Stalker Engine Update 2.0 ****Correction In Red

[Jim Catevenis]

                                                                                                              March 2019
                                     Stalker Engine Update 2.0
        Fuel    
             I competed all of 2018 running my own zero nitro fuel, and plan to do the same
        in 2019.  The methanol came from the local speed shop (VP Brand in a 5 gallon
        container for $37.00) and Klotz Synthetic oil from Sig Mfg.  I ran 18% synthetic in
        all sizes of Stalkers.
             Some things learned: (A) All engines seem run 3 1/2 ounces of the above fuel
        for the pattern.  I cannot explain this, other than the .61 - .76 are simply more
        efficient.  (B) The engines run best on zero nitro as delivered, with the stock head
        spacing.  There is still plenty of power.  (D) The engines start normally except
        in very cool weather, under 50 degrees Fahrenheit.  A little lighter fluid down the
        venturi is helpful then.
        Needle Valve Assembly
              It is common for the stock NVA to leak a little air where the ratchet spring
         seats on the crankcase.  This does not seem to affect anything, but if it bothers
         you, it can be fixed with a dab of 5 minute epoxy under the spring to act as a
         sealant.  The epoxy is easily removed, when desired, by heating the area with
         the tip of a soldering iron to soften it.  The alternatives are to substitute an ST .60
         NVA, or to mill back each side of the crankcase .060”, and use a Brodak .40
         NVA.  (The Brodak .40 NVA is too short without narrowing the case.)
        Air Filters
              I do not recommend using any sort of air filter on the venturi.  If you do not let
         the engine run continuously on dusty ground, no filter is needed.  They cut
         power, and make the engine harder to choke anyway.  Do use a fuel filter.
         Venturis
                Venturis on .40 to.51 are interchangeable, ditto on .61 to .81.You can put
         a .40 venturi on a .51 to cut down the power some.  Jim Lee (Lee Machine Shop)
          in Topeka, KS, also has after market Delrin venturis available for Stalkers.
        Mufflers
              For side exhaust engines, the following common sizes fit:
                   Stalker .40, 46, 51SE = OS .35S/K&B .40
                   Stalker 76SE = ST .51/.60
          Tongue mufflers are available from Brodak, RSM, or Lee Machine Shop.

                                                                                                 Tom Dixon

       

[Ruslan Kurenkov]

Hello Jim!
Very good message.
It is very interesting to hear that you use 18 percent synthetic oil. We never tried to fly on fuel without castor oil. It will be necessary to try this season.
We always use 9 percent synthetic oil and 9 percent castor oil.
If you start badly in very cold weather, we do not add 0.5 ml of fuel to the engine before starting as usual, but twice as much. In this case, in cold weather, we increase the glow of the spark plug from 1.5 volts to 1.8 volts on the regulator and the engine usually starts very quickly.
Say a big hello to Tom from Oleg and Tatiana from Kharkov and a big hello from me personally.
I wish you and your customers a lot of good flights.
Regards
Ruslan