fin cross sections for Mach3+

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cjl,

The assertion that "Nothing we do in amateur rocketry is likely to ever fall under that umbrella." (ITAR and EAR) makes me think you haven't read the regs. Export can and often is transfer of information to a non-US national. Take a look at what is on the United States Munitions List (USML).

That something is well known abroad doesn't provide license for a US person to talk about it with internationals. Sorry. I didn't write the rules, but I have to abide by them.

Gerald

But OP asserts he is a passport holding US citizen, correct? So it's a big nothing burger in this instance, right?


Sad +1, that's why all the *nix crypto libraries were hosted outside the US for the longest, strangest time. It made no sense, but we needed to comply.

And yet you were able to legally use those crypto libraries in the USA despite the fact they were hosted in Canada, right? I'm not sure what you're trying to assert here other than maybe Mach 3+ specific knowledge regarding rocketry should be hosted outside of the USA?

For the record I'm in the same boat as the OP. Specifically I'm a US citizen living abroad. There are quite a few of us in fact...
 
And yet you were able to legally use those crypto libraries in the USA despite the fact they were hosted in Canada, right? I'm not sure what you're trying to assert here other than maybe Mach 3+ specific knowledge regarding rocketry should be hosted outside of the USA?

Yes, in that specific scenario importing or using crypto ( mostly from Europe ) was permitted but exporting was not.

I'm not trying to assert anything other than the law isn't necessarily sensible nor even consistent.

I definitely don't have a suggestion on where physically to host content that may be covered by ITAR as I assume other countries likely have similar restrictions with which I am entirely unfamiliar.
 
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Mach 3 data does not fall under that umbrella though. In fact, from what I can find in the USML, the only mention of any aerodynamic restriction at all is as follows:

Specially designed software, or specially designed software with related specially designed hybrid (combined analog/digital) computers, for modeling, simulation, or design integration of the systems in Item 1 and Item 2

Looking back at item 1 and item 2, we have the following:
Item 1:
Complete rocket systems (including ballistic missile systems, space launch vehicles, and sounding rockets (see § 121.1, Cat. IV(a) and (b))) and unmanned air vehicle systems (including cruise missile systems, see § 121.1, Cat. VIII (a), target drones and reconnaissance drones (see § 121.1, Cat. VIII (a))) capable of delivering at least a 500 kg payload to a range of at least 300 km.

I think it's safe to say that the great majority of hobby rocketry could not deliver 500kg to 300km, so we're good here.

Item 2:
Complete subsystems usable in the systems in Item 1 as follows:
(a) Individual rocket stages (see § 121.1, Cat. IV(h));
(b) Reentry vehicles (see § 121.1, Cat. IV(g)), and equipment designed or modified therefor, as follows, except as provided in Note (1) below for those designed for non-weapon payloads;
(1) Heat shields and components thereof fabricated of ceramic or ablative materials (see § 121.1, Cat. IV(f));
(2) Heat sinks and components thereof fabricated of light-weight, high heat capacity materials;
(3) Electronic equipment specially designed for reentry vehicles (see § 121.1, Cat. XI(a)(7));
(c) Solid or liquid propellant rocket engines, having a total impulse capacity of 1.1×10^6 N-sec (2.5×10^5 lb-sec) or greater (see § 121.1, Cat. IV, (h)).
(d) ‘‘Guidance sets’’ capable of achieving system accuracy of 3.33 percent or less of the range (e.g., a CEP of 1 j,. or less at a range of 300 km), except as provided in Note (1) below for those designed for missiles with a range under 300 km or manned aircraft (see § 121.1, Cat. XII(d));
(e) Thrust vector control sub-systems, except as provided in Note (1) below for those designed for rocket systems that do not exceed the range/payload capability of Item 1 (see § 121.1, Cat. IV);
(f) Warhead safing, arming, fuzing, and firing mechanisms, except as provided in Note (1) below for those designed for systems other than those in Item 1 (see § 121.1, Cat. IV(h))

Notes:
(1) The exceptions in (b), (d), (e), and (f) above may be treated as Category II if the subsystem is exported subject to end use statements and quantity limits appropriate for the excepted end use stated above.
(2) CEP (circle of equal probability) is a measure of accuracy, and defined as the radius of the circle centered at the target, at a specific range, in which 50 percent of the payloads impact.
(3) A “guidance set” integrates the process of measuring and computing a vehicle's position and velocity (i.e., navigation) with that of computing and sending commands to the vehicle's flight control systems to correct the trajectory.
(4) Examples of methods of achieving thrust vector control which are covered by (e) include:
(i) Flexible nozzle;
(ii) Fluid or secondary gas injection;
(iii) Movable engine or nozzle; Deflection of exhaust gas stream (jet vanes or probes); or
(v) Use of thrust tabs.

