Madcow Big Fizz

[Rex R]

went and ordered me one, ya know if one were judge by search results one might get the impression that it isn't the most popular rocket around. looking at the 'official' rocsim file it looks to be a nice low cost flyer should fly nicely on most 2-grain 38s. the design file does show some things that I am likely to change (but I will wait until I have it in hand before firm up my plans), I am thinking to; add a length of Kevlar to the shock cord, the motor tube looks a tad bit short at 8" and will be extended to 11", and a 3rd centering ring will be added(assuming that MC hasn't already done so). so is it that unpopular that no one has one...or do you just don't want to admit it? any photos of this bird?
Rex

 

[MikeyDSlagle]

The big fizz the first Madcow I had on my wish list, when I first discovered them a few years ago. But I never ordered one. Still like it but it hasn't found it's way into my fleet yet. Chris Short flew one at our last launch, if it can survive what he stuffs in there then it's gotta be pretty tough. Lol.

 

[afadeev]

went and ordered me one, ya know if one were judge by search results one might get the impression that it isn't the most popular rocket around. [...] so is it that unpopular that no one has one...or do you just don't want to admit it? any photos of this bird?
Rex

This looks like a great kit at a great price point.
Kinda similar to the PML BumbleeBee I built earlier this year.
https://publicmissiles.com/images/bumblebeeholding_0017-.jpg

The single point of concern for me would be huge swept-back plywood fins.
Huge and swept-back makes for cool look, but I've had terrible luck with plywood fins on mid-/HP-rockets. They break. You can repair them, but they break again at the repair point, unless you gauge them out of the TTW mount and replace them.
Long story short - I would consider replacing plywood with G10 fins.

a

 

[MikeyDSlagle]

This looks like a great kit at a great price point.
Kinda similar to the PML BumbleeBee I built earlier this year.
https://publicmissiles.com/images/bumblebeeholding_0017-.jpg

The single point of concern for me would be huge swept-back plywood fins.
Huge and swept-back makes for cool look, but I've had terrible luck with plywood fins on mid-/HP-rockets. They break. You can repair them, but they break again at the repair point, unless you gauge them out of the TTW mount and replace them.
Long story short - I would consider replacing plywood with G10 fins.

a

Maybe you should sort out your recovery. Are you using a parachute at all? I've flown several HPR with plywood fins and have yet to have one break. My Madcow 4" Cowabunga gets flown a good bit with no damaged fins. I've seen paper/plywood rockets come in fast under tangled shoots, one an Estes Partizon, with no damage to the fins. Some of the airframes didn't survive but the fins were fine. My Tyrannosaur came in at 26 ft/s, 10 lbs of rocket...no damage... :-/

 

[Exactimator]

This looks like a great kit at a great price point.
Kinda similar to the PML BumbleeBee I built earlier this year.
https://publicmissiles.com/images/bumblebeeholding_0017-.jpg

The single point of concern for me would be huge swept-back plywood fins.
Huge and swept-back makes for cool look, but I've had terrible luck with plywood fins on mid-/HP-rockets. They break. You can repair them, but they break again at the repair point, unless you gauge them out of the TTW mount and replace them.
Long story short - I would consider replacing plywood with G10 fins.

a

Those fins would be my concern too. Any fin that extends past the bottom of the airframe is prone to damage, whether it hits hard playa or sticks into soft dirt and twists as the rocket tips over. They'll take a beating.

 

[Wallace]

Since I didn't see any images of Big Fizz...

 

[Flyfalcons]

I have come close a couple times to getting one along with an upscale Alpha vinyl set, but to me it just wouldn't be as interesting as I would like when I start getting into that size range.

 

[Rex R]

got the order today(no damage). after reading about the fizz not being a true upscale alpha well, that is correct but, after comparing a true upscale to the kit is a bit misleading. even if one can find/ make an 11.27" long nose to go with the supplied airframe(which is the correct length), it would still be roughly 2" short. the difference is the fins, the MC fins are 85% of the upscale size. the full scale fins are huge.
there are somethings that I will likely change, like the standard nut to a lock nut for the supplied eye bolt, but overall the kit design is sound.
Rex

 

[amarillo_rocket]

I have flown one several times. Great flying rocket. The fins so far have not been an issue. I didn't do anything extra to the fins like FG although I did think about it. It flys real nice with a small H motor. I use a Jolly Logic Chute release for recovery because it reduces drift. Overall it is a very nice kit and inexpensive.

 

[qquake2k]

I think it looks like a fun flyer. It reminds me of the LOC IV, which was my first 4" rocket. I did break a fin on my IV, but they're only 1/8" plywood. The Fizz has 1/4", which are much more rugged. I would be fine with the stock 38mm motor tube and two centering rings. But I would go with a 42" or 48" chute, instead of 36". OR says 22fps on a 36", which is too fast for my comfort. I would also add a couple of ounces of nose weight to get the stability above 1.

View attachment bigfizz.ork

 

[Rex R]

that is my main quibble is that the instructions call for a pad c.g. of 30" from nose tip...I would suggest 28.5" as the furthest aft for a pad cg.
Rex

 

[o1d_dude]

One of our local rocketeers has a Big Fizz that he's painted and decaled in the fashion of an Alpha. Quite nice, actually.

As to modifying your Madcow kit, go for it. Can't say that any of my six(!) Madcow kits has ever been built without some modifications ( extra centering rings, modified nose cones, kevlar recovery cords, etc.)

 

[Rex R]

I feel that I would be remiss if I didn't point out that most of the changes discussed here are not essential, the kit can be built as per the instructions, one can even do internal fillets using just two centering rings(okay so one would have to deviate from the instructions to do so)and have a nice rocket.
Rex

 

[Thorfire]

Here's a photo of a big Fizz (modified with a long Madcow nosecone) Next to a upscale Alpha III I made from a 4" LOC nosecone.

 

[qquake2k]

Hey, nice Alpha III!

 

[grouch]

Geez Quake, that's awesome!

 

[qquake2k]

The Alpha III was my very first rocket in the 70's. I had to do an upscale.

 

[kswing]

Here's my Big Fizz that I've styled as an upscale Alpha. I switched out the nose cone to one that I thought looked more like the original Alpha. I've flown it twice on a low H and an I140 and it's worked well both times. I also replaced the parachute with a larger one to be a bit easier on the large fins. I use a JLCR so that it doesn't drift as much.

 

[qquake2k]

Very nice, Ken!

 

[Rex R]

so I got it built and painted. used a length of Kevlar sc to keep the nylon sc out of the ejection charge heat, and I added a 3rd centering ring to the motor mount (just forward of the fin tabs). when I ordered the kit I also ordered an extra pair of centering rings, 1 was used in the traditional way, half was used to 'bulk' up the rail button screw locations(ring was cut into 1/4ths). I used 90g of shot + 15g of epoxy were poured into the nose to let me fly up to 3 grain 38s should I want to . all up pad weight with an H148 approx. 1600g. so it got its' first flight Saturday, as I figured it had a very nice flight on an H148-8R to roughly 1500' landed about 40' from the pad and stuck the landing(very light winds). I am thinking that it shouldn't be flown when the ground is frozen, other than that it is a fun rocket.
Rex