My question is this.  What makes this engine run so well right out of the box.  It is not a custom engine or has it been worked on by an “expert.” Do all of these engines run this well or did I just get lucky?

     Opinions/Suggestions?

     Frank McCune

    Opinion - this is exactly what I and several others have been trying to get across in almost every engine-based post you have made for the last 3-4 years. Now you begin to see a small indication of what we were trying to tell you. Note that the 46LA is also not really a competitive engine, either, but it's at least dead-nuts reliable and decently powerful by sport-flying standards.


    Key takeaway:

It is not a custom engine or has it been worked on by an “expert.”

     And, to add - you are going to *leave it alone from here out*, right?  Don't take it apart to see what is in it, don't "modify" it, don't "adjust" it other than a few needle clicks. Don't send it to an "expert", don't let the locals tell you all the tricks you need to "improve it". Put in gas, put on battery, flip prop, fly.

   That the 46LA is a pretty decent stunt engine seems mostly to be a coincidence, it is a low-ball RC sport engine, very inexpensively made and of relatively low performance by engine standards, that happens to give about the right power for running 4" or so pitch props at stunt settings. There are *many* much better engines than that - it's older brothers, the 40 and 46VF, are still "gold standard" and *much better engines* than a 46LA. They are not much better for an ARF Nobler, the 46LA is great overkill, but it is mild enough to make it work - *if left alone*.

 If you are comparing it to an HP, it will indeed seem like a miracle, because even when there were few other options, and before piped engines, the HP was very rarely used and the ST46 - also now greatly exceeded - was a lot better and infinitely easier to deal with. Neither HP40 was every much good for stunt, and while they have had a few good moments in absolute expert hands, as a general purpose stunt/sport motor, they are terrible. As you have proven.

   I am very glad someone took this issue in hand and showed you part of what you have been missing - basically demonstrating what I and a bunch of others have been trying to tell you now for years.

    Brett

     Hello All:

     My flying mate insisted that I power my “New” Nobler ARF  with an OS LA .46 engine in lieu of the HP .40 that I had planned to use. I think very highly of the HP engines for Stunt use.  I respected his wisdom and
and went with the OS.

      Upon arriving at the field, we fueled the tank, opened the needle valve three turns, choked the engine a couple of turns, connected the battery and back flipped the engine once the engine sprung into life.  Pete my friend, closed  the needle valve until the tach read 9,700 rpm. on a wooden 11-5 prop. The engine ran a four cycle in level flight and a two cycle in maneuvers.  A perfect engine run!  The plane flew perfectly also.

     My question is this.  What makes this engine run so well right out of the box.  It is not a custom engine or has it been worked on by an “expert.” Do all of these engines run this well or did I just get lucky?

     Opinions/Suggestions?

     Frank McCune

    And if you promise not to tell anyone, I'll let you in on a little secret. If you set up an LA.40 the same way, it will run just as good but with a bit less overall power and use less fuel. It really is over kill for the ARF Nobler. I have an old OS.35S in an ARF Nobler and it's just about a perfect fit. The problem with the ARF Nobler is getting a tank squared away. There is hardly any wood in the nose of the airplane and no traditional floor for the tank area. I put in 3/8" balsa planks with the grain cross ways between the tapered beams to make the mounts stiffer and provide a floor for the tank. The fuselage is so narrow that you can't get any 2" wide standard tank in it, so I made a custom tank to just fit the fuselage and can get 4 1/4 ounces fuel max in it. With the stock LA.46s I run, I don't know how you got a tank in it big enough to do the pattern? Most of main take more than 4 ounces, 4.5 more or less, to do the pattern depending on model and other variables.
  Type at you later,
   Dan McEntee

    And if you promise not to tell anyone, I'll let you in on a little secret. If you set up an LA.40 the same way, it will run just as good but with a bit less overall power and use less fuel. It really is over kill for the ARF Nobler.

  "Set Up" - "do absolutely nothing", I hope. And *it's working now*, why are we trying to fix it?

I have an old OS.35S in an ARF Nobler and it's just about a perfect fit.

   He just got his first-ever decent engine run with something else, my God, don't get him off-track again!

     Brett

  "Set Up" - "do absolutely nothing", I hope. And *it's working now*, why are we trying to fix it?


   He just got his first-ever decent engine run with something else, my God, don't get him off-track again!

     Brett

    "Set Up" = Same plug, prop, fuel, tank.

      OS.35S is essentially just as trouble free, in my experience. Use same hot plug, selection of 10-5/6 props to test, even the same fuel if the engine has some time on it and doesn't need break in. I ran OS.35S engines a lot in my early stunt days. Never had any issue and never broke one, except on a crash at the bottom of an outside loop of some kind. Airplane hit at about 30 degrees when something locked up the controls. I thought the engine had survived, but the angled impact distorted the case and the crank was no longer perpendicular to the cylinder. Not one crack or chip in the crank case, but it ruined the entire engine. I was able t o salvage the head, back plate and venturi parts. Crankshaft was actually OK. I used the parts on another engine I got in some dealings that was pretty toasted, and brought it back to life.  The OS.35S has the reputation for having soft rods, but I have never had any troubles.  For a Nobler, I think it's a better choice and just as trouble free as over powering it with a LA.46 would be. Save the .46 for a more appropriate airplane that could use the extra power. In a Nobler ARF or other typical .35 sized model, you are only using about half the potential of the .46, in my experience and opinion. The LA.40 is a better fit, I think.

   Type at you later,
    Dan McEntee
   

   

A question for Brett:

How are the LA 40 and the 46VF the "gold standard", better than the LA 40?

I meant to say: "better than the LA 46".

  You misread it, the 40VF and 46VF are much better than an 46LA, which is in turn better than a 40LA. This should be no surprise, the 40VF is one of the most successful stunt engines in history and dead-easy to set up and fly, the 46VF is a lot more powerful but not quite as plug-and-play, but still has an impressive record.


     Brett

Are the VF's all rear exhaust?

Thanks Brent.  That was informative and helpful.  Happy Thanksgiving!

There are few of them out there.  I checked.  Quite expensive and I usually fly profiles so I'm not sure I would venture out to buy one since they seem to be made for use with a tuned pipe.  I don't know if they run well with just a muffler.  I think I'll stick with these LA's.

I want to say that after I tried the LA 46 and the LA 25, that's about all I want to run, unless I go to a larger plane needing a larger engine.  I have been following these instructions for the use of stock 46's and 25's and having such a more enjoyable time.  Such easy starts.  Most of my 46's have 6mm venturi with the smaller NVA.

One question - can the piped VF's be used on profiles?

Allen,
If you want to try a pipe set up, both the LA .40 & .46 work well on smaller profiles.  No where near the power of a VF or as heavy, but they do work pretty well on smaller profile ships.

Just my opinion, both the 40 & 46 are good sport engines.  If you compared either of them to a VF, PA, or Jet engine you would be so surprised of the difference in power and use them as fishing sinkers, or something worse. 


Later,
Mikey