The thrust should be the same as the force delivered to the road from your tires when you are pedaling 30 mph.

You can get an idea of that several ways.

Get your max speed pedaling up a steep short hill. Measure the distance on the road and measure the vertical drop.

Divide the vertical drop by the distance you pedaled then multiply that by the weight of your bike + your weight.

This is the thrust you delivered at your maximum output.

Now check your maximum output on level ground. If you can go 30 mph for the same length of time as on the hill climb, you already have your answer.

If it is less than 30 mph you can still calculate the thrust necessary to go 30 with the propeller rule: power increases with velocity cubed.

For example, if you can only pedal 15 mph then the power required to go

30 mph is 8 times more than what you can generate.

Since power = thrust X velocity you can calculate your maximum horsepower by multipling you max thrust from the hill climb by your max speed on flat land.

Then correct for units by multiplying 5280 feet/mile and dividing 3600 seconds/hour.

Take this number and multiply it by the cube of (30/(your max speed)).

This is the power necessary to go 30.

Divide the power by speed (30mph X 1.47ft/sec/mph).

This is the thrust necessary to go 30mph.

For comparison Armstrong goes just about 28 at 0.8 hp or 440 ft'lb/sec.

Divide power by velocity to get thrust.

440/(28 X 1.47) = 10 lbs.

The reason you see very little jet engine propulsion of vehicles and boats is because air and gases are very light. The only way to get enough thrust is to:

- move a lot of air which requires a propeller which requires a shaft drive. If you have a drive you might as well run the wheels or a water prop.

or

- move the air fast which uses a lot of energy. Kinetic energy is

1/2 mv^2 and yet vehicle propulsion only increases with velocity. The vehicle moves forward slowly while the jet exhaust mostly gets wasted as heat in turbulent friction, stirring up air for no reason at all.

Newton once made a steam car using a boiler with a nozzle. Newton ignored his own equations and never calculated the thrust that would be necessary or what thrust would be possible with a little vapor.

It didn't work.

Bret Cahill

then multiply them by height in feet and divide by the time in seconds.

To get that you keen to know what force you are putting out