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#900 by TheTraveller on 18 Aug, 2017 18:02
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Pluto orbit mission profile, with mid way flip and burn at 2,300mkm & Pluto orbit.
Using non cryo 2009 SPR Flight Thruster, 20kW Rf and 3,000kg spacecraft.
Other configurationscare doable.
Max KE J < Rf input J, so no OU.
Fine, but I'm sure you're not now saying the Mars Missions you posted yesterday are not possible. If it works for this one it works for the others. But the other have higher KE in the starting frame than total input Rf. That's OU according to the simple, straightforward definition discussed here. Again, I'm not saying it's impossible but I just want to know how you rationalize that? And what does Mr. Shawyer say? Please don't just ignore this question. Thanks.
Bob,
Build a model with 0.99 sec of acceleration and 0.01 sec of no acceleration, with no carry forward of the last 0.99 sec burn's V and KE gain.
Ie accelerate for 1,000 x 0.99 sec burns, isolated by 0.01 sec of no acceleration. KE Joule gain at the end of each 0.99 sec burn is less than the Rf input Joules during the burn.
BTW both Roger and myself use pulsed Rf input.
I understand that and I agree you conserve energy wrt to the instantaneous rest frame during each cycle. As I said yesterday, that was prof. Woodward's previous position and it makes sense but you are still not addressing the question at hand which remains, you put in far less total Rf, no matter how you do it, than you get KE out wrt the starting frame, which is what I call the naive view of energy conservation. How do you answer that? It's ok to say its a red herring or that it doesn't matter but please, say something about it. Thanks.
Hi Bob,
The EmDrive obeys a = f / m.
Constant acceleration causes a constant V increase and constant internal Doppler shift, which drives force generation. Until EmDrive V gets to be a significant fraction of c, the force generated is constant. Once EmDrive V becomes a significant % of c, internal Doppler shift reduces and thrust reduces. All covered in Roger's 2014 peer reviewed paper.
So yes EmDrive V increase can cause a reduction in thrust, but not because of assumed KE gain. -
#901 by Bob012345 on 18 Aug, 2017 18:17
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Pluto orbit mission profile, with mid way flip and burn at 2,300mkm & Pluto orbit.
Using non cryo 2009 SPR Flight Thruster, 20kW Rf and 3,000kg spacecraft.
Other configurationscare doable.
Max KE J < Rf input J, so no OU.
Fine, but I'm sure you're not now saying the Mars Missions you posted yesterday are not possible. If it works for this one it works for the others. But the other have higher KE in the starting frame than total input Rf. That's OU according to the simple, straightforward definition discussed here. Again, I'm not saying it's impossible but I just want to know how you rationalize that? And what does Mr. Shawyer say? Please don't just ignore this question. Thanks.
Bob,
Build a model with 0.99 sec of acceleration and 0.01 sec of no acceleration, with no carry forward of the last 0.99 sec burn's V and KE gain.
Ie accelerate for 1,000 x 0.99 sec burns, isolated by 0.01 sec of no acceleration. KE Joule gain at the end of each 0.99 sec burn is less than the Rf input Joules during the burn.
BTW both Roger and myself use pulsed Rf input.
I understand that and I agree you conserve energy wrt to the instantaneous rest frame during each cycle. As I said yesterday, that was prof. Woodward's previous position and it makes sense but you are still not addressing the question at hand which remains, you put in far less total Rf, no matter how you do it, than you get KE out wrt the starting frame, which is what I call the naive view of energy conservation. How do you answer that? It's ok to say its a red herring or that it doesn't matter but please, say something about it. Thanks.
Hi Bob,
The EmDrive obeys a = f / m.
Constant acceleration causes a constant V increase and constant internal Doppler shift, which drives force generation. Until EmDrive V gets to be a significant fraction of c, the force generated is constant. Once EmDrive V becomes a significant % of c, internal Doppler shift reduces and thrust reduces. All covered in Roger's 2014 peer reviewed paper.
