4 stroke gas engines have not caught on yet. There have been a few around like the Honda and the Ryobi but they were not powerful and light enough for anything but just flying around. They had close to 2 cubic inches displacement.

Also there have been a very few glow four stroke engines converted over the spark ignition and gas but it's not very common.

When you get above 2 cubic inch displacement, the cost of glow fuel begins to really enter into the picture. Also the larger 2 cycle glow engines like the big Super Tiger 3200 and 4500 usually have to use a different glow fuel than what you would use in your .46 engine.

Four stroke glow engines have been around for close to 30 years but only in the recent years, have they been refined enough to be used in fun fly. It took a lot of refineement to get to where we are today.

The more powerful gas engines used in the TOC planes cost more than a $1000 each. They have been very refined over the years.

Perhaps, in the future with a refinement of materials like in NANO technology, a TOC plane will have a four stroke gas engine?

Enjoy,

Jim