Maxi 4" Boyce Aerospace Hobbies Pershing Build Thread (1/10 scale)

[ljwilley]

Here is the thread in which I will be logging the build of my 4" maxi Pershing from Boyce Aerospace hobbies.

The MGM-31A Pershing was a solid fueled, 2 stage missile developed by the US military to replace the Redstone missile. (the picture below)

The kit is a builders kit, so I had to provide my own tubes/chut/ect. I have just recently received the parts, so here is the full layout:


I hope you enjoy or learn something from this build!

 

[ljwilley]

Finished putting the nose cone together. Used my NAR member card to space each of the pieces, as it made sense.

 

[kuririn]

You may want to double check and see if the instructions have been amended to the new CG recommendation:
https://www.rocketryforum.com/threads/corrected-boyce-maxi-pershing-1a-cg-cp-locations.167202/

 

[ljwilley]

Extra nose weight for sure, got it! I was going to be doing rocksim and swing tests either way.

 

[MPiKM]

I've seen those on eBay, but was reluctant to buy one because of its price. How is the quality of the parts,ease of build,etc? I wanted to get this one and the Nike Hercules.

 

[ljwilley]

The 3d printed parts seem to be of very good quality. Like any 3d printed parts, you would want to sand them a bit to smooth them out. I think it is worth the price.

 

[ljwilley]

Build should not be too hard as long as you have built a rocket before, or at least are good at building things.

 

[ljwilley]

Finished the motor mount with a Kevlar shock cord mount. The motor tube is very short compared to what was recommended, but it will do. So far build has been very easy.

 

[ljwilley]

Motor mount glued in:

 

[ljwilley]

I also checked the instructions, and the CG location has been updated. No more unstable flights.

 

[ljwilley]

Wow! Started building this morning and I'm already done! Very, very easy to build, I would recommend. I will paint and put decals on as soon as I get a break in the weather. Looks like this will be a very short build thread.

 

[billpr]

Look great. Thanks for posting

 

[ljwilley]

I put a lot of nose weight in it so I am not worried about stability. I will do some Rocsim tests so that I can choose a motor for it- I really want to fly It on an F25 for a low/slow flight but not sure if the motor is powerful enough. Without the motor, the rocket weighs approx. 750 grams. Any thoughts?

 

[ljwilley]

Just found a very cool video of a real Pershing launch!

 

[ljwilley]

Just did a Rocksim simulation to see if it was stable with an F25- it unfortunately is too heavy for the F25. I will be launching it on an F67.



.rkt file is attached too. I included the cable covers and fin base things in the design- There are no Maxi Pershing .rk or .ork files on the internet for the pershing that include the cable covers/fin bases, so I thought I would post this file here for your convenience.

 

[ljwilley]

A few times this morning the rain stopped, giving me just enough time for painting the Pershing. I put the decals on thin afternoon!


What do you think!

 

[ljwilley]

The .rkt file above was the wrong one- I fixed it now but if you downloaded the other get rid of it and download this one!

 

[neil_w]

Looks great.

 

[MPiKM]

Looks cool!

 

[Danomite45]

ljwilley,
Any updates? Did you fly it yet?
anything you would have done differently?
My wife bought this kit for me for Christmas, and I'm planning on putting mine together in a few weeks.

 

[ljwilley]

Planning to fly it in two weeks at Tri Cities Rocketeer's Missile madness, may 4th and 5th. No new updates, but I will fly it and give you guys videos/ launch report!


Edit: Good luck with your build!

 

[ljwilley]

The Rocsim file said it was stable, but this morning I decided to so a swing test just to be sure. The swing test confirmed the stability. We are go for launch!

 

[conneryc]

Well I have run into a bit of an issue with my build. I ordered the Saturn V replacement body tube from Estes for this build....and had assumed it was the correct length since that was the tube that was mentioned. I didn't notice the problem until I started putting on the decals and realized that the tube is 3" longer than the plans call for. Wonder where I need to set up the CG now.....I'll update the RockSim file and see what it says I guess.

 

[Danomite45]

The good news is that it’ll be easier to get your rocket to be stable.
The bad news is that it’s not to scale, if you care about that.
I’d rather sacrifice scale for stability.

 

[Antares JS]

Well I have run into a bit of an issue with my build. I ordered the Saturn V replacement body tube from Estes for this build....and had assumed it was the correct length since that was the tube that was mentioned. I didn't notice the problem until I started putting on the decals and realized that the tube is 3" longer than the plans call for. Wonder where I need to set up the CG now.....I'll update the RockSim file and see what it says I guess.

Longer usually means more stable.

 

[kuririn]

. I ordered the Saturn V replacement body tube from Estes for this build....and had assumed it was the correct length since that was the tube that was mentioned.

Just curious, but where did you hear that?
Instructions call for a BT-101 tube cut to 21.467 inches.

 

[ljwilley]

I just bought the BT101 from erockets cut to 21.4" long. That may have been easier for you. But, longer does mean more stable, or at least easier to make it stable.

 

[kuririn]

I just bought the BT101 from erockets cut to 21.4" long. That may have been easier for you. But, longer does mean more stable, or at least easier to make it stable.

I also bought the 21.4 in. tube from erockets.
The difference in length of .067 in. is about 1/16th inch.
Negligible IMHO.

 

[ljwilley]

Yes, unless you are going for a scale competition, 1/16" is not really a big deal.