Prop Options O-320 160HP

[kevinbarton1]

I am ready to purchase my prop for my rebuilt PA-18 and wanted to get some knowledgeable advice from some real supercub guys on the type of prop I should consider. I have a O-320 160HP with 3" extended gear and 31 inch tires. I do not do any serious bush flying mainly because I live in TX and do not need to, but would like to get into some of the more challenging flying now that my plane is more capable. Previously had a O-235 so there just was not enough power to do much off airport landing for me to feel safe/comfortable. I know the Sensenich is an option, but aesthetically I do not like the look without the spinner. Is there another option other than the Borer? I only ask because I know it is heavy. Has anyone flown with the constant speed MT prop? My panel has been cut already and I was not planning to install a constant speed prop at this point, but I did not know it was an option until I started reading the forums earlier. Does anyone have any experience with the CS MT prop? Just trying to find the best option. I wish the Catto was STC approved. I have heard lots of great feedback about that one.

 

[PerryB]

The Mac 82-42 or 82-43 is a good choice for a fixed pitch, high performance (STOL performance that is) prop. I don't know what's happening with the Catto props. I'd swear I heard last spring it was a done deal, but I guess not.

 

[kevinbarton1]

ok, seems like pretty much everyone runs the borer prop. The -42 is more for climb and the -43 more for cruise? Seems like some say the difference in runway performance is minimal, but you get a little more speed out of the -43 in cruise? Also I thought the Borer prop was 84 inches?

 

[nanook]

On the 160hp, I run the Borer in 41, it is an 82” prop. If your crank is still hollow, you could run a constant speed.

 

[PerryB]

The difference between the two is not great but yes, the lesser pitch favors T/O & climb to a small degree. Typically 1 inch of pitch will produce a change of about 75 RPM. In terms of speed, adding an inch will probably result in a cruise increase of about 3 MPH for a given RPM. I've read a couple posts over the years claiming a 43 or 44 pitch will reap the speed benefit with no measurable loss in T/O performance, but thats just not possible.
As to the 80" Sensenich, I have one and am not very impressed. It's not very efficient due to it's thick airfoil. Mine is an 80-40. Going to an 82-41 Borer improved both takeoff and cruise. I've since done a couple minor power mods (oficially a 320/150) and had the prop bumped up to 42 pitch.

 

[kevinbarton1]

I knew there was something else in the engine that would need to be changed to accommodate the CS prop. The crank! Thanks for that post!!!

 

[kevinbarton1]

What do you think the sweet spot is regarding take/off and cruise? Would you get a -41 or -42??

 

[Gordon Misch]

I have the 82-42 on my PA-12 with 160 HP engine. I get about 2580 RPM climbing out at 70 mph, sometimes 2600 depending on the air.

I get upper 90's TAS (statute miles) in cruise at 2500 RPM. I can easily overspeed the engine in level flight, so have not tested for max RPM in level flight.

I have Sutton exhaust, and my understanding is that Atlee's hotrod muffler increases power some.

I have the square style airbox with Donaldson air filter, and Charly Center told me I could realize a few more RPM (he said close to 50, but I don't know what flight regime he was referring to) with the Supercub style round filter.

In short, my experience is very similar to Perry's with his PA-12.

 

[PerryB]

42 gets my vote.

 

[supercrow]

I have been running an 8243 on my warmed over 160 for years, and I like it, but am going to try something lighter. I bought a ground adjustable 80" Whirlwind, but won't be getting it on until spring as I am doing some fuselage mods this winter. Will give a pirep in the spring.

 

[Steve Pierce]

You can run the same spinner on the Sensenich as the Borer. Plenty of good gravel bars in my part of Texas for off airport ops. Like my 41" Borer to get out quick. It is a Super Cub, they are slow. You need a hollow crank O-320 which most are for the MT and a pad for the governor along with a Sutton exhaust. The MT spins up to 2700 rpm immediately and slows down fast acting like a speed brake. All depends on the mission of your airplane. Sensenich should have their bonded stainless leading edge prop approved shortly. They are sending me a few to test. I have a feeling they are going to perform between the Borer and the metal Sensenich with less weight.
Some threads on the MT.

http://www.supercub.org/forum/showthread.php?24529-MT-Propeller-STC-now-available

http://www.supercub.org/forum/showthread.php?33775-MT-Propeller

http://www.supercub.org/forum/showthread.php?36049-MT-Props

The Brazos River west of Graham, Texas this past Saturday.

