Umarex Notos Porting
- Thread starter caliusoptimus
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Not using Hooke's law then? Hmm.
Also this method suggests hammer pre-load simply doesn't matter, I still cannot follow, maybe I am just not smart enough.
-Matt
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I am using Hooke's law to calculate the Newton Energy transferred to the hammer. From that you use this method to calculate hammer velocity. However, it is very possible my calculation is not 100% and I may have to revisit the conversion.
sciencing.com
-Matt
How to Calculate Contact Force
Contact forces, as the name implies, result from objects that make direct contact with one another rather than acting at a distance.
sciencing.com -Matt
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Yea my calculations are lining up entirely...idk man
Maybe my conversion from m/s^2 is not right? Hmm
-Matt
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Hookes law is used in b37 and b39.Not using Hooke's law then? Hmm.
Also this method suggests hammer pre-load simply doesn't matter, I still cannot follow, maybe I am just not smart enough.
-Matt
Add 2mm to both the cocked and decocked spring length inputs to see the effect of backing out the hammer spring adjuster.
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No where on your sheet do I see this value...
Force (F) = 62....Nor the acceleration of 3388 M/S^2....which from force you can derive acceleration, which from that you can derive..velocity.
-Matt
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Velocity is derived from the energy. An ideal spring will require x energy to compress and will release x energy when released. The hammer will receive x energy from the spring. Calculate velocity from mass and energy. This is a perfect and ideal situation. Real world will be less, but your spreadaheet shows more. Why?
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So your current calculation suggests .0787/2mm added preload only gains .05 FPE, from .62 to .67...... We're talking the difference of 14 lbs force to cock, to 22 lbs force to cock due to that preload change, which is a 57% increase, but your calculating only an 8% increase in energy transfer? Hmm.
I suppose its possible, just can't wrap my head around that.
-Matt
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As I said, I am probably converting m/s^2 to fps incorrectly some how, but I am unsure. You cannot calculate velocity from mass and energy alone afaik, you need to know the acceleration, and to get acceleration you need to know the mass and force, which I showed above I am calculating correctly.
Your force is 62 newtons, and acceleration is 3388 m/s^2.
-Matt
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I'll make some changes to my sheet with the data you provided, I appreciate you pointing out the flaw, my approach is very complex and requires more than I care to deal with right now using force x acceleration, I'll have to revisit it sometime.
I still can't wrap my head around how 57% increase in force to compress a spring would result in only 8-9% more energy transferred to the hammer....that one really hurts my brain.
How would you incorporate hammer gap or free flight into your equation?
-Matt
I still can't wrap my head around how 57% increase in force to compress a spring would result in only 8-9% more energy transferred to the hammer....that one really hurts my brain.
How would you incorporate hammer gap or free flight into your equation?
-Matt
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Using your method however, I made the user inputs a bit more 'user friendly'....thanks again for sharing. Not sure how I'd include hammer gap with your method though. I'll have to ponder on that for a bit as well as fixing my old approach unless you have an idea how to include hammer gap/free flight with yours.
-Matt
-Matt
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Using this method to calculate velocity from Force and Distance
sciencing.com
I still arrive at what I am currently at!!! Simply using 62 newtons and .75" or 19mm travel distance with 18.9 grams of hammer, I arrive at 36 FPS hammer velocity. So I am using two different methods to calculate velocity of the hammer, and both state 36 fps...man...I need a drink! Lol
-Matt
How to Calculate Work Input in a Pulley
Every natural event has an equation to determine its outcome. When two objects come together to produce work, the energy generated by one object may need to be multiplied to affect the other. Pulley systems multiply force. Work creates force, and though force may be multiplied by the use of...
sciencing.com I still arrive at what I am currently at!!! Simply using 62 newtons and .75" or 19mm travel distance with 18.9 grams of hammer, I arrive at 36 FPS hammer velocity. So I am using two different methods to calculate velocity of the hammer, and both state 36 fps...man...I need a drink! Lol
-Matt
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Complicated for sure. I'm keeping it as simple as possible unless I find a real need to do more. What I have now seems good enough to help me select different springs.
That doesn't seem right. Using the notos example numbers the spring is 1.96N/mm... so increasing the preload by 2mm would only increase the force by 3.92N (.88lbf). And doing so would increase potential energy from .618fpe to .673fpe.
