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#500
by
Bob Woods
on 09 Sep, 2016 01:07
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A little strange that where you would expect the exhaust from the rear it's just blacked out and looks solid. Am I not seeing it?
https://www.youtube.com/watch?v=nG-TMhvZ1pU?t=63
I remember in WWII they stuck fake propellers on the new jets to hide the fact they were jets.
Just saying. It's probable that it could just be a black screen or something.
Shell
If you watch it closely, especially when the landing gear retract, it looks like CGI animation. I bet VAX could verify if that's the case.
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#501
by
SeeShells
on 09 Sep, 2016 01:42
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A little strange that where you would expect the exhaust from the rear it's just blacked out and looks solid. Am I not seeing it?
https://www.youtube.com/watch?v=nG-TMhvZ1pU?t=63
I remember in WWII they stuck fake propellers on the new jets to hide the fact they were jets.
Just saying. It's probable that it could just be a black screen or something.
Shell
Very unlikely, IMO. Taranis was always designed to fill the niche of low-observable, unmanned combat drone, with the same envisioned timeframes as the US' own programs, and aircraft systems integration is increasingly time consuming, especially in multinational endeavors. Packing in experimental propulsion technology that can barely be shown to work into a new combat air system that's already been in development for ten years would be an extra layer of complexity that would gravely endanger the whole program, and force them to find a new way to field any sort of drone based air combatant should the propulsion elements fail. With respect to the solid black bars, it looks like the video is censored. The exhaust system is something BAE's been particularly secretive about, presumably for classified infrared signature reduction features.
I can see where they would do CGI over the exhausts. Thanks.
Shell
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#502
by
tleach
on 09 Sep, 2016 01:44
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A little strange that where you would expect the exhaust from the rear it's just blacked out and looks solid. Am I not seeing it?
https://www.youtube.com/watch?v=nG-TMhvZ1pU?t=63
I remember in WWII they stuck fake propellers on the new jets to hide the fact they were jets.
Just saying. It's probable that it could just be a black screen or something.
Shell
I guess it could be. Even more telling than the blacked out "exhaust" vent is the fact that none of the actual, real, in flight images or videos of the Taranis seem to show the air inlet. Sure, you can find pictures of the inlet while it's sitting on the ground, but never video footage of the inlet while it's in the air. Maybe there is no inlet...
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#503
by
masterharper1082
on 09 Sep, 2016 02:35
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NASA tests: "For the EMdrive, the device that was tested here, thrust was consistently observed on the device to be between 30-and-50 microNewtons, giving us that 1.2 N/MW figure. But the limits of the measuring device’s threshold was just 10-to-15 microNewtons! In other words, these results may be consistent and interesting, but this isn’t as robust as anyone wants it to be." Source: http://www.forbes.com/sites/startswithabang/2016/09/02/nasas-impossible-space-engine-the-emdrive-passes-peer-review/#1be7fbba692c
The thrust obtain by NASA is consistent with the thermal balloon lift I have calculated in my previous post (38.33 micro N).
It is true, some people claim they debunked the hot air balloon theory but the thrust obtained by them is much higher than the one observed by NASA so likely they made some mistakes.
Balloon effect has no effect on the resonant cavity, because cavity can leak air
Worse. Now you have both air jet effect as well as hot air balloon effect.
Aren't thermal effects time delayed so you could separate those out? Shouldn't these forces persist for significant amount of time after switching the rf generator off?
Thermal effects can be separated out as will soon be shown.
Also using phase change wax, as Dave did, to store the thermal energy works very well, which allowed him to record a thrust of 18mN.
A phase change wax can work well for a short duration test to sort out physics, but once the phase change is completed, temperature will run away again. Eventually we will need something that can operate in a cycle, like a heat pipe or the frustum acting as an evaporator in a vapor compression cycle. A frustum could make a nice steam generator!
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#504
by
DrLOAC
on 09 Sep, 2016 03:58
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Just wanted to add a couple of things to this overview of solar array positioning.
