We'll flesh this out more later.
It seems like everybody is always asking about prop performance, so I'm trying to capture propeller data (diameter and pitch) along with the horsepower that Velocity fliers believe their engine is capable of generating in an attempt to help future prop buyers.
|Scott Derrick indicated that Catto was targeting static of 2250 RPM|
|Brett Ferrell has a 3 bladed Catto rated for 320 HP 68"d x 82" pitch that he has trouble spinning with a engine that dyno tested at 316HP @ 2758 RPM. The highest in flight RPM we've seen is about 2500 and 160 kts. Our highest static RPM to date has been 2150.|
|Andy Millin mentioned that Lonnie Price had a 2 blade was rated for 260 HP with 72"d x 83" pitch|
| Al Gietzen - With my Catto 66 x 80 prop on similarly powered engine (rated 265 @ 2900 RPM prop equivalent); I get about 2500 static at the field elevation of 1400' on 65-70F day. That gets me to about 2950 prop rpm at WOT level cruise; which is about where you want to be with a Catto prop. |
My first prop from Catto was 66 x 85, and static RPM was about 150 lower.
| Barry Gibbons is looking for better cruise speed on his IO-540 300 HP - I have a Catto 3 blade 68 Dia. And 80 pitch, looking for better cruise speed. My static is 2280 and full throttle @ 8000 2640 Ind.153k
I have 68" Dia, 80" pitch with 300 HP Static 2300 @ 2420 elevation and 78 degrees and full throttle of 2640 @6000
| Lou Stedman has a Catto 3 blade - 64 x 72. With my IO-360 the best I could get was 2150 static. He
says that he can pick me up about 150 RPM if I ever see it.
| I've got the same setup IO360 with 10 to 1s on a FG. Craig Catto recommends 66 X 72. If you area a flatlander and only operate at fairly long paved strips, you can use a 66 X 74. With the 72, I'm going to
assume some high RPMs when flat out, straight and level.
| Scott Derrick - I had a Catto 3 blade 64x74 on my Standard RG with a 200+ HP IO360. Below 3000 ft it was fantastic, good take off performance and excellent cruise RPMs below 18,000. As your field elevation got more and more higher, like 6500 ft, the takeoff performance could be described as anemic.
Diameter is now 66. Was 68.
The pitch is still 88, but Craig added filler to the back side which defeats or un pitches the prop aerodynamically. I'm paraphrasing.
|Gordon Putney - I have a 66" X 82" Catto three blade on a 260HP IO540. @ 900 msl std day, get 2340 static, rising to 2450 ato.|
|Dave Dent - Mine was a 67X78. It should have been 67X80. I'm sure it would have done better. Paul Calhoun had the 67X80 and it did better. Catto told me later that mine did need the 80. Paul's did something like 2300 static but on take off it didn't do as well as mine. I got a good 1000 plus but on the upper end mine didn't do as well. Paul's was seeing a good 190kts. Mine only saw a little over 180kts. Some where I have this all written down. But by memory this is all that comes up. I'm back to the MT right now and I was suppose to have gotten my new Vesta blades this week but it didn't happen.|
| Ron Brown - I started off with a 66" x 72" Catto on my 173 Elite RG with Lycoming IO 360, 200 HP. It was a bit too long legged, static RPM was less than 2200 rpm and maximum with wide open throttle was 2550. Take off and climb were anemic. I sent the prop back to Craig and he repitched it to 66"x70" and it felt like I was starting off in "2nd" gear versus "high" gear. (With an M/T, you can start off in "1st" gear).
My static RPM is now 2400 rpm and WOT is something over 2700 rpm. The interesting part is that the top speed is pretty much the same at 168 knots vs. 165 knots - just more rpms and HP.
Here is a quick way to estimate horsepower.
You said std. day, 2450 rpm's and 900 msl... 260 hp IO-540...
Torque = MP
2450 rpm's is .907 % of max rpm's
900 msl is about 29" of MP= .969 % of max MP(rule of thumb torque)
.907*.935=.848 % of total HP
That's about 230HP give or take... At take off, Wide open throttle...
MT is the "standard" for the Velocity, at least for constant-velocity propellers. MT probably has 60% of the flying fleet, with most of the rest using fixed-pitch props of one sort or another. The MT is typically installed as a three-blade unit, though there are a couple of folks using 4 blades. You can also purchase hydraulic or electric actuation. The MT prop provides solid performance, but some have questioned it's durability.
Aero Composites is the new kid on the block, and although they run a little more expensive than the MT, are purported to have much better durability, and perhaps somewhat improved performance. There are only a couple of flying examples on Velocitys, so hard comparisons are hard to make right now, but the folks who have them report being happy with the purchase.
Here are a set of pictures from Rene Dugas who has converted his pretty retract from an MT to an AeroComposites and reports good results. He had a custom paint scheme added to his prop to match his airplane, and provides some nice cross-sections of the prop construction as well.
CattoCatto's propellers are the current leader in sales for the high-power fixed-pitched crowd (mostly XLs), and are all custom-made for the target aircraft. Catto is so popular that lead times can be a problem, but the quality is excellent, as is service after the sale.
I don't have much information on the IVO props other than they are not recommended for many (all?) of the 4 cylinder aircraft engines, but are fine for the rotary and maybe all of the automotive engines. I believe the blades have a fair amount of flex, and some of the hubs are in-flight adjustable, others are ground adjustable. The IVO might also be suitable for the Franklin.
I have a Franklin Ivo combo and can report the following. I have good RPM and acceleration at my high altitude (8300) airport but I have to toggle toward cruise toward the end of takeoff to prevent RPMs from going too high. I am disappointed in my high end speed. At 10,000 ft and 2300 rpm full throttle, I show about 135 - 140K indicated.
I don't really know anything about Prince, so someone else will need to fill this in. I do know that Doug Holub ordered a 2-blade 68/78 Prince propeller. There was a 12 week backlog at the time. It's going to be mated to a 190 hp engine and a FG Velocity.
I don't really know anything about Performance, so someone else will need to fill this in.
I don't really know anything about Vesta, so someone else (Bob Buls?) will need to fill this in.
I don't know much about Vari either, other than Milt Mersky (a Velocity builder) is a dealer. I'm not aware of any flying on Velocity aircraft yet.
Hartzell tested a propeller with the factory in 2005, making a two and three bladed propeller with the semi-scimitar blade design just like that used on the Cirrus aircraft. It was considered nonviable due to the vibrations that the pusher installation was placing on the metal prop.
I have spoken with Hartzell about the Velocity program and the propeller. Albert Khasky also spoke with the gentleman at Hartzell that was responsible for the test. The report from Hartzell was the vibration was not attributed to the pusher configuration. It was not related to the prop in the shadow of the wing. They believe it was the specific mating of the prop to the 300 HP Lycoming engine. They did not rule out other engine combinations. They belived there was a good chance the prop would have been successful behind a 260HP Lycoming. (Andy Millin)