Is there a way to find the CP without doing the cardboard cutout test?

I'd like to learn how to find the CP of my rockets (I'm only up to level 1 kits so far). I read in Harry Stine's Handbook of Model Rocketry about the cardboard cutout test. I was wondering if there was another method - say, for a finished rocket.

The cutout test seems like a nice, easy way to do it, but I'm not sure how to trace an exact outline of a finished rocket. Also, a question: does the cutout test work equally well for a three-finned rocket as for a four-finned rocket? I ask, because with four fins, if you look at it from either the tip of a fin on, or from the center between fins, with a four-fin, you have bilateral symmetry either way. But you don't have bilateral symmetry if you look at a three-fin from, say, the side of one fin. I'm just curious if that's a problem.

Thanks for your help!

Open Rocket

Use Modified Barrowman equations. Try this site. https://my.execpc.com/~culp/rockets/Barrowman.html

As mentioned - simulation software or Barrowman equations are the only other 2 ways I know.

And, they can give you a bit more flexibility in design, since the cardboard cutout method is sort of a "worst case" method, that is, it assumes the rocket is 90 deg to the airflow (which, hopefully, it never will be).

Bat-mite said:

Use Modified Barrowman equations. Try this site. https://my.execpc.com/~culp/rockets/Barrowman.html

Click to expand...

Thanks for that! That beats the Heck out of OR anyday. OR just PI$$e$ me off most of the Time. I like Rocksim but can't afford it.
I saved this Link to my Favorites List.

ETA: After looking it over, and realizing that Math is'nt my thing, I'll stick to Mindsim.

Cosermann said:

As mentioned - simulation software or Barrowman equations are the only other 2 ways I know.

And, they can give you a bit more flexibility in design, since the cardboard cutout method is sort of a "worst case" method, that is, it assumes the rocket is 90 deg to the airflow (which, hopefully, it never will be).

Click to expand...

Dont you want the rocket 90 degrees to the airflow

g zilla said:

Dont you want the rocket 90 degrees to the airflow

Click to expand...

No. Typically you are only dealing with small angles of attack, in which the fins are not stalled.


Sent from my iPhone using Rocketry Forum

SWING TEST of finished model. Super easy to do. Should be in The Handbook of Model Rocketry. I trust the swing test more than any of the rocket software available.

DanFrank said:

SWING TEST of finished model. Super easy to do. Should be in The Handbook of Model Rocketry. I trust the swing test more than any of the rocket software available.

Click to expand...

I did a swing test of a modified Fat Boy once years ago looked good, flew like crap, and you can't swing test the big ones.

Swing test tells you if you are stable, but doesn't give you a CP measurement.

DanFrank said:

SWING TEST of finished model. Super easy to do. Should be in The Handbook of Model Rocketry. I trust the swing test more than any of the rocket software available.

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This^^ X1000
Always worked for me too.
Sims confuse me, but since 1992-93 I've been able to make Rockets with more than one set of Fins fly just fine.
That's way before the Internet and Sims in my Book.
I did'nt learn Internet til' I was in the Army in 02'.
I'de already done 5 successful Launches of a Scratch Build that rode G40s and 80s nicely before meeting a Tree, which is now Dead.:tongue:

I can whip up a crude model in Open Rocket in about 3 minutes, unless very unusual. Doesn't have to be perfect. You can even find out the cardboard cutout CP by checking it at 90 degree angle of attack. On more unusual designs, no substitute for wind testing (which I find preferable to swing testing).

Most rockets that are fairly standard 3-4 fin rockets I had a good fell for from experience and kits I built over the years. Fiberglass and stubby rockets changed that a bit and got me to use OpenRocket. If I can't find a file online, I just do the external parts to get the CP. If I want to sim a flight, I weigh the rocket empty and override it. Seemed like the path of least resistance for me.

lcorinth said:

I'd like to learn how to find the CP of my rockets (I'm only up to level 1 kits so far). I read in Harry Stine's Handbook of Model Rocketry about the cardboard cutout test. I was wondering if there was another method - say, for a finished rocket.

The cutout test seems like a nice, easy way to do it, but I'm not sure how to trace an exact outline of a finished rocket. Also, a question: does the cutout test work equally well for a three-finned rocket as for a four-finned rocket? I ask, because with four fins, if you look at it from either the tip of a fin on, or from the center between fins, with a four-fin, you have bilateral symmetry either way. But you don't have bilateral symmetry if you look at a three-fin from, say, the side of one fin. I'm just curious if that's a problem.

