If you had two PA-11's and all things being equal, other than one had a C-85 and the other had the C-90, would there be a noticeable difference in performance between the two Cubs? I have never flown either, and I have nothing to compare the two motors to.
Thx, RD
The performance difference is going to depend on the propeller and engine condition but all things being equal the C90 should perform better than the C85. IMO the C-90 is the sweetheart out of the small Continental lineup. Makes nearly as much power as an O-200 but at a much lower RPM. Lots of torque so you can swing a long prop efficiently.
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I owned a C-90 powered PA-11, that C-90 is a torque monster compared to other small Continentals.
MTV
The C-90 has more displacement than the C-85 (201 vs 188 ci), higher compression (7.0:1 vs 6.3:1), and similar camshaft timing (within a degree) but more valve lift (0.410" vs 0.382"). With a free flowing intake and exhaust both perform well. The C-90 a bit better with the same long propeller.
Gary
but if you have a chance at a 11 with a 85 or even a 65 at your price, dont turn the other way by anymeans, not that easy to find any more. lotsa things can be done later.
With the right STC and $$$$$ a C-85 can be modified into a C-90 clone
https://www.supercub.org/forum/showt...ance-questions
Gary
That's a great point and the purpose of my original question. "Is the C-85 a deal breaker"? If I talk the Alaska guys, I'm told to wait and get the C-90 - that I won't be happy with the 85. And although nobody that has responded here is saying it in those direct terms, that is what I'm hearing - "get the C-90".Originally Posted by tempdoug
All good info!! Appreciated!!
When you'll need power is on skis or floats. And at high density altitude. But airframe weight plays in the game...a light PA-11 with a C-85 vs heavy one with C-90/O-200 will perform very well. All engines like a low restriction intake and exhaust for performance. The PA-11 isn't particularly one in my experience of owning. The same engine in another aircraft may perform better.
For example a fresh C-90 in a PA-11 with stock exhaust turned the same (I just switched props) Sen AK76-2-40 prop about 2325 static vs 2425-40 with a C-85 Stroker in my current Taylorcraft (optic tach). I have a low restriction C-150 exhaust plus low restriction Donaldson air filter oil and overhauled tight airbox (minimal carb heat leaks).
Never pass up a sweet flying airplane just for the promise of more power in a heavy dog.
Gary
"Never pass up a sweet flying airplane just for the promise of more power in a heavy dog".
That's great advise Gary. Every PA-11 I've considered is different. Some have no electric, some have too much electric.... I've looked at some that have only one 12 gallon tank, some have 2 twelve gallon tanks. There's a few that have 36 gallons. Some say they weigh 820, others say 875. I'm always suspect of documented weights. And on top of all the confusion, all of these cubs are in the lower 48...
My search continues...
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So, are you actually LOOKING at a particular PA-11, or just "shopping"? As Gary noted above, don't pass up a really light airplane with a C-85 to buy a heavy one with a 90.
Also, check the prop ANY of these are equipped with. It seemed to me when I owned one that most folks believed that just any old prop that fit on a Continental was "approved" on a PA-11. Check the TC and look for STCs.
MTV
Hey Mike - I am actually looking at a couple 11's in the lower 48. The one with the C-85 is an absolute cream puff, recently finished total restoration. Said to weigh 855. As it sits, it is a completely stock configuration with 12 gallons of fuel. Bring to Alaska and put on heavy gear and 26" / 29" light weight Airstreaks - Scott 3200 tail wheel - now what will it weigh - how will it fly? Still would need 12 more gallons of fuel for Alaska - IMO???
If I had my "rathers", I think I would rather have a 18-95, but they are harder to find than an 11. It's not like they are giving these little planes away either!! Without fail, everyone I've considered is between $65 & $85K. It's hard to make a good decision on any Cub when I'm in Alaska and these cubs are in the Lower 48.....
Good Question. A possibility I mis-understood. Could have two 12 gal tanks, which I've seen in other 11's. I will check..
We've discussed this here so try a search for more, but with a GW of 1220 conventional and 1350 floats a PA-11 needs to be light. For a test, run your typical flight plan for distance and load package with reserves for weather. Like where would you expect to travel in Alaska with useful load and available fuel? Would you be pleased with the airplane, and how much fuel would be needed. Could you grow with the PA-11 as is, or would you need to overload..exchanging one flight error for safety to prevent another.
