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0320 vs 0360 on the nose what are the real issues?

DENNY

SPONSOR
Weather still sucks and it will be a while before we get any good ski weather so time to pontificate and get opinions. The questions of 160 vs 180 hp on the nose. I have a 160 hp and it does quite well. I am usually off the ground as fast if not faster than the 180 cubs. But once in the air I have to do pilot stuff for a bit to keep it up, The 180 cubs just pull back and fly!! They also burn less fuel for the same speed/distance. Some say with the added weight on the nose they cannot fly as slow. Is this true has anyone taken a club prop off and stuck on a Cato and saw a slower stall speed (no wind GPS speed only please) I would say hard breaking with a big metal prop could be an issue for sure. For the guys that like to do math how much weight in the tail would you need to offset say 30 lbs on the nose? While you are at it what about moving the engine back 1 inch. Just things to ponder on the cold nights.
DENNY
 
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I have flown both, and far prefer the 160. My Decathlon has the 180, and I kinda wish I could replace it with the 160.

My impression is that the 160 burns 7 1/2 gph; the 180 in the Dec with fuel injection is over 9.

The best Cub I ever flew was an otherwise stock 1950 model with flaps, balanced tail, and 160 Lyc. It is no longer quite as stock, and doesn't fly quite as good, but it is still a delight. Originally 115 mph on 7 1/2. Still does 110.
 
What was interesting last year when a group of us went to Quebec, we had 4 planes in the group a Scout with CS, -18 150, -12 160, my -12 180 with 8242 , I was leading the group with my 180hp, I needed to run about 2200 for 90 MPH or so to set the speed for the -18 unless he wanted to run harder.
When I leaned back watching my EGT and CHT, many times about 7.5-8.0 GPH, it was really amazing that so many times I could look at my fuel flow and call out I have used XX gallons and the rest that had fuel flow would also agree and when we filled all used about the same fuel burned even though we are so different.

SO there is my experience with different engines on similar size planes, how do you manage the fuel flow-mixture, if I didn't lean it out yes it would be about 9GPH. But there again I can go 125 hours with out having fouled or lead build up on the plugs too.
Yes this will start the whole leaning debate, how can you do that!! I just do it, watching EGT and CHT and Fuel flow. Also know when I am building ice as one cylinder EGT drops so pull carb, know it before I feel it while cruising. Happened a number of times on the trip, lots of moisture in the air on that trip.

Issues, biggest I see right off is the engine mount- long or short, Prop-type, Electrical-with-without, SO many other variables.

Doug
 
Take 30# off the nose moves CG back about 1.2”
Add 17# on the tail does the about the same movement.

So taking the big club paddle off the nose and put a Cato on
will make a huge difference in CG and how it flies.

Sort of like a long mount vs short mount 150-160
 
I guess I don't run 180 hp engines at 2200 rpm. Mine is placarded red from 2000-2250. I run it 2400 squared until I hit full throttle. Getting old and tired, but fine wire plugs make it think it is a 22 year old hard body.

You really shouldn't compare a 12 with an 18. Unless the 12 is highly modified, it is an entirely different airplane.

Opinion. Gordon's is the only 12 I ever flew that I liked. They are faster . . .
 
I guess I shouldn’t compare a -12 to a-12 to a-18 or to a Scout all different motors
all burning about the same amount of fuel over the same distance ��
 
Doug, Your example has backed up my theory that there is a "drag" wall which occurs around 110 mph. Below that speed the drag portion of aerodynamics does not have the same effect as it does over 110 mph. It takes about the same amount of BTUs to move all airplanes in the lower speed range over the same distance. When the airplane is pushed past this 110 mph wall, the aerodynamics cleanliness becomes more important unless there is a copious amount of fuel flowing through the lines. Walt Mooney was one of the first to demonstrate this with his 65 hp Mooney Mite.
 
The J3 and Super Cub have similar drag profiles. One year long ago a buddy and I set out for Lock Haven. His was a PA18-150 with VGs and cables; mine was a stock J3 with 85 and wing tank. We flew together, which means he throttled back and I pushed it a bit. At each stop he took on almost twice as much fuel as I did.

Yes I accept that others get different results.

My cars are like that. My ancient Mustang convertibles - 24 mpg for the V8; 14 for the six. Same driver, same route to the airport, no drag racing.

The reason I do not like the 180 HP on the Super Cub is it makes it handle like a piglet. It does go straight up, and that was fun.
 
