Scratch Mach Buster

[RocketboyG80]

I finally got around to posting some pictures of my Mouldy Crow minimum diameter 29mm rock. I took them with my little Pencam VGA, so the pictures may be kind of blurry depending on your monitor resolution. (I need to get a good digital cam one of these days; I actually bought this one just for the purpose of putting it in a rocket, which I'll do soon.)

 

[RocketboyG80]

Here's another.

 

[RocketboyG80]

And one more.

 

[Rocketjunkie]

Looks like a good design. Now all you need is a H125-14

 

[RocketboyG80]

I decided to bring this thread back now that I have some better pics taken with a real digital camera. And unfortunately I can't fly it on anthing longer than a single use G as I put in a motor block. (there is actually an H125 on ROL now, along with two H45's) I have to remember not to do that in the future.

 

[RocketboyG80]

Aft

 

[RocketboyG80]

These are probably the best fillets I've done to date.

 

[powderburner]

If you are really going to try to break Mach 1.0, then you should think about using a tower for launch guidance and get those lugs off the rocket.

You will pay a very large drag penalty for those things, probably enough to stop you well short of your target velocity.

 

[RocketboyG80]

Yeah, I sort of regretted that when I finished it. I wasn't going to mention it until later, but I'm already working one a new one. It is made of 29mm fiberglass tubing, the same PML nosecone, and similar shaped fins made out of 1/16" G10 fiberglass. It will be 42" long. Also, I will not put a motor block in it so I will be able to fly it on 29/360 loads. Also, it will not have no lugs or buttons, therefore I will use a tower for it.

 

[havoc821]

Rocketboy,

Is that the dolphin pen cam, the same one of info central. If so, I have the same camera and I use it for all my onboard videos. The picture under my name is a still taken from a video in my backyard. Anyways, cool rocket!

 

[bachsta]

sorry im new but whats a tower?

 

[solrules]

Originally posted by RocketboyG80
Yeah, I sort of regretted that when I finished it. I wasn't going to mention it until later, but I'm already working one a new one. It is made of 29mm fiberglass tubing, the same PML nosecone, and similar shaped fins made out of 1/16" G10 fiberglass. It will be 42" long. Also, I will not put a motor block in it so I will be able to fly it on 29/360 loads. Also, it will not have no lugs or buttons, therefore I will use a tower for it.

You might want to start the fins one calibur from the back of the rocket. It is proven to reduce drag, I assume it cleans out the base drag instead of breaking it up with fins right at the aft of the rocket.

 

[DynaSoar]

Originally posted by solrules
You might want to start the fins one calibur from the back of the rocket. It is proven to reduce drag, I assume it cleans out the base drag instead of breaking it up with fins right at the aft of the rocket.

I don't recall the exact mechanism, but it doesn't need to be a full caliber. 1/4 caliber is standard on modrocs. 1/2 should be plenty. If the motor sticks out of the aft of the tube any, that'd count as part of the distance.

This is for subMach anyway. At Mach+ the least drag is from the fewest sharpest transitions. Of course you've got to get there to bust it. Plus, fins moved forward means less likelihood of landing on one and busting it.

 

[Mad Rocketeer]

Another way to reduce drag would be to add a boat tail, unless you're already at minimum diameter. That would be nicely compatible with offsetting the fins from the tail end of the rockets by a small amount. Of the two, though, minimum diameter will probably net you more.

 

[Mad Rocketeer]

[Deleted as a duplicate]

 

[GL-P]

I have a question about boattails. I got a minimum diameter rocket in the works. I'm gonna use a G55 (yeah, the OOP ones) or a G37 (EM). They both have the nozzel sticking out a little from the rest of the motor. I was wondering if I could add a boattail to this. Has anyone done this? The grey shaded area is where I want to put the boattail.

 

[DPatell]

she's hotttttt:kill:

 

[bachsta]

dont wanna steal the thread but why is a tower so expensive it looks like itd be real easy to build. oh and the ckick is a little old for my tastes