There are several attitude options for a solar powered vehicle in LEO:
1) LVLH - Local Vertical Local Horizontal. Basically the vehicle flys like an airplane with the same side of the vehicle always facing Earth.
If you have an alpha gimbal it rotates around 4deg/min. Power is maximized (especially if a beta gimbal is also available) but drag increases when the arrays are face on to the velocity vector.
If the arrays are fixed facing vertical the vehicle recieves the most power at solar noon. Drag is reduced as the arrays remain edge on for the entire orbit. Power is reduced compared to alpha tracking, (beta angle losses can be mitigated if other constraints allow rolling the vehicle to reduce effective beta angle)
Arrays fixed facing directly into or away from the velocity vector significantly increase drag and reduce power below the other LVLH options but may be required due to other constraints, (comm, thermal, thruster, etc).
2)Solar Inertial. The vehicle attitude remains fixed in relation to the sun. This maximizes power even without gimbals at the expense of some drag as the vehicle rotates the array face into and out of the velocity vector.
3)Various Spin Attitudes - these are generally good for thermal issues as all sides of the vehicle spend time in the sun.
There are other attitudes but probably aren't applicable here. The ISS has flown many of these attitudes over the years but these days the only acceptable long term attiude is LVLH +XVV or -XVV
The array biasing schemes for the ISS are also a bit more complicated than just for drag reduction. Sometime you want to increase drag to lower altitude to be in place to rendezvous with another vehicle. We also bias to increase power at high beta angles where one array starts to shadow another.
The constraints this 6U cubesat EM drive test article will have to deal with will be partly influenced by the:
- direction of the EM drive thrust
- solar array gimbal capability of the satellite
- orbit to orbit power requirements across 6 months of beta angle changes
- comm requirements
- thermal constraints.
Among others.
Solar array pointing ca actually be a huge pain in the ass.
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#505
by
FattyLumpkin
on 09 Sep, 2016 04:43
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Re the drone...I always like to observe very carefully. I've never seen a structure like this which appears to be smack dab in the middle of the center of gravity. Notice the round structure in the middle. Comments folks? I don't have a clue. This reminds me of "Project Greenglow" Is this image seen in the video a true representation? Note the turbine extended (sticking out) of the back (not seen in vid) Hmmm...I don't think they'd be that flagrant about spilling the secret beans. Still...damned interesting!
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#506
by
Peter Lauwer
on 09 Sep, 2016 10:32
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Peter, the NASA frustum operated best (force/watt) at TE012 (I don't believe TE013 was ever modeled or tried for). The sim of TE012 works well but with the antenna(s) in a different position.
NASA had difficulty operating their frustum in TE012 with the antenna in the original position on the side...(couldn't get more than 2.6 Watts into it at 1.8804 GHz + other modes close by).
If you want to keep everything the same in the NASA frustum TM212 is the way to go, but the Q is not nearly as high as with TE012. X_Ray just recently (a few pages back) showed some sims as to why TM 212 was much easier to stimulate than TE012. I'll go back and try to locate the specific page(s).
Attached is the NASA frustum 1st in TE012 and 2nd in TM212 (marked TM211) FL
Thanks a lot, FL. I certainly want to try out several modes, certainly the TM212 and TE012.
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#507
by
Rodal
on 09 Sep, 2016 11:45
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The Taranis powerplant is well known: a Rolls-Royce Turbomeca Adour Mk951 dual flow, moderate by-pass ratio turbofan jet engine. It is a collaborative engine between Rolls-Royce of the UK and Turbomeca (SAFRAN S.A.) of France,
with a thrust range from 28.9 kN (6,570 lbf) dry to 37.4 kN (8,500lbf) with reheat. (
http://www.safran-helicopter-engines.com/engine-partnerships/partnerships/adour/adour )
Compare these thrust ranges (over 30,000 Newtons) with what has been claimed for the EM Drive:
NASA: less than 100 microNewtons, Shawyer: less than 175 milliNewtons.