So yes EmDrive V increase can cause a reduction in thrust, but not because of assumed KE gain.
My question was not covered in the 2014 paper. I really don't mean to be rude but it's so simple yet you either fail to grasp it (which I doubt) or just don't want to address it.
Also, I'm not convinced by the Doppler arguments. It doesn't mater how fast the drive is going in reference to some other frame. In its own frame there wouldn't be any significant shift of light going from one end to the other or you would have an absolute reference frame. Relativistically, a constant acceleration in the ships instantaneous rest frame is reduced by gamma cubed in the starting frame at relative velocity v. -
#902 by TheTraveller on 18 Aug, 2017 18:51
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My question was not covered in the 2014 paper. It's so simple yet you either fail to grasp it or just don't want to address it.
Hi Bob,
The EmDrive's starting frame relative V and KE has no effect on thrust in the frame of the EmDrive.
Any V and KE calc is just that a calc based on the V reference frame at acceleration start.
The attachment, from Roger's peer reviewed paoer, should make it clear that V & KE increase have no effect on constant acceleration, constant velocity increase relative to starting velocity frame and related increasing KE, also in reference to the starting velocity frame.
This will upset a few folks, so I created a Pluto orbit mission profile that shows starting velocity reference frame to max mission velocity can be done without the need to apparently go OU and ignore KE gain relative to the starting V frame.
So roll it either way.
Do mission profiles that show KE < Rf energy input or
Do more aggressive mission profiles that don't care about KE gain relative to the starting V frame.
Either way no one can ever again claim the EmDrive breaks CofE as mission profiles can be constructed where it does not break CofE.
In regard to the acceleration, constant velocity change, internal to the cavity Doppler shifts, Roger explained this in his 2013 IAC paper as attached.
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#903 by Bob012345 on 18 Aug, 2017 18:58
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My question was not covered in the 2014 paper. It's so simple yet you either fail to grasp it or just don't want to address it.
Hi Bob,
The EmDrive's starting frame relative V and KE has no effect on thrust in the frame of the EmDrive.
Any V and KE calc is just that a calc based on the V reference frame at acceleration start.
The attachment, from Roger's peer reviewed paoer, should make it clear that V & KE increase have no effect on constant acceleration, constant velocity increase relative to starting velocity frame and related increasing KE, also in reference to the starting velocity frame.
This will upset a few folks, so I created a Pluto orbit mission profile that shows starting velocity reference frame to max mission velocity can be done without the need to apparently go OU and ignore KE gain relative to the starting V frame.
So roll it either way.
Do mission profiles that show KE < Rf energy input or
Do more aggressive mission profiles that don't care about KE gain relative to the starting V frame.
Either way no one can ever again claim the EmDrive breaks CofE as mission profiles can be constructed where it does not break CofE.
Ok, I'm going to assume your position is that it's a red herring and that the apparent OU doesn't really need a explanation as long as input Rf is greater than the rate of kinetic energy gain in the immediate, local instantaneous rest frame of the device. I can accept that position well enough but I just wish it would be clearly acknowledged by those that hold it. Thanks.
p.s. The peer reviewers should have made Mr. Shawyer address that point in the paper in my opinion. -
#904 by TheTraveller on 18 Aug, 2017 19:09
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p.s. The peer reviewers should have made Mr. Shawyer address that point in the paper in my opinion.
Hi Bob,
From memory, the peer review process took around 18 months. I would assume Roger did address the KE issue with the reviewers. -
#905 by meberbs on 18 Aug, 2017 19:29
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Ok, I'm going to assume your position is that it's a red herring and that the apparent OU doesn't really need a explanation as long as input Rf is greater than the rate of kinetic energy gain in the immediate, local instantaneous rest frame of the device. I can accept that position well enough but I just wish it would be clearly acknowledged by those that hold it. Thanks.
That position doesn't really make sense, because it is a known fact that accelerating reference frames can't have conservation of energy directly applied to them. (There are way to do it, but aren't worth the effort.)
