedback when compared to a “stationary” flying aircraft. OATs varied from 95 to 112 deg F, altitude varied from sea level to 3,000 ft MSL, aircraft weight varied from 1100 lbs to max gross.
Engine starts:
The first engine start was eye opening because I did not expect to experience performance differences that early into it. As the first blade turned I could tell the prop had very low inertia. Once the engine started the aircraft launched forward and then rebounded back (a few times). The plane wanted to go flying already. I have not experienced that before with the Sen prop. And yes it was at approx the same RPM as I use normally. Every other start was like that even at idle power. Once I removed the Catto prop and reinstalled my Sen prop that did not happen again. Both props idled at the same rpm however I had to bump up my RPM to approx 900 on the Catto (vice 800 on Sen Prop) for lower engine vibration. I suspect this is due to the low turning inertia generated by the Catto prop. Once at that RPM the prop felt as smooth as my dynamically balance Sen Prop (dynamic balance with the Catto prop was not performed due to time constraints).
Taxi:
Taxing was also different, when I applied power, the aircraft responded quicker to the throttle input. I could tell that the prop was lighter immediately because tailwheel steering felt heavier. I did not see any noticeable RPM difference while performing Mag drop test. Static max RPM was 2,040 on the Catto vice approx 2,200 (have to look at log book for exact #s) on the Sen Prop.
Takeoff:
Huge difference in this area. As soon as I put the throttle in, I can feel the prop grab and me getting pushed into the seat. The aircraft felt like it had more power and it wanted to fly. The RPM built up quicklyand I was flying a little earlier than usual on every takeoff.
Level flight:
Getting rid of the 2600 RPM limit imposed by the engine/Sen Prop combo was nice. At 3,000 ft MSL and 2650 RPM the aircraft felt very smooth. The aircraft was faster and the fuel flow was higher but I can’t quantify how much of that performance gain was due to a difference of an additional 100 RPM. I can say that the aircraft was approx 6 kts faster during those conditions.
Landing:
Landing was comparable between both props. I did notice that due to change of CG I needed more nose-down trim than usual. Also, I needed to fly a few knots faster in order to maintain the same outside picture during landing. With 160 lbs of ballast on the back seat and 20 lbs ballast in the cargo area, I was using 80 kts on final to do wheel landings vice 75 kts. However, this is not due to prop performance. This is due to a change in aircraft CG configuration (more aft).
Formation flying:
The Catto prop shined during this phase. Position adjustments based on power inputs only were much quicker and crisper than the Sen prop. Aircraft reaction to my throttle inputs were almost instant. I could feel surges forward/aft, getting pushed into the seat with power increases and hanging on the straps when pulling power back (similar to constant speed ops but on a lesser scale). I did not expect that type of performance. I felt like I was cheating while station keeping. I purposely went sucked or acute in order to fix the problems and never had an issue, quickly being able to get into position. I joined as #4 with excessive smash and stuck it into position by mostly power changes. Based on experience, that profile would have been difficult to recover without multiple other fixes (cross control, extend outside circle, additional Gs) with the Sen prop. For the most part, throttle movements were smaller than usual due to not needing to overcompensate to then remove what input was previously executed.
Other notes:
¬ The new Catto prop is extremely light when compared to the Sen prop. I would definitely need a heavier crush plate if I made the change to this prop.
- The vibration and noise levels in the cockpit felt calmer than the Sen prop even without the dynamic balancing.
- I texted a picture to my wife and told her to check out the new prop on her plane. She texted me back and said she love it. When I got home she asked me why we still had the old gray prop. I told her she needed to buy it, not my plane.
Hope that info was helpful to you.
Just as a side note, we called Craig at almost 10 PM and told him the prop extension that I had would not work after I had taken my aircraft apart. He told my buddy to fly to his hangar and take whatever we needed off his plane. We took off the cowling and his prop extension therefore grounding his own personal aircraft for a number of days. Craig did not know me at all. I met him and his wife a few days later for a few minutes.
Pics of the next prop under development Shown below.
Overall impression:
Large leap in performance improvement over the Sensenich fixed pitched metal prop during formation flight.
Current aircraft configuration:
-RV-4
-Lyc O-320-E2D
-160 HP/ 8.5:1 pistons / Slick mags
-Sensenish 2 bladed, Model 70CM, 70’ diameter, 78” pitch.
-Configuration for most test flights is 32 gal fuel, me (170 lbs) and 15 lbs of baggage. Total aircraft weight approx 1420. CG 71.6 inch.
-Short gear and old style wheel pants.