Thanks for your help!

Click to expand...

The "cardboard cutout method" is basically the most conservative method of determining CP, which is to say, it locates the CP in the worst case scenario, with the rocket turned 90 degrees to the direction of flight (90 degree angle of attack). CP is not a static location point on the rocket, but moves around depending on the speed, air density, and angle of attack of the rocket to the air slipstream it's flying through. The further the nose is off the direction of flight (greater the angle of attack), the further forward the CP moves... It moves the furthest forward when the angle of attack is 90 degrees to the direction of flight. Basically, the cardboard cutout method is more correctly termed "the center of lateral area". The best way of doing it is to make a scale drawing of the rocket on paper or cardboard, and then trace it onto cardboard, and cut it out. You're right that you really can't trace the rocket itself with any accuracy. Doing a scale drawing of the rocket's outline isn't particularly hard though. Balance the cutout on a ruler, and you've found the center of lateral area... which is the CP point in the worst case scenario. In actual conditions, the CP is actually further back, meaning that if you balance the rocket (add noseweight) or increase the fin size to make it one-caliber (one body diameter) stable using the cardboard cutout method, it will actually be MORE stable than indicated, as the REAL CP in dynamic flight will be further back than indicated by the center of lateral area. This can be a good or bad thing, depending on conditions (like flying in wind, where the more rearward actual CP will cause excessive weathercocking...)

There's the good old Barrowman equations to calculate stability, but it's a chore unless you're a math whiz and enjoy that sort of thing. Plus, they make some basic assumptions that hold up for a lot of situations, but break down in others. Additionally, they can only analyze rather simple shapes.

Then there's the various rocket simulator programs... RockSim and Open Rocket... they can calculate CP directly on the computer... of course, the different methods give slightly different results. Rocksim has three methods to calculate CP, which one can choose from the menu... You can set it to "cardboard cutout method" where it simply calculates the center of lateral area mathematically in the computer, essentially a digital version of the cardboard cutout method, or you can choose the Barrowman Method and it will do the calculations for you. You can also set it to the "Rocksim Method" which uses updated algorithms and methods to calculate it, using basically "tweaks" and different "assumptions" than the traditional Barrowman method... That's why the results are slightly different. I don't have experience with Open Rocket, but I assume it has a similar methodology...

Anyway, that's pretty much your choices... if you want to find the "actual" CP, you can do a string test... balance the rocket in a string loop horizontally so it's even (at the CG). Swing the rocket, and it should "fly" in a circle nose first. Now, gradually move the string back and repeat, until the rocket will no longer turn "into the wind" as you swing it... that should be the APPROXIMATE CP, since the air forces working on the rocket on one side of the string is equaled by the air forces working against the fins and surface area on the other side of the string (assuming you've added weight to the aft end as you moved the string back to negate the shift in CG from moving the string behind the ACTUAL CG). Course this is a complicated process itself, and only gives an approximation-- the CP is a dynamic "point" and moves around in flight depending on the previously mentioned influences...

Later and good luck!

OL JR

Great thread so far. Thought I'd add this newsletter article to the mix.

https://www.apogeerockets.com/downloads/Newsletter53.pdf

(Full disclosure - keep in mind it's written by someone who also sells simulation software).

rcktnut said:

I did a swing test of a modified Fat Boy once years ago looked good, flew like crap,

Click to expand...

With internally modified (more motor mounts, etc) known rockets, test fit it together "stock" and mark with a Sharpie where the CG is, then modify away. After your creation is built, add nose weight to keep the CG at the same location.

rcktnut said:

and you can't swing test the big ones.

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Sure you can! Just use more string and a stronger arm...

DanFrank said:

With internally modified (more motor mounts, etc) known rockets, test fit it together "stock" and mark with a Sharpie where the CG is, then modify away. After your creation is built, add nose weight to keep the CG at the same location.
)

Click to expand...

This sounds logical but I am not sure it is altogether correct. Specifically if your modifications result in either a heavier or draggier rocket, your velocity from ignition to release from launch rod or rail is going to be lower (unless you change motor to increase thrust.). At a lower velocity, your fins are not as effective and therefore your EFFECTIVE Center of Pressure moves FORWARD (bad.)