It does not matter anyway, because no matter what happens in the device frame, it does not change the fact that it is trivial to turn such a device into a power generator by having it accelerate and then extracting the kinetic energy.
There are ways to explain this from the device taking energy from somewhere or something else, or even that energy conservation simply does not hold. Before considering the implications of any of these, the fact of using the device to generated energy must be accepted. Talking about energy conservation in the instantaneous rest frame is simply a way to ignore the issue.
I will not bother responding to TT directly, since TT has not addressed the simple fact that his last spreadsheet he shared did not even have the proper units in the energy calculation. The Pluto spreadsheet he has since shared a screenshoot of seems to have been further changed presumably to remove any remaining resemblance to the laws of physics. -
#906 by TheTraveller on 18 Aug, 2017 20:14
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Ok, I'm going to assume your position is that it's a red herring and that the apparent OU doesn't really need a explanation as long as input Rf is greater than the rate of kinetic energy gain in the immediate, local instantaneous rest frame of the device. I can accept that position well enough but I just wish it would be clearly acknowledged by those that hold it. Thanks.
That position doesn't really make sense, because it is a known fact that accelerating reference frames can't have conservation of energy directly applied to them. (There are way to do it, but aren't worth the effort.)
It does not matter anyway, because no matter what happens in the device frame, it does not change the fact that it is trivial to turn such a device into a power generator by having it accelerate and then extracting the kinetic energy.
There are ways to explain this from the device taking energy from somewhere or something else, or even that energy conservation simply does not hold. Before considering the implications of any of these, the fact of using the device to generated energy must be accepted. Talking about energy conservation in the instantaneous rest frame is simply a way to ignore the issue.
I will not bother responding to TT directly, since TT has not addressed the simple fact that his last spreadsheet he shared did not even have the proper units in the energy calculation. The Pluto spreadsheet he has since shared a screenshoot of seems to have been further changed presumably to remove any remaining resemblance to the laws of physics.
Hi Meberbs,
Pluto mission graphic and spreadsheet ver 9 attached.
From what I see the max V midway flip point KE Js are less than the total Rf input Js, based on the starting point zero velocity reference frame. So no OU here.
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#907 by meberbs on 18 Aug, 2017 20:48
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Hi Meberbs,
The issue is that you have misrepresented the data. There is only one force applied to the cavity. All of your calculations are based on the Fd value and the Fs is not used for anything. The real Ts value is therefore 0.92/20 = 0.046 N/kW. This specific thrust value reaches over unity at slightly more than 40000 m/s, just beyond what you have in your spreadsheet.
Pluto mission graphic and spreadsheet ver 9 attached.
You may be tricking yourself by the way your spreadsheet is setup so that this real Ts value decreases as you pick larger final velocities. This is clearly nonsensical, because the emDrive would have to know in advance how long it will run for before determining the force that will be output. -
#908 by TheTraveller on 18 Aug, 2017 21:22
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Hi Meberbs,
The issue is that you have misrepresented the data. There is only one force applied to the cavity. All of your calculations are based on the Fd value and the Fs is not used for anything. The real Ts value is therefore 0.92/20 = 0.046 N/kW. This specific thrust value reaches over unity at slightly more than 40000 m/s, just beyond what you have in your spreadsheet.
Pluto mission graphic and spreadsheet ver 9 attached.
You may be tricking yourself by the way your spreadsheet is setup so that this real Ts value decreases as you pick larger final velocities. This is clearly nonsensical, because the emDrive would have to know in advance how long it will run for before determining the force that will be output.
Hi Meberbs,
Modified the work equation to use the derated Fd. Now work = KE as it should.
If you modify Green dV to 40,000 m/s, you must use goal seek on Green seconds to get calculated Yellow dV to match Green dV. Doing that increases seconds and increases Rf input energy.
