Can't decide: Aerotech Strongarm, or NCR SA-14

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Bill S

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I'm looking to get my second mid-powered rocket (first was an Estes Executioner), and am having a hard time deciding between the Aerotech Strongarm and North Coast Rocketry's SA-14. Strongarm looks to have less gluing needed, but is nearly double the cost.

The looks are similar, though I lean towards the SA-14 for appearance.

Both use similar engines, weight is fairly close. I don't plan to fly over 1000 feet normally, as I don't have a chute release or a larger area to fly in (might be able to fly at MDRA once in a while over 1000 feet).

Are there any significant cons to either rocket, and are there any common modifications you guys make to yours?
 
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Banzai88

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I was rather disappointed with my NCR SA-14 kit. It was the fourth MP rocket that I built (coming from the Leviathan/Argent/MDRM progression) and parts fit was incredibly sloppy with the centering rings and fins compared to the Estes kits.

That said, I do fly it quite often. Being relatively light and having some room in it, I use to to do low flights and sometimes parachute clusters.

Due to the fact that I got one or more of the side strakes out of perfect alignment, it spirals on it's way up......a perfect combination with a smoky motor that is always a crowd pleaser!
 

readytorock556

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I’ve built a Strong Arm and a Lance Delta from NCR and the NCR build is very robust and can take some real abuse. Still you’ll be happy with either decision. The Strong Arm does come with motor retention and a chute so that’s a big plus.
 

K'Tesh

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Both... If one of them uses a piston, I would replace it with a baffle.
 

JLP1

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Strong Arm is a good kit I'm finishing one now. Here's a couple of things to remember (1) AT has you put the launch guides on before you do the strakes if you do they will get in the way if you use their strake alignment guide. Do the strakes first then the guides (2) When you set the fins put a motor in the engine tube that will give you something solid to push against when setting the fin locks. Double check the fin locks make sure you hear the click and do a visual check. (3) The fins and the strakes are injection molded styrene plastic they are soft and they are not perfect so take your time on the alignments. My strakes were like worms and I had to get another set. Here's a pic showing my set up for doing the strakes with laser alignment. I found a thread on here that used a method of epoxy and CA to set them and it worked pretty well. Overall a nice kit. 👍
 

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MoeFaux

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I built the SA-14 as my first MP a few years back and had no issues at all with instructions or components. Since it built nicely, looks good, and flies true, I'd be hard pressed to justify paying twice as much for another kit to get the same result.

The ONE complaint I had about this kit was the "decals". The kit provided two sticker sheets rather than vinyl or waterslide decals, which I greatly prefer. As long as you're patient with the application and plan on painting the rocket white like it is in the pictures, this isn't much of an issue.

Also - here's my build tip: If (like me) you have no intention of carrying cargo or employing dual-deployment, I would do away with the cargo bay entirely. Probably just personal preference, but I would like it better if it separated at the nose cone rather than mid-body. If I were doing it again, I would glue the upper cargo bay tube directly to the main body tube, relocate the bulkhead up toward the nose, drill holes it like you were making an ejection baffle, then attach the chute and cord directly from that to the nose cone.
 

Bill S

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I built the SA-14 as my first MP a few years back and had no issues at all with instructions or components. Since it built nicely, looks good, and flies true, I'd be hard pressed to justify paying twice as much for another kit to get the same result.

The ONE complaint I had about this kit was the "decals". The kit provided two sticker sheets rather than vinyl or waterslide decals, which I greatly prefer. As long as you're patient with the application and plan on painting the rocket white like it is in the pictures, this isn't much of an issue.

Also - here's my build tip: If (like me) you have no intention of carrying cargo or employing dual-deployment, I would do away with the cargo bay entirely. Probably just personal preference, but I would like it better if it separated at the nose cone rather than mid-body. If I were doing it again, I would glue the upper cargo bay tube directly to the main body tube, relocate the bulkhead up toward the nose, drill holes it like you were making an ejection baffle, then attach the chute and cord directly from that to the nose cone.
I don't plan to carry cargo, not sure about an altimeter, nope on dual deployment. May use a chute release at some point, because I'd like to fly the rocket over 1000 feet and actually have a good chance of getting it back. :) Baby steps for sure.

I didn't realize the SA-14 separated mid-body. If I changed it to separate at the nosecone, I'd be tempted to use a stuffer tube though, so maybe that was why they designed it to separate mid-body?
 

