Boyce Aerospace Maxi Pershing 1A

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Ordered one But I just finished up one using Leo's 3D files. Hopefully I will be able to fly it soon.
 
Boyce must have test flew this model. How much nose weight is needed?
You load the heaviest recommended motor. They give you a CG location. You add nose weight until the rocket balances at that location.
Maxi Pershing 1A Builders Kit (shopify.com)
Actually this is better than giving you a specific weight because people build differently so CGs can vary from build to build.
I haven't contacted Boyce yet, but... do you think I could use a LOC 3.9 tube instead of the BT101?
Don't know the dimensions of the LOC tube but even if the IDs are the same (and I don't know if they are) the LOC tube is thicker.
So the nose cone lip around the shoulder might not be high enough if it was printed for the thinner tube.
Here's a pic of a clone that I modified with a BTH-80 tube instead of BT-80. The PNC-80BB nose cone contour does not quite match to the tube because It's thicker than the BT-80.
0122211533[1].jpg

But BA can give you a more definitive answer.
 
If you want a stronger BT101 you can sleeve it with couplers, leaving room for the nose cone shoulder and motor mount rings. Did this with a Super Big Bertha and results were great.
Cheers / Robert
 
Wasn't expecting delivery on a Sunday morning, but here it is:
0131211648[1].jpg

Large parts were individually bubble wrapped and taped, smaller parts were in their own baggies.
There are 4 nose cone sections, looks like they have already been sanded to remove the micro ridges.
I really appreciate that, cuz everybody knows how much I LOVE sanding. :rolleyes:
Of course, I had to dry fit the nose cone.
0131211649[1].jpg

Also ordered the 13mm powered LJ 1.
Shoulda called it the TWJ (Teeny Weeny Joe).
Should be a good small field flyer.
Dry fitted as well.
0131211650[1].jpg
Parachutes came in a couple of days ago, waiting on the main airframe from erockets.
Should be arriving in a couple of days or so.
Yowzaa.
 
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Who gets mail on a Sunday? Or a Saturday? *

I guess it was a courier delivery (or UPS).
Believe it or not, it was USPS Priority Mail.
Tracking notice showed it arrived at my local substation mid Saturday, ET of delivery on Monday.
So I wasn't expecting it today.
So how's the fruit harvest going on your farm?
We had a Hayden mango tree and an avocado tree in the back yard growing up, and a lychee tree in the front yard.
Had to keep an eye on those ripe lychee, they would mysteriously disappear overnight. Heh.
 
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My maxi Pershing kit arrived a couple days ago. Nice kit, though ridges will require filling and sanding. Thats just the state of 3D printing tight now. Still, the quality is a lot better than other 3D printed items I've purchased elsewhere.

The instructions state you need a BT-101 exactly 21.467” long. The only place i have found for this part is eRockets, who sell one 24.625” long and another a hair short at 21.4” long. Wall thickness is stated on the eRockets site as 0.021” with OD 3.938”, ID 3.896”. I hope this is the correct BT. I have a query in to Boyce Aerospace to confirm.

Also, the two motors recommended in the instructions, a F40W-6 and a G53W-7 are not listed on Aerotech’s motor page so are either obsolete or an incorrect designation. Note that Boyce tells you to use the heavier motor to calculate the required nose weight for a very specific CG.

I’d love to see this rocket on a White Lightning. If anyone has alternative motor recommendations, I’m all ears.
 
My instructions list only one recommended motor, the AT F44W-4.
The motor mount is a BT-50 tube, 24mm motors only.
Are your instructions different?
 
I guess I also need to contact Boyce. The centering rings are for a 29mm tube, but instructions say to mount a BT-50 tube in the rings.
Hoo boy.
 
I just checked the online assembly instructions, and apparently I received an outdated sheet:
0201210721[1].jpg0201210722[1].jpg0201210722a[1].jpg

Now I have to scavenge an 8" 29mm tube from one of my other builds.
Dang. Should have known to skip first production runs by now.
BTW there is a G53 RMS motor but it's a FJ, not W.
PS F44W is a 24mm AT EconoMax. Maybe use with an adapter?
EDIT: Scratch the F44, received an email from Alex that the 24mm motors require too much nose weight so they went with a 29mm mount.
Also no F50W but there is a F50T (Blue Thunder) SU motor.
 
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Looks like a nifty kit (Pershing 1A is always an interesting subject) but I have to say that the instruction to cut a tube to 21.467" is quite ridiculous.
 
Looks like a nifty kit (Pershing 1A is always an interesting subject) but I have to say that the instruction to cut a tube to 21.467" is quite ridiculous.
Yeah, I ordered the 21.4" tube from erockets.
The .067" difference is about 1/16".
Well within factory tolerances, maybe I'll get one cut a little long. :D
 
Easy assembly.
0205210021[1].jpg
Per instructions, there is a gap between two sections of the nose cone.
I suppose emulating the real one.
Four of each set of fins is supplied, but only three are used.
Both launch lugs and conformal rail guides are supplied, opted for the rail guides.
The two charge retainers go over the US ARMY decal. I wonder what glue works on plastic to decal?
:D
0205210031[1].jpg

Laters.
 
Rocket isn't primed/painted/decaled yet but put some nose weight in to balance to the recommended CG.
Comes out to 175 grams, or 6.2 ounces.
Leaving the nose cone segments unglued cuz I may have to tweak that after finishing.
(Loaded with a G76 RMS reload and a 29mm case).
Empty weight of the rocket is 552.6g./19.5 oz.
BTW instructions recommend two 36" chutes.
When I plug in the weight for the rocket with expended motor and RMS casing (22.2 oz.) into the Parachute Size Calculator at Rocket Reviews with a 15 fps descent, I get ONE 36' chute recommended.
So my question is, are two 36" chutes overkill?
Would like to hear from the collective mind here.
Thanks.
 
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