Maybe I can help. What do you want to know?
Larry

  I am in the process of building and evaluating one right now for the New Products column of CLW mag.
  I think that a good 25 will pull that plane just fine.  The plans show a suction metal tank fuel system, but also show a bladder pressure system if the builder so desires.
  I am going to set this one up for metal tank but use crank case pressure.  I will probably make the tank so I can use EITHER open vent  OR case pressure.

   Bigiron 

 Bladder is definitely simpler, lighter, and more trouble free tham crankcase pressure.
  I may clone this one to  permit trying bladder and a few other mods.
  Bigiron

  PS  I had two quite long phone conversations with Riley Wooten on the subject of the Demon and  diamond airfoils.

  B

I flew Demons for one contest season back in '67--yeah, I know--makes me an old fart. Used needle bearing Fox Rockets on them, with doubled pen bladders.

I found the Demon flew--well--differently as compared to either the Sneaker or the Voodoo. The Demon would snap very sharply into a turn, either direction, then skid badly if the turn was held. It wouldn't stall, as in an over-controlled situation--just skid until you changed directions. In my opinion this was due to the diamond airfoil. Dan Pattons' Eliminator displayed the same characteristics.

I think todays Demon with a .25 would make a fun sport plane to have some fun with, but think a Sneaker would be a better plane.

Thanks for the input guys,will update on progress building and first flight by my retired pilot.

I built a Flite Line Demon in 1973.

Quite a story.  I had just returned from SEA and was living in an apratment with zero building faciliites.  I had won the kit at contest a few years earlier. 

My new flyng buddies told me the airplane was obsolete, undersize, and didn't have a chance against a Motivator or a Nemisis.  I said, "maybe so, but it't the only kit I've got right now."

At the contest, the Tangerine in Jacksonville, I won the first round and lost the second.  The "Motivator guy" won both rounds but used up all his toys. 

I loaned him the Demon and he went on to take second place and wreck the model.

Despite freak success, lesson-learned.  I never built a plane that small again.

In retrospect, it was a short, sweet modeling experience.   A lot of planes don't take a second place in a much longer life.

No-one's are.  I was flying a combat wing this fall and actually lost it in the air...it turned so fast out of my field of vision I wasn't sure where it went; had to resort to flying by feel until I could locate it again.  Made me feel pretty foolish, looking wildly around at the sky trying to find my own plane. 

I built a Demon off scaled-up magazine plans in the 60s.  It flew OK, I used it in a few fights but wasn't that impressed with it.  No better than an early short-tail Voodoo; not as good as my Vampire (until it folded up in midflight as all good Vampires do). Several designs of the era were better fliers; the Demon's strongest point was its ease of--and speed of--construction. Pretty hard to build a warp into it with those flat ribs. It did slide some in hard corners.

--Ray

P.S. I don't mean to knock Blackhawk Models kitting the Demon; very nice for nostalgia.  I wish they'd re-kit the early Voodoo too.  These were classic designs, even though other designs could fly circles around them. Rush's Nemesis was probably the acme of that particular design era. 

All the above IMO of course.

I understand and concur wholeheartedly.  Carry on!

--Ray