Several orders of magnitude less !
That is 300 million times less for NASA and 170,000 times less for Shawyer's claims.
The improvements in the Adour 951 engine include the use of optimised materials in the hot section for higher durability, a new fan design to provide higher thrust and digital rather than hydrodynamic control. Full authority digital engine control (FADEC) will provide engine surge protection, and automated control and recovery. It has a target maintenance interval of 4,000 hours.
Adour was originally
developed primarily to power the Anglo-French SEPECAT Jaguar fighter-bomber, achieving its first successful test run in 1968,
practically 50 years ago !More than 3,000 Rolls-Royce Adours have been produced, for over 20 different armed forces with total flying hours reaching 8 million in December 2009.
Pictures of the exhaust while flying:
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#508
by
bad_astra
on 09 Sep, 2016 15:48
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Has anyone tried suspending one of these emdrive test articles in a fluid medium? I would be interested to know whether there is any chance that the thrust-section of the frustrum causes any sort of cavitation.
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#509
by
johnatan warp drive
on 09 Sep, 2016 18:58
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Re the drone...I always like to observe very carefully. I've never seen a structure like this which appears to be smack dab in the middle of the center of gravity. Notice the round structure in the middle. Comments folks? I don't have a clue. This reminds me of "Project Greenglow" Is this image seen in the video a true representation? Note the turbine extended (sticking out) of the back (not seen in vid) Hmmm...I don't think they'd be that flagrant about spilling the secret beans. Still...damned interesting!
This resembles the inlet of the turbine.
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#510
by
Fan Boi
on 09 Sep, 2016 20:10
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Here is another possible way to measure "thrust" using two of these devices: Bolt two of them together facing each other but with a "squeeze-ometer" in between. Power on both and see if there is any squeezing going on. I understand there are squeeze meters that can measure the Casimir affect so they must be super sensitive. Doing that would also allow you to orient the assembly in any orientation you want and the squeeze should remain.
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#511
by
Carl G
on 09 Sep, 2016 23:06
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Thread cleaned of nonsense.
1) Do not insult other members. If they are talking nonsense, provide your reasoning. If could be 2,000 words long, but if it includes "you're an idiot" you're losing your post. Forum rules.
2) Don't multiquote to crazy levels. It makes people go blind when reading.
3) If you're only here to say "It doesn't work", you're trolling. You may be right, but posting it 10 times doesn't make you win an argument.
4) Turn off your "sent via tapatalk via my iphone" setting if using tapatalk. It's annoying.
These threads have been very civil over recent months, so the alerts today to nonsense means we stop it immediately and that's why we did today, to the benefit of those providing interesting posts.
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#512
by
dustinthewind
on 09 Sep, 2016 23:50
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Here is a thought. Let's measure the power in through the antenna. Doing so we should know the amount of heat that should be present in the frustum. Immerse the thing in a substance that has heat capacity and run it over a period of time. Later we measure the temperature and we get the time accumulated energy dumped into heat.
If there is any work being done on something that is escaping the frustum, then some of that energy will be lost and not show up as heat. We would have some discrepancy in the energy put in and the heat generated? Bad or good idea?
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#513
by
cee
on 10 Sep, 2016 00:48
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A little strange that where you would expect the exhaust from the rear it's just blacked out and looks solid. Am I not seeing it?
https://www.youtube.com/watch?v=nG-TMhvZ1pU?t=63
I remember in WWII they stuck fake propellers on the new jets to hide the fact they were jets.
Just saying. It's probable that it could just be a black screen or something.
Shell
I guess it could be. Even more telling than the blacked out "exhaust" vent is the fact that none of the actual, real, in flight images or videos of the Taranis seem to show the air inlet. Sure, you can find pictures of the inlet while it's sitting on the ground, but never video footage of the inlet while it's in the air. Maybe there is no inlet...
