Wildman's MACH 2 rocket

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It might be worth checking whether one of the components has an override of weight or cg?


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The CG is overridden at the top level (Stage) of the BOM. Need to change that manually if you've already built the rocket, or undo the override if you want OR to estimate the CG for you.
 
I just checked that file from post 12...um it's wonky..only 3 fins way oversize and stability off the chart -3.06
Nose cone wrong. Not 4-1 [9in] should be 5-1 haack [13.25in]

Good catch - I had uploaded the old .rkt I used as a starting point, while making all the updates in .ork
Just exported out the clean version into .rkt, and updated the original post with the clean .rkt as well as .ork

Somehow, saving-as .rkt changes some values (fin tab length gets needlessly elongated, fin fillets material gets reset to cardboard, etc). I fixed a few that I found, may have missed a few.


Mine built, no gear installed weighs 4lb 10oz.
I'll just do another new file.

Mine comes out at 1304g, or almost 3lb.

a
 
I got mine yesterday, stashed inside of the long skinny box carrying the airframe of a Falcon 3. Sweet!

Also sweet is that the fins on mine are beveled on both leading and trailing edges. The bevels aren't as steep as CJ's hand-bedazzled ones, but they still look pretty nice. Bevels on the trailing edges are essential -- they make your ballistic recoveries look pro when the only thing above ground is the those trailing edges and maybe a motor retainer.
 
I forgot to mention, mine weighed a bit heavier due to it's the sustainer and has 38mm motor mount and all the stuff that goes with it.Most will just be minimum diameter and weigh less.
 
Also enclosed is a .rkt and .ork files I build based on the actual dimensions (slightly different then those listed on WM site).

On AT L1000, it sims out to 19K feet and 2,472 fps (Mach 2.2).

a

There are still some things not quite right in the updated sim file you posted. You were using the trapezoidal fin shape tool, which I find is a pain in the butt. I converted yours to freeform and compared the measurement points to what I have taken off of the actual fins. The fin is not as tall or as long as what you have in the file.

Yours:
Afadeev Fin Mach 2.png

Mine:
Freeform Fin Mach 2.png

A few other things:

The fin material is 1/8" G10, but is shown as 1/4" in your sim file. Your file also has fin tabs--doesn't hurt anything unless you are trying to estimate the weight, but looks funky. [EDIT - maybe that was scrubbing the altitude from your sim.]

Your sim doesn't include the switch band. The rocket can be built with/without it. On my model I included the switch band (a 1"piece of body tube), and the coupler is indented under that.


One final thing that I'm not really sure about. You are showing the NC as 13.25" overall, which is correct. But the taper in the sim starts from the base of the NC. It appears to me that the NC actually has 2" of straight sides at the base, then starts to taper. To simulate this in my file, I made the NC 11.25" and added a piece of body tube to the BOM to model the straight side walls.

Here's my sim with the changes noted above:
View attachment Wildman Mach 2 (RHK 2018-02-10).ork

I have not added any of the internal components (bulkheads, electronics, recovery hardware & equipment, etc.). I don't care about the OR weight and CG estimates, I'll just measure the actuals when it's built and add them as overrides.
 
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Dan Man Walking - the attachments does not seem to be valid. Could you try again?
 
Dan Man Walking - the attachments does not seem to be valid. Could you try again?

That's happened to me lately, post all pics the same using manage attachments, occasionally they show up like that. For awhile you could click on them & open in a new tab/window....then after a week or so become invalid.

https://www.rocketryforum.com/showt...-MC-Nike-Apache-2-stage&p=1760460#post1760460

https://www.rocketryforum.com/showt...-MC-Nike-Apache-2-stage&p=1759415#post1759415

What seems really strange is on same post 3 pics show up and 2 say [ attachment 3344555] where pic should be.
I tried several times...re-sized pics [made no difference] to post...kept coming back {attachment} gave up. They worked as links for a week or two then stopped functioning. I deleted the problem out of my posts. Seems to be a "rogue" issue.
 
I reposted the links. It looks like the .ORK file link was working so I didn't mess with it. I am having some of the same problems Jim describes. When I preview the post (during edit) it displays images. When I first put the post up (or the edit up), it still shows images in my browser. But later, I saw that the post was showing a link to the images (but still brought up the images). And even later, that link was broken.

The fin shapes are in the .ORK files, which are working. so if this breaks again I'll cry uncle on this.
 
