Speed calculations

It seems as though  35' lines would be an unfair advantage because of the reduced drag.

Jim

GUS THE I.A. wrote:Last autumn, I painted new 42' marks on the circle, to aid in setting line length. We were getting hot and heavy into Mouse stuff, before it turned really cold. We were really zipping around the circle, though. Any shorter lines, and you might get screwed into the ground! The 42' length makes them pretty fast, already. Lines of 35 feet - good luck!

Ditto that, I've had my planes out a couple times just playing around and I was spinning pretty good with 42' lines.

Jim

Ron.. just make sure you wear flat-sole shoes... or better yet... use a swivel office chair!!   

Ok, I was just thinking about those who may have space considerations. 35' can be done, it's been done before.

I was kind of just thinking out loud.

Ron

I did a bit of maths on this topic and looked for a way to simplify the calculation but wasn't sure about the definition of 35' and 42' lines.

I assumed that the plane will either fly in a circle of either 70' or 84' diameter.

Anyway I ended up with two simple numbers to use in calculation of speed or lap time.

150 for 35' and 180 for 42'.

It is simple - for 35' lines if your plane is travelling at 60 mph then the lap time will be 150/60 or 2.5 seconds.

Similarly - for 42' lines at 60 mph then the lap time will be 180/60 or 3.0 seconds.

A lap time of 2 seconds on 35' lines will be 150/2 or 75 mph. For 42' lines it will be 180/2 or 90 mph.


Very simple - check the sums for a 42' line and a 4 second lap.

((84 * 22/7)/4) = distance travelled in 1 second = 66 ft

Distance travelled in 1 hour = 66 * 60 * 60 = 237,600 ft

237,600 ft = 237,600/5280 miles = 45 mph

A lot of maths when all you had to do was 180/4 = 45mph!

That is a simple way of looking at this. So if a plane is going to do 100 mph on 35 ft lines then each lap would be 150/100 seconds. 1.5 seconds but would increase to 180/100  or 1.8 seconds on 42 ft lines. 0.3 seconds difference.

Sounds too easy.

Thanks for the info guys. Like I said I was looking to see if there was a way of calculating speed based on line lengths.

So theoretically we could determine overall speed regardless of line length.

I am ok with the standard 42'

I was more concerned if someone didn't have enough room and had to go shorter, but still wanted to compete.

Ron

http://www.flycl.co.uk/control_line_speed_calculator.htm

There's no way you can get this exactly right because of line drag, and drag goes up very quickly with speed, but maybe you can get sorta close.