 

[PerryB]

Steve, I think he's talking about the 80" woody which is thicker and puts the front bulkhead too far forward, at least mine is. Are the new ones thinner?

 

[Steve Pierce]

Steve, I think he's talking about the 80" woody which is thicker and puts the front bulkhead too far forward, at least mine is. Are the new ones thinner?

Ah, that makes sense. No, same prop just bonded leaded edge vs the riveted. Can be replaced an unlimited amount of times where the riveted is only replaceable a couple of times.

 

[GeeBee]

If you are starting from scratch, and you are willing to spend the bucks I would seriously consider that MT electric constant speed. I've have been eyeing it myself.

 

[kevinbarton1]

Steve,

I am almost certain I have a hollow crank. Engine originally came off a twin comanche which would have had CS prop. It seems attractive to have the ability to cruise faster and still get the high RPM for take off. From the posts I have read, it seems like it is rather light for a CS prop. Is the only disadvantage the cost?

I def want to come up to Graham soon and do some flying this spring. Should have the plane put together by then. I am just north of San Antonio.
Kevin

 

[john schwamm]

I have a Borer on my cub with Lycon hot rodded 0320, Altee exhaust, repitched to about 42.5, closer to 43.
I have 35" tires, running 2450 it gets about 90-95mph. Like the added speed and do not feel I lose much on the low end performance.
Real slow with a 41, maybe 85 mph range. In Texas you sure would like to have the added speed I would think.
John

 

[DENNY]

On a 82 inch Borer you should see aroun 25-35 static RPM change with every inch change. Speed change from 40 - 43 is 7 mph at 2400 RPM. Every engine/plane will be a bit different but that is a good ballpark figure. I run a 82/43 for every day flying and I’m very happy with takeoff performance and speed.
DENNYi

 

[kevinbarton1]

Yep. I think that has been the consensus regarding the pitch. Steve got one ordered for me. Do you like the Atlee exhaust?? What other options are there? Not sure if it matters, but I'm planning to put it on amphibious floats part of the year. Seems like I've read something about needing a special exhaust?

 

[kevinbarton1]

Awesome, thanks Denny for the reply. I'm looking forward to getting it.

 

[john schwamm]

Atlee exhaust is good, gives more power and great sound, less restrictive and eliminates some inspections.
Believe Sutton and other exhausts are out there, but no experience there.
I think the mid range pitch on Borer for some added speed is best unless one is really working the short stuff all the time, but getting to and from faster is a good compromise to me.
John

 

[RaisedByWolves]

Sutton is a great exhaust, gets rid of the AD and moved the muffler away from the firewall, you won’t get as warm in the hot summers.


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[DENNY]

I like the Attlee Hot Rod exhaust but it is loud!! It gets rid of the AD and helped with CHT's on climb out.
DENNY

 

[Steve Pierce]

Ditto what Tom and Denny posted. Atlee gets you a bit more rpm but is heavier, louder and puts that heat against the firewall. I really like my Sutton exhaust.

 

[RaisedByWolves]

Ditto what Tom and Denny posted. Atlee gets you a bit more rpm but is heavier, louder and puts that heat against the firewall. I really like my Sutton exhaust.

Louder. A lot louder. I didn’t notice until I changed to the Sutton. I could hear my self think.


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[kevinbarton1]

Sounds like the Sutton is the way to go!!! Thanks guys for your reply!

 

[peterdillon]

We have run an MT with reverse for the last 10 years or so. Wouldn't dream of of putting a borer back on. Better in every way except price.

 

[kevinbarton1]

We have run an MT with reverse for the last 10 years or so. Wouldn't dream of of putting a borer back on. Better in every way except price.

I can only imagine it is probably a dream. I would love to put one on now, but the cost of the rebuild is getting more costly by the week. I will definitely consider at some point in the future. I just want to get the wings back on and flying for now. I looked at the cost and figured I just could not justify it right now.

Thanks for letting me know how much you like it though. It may be more practical when I get my amphibs!!!

Kevin