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# Speed calculations

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**1**of**1**## Speed calculations

I was talking with a pal at work about speed and line length since I knew he was good with math.

Basically we did some calculations to figure out the speed on 35' lines and used that figure to come up with the speed on 42' lines.

I can't remember the calculations at the moment, but I was wondering if it would be possible to run the calculations for the speed contest if someone had space limitations with 42'

Just wondering...

Ron

Basically we did some calculations to figure out the speed on 35' lines and used that figure to come up with the speed on 42' lines.

I can't remember the calculations at the moment, but I was wondering if it would be possible to run the calculations for the speed contest if someone had space limitations with 42'

Just wondering...

Ron

**Cribbs74****Moderator**

Posts : 11880

Join date : 2011-10-24

Age : 49

Location : Tuttle, OK

## Re: Speed calculations

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!

**GUS THE I.A.****Gold Member****Posts : 359**

Join date : 2012-08-15

Location : Wichita, Kansas

## Re: Speed calculations

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

Jim

Jim

**JPvelo****Diamond Member****Posts : 1963**

Join date : 2011-12-02

Age : 55

Location : Phoenix

Jim## Re: Speed calculations

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

Jim

**JPvelo****Diamond Member****Posts : 1963**

Join date : 2011-12-02

Age : 55

Location : Phoenix

## Re: Speed calculations

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

## Re: Speed calculations

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 was kind of just thinking out loud.

Ron

**Cribbs74****Moderator**

Posts : 11880

Join date : 2011-10-24

Age : 49

Location : Tuttle, OK

## Re: Speed calculations

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.

It is simple - for 35' lines if your plane is travelling at 60 mph then the lap time will be

Similarly - for 42' lines at 60 mph then the lap time will be

A lap time of 2 seconds on 35' lines will be

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

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!**ian1954****Diamond Member****Posts : 2688**

Join date : 2011-11-16

Age : 68

Location : England

## Re: Speed calculations

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.

Sounds too easy.

**JanPar**- Moderate Poster
- Posts : 12

Join date : 2013-07-08

Location : England

## Re: Speed calculations

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

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

**Cribbs74****Moderator**

Posts : 11880

Join date : 2011-10-24

Age : 49

Location : Tuttle, OK

**JPvelo****Diamond Member****Posts : 1963**

Join date : 2011-12-02

Age : 55

Location : Phoenix

## Re: Speed calculations

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.

**daddyo****Gold Member****Posts : 139**

Join date : 2012-11-26

Age : 55

Location : California

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