ORIGINAL: Airjunky
The first and biggest reason is one that's already been brought up, throttle response. I've seen a lot of 4-stroke profiles fly and every time the pilot is having to constantly work the throttle up and down to try and maintain a steady hover/torque roll, usually to no avail. It wears me out just WATCHING!
Show me any pilot hovering/TR down on the ground who is NOT working the throttle constantly. Heck man, that's one of the big things you have to learn. Just with a 4-stroke the response is quicker through the midrage (higher engine torque) and more audible.
There's just no way that an engine firing on every other revolution can ever have the throttle response of an engine that fires on every revolution. Add the extra weight and drag of the larger 4-stroke propeller and the spool up/down response time is much greater. What has better throttle response, your 2-stroke weedeater or your 4-stroke lawnmower?
Allright, Gator and I had a vertical drag raced at Cookeville. May OMP Edge/Saito 72 vs his EF Edge/Irvine53. Know what happened? I killed him out of the hole and jumped out in front, after the Irvine got wound up he caught me and pulled ahead at a higher speed. He has more HP, I have more mid/low torque, and a bigger heavier prop.
The other reason is weight. I've talked to many a 4-stroke enthusiast about this and the first thing they tell you is the Saito only weighs a couple ounces more. What they don't take into consideration is the weight of the whole power package and including the prop the package weighs several ounces more. Weight is critical......
From the Horizon site, Saito 72 with muffler, 16.6 ounces, From tower, OS 46FX with muffler 16.7 ounces.
Most people are used to 4 lb plus airplanes and have never flown a 3.5 lb airplane. Fly a 3.5 lb airplane with a 2-stroke engine for a few flights, then try and go back to that 4.5 lb 4-stroke lead balloon you've been flying. You'll put it up for sale so fast, your head'll spin.[&o]
........yeah, yeah.........your's flys great........I'm serious, fly a 3.5 lb plane and your opinion will change dramatically!
Rob
Ask Kenny and Mike B what they think of my 4lb+ OMP Edge 540/ 4-stroke after they flew it Sunday morning.
Both told me they were ready to order one on the spot.
Nothing wrong with 2-strokes, I've got several. They are cheaper, simpler and can power these planes perfectly well. But superior to 4-strokes? That's just an opinion and relative to flying style.
Hey, ask Swany. He was pretty put out with 4-strokes till he flew my birds. The Katana got good to him, torquin that Saito down low.