Well, BfX is updated (since one week)

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200 mph

without drag 2692 m

with drag 2387 m

x y z t v vx vy vz

0 0,00 0,00 5059,680 0,000 89,408 88,050 0,000 -15,526

1 200,00 0,00 4998,807 2,292 94,227 86,438 0,000 -37,513

2 400,00 0,00 4885,409 4,629 103,463 84,688 0,000 -59,436

3 600,00 0,00 4717,281 7,018 115,917 82,721 0,000 -81,203

4 800,00 0,00 4491,775 9,469 130,467 80,473 0,000 -102,692

5 1000,00 0,00 4205,627 11,994 146,228 77,893 0,000 -123,754

6 1200,00 0,00 3854,735 14,610 162,521 74,936 0,000 -144,214

7 1400,00 0,00 3433,860 17,340 178,802 71,558 0,000 -163,859

8 1600,00 0,00 2936,196 20,211 194,594 67,713 0,000 -182,433

9 1800,00 0,00 2352,714 23,262 209,427 63,355 0,000 -199,615

10 2000,00 0,00 1671,090 26,546 222,788 58,425 0,000 -214,990

11 2200,00 0,00 873,873 30,139 234,058 52,859 0,000 -228,011

12 2400,00 0,00 -64,949 34,162 242,440 46,577 0,000 -237,923

without drag 2692 m

with drag 2387 m

x y z t v vx vy vz

0 0,00 0,00 5059,680 0,000 89,408 88,050 0,000 -15,526

1 200,00 0,00 4998,807 2,292 94,227 86,438 0,000 -37,513

2 400,00 0,00 4885,409 4,629 103,463 84,688 0,000 -59,436

3 600,00 0,00 4717,281 7,018 115,917 82,721 0,000 -81,203

4 800,00 0,00 4491,775 9,469 130,467 80,473 0,000 -102,692

5 1000,00 0,00 4205,627 11,994 146,228 77,893 0,000 -123,754

6 1200,00 0,00 3854,735 14,610 162,521 74,936 0,000 -144,214

7 1400,00 0,00 3433,860 17,340 178,802 71,558 0,000 -163,859

8 1600,00 0,00 2936,196 20,211 194,594 67,713 0,000 -182,433

9 1800,00 0,00 2352,714 23,262 209,427 63,355 0,000 -199,615

10 2000,00 0,00 1671,090 26,546 222,788 58,425 0,000 -214,990

11 2200,00 0,00 873,873 30,139 234,058 52,859 0,000 -228,011

12 2400,00 0,00 -64,949 34,162 242,440 46,577 0,000 -237,923

#213

And if the engine does not deforms hitting the ground, it could travel as much as 16 m in the soil!

(based on a very naive estimation).

(based on a very naive estimation).

#214

Jan,

working in the metric system has many advantages, so I did convert everything to that system first (see the Excel spreadsheet that was included in the previous post):

convert to metric velocity components

height dropped 16600 ft 5059,68 m vx= 105,6596299 m/s

velocity dropped 240 mph 107,2896 m/s vz= -18,63064352 m/s

angle -10 degrees -0,174532925 rad

Then without air drag one can almost compute the distance where the engine hits the ground without any computers ... if one rounds off the numbers t^2=5000 *2 /10=1000, t=32s. Distance travelled=32*100=3200m

The 10 degrees is taken in account (vx vz), but that does not changes the impact zone much.

More accurately, but still for the case of no airdrag, one has to solve an equation like

z(t)=5059-18,6*t-0,5*9,81*t2

if you do that then

Z(t) z -5,50723E-06 m t 30,27447353 s

x(t) 3198,789668 m

What about air drag?

I have made an estimate of what the ballistic coefficient (measure of drag) could be, put it into the computer program and got the table. I changed the values of the coefficient and looked at their effect. Then, convinced, I fixed the coefficient and presented the results in the previous post.

This is the educated guess, there could be some more drag, but there has to be a lot of drag before the engine hits the ground at 2km. If the motor started spinning then this might be the case. However, I think that it is very likely that you find the motor at 2,5-3 km.

Where was the motor lost?

working in the metric system has many advantages, so I did convert everything to that system first (see the Excel spreadsheet that was included in the previous post):

convert to metric velocity components

height dropped 16600 ft 5059,68 m vx= 105,6596299 m/s

velocity dropped 240 mph 107,2896 m/s vz= -18,63064352 m/s

angle -10 degrees -0,174532925 rad

Then without air drag one can almost compute the distance where the engine hits the ground without any computers ... if one rounds off the numbers t^2=5000 *2 /10=1000, t=32s. Distance travelled=32*100=3200m

The 10 degrees is taken in account (vx vz), but that does not changes the impact zone much.

