8 degrees does look like a lot, but first, it works and second, you lose very little forward thrust despite what you might think.

Do the math: Cos 8 = .99027. This means you are still getting over 99% of your forward thrust.

You don't notice it in the air. The first time you lose an engine and keep on doing acro and making turns both directions without rudder, you'll know what I mean.

I was flying my Twin-Air and doing a Cuban-8 about to roll upright on one of the down legs and an engine flamed out. As I rolled, the plane whipped off to one side. I immediately throttled to idle, leveled out and came up to half power. I put in the correct rudder and carefully landed. The Twin-Air has a big rudder, so there wasn't a problem holding it.

On the way hold with my flying buddy, Flaps Laffert, 83, also a former military pilot and long time modeler, we discussed single engine flying. I remembered reading somewhere back in the dim past, maybe 20-25 years ago that if you used 8-9 degrees out thrust, you wouldn't have any problems. We do a lot of experimenting, with himi building and me flying, so we decided to test it. We love a project.

I bought a Goldberg Tiger 2 ARF and he installed 2 nacelles for 2 OS .46AX engines I had. We put in 8 degrees out thrust. The plane came out heavy, 9.5 lbs, but flew OK. After trimming and feeling it out, we started the testing.

I fueled 1 tank full and the other one only got 11 of 33 cranks of fuel. After take off, I started doing acro without regard to the engines. It's one thing to throttle back and shut one down, but another to have it happen unexpectedly. The engine quit and the plane hardly even yawed. I flew some more and tried some acro-rolls in both directions and loops. Loops were hard due to the weight of the plane, but everything else was fine. I made a normal pattern and landed. The next flight I switched tanks to partial fill and it worked out the same.

At a later date, I changed engines to a Thunder Tiger .46Pro with a Tower tuned muffler and an 11-6 prop on one side and a plain bearing Thunder Tiger .42GP with stock muffler and a 10-6 prop on the other side. Out of sync, I would say. This combination flew fine. I could not tell I had mismatched engines.

After this testing, I am a big proponent of engine out thrust. My attitude now is not to worry about it. If one quits, so what, I have the other to get me home.

If any of you do any more testing to get concrete results, send them to me. I'll get them in print in my column. It's not how it looks, but how it flies that counts. (Engineer talking)