Looking for someone who flies a Brodak 40 with .280 venturi and stock NVA; how much fuel to fly the pattern?   Trying to plan for tank size on new build.  Thanks for any help with this!

   Hi Bill;
   A stock Brodak .40 , when new or low time, can be a pretty thirsty animal if running 10%. I would plan on at least a 5 ounce tank. They get better as they get more time on them but it does take a while. My first experience with them was when they first came out. I have a profile model that I was running a FP-.40 on with a 4 ounce tank, and just switched engines. I went to the SIG contest with it and didn't get a chance to test fly it at all, and imagine my surprise when it ran out of fuel ( a full 4 ounces) at the overhead 8's!!  I think I was able to stuff a 6 ounce plastic tank on it that worked well right off the bat and is still on the airplane. If there is room for a 6 ounce Sullivan RST tank, I would go that route so you know you will have plenty. Other wise see if there are any 5 ounce metal tanks on the market or fabricate one.
    Good luck with it!
  Type at you later,
   Dan McEntee

I had trouble with the stock NVA assembly.  I could not get enough pinch to secure the needle from rotating due to vibration.  I replaced it with an ST unit but that should make no difference as the spraybar diameters are the same.

I am using a .290 venturi and I never needed more than 5% nitro.  In cooler weather, 2% is good enough.  My fuel consumption with those two nitro percentages varies from 3.5 ounces to almost 4.  I am using the supplied tube muffler.  I get about a minute of run time after the clover.

This particular Brodak 40 does not have hundreds of flights on it but it is fairly well broken in.

   The Brodak 40 is a great engine! It will easily pull a 50oz plane through the patten with a 4-2-4 break. 59'.015 lines, Powermaster GMA 10-22 fuel, must be filtered before you put it in the tank. APC 11.5x4 prop, 4.5oz tank, Sig or Thunder bolt idle bar plug, Stock NVA & Venturi with 1- or 2-pieces of pantyhose covering the Venturi. Make sure you have a later Brodak muffler that has at least a .360 exhaust opening. A Fox 40 downward style muffler works great on upright engine setup.
Al

I had trouble with the stock NVA assembly.  I could not get enough pinch to secure the needle from rotating due to vibration. 

    That sometimes happens with the original ST spraybar as well. The problem was that the brass wore/flowed enough that the slot in the collet end of the spraybar close up all the way, so it was tightening on itself and not squeezing the needle. The fix was to take a razor saw, and open up the slot (cleaning out the chips afterward).

   No guarantees, but worth a look. A lot of the off-brand ST copies have various machining issues that make the not work or unreliable.


     Brett

Thanks, guys, lots of good info!