Think an intrinsically stable rocket, like a Big Bertha. Add some nose weight. Should make it more stable (or what might be called "over stable."). All true at first. But at a certain point, should you keep adding nose weight, and assuming you don't adjust for that with a more powerful engine (and thus more tail weight) you can add so much weight that Bertha is barely getting off the pad. Without sufficient velocity, doesn't matter how much nose weight you have, it ain't gonna fly straight. With all due respect to DaddyIsABar (who certainly pulls off some amazing stuff). there are some things that nose weight (alone) can't fix.

That being said, if your modifications move the CG back, you probably are heading in the direction of a LESS stable rocket.

So adding nose weight to bring CG back to baseline post modification certainly is a start, but doesn't guarantee rocket will still be stable if mass and/or drag are increased WITHOUT a corresponding increase in thrust.

TopRamen said:

Thanks for that! That beats the Heck out of OR anyday. OR just PI$$e$ me off most of the Time. I like Rocksim but can't afford it.
I saved this Link to my Favorites List.

Click to expand...

Geez, I bought RockSim 6 years ago and I still use it all the time. It was invaluable when I was designing my scratch-built Level 1 rocket and planning for my cert. flight. It's price is equivalent to a nice kit or a few reloads, certainly within the reach of almost everyone here. I guarantee that I am poorer than you and yet I scraped up the money for it, and I'm glad I did. In the time I've had it RS has cost me less than $20 per year. Another way of looking at it is that the price is equivalent to spending $10 per month for one year. You probably spend more than that each month just for coffee on your way to work.

What I'm saying here is that a decent sim program like RockSim is a good investment if you want to be able to find answers to these sorts of questions. And if you are serious about this hobby, you'll want to have the tools that will enable you to answer them.

One thing maybe of interest is you can do the cardboard cutout as a calculation without actually cutting out any cardboard. I did this for my first 2 rockets as a BAR; since they were unusual designs I figured this would actually be quite accurate, and wind testing and flight proved this correct. The first had 12 overlapping fins so the shadow or profile wouldn't actually show everything, although one could stack up pieces of cardboard for various parts.... The calculation is similar to hand working the Barrowman equations, except simpler. First the "moments" of the various pieces are added together, area times distance from the nose. Then this divided by the total area.

For example, a 3 fin rocket with a conical NC, sample values pulled out of the air:
NC 6" L x 1" dia. conical, area = 3 in.^2, CP at 4" (2/3 L), moment = 12 (in.^3)
Tube 10"x 1" starting at 6", area = 10, CP position 11", moment = 110
Fins 2"x2" square at back of tube, worst case one edge-on and 2 at 30 degree view = 8 x cos(30) = area 6.93, CP pos. 15", moment 103.92.
Total moments = 216.92
Total areas = 19.93
CP = 216.92/19.93 = 10.884"

With my Santa Express, the calculation is even simpler. The long conical nose cone, body and low profile fins form almost a triangle 33" long. CP for a triangle would be at 2/3 L = 22". Since the 4 fins are slightly wider in flat-on-to-2 view, or doubled at 45 degree view, it's more stable than that, so CG can be at 22".

MarkII said:

Geez, I bought RockSim 6 years ago and I still use it all the time. It was invaluable when I was designing my scratch-built Level 1 rocket and planning for my cert. flight. It's price is equivalent to a nice kit or a few reloads, certainly within the reach of almost everyone here. I guarantee that I am poorer than you and yet I scraped up the money for it, and I'm glad I did. In the time I've had it RS has cost me less than $20 per year. Another way of looking at it is that the price is equivalent to spending $10 per month for one year. You probably spend more than that each month just for coffee on your way to work.

What I'm saying here is that a decent sim program like RockSim is a good investment if you want to be able to find answers to these sorts of questions. And if you are serious about this hobby, you'll want to have the tools that will enable you to answer them.

Click to expand...

Well lets see, I only drink $7 worth of Instant Coffee per Month, and am a Disabled Veteran, so don't be so quick to think I make the Big Bucks.
Aside from that, Next year will will be the 30th aniversary of my introduction to the Hobby, and I've been Scratch Building since around 89'.
Granted, life has lead me down other Paths from time to time, so I have'nt been consistently building Rockets the whole time, but my Mindsim and Common Sense has yet to let me down when it comes to simple things like CG/CP and balancing things.
As for the Barrowman Equations, I tried to play with them and then remembered why I despise Math.