OK, we still seem pretty safe here, since 1.1e6 newton seconds would be 13 or 14 full P motors. Also, Note 1 seems to confirm that even for things that would normally be restricted (heat shields, guidance sets, and thrust vector control) remain unrestricted if used for applications that fall short of the capabilities enumerated in item 1, so long as appropriate use statements and disclaimers are applied. In other words, there seems to be absolutely no restriction on design and simulation of anything in amateur rocketry due to ITAR.

Now, there is also some stuff in other parts of the USML (category 4 for example) that are more vague, but they generally refer back to these definitions. As far as I can tell, the only things we might regularly run across that would (strangely enough) potentially fall under ITAR would be certain flight computers, which would fall afoul of this provision:

Continuous output accelerometers or gyros of any type, specified to function at acceleration levels greater than 100 g (see § 121.1, Category XII)
 
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Continuous output accelerometers or gyros of any type, specified to function at acceleration levels greater than 100 g (see § 121.1, Category XII

For $25 I can buy a +/- 200G accelerometer break-out board that updates at 500Hz. 5v logic in a 0.75in x 0.75in footprint. 10,000G shock limit too.

ITAR seriously needs to be updated to be somewhat modern. (or really scrapped, but that wont happen)
 
Oh, I agree that it's a stupid restriction. It is, however, still in the regulations, as far as I can tell.
 
PS - That someone asserts something, doesn't make it true. Trust but verify. Sorry, that's the way it would be seen. Again, I didn't make the rules.

Agreed. IANAL, and I trust you aren't either. Also, I find it funny that "trust, but verify" is actually a Russian proverb. Combined with the lack of a Location on your profile I can only assume you are a Russian agent! :lol:
 
Complete subsystems useable in Item 1. I interpret that one line as including airfoil technical data military platform related. The airfoil coordinates in certain specific patterns not discussed here are in systems exceeding those bigger requirements. The airfoil coordinates being a subsystem of a fin subsystem of a missile or rocket stage or other weapon system. The OP is free to talk as OP pleases. But certain things I know, I keep to myself. If you have coordinates you can loft airfoils in modeling programs for example and do engineering simulations in software packages. Remember the design integration part covering 1 and 2. So if it's data being used for military design then get ITAR'd is my guess.

There were mathematical models in US military design software packages for weapons that cover this very topic of biconvex airfoils. Note not one person is posting specific references to military equivalents. The math methods apply power series in math modified ways for special geometry instances the OP is not intending for blunted methods. The OP is freely modifying nosecone equations.
 
I think it's safe to say that the great majority of hobby rocketry could not deliver 500kg to 300km.

The engineering design method in biconvex technology applicable to this requirement in ITAR that you may use in HPR for a non weapon system may have MTCR restrictions. The cross section that is scalable from HPR to ICBM containing military technology of a fin as a subsystem of fin in subsystem of military rocket or ICBM stage whether you make the military rocket or not technology wise. This sucks if math models fall under MTCR rules.
 
Complete subsystems useable in Item 1. I interpret that one line as including airfoil technical data military platform related. The airfoil coordinates in certain specific patterns not discussed here are in systems exceeding those bigger requirements. The airfoil coordinates being a subsystem of a fin subsystem of a missile or rocket stage or other weapon system. The OP is free to talk as OP pleases. But certain things I know, I keep to myself. If you have coordinates you can loft airfoils in modeling programs for example and do engineering simulations in software packages. Remember the design integration part covering 1 and 2. So if it's data being used for military design then get ITAR'd is my guess.

There were mathematical models in US military design software packages for weapons that cover this very topic of biconvex airfoils. Note not one person is posting specific references to military equivalents. The math methods apply power series in math modified ways for special geometry instances the OP is not intending for blunted methods. The OP is freely modifying nosecone equations.
Except that they very clearly enumerate which "complete subsystems" fall under it in the following sections, and aerodynamic data and airfoil performance are not among the details mentioned. Thermal protection systems, thrust vectoring and guidance, rocket stages, and rocket motors in excess of 1.1e6 Ns are included, but aerodynamic data for something as simple as a biconvex airfoil at mach 3, frankly, is so well understood and so far in the public domain that it would be similar to trying to declare ordinary 6061 aluminum subject to ITAR simply because you can make some aircraft components out of it. The math to analyze biconvex airfoils at those speeds has been understood and in college textbooks since at least the 1960s if not earlier.
 
