Hi Ray,
As I said, I'm not quite ready for a full review yet, but I'll share what I've found thus far.

From the outside, the case mounting is identical to the nitro 40 (as in the 46) so it is a simple bolt in affair as far as mounting goes. They did not feel the need to make the case any larger for the gas, and I can agree with them on this point as the 40 case is quite robust as is. NV tends to build a strong, lightweight case by using high grade materials and good design, rather than use a big, clunky casting. Unfourtunatley I have "tested" this on a few occassions as I tend to push the envelope with my flying so I never get those nice crashes where you bend the landing gear and break a prop. Mine tend to look more like the old Wide World of Sports "The Agony of Defeat" newsreels Even when I have to do a bit of digging on the field to get the nose of the plane out I have yet to break one of their cases, enough said.

From there, things start to change. The head button is different in a number of ways. First off it takes a different glow plug, not a standard glow or 4-stroke. It is also a bottom sealing plug, like the Nelson plugs we use on the .061 and Cox motors, but a different configuration and they will not interchange. The button itself is also a different design and made just for this motor. If you had any of the early NV 40's you might remember they also included three set screws to do the final locking of the head button. They discontinued them after a while, but they are back for this motor, perhaps due to the increased power or the differences in the way the fuel burns.

Moving on to the carburator it becomes apparent that this motor was "designed" for gasoline, not just adapted like a disel conversion. The carburator is larger in many ways. The bore is larger, which may explain some of the increased power but I suspect it has more to do with proper atomization of the fuel. Both the high speed and low speed needles are also larger and made for the motor as is the NVA tubes. The design seems to be well thought out and tested as it pulls the heavier fuel without the need for a pump or butterfly carb.

Another welcome change is the option of a "straight out" muffler in addition to the standard "tilt down" version of the 40 Nitro. This makes fitment in a cowl much easier and gives more mounting options.

In opperation, like all gasoline motors, you need to get it wet to start as gasoline ignites much differently than glow fuel. Since there is no pump or choke, you prime it just like a standard glow motor. I have found that because gas motors need to warm up a bit, without a choke or butterfly, it works best to richen the needle 1/4 turn or so when stating cold. I tend to do this as a standard practice on cold starts on all my motors anyway as the majority of early engine failures I see at the field are due to lean runs. Once running, the standard practice of setting it 300 to 500 rpm off of peak holds especially true on this motor as you are pulling thicker fuel without a pump. This will yield a nice flight with no tendacies to lean out at the top of a vertical "8", great idle, and smooth, dependable power transitions.

Speaking of needle settings, I have yet to adjust the low speed needle, or have the need to. This does not surprise me as NV has made a practice of designing their carbs and ramps to meter fuel at a very precise level. To this end their 15 and 25 motors are available with a 2 needle carb or a single needle without even an air bleed adjustment. I have some of each and find little difference in actual use. My .074 idles like a swiss watch and has no airbleed or low speed needle. But I am happy to have the low speed needle there, just as I like having extra switches on my radio. Not that I uses them all, but you never know

I have not done any actual measuring of ports between the nitro and gas motors, so I can't comment on changes there. The motor definatley makes more torque than the nitro version, as it will swing a bigger prop at the same rpm. This may be due to the gas burning a bit slower than the nitro and giving it a longer "push" on the piston, much like using a slow burning powder in a rifle. This issue is best left to the engineers to debate. Also to note, like the rest of their motors, the gas motor also keeps running stronger and smoother the more flights I put on it. The only low speed adjustments I have made are to keep lowering the idle as it gets more time on it. It has yet to flame out or quit on idle, even after a few bumpy landings on windy days and always throttles up nicely on touch and go's.

Please ask if I have left anything important out so far,
Bill