TopRamen said:

Well lets see, I only drink $7 worth of Instant Coffee per Month, and am a Disabled Veteran, so don't be so quick to think I make the Big Bucks.
Aside from that, Next year will will be the 30th aniversary of my introduction to the Hobby, and I've been Scratch Building since around 89'.
Granted, life has lead me down other Paths from time to time, so I have'nt been consistently building Rockets the whole time, but my Mindsim and Common Sense has yet to let me down when it comes to simple things like CG/CP and balancing things.
As for the Barrowman Equations, I tried to play with them and then remembered why I despise Math.

Click to expand...

Well, There's always "Open Rocket"... you can download it off the net for free...

I agree that I used the TLAR method for many years without failure... "That Looks About Right"... Tried the Barrowman equations myself and I agree with you... I remember why I hate math... LOL

Later! OL JR

luke strawwalker said:

Well, There's always "Open Rocket"... you can download it off the net for free...

I agree that I used the TLAR method for many years without failure... "That Looks About Right"... Tried the Barrowman equations myself and I agree with you... I remember why I hate math... LOL

Later! OL JR

Click to expand...

I admit, I do have OR, and occasionally use it, but here's why I don't like it.
On my latest Build, a TLP TAN-SAM, I started with the Nose Cone, no problems there. BT-80, No Problem there either. Upon selecting a 2.6" Diameter Centering Ring however, the Ring stuck outside of the Body Tube by twice its Diameter. How can the Centering Ring be twice the width of the same size Body Tube?
Stuff like that frustrates me.

TopRamen said:

I admit, I do have OR, and occasionally use it, but here's why I don't like it.
On my latest Build, a TLP TAN-SAM, I started with the Nose Cone, no problems there. BT-80, No Problem there either. Upon selecting a 2.6" Diameter Centering Ring however, the Ring stuck outside of the Body Tube by twice its Diameter. How can the Centering Ring be twice the width of the same size Body Tube?
Stuff like that frustrates me.

Click to expand...

Putting the outer diameter as the inner diameter?? I dunno, but that's where I'd start...

I have RS 8... I originally installed it on my old Dell computer that had a hard drive meltdown a couple years ago. It was getting very wonky anyway and would barely work. Had problems installing it originally on the machine, then the program messed up and wouldn't work at all, and I couldn't reinstall it. TVM was at times helpful and unhelpful and usually had some snarky comment to make during the process... The original disk that I got from Apogee somehow delaminated (reflective coating came off the back of the CD-ROM in a few spots-- NEVER seen that before!) and they DID send me a new disk, and a new activation code for it that I put on disk... Still, after a few months it became unstable and wouldn't work right... When the computer quit, I just gave up on it. Due to the problems I had and the spotty record of support from Apogee led me to not upgrade to RS9 when it came out... they already had $100 bucks of my money and I had a wonky, unstable program that sometimes worked and sometimes didn't... didn't see giving them more...

Due to a project I'm currently working on, I needed RS to check stability and do some simulations... I got RS8 installed yesterday on my "new" (over a year old) Gateway laptop... So far, so good, but it's too early to tell. I tried to upload the designs I'd done before that were stored on disks, (CD-ROMS) but it didn't work. Now the computer can't seem to find them on the disks... Oh well...

It's friggin' computers... if they ever invent one that'll work right, they'll really have something...

Later! OL JR

You can tweak the size, shape, surface and mass of anything in Open Rocket. You just have to play with it for awhile until things start to click.

The easiest way to learn, IMO, is to download a finished model from a web site (like Rocket Reviews) (also, OR can import Rocksim files). Look at what the modeler did. Examine each component. Compare two nose cones and see what makes them different.

But bottom line for CP comes down to area, not mass. So if you can even rudimentarily draw a rocket that has your outer dimensions, you can get the CP. Then build it and fid the CG by balance-testing it.

Bat-mite said:

You can tweak the size, shape, surface and mass of anything in Open Rocket. You just have to play with it for awhile until things start to click.

The easiest way to learn, IMO, is to download a finished model from a web site (like Rocket Reviews) (also, OR can import Rocksim files). Look at what the modeler did. Examine each component. Compare two nose cones and see what makes them different.