... Part of the MTCR annex is creepy. 22 USC 2797c(a)5 part 7 foreign person means any non United States person. They didn't list citizen it just says person. Why? Then they define "United States person" in other sections. And there are trade restrictions on missile software and technology in development of missiles and aircraft systems. The 2797c(b)2 has language describing the United States retains the right to take action over 2797b(a)2 in case of any export or transfer MTCR technology or equipment that contributes to acquisition, design, developement, or production of missiles in a country not MTcR adherent and would be if the technology were of United States origin.
 
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Mach 3 data does not fall under that umbrella though. In fact, from what I can find in the USML, the only mention of any aerodynamic restriction at all is as follows:................

Chris.......wow.
You've been away awhile.
School all done?
Good to see you back.
 
Chris.......wow.
You've been away awhile.
School all done?
Good to see you back.

Haha, yeah. I've been away quite a while, and I've been staring at all the rocket stuff in my basement thinking I should use it again. I finally made it out to a little local low power launch last weekend and sent up a couple B and C motors, and realized that I definitely should get back to this. I did finish college (and I have a very expensive piece of paper framed on my wall to prove it), and I've been doing the whole gainful employment thing for a few years now. I even get to work with aerodynamics and gigantic composite structures every day, since I'm working for a wind turbine blade design office, so I get to use more balsa and fiberglass than I ever did in rocketry alone. Work and racecars (I got into that after college too) have kept me busy, but I'm hoping to spend more time making it out to launches again, and it's good to be back!
 
NCR instituted a new fee for members who've been away. 1 keg per cert level/per year you were away, payable at MHM, High Skies or O'fest :)

Edward
 
Haha, yeah. I've been away quite a while, and I've been staring at all the rocket stuff in my basement thinking I should use it again. I finally made it out to a little local low power launch last weekend and sent up a couple B and C motors, and realized that I definitely should get back to this. I did finish college (and I have a very expensive piece of paper framed on my wall to prove it), and I've been doing the whole gainful employment thing for a few years now. I even get to work with aerodynamics and gigantic composite structures every day, since I'm working for a wind turbine blade design office, so I get to use more balsa and fiberglass than I ever did in rocketry alone. Work and racecars (I got into that after college too) have kept me busy, but I'm hoping to spend more time making it out to launches again, and it's good to be back!

Is that Jumbo Deuces Wild in the basement?
 
Yes, it absolutely is. I definitely want to fly it again - I was thinking a couple green K's would look really cool.
 
The story really isn't that thrilling (unlike the racing, which I highly recommend if you get the chance), but since you asked... I ended up getting a Porsche Cayman S back in 2013, and I got into track driving.

CaAiRV8.jpg


After a while, I decided I wanted to try racing, and did a couple endurance races with a super low budget team racing an early 90's Subaru Impreza. Here's me finishing a 12 hour enduro in second place in my class:

kbsj58A.jpg


Recently, I decided I didn't like the cost of maintaining/insuring/registering multiple cars, so I sold the Porsche and my old Outback and got a Subaru STI, which I still have today. I've had it out on the racetrack once already, and I'm working on getting it more track ready for this summer. We'll see where that goes though, because this is a hobby that makes L3 rocketry look cheap by comparison...
 
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:facepalm: Oh good grief. All of this stuff is public domain. Not ITAR, not classified in any way.

I only provide FinSim, HyperCFD, etc free to U.S. citizens. Thats just the way it has to be. But, I enjoyed the conversation even though I am a little late with this response. Please see the following link for the FinSim distribution statement. https://www.aerorocket.com/products/products.html. Thanks. John Cipolla
 
I only provide FinSim, HyperCFD, etc free to U.S. citizens. Thats just the way it has to be. But, I enjoyed the conversation even though I am a little late with this response. Please see the following link for the FinSim distribution statement. https://www.aerorocket.com/products/products.html. Thanks. John Cipolla

My comment was more of a general commentary on the information that we as hobbyists have access to freely on the internet. I don't fault you in any way for limiting the distribution of your product, as I'm sure you have good reason and right to do so. I'm just thrilled that it's free! (and that I don't have to try and work out the math in spreadsheets)
 
My comment was more of a general commentary on the information that we as hobbyists have access to freely on the internet. I don't fault you in any way for limiting the distribution of your product, as I'm sure you have good reason and right to do so. I'm just thrilled that it's free! (and that I don't have to try and work out the math in spreadsheets)
AeroAggie, I appreciate your comments and was only providing a little information. Thank you.
 
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