MoeFaux

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I didn't realize the SA-14 separated mid-body. If I changed it to separate at the nosecone, I'd be tempted to use a stuffer tube though, so maybe that was why they designed it to separate mid-body?
Hmmm - a good thought. Someone with way more XP than me would have to tell us if that's necessary or not, but I think it's a damn good idea. You could then completely replace the forward bulkhead with a 29mm baffle at the end of the buffer as your recovery system's anchor point. That would allow you to skip the steel cable and forgo the nomex sheet (or wadding, of that's your style), as well. The differences in weight, cost, and effort would all be nominal, and your end result would be slightly cooler and easier to fly.

I've got my eye on the Vektra for future build, so maybe I'll get to use all these tricks myself. . .
 

dpower

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I like the AT kits, they're quick to build, require no sanding, and look great. If you're flying in cold weather, though, get the NCR - the AT plastic fins are brittle in the winter!
 

3stoogesrocketry

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Do your self a favor and just buy both now. You want them both , you will wind up with them both before long lol
 

K'Tesh

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Bad experiences with pistons? I've not yet dealt with one, so I'm curious. . .
Personally? No. Pistons violate the KISS principle and are an invitation to Mr, Murphy's Law to be involved in your launch. Baffles have no moving parts, there's less to go wrong. Besides, I've read too many stories about how a rocket with a piston has lawndarted. The going theory is that if the body tube's interior is not thoroughly cleaned between flights, the soot from a previous launch can cause the piston to jam.
 

waltr

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Yes, the problem with pistons is soot build up that must be cleaned and/or sanded between flights.
Weather changes (temperature and/or humidity) can change the BT size causing a tight piston.

When they work they work well.
 

bad_idea

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Pistons and baffles are not direct equivalents: both shield the chute/streamer from ejection charge damage, but the piston also gives the chute/streamer a direct shove. That shove can aid deployment, particularly in tightly packed tubes, but the piston can hinder deployment if it seizes, so care must be taken in preparing and packing. As with many things, they are a tradeoff. I like them but understand why many do not.
 

Back_at_it

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Both... If one of them uses a piston, I would replace it with a baffle.

I'm going to agree with this. I only have two Public Missile rockets that had the piston ejection. After fixing my IO twice due to the piston getting stuck sideways I ripped the who thing out and built a baffle using a coupler and plywood. Never another failure.
 

Bill S

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Well I'm definitely not going the piston route. :)
 

MoeFaux

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Sorry, Bill S, if we're hijacking your thread, BUT. . .

Personally? No. Pistons violate the KISS principle and are an invitation to Mr, Murphy's Law to be involved in your launch. Baffles have no moving parts, there's less to go wrong. Besides, I've read too many stories about how a rocket with a piston has law darted. The going theory is that if the body tube's interior is not thoroughly cleaned between flights, the soot from a previous launch can cause the piston to jam.
Given the aforementioned KISS principle, I'm very curious why baffles aren't more standard issue. They're as cheap and easy to build as a motor mount, they don't cost any more or weigh any more* than a corresponding nomex chute protector. They simplify the re-stuffing process in the field, they can provide a floor to your recovery bay to minimize the effect of weight shift at launch, and they offer a little freedom to adjust your CG when building.

Is there some drawback I don't know about (noob that I am)?

* I'm aware there is some nuance in the weight comparison that could be argued. An apogee baffle for BT60 at 7.9g is nominally lighter then the 6x6 nomex at 8.4g, but after a bit of glue, the scales are likely to tip slightly the other way. The same baffle for BT80 weighs 30g compared to a 9x9 at only 18.5g, BUT that baffle includes metal mounting hardware that would otherwise exist elsewhere on the rocket . . . Any actual differences seem small enough to be negligible.
 

Donnager

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Most baffle systems trap black powder residue with little to no way to clean it or dump it out.

I don't fly my baffle rockets all that often, and haven't had this be a problem, but I can see where it would become one.
 

Warren Baker

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I built the Strong Arm. I took a lot of extra time and modified it to look as much like the missiles that we used while I was on surface ships with the Navy.
I really like the build and looks of rockets more than flying them.
The Strong arm is the flagship of my fleet! I did the painting with automotive base color clear coat and cleared over the decals and pinstriping.
I have a few better photos but not here.
 

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