Force/Power optimization

Using derived above equations for current/thrust and current/voltage relation it is possible to tackle the main problem - how to improve thrust/power ration of a lifter to make it a more attractive flying device compared to conventional once. How would thrust/power ratio change if we adjust voltage, distance wire/collector, and wire radius? Results are shown below.

Used equations (see derivation above):

Thrust/current:

Current/voltage

Here:

And values of parameter used in calculation are:

1. Voltage optimization

Voltage was calculated for 100 points from minimal corona initiation voltage (6.9kV) calculated by Peek's equation for given distance, until voltage 100kV.

Note that spark discharge might occur before 100kV.

Here is resulting Thrust (in gram)/Power (in W) relation

..and Thrust/Voltage relation

As you could expect, thrust is increasing with voltage, however the efficiency (thrust/power) is decreasing rapidly from maximal 3 g/W to very small values.

2. Wire/collector distance optimization

Thrust is calculated by changing d from 30mm to 1m

Resulting Thrust/Power ration is shown below:

Exciting result is that thrust/power relation is increasing proportionally with distance and can reach huge values as 40 gm/W! However, absolute thrust is rapidly decreasing with distance as can be seen below:

Nevertheless, absolute thrust can be increased by increasing the length of wire/collector. Therefore increasing distance gives clear way of almost unrestricted efficiency increase.

3. Corona wire radius optimization

Radius was changed from gauge 50 (0.015 mm) to gauge 20 (1.5mm). Resulting thrust/power relation is given below:

It is great to see, that efficiency does not change, but thrust does! See below absolute thrust/radius dependence:

With decreasing radius thrust increases a lot, without losing efficiency!

Conclusion

l Increasing the wire/collector distance by simultaneous increase of wire/collector lenght can allow to achieve thrust/power ratios up to 40g/W.

l Decreasing wire radius increases thrust without degrading thrust/power ratio

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Experimental confirmations

Since the theory came out, experimental confirmations for this prediction have been obtained by several authors.

Particularly detailed investigation was undertaken by August R. Wohlt, who made exact measurement of power at different distances to collector. Note that from above equations and numerical results linear dependence of force/power efficiency on distance wire/collector follows. It can be made obvious by following:

As derived above equation of thrust is

F=i*d/k

and at the other hand, power is given as W=E*i

so thrust to power efficiency fw = F/W = i*d/k / (E*i) = d/(k*E)

Note that you dont need to know current to voltage relation to get this equation for efficiency!

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fw = d/(k*E)

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You can see here that efficiency is proportional to distance wire/collector and inversely proportional to voltage E. This a little surprising relation with voltage is observed because, despite the fact that force increases as E^2, the power consumption increases as E^3 so as result we have what we have - efficiency is inversely proportional to voltage....

    Now, August Wohlt has shown experimentally exactly this - efficiency is linearly changing with distance.

See http://www.serve.com/wohlt/lifters/pics/T-300-P30/efficiency.htm for striking experimental data!