Issues like this are why I always store photos or files on another service and then embed or link them in a post. Google photos works great for this purpose and is much more reliable and persistent than here. I'd stay away from flickr though as it seems those embedded images die over time as well. For files I use Google drive. It's incredibly simple.
 
ORK says... (this is not 100% accurate file)

20,675' @ 1502 mph (M2.01) with a L1000W
20,660' @ 1029 mph (M1.40) with a K250W
19,056' @ 1421 mph (M1.90) with a K1050W
16,189' @ 1226 mph (M1.64) with a K858FJ
12.148' @ 1003 mph (M1.34) with a K695R
10,656' @ 1004 mph (M1.33) with a J1999N

looks like fun on the single grain 54mm too

Just ordered one....
 
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Well ORK is wrong they were flown on the L1000 to just under Mach 3


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:eyepop: Holy fiery nose cones Batman
mic-drop.jpg
 
Well ORK is wrong they were flown on the L1000 to just under Mach 3
Sent from my iPhone using Rocketry Forum

According to what?

If it is a barometric altimeter, forget it. If accelerometer, then still questionable. Simulations are the best predictor of top speed.
 
ORK says... (this is not 100% accurate file)

20,675' @ 1502 mph (M2.01) with a L1000W
20,660' @ 1029 mph (M1.40) with a K250W
19,056' @ 1421 mph (M1.90) with a K1050W
16,189' @ 1226 mph (M1.64) with a K858FJ
12.148' @ 1003 mph (M1.34) with a K695R
10,656' @ 1004 mph (M1.33) with a J1999N

looks like fun on the single grain 54mm too

Just ordered one....

Why did you stop there?

23,896 @ 1579 mph (M2.13) with a L935 CTI 6XL Imax

I used the sim file I posted, with a weight override for 64 ounces. This sim is as wrong as the others based on Tim's post. Just more bigger wrong.
 
According to what?

If it is a barometric altimeter, forget it. If accelerometer, then still questionable. Simulations are the best predictor of top speed.

:facepalm:

Too many variables to record and input from the field (temperature and humidity at ground level... at 1 mile... at 2 mile... at 3 mile... at 4 mile...).

Simulations are intended to give you an idea of what to expect. Nothing replaces experience and results as documented.

Im waiting for someone to shove a Loki L1040 in one of these bad boys...
 
:facepalm:

Too many variables to record and input from the field (temperature and humidity at ground level... at 1 mile... at 2 mile... at 3 mile... at 4 mile...).

Simulations are intended to give you an idea of what to expect. Nothing replaces experience and results as documented.

Im waiting for someone to shove a Loki L1040 in one of these bad boys...

Top speed usually occurs within a few seconds and couple thousand feet from liftoff, so no need to worry about humidity at 4 miles. At least simulations account for ambient temperature corrections to the atmospheric model. Some (most?, all?) barometric altimeters do not. :facepalm:

Not sure what "results as documented" means. If you are referring to flight measurements, then have a look at all the threads in this forum with nonsensical data from hobby altimeters - especially top speed. A good computer model is the benchmark for velocity determination. Simulations count as "experience", too.
 
Top speed usually occurs within a few seconds and couple thousand feet from liftoff, so no need to worry about humidity at 4 miles. At least simulations account for ambient temperature corrections to the atmospheric model. Some (most?, all?) barometric altimeters do not. :facepalm:

Not sure what "results as documented" means. If you are referring to flight measurements, then have a look at all the threads in this forum with nonsensical data from hobby altimeters - especially top speed. A good computer model is the benchmark for velocity determination. Simulations count as "experience", too.
Oh hell yeah... I just ordered 2 of these things, and use one for an L935, and another for a Loki M motor, which I'll have to extend the body of the rocket.



Ben
 
Just recieved my Mach2 in mail today and it has both leading and trailing edges tapered. Will only need light touch up sanding. This is by far the highest performance rocket I have. Came with small batch of epoxy and fin guides. Nice machined fiberglass e-bay bulkheads.

Nice kit. Glad I got one.
 
A random data point for those still following this thread: On a CTI J210 (2-grain Classic) mine reached 9274' with max velocity of 1191 fps at Black Rock last August. Altimeter was a TRS. It came off the rail at a bit of an angle which scrubbed some altitude. I had an L1000 ready to go for a follow-up flight but never got the chance, strong winds closed things down for the rest of the day
 
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