V2 Stability

Team Gardei plans to launch a LOC 5.38 V2 (built by Ryan S.) with a AMW J500 (Provided by n3tjm) at the July 19th CMASS rocket launch. Without the motor, the CG is right in the middle. When loaded with a J500, it shifts about 5" forward of where the tail cone begins. I tried loading the specs of the V2 in Rocksim, but I don't trust the results... Rocksim shows the CG located in the TIP of the nosecone. According to Ryan, the V2 weighs approx 7lbs, 3lb is the nose cone. What do you thing guys... do you think Ryan's V2 will be stable with this 180 lb thurst motor? Can someone sim the CG/CP relations for me?

Doug,

Here are some measurements from Rsims on EMRR.

Apogee Micro V2 - 7" long, RsimCP=4.936, Barrowman CP=4.347, Rsim CP distance from nose is 70% of its length, Barrowman is 62%

LOC 4" V2 - 34" long, RsimCP=23.932, Barrowman CP=18.597, Rsim CP distance from nose is 70% of its length, Barrowman is 54%

LOC 5.5" V2 - 47.77" long, RsimCP=34.202, Barrowman CP=27.215, Rsim CP distance from nose is 72% of its length, Barrowman is 57%

You probablu should pop over to EMRR and take a look yourself.

When you use the mass override function, the CG stays at the nose tip. I never use the CG fro Rockesim. I just use it to figure out the CP then I find out where it is on the actual rocket. Then I go from there.

you can safely say that the CP will be from where the front edge of the fin meets the body tube to mabey an inch forward of that point on the 5.3 dia model..depending on the fin span ..I've drawn up alot of V-2's lately and thats where the cp always ends up for me..sound like your on the very edge of safe stability with out further noseweight

The CG of mine is approx. 6in from the top of the fins. With the motor it will obviously move backwards.

The V2 is almost done being painted. It just needs the top silver stripe (it is being painted the yelow and black check version)

thats perfect ..let it rip!

don't forget,,pics please..V-2's are probably my favorite!

V2 Info from someone who knows

Contact William Beggs jr.

https://ouray.cudenver.edu/~wrbeggs/newindex.html

That guy knows plenty about V2 Rockets. In fact, he is a veritable warehouse of information pertaining to that particular rocket.

ryan

I misread your post thinking WITH motor in it

That may not be stable ....whoops

O, you got me all exited.

I don't think the CG would move that far back with the motor. Maybe an inch, but then this might be enough to effect the flight

What is the weight difference between the I357 and J500?...I dont think it could be that much.

It is more than twice that of the I357... If I remember correctly, the CG with a dry loaded J500 was 5" above the tailcone (or was that fins?). I assume you had the recovery system and everything inside the rocket?

Yes Everything was inside the rocket. I am not sure which it was if this helps though the tops of the fins are about 1.5" about the top of the tailcone

Ok... I may be thinking about the fins then... We will balance it again Saturday. Will 4 - 5" abouve the fins be stable?

5" above the fins should be safe... Andy Woerner (V2 king) told me that the CP of a V2 is right around the top of the fins, so as long as you're a caliber ahead of that, you should be OK. Besides, it's a J500... it'll move so fast stability won't be an issue