More accurately, but still for the case of no airdrag, one has to solve an equation like

z(t)=5059-18,6*t-0,5*9,81*t2

if you do that then

Z(t) z -5,50723E-06 m t 30,27447353 s

x(t) 3198,789668 m

What about air drag?

I have made an estimate of what the ballistic coefficient (measure of drag) could be, put it into the computer program and got the table. I changed the values of the coefficient and looked at their effect. Then, convinced, I fixed the coefficient and presented the results in the previous post.

This is the educated guess, there could be some more drag, but there has to be a lot of drag before the engine hits the ground at 2km. If the motor started spinning then this might be the case. However, I think that it is very likely that you find the motor at 2,5-3 km.

Where was the motor lost?

#215

Jan, after some thoughts, it isn't too difficult.

You made an error in your calculations. The better formula for the height as function of time : z(t) = z0-vz*t-0,5*9,81*t^2

vx=106 m/s

vz=18,6 m/s

In absence of air resistance the engine falls 30,2 s and travels 3198 m

With air resistance ... I made the following calculation ...

the engine falls about 34 s and travels about 2820 m

(It was done by a computer program that is not downloadable)

included a spreadsheet with the calculations

Robert

m m m s m m/s m/s m/s

x y z t v vx vy vz

0 0 0 5059,68 0 107,2896 105,6596299 0 -18,63064352

1 200 0 5006,632916 1,91011851 110,0991639 103,7476291 0 -36,85451598

2 400 0 4917,130465 3,856500547 115,684911 101,7493745 0 -55,04601183

3 600 0 4789,722193 5,842786049 123,5918684 99,61176624 0 -73,16041258

4 800 0 4622,758705 7,874016067 133,3068689 97,28770152 0 -91,13629582

5 1000 0 4414,321708 9,956771129 144,3379402 94,73571952 0 -108,8971277

6 1200 0 4162,139533 12,09939126 156,2491124 91,91865116 0 -126,3516787

7 1400 0 3863,480602 14,31232618 168,6631164 88,80195378 0 -143,3926771

8 1600 0 3515,013049 16,60867491 181,2484026 85,35206006 0 -159,8937437

9 1800 0 3112,612007 19,00500448 193,7007394 81,53484683 0 -175,7044257

10 2000 0 2651,084582 21,5225951 205,7235961 77,31419936 0 -190,6428928

11 2200 0 2123,761651 24,18937213 217,0078103 72,65058728 0 -204,4854075

12 2400 0 1521,865416 27,04300366 227,2089519 67,49953732 0 -216,9509629

13 2600 0 833,4792567 30,13609712 235,919091 61,80985336 0 -227,6781929

14 2800 0 41,76410461 33,54545389 242,6270797 55,52136465 0 -236,1890723

You made an error in your calculations. The better formula for the height as function of time : z(t) = z0-vz*t-0,5*9,81*t^2

vx=106 m/s

vz=18,6 m/s

In absence of air resistance the engine falls 30,2 s and travels 3198 m

With air resistance ... I made the following calculation ...

the engine falls about 34 s and travels about 2820 m

(It was done by a computer program that is not downloadable)

included a spreadsheet with the calculations

Robert

m m m s m m/s m/s m/s

x y z t v vx vy vz

0 0 0 5059,68 0 107,2896 105,6596299 0 -18,63064352

1 200 0 5006,632916 1,91011851 110,0991639 103,7476291 0 -36,85451598

2 400 0 4917,130465 3,856500547 115,684911 101,7493745 0 -55,04601183

3 600 0 4789,722193 5,842786049 123,5918684 99,61176624 0 -73,16041258

4 800 0 4622,758705 7,874016067 133,3068689 97,28770152 0 -91,13629582

5 1000 0 4414,321708 9,956771129 144,3379402 94,73571952 0 -108,8971277

6 1200 0 4162,139533 12,09939126 156,2491124 91,91865116 0 -126,3516787

7 1400 0 3863,480602 14,31232618 168,6631164 88,80195378 0 -143,3926771

8 1600 0 3515,013049 16,60867491 181,2484026 85,35206006 0 -159,8937437

9 1800 0 3112,612007 19,00500448 193,7007394 81,53484683 0 -175,7044257

10 2000 0 2651,084582 21,5225951 205,7235961 77,31419936 0 -190,6428928

11 2200 0 2123,761651 24,18937213 217,0078103 72,65058728 0 -204,4854075

12 2400 0 1521,865416 27,04300366 227,2089519 67,49953732 0 -216,9509629

13 2600 0 833,4792567 30,13609712 235,919091 61,80985336 0 -227,6781929

14 2800 0 41,76410461 33,54545389 242,6270797 55,52136465 0 -236,1890723

#216

Jan,

interesting question, could be a question of my father too! I think I can make an educated guess and produce a spreadsheet for you.

However, I have first to pounder about the issue - what is the drag of an motor, and then make some calculations. This costs me about one or two weeks - I have so many other things to do - but I will do it.