Looks alot like the Northrup XB47B
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#514
by
MaxIsp
on 10 Sep, 2016 01:24
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A little strange that where you would expect the exhaust from the rear it's just blacked out and looks solid. Am I not seeing it?
https://www.youtube.com/watch?v=nG-TMhvZ1pU?t=63
I remember in WWII they stuck fake propellers on the new jets to hide the fact they were jets.
Just saying. It's probable that it could just be a black screen or something.
Shell
I guess it could be. Even more telling than the blacked out "exhaust" vent is the fact that none of the actual, real, in flight images or videos of the Taranis seem to show the air inlet. Sure, you can find pictures of the inlet while it's sitting on the ground, but never video footage of the inlet while it's in the air. Maybe there is no inlet...
Well there better be some place for the air to go in and the exhaust from the Pratt & Whitney F100 engine to exit. It is well documented that this is the actual engine in use on this vehicle.
I think what you are seeing or "not seeing" is the fact the the inlet is "serpentine" with a twisting air path to the jet engine compressor. There is a ramp that goes upward just past the inlet lip. That ramp makes it look like the inlet is closed up. Past that I would suspect the back side of the ramp drops to the compressor face of the engine and changes to a round shape. The exhaust is also diverted from the round exhaust off the end of the jet engine to a flatter and wider slot. It is all about stealth - hiding hot and metallic surfaces from thermal imaging and radar.
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#515
by
MaxIsp
on 10 Sep, 2016 01:28
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Well I did not back track enough to see we were talking Taranis not X-47.
I believe the Taranis is basically the same design with respect to stealth features. And Uses an existing engine as Dr. Rodal pointed out below.
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#516
by
Prunesquallor
on 10 Sep, 2016 01:51
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NASA tests: "For the EMdrive, the device that was tested here, thrust was consistently observed on the device to be between 30-and-50 microNewtons, giving us that 1.2 N/MW figure. But the limits of the measuring device’s threshold was just 10-to-15 microNewtons! In other words, these results may be consistent and interesting, but this isn’t as robust as anyone wants it to be." Source: http://www.forbes.com/sites/startswithabang/2016/09/02/nasas-impossible-space-engine-the-emdrive-passes-peer-review/#1be7fbba692c
The thrust obtain by NASA is consistent with the thermal balloon lift I have calculated in my previous post (38.33 micro N).
It is true, some people claim they debunked the hot air balloon theory but the thrust obtained by them is much higher than the one observed by NASA so likely they made some mistakes.
Would suggest you ignore that data, as from what I'm told it is not even close to the paper's results as the thrust is reported to be much higher and uncertainty is much lower.
In this, TT is correct.
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#517
by
tleach
on 10 Sep, 2016 02:56
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#518
by
MaxIsp
on 10 Sep, 2016 03:04
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I think what you are seeing or "not seeing" is the fact the the inlet is "serpentine" with a twisting air path to the jet engine compressor. There is a ramp that goes upward just past the inlet lip. That ramp makes it look like the inlet is closed up. Past that I would suspect the back side of the ramp drops to the compressor face of the engine and changes to a round shape. The exhaust is also diverted from the round exhaust off the end of the jet engine to a flatter and wider slot. It is all about stealth - hiding hot and metallic surfaces from thermal imaging and radar.
Time to let it go, MaxIsp, I was just joking around. I guess I should have used more smiley faces to better communicate that fact...
Besides, everybody knows that the military's real EM Drive testbed is actually the X-37B. They've performing extensive in orbit EM Drive testing under the cover of testing a Hall Effect thruster since 2015. 
I think my visual filter on smiley faces was turned on or my eyesight is just getting worse. Those are just fuzzy yellow dots....
Right?
Thanks.
Back to EMdrive design, building, testing.
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#519
by
TheTraveller
on 10 Sep, 2016 12:51
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In this, TT is correct.
I'm told the EW paper is in circulation.
Highly doubt AIAA will be the 1st to do a public release of the paper.
Then there is what happened after the 2015 in vac test program was completed and what happened after that next test program was completed.
