WJETech (we push from the inside)

Tecnologías William Jhon Elliott Somerville E.I.R.L.

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Version 3 of the Fluid Space Drive (abbreviated).

Main page

 

 

The Fluid Space Drive V3 (FSD) is a method of propulsion in microgravity environments that has no need to expel propellant to generate thrust.

It does this by propelling a mass (M2) inside the FSD from one end of the spacecraft  to the opposite end but modifying the mass’s drag coefficient decreasing it’s velocity when traveling to the rear end of the spacecraft (M1)

 

What follows below is a step by step description of the method and the corresponding calculations (you can see a simple “tongue in cheek” description of the method here).

 

 

First the FSD’s dimensions (for this simulation):

 

 

Fig 1

 

Fig 1 shows a pressurized structure (M1) or spacecraft in a micro-gravity environment, inside the spacecraft is a 100k mass (M2) we call Ram Mass Assembly or RMA.

The RMA has freedom to move across the length (not breadth) of the spacecraft.

The pressurized structure (mass M1) is 30m long with a radius of 1,5 meters, the skin is 6mm aluminum (more or less Lunar Lander) (1), M1’s mass will be 808,02 k (2)

 

Fig 2

 

Fig 2 illustrates the RMA (M2), it has a series of flaps attached to servo motors, when the flaps are closed they form the shape of an open cylinder that functions as an air brake increasing the RMS’s drag coefficient therefore slowing it’s relative velocity inside the pressurized structure (M1).

 

Note: The illustration does not show the ideal aerodynamically shape for low drag, see note 3 for a better design

 

 

 

Recap

M1 (pressured structure) mass = 808.02 k

M2 (RMS) mass = 100 k.

 

Cycle 1 (forward ramming piston is activated)

Fig 3

The forward ramming piston is activated with a 400n force giving the RMA (M2) a push (F1) in the –X direction (Fig x) accelerating it in the –X direction (a2) with to 4 m/s (formula 1)

 

Formula 1

 

The opposite force (F2) gives the pressurized structure an acceleration in the +X direction (a1) of 0,495 m/s (formula 2).

 

 

Formula 2

 

Fig 4

As mass M1 is traveling unhindered (4) in the +X at 0.495 m/s (V1) it’s velocity will remain constant until another force is applied.

 

Mass M2 is traveling in a pressurized environment, the fluid (air) exerts a force (drag) as it encounters the air brake decreasing M2’s –X velocity.

 

The drag force can be calculated by using the drag equation (formula 1).

 

 

Fd = 0.5 * p * v² * A * Cd

 

Fd= drag force.

P= mass density of fluid (At 20 °C and 101.325 kPa, dry air has a density of 1.2041 kg/m3) in this example we will use 1.2 kg/m3 (x)

V= Velocity in m/s

A = surface of the 1m radius air brake (3.1415 m2)

Cd = drag coefficient for an open cone 2.2

Formula 3

 

Therefore using the above data we get:

 

Formula 4

 

The 66.350n force pushing in the +X direction will change M2’s velocity by 0.6635 (formula 5) resulting in a final velocity (for this time interval) of 3.3364 m/s (formula 6)

 

Formula 5

 

Formula 6

 

This calculation is to be repeated every time interval until M2 collides with M1’s inner rear hull with a final velocity of 1.4071398

 

 

 

 

 

A

B

C

D

E

F

1

time (s)

 Disp M1

 Disp M2

V M1

V M2

 Drag

2

1

          0.50

        4.00

0.495

3.336496

   66.350437

3

2

          0.99

         7.34

0.495

2.874854

   46.164159

4

3

          1.49

       10.21

0.495

2.532121

   34.273259

5

4

          1.98

       12.74

0.495

2.266237

   26.588441

6

5

          2.48

       15.01

0.495

2.053259

   21.297787

7

6

          2.97

       17.06

0.495

1.878431

   17.482815

8

7

          3.47

       18.94

0.495

1.732107

   14.632358

9

8

          3.96

       20.67

0.495

1.607692

   12.441521

10

9

          4.46

       22.28

0.495

1.500508

   10.718392

11

10

          4.95

       23.78

0.495

1.40714

     9.336855

12

11

          5.44 

      -25.19

0.495

1,325029

    8,211042

 

Column A = time interval (1 second)

Column B = total displacement of mass M1 at time interval.

Column C = total displacement of mass M2 at time interval.

Column D = Velocity of mass M1 at time interval.

Column E = Velocity of mass M2 at time interval.

Column F = Drag on M2 at time interval.

