Backcountry Pilot

[msd7ac offline]

Wondering if anyone out there has done the Wagner stc for the o-235 or even the o-200 in the champ. I am wondering what the performance specs are. Is it worth it? Also has anyone put the 29" LSA tundra tires on one. Let me know thsnks

[Bighorn offline]

Wait for WWHunter to reply from up here in Minnesota.......he has a Champ with both of them.......a sweet machine.

[WWhunter offline]

Here I am..Here I am!!!
Yes sir, as Bighorn states, I own a Champ with an O-235 and when its not on floats it is on Bushwheels.
Before answering any questions I will be up front and state I have ZERO time in a bone stock Champ. I bought this Champ with the engine already installed and bought it strictly for my own personal float training/flying. The Bushwheels are great on it, although I only have the 26" Airstreaks on the plane. There are a few guys in Alaska using the 29 and 31's on their Champs.
The thing you will notice with the O-235 is the plane has a nose heavy feel. Nothing you won't adjust to fairly quick, just something I noticed when I first started flying the plane. The engine turns the Champ into a good performing plane, granted its not a Super Cub, 180, etc. but sure makes it a fun plane.


Keith

[Super11 offline]

I recently did a climb competition with a Rans s-7 that had Lycoming's new 0-233. My exp cub has a C-90 with the c-85 pistons. My cub got off quicker and stayed above the rans all the way up .
Now to be fair I have to say that the rans is heavier than my cub and the cg is slightly past the forward limit. (he adds ballast when flying solo) All in all I would look at souping up an 0-200 as they are significantly lighter than an o-235. Just my 2 cents. Clint

[skyjeep offline]

Or go with the C-90 rather than O-200. It has more torque, higher HP at same RPM. Actually performs better in real world. O-200 needs a flatter prop to get the power at takeoff and then when you pull back the throttle for cruise it has less power. C-90 can run a coarser prop. Can't recall the details now, but think it has longer stroke. If you can find the Luscombe email archive I know there is a lot of info on these engines. I had a Luscombe with O-200 some years ago.

[hotrod180 offline]

It's my understanding that the C90 & O-200 are the same basic engine with different cams-- bore & stroke (and therefore displacement) is the same. The C90 can swing a longer prop & develops it's power at a lower. Don't know the cam profile for the C85 but I assume it is closer to the C90 than the O-200. So a C90, O-200 with a C90 cam, or a C85 with the "stroker" crank mod would be the ticket.
235 Lyc's have more power but quite a bit of weight comes along with it. Lightweight starters & alternators are available for both the Lyc & the Continental now too. Converting to an O-200 from a 65 or 86 might not even involve a new engine mount, as opposed to a Lycoming conversion which would definitely need one.
The Lycoming & Continental engines have different weak points too- the Continental's (valves seats & guides) seem to develop problems from flying it and the Lycoming's (cam & followers) from not flying it.

[msd7ac offline]

Thanks for the great info, I have started to narrow my search to the c-90 or c-85. I get fine short field performance now, so mainly am looking at conversion for climb performance. Before annual it took forever to get to 2500 feet. I really would like to fly it out to the caveman fly-in. Wouldn't think about crossing those mountains with only 65hp. Let me know if anyone else from east coast is headed that way.

[hotrod180 offline]

I've seen Champ engine upgrades done by "converting" the 7AC to a later model, like the 7BCM, using just the TCDS as a basis for approval-- basically drop in a C85 & modify the airframe data plate to read "7AC conv 7BCM" or similar. That way you probably have to go with a non-electrics dash-8 (but I'm not sure on that)-- maybe add a field approval (if required) for a dash-12 engine if you want a starter, etc. ( BTW that C85 just might happen to have an O-200 "stroker" crank in it )
There are probably also STC's available, or prior field approvals you can use as "accepted data" in getting your own field approval. You could also convert to the CCM or DC model Champ with a C90, but I believe these have a larger vertical stabilizer and maybe some other added features so conversion and approval might be a lot more involved.
There's a pretty good aeronca discussion site where you could probably get some good info on this sort of thing.

[Max Torque offline]

There is a Service Letter (more than one, actually) that addresses converting to a bigger engine. Fairly simple and no STC required. http://www.joea.com/phpBB2/viewtopic.php?f=15&t=4790 has a pretty good thread on converting.

[hotrod180 offline]

There is a Service Letter (more than one, actually) that addresses converting to a bigger engine. Fairly simple and no STC required. http://www.joea.com/phpBB2/viewtopic.php?f=15&t=4790 has a pretty good thread on converting.

Brief but very informative discussion from about a year ago-- well worth looking at for anyone thinkiing of re-powering their Champ.

[BRD offline]

One showed up locally this month.

[CamTom12 offline]

One showed up locally this month.

Short thread hijack...

BRD, I want to come visit and arrange an air-to-air photo shoot with you one of these days. Your pictures are amazing!

/hijack

[BRD offline]

Sure, anytime!

[contactflying offline]

I liked the Champ with the C-90 best in the desert and mountains. I had several C-75, and C-85 engines that ran pretty hot all the time in summer. The C-90 was powerful enough and ran slow and cooler.

[Tom offline]

I sure would like to put my old champ on a diet. At 1035 empty with a c90 it was kind of fat. My Supercub on 8.50's weighed 1034. What a difference.

[JimC offline]

Below 9000' DA or above 21" MP, the C90 has less torque than an O-200.
Peak Sea Level horsepower for the C90 is at 3000 rpm, where the C90 puts out 99 hp vs the O-200's 107 hp at that rpm.
Peak for the O-200 is considerably higher than 3000.
Sea Level Torque of the C90 and O-200 is closest at 2625 rpm, where the C90 puts out 188 lb-ft and the O-200 puts out 192.5 lb-ft. The O-200 does even better relative to the C90 as the rpm diverges from 2625 in either direction.

Above 9000-9500 feet, the advantage shifts to the C90.

C85 cam profile is closer to the O-200, but valve lift is only 0.381". C90 and O-200 valve lift is 0.410".

[3454terryg offline]

Here I am..Here I am!!!
Yes sir, as Bighorn states, I own a Champ with an O-235 and when its not on floats it is on Bushwheels.
Before answering any questions I will be up front and state I have ZERO time in a bone stock Champ. I bought this Champ with the engine already installed and bought it strictly for my own personal float training/flying. The Bushwheels are great on it, although I only have the 26" Airstreaks on the plane. There are a few guys in Alaska using the 29 and 31's on their Champs.
The thing you will notice with the O-235 is the plane has a nose heavy feel. Nothing you won't adjust to fairly quick, just something I noticed when I first started flying the plane. The engine turns the Champ into a good performing plane, granted its not a Super Cub, 180, etc. but sure makes it a fun plane.


Keith

what kind of float performance did you get with the 0235?

[WWhunter offline]

What type of 'performance' questions are you wanting answered? It had no problem hauling a load, although the time to get on step and off the water would be much longer than flying solo. It would top out at just over 100 mph on the PK 1500's.

I flew it in and out of my 1000 ft strip nestled in the trees, flied elev. 1500'. The only complaint I had with the plane, the drum brakes were barely marginal when I had it on 26" Bushwheels.
I may not be overly helpful with precise numbers due to having sold the Champ a few years ago. I put 300+ hours on it, mostly on floats and had a blast. After my son graduated from ERAU and was commisioned into the AF, I lost my flying partner. The year after he left I only flew it occassionally, so I decided to sell it. I really regret selling it!!! Cheap to own and maintain.