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Constant Speed Prop PA 18 Experimental with Titan 180 hp

Hi Guys and Gals,
Does any one have info or suggestions on performance and details. Which constant speed prop do you recommend for Super Cub with 180 hp Titan Engine fitted. 31 inch bush wheels cruise and performance .
 
Yep I have that on my list expensive . Do you know of any alloy props to suit
Since you have 180 hp you should seriously consider a carbon fiber blade prop for center of gravity purposes. Don't even think about the aluminum alloy blade due to the added weight where you do not want it unless you are willing to add ballast to the tail. Also some of the aluminum blade props have harmonic issues which restricts use in certain rpm ranges. There are dynamic balance weights which help with this issue.

Where does the governor mount on your engine??? If it goes on the accessory case you will need to cut a hole in the firewall for it to fit. First make sure that there is no interference BEHIND the firewall. If the governor mounts on the forward crankcase you're home free.

The Whirlwind is a good performer for less $$$ than the Hartzell. http://www.whirlwindaviation.com/props/STOLGCSseries.asp I have the ground adjustable version and it is a great prop. It's too bad that I have governor interference issues. The cruise performance varies between 100 & 120 mph depending on blade pitch, climb between 1000 & 1400 fpm. This on floats not wheels.
 
The Carbon Cub FX3 uses the Trailblazer and it performs quite well, rips off the ground and will cruise 135 plus with the injected 360 engine. Several folks here running the MT constant speed prop on certified 180 hp Super Cubs. Randy Goza raves about the Whirlwind constant speed on his SQ2.
 
The Whirlwind constant speed model that most Cub guys use for <200hp is the 200G-CS. Look at their website and you'll see a couple of SQs. You'll also see the 200A prop but it requires more power. They're easy to distinguish. Call Whirlwind (Ohio) and ask them about their props and governors. Very educational.
 
I would be more worried about rock damage on aluminum blades since a ding in aluminum creates a stress riser location. This stress riser could (not always) create a catastrophic blade failure when you least want it. A ding in composite is usually just a ding. Composite props have special leading edge protection for this situation.
 
Lots and lots of folks are running a Catto composite prop and I have not heard of anyone complaining of rock damage.

Bill
 
If you operate on gravel rocks will get tossed over the top and forward from tires. Most composite props use nickel leading edges. Very, very durable. Not a problem there. Where composite props are vulnerable is on the back side of the blades. They definitely get dinged easier than aluminum. The good news is with some JB weld or other quick set epoxy the dings are easy to repair. Whirl Wind recommends filling dings with gelled Super Glue. You need to build in layers. Too deep a fill and it doesn’t cure in the middle. I found JB Weld much easier to use. If it sags a piece of Scotch Tape makes a good peel ply to hold the epoxy while it sets. Simple tools, simple repairs.
 
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Most composite props have either nickel or stainless steel leading edges. They are much harder than aluminum. Rockwell hardness of an aluminum prop is 7-8 and the nickel leading edge on a cado is like 80. Flying the same missions with my Borer as someone with a Ctto his prop still looked new and mine looks terrible.
 
I am running a 80" Hartzell constant speed propeller on Bushwacker 2.0, I have wanted to try a composite propeller. I decided to try an MT 80" Ultra because that is what I was steered towards by Flight Resources with the guarantee it would out perform the Hartzell I was currently running. I am not going to just lay down $13,000 and assume it outperforms so we did a series of test one morning to determine if it really did.

Here are the results:
Today was test day for the MT propeller. I ran tests for the propeller I currently use versus the new MT propeller, both propellers are 80" long. I had two friends help, one is a mechanical engineer and has done a lot of testing for various aircraft projects. His name is Doug Keller and is fairly well known in the Super Cub world. We did all the tests on the Hartzell first. We started at 8:30 am and finished up testing with the MT by 10:45 am. We did not add any fuel so the MT would see the aircraft with the lightest load (not taking into account that the propeller is also 25 pounds lighter). These are obviously not scientific tests but were intended to see if there was a big difference between the two propellers. As you will see below the numbers do not support that the MT propeller will outperform my current Hartzell by any margin.


Pull test with load cell.
Hartzell pulled 785 pounds 2650 static using a True Tac
MT pulled 775 pounds 2680 static using a True Tac


We did a 150 foot take off run. Pull up to a line, go to full power, release brakes and make the 150 foot run at full power no flaps stick neutral. See results below:


Hartzell
5.50 seconds
5.32
5.23
5.08
Average= 5.28


MT
5.25 seconds
5.59
5.12
5.33
Average=5.32


I did a climb from a dead stop at sea level to 4000 msl climbing at 80 mph at 2600 rpm


Hartzell
3.14 Minutes


MT
3.16 Minutes


I put the airplane in a climb at 2000 msl and climbed to 3000 at 75 mph and saw a sustained climb of approximately:


Hartzell
1500 fpm (I used my Garmin G5 so hard to get very accurate reading with it)


MT
1500 fpm

In the end I decided that it was not worth the $13,000 to me. It was smoother, it had better braking action when I pulled the power and the weight off the nose did feel better when light. The problem with my airplane is I built it with the weight of engine and propeller in mind so taking weight off the nose when loading the airplane up is a negative. I run out of aft CG before I run out of room. If I had a Super Cub and wanted to run a constant speed propeller this would be one propeller to look at. The guys at Flight Resources were top notch with regards to customer service.


 
I would if it was free but it is not cheap to ship propellers, that little test cost me 660.00. I not sure I could get the same guarantee on the Trailblazer.
 
It'd be interesting to see how a Whirl Wind compares. You can try my 200A while it's off. Maybe not the best match for a 360, though.
 
There is a brand new Hartzell Trailblazer just a few miles from me but I could not get the guy to let me try it:cry:
 
I would be more worried about rock damage on aluminum blades since a ding in aluminum creates a stress riser location. This stress riser could (not always) create a catastrophic blade failure when you least want it. A ding in composite is usually just a ding. Composite props have special leading edge protection for this situation.

^^^^^^ This ^^^^^^

MT prop with the nickel leading edges hold up much better in my opinion. I have NO erosion on my MT Ultra with the nickel leading edges.

I would recommend the MT Ultra based on my experience with a 3 of the MT props and the Hartzell Trailblazer.

Kurt
 
Here’s a Mike Patey video of repairing a Catto. Google search “repair a carbon propellor” and you’ll get several videos, mostly from Hartzell. Repairing dings is a nuisance or a pastime depending on your mood, but composite props are the real deal.

https://binged.it/2MNyunV
 
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