Loc Magnum Build

[crossfire]

I'm currently building the Magnum with the 54mm mount. I'm wondering where you all placed the rain buttons. On my Nukes, it was easy to separate the buttons due to the size of the fins. The Magnum's find are a lot smaller, therefore the centering rings are a lot closer. I just don't want the top of the rocket leaning off the rail. So my thought is to have the bottom rail button on the very bottom centering ring like I normally do and the too rail button on the altimeter bay. Thoughts?

Normal placement for top rail button is around the CG or a bit below. I would not put it on the av-bay. You need 2 button guidance as long as possible.

 

[berlinetta]

I'm just trying to keep the top button from interfering with the recovery system

 

[lucanica]

I've added a third centering ring at the fwd end of the motor mount tube, and epoxied 1" wood cubes (with one conformal face) to them in order to screw the rail buttons.
The actual model in the picture is a 3E version (3" motor mount), but it illustrates the idea.

Cheers!

 

[berlinetta]

I've added a third centering ring at the fwd end of the motor mount tube, and epoxied 1" wood cubes (with one conformal face) to them in order to screw the rail buttons.
The actual model in the picture is a 3E version (3" motor mount), but it illustrates the idea.

Cheers!
View attachment 519555
View attachment 519555

My 3E version has the three centering rings as well, but I ended up adding a third rail button on the av bay

 

[AlexBruccoleri]

Though not the largest, smallest, fastest, or most extreme, I can honestly I haven’t been this excited for a build in a long time!

Why the Magnum?

1) Loc rocks and the Magnum is a classic. It just so happens that my discovery of High Power Rocketry (HPR) was with the Nov/Dec 1992 issue of High Power Rocketry magazine with Wayne Anthony’s flamed Magnum on the cover. This is the issue of HPR that got me hooked, and that photo is the initial image that sticks in my mind.

2) Not sure why, but I really like 75-3G motors…I guess its just a nice size for me. I also picked up 75-2G AMW hardware and an L700 load last year. Well, the 2G and 3G 75 loads from AMW are largely progressive, meaning they have a gentle start up and therefore don’t have tremendous kick off the pad. I wanted a rocket that could achieve a minimum 5:1 thrust-to-weight ratio with only 500 Newtons of average initial thrust (ie L666 thrust curve: https://www.thrustcurve.org/simfilesearch.jsp?id=606). That ends up being a 22 lb on the pad weight. 22 lbs minus an 8 lb L666 Skid leaves only 14lbs for airframe, electronics, and recovery. I have two 4” kits with 3” holes on hand, so let’s throw them on the scale. Without recovery, electronics, epoxy, or otherwise, dry weights of the Extreme Darkstar and Air-X Delamar both were around 13 lbs…no chance in heck I’d keep it under 14lbs constructed without doing surgery on the kits…no thanks. However, I’m very confident I can build a lightweight Magnum!

3) Again, Loc rocks! I have more Loc rockets than any other brand; I love them for their simplicity and efficiency. Furthermore, I spent a bit of time with Barry and Mark from Loc at Midwest Power a few months ago. You see, I appreciate having quality rocket manufacturers/suppliers on the field at launches I attend. For instance, among others, I saw Loc, Loki, CTI, Stickershock, and Wildman present (but not necessarily vending) at MWP; each received an order following Midwest Power.

Getting back to the excitement of the build; I have longed to have a Magnum and have been on a nostalgia kick of late. After building a Dynacom Tarantula https://www.rocketryforum.com/showthread.php?t=26622 clone that blazes the skies and topped 20K on its first flight, I’m excited to build a lightweight classic that can majestically soar on lighter thrusting longer burning motors! So here we go!

First up: Magnum arrives nicely boxed from the fine folks at Loc:

-Eric-

That picture of Wayne and the Magnum still stands out in my mind too. If I recall, he flew it on a K250 but I cannot remember. Thanks for writing up your build and beautiful rocket!

 

[berlinetta]

Wayne Anthony was a small part of my L3 certification. He was the one who pushed the button. He's a great guy.

 

[AlexBruccoleri]

Wayne Anthony was a small part of my L3 certification. He was the one who pushed the button. He's a great guy.

Off topic, but do you fly at cmass?

 

[berlinetta]

Off topic, but do you fly at cmass?

Yes I do.

 

[AlexBruccoleri]

Yes I do.

We met at the last launch. I was looking forward to seeing your rocket fly on a J mojave green, but the fire issue closed us down. Nice to connect here!

 

[berlinetta]

Oh, ok. What did you fly that day?

 

[AlexBruccoleri]

Moved to pm.