Aerotech Strong Arm build thread

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trippkid

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Here is my latest build, an Aerotech Strong Arm kit. I have built a couple of Aerotech's kits before and decided to change some things up from the instructions a little bit. I won't be using the motor hook, I have an Aeropack retainer for this ready to go. Also, I think I will be using some of the cooling mesh and will still be using the thrust ring, only it will be spaced in the motor tube for my 29/240 case. I think that is the largest I want to go with this one. I will also be using some nylon cord for part of the shock cord, along with a homemade shock cord protector and blanket for the parachute. I know all of this may be overkill and will add a small amount of weight to the rocket but I am not trying to break any altitude records. The instructions say to use medium CA glue on the build, but I will be using mostly epoxy and JB weld. Again, overkill, but I prefer to work with epoxy, gives me a little more working time and it cleans up easier if you use a little too much, IMO. I don't know when I will get to paint it, it is still pretty cold here in PA. Here are a couple of pics.

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More pics. Well I tried to upload some but they are way too big for the 390Kb limit. I guess I will have to reduce the size some or put them up on photobucket. Sorry about that. Hope to get them up soon.
Matt
 
Ok, I think I can post them now. The first couple are of the parts and the instructions, these are still too big I had to put them on Photobucket to get them on.
Matt

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As you can see by these pics, I test fitted the fins in the slots and things did not line up the way they are supposed to. The slots are about 4 mm too short or the tube was off by that much when it was cut. I extended the slots roughly 4mm so that the fins lined up flush with the end of the body tube. It turned out pretty well. I extended the launch lug slots too(I didn't have to do this as it turns out, but at the time I thought that I'd have to make them a little longer because of the slots being off that much).

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I also rough cut the strakes, I will give them a final shape later.

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Epoxy is unecessary to assemble AeroTech kits. It just adds weight.

Trust me, my name is on the instruction sheet. ;) :D
 
Here are some pics of the motor tube and the ejection baffle. I had to offset the the finlok rings and centering rings a few millimeters because of the Aeropack retainer. I installed the thrust ring so my 29/240 case will fit(roughly 8.5" from the aft end of the motor tube. I did this so I could use some of the cooling mesh for the baffle. Also, I made the shock cord protector and gave it 3 baths in fireproofing solution, I made the blanket also. I sanded body tubes, then smeared some drywall spackle on them to fill the spirals, then sanded smooth. Thanks for looking.
Matt

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Another tuffy rocket in my fleet is the Strong Arm .Great choice on the Aeropack and cord/parachute protectors and no use of the elastic ,wish I would have done that to mine ,although I gutted mine and made it to fly reloads ,just added another plywood CR and my own retention system.

Keep up the good work !


paul
 
Thanks Paul, I am using the elastic too, it gets tied to the nylon cord about 5-6" outside the end of the tube. I have never had any problems with zippers, but I have had the NC pop off and come back and crinkle the tube some, so I thought it wouldn't hurt to add a little extra protection. Have a good one.
Matt
 
Thanks Paul, I am using the elastic too, it gets tied to the nylon cord about 5-6" outside the end of the tube. I have never had any problems with zippers, but I have had the NC pop off and come back and crinkle the tube some, so I thought it wouldn't hurt to add a little extra protection. Have a good one.
Matt

Good idea.I`ve had the elastic break inside the tube ,total bummer but got a Kevlar SC tied in it`s place.

I never knew I could swear so much in one day ;)


paul
 
Here are some more pics of the motor tube installed and the fins being put into the slots. I used CA glue for the fins and 5 min. epoxy for mounting the motor tube assembly into the body tube. Almost a rough finish, still have to shape the stakes and mount them and put on the motor retainer.
Matt

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The final pics until I can paint outside, could be awhile, we just got some more of the white stuff outside. I smoothed out the NC with spot putty filler. I got the strakes finished and mounted with 5 min epoxy. Also, I put an eye bolt in the NC and JB welded that in place. Pretty much done except for some minor body work before painting. Thanks for looking.
Matt

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The last batch for now. I installed the launch lugs and the Aeropack retainer.