I'm serious about this. Don't someday place yourself or passengers in a load or range limited airplane if there are other options now.
Edit: When I had my PA-11 N333GP my needs were to fly a 200 mile roundtrip plus winds to a remote camp. The dog could go but not the wife and dog without refueling. That's reality.
Gary
"Edit: When I had my PA-11 N333GP my needs were to fly a 200 mile roundtrip plus winds to a remote camp. The dog could go but not the wife and dog without refueling. That's reality.
Did your 11 have the C-90? What were you burning per hour?? Typically can you get 5 gallons an hour or is it less than that?
Refresh my failing memory, what's the GW of a PA18-95, 1550??
I'd burn 6 on floats with the C-90 at about 85. Less on conventional gear. TCDS 1A2 for the PA-18 shows 1500 GW conventional gear, varies depending on type floats (factory approved or STC'd) if installed.
I'm using approved GW. Some don't and create issues later.
Gary
C-90. 5.5 an hour with the Stromberg. Great torque and a delight to fly.
The biggest issue I see is folks trying to morph a PA-11 into something it shouldn't be. Which turns it into something that is not such a pure delight to fly.
Anymore, 90% of my flying will be solo, just punchin holes through sky, mountain flying looking for sheep, or gravel bar hopping. Bad knees, rebuilt shoulders and a sore back limits my desire to pack big moose out of a swamp, but I do believe I have a few good sheep hunts left in me. I am fairly certain I can accomplish that in a PA-11, and certainly in a PA18-95.
I would love to be asking these questions about a 18-95, so if anyone knows where there is a good one for sale, I'm all ears!!
Thanks for all the input gents!
My -11 was equipped with a Marvel Carb, with mixture control. My base is at 4500 msl, so the ability to lean was nice. I flight planned 6 gallons an hour, which was conservative.
MTV
I'll chime in. I don't have a PA-11, but a Commonwealth Skyranger 185. It came from the factory with a C-85, but 40 years ago someone put in a C-90.
I've talked with other folks with the Skyrangers with C-85s. It looks like I get a little better rate of climb on high density altitude days (with appropriate leaning), no real difference in cruise speed (90 mph), and I burn around 5.5 gph at cruise.
But I tend to like to fly at low power settings getting around 80 mph at 4 gph.
It's a nice engine for my purposes, but I wouldn't turn my back on a C-85, either.
There's something fishy about a PA-11 with a "12 gallon tank". A 12 gallon J-3 tank is installed in the fuselage in front of the front seat occupant. It will not physically fit in a PA-11 fuselage.
All PA-11s came from Piper with a 17 gallon tank [NOT an 18 gallon tank]. About 9 months after production started in April of 1947, an AD was issued mandating the installation of a header tank installed in front of the instrument panel. This was due to fuel unporting from the pick up at the aft inboard of the tank when the airplane was in a long glide with less than five gallons of fuel aboard. The header tank resulted in nearly 18 gallons of usable fuel capacity for the airplane. The main tank capacity was still 17 gallons and is placarded as such. Airplanes that were produced after the AD was issued got their header tanks installed on the production line, but fuel capacity for a PA-11 is still listed as 17 gallons unless the airplane has been modified.
That sounds like a very nice machine.
Umm......I think I saw some TP fall out
Glenn
"Optimism is going after Moby Dick in a rowboat and taking the tartar sauce with you!"
The guy that is advertising the Cub is the grandson of the man that built and owns this -11. When I asked him about the fuel capacity, he said, "12 gallons in the wing tank, but I need to verify". I reached out to them today to verify, but have not heard back yet.
Another obs is the wing. I flew my PA-11 with both standard config, and extended with droop tips. On floats I preferred the latter, but that was after I removed the long wing extensions during a rebuild. I also added flaps which was a +20# error.
I mention this because wing area can help correct for some power differences on takeoff and climb. If the PA-11 has an 85 and you're not pleased, think some about the wing before redoing the engine and then weigh the +- benefits.