Just did it that and the results are 2.724x10^12 Rf J in and 2.4x10^12 KE J out. However mid point is then 2.724x10^9km and we want it to be 2.317x10^9km. So a dV of 40,000 m/s is too large but still not OU.
The Fs value is the Static Thrust, ie doing no work thrust, or 0.326N/kW * 20 kW = 6.52N which implies no cavity energy is lost being converted into work and KE.
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#909 by Monomorphic on 18 Aug, 2017 21:32
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I'm pretty happy with how the small end-plate turned out after applying the EMI shielding copper adhesive foil. This piece has more curvature per unit of distance compared to the big end-plate.
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#910 by meberbs on 18 Aug, 2017 21:34
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My response is unchanged. You did not address a single thing I said.Hi Meberbs,
The issue is that you have misrepresented the data. There is only one force applied to the cavity. All of your calculations are based on the Fd value and the Fs is not used for anything. The real Ts value is therefore 0.92/20 = 0.046 N/kW. This specific thrust value reaches over unity at slightly more than 40000 m/s, just beyond what you have in your spreadsheet.
Pluto mission graphic and spreadsheet ver 9 attached.
You may be tricking yourself by the way your spreadsheet is setup so that this real Ts value decreases as you pick larger final velocities. This is clearly nonsensical, because the emDrive would have to know in advance how long it will run for before determining the force that will be output.
Hi Meberbs,
Modified the work equation to use the derated Fd. Now work = KE as it should.
If you modify Green dV to 40,000 m/s, you must use goal seek on Green seconds to get calculated Yellow dV to match Green dV. Doing that increases seconds and increases Rf input energy.
Just did it that and the results are 2.724x10^12 Rf J in and 2.4x10^12 KE J out. However mid point is then 2.724x10^9km and we want it to be 2.317x10^9km. So a dV of 40,000 m/s is too large but still not OU.
the closest you came to addressing a point is where you said you used the "derated Fd," but you didn't change Ts to match. 40000 m/s, I said that it is slightly more than that. If you go back to my other posts, you would find the relevant formula for the actual answer, but remember you have to use the actual physical force, not the meaningless "Fs" for calculating Ts.
Edit: got the meaningless subscripts backwards. -
#911 by TheTraveller on 18 Aug, 2017 21:44
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My response is unchanged. You did not address a single thing I said.Hi Meberbs,
The issue is that you have misrepresented the data. There is only one force applied to the cavity. All of your calculations are based on the Fd value and the Fs is not used for anything. The real Ts value is therefore 0.92/20 = 0.046 N/kW. This specific thrust value reaches over unity at slightly more than 40000 m/s, just beyond what you have in your spreadsheet.
Pluto mission graphic and spreadsheet ver 9 attached.
You may be tricking yourself by the way your spreadsheet is setup so that this real Ts value decreases as you pick larger final velocities. This is clearly nonsensical, because the emDrive would have to know in advance how long it will run for before determining the force that will be output.
Hi Meberbs,
Modified the work equation to use the derated Fd. Now work = KE as it should.
If you modify Green dV to 40,000 m/s, you must use goal seek on Green seconds to get calculated Yellow dV to match Green dV. Doing that increases seconds and increases Rf input energy.
Just did it that and the results are 2.724x10^12 Rf J in and 2.4x10^12 KE J out. However mid point is then 2.724x10^9km and we want it to be 2.317x10^9km. So a dV of 40,000 m/s is too large but still not OU.
the closest you came to addressing a point is where you said you used the "derated Fd," but you didn't change Ts to match. 40000 m/s, I said that it is slightly more than that. If you go back to my other posts, you would find the relevant formula for the actual answer, but remember you have to use the actual physical force, not the meaningless "Fs" for calculating Ts.
Edit: got the meaningless subscripts backwards.
Fs is not used.
The derated and smaller Fd is what does the work, accelerates the mass and increases KE.
Acceleration is Fd (c13) / m (c6).
Please check the equation in c16 to confirm. -
#912 by meberbs on 18 Aug, 2017 22:05
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Fs is not used.