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Nice job brother ! Yup ,I think many folks here know what you mean about winter and the lack of painting to be done.I`m glad i have a paint booth for smaller components and parts as well as smaller kits ,or I would probably go mental.I just hate having finished rockets lying around waiting for paint :(


Cheers


Paul t
 
I know, I have about 10 of them waiting to be painted. I did get to shoot one coat of primer on some of them last week, warmer temps should be right around the corner, although we are supposed to get a couple more storms in the next week or two. But, yes I do not like having them laying around, I guess I lose a little motivation to get them finished. Have a good one Paul, and thanks.
Matt
 
Here are some pics of the motor tube and the ejection baffle. I had to offset the the finlok rings and centering rings a few millimeters because of the Aeropack retainer. I installed the thrust ring so my 29/240 case will fit(roughly 8.5" from the aft end of the motor tube. I did this so I could use some of the cooling mesh for the baffle. Also, I made the shock cord protector and gave it 3 baths in fireproofing solution, I made the blanket also. I sanded body tubes, then smeared some drywall spackle on them to fill the spirals, then sanded smooth. Thanks for looking.
Matt

Nice build! I've always loved the Strong Arm. It was my first G rocket. I too use 5 minute epoxy because of the cure time. What kind of material did you make your shock cord protector and blanket out of, and what are you using for fireproofing solution?
 
Capt., I am just using a heavy canvas then soaking in a solution of Boric acid and Borax, about a 4:1:1 mix, the last :1 being HOT water(I don't think the water part is critical, you need enough to soak the material and enough to fully dissolve the boric acid, I normally only do small batches with only a cup or two of water). Make sure the water is boiling or very close to it, otherwise the boric acid won't go into the solution very well. The directions can be found on the net, there are a couple of formulas to get the job done, this one is easy to obtain, I actually already had the stuff at the house. I soak the fabric for a couple of seconds then let it air dry, it is pretty good at this point as far as being flame retardant, but I will give it two more baths in the solution and letting it fully dry between applications. It is not 100%,imo, but it will definitely do the trick, you can hold a direct flame to it for more than a couple of seconds without out it catching fire. I guess that is a bad choice of words, the stuff never really catches fire, but it will start to smolder a little if you keep the flame to it. I will have to try to burn it with a torch, I just used my Bic the last time I was testing it. I think it will work pretty good in place of the Nomex, I just don't have the $ for all that extra stuff sometimes and have to make due with what I do have. Have a good one, thanks for asking.
Matt
 
Sorry, I guess I should have asked the moderators first if it was ok to list the ingredients. If this is not allowed please remove the post. I don't think it is a problem, but who knows. AS ALWAYS WITH MIXING CHEMICALS, WHERE PROPER PROTECTION FOR YOURSELF!
 
load and fly that puppy ..I predict there are bigger and more challenging rockets in your future...don't let details and experiments bog you down.
it's an aerotech strongarm kit.. dozens of stock builds have probably flown and recovered successfully since the first post including mine built with superglue.
actually it's my wife's rocket built stock and has 8 flights on it with zero mods and stock motor hook.

we consider it one of our many trouble free/ build and fly rockets ,and it scoots !
I built and painted it the day we brought it home.(with the wife's girly pastel paintjob ...lol)
 
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Hey, thanks, I have a few in my fleet, this was the latest one, just put together a nice little fiberglass kit about a month or so ago. I do like the Aerotech stuff though, I have an Arcas, Sumo, and a Tomahawk waiting to be built, and a couple of Madcow kits yet waiting. I just want warmer weather and clean launch area, our club hasn't done much winter launching because of the snow. The next one should be a go, I'm hoping. Thanks again.
Matt
 
Arcas is a great kit and impressive in size ,sweet flier (until the ejection charge fails to go off...then SPLAT)
Tomahawk is another nice ,sturdy kit.I pretty much have all the A/T kits except the SUMO ,but I find it kind of pricey for a short fat NC3F kind of kit.

MadCow are also great kits ,the fiberglass offering are really nice ,but all the madCow kits i`ve built are well made !

I just got a Super DX3 in the mail yesterday ,but if I would have known ,I would have bought the all fiberglass version that just came out :(

Keep up the good work chum !

Paul T
 
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