What performance with Catto 3-blade + O-320 (160HP)?

I am curious as to the performance people are seeing with their Catto 3-blade props.


If you have any info on the following configuration, please share.

O-320, 160 HP, RV6/RV6A or RV7/RV7A

If you have it, please share Prop diameter+pitch,RPM, MP, Density Altitude, IAS, TAS.


I plan to do some testing on with a 66x72 and would like to know what to expect as compared to what people are seeing.

I have been to Craig's site and have talked with Craig but wanted to get some data from actual configurations so I could see what "variability" to expect.

Thanks!!

p.s. It seems that it would really be nice if a database of performance could be developed for a few of the popular RV configs (engine/prop combinations).

Data for 160 HP but IO-360

My prop is 3 blades, 66" and it was a 74" pitch, but got repitched to take a bigger bite. The effective pitch is now 80.3" but I don't know the nominal pitch. I've asked Craig, but haven't heard yet what the new nominal pitch is.

My performance at 2/3 power according to my GRT is:
Weight = 1600 approx. (Van's solo wt is 1400)
DAlt = 6300
Alt = 7500 close to PAlt
Temp around -9 C, maybe a little warmer
TAS 160 kts, but 156 if running LOP at 7.2 ~ 7.5 gph. (=184 mph)
21.8~21.9 MAP X 2340 RPM.
Van's says it should be 190 at 8000 for the 160 hp engine. He used a CS prop.

Since 2/3 * 180 is 120 and 120 is 3/4 of 160, this would be close to 75% for a "320".

I would guess you could do a little better if WOT and/or higher.

My speed, reported in my thread, at 75% is 175 kts, or slightly better than Van's numbers, so this is a reasonable benchmark for you to use. pitch.

Just checking again ...

Anyone else with any data in this area?

ANY data at all for an O320? There *must* be something out there as there seems to be a lot of these props that are flying and that have obviously gone through flight testing.

Please share.

Thanks,

It seems to me that this combination is most common on the 9A, and since you asked, here goes.

Our 9A has a 160 hp O-320, EMAG/Slick and Catto three blade. I see 184-186 mph TAS at 8000' DA WOT. Surprisingly, it is somewhat faster on up higher, but I won't quote here as I haven't done a good test to determine just how much, or where optimum altitude really is. This speed increase may be due to the longer 9 wing--don't know. Light, I have seen as high as 2600 fpm in cold air. Fully loaded 1400-1500 in normal conditions below 3000' at around 100 indicated. The prop was built by Craig as a cruise prop for EI. Initial TO rpm is down around 2120-2150, depending on the day. Still gets off the ground quick enough for me, but obviously well longer than a CS would do. FWIW, I expect to see speeds of over 190 at 10,500' when I finally get good testing done at that altitude, or at least that is what first impressions indicate.

Trust Craig. I think he will give you an honest prop that pretty much follows Van's "Total Performance" criteria. There might be props better at this or that, but all around, I think his props are hard to beat. Just my $.02.

Bob Kelly

2 Blade Catto's are faster...

Post 9/11 we had 9 RV4's in my F16 SQ giving us a large database for performance of different engine/prop combos. One of us had a 3 blade Catto 160HP RV4. At the time I owned a 150HP Catto 2 blade 69 X 72 RV4. Suprisingly I could outperform the 3 blade in every category except smoothness. My SL cruise numbers with the 0-320 ND 150HP were: 2400 RPM 150 knots, 2500/157, 2600/164, 2700/171. The 3 blade 160HP was roughly 5 knots slower for equal RPM. The 9A is a very different airframe but the same physics should apply. This was seven years ago, supposedly Craigs new 3 blades are better. BTW, I bought Craigs first 2 blade RV prop in 99' and from start to finish he was a class act.

If you want a fast, well made 2 blade fixed pitch prop you can't beat Craig Catto's product. Gary Hertzler's 2 blade performs very well as does the MT FP and Margie's Claw although she currently isn't making props. Also, the new Sensenich ground adjustable composite works great on Subie RV's and is now approved for the 0-320. Lots of choices...
Three blades? The Ellipse is the way I would go..

Rob Ray
HR2