Gary
My PA-11 had the stock left side 17 gallon tank and a Biplanes, Inc 12 gallon tank in the right wing. Very nice for longer range.
MTV
The 90’os my favorite small Continental but it’s not easy to find. My experience has been that it runs smoother, performs better, and burns less fuel than the 85. Some of that is explainable and some of it may be differences between individual airplanes and engines.
I wouldn’t turn down an 85 hp PA-11 (I mean, I bought one after all…*), but if you have the option for a 90 and the airplanes are otherwise similar in quality? Get the 90. Otherwise, have fun with the 85 and do like I’m going to, which is watch for a C-90 engine to buy some day.
* Technically, mine is a J3 that dresses up as a PA-11.
—Amy
Sent from my iPhone using Tapatalk
Proud owner of a collection of airplane pieces (sometimes in one big piece) known as the Oklahoma Kid.
Ours was pimped - out with -18 fuel system, tail, and flaps. It got too heavy, no useful. Still flew nice at sea level with the C90. That Sensenich 76AK-2 is what you want unless you can get approval (or you’re experimental) for a fixed CF prop…probably a Catto or MT. MTV is right, there is a lot of gamesmanship played with props on those.
As other posters have noted, this sounds like an experimental/amateur built Cub with a 12 gallon wing tank installed. I can't imagine someone modifying a standard category PA-11 to carry less fuel than the original.
Nope, it's a certified 1947 PA-11. I think the young man I spoke with just did not know what the fuel capacity is. This one is hard to resist - the restoration is spectacular, but I think it is heavy as it has full electrical system. There is another in the Pacific Northwest that has the C-90, no electric and comes with Bauman floats. Say's it's 820bs on wheels...
I hand propped my PA-11 for 14 yrs year round. On floats too. If the engine temp was cool to cold forget it despite dual impulse mags, dual cylinder primer, and a Marvel carb.
"Bad knees, rebuilt shoulders and a sore back limits my desire to pack big moose out of a swamp, but I do believe I have a few good sheep hunts left in me" Consider trying hand propping before buying. However, if the C-90 is a -12 with block off plates for the accessory case a starter and battery could be installed to help. Just a thought.
Gary
Also, consider overall accessibility. Getting in and out a PA-11 is a coordination exercise. And even with conform foam on the seats your duration aloft has limits in the comfort department. I wound up with my first J-3 because the owner had hurt his back and getting in and out was difficult. I, myself, have noticed that after I lost some weight getting in and out of the -11 was a bit easier....
JP Russell--The Cub Therapist
1947 PA-11 Cub Special
Switch gears a bit here.... I've been looking at a pretty nice -11 in the Portland OR area. C-90-8F on Bauman 1420's. He will sell without the floats. Does anyone have a recommendation on mechanics for a pre-buy?
If it is pretty nice and priced correctly I would go look at it rather quickly with cash in the overnight bag. Yes, take a mechanic with you who knows paperwork, and do a title search.
Good ones priced correctly are gone in a week.
Opinion.
And borrow if necessary to buy the floats. Get them to Alaska, and if not needed, sell them for a profit if priced reasonably to begin with. They are rare and desirable come float season.
Gary
Hmmm, interesting. I can afford the cub with the floats, just was not interested in float flyin. They are tight and in good shape. What do you think they are worth - aproximately?? He told me they are north of what I've seen a good set of Edo 2000's are currently selling for.... I have my doubts, but I'm not a float guy.
I know they are valuable. They are worth more than average EDO 2000's in my opinion. The rigging for a PA-11 or -18 is not available and also valuable. We shouldn't talk prices on an open Forum as that may influence all involved. I'd buy them tomorrow if they fit my Taylorcraft but the rigging's different.
So, if you proceed ask others down there that do floats in confidence about their value. They made 1420's and 1500's. I believe (correct me if wrong) one is longer than the other (the 1420's?).
Or....maybe it's time to become that guy that flys floats? Once you do you'll throw rocks at the other gear.
Gary
You're alright Gary! My dad and sister live in Fairbanks. I will have to come visit you when I'm in town..
Check your PM's
I'm replying. Send me your E-mail and I'll send a PFD that describes the 1420 floats and a flight test.
Gary
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