Lakeroadster's "Hammerhead Shark"

[neil_w]

That's certainly a good-looking swing test. And that's certainly a ton of ballast for a rocket that size.

It's *always* a possibility that a sim will be less than 100% accurate on weird designs like that. If that all works in real life then that's great. Ultimately, the launch will tell the tale.

 

[Daddyisabar]

A little over stable on a calm day won't hurt on the first flight.
Horrific amounts of no good, stinking, performance robbing nose weight are required for silly oddrocs. The more sinful the bird, the more abominable dead weight must be put forward. Hammerhead nose cone, asymmetric fins and the motor in back add up to a great deal of sin, making redemption harder to achieve. Trust in thrust and ye shall be saved.

 

[lakeroadster]

Looks good, pretty clearly stable, I'd say. I'm curious, did you try without the nose weight?

Added the "no ballast" swing test to post # 148

 

[mbeels]

Oh man, yeah. It looks like that preferred to go backwards actually. So definitely some nose weight!

 

[Daddyisabar]

Our RSO hates bulbous nose cones. He hates fins up front, especially thick bulbous ones placed in one plain. Yes, our RSO would be a hater on this one. Creating a lot of choppy, vortex filled air up front and how that will impact the fins behind is quite complicated math. The only way to beat the scientists is with brute force. Get enough inertia off the rod or rail to keep it going up no matter what the silly aerodynamics might say. Just like anvil flying. Brute force rules the world. Every thing you need to know you learned in Kindergarten. Mindsim, pray and push the button in the bunker. By the pictures I have seen lately it looks like the top folks are still doing it that way.

 

[Daddyisabar]

Here ya go.... pretty wonky without the extra nose weight... There is no added ballast in the nose cone... and the motor is installed.

String moved to the new CG.

Power and nose weight rule! Solves 95% of yer problems and that ain't bad!

 

[lakeroadster]

Our RSO hates bulbous nose cones. He hates fins up front, especially thick bulbous ones placed in one plain. Yes, our RSO would be a hater on this one.

Is your RSO Debbie Downer? Heaven forbid somebody try something different.

 

[Daddyisabar]

Is your RSO Debbie Downer? Heaven forbid somebody try something different.

More like Robo Cop! Fortunately after all the explaining you could get an assignment on the far far away pad because everyone wanted to see the rocket fly or crash. Just like NASCAR. Never had a problem with rockets with one motor in the back, always stable. If everything lights on a cluster things usually went very well. Stability should not be a problem. Just follow the basic rules by not bending them too much and don't skimp on thrust, rod length or conditions. I predict lots of fun!

The funnest part is pointing out all the quirks and features and then have it fly!

 

[Nytrunner]

Is your RSO Debbie Downer? Heaven forbid somebody try something different.

When you're responsible for the crowd safety and have to sign off on all the rockets (and the insurance copay when something goes wrong), you approach things with a little more caution than "pray and push the button"

 

[lakeroadster]

Applied another coat of primer. This time I'm using Rustoleum 2X.

Not sure yet but I might just shoot another coat of this in a couple days and use it for the upper color of the shark, then spray the underneath with an off white.

 

[kuririn]

Painted shark mouth or decal?

 

[lakeroadster]

Painted shark mouth or decal?

Painted. Not really going for an "Odd Roc" look on this one. Going for more of a realistic look.

At least that's the thought as of today...

What's your thought?

 

[OverTheTop]

 

[lakeroadster]

View attachment 418579

Very cool... but not really going for the "odd roc" look... more like this..

 

[lakeroadster]

When you're responsible for the crowd safety and have to sign off on all the rockets (and the insurance copay when something goes wrong), you approach things with a little more caution than "pray and push the button"

A fair amount of R&D and OR Simulation work has been done... but I get your point.

 

[BABAR]

Very cool... but not really going for the "odd roc" look... more like this..

View attachment 418773
View attachment 418774

Okay, first, this puppy by definition is an OddRoc no matter HOW you paint it!

Second, if you are trying to make it realistic, I get the eyes on the stalks, the painted on mouth, the painted on gill slits, the fins.....

that would make the motor.........

 

[Nytrunner]

A fair amount of R&D and OR Simulation work has been done... but I get your point.

Swing test looked really promising.
For a design like this that breaks the underlying assumptions used by OR for grounding its calculations, extra measures like the swing test are needed because OR's result is ....suspect.

Something I'm curious about is how the rocket would perform if the "head" was vertical during swing. If there's any destabilizing lift forces acting on the head, that swing orientation may show it

 

[lakeroadster]

that would make the motor.........

Ocean waste the shark ate Remember the scene from Jaws where they cut open the shark?

Go to 3:50 here...

 

[lakeroadster]

2nd coat of Rustoleum 2X. Next up... painting the belly white

 

[Daddyisabar]

Googly eyes! The big kids will love it.

 

[lakeroadster]

White Belly

 

[K'Tesh]

Sweet!!!

I love the steely look in its eyes.

 

[BBowmaster]

Nice way to add nose weight too. This is a very unique rocket.

 

[neil_w]

Lookin' good.

 

[mbeels]

Very nice. That is undeniably, unquestionably, a hammerhead shark. I should bring out my baby krakens for the shark to hunt, and have an aquatic themed launch.

 

[Vdutel]

Went out to local school where I shoot LPR’s. Sent a Baby Bertha, Fat Boy and a Bigg Betty up today. I have to go back out in the morning to retrieve Big Betty, she went over a fence and want to ask to go onto property. Her first flight and she flew great.. I had to change chute as it had hanger damage and new chute was a tad bit bigger and she sailed into the

 

[K'Tesh]

Very nice. That is undeniably, unquestionably, a hammerhead shark. I should bring out my baby krakens for the shark to hunt, and have an aquatic themed launch.

Holy Mackerel!!! Flying Fish and a Sharknado

 

[BABAR]

I wonder if anyone has ever tried to launch a rocket from two adjacent launch rods simultaneously?

I know it is a Hammerhead, but I hope for a Great Height launch report! As usual, you keep coming up with some amazingly unique designs

 

[neil_w]

I wonder if anyone has ever tried to launch a rocket from two adjacent launch rods simultaneously?

I'd be really nervous about binding.

 

[BABAR]

I'd be really nervous about binding.

On the Master Engineering Expert’s rocket? It wouldn’t dare!