Wildman V2 Sport (BUild Thread) (Directions Preview)

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Instructions for bending the retaining rings: Grab ring at 0.2" (5mm) from end with linesman's pliers and bend inward 90 degrees. Repeat for the other end. The end result should look like this:

29mm_retainer_ring.jpg

Jeroen
 
Instructions for bending the retaining rings: Grab ring at 0.2" (5mm) from end with linesman's pliers and bend inward 90 degrees. Repeat for the other end. The end result should look like this:

View attachment 246942

Jeroen

caveman-creations.jpeg
 
Are the rest of us going to be able to buy one or two? I'm not seeing these on the site?
 
boat tails are easy...they are simply transitions, fins on boat tails is the hard part. don't know of a work around that will allow an accurate flight simulation.
Rex
 
boat tails are easy...they are simply transitions, fins on boat tails is the hard part. don't know of a work around that will allow an accurate flight simulation.
Rex

So what's the best way to pick a motor for any V2, thrust to weight ratio? I'm building the 4" V2 and sims are all crap
 
Really happy to find this build thread. I'm one of those lucky soles that threw money at Tim to get my hands on one of these bad boys.

Has anyone generated a Rocksim file for this rocket yet?

What length and size shock cord did you use in the build? How did you affix the shock cord to the nose cone?

Any recommendations on the parachute?

Finally, is there any reason to not construct this in the ziperless style? I recognize that would mean moving the rail buttons forward, which would seem to be a good thing in terms of moving a small amount of weight forward. Did you have to add any nose weight?
 
Really happy to find this build thread. I'm one of those lucky soles that threw money at Tim to get my hands on one of these bad boys.

Has anyone generated a Rocksim file for this rocket yet?

What length and size shock cord did you use in the build? How did you affix the shock cord to the nose cone?

Any recommendations on the parachute?

Finally, is there any reason to not construct this in the ziperless style? I recognize that would mean moving the rail buttons forward, which would seem to be a good thing in terms of moving a small amount of weight forward. Did you have to add any nose weight?
Not sure about a rock sim file. I used about 10 feet of 1/4" Kevlar shock cord. Tie a knot in one end and sink that end into the tip of the cone. Then fill the tip of the cone with epoxy enough to cover the knot. For a chute, I would stick with a 12-15"

zipperless? Knock yourself out. I think it would work just fine. Nose weight....none, just a tracker and recovery gear. Good luck, post pictures.
 
I've got an OpenRocket file, but it's pretty useless. The CP/CG is way off. Something to do with the fact that OR doesn't calculate boat-tails well. If you still want it, lemme know.
 
I've got an OpenRocket file, but it's pretty useless. The CP/CG is way off. Something to do with the fact that OR doesn't calculate boat-tails well. If you still want it, lemme know.

It is the Barrowman Equations that are at fault. Essentially it assumes the fins are attached to the major body diameter, which negates a fair amount of the fin area. Rocksim has the Rocksim method, which alters/extends Barrowman and this is one of the areas it improves upon. I think it takes the fin span at mid-tail cone, which would improve the cp calculation.
 
boat tails are easy...they are simply transitions, fins on boat tails is the hard part. don't know of a work around that will allow an accurate flight simulation.
Rex

The workaround is to use RockSim and not waste your time with open rocket.
 
I found a crappy file on the web for the Estes V2 (#1926) that needed a lot of corrections, which I did in OR. It's not perfect, but much better than what I started with. The simulation shows apogee at 1420' on an AT F24-7 and my Altimeter2 recorded actual apogee at 1398'. That's about a 1.5% discrepancy. How close is close enough?

Dennis
 
I found a crappy file on the web for the Estes V2 (#1926) that needed a lot of corrections, which I did in OR. It's not perfect, but much better than what I started with. The simulation shows apogee at 1420' on an AT F24-7 and my Altimeter2 recorded actual apogee at 1398'. That's about a 1.5% discrepancy. How close is close enough?

Dennis

That's pretty good. My sims with OR are not even close to reality. Would you mind sharing that OR file?
 
Tim,

No problem. Here is the file. If anyone knows of anything that I could have done differently, please let me know. I am open to any suggestions to improve my OR

Thanks,
Dennis

Thanks!
What I noticed is that when you take your file & convert components to fiberglass, the rocket becomes unstable.
 
I have not done any V2 conversions to fiberglass yet. However, I would expect it to go unstable. It surprised me when I read on this forum that the Wildman kits did not require any added weight to the nose, especially when you look at how much I had to add to the Estes kit. Maybe the NCs are just that much heavier.

Also note that the fins are larger to scale on mine.

Dennis
 
Mr Man - have you actually compared any real flight data to Rocksim simulations with boat tail rockets & if so, how did it compare?

Tim, I did recently design, build and fly a rocket with a large curved boat tail, similar to the V2 but with some highly swept retro style fins. I did not have any on board electronics to record flight data, but RockSim did accurately predict stability, the correct motor delay, and to my eye a pretty good estimate of max altitude. So no, I can't claim any altimeter-based confirmation, but my flight was a success because of the accurate guidance that RockSim provided in terms of stability and motor delay. RockSim predicted a max altitude of 690 feet, and to my eye the altitude was closer to 600 feet, but that is obviously a guess and not real data. But it seems to me things like stability and proper ejection delay (when using motor ejection) are more important things to get right than max altitude. When was the last time a flight failed because the rocket flew to 1200 feet and the sim said it would be 1000 feet?

My point here is that even if RockSim's altitude numbers are not 100% accurate with things like boat tails, fin pods, asymmetrical fins, ring fins etc., it does allow you to design and simulate these types of rockets and Open Rocket does not. Over a series of simulations and flights with altimeters, you can get a feel for which way it is off and by how much, and that is enough for me. Because I find basic '3 fin and nosecone' rockets really, really boring, I like to design and scratch build unique rockets with these types of features, and so Open Rocket was never an option for me. I can see that with a different set of priorities, say maximum performance, or minimum diameter, etc, OR would be a viable choice.
 
I guess it wasn't so much an altitude thing more so than would it fly. OR sims I have found are generally crap with boat tails. I know my V2s will fly with proper thrust to weight ratio, but I like to experiment with sims when choosing motors which is why I was asking about rocksim. Thanks!
 
Griffin,

Did you shorten the MMT to be just above the centering ring? If I place the motor retainer flush with the boat tail, I have about an 1.25" above where the CR will sit. pictures above look like your MMT was maybe .25" above.
 
I didn't shorten the motor tube. I wouldn't be surprised if the motor tube lengths are a bit different from the prototype. If you want to cut off the extra, it won't hurt anything.
 
I flew my V2 sport yesterday for the first time, F44-4, no nose weight - a little wobble off the pad but a nice flight, maybe 800-1000'. Next time it gets a bigger motor!
 
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