Of course it is not used, that was my point. Fs has no meaning. You need to adjust your Ts to reflect the actual force, which is what you call Fd.
Then you can go back and check what velocity overunity will be reached in the initial rest frame. -
#913 by TheTraveller on 18 Aug, 2017 22:23
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Fs is not used.
Of course it is not used, that was my point. Fs has no meaning. You need to adjust your Ts to reflect the actual force, which is what you call Fd.
Then you can go back and check what velocity overunity will be reached in the initial rest frame.
Fs has a meaning. It is the no load or no work being done thrust value and Fd is the loaded or work being done thrust value. As cavity energy is drawn off and used to do work, increase V and KE, the cavity Q drops and thus force drops.
Just like a battery that drops voltage as current is drawn. No one would calc watts as no load voltage * loaded current. Instead watts is loaded voltage * loaded current.
So acceleration is Fd / m and not Fs / m as Fs / m would generate a higher than reality acceleration.
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#914 by Flyby on 18 Aug, 2017 22:41
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These charts aren't doing any favors to anyone without proof of the cited thrust figures. As of this posting, there's still no proof of a device that produces an anomalous force in the double digit millinewtons per kilowatt. Why shouldn't we dismiss the enormous figures as rambling claptrap?
While you are free to dismiss such numbers or that they've been adequately proven, it's not that such numbers haven't been amply reported as they have been. So, we should be able to discuss them here.
In all honesty Bob, even I as layman can tell that graph is worthless :
1/ Not enough sampling
2/comparing different configurations and setups really is "comparing apples and oranges"
What has been done there in that graph , is basically comparing diesel engines, with petrol engines, jet engines and rocket boosters while researching the best fuel..
The first rule to make a comparative listing is that only vary 1 parameter in design:
fe if you want to compare different fuels, you try the same rocket engine setup up with ethanol+O2, methanol+O2, kerosene+O2, etc and then see what produces the most thrust...
So, if any meaningful graph needs to be produced for the EMdrive, you have to use the SAME design and gradually ramp up the power and measure the reaction forces (if any).
The listing Shawyer has provided us is purely for marketing purposes in an attempt to get an opinion or believe across to the audience but can not be considered "proof".
It is in a way, dishonest to pretend it is a factual data sheet, where in fact it is nothing more pile of random info...
Hardly anything can be learned from that, because it is obscured by a zillion changing parameters... -
#915 by TheTraveller on 18 Aug, 2017 22:50
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These charts aren't doing any favors to anyone without proof of the cited thrust figures. As of this posting, there's still no proof of a device that produces an anomalous force in the double digit millinewtons per kilowatt. Why shouldn't we dismiss the enormous figures as rambling claptrap?
While you are free to dismiss such numbers or that they've been adequately proven, it's not that such numbers haven't been amply reported as they have been. So, we should be able to discuss them here.
In all honesty Bob, even I as layman can tell that graph is worthless :
1/ Not enough sampling
2/comparing different configurations and setups really is "comparing apples and oranges"
What has been done there in that graph , is basically comparing diesel engines, with petrol engines, jet engines and rocket boosters while researching the best fuel..
The first rule to make a comparative listing is that only vary 1 parameter in design:
fe if you want to compere different fuels, you try the same engine setup up with ethanol+O2, methanol+O2, kerosene+O2, etc and then see what produces the most thrust...
So, if any meaningful graph needs to be produced for the EMdrive, you have to use the SAME design and gradually ramp up the power and measure the reaction forces (if any).
The listing Shawyer has provided us is purely for marketing purposes in an attempt to get an opinion or believe across to the audience but can not be considered "proof".
It is in a way, dishonest to pretend it is a factual data sheet, where in fact it is nothing more pile of random info...
Hardly anything can be learned from that, because it is obscured by a zillion changing parameters...
