" OK Cub .074 Performance Numbers?"


 

              


I am think about buying a couple of .074 Cub engines. I have only owned 1 OK Cub .049. I was very unhappy with the power that engine had. I can honestly say it was one of the lowest porer .049 engines I have ever owned.

If you own or have owned a Cub .074, or know anyone that does. Can you give me an Idea of what kink of rpm I can expect running a 6x3 prop with 20% nitro or a 7x3 prop.. Would one of these engines for example run better or worse than a cox sure start..

Any help would be appreciated. Thanks

I never saw a Cub at any size that could match to Cox engines.  They all seemed to be wimps, although the 14 was easy to start and easy to get a needle on, it was more like a Cox Queen Bee in power output (a Medallion 09 would blow it away).  I tried several OK 049s, the 074, and the 09 back when Herkimer used to run their back page ad every month on Air Trails (mid-1950's). 

However, some people had better luck -- Larry claimed to do so, and so did Currell Patty (hmmm?  has Currell ever put in an appearance here?)

Very cool plane Morgan!! The balloon tanks are the best, good luck in your event...

No, the balloons are usually 12" helium balloons, and do NOT provide pressure fuel draw.

Recently, I have been experimenting with very thin Polyethylene bags for the "balloon" and haven't had total success, but very encouraging results.  More as I learn.....

Thanks for the encouragement Ray!

The balloons I'm using are 7" with the
neck cut off to shorten it.
I made these tanks using the hard
plastic tube that comes with Sullivan
tanks. I slipped 1/2" of sillicon fuel line
onto the tube where I wanted to bind
the balloon. I used one strand of copper
wire stripped from 14 ga muli-strand to
bind the balloon to the fuel line.
A drop of CA on the wire for luck.
No leaks so far!

   A bit off topic.
The canopy was made using the
Hot air gun/ mineral water bottle"
technique. It took less than 20 minutes
to carve the pine mold and make the
canopy. It's perfect!
This has got to be the slickest technique
I've ever heard of!

OK, I'm writing this after the Balsa Beavers
Musciano event Sat morning.
  The Mustang won 1st in Stunt and
second in Concours.
  I managed inside loops, lazy eights,
sustained inverted and a reverse wing over.
Not bad for a '50's OK Cub!
  Mr. Chris Brownhill placed second with
a Blackhawk Little Devil and a new
Herkimer/Blackhawk OK Cub "A" with
the red plastic tank. His engine has
considerably better compression than
mine. I assume that the new engines are
assembled with more care these days.
The Little Devil has a tiny wing but the
Cub yanked it through two consecutive loops.
Very consistant runs. (Great pilot too!)

It's worth noting that all of the other entries
had Cox Black Widows. Everyone was amazed
what the old OK engines can do!