                     Drag change (M2)                                        Velocity change (M2)

Fig 5

For M1 (spaceship)

Elapsed time

11 s

Distance travelled

5.44 m

Fig 6

Recap

After the 400n force is exerted, the elements do the following:

M1 travels in the +X direction at 0.495 m/s constant velocity (formula 2).

M2 travels with an initial velocity of 4 m/s but is slowed by the drag generated by the air brake, it travels for 11 seconds until it collides with M1’s inner rear hull with a final velocity of 1.325 (Fig 5)

End of cycle 1

Cycle 2: M2 collides with M1’s rear (-X) inner hull.

Fig 7

The instant M2 contacts M1 an electromagnet (not shown) is activated to prevent any “bounce” insuring the collision is inelastic.

Therefore we have two masses (M1 and M2) that have an inelastic collision, to find the final velocity we use the formula:

Formula 7

 

Where M1 = mass of body 1

M2 = mass of body 2
V1 = Initial velocity of body 1
V2 = Initial velocity of body 2
v = Final velocity of both the bodies

The final velocity for inelastic collision is given by:

Formula 8

 

Formula 9

 

Therefore M1 and M2 are traveling in the +X direction at 0.294591 m/s after inelastic collision 1

For simplicity we permit masses M1 and M2 to travel together at 0.294591 m/s for 1 time interval (1 second), traveling at this time a distance of 5.7399 meters in 12 seconds the +X direction.

End of cycle 3

For M1 (spaceship)

Total elapsed time

12 s

Distance travelled

5.7399 m

Cycle 4: The rear ramming piston is activated with a 200n force.

Fig 8

 

The rear ramming piston is activated with a 200n force, this gives the RMS (M2) a push (F5) in the +X direction (Fig 8) accelerating it in the +X direction (a2) with to 2 m/s (formula 10)

Formula 10

 

As M2 was traveling with an initial velocity of 0.2945 m/s when the acceleration is added it has a final velocity of 2.2945 m/s

The opposite force (F6) gives the pressurized structure (M1) an acceleration (velocity change) of 0.24752 m/s in the -X direction (formula 11).

 

Formula 11

 

As M1 had an previous velocity of 0.294591 m/s (formula 9) it’s present velocity (formula 12) is 0.047075 (V1 + V2 = 0.294591 - 0.24752 = 0.047071)

 

 

 

Formula 12

 

As M2 travels inside M1 (fig 9) its velocity is decreased by drag, but because the air brake is deactivated (flaps in open position) its drag coefficient is only 0.3, M2 “catches up” to M1’s inner hull in time interval 29 (29 seconds from start of cycle) with a velocity of 1,6 m/s (M2 velocity of 1.7 – M1 velocity of 0.004)

 

 

A

B

 C

D

E

F

1

time

 Disp M1

Disp M2

V M2

Drag

v1

2

13

   0,04707501

2,047075015

2,023378204

2,369681

0,047075

3

14

   0,09415003

4,070453219

2,000226844

2,315136

0,047075

4

15

   0,14122504

6,070680063

1,977602246

2,26246

0,047075

5

16

   0,18830006

8,048282309

1,955486567

2,211568

0,047075

6

17

   0,23537507

10,00376888

1,933862765

2,16238

0,047075

7

18

   0,28245009

11,93763164

1,912714552

2,114821

0,047075

8

19

   0,32952510

13,85034619

1,892026352

2,06882

0,047075

9

20

   0,37660012

15,74237255

1,871783265

2,024309

0,047075

10

21

   0,42367513

17,61415581

1,851971029

1,981224

0,047075

11

22

   0,47075015

19,46612684

1,832575986

1,939504

0,047075

12

23

   0,51782516

21,29870283

1,81358505

1,899094

0,047075

13

24

   0,56490018

23,11228788

1,79498568

1,859937

0,047075

14

25

   0,61197519

24,90727356

1,776765849

1,821983

0,047075

15

26

   0,65905021

26,6840394

1,758914017

1,785183

0,047075

16

27

   0,70612522

28,44295342

1,741419112

1,749491

0,047075

17

28

   0,75320024

30,18437253

1,724270499

1,714861

0,047075

18

29

   0,80027525

31,90864303

1,707457966

1,681253

0,047075

 

Column A = time interval (1 second)

Column B = total displacement of mass M1 at time interval.

Column C = total displacement of mass M2 at time interval.

Column D = Velocity of mass M1 at time interval.

Column E = Velocity of mass M2 at time interval.

Column F = Drag on M2 at time interval.

