Fun to play around with:http://amrita.vlab.co.in/?sub=1&brch=280&sim=1518&cnt=4
The pendulum arm pivots about two linear flexure bearings in a plane normal to gravitational acceleration. The flexure bearings provide an essentially-frictionless and hysteresis-free interface between the static test stand fixed structure and the dynamic pendulum arm. Test article force is measured by measuring the pendulum arm displacement and calculating the force via the flexure bearing spring constants that were determined during test facility setup
Quote from: Mulletron on 11/10/2014 11:50 pmFun to play around with:http://amrita.vlab.co.in/?sub=1&brch=280&sim=1518&cnt=4QuoteNothing is suspended from a wire:
Nothing is suspended from a wire:
Quote from: Mulletron on 11/10/2014 11:50 pmFun to play around with:http://amrita.vlab.co.in/?sub=1&brch=280&sim=1518&cnt=4Nothing is suspended from a wire:Quote from: Brady, March, White, et.al.The pendulum arm pivots about two linear flexure bearings in a plane normal to gravitational acceleration. The flexure bearings provide an essentially-frictionless and hysteresis-free interface between the static test stand fixed structure and the dynamic pendulum arm. Test article force is measured by measuring the pendulum arm displacement and calculating the force via the flexure bearing spring constants that were determined during test facility setup NASA Eagleworks has an inverted pendulum.According to Paul March, NASA Eagleworks uses as a torsional spring two Riverhawk C-flex bearing blocks with torsional spring constant (http://flexpivots.com/cantilevered-single-ended-pivot-bearings/) centered 2.38" above and below the centerline of the 24.00" long by 1.50" Faztek aluminum pendulum arm. The long end of the pendulum arm is 15.5" from the torque pendulum's center of rotation, which makes the other short-end of the pendulum arm 8.5" from the center of rotation. However, the NASA report shows a linear flexure bearing http://flexpivots.com/linear-flexure-bearing/
Quote from: Rodal on 11/11/2014 12:00 amQuote from: Mulletron on 11/10/2014 11:50 pmFun to play around with:http://amrita.vlab.co.in/?sub=1&brch=280&sim=1518&cnt=4Nothing is suspended from a wire:Quote from: Brady, March, White, et.al.The pendulum arm pivots about two linear flexure bearings in a plane normal to gravitational acceleration. The flexure bearings provide an essentially-frictionless and hysteresis-free interface between the static test stand fixed structure and the dynamic pendulum arm. Test article force is measured by measuring the pendulum arm displacement and calculating the force via the flexure bearing spring constants that were determined during test facility setup NASA Eagleworks has an inverted pendulum.According to Paul March, NASA Eagleworks uses as a torsional spring two Riverhawk C-flex bearing blocks with torsional spring constant (http://flexpivots.com/cantilevered-single-ended-pivot-bearings/) centered 2.38" above and below the centerline of the 24.00" long by 1.50" Faztek aluminum pendulum arm. The long end of the pendulum arm is 15.5" from the torque pendulum's center of rotation, which makes the other short-end of the pendulum arm 8.5" from the center of rotation. However, the NASA report shows a linear flexure bearing http://flexpivots.com/linear-flexure-bearing/Well, the pic shows the bearing block anyway, not necc the c-flecs (always used c-flex me self back then)
1) The dynamic response of this structure (the EM Drive on the torsional pendulum) is governed by the ratio of the excitation frequency to the natural frequencies of the structure. 2) Mulletron stated that he didn't care about the natural frequency of the pendulum... 3) Mulletron was under the completely wrong understanding that the pendulum at NASA Eagleworks was a hanging pendulum...4) blah blah blah......what is unknown is the lumped mass (the EM Drive) at a given distance from the center of rotation.5) Moreover, we don't need to know the mass to compute the dynamic response at all. ... [per] [Rodal], March, Frob, NotSo...
Hope this mention [of] prosecution will not [cause to be entertained] a certain level of paranoia : fact is, like for any rational investigation activity, hair splitting is also part of the job of science.
I propose the hypothesis that the microwave amplifier is the cause of the lack of punch of the signal, if the amplifier takes more than .1s to reach full power.
....Quote from: Rodal5) Moreover, we don't need to know the mass to compute the dynamic response at all. ... [per] [Rodal], March, Frob, NotSo... ....5) Which primitive man flat out do not get, and which p.m. look at with very wary eye. (Vewwy wawwy, per Elmer Fudd)
5) Moreover, we don't need to know the mass to compute the dynamic response at all. ... [per] [Rodal], March, Frob, NotSo...
@Rodal - Did you write that the side walls of the cone are not subject to heating? Because if the side walls did warm the outside boundary layer of air then the warmer boundary layer would rise causing a reduced pressure over the outside of the cone walls. The result would be a net force toward the small end. Actually, I just glanced at the ideal gas law relationship and no easy way to calculate the lift force on the cone walls popped out. Its a constant pressure set-up because pressure is atmospheric, but total pressure includes dynamic pressure of the rising boundary layer. And of course the aerodynamic force is generated by the difference in static pressures caused by dynamic pressures. In this case with very low heating (small temperature change) the dynamic pressure would be very small. But then the cone walls are quite large so a very small pressure difference might create a small measured thrust.Say 1/4 of the cone on each side contributed to aerodynamic normal force. The total area normal dot axial direction is big end area minus small end area divided by two (2*1/4). That is, about 193 cm2. Since F = P*A, to develop 50 micro N needs 0.00259067 N/m2 or 2.6 milli-Pa. Dynamic pressure = rho*V2/2 and rho at sea level is about 1.225 kg/m3. It boils down to requiring a rising air velocity greater than V ~ 6.5 cm/s which is probably to much to be generated quickly enough to avoid a tell-tale time lag in the measured signal.It was just a thought. This idea doesn't even consider the Cannae superconducting thruster, to which it could not apply.
The test campaigns are discussed in the video too.@39:25 the slide says the conical frustum has a 4" dielectric resonator!?!?!
....What's up with the disparity between the 4" dielectric slug from the slides and the reported 6.25"x1.06" slugs from the paper? Much inconsistency with this one....
I'm wondering if someone screwed up while drafting the paper and those 6.25"x1.06" dielectrics are actually what is in Cannae. A tall narrow cylinder.If the dielectric in the conical frustum is 4" (Tall or wide or both? What is supporting it?), we have our cavity estimates way off.I'm not willing to bother anyone by emailing them for clarification. Anyone else already have a dialogue going?