The New Madcow Piranha

That's a nice looking kit. I might wait until the sale to pick up something new to collection I have, which isn't much.

If you read the instructions (online at the Madcow site or in the attachment you posted) Step 5 says you are responsible for insuring that the CG is at least one body diameter forward of the specified CP (19" when measured from the tip of the nosecone). Thereafter follow instructions for adding nose weight (lead shot or similar, epoxy, etc.) I think bamboo skewers would work just as well as a screw through the nose cone but we're adding nose weight so who cares?

The Squat rocket that everyone is eagerly awaiting*** requires the same CP/CG treatment. One needs only watch the video clips of the LDRS Squat drag race to see what happens when the CP/CG is ignored.

*** My Squat arrived a few days ago so I'm a happy owner rather than an anxious Black Friday shopper. On the other hand, I'm hoping to score a Frenzy. *sigh*

o1d_dude said:

*** My Squat arrived a few days ago so I'm a happy owner rather than an anxious Black Friday shopper. On the other hand, I'm hoping to score a Frenzy. *sigh*

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I have a Frenzy already (still in the box), what I'm hoping to get is a good price on the 4" AGM-33 Pike. Sweet looking kit.

neond7 said:

I have a Frenzy already (still in the box), what I'm hoping to get is a good price on the 4" AGM-33 Pike. Sweet looking kit.

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So between us we have everything we want? LOL!

I bought the 4" Frenzy during last years sale. I have flown it now three times and it's always a thrill. Hearing those fins whistle after burnout is something else.

I am hoping for the 54mm Tomach to be in his sale this year. I tried to download the RocSim file for it, but no luck.

Green Jello said:

Can someone play with the Rocksim file for me? No matter what I do with the nose weight, the CG won't move. What is wrong with this thing?

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Click on the "sustainer" in the components list. Unclick the "override mass" box.
That should work.

Alex

Boy, that is one jacked up RockSim file. Almost everything was overridden, the fins and centering rings showed zero weight, and there was no parachute or shock cord. Here is what I came up with. Adding 4oz of nose weight gives you stability of 1.23, with a G53FJ.

View attachment Madcow Piranha_OR.ork

I ordered one. Madcow is pretty quick at shipping I bet they will be on the way really soon

I received my ship notice last night. They are getting them out quickly.

Mine shipped yesterday too.

Just a FYI about nose weight - if the nosecone is the same material as the Squat, be very careful how you secure your nose weight. Epoxy doesn't stick well to the plastic. When I did my Squat, I roughed it up with 60 grit, epoxied BB's into the nose, then foamed it up to the bulkhead. A bit more work, but the weight isn't going anywhere, even on Imax or Vmax motors

SSenesy said:

Mine shipped yesterday too.

Just a FYI about nose weight - if the nosecone is the same material as the Squat, be very careful how you secure your nose weight. Epoxy doesn't stick well to the plastic. When I did my Squat, I roughed it up with 60 grit, epoxied BB's into the nose, then foamed it up to the bulkhead. A bit more work, but the weight isn't going anywhere, even on Imax or Vmax motors

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I use the "bamboo skewer through the tip" method.

https://www.rocketryforum.com/showt...tch-build-the-Plasma-Fart&p=306613#post306613

qquake2k said:

I use the "bamboo skewer through the tip" method.

https://www.rocketryforum.com/showt...tch-build-the-Plasma-Fart&p=306613#post306613

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pretty cool method that work. Thanks to Quake, I use it too.

qquake2k said:

I use the "bamboo skewer through the tip" method.

https://www.rocketryforum.com/showt...tch-build-the-Plasma-Fart&p=306613#post306613

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Neat idea! I may try that next time; the foam can be a bit unwieldy at times. That's a great looking rocket that I'm gonna have to add to my list

Am I seeing correctly that they're already out of these? Speaking of piranhas...

chadrog said:

Am I seeing correctly that they're already out of these? Speaking of piranhas...

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Yeah, I was a little disappointed, too. Especially since I didn't get an email.

I think as recently as yesterday morning, the Piranha kit was still available. Wanted one but decided to hold out for the Black Friday and Black Saturday sales.

Mine still hasn't shipped even though I bought it and got a confirmation. I hope they didn't oversell.

Oops, just saw this thread on the Piranha! I'll see if I can answer some questions.

On the rocksim file - yes, sorry I just did the override on the mass and CG from the prototype. We'll try to get another sim file out after things settle down.

We flew the prototype on a 5g pro29 and didn't need to add nose weight, but everyone builds different. We tend to build the prototypes very minimally with no reinforcements to stress them out.

A little bit about the design if you all are curious... This is an old design that was in the first group of cardboard and balsa nose cone kits from Madcow way back. It originally had an elliptical nose cone, but didn't sell very well. Upgraded to a 3:1 Ogive and everyone loved it, but I never got around to releasing it. Now it's in fiberglass - so I guess I still really have never released that cardboard kit

BTW, yes there will be many more available on Friday!

w00t!

Look forward to your build thread. I'm looking for mine to arrive here on Friday. I'm off the week of Christmas, I may try to build mine then.

Neat looking kit, plus the Madcow stuff is awesome. I want one!

FYI - It appears that the Piranha decal that is shown in the picture does not come with the kit.

Green Jello said:

Unfortunately I think I'm gonna give this to my son for Christmas, so I can't start on it until after then. The main reason why I bought it, is that it seemed like a cheap way to get experience building a fiberglass rocket before doing my L1 Wildman Darkstar Jr. build.

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That's kind of how I was looking at it too.....fiberglass rocket at a good price to gain some experience. Plus haven't gotten any Madcow stuff. Impressed so far with the process.

Green Jello said:

FYI - It appears that the Piranha decal that is shown in the picture does not come with the kit.

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You can get it from Stickershock for a discount.

https://www.stickershock23.com/Mad_cow_Pirahna.html