For the purpose of finding the spring's potential energy it's already in there. As far as the interaction with the valve... no idea.
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Hammer free flight gap will change the velocity of the hammer interacting with the valve, which is important in calculating the FPE upon contact...
Good watch for ya. This might explain why I take the approach I do which is using spring force...opposed to the approach you have taken with potential energy.
-Matt
Good watch for ya. This might explain why I take the approach I do which is using spring force...opposed to the approach you have taken with potential energy.
Avoid the Common Pitfall of Confusing Elastic Potential Energy VS Elastic Spring Force
-Matt
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My apologies on that one, I moved a decimal place over on the conversion to mm to inch, so I calculated 8.8 opposed to .88, which is a 5% change, yet you're still calculating a 9% increase in energy from 5% increase in preload, still hard to wrap my head around it, how are you creating more energy than what you're increasing in the spring?
My current approach calculates...a 5% increase in energy from the 5% increase in preload...seems valid no? Also my current approach makes it very easy to integrate hammer gap / free flight, however with yours, I cannot fathom how one would.
-Matt
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One of the key differences between your approach and mine on calculating hammer data, is you're obtaining hammer velocity from potential spring energy and hammer mass, and I am obtaining energy from velocity, and using force * distance with hammer mass. Both utilize hookes law...online calculators give me the same newton force results as I obtain...
Now here is where I get confused, and I am not saying anything more on the matter for now, as I have concluded that...dis be bonkers.
11.2 m/s = 36.7 fps, which is exactly what I have been calculating, however..
Which is exactly what @caliusoptimus arrives at using his method.
Now I am very inclined to believe caliusoptimus, because it works out with the potential energy of a spring, however, the above calculation isn't wrong either...nor were my conversions. In the end, hopefully this explains some hows/whys. I was busy looking for conversion errors, and decided to let ChatGPT calculate using both methods. Now, time to science the heck out of these calculations some day...lol
-Matt
Now here is where I get confused, and I am not saying anything more on the matter for now, as I have concluded that...dis be bonkers.
11.2 m/s = 36.7 fps, which is exactly what I have been calculating, however..
Which is exactly what @caliusoptimus arrives at using his method.
Now I am very inclined to believe caliusoptimus, because it works out with the potential energy of a spring, however, the above calculation isn't wrong either...nor were my conversions. In the end, hopefully this explains some hows/whys. I was busy looking for conversion errors, and decided to let ChatGPT calculate using both methods. Now, time to science the heck out of these calculations some day...lol
-Matt
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I was thinking about how to determine lock time awhile back. Just a curiosity thing in my head, no real need to apply it.
I figured I could get the final velocity easily enough by figuring energy (work) and then using the mass, determine velocity from that.
Where I stopped trying to figure out my approach was when it came to actual lock time, final velocity wasn’t going help me much. I don’t think you can use (final + initial)/2 to determine average velocity because the rate of acceleration is not constant, it’s decaying through the distance.
I didn’t pursue the question further because I had no real world application at the time. I figured if I really wanted to know, I would set up some sensors and measure with the oscilloscope, lol.
Dave
I figured I could get the final velocity easily enough by figuring energy (work) and then using the mass, determine velocity from that.
Where I stopped trying to figure out my approach was when it came to actual lock time, final velocity wasn’t going help me much. I don’t think you can use (final + initial)/2 to determine average velocity because the rate of acceleration is not constant, it’s decaying through the distance.
I didn’t pursue the question further because I had no real world application at the time. I figured if I really wanted to know, I would set up some sensors and measure with the oscilloscope, lol.
Dave
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The exponent in hookes law suggests that it's not a linear relationship.
I'd guess it's probably a lot like an RC time curve (in electronics). Velocity would be current flow when charging a capacitor.
But math is hard and I'm probably wrong.
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Wouldn't you need initial velocity + final velocity and the rate of acceleration as shown in the below calculator to determine the time?
Velocity Calculator
Use the velocity calculator to assess how fast an object moves, given a certain distance and time.
www.omnicalculator.com -Matt
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Yeah, but in my mind, the rate of acceleration is not a constant. You can’t just plug in a number like you could if acceleration were constant. I only get that from F=ma and the force is constantly changing.
Dave
Dave
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