New prop:
-Catto prop: Next Generation. Length 70 in/Pitch 73
Pilot:
-approx 450 hrs on this particular RV-4
-FFI carded
A few days ago, I performed limited flight testing (7 hrs) for Mr. Catto. I qualitatively evaluated the performance of his prop on my aircraft as compared to the current aircraft configuration. This was not an engineering test as I did not have time to compare aircraft (weight, CG, etc.) and environmental (temp, DA, Alt, etc.) conditions. So you won’t see many performance numbers. This evaluation was an overall eval (pilot impression) at different uncontrolled operating and atmospheric conditions. The mission task I chose for the eval was formation flying as it would provide almost instant feedback when compared to a “stationary” flying aircraft. OATs varied from 95 to 112 deg F, altitude varied from sea level to 3,000 ft MSL, aircraft weight varied from 1100 lbs to max gross.
Engine starts:
The first engine start was eye opening because I did not expect to experience performance differences that early into it. As the first blade turned I could tell the prop had very low inertia. Once the engine started the aircraft launched forward and then rebounded back (a few times). The plane wanted to go flying already. I have not experienced that before with the Sen prop. And yes it was at approx the same RPM as I use normally. Every other start was like that even at idle power. Once I removed the Catto prop and reinstalled my Sen prop that did not happen again. Both props idled at the same rpm however I had to bump up my RPM to approx 900 on the Catto (vice 800 on Sen Prop) for lower engine vibration. I suspect this is due to the low turning inertia generated by the Catto prop. Once at that RPM the prop felt as smooth as my dynamically balance Sen Prop (dynamic balance with the Catto prop was not performed due to time constraints).
Taxi:
Taxing was also different, when I applied power, the aircraft responded quicker to the throttle input. I could tell that the prop was lighter immediately because tailwheel steering felt heavier. I did not see any noticeable RPM difference while performing Mag drop test. Static max RPM was 2,040 on the Catto vice approx 2,200 (have to look at log book for exact #s) on the Sen Prop.
Takeoff:
Huge difference in this area. As soon as I put the throttle in, I can feel the prop grab and me getting pushed into the seat. The aircraft felt like it had more power and it wanted to fly. The RPM built up quicklyand I was flying a little earlier than usual on every takeoff.
Level flight:
Getting rid of the 2600 RPM limit imposed by the engine/Sen Prop combo was nice. At 3,000 ft MSL and 2650 RPM the aircraft felt very smooth. The aircraft was faster and the fuel flow was higher but I can’t quantify how much of that performance gain was due to a difference of an additional 100 RPM. I can say that the aircraft was approx 6 kts faster during those conditions.
Landing:
Landing was comparable between both props. I did notice that due to change of CG I needed more nose-down trim than usual. Also, I needed to fly a few knots faster in order to maintain the same outside picture during landing. With 160 lbs of ballast on the back seat and 20 lbs ballast in the cargo area, I was using 80 kts on final to do wheel landings vice 75 kts. However, this is not due to prop performance. This is due to a change in aircraft CG configuration (more aft).
Formation flying:
The Catto prop shined during this phase. Position adjustments based on power inputs only were much quicker and crisper than the Sen prop. Aircraft reaction to my throttle inputs were almost instant. I could feel surges forward/aft, getting pushed into the seat with power increases and hanging on the straps when pulling power back (similar to constant speed ops but on a lesser scale). I did not expect that type of performance. I felt like I was cheating while station keeping. I purposely went sucked or acute in order to fix the problems and never had an issue, quickly being able to get into position. I joined as #4 with excessive smash and stuck it into position by mostly power changes. Based on experience, that profile would have been difficult to recover without multiple other fixes (cross control, extend outside circle, additional Gs) with the Sen prop. For the most part, throttle movements were smaller than usual due to not needing to overcompensate to then remove what input was previously executed.
Other notes:
¬ The new Catto prop is extremely light when compared to the Sen prop. I would definitely need a heavier crush plate if I made the change to this prop.
- The vibration and noise levels in the cockpit felt calmer than the Sen prop even without the dynamic balancing.
- I texted a picture to my wife and told her to check out the new prop on her plane. She texted me back and said she love it. When I got home she asked me why we still had the old gray prop. I told her she needed to buy it, not my plane.
Hope that info was helpful to you.
Just as a side note, we called Craig at almost 10 PM and told him the prop extension that I had would not work after I had taken my aircraft apart. He told my buddy to fly to his hangar and take whatever we needed off his plane. We took off the cowling and his prop extension therefore grounding his own personal aircraft for a number of days. Craig did not know me at all. I met him and his wife a few days later for a few minutes.
Pics of the next prop under development Shown below.
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