Need Advice

Now that I have my engine I'm thinking about fixed pitch propellers. My plan was to go with the extended Sam James cowl on my 9A. Knowing that the 9A is a bit tail heavy, what are your recommendations for propeller?

My initial thinking was a 3 blade Catto cruise prop with nickel leading edges, but I'm wondering if the weight of a standard aluminum Sensenich prop might be welcomed.

Thanks again everyone.

T.

I recommend a constant speed prop on the RV-9A. It will help with center of gravity and will also make for much better performance and cruising! I have one on my 9A and would never go to a fixed pitch on a cruising airplane. IMHO

Second on the constant speed prop - I'll never go back.

With an IO360 and constant speed up front I was fighting a NOSE heavy tendency, and ended up moving several remote-mounted avionics and the battery aft of the baggage compartment to compensate. I also have extended range fuel tanks though, which required a bit more aft empty-CG so I would still be in limits with 67 gallons in the wing leading edge.

Thanks guys

Constant speed prop is not an option at this point (maybe in the future).
So given that fact, any advice for a fixed pitch prop? Catto? Sensenich? Composite? Metal? Ground adjustable? Weight? Extensions?

Av8torTom said:

Constant speed prop is not an option at this point (maybe in the future).
So given that fact, any advice for a fixed pitch prop? Catto? Sensenich? Composite? Metal? Ground adjustable? Weight? Extensions?

Click to expand...

There's plenty of data in the archives about the relative CG's of airplanes with metal and wood props. I have a composite/wood prop and a 10 pound prop spacer to get the CG on the -6 to what I consider a good compromise.

Personally, with a -9 (i.e. a non-acro aircraft), I'd go with the metal prop. They are efficient, don't suffer in the rain, and will help your CG. No, you won't be able to spin the engine all the way up to 2700 RPM, but I'm not sure that's as important in the RV-9 "mission".

Love the Catto on my -9A. I've got the two-blade 70x70 with nickel leading edges. Super smooth operation, and hits the Van's speed numbers nicely.

Minimal issues with W&B on my plane, even with a lightweight SkyTec starter. If I get down to 5 gallons of fuel in worst-case W&B scenario, I'd have to reduce baggage from 100 lb to 90 lb to stay within range, so no big deal....I've never landed with less than an hour's reserve. Went to Oshkosh with the cg pretty far aft (195 lb pilot, 250 lb copilot and approx. 90 lb baggage) and the the aircraft handled beautifully. You could always fit a boat-anchor standard starter up front, or weighted crush ring.

I'm a big proponent of FP props....less complexity, workload, cost and maintenance. I might consider a CS if I were based at a high altitude airport, but I'm very pleased with a solo-weight climb rate of 1300-1400 fpm.

And the less weight you put on that nose gear, the better (while staying within cg range, of course).

Cargo 3 Blade

I have a Catto 3 Blade on my 9A and I have no issues with W&B. I?d have to have two +200 lbs. people and near empty tanks to be too far aft.

I was worried about it before I finished. But it has not been an issue.

Michael

Wood prop

I really like my Sterba cruise prop. Light, runs smooth and inexpensive. No issues
with the CG. I can send you my W&B spreadsheet.

I've got a 9A with an IO-360 so my numbers will be slightly different than yours but...

I started with a 3 bladed Catto prop just as you described. I loved that prop and it performed better than any certified airplane I ever flew (granted thats not a long list). However last year I got the bug to go constant speed so I installed a Whirlwind 200RV prop. You can read all about my thoughts on the process on my blog.

Here are the high points.

1. Cruise is no better with the constant speed..in fact its slower but only by a knot or two. To be fair to the Whirlwind, it is limited to 2700 rpm so I have my governor set so that I can't get above 2650 in cruise. The Catto would turn at 2750 which means I was getting more HP out of the engine.

2. Climb...holy **** the climb! The constant speed out-climbs the fixed pitch by a large margin...and thats saying something because the Catto would climb at 1500+ fpm.

3. The constant speed prop is quieter in cruise because I can pull the engine rpm back.

4. The ability to slow down with the constant speed prop is great but the con to that is my glide ratio really sucks now. In my informal testing I could glide at >10/1 with the Catto at idle but with the constant speed at idle that number drops to about 8/1.

5. The constant speed prop is has much more vibration than the 3 blade Catto. I even dynamically balanced my prop to 0.0 IPS and still have much more vibration. I've gotten used to it but that took a bit of time.

Was the conversion worth the money I paid? In my opinion the answer is no. The Catto is that good.

Not that it matters as you're already committed to a fixed pitch prop, but another advantage of the constant speed prop is drag on approach and rollout. And if you're in frisky up and downdrafts, like west Texas in the summer, you won't be constantly adjusting your power to keep the RPMs under control when the autopilot is holding altitude.

I've got a Sensenich fixed pitch on my -9A, but I'd much rather have a constant speed.

Along those lines, any thoughts on three blade vs two blade props in terms of getting the cowling on and off? The cowling on my -9A is moderately uncooperative, and that's with a two blade prop...

If you're stuck on a FP prop, Craig Catto makes an excellent prop for the purpose.

A constant speed will give you the best climb, top end, and cruise - but the Catto can come very close in some areas and slightly exceed in others, at a little less weight and significantly less cost.

But I still love my WWRV200 and won't trade for it. I absolutely love holding 2000 fpm on initial climb and having airspeed to spare.

Thanks!

Some great information for me to consider here.

Thanks everyone