                     Drag change (M2)                                        Velocity change (M2)

Fig 9

 

Fig 10

 

After 17 second of travel (29s from start of cycle fig 3) in the +X mass M2 “caches up” with mass M1 colliding with M1’s forward inner hull (Fig 11)

Fig 11

 

The instant M2 contacts M1 an electromagnet (not shown) is activated to prevent any “bounce” insuring the collision is inelastic.

Therefore we have two masses (M1 and M2) that have an inelastic collision, to find the final velocity we use formulas 13 and 14:

Formula 13

 

Where M1 = mass of body 1

M2 = mass of body 2
V1 = Initial velocity of body 1
V2 = Initial velocity of body 2
v = Final velocity of both the bodies

The final velocity for inelastic collision is given by:

Formula 14

 

Formula 15

 

 For simplicity we permit M1 and M2 to travel together for one time interval (1s), it will advance an additional 0.229931m

 

With this action in time interval 30 (seconds) M2 is in its original position (attached to M1’s forward inner hull) and the propulsion cycle is complete, therefore we have that M1 (the spaceship) has traveled a total of 6.75m in 30s.

 

 

Parameters at end of cycle For M1 (spaceship)

Total elapsed time

30 s

Distance travelled

6.77 m

 

With the above parameters we can calculate how much M1 (the spaceship) has accelerated using formula 16

 

Formula 16

 

The spacecraft has an acceleration of 0.015044m/s.

 

At first glance that does not seem like much, but as the spacecraft will be able to accelerate continuously as long as electrical power is applied it will soon become the fastest machine humanity has ever constructed.

 

Therefore, if we start with 0 velocity:

 

In one minute it will accelerate to 0.9 m/s

In one hour it will accelerate to 54 m/s

In one day it will accelerate to 1,296 m/s

In a week it will accelerate to 9,072 m/s (in two weeks it will surpass Voyager II’s present velocity of 15,400 m/s)

In one month it will accelerate to 38,880 m/s

In one year it will accelerate to 473,040 m/s

In one decade it will accelerate to 4,730,400 m/s

 

Notes (NOT COMPLETED YET)

 

 

Note 1: thickness and material of the pressured structures “skin” (

 

Note 2: Calculating M1’s mass

 

M1 length (h) = 30 m

M1 radius = 1.5 m

Thickness of aluminum skin = 0.6 mm = 0.0006 m

 

Volume of M1 = pi * r * r * h = 3.141592654 * 1.5 * 1.5 * 30 = 212.0575

 

 

Note 3 RMS design

 

 

 

Note x: Superior materials are available for the pressurized structures skin but the characteristics of aluminum are well known and adequate for this document.

 

 

 

Note 4:

 

Before we chant “Alpha Centauri here we come” conceder what percentage of the force excreted by the air drag on M2 is transmitted to the spaceship’s hull (nullifying the effect)

 

Let us include a factor pt (momentum transmitted) if pt=1 we will understand that all the force slowing M2 is transmitted to the spaceship’s hull, and if pt=0 no force is transmitted to the spacecraft.

 

The true pt value has to be determined by experimentation (just as the drag coefficient of various shapes is deduced by experiments), if pt has any value that is less than 1, then the method described in this document works as a practical method of propulsion in microgravity.

 

Assessment 1, decreasing M2 velocity by direct contact with the spacecraft (fig 7)

 

 

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Fig 7

 

If M2 is slowed by the friction created by direct contact with the spacecraft’s inner hull (fig 7), all the force (F4) that is slowing M2 will be transmitted (F5) to the spacecraft (M1) and regardless of M2’s final velocity we can assume the spaceship (M1) will not gain any acceleration (therefore the pt factor is 1)

 

Assessment 2, decreasing M2’s velocity by air brake when diameter of spaceship is almost identical to air brake’s diameter (tight fit) (fig 8).

 

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Fig 8

 

If the air brake’s diameter is a tight fit with the spacecraft’s diameter, it will act like a piston in a cylinder compressing the air in the –X side and come to a full stop before reaching the –X inner hull, but it is a logical assumption that the spacecraft will not gain acceleration in any direction.

 

Assessment 3, decreasing M2’s velocity by air brake when diameter of spaceship larger than the air brake’s diameter by a factor of X2 or more (fig 8).

 

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Fig 8

 

If we increase the spacecraft’s diameter with relation to the air brakes, there will be sufficient space for the air to flow around M2 without greatly affecting the spaceships velocity,  we can assume  that the pt factor is less than one, and if we continue increasing the spaceship’s diameter (fig 9) the pt factor will decrease.

 

 

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