But bottom line for CP comes down to area, not mass. So if you can even rudimentarily draw a rocket that has your outer dimensions, you can get the CP. Then build it and fid the CG by balance-testing it.

Click to expand...

Quite true... CP is all about AREA, more specifically, "wetted area" or the area that is directly exposed to the slipstream of air moving past the rocket (or more properly, that the rocket is moving through). Of course this changes with angle of attack, wind (which puts the mass of air in motion, sometimes differential motion as winds aloft are from different directions than wind at the surface), etc.

If you can find your rocket design online anywhere, even at a different scale, the CP should be at an identical location proportionally as it would be on your rocket. For instance, doing an upscale or downscale should put the CP at the same point proportionally on the different size rocket as it is on the larger or smaller prototype. (This is actually a slight simplification, as Reynolds numbers and scaling effects for drastic changes in scale do come into play, but for MOST applications the theory is sound).

MASS only comes into the equation to relocate the CG point to a position far enough ahead of the CP to create a stable configuration for flight. Usually, adding noseweight to move the CG forward is the easiest and most straightforward method of trimming the stability of a rocket, rather than changing the outer mold line of the rocket (fin size, etc).

Later! OL JR

Another option is VCP, a simple graphical program that calculated the CP for you. I have used it on a few rockets with two sets of fins.

It's available here: https://v-serv.com/vcp/

Use a digital camera to take a side shot of your rocket and use that for your cutout.

MarkII said:

Geez, I bought RockSim 6 years ago and I still use it all the time. It was invaluable when I was designing my scratch-built Level 1 rocket and planning for my cert. flight. It's price is equivalent to a nice kit or a few reloads, certainly within the reach of almost everyone here. I guarantee that I am poorer than you and yet I scraped up the money for it, and I'm glad I did. In the time I've had it RS has cost me less than $20 per year. Another way of looking at it is that the price is equivalent to spending $10 per month for one year. You probably spend more than that each month just for coffee on your way to work.

What I'm saying here is that a decent sim program like RockSim is a good investment if you want to be able to find answers to these sorts of questions. And if you are serious about this hobby, you'll want to have the tools that will enable you to answer them.

Click to expand...

I am raising an old thread and hijacking it....

I agree entirely. The cost of Rocksim is relatively minor in the grand scheme of this hobby.

I think the problem is that people now expect all software free of charge, and so it looks unaffordable or is a "rip off" when they actually have to pay for it. (You can thank Napster for starting this trend). Gmail is free, iPhone apps are free, MS Office is free at work (for you, not your employer). After this kind of conditioning, well, rocket software should be free, too!

When somebody provides me a good or service, I usually expect to pay for it. I dabbled in software development and sales for a short time, and dammit, I expected to make some money from my efforts. I really don't understand the motivation behind freeware and open source. Yes, I do have my share of free apps and downloads. I just don't understand why developers are willing to do it!

Buckeye said:

Raising an old thread and hijacking it....

I agree entirely. The cost of Rocksim is relatively minor in the grand scheme of this hobby.

I think the problem is that people now expect all software free of charge, and so it looks unaffordable or is a "rip off" when they actually have to pay for it. (You can thank Napster for starting this trend). Gmail is free, iPhone apps are free, MS Office is free at work (for you, not your employer). After this kind of conditioning, well, rocket software should be free, too!

When somebody provides me a good or service, I usually expect to pay for it. I dabbled in software development and sales for a short time, and dammit, I expected to make some money from my efforts. I really don't understand the motivation behind freeware and open source. Yes, I do have my share of free apps and downloads. I just don't understand why developers are willing to do it!

Click to expand...

Yes, you're right... someone who develops something of use should be able to expect SOME type or kind of return... some do it for fun or for others (that's why we do hobbies like rocketry, or help TARC teams, or whatever), some do things for profit (sometimes a LOT of profit).

