Airplane weights

I think I've figured out why my Flite Streak is so much better than my Akromaster for relearning how to fly. Borrowed a good digital scale from work today, the Akromaster came in at 21 ounces with an Enya 19, and the Streak is 29 with a Stunt 35. The Streak is scratch built and to be fair, the Akromaster has had major repairs. Lots of extra glue and monokote on the Akromaster. Is 29 ounces a decent weight for a Flite Streak? Thanks

Is 29 ounces a decent weight for
>a Flite Streak? Thanks

The plane will fly quite well at that weight. Wing loading is around 10.5 ounces/sq ft. The 35 stunt should have no problem pulling it around. Line tension should be enough to let you know it's there and what's happening.

The one I learned to fly the complete pattern on weighed 28 ounces at birth with a Fox 35 stunt, before any of the subsequent flights/ crashes. At the end it still had no problem out flying me.

A general rule of thumb for both FF and CL is that the airplane should weigh (in ounces) close to the displacement (in hundredths of a cubic inch). I.E., 15 oz for a .15, 40 oz for a .40, etc. Adjust somewhat for anemic engines like the Fox .35!

Another useful thing I've found is that if you are running the engine on the ground, in the airplane, it should develop enough thrust to lift its own weight plus a bit more. If it will barely "hover" as you hold it vertical, you probably won't be too happy with it. You can skew the experiment by using a prop with less pitch than you would normally use for flying, of course. Steve

Steve Helmick
Renton, Washington
USA

Thanks, I hadn't heard that rule of thumb. Might explain why my 40 oz corroplast beast just staggers around with a 29? I think I'll keep it, though because it makes a pretty good basic trainer and is disposable. Steve, do you by chance work for Boeing?

I just can't figure why an analog scale should give a different answer.

An analog scale would be just fine, but the one I have access to is digital. You are right, of course, if both scales were accurate the reading should be the same.