• If You Are Having Trouble Logging In with Your Old Username and Password, Please use this Forgot Your Password link to get re-established.
  • Hey! Be sure to login or register!

O540 in a Super Cub

Seems like once years ago at the Arlington fly-in I saw a 540 on an exp SC from down around Sandy Oregon.
 
There was one featured in one of the magazines (can't remember if it was AOPA or Flying) several years ago. Maybe even 15-20 years. I think it was black and used as a glider tug. I remember the owner said he had to watch the climb angle due to fuel starvation if it got too steep.
 
I flew one that was done years ago, was for sale so tried it out. Believe done originally in Oregon, but was in Kentucky at the time.
Did not have the cub feel, was pretty heavy, smooth and lots of power, but just too heavy and felt too different than regular cub to me, so I passed on it. Just heavy on controls and felt that way in most respects. No acceleration you would expect with the power, weight was the key.
John
 
I would move the wing forward to balance the plane out. That alone would help allot with the feel of the plane. Then if you chose to run a controllable prop you get all the power it could make quite a workhorse.
Not having really looked into it the upper part of the firewall could come back some to tuck the engine in as well.
 
changeover.jpg

300 HP IO-520 C originally from Beech Baron
 

Attachments

  • changeover.jpg
    changeover.jpg
    139.8 KB · Views: 338
Might not be fair to judge the airplane on that take off. I don't think flaps were even used. Didn't look like he tried too hard.
 
Thanks for the links! I like the idea of a 6 cylinders since they tend to run smoother. Some of the O540’s produce 260 HP. I would only consider a fixed pitch prop for weight.
Have you considered the Continental IO-360K? It is rated at 195 hp in the Hawk XP but is allowed up to 210 hp with the proper prop.
 
All that weight on the nose? watching stall tests would be more telling than takeoffs. I have a big motor CG riddle with a 390 and my plane’s airframe is extended. I can’t imagine a 540 being useful. Heck, lots of guys hesitate to put 360s on for fear of nose heaviness. PA-12 long mounts demonstrate that as well. CG is critical for a well behaved airplane. What do these big 6 cylinder Cubs add for ballast?
 
On a much smaller scale.... I used a Subaru conversion in my first S-7, about 40 pounds heavier then the Rotax I used in my current. It worked great, and was totally reliable for 1300 hours, until I sold it. BUT, even ballasted out (13 pounds of lead in the tail cone, not to mention aft mounted battery,tool kit, and all the other tricks to get the CG aft) it still only flew nearly as good as my new one when i was carrying a passenger or lots of baggage. Yes it was 15 more horsepower then the 80 horse Rotaxs back then (before the 100 hp version came along) but it taught me a lot of the effects of extra weight in the nose, even when CG corrected on paper to make it balance out.

At least they used an appropriate yard crane to handle that engine! That got a chuckle out of this crane operator/lighter is better guy.
 
Met a guy at Minem lodge (way back when) who flew one in. Said it wasn’t really worth it.
 
I think it would fly like a a crowbar. Makes me recall watching a 600 Stearman land at an airshow years ago. He appeared to come over the fence with the stick all the way back and flare with the throttle.
 
Back
Top