The question is, "Is it worth the money they're asking for it?" That is an individual decision. I bought Rocksim 8 about five or six months before RS9 came out. I loaded it onto my computer, had some issues, asked for advice from Tim Van Milligan at Apogee, after trying a few things, he suggested I uninstall it and reinstall it, finally got it working, after a exchanging probably a half dozen or so emails. At one point, Tim PO'd me pretty bad, when he actually wrote and told me, "Well, that's why you should have bought a MAC." I thought to myself, "Then WHY are you selling a program that's so unstable and full of bugs it won't run on a Windows machine, then?? If it's only stable on a Mac, then why not sell ONLY a Mac version of it??" Course I had the decorum not to tell him that... Then I had some other issues crop up and had to do it again a few months later... of course I had to get a new license file and burn it to disk, and I found my installation disk for the program, the original one I had received from Apogee, had delaminated or something, had a bubble on the surface like the reflective coating was peeling off, and the computer wouldn't read it. Apogee DID send me a new disk and license file free, I'll give them that. I found lots of things that were hard to do, didn't work quite right, and more than a few bugs... For the last 6 months I used it on our old computer, every time I would click the desktop icon to open the program, it would pop up some box with some updating database message or something and then close... click it again and it would finally open. I asked Tim about it in an email and he told me, "well, does it open?" "Yeah, on the second try, usually-- it never updates anything... just gives that message and apparently does nothing but abort on the first try"... "Well", says Tim, "if it opens eventually, don't worry about it." Basically the support was less than stellar, and the comments were uncalled for. When my old computer crashed, I didn't even bother reinstalling it on my "reworked" old computer we used until we could buy a newer laptop. I've had the laptop for a couple years and only reinstalled RS8 on it about a month or so ago for a project I'm working on.

I COULD have updated to RS9 for about $40 bucks extra when it came out. After having a lot of bugs and issues with RS8 for months already, with it working about half the time or so, I just didn't see the point in giving them MORE of my money... They already had about $100 bucks for the RS8. New versions are usually full of bugs, and RS9 had plenty of teething problems, and a lot of fixes, patches, and updates to correct it.

It's a decent program, don't get me wrong. It can do things we never even DREAMED of back in the mid-80's when I was in rocketry the first time... But is it worth the money?? That's an individual decision everyone out there contemplating buying it will have to decide for themselves.

I haven't used OpenRocket, the freeware equivalent of Rocksim, so I can't compare the two. I think a lot of it depends on what you're using it for. If I just wanted to be able to get a decent idea of where the CP was on a rocket, OR would probably do the trick, and save the $100 bucks (or whatever Rocksim is running now). You can do some simulations on OR, though whether they're as good as RS, I don't know...Dunno if OR is as buggy or problematic as RS was for me, or if other folks have experienced the same sort of bugs and problems with RS... I know SOME have, because there used to be a lot of discussion and questions about how to do this or that or how to make something work, or what to do to fix this or that...

I guess *I* just expected to get a product that would work reliably and not be buggy for my $100, and get friendly straightforward help when something went wrong, instead of snide comments from the vendor. I figured that not having gotten the first and gotten too much of the second, they didn't deserve another $40 bucks of my money, especially not to exchange one set of bugs for another...

Like I said, "let the buyer beware and MAKE UP THEIR OWN MIND". That's what happened to me. Hope you're luck has been/will be better!

Later! OL JR

TopRamen said:

I admit, I do have OR, and occasionally use it, but here's why I don't like it.
On my latest Build, a TLP TAN-SAM, I started with the Nose Cone, no problems there. BT-80, No Problem there either. Upon selecting a 2.6" Diameter Centering Ring however, the Ring stuck outside of the Body Tube by twice its Diameter. How can the Centering Ring be twice the width of the same size Body Tube?
Stuff like that frustrates me.

Click to expand...

So don't put in the centring rings or any other internal components. They won't affect the CP anyway. Model all the external components and use OR to find the CP; find out where the rocket balances on your finger or on a narrow edge, that's the CG; if the CG is far enough ahead of the CP then the rocket is stable. (You will, of course, have to enter all the internal components if you want OR or Rocksim to simulate the rocket's flight!)

But good luck getting OR, or for that matter Rocksim, to figure out the CP of something like these:


One is the old Estes Black Hawk - two parallel body tubes joined together by a tapered box which includes the internal plumbing to get the ejection gas from the aft central motor mount to the starboard nose. The other is my scratch-built Delta Gamma 9 with "docking clamps" on the nose, an angled shroud around the rear 1/3 of the body with a gap between it and the body, and a weird-shaped boat tail around the motor mount.

Sometimes all you can do is add enough nose weight until CG satisfies TLAR, swing test it so you can tell the RSO you did, then send it up and hope for the best...