It would greatly help if you have some data from similcar cases, even bomb trajectories.

Robert

interesting question, could be a question of my father too! I think I can make an educated guess and produce a spreadsheet for you.

However, I have first to pounder about the issue - what is the drag of an motor, and then make some calculations. This costs me about one or two weeks - I have so many other things to do - but I will do it.

It would greatly help if you have some data from similcar cases, even bomb trajectories.

Robert

#217

I have updated most of the downloads,

See the GettingStarted workbook for explanations

Furthermore, most workbooks are somewhat improved

- BfX.xll includes now BfX_Cd that allows you to extract the drag function values that BfX uses
- The previous drag function RA contained in BfX overestimated the drag around the speed of sound and has been replaced
- BfX_I interpolates smarter and is able to show some additional information how accurate and how the results are interpolated

See the GettingStarted workbook for explanations

Furthermore, most workbooks are somewhat improved

#218

Users of BfX,

Beginning of may I will release an update of BfX.

I worked a bit on BfX_I so that it can cope with more situations. The function also yield info on the quality of each interpolation.

I improved the implementation of the RA4 (small bore, .22LR) drag function. Due to an error, the one currently in use has to much drag arround the sound velocity.

Another function was added to BfX that yields the drag coeficient (drag function) as a function of bullet velocity for G1, G2.... One use for this is that BfX drag coeficients can be checked with others.

Some Excel filles in the download section will be updated to reflect the new functionality.

Robert

Beginning of may I will release an update of BfX.

I worked a bit on BfX_I so that it can cope with more situations. The function also yield info on the quality of each interpolation.

I improved the implementation of the RA4 (small bore, .22LR) drag function. Due to an error, the one currently in use has to much drag arround the sound velocity.

Another function was added to BfX that yields the drag coeficient (drag function) as a function of bullet velocity for G1, G2.... One use for this is that BfX drag coeficients can be checked with others.

Some Excel filles in the download section will be updated to reflect the new functionality.

Robert

#220

I you don't succeed I'll do it for you.

#221

and if you know the muzzle velocity then you can remove it from solver.

#222

Ja,

I provided a worksheet that is doing exactly that already - calculating from velocity and distances a bc. Look at the download page at

"Show me how Solver can be used with BfX VBA?"

However, a much simpler version is attached to the post.

Robert

I provided a worksheet that is doing exactly that already - calculating from velocity and distances a bc. Look at the download page at

"Show me how Solver can be used with BfX VBA?"

However, a much simpler version is attached to the post.

Robert

#223

I have tried that, but after some experiments (including some dedicated interfaces in bfx.xll) I got stuck. It is certainly possible and I have to say that I spend not too much time on this.

It is quite easy for me to add another set of interfaces to bfx.xll to support vb.net, however I was looking for some general purpose data types like variants (or the xltype of Excel) for easy usage and to have the flexibility of using optional arguments i.e. to support a vb call like v=bfx_vx(700, 30, 0.5) and v=bfx_vx(700, 30, "yd", 0,5). So after some trying I paused my developments there. Furthermore array passing and accessing should be friendly for the programmer. bfx.xll runs in an unmanaged environment, not int the .net engine - adding additional levels of complexity.

If you know a receipy for this then I am quite willing to implement such interfaces.

Robert

It is quite easy for me to add another set of interfaces to bfx.xll to support vb.net, however I was looking for some general purpose data types like variants (or the xltype of Excel) for easy usage and to have the flexibility of using optional arguments i.e. to support a vb call like v=bfx_vx(700, 30, 0.5) and v=bfx_vx(700, 30, "yd", 0,5). So after some trying I paused my developments there. Furthermore array passing and accessing should be friendly for the programmer. bfx.xll runs in an unmanaged environment, not int the .net engine - adding additional levels of complexity.

If you know a receipy for this then I am quite willing to implement such interfaces.

Robert

#224

Well,

the forum is online again. See if we are less popular for persons who want to sell things.

Robert

the forum is online again. See if we are less popular for persons who want to sell things.

Robert

#225

The forum is finally online!

After years of more less then more working at the physics and software of BfX.xll - the Excel 2003 and 2007 addin - and a month or so on the website and forum, I decided to put it all online. My main motivation for providing the BfX.xll is that I thought that the software is as useful to fellow match shooters as it turned out for myself. BfX is great for the calculations of sight settings and in the analysis of the effects of wind.

Do not hesistate to post, although I realy do not know what to expect!

Robert

After years of more less then more working at the physics and software of BfX.xll - the Excel 2003 and 2007 addin - and a month or so on the website and forum, I decided to put it all online. My main motivation for providing the BfX.xll is that I thought that the software is as useful to fellow match shooters as it turned out for myself. BfX is great for the calculations of sight settings and in the analysis of the effects of wind.

Do not hesistate to post, although I realy do not know what to expect!

Robert