New build of Blackhawk Demon

[kenneth cook]

            My son and I finished this plane in January of this year and was able to fly it on a fair day in February. Building this plane was fun and I was very undecided on a engine. I was finding that the majority of combat engines I had was leading to a severe nose heavy condition. I was also concerned for the structure itself so I decided on a Russian combat .15. I chose the Stels.15 which I feel is a cool looking engine with its twin horn exhausts. The plane is flying quite well. I had to add additional tip weight and this seemed to make the plane a lot more stable. The plane was trying to roll in while upright and inverted. I chose Phil Cartier SLC covering which was pretty easy to use. I used Nelson water based polyurethane for the additional pieces. This is our first attempt at picture taking so here goes. Ken & Shawn

[Osni Renato]

Very Nice !
I love combat .
Congratulations

Regards  Osni

[Marvin Denny]

  Ken, Are you running bladder or Crankcase pressure?  I built one of the forst ones thast they came out with and put it on crank case pressure.  Really I built the tank  (metal one) so it could be standard vent, Uniflow, or crank case pressure.  That was for testing.  It was first flown on standard venting and then on uniflow.  The performance was pretty good for standard draw fuel but we had a warp in the wing and we had a lot of trouble getting it out.  We finally gave up and put a tab on the outboard wing and eliminated the trouble.  We used silk covering and the engine is a Fox blackhead combat special ( 1957 version) with a venturi restrictor in place.   Then with the restrictor still in place, we went to crankcase pressure and it really came alive--- even with onlt 15% nitro.   Now if I can get my test pilot to pull out the restrictor and go to 25  or 35 % nitro---- HMMMM  should be fun.
  I am going to build a Carl Berryman designed Phantasy next and put a Fox 36XBB on it and with Bladder pressure.

   Bigiron

[kenneth cook]

            Marvin, its probably hard to see the bladder compartment in the right forward wing area. I constructed the tube as per the plans using a paper towel cardboard tube with balsa ends. This was a bit tricky due to the thin airfoil wing. This was another reason why I used the .15 size engine due to the small compartment. The plane moves pretty good although my son claims its turning far better one direction than the other. We will work on that. This is being used for fun and excitement. We recently progressed to a Flite Streak with a Fox Mark series on bladder which is pretty cool. I think its the noise as it comes on after a lap. You really have to have an admiration for piston powered engines. Ken

[Lyle Spiegel]

Reading about your plans to use a bladder setup- I've got a new Sneeker kit -have not decided if I will use my Fox 36XBB or J CS- need to decide between bladder or hard tank- where can I get details of how to setup a bladder properly? I have an original hard tank set up for Rat Race with the rubber "quick fill" - rubber is all dried out- was planned to be installed on a Goldberg Scat Rat- is this style tank still available- I believe it was sold by same folks who sold  hard rubber "Don's" Racing Wheels.
Thanks

[Kim Mortimore]

........The plane moves pretty good although my son claims its turning far better one direction than the other. We will work on that....... Ken

Ken,
You may already know this, but for anyone who doesn't.....  Sounds like either you have some upthrust or downthrust, or the bellcrank is not parallel to the ribs at neutral, which will give you both quicker control and more control in one direction than the other.  An easy test for bellcrank neutral when you can't see the bellcrank is to compare the stabilitor angle at full Up with full Down.  If they are not equal, the solution is to adjust the pushrod length.   Keep us posted, Ken.  Nice plane!

Happy Flying,
Kim Mortimore

[ray copeland]

That looks like some cool fun Ken! I am looking for a home for my Norvel AME .15, this may be the bird. 

[kenneth cook]

       Ray, just for the record, I love my AME Norvel .15. I did have a problem with it though which took some serious life from the engine. My son unlike myself can surely fly these models better than I can. He has flown a few matches with some of our clubs top flyers. These two aren't looking for competition, just fun times. One thing I noticed that happens is when the other guy cuts the other streamer the game is on. It seems that you get very caught up in the moment and some real close calls to the ground tend to result. In our case it was other individuals plane, which was mine. The Norvel has a stud for the prop screw which is considerably smaller than the shaft itself. It seems that they're also hardened more than they need to be resulting in it breaking off. This was probably the most horrific sound when the engine went into what sounded like + 30k rpm's. It then virtually welded the con rod to the crankpin. It ruined the bearings and degraded the piston sleeve fit. The engine still runs though and I love it. It took a bit of polishing to get the con rod back into shape. I run mine on bladder in a foamie wing and its a blast. My advice is to switch that stud to a lesser grade bolt and let it be the sacrificial element. I use APC 7x4's and let it wind away. Ken

[LARRY RICE]

Ken & Shawn,

     You did a very nice with your Demon and I am sure that it will provide you with many hours of enjoyment. We have just reworked the Demon kit and now offer it with a one piece wing and full size plans. In the coming months we will be releasing two new slow combat models, Mongoose and Apocalypse. We also will have a junior  size wing designed for .15 engines caller Diamond Lil.
Thank You for your support 
Larry
Black Hawk Models