5.5 Inch idea, possible Level 2 rocket

I am posting this here because I figure it will get many more views and responses, but if it needs to be in the scratch build forum, please move it.

Getting my Level 1 last year and getting into bigger rockets has gotten me wanting something even bigger.

I have a couple of four in rockets, so I thought a 5.5 inch airframe would be a good next step. As increasing my skills every chance I get is my goal in rocketry, I figured I would try do design my own and do a scratch build. I have successfully designed, built, and flown, a 3x24mm 2.6 inch rocket, so this would not be my first scratch build, just my first big design and build.

Because it is much bigger than anything else I have designed or flown yet, I thought I would post my design here and get the opinions of those more advanced and knowledgeable than I am. It's certainly nothing fancy, but I want to make sure the design is solid.

If this design is solid and I build it and it flies well, I may very well use it for my Level 2 attempt later this year.

Thanks for any input,

Steve



View attachment 5.5 Inch.rkt

I think it is a good design. I don't know why you have the 0.5" tabs on the strakes. I'm thinking surface mount would be better, but that's a nit.

That looks like a really good L2 rocket. It will be really nice on J and K motors and push 7K on the CTI L935. At the same time, a small I will get it low and slow on those windy days when you have to fly, just not too high.

I suspect this is going to be one of your "go to" rockets and you will start thinking about a 75mm MMT in the not too distance future.

Good Luck and have fun!

Loc magnum

looks like a great design ..

I built a LOC Big Nuke kit and added a dual deployment payload bay. It was a great kit to build and fun.

working on an Ultimate Wildman kit now.. and I am loving it!

Handeman - thanks for the good words and the comments about the tabs on the strakes. I was playing around with them but was not sure they were needed. After your encouragement, I will remove them and surface mount the strakes. As this will be my only really big (for me) rocket for quite some time, I agree that it will be my go to rocket for when I want to make a lot of noise, flame, and smoke.

75mm? the price of 54mm Ks makes my eyes bulge out a little, so it will be a while before I succumb to the desire for bigger motors, but I do agree, it will be there.

Gary - thanks for the suggestion, but this thread was put together for feedback on my design. If I were to go kit, I already have a short list (Polecat 5.5 Phoenix, Madcow 4 inch FG Super DX3, etc.)

Russ - thanks for looking this over and for the feedback. I like Loc kits, and I am sure I will own a big one at some point. I am going to send my Viper IV up on two composite motors for the first time in a couple of weeks. I cannot wait for that one. Four D12s was cool, but two composite motors has me very exited. I have a Wildman Jr in the build pile, along with a Darkstar Lite, a 2.6 V2, and a Punisher Super Sport. I flew my Interceptor 54 for the first time last month, and it flew great. It was also the first time I used the Mayhem 54mm fly away rail guide, and it performed flawlessly.

Thanks again for the feedback,

Steve

Actually a Little known fact!

75mm 2-grain motors[K&L's] are way cheaper than the 54mm counterparts [K&L's]

150.00 -180.00 for 54mm's vs 120.00 for 75's same or greater impulse. That adds up quick.



I would definitely use a 75mm motor mount just to realize these savings. Most folks don't bother to check this out before building or buying motors. There are some real nice 2-grain 75's out there.

When ya really want to step it up a notch the 3 grain 75's cost same as retail on 54's !!!!

Nice project, good luck with it !!!!

blackjack2564 said:

Actually a Little known fact!

75mm 2-grain motors[K&L's] are way cheaper than the 54mm counterparts [K&L's]

150.00 -180.00 for 54mm's vs 120.00 for 75's same or greater impulse. That adds up quick.

View attachment 281000 View attachment 281001

I would definitely use a 75mm motor mount just to realize these savings. Most folks don't bother to check this out before building or buying motors. There are some real nice 2-grain 75's out there.

When ya really want to step it up a notch the 3 grain 75's cost same as retail on 54's !!!!

Nice project, good luck with it !!!!

Click to expand...

Yep,
Jim and Tim sold me on this concept a while back. Now I have a shiny new AT 75/2560 case I'm itchin to fly. First will be a K560W in my WM A.A.D. 98 Interceptor. I also ordered a WM Wild Thang Extreme to take advantage of these motors... On to building!!!

Adrian

OK, I got rid of the tabs for the strakes. I agree there is no reason for them.

Jim - you make a fine argument for the 75mm hole, so I made the change to that, as well. I fly 29mm motors in my 38mm rockets, so why not 54mm in a 75mm for the Js and kicking it to 75mm for the Ks and Ls (when I get there). Nice going on the screenshots from Tim's site. A little free plug.

I currently have five of Tim's kits, two of which are built, and 38mm is the biggest mount. I guess L2 cert and a bigger garage will invite bigger kits from Tim.

View attachment 5.5 Inch - revised.rkt