Hi Flyby,
Maybe review the Flight Thruster test data?
http://www.emdrive.com/flightprogramme.html
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#916 by meberbs on 18 Aug, 2017 23:16
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Fs has a meaning. It is the no load or no work being done thrust value and Fd is the loaded or work being done thrust value.
It is entirely possible for a device to produce different forces in different situations, however, the only force that matters is the force it is actually producing in the situation it is in. The only reasonable definition of Ts uses the actual force Fd.
Now, go back and do the calculations again using a velocity based on the last formula in this post such that the last expression is greater than 1. Don't forget to make sure the actual Ts value of Fd/P is fixed. It doesn't make sense for this value to depend on at what point in the future the drive is turned off.
Edit, typo'd the subscript again. -
#917 by Rodal on 18 Aug, 2017 23:22
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... It doesn't make sense for this value to depend on at what point in the future the drive is turned off.
and if somebody assumes for the present value to depend on future (yet unknown) states, it is essentially assuming knowledge of the future state: requiring superluminal communication, as with tachyons conveying future information and breaking causality...
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#918 by Flyby on 18 Aug, 2017 23:30
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TT,
that is indeed more as it should be presented as, at least in this case, I do not get the feeling I'm being fooled or toyed with.
But do you really think that 10 up/ 9 down samples is enough to extrapolate data to 6 magnitudes bigger (we're now at 1540N/kW, right ?)
It is like using a 1m ruler to aim at a target 1000km further away...
Considering the small sampling range, I still find such an huge and far extrapolation rather unbelievable...
As it is, the data gives us an indication of what is happening between 150W and 450W.
It basically show the relation between power and resulting forces. There are a lot of other possibilities that can produce such relation power/force.
In all honesty, it would be way more convincing if the relation between forces and Q could be demonstrated, as that would most likely eliminate any thermal effect (that would remain constant, for a given fixed power input)
If only the relation between Q and resulting forces could be demonstrated with an almost identical system...that would go a good way to remove some of the doubts... -
#919 by otlski on 19 Aug, 2017 01:04
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I've been working on blocking out a USC/ARC style thrust balance that can handle something as massive as an emdrive plus electronics and battery. This design can accommodate my current 2.4GHz TE013 frustum, which is fairly large as emdrives go. No need to worry about galistan contacts as the on-board 12V Lipo battery is good for ~40 minutes of testing. As I have a lot of aluminum lying around already, the only custom pieces I need are the telescoping tubes for the center of the balance arms.
As for the base foundation. Jim Woodward and Heidi Fearn used thick acrylic, while others have recommended a solid aluminum optical breadboard. Acrylic is about half the cost of the optical breadboard. I expect with a prototype thrust balance, it may be a challenge to get the custom parts to align with the optical breadboard's pre-drilled holes, but it is very easy to drill holes through acrylic. So i'm trying to decide between the two. Any thoughts?
I would use aluminum for the entire mechanism sans the draft shield. The flexures you would like to use really want to be coaxial to 0.005" in tilt and translation. We typically try for half that using precision ground Thompson rod to achieve alignment. What this means is that you really want to bore the flexure mounts to exact size and perpendicularity so aluminum and steel are your best bets. Given that aluminum is easier to machine (also less parasitic mass) it would be my choice. After that, I would want to CTE match as much of the remaining mechanism as possible; meaning all aluminium for the rest too.
Once again, the levels of force, whether EM or artifacts, demand that nothing be taken for granted in the instrument, and that CTE matching gives you one less thing to concern yourself with. Obviously CTE matching only helps with differential expansion due to material types. It does not help with differential expansion due to thermal-mass vs. time, or with the fact that the components will still grow/shrink overall.
Attached is a Sartorius monoblock mechanism machined from one piece of aluminum. These force restoration transducers have over 1,000,000:1 dynamic range for a COTS electro-mechanical device. This is a twenty fold improvement over say circa 1985 Sartorius devices which had a mix of steel, aluminium, brass, and other metals pieced together to provide the same function the monoblock does.