The J3 and Super Cub have similar drag profiles. One year long ago a buddy and I set out for Lock Haven. His was a PA18-150 with VGs and cables; mine was a stock J3 with 85 and wing tank. We flew together, which means he throttled back and I pushed it a bit. At each stop he took on almost twice as much fuel as I did.

Yes I accept that others get different results.

My cars are like that. My ancient Mustang convertibles - 24 mpg for the V8; 14 for the six. Same driver, same route to the airport, no drag racing.

The reason I do not like the 180 HP on the Super Cub is it makes it handle like a piglet. It does go straight up, and that was fun.


If they fix the CG they will fly really nice and straight up! All about CG!! Unbalanced planes are that unbalanced.
 
With the 180 hp there is a change to the empty weight CG but there are other issues to consider, depending on what conversion you have.

I converted my 18A to a 180 after nearly 1500 hrs with the O-320; of which about 500 were with the thrust line change. I had always heard the discussions about the nose heavy feel and was concerned, but I wanted to clear the trees easier when leaving my cabin.
I chose the Penn Yan conversion kit.

In discussions with Mark Englerth about the thrust Line effect, he said that for what ever reason Penn Yan used about a -6 degree setting for the engine. (could have been from the original Johnson STC that they purchased). Piper used -4 for the O-320.
The TL kit is approved for the 180 so we kept it. That combination brings the engine up to about -2 degrees.

I was surprised as the cub handled nearly the same as it did with the 150. We did lighten it up with the normal alternator, cooler, starter changes but it does have the heavy prop. I think that works out to about a wash in weight changes. There is an amazing rate of climb improvement.

On approach with either engine I apply flaps as I slow down and therefore never touch the trim. With the 180 hp it is exactly the same; no need to adjust trim. It doesn't feel any more nose heavy now then what it did before.

I rarely fly super slow approaches as I am mostly on floats. This thing really performs well and it will definitely get off the ground quicker then I would with the 150 hp. It was a huge improvement on floats.

Mark shared a theory that Penn Yan installations of -6 degrees, pitch the engine down so much that the thrust is actually pulling the nose down at slower speeds giving it that "heavy feel".

He also said that the Charley Center STC uses about a -2 setting, and is thought to be a better performer then a stock Penn Yan. If you have one of these you wouldn't want to use the TL kit.

I have two cubs. A 150 hp 18A with stock wings which is really nice and flies great. The 180 hp has squared wings and long ailerons. If I sell one of them it will be the 150. This 180 18A is "hands down" my preference!

If you have a 180 hp engine that you think is really nose heavy; you may want to check into the trust line change.
 
Following along with Ed’s statements, and giving Mark Englerth and the ThrustlineMod credit:

1. O-360’s usually have a coarser pitch prop than an O-320 prop. Thus, at idle they are pulling harder, and at cruise they are pulling “further”. Thus, O-360’s will get comparable speeds (and fuel burn) at lower power/rpm settings, and will have more thrust at idle.

2. An O-360 thusly pulling harder at idle than an O-320 due to the coarser prop, and with a downthrust mount, will have a nose heavy feel. The need to trim relatively LOTSA noseup and hold the stick back is a down force on the tail that the wing must carry (along with the DRAG of the nose up commands).

This translates to an airplane that doesn’t fly as slow as a sweetheart O-320 Cub. And you can feel it and see it!

The longmount 150/160hp PA-12/-14 is noseheavy when empty.

My latest -14 project will be shortmount and O-360. No question in my mind which airplane I wanna fly.
 
My 2 cents is that a light cub with a160 is the best. It will get off and get in quite a bit shorter, always. When loaded heavy, the 180 can sometimes be better and at high altitude it will have more grunt. But overall, by far, the best all around Cub is a light 160.. That said, not everyone agrees... ha ha.. so there ya go.. It’s an age old debate.. My cub is a hand propper, with no excess weight at all.. But she’s a humdinger.... I wouldn’t trade it for anything.. and I’ve owned 2 180hp cubs.
 
Just to stir the pot, I've flown several J-5s with 0-235s, they were decent but just so so. Then once I was asked to ferry a no interior 85 hp J-5. That airplane was amazing, very short take off and landing distances without effort. Similar to a J-3. That airplane sat around never flying again. The owner took the wings off and took it home. Later he went west and I've heard nothing about the plane since.
 
With the 180 hp there is a change to the empty weight CG but there are other issues to consider, depending on what conversion you have.

I converted my 18A to a 180 after nearly 1500 hrs with the O-320; of which about 500 were with the thrust line change. I had always heard the discussions about the nose heavy feel and was concerned, but I wanted to clear the trees easier when leaving my cabin.
I chose the Penn Yan conversion kit.

In discussions with Mark Englerth about the thrust Line effect, he said that for what ever reason Penn Yan used about a -6 degree setting for the engine. (could have been from the original Johnson STC that they purchased). Piper used -4 for the O-320.
The TL kit is approved for the 180 so we kept it. That combination brings the engine up to about -2 degrees.

I was surprised as the cub handled nearly the same as it did with the 150. We did lighten it up with the normal alternator, cooler, starter changes but it does have the heavy prop. I think that works out to about a wash in weight changes. There is an amazing rate of climb improvement.

On approach with either engine I apply flaps as I slow down and therefore never touch the trim. With the 180 hp it is exactly the same; no need to adjust trim. It doesn't feel any more nose heavy now then what it did before.

I rarely fly super slow approaches as I am mostly on floats. This thing really performs well and it will definitely get off the ground quicker then I would with the 150 hp. It was a huge improvement on floats.

Mark shared a theory that Penn Yan installations of -6 degrees, pitch the engine down so much that the thrust is actually pulling the nose down at slower speeds giving it that "heavy feel".

He also said that the Charley Center STC uses about a -2 setting, and is thought to be a better performer then a stock Penn Yan. If you have one of these you wouldn't want to use the TL kit.

I have two cubs. A 150 hp 18A with stock wings which is really nice and flies great. The 180 hp has squared wings and long ailerons. If I sell one of them it will be the 150. This 180 18A is "hands down" my preference!

If you have a 180 hp engine that you think is really nose heavy; you may want to check into the trust line change.

That's the most useful post I've seen on this site in a long time. I have a new homework assignment!
 
Dave
When you say the 0320 flys slower, are you talking stall speed? Or attitude on approach (see it, feel it)? With Dougs math we added roughly 50 lbs. How much does that really effect stall speed? Things to ponder, still snowing.
DENNY
 
Just for discussion. Please describe your 180hp Cubs. Thanks

1960 PA-18A Wings are squared off after tossing the droop tips in a dumpster. Extended ailerons to the end. Standard flaps with 3 notches, Standard tail, Micro-air VGs. It does have an extended leading edge but that should not be a factor.
1200 lbs on 8:50/6 tires. EWCG is forward. Battery under the seat. The forward CG works well for me as I am always packing some sort of load.
Penn Yan conversion, Dynafocal mount. Rear cooler. 82/42 fat prop.
 

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CCenter 0-360
bal tail
3” extended gear
31” ABW
cargo Pod
extended wing
droop tips
std flaps ailerons
extended baggage
8242 prop
1331 EW
Big tail wheel

flies great but not like my old Stock 0-235 cub
It needed lots of trim adjustment but would land slow and T/O quick.
But then again if I fly this with no flaps needs lots of trim too.
But different performance from the stock bird too.
 

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In my experience flying different 18's in different engine configurations, if you have a 150, the 160 upgrade is the way to go unless you are operating on amphibs with 70 gallons of fuel and your 305lb brother in law in the back, and are often "heavier than you should be". That is where I feel the 180 really makes a distinct difference.

The heaviest nose (or lightest tail as it were) super cubs I have flown were Donald Jack's and Mark Drath's. I was afraid of the brakes in either of them - something that usually does not bother me - even if others say it is "nose heavy". Mark's is non-electric and under 1K on skis.

As to the performance math and fuel burn, if's all about % of HP as to how much it will burn for that engine. We all know that dialing it back will save money, but if you are the 150hp 40" pitch fixed prop guy with a bunch of constant speed 180's, they are probably going to use less fuel.

sj
 
Just to stir the pot, I've flown several J-5s with 0-235s, they were decent but just so so. Then once I was asked to ferry a no interior 85 hp J-5. That airplane was amazing, very short take off and landing distances without effort. Similar to a J-3. That airplane sat around never flying again. The owner took the wings off and took it home. Later he went west and I've heard nothing about the plane since.

I've heard a similar account from a guy that flew a J-3 for years landing at his cabin on a 400 ft strip. He bought a PA-11 thinking the added power would be better as they are the same basic airframe. He said that he lost performance. He then realized that the 11 had the engine thrust line changed. He started playing with spacers on his PA-11 mount to raise it back up and the result was a great improvement. I have heard rumors that there are several PA-11s out there with J-3 mounts.

I suspect that there may be a similarity with the J-5 series when they upgraded to different engine options.
 
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