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L1 build thread
#1
Well the time has finally come! It is time to build the rocket I will attempt my L1 certification with. My rocket of choice is the Madcow 4” Little John with a 38mm motor mount.
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 I am going to attempt to do my first build thread here so bear with me  Big Grin 

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Parts that came in the kit are pretty straight forward, and seem to be of good quality. 1/4” plywood fins and centering rings, heavy eyebolt and rail buttons and a 38mm motor mount. This is the first Madcow kit I have purchased and am pleased with the quality of parts that are included. 
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I did purchase a couple extra parts to use in the build. A aero pack engine retainer and a Loc engine adapter so I can use some of my 29mm hardware for test flights. 
Stay tuned for construction updates!
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#2
So on to assembly, the top centering ring receives the eye bolt for shock cord attachment. I always add another nut and washer when I install these. 
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After a good sanding of the motor mount tube I tacked both centering rigs on the tube with some 2p10
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Then it’s time to set everything into place. A good coat of Rocket Poxy for the centering rings and some JB weld for the engine retainer. I always like to completely cover the exposed part of the aft centering ring with epoxy. Now time to let it cure before anymore assembly.
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I’m not used to working with motor tubes of this size lol this is my first 38mm power rocket and I will finally be able to test out the Loki 38/120 hardware I have. I realize that I can’t get a load for L1 certification with this case, but it should be a fun inexpensive way to play around in the 38mm rocket realm.
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#3
Next on the docket is install the motor mount in the body tube. For this I am using RoxetPoxy again for a great bond. 
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While waiting for that to dry, a little fin prep is in order. A good sanding and rounding over of the edges, and then I will shoot a couple coats of primer to fill in the grain. 
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Don’t make fun of my hillbilly high tech fin holders  Big Grin
Now for a bit of prep on the nosecone. This particular nosecone was in great shape when received, hardly any molding lines or imperfections. So a good sanding and it was ready for a shot of primer. 
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Now on to some body tube prep. A good sanding and I’m ready to shoot a few coats of primer to fill in the spirals of the tube. I will sand it down in the fin and fillet attachment area so I can get a good bond. 
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Well that’s about it for today. Hopefully get the fins attached here in the next couple days.
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#4
(04-25-2018, 07:04 PM)Hey,    It looks great ! Some suggestions. Its sometimes helps to assure that the CRs are level and perpendicular to the MMT, particularly when just using 2 CRs. In terms of mounting the rail buttons, its at times easier to do before the MMT is in place or at least before the aft CR is epoxied in-this allows you to get access to placement of a T nut or hexagonal nut inside the body tube to anchor the rail button screw to.  When you do the internals of the nose cone, you may want to consider a second AV bay there by using a coupler (epoxied in place) with an extension of 3 to 5 inches to slide into the upper body tube, A stepped bulkhead with eye bolt would be centered on the stepped bulk head. Classically, the bulkhead would be screwed into a centering ring with T nuts or alternatively epoxy threaded rod couplers to the inside lower coupler wall to screw the bulkhead to (see https://www.multitronix.com/uploads/3/1/...scheme.pdf  for some details).      Good luck and as stated above-it looks great!Fred, L2,kg4ygp  IndianaSteve Wrote: Next on the docket is install the motor mount in the body tube. For this I am using RoxetPoxy again for a great bond. 
[Image: AaMiLz.jpg]
While waiting for that to dry, a little fin prep is in order. A good sanding and rounding over of the edges, and then I will shoot a couple coats of primer to fill in the grain. 
[Image: K3wlfJ.jpg]
[Image: IK5BeG.jpg]
Don’t make fun of my hillbilly high tech fin holders  Big Grin
Now for a bit of prep on the nosecone. This particular nosecone was in great shape when received, hardly any molding lines or imperfections. So a good sanding and it was ready for a shot of primer. 
[Image: 9yByQg.jpg]
Now on to some body tube prep. A good sanding and I’m ready to shoot a few coats of primer to fill in the spirals of the tube. I will sand it down in the fin and fillet attachment area so I can get a good bond. 
[Image: 7ywaEM.jpg]
Well that’s about it for today. Hopefully get the fins attached here in the next couple days.
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#5
Thanks for the tips Fred!

Spending time in the fin jig tonight. It’s not pretty but it works well and was made from stuff in the workshop. Have to save money somewhere for motors  Big Grin
Anyways setting the fins tonight and tomorrow with some slow cure epoxy. As you can see in the pic, one of my fins in the kit had a bit of a defect so I had to put in a bit of spot filler. Won’t even be noticeable after paint. 
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Shouldn’t be long now and the Little John will be coming together!
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#6
Hi,

Looks good! I think you'll find that external fillets with rocket poxy are excellent. Internal fillets may be easier with an epoxy that flows more easily than the thick Rocket poxy such as West Systems & some add pulverized fiberglass (small amount) to the West Systems epoxy to add strength. Rocket poxy actually recommends no "additions."I just noted the nose cone is enclosed plastic. If you did want to make a nose cone AV-bay, then the most inferior section or base of the nose cone would need to be cut away. Obviously not necessary for Level 1 flights. I'm curious do you plan on motor ejection or altimeter/electric based ejection? Do you plan on dual deployment or single deployment? Finally, for recovery purposes are you planning to use a radio tracker or GPS or both?

Fred

You may want to consider using a CTI motor. There's a setup with your local provider that level test flyers get a free motor case if they fly using a CTI motor. I did that 3 years ago and got a free 6 grain case which I later used for my L2 flight also. So possibly check with your club's local motor provider and in this way you may save $50. By the way, CTI 38 mm and 54 mm motors are the simplist to put together with reloads, particularly in comparison to aerotech motors.

Fred.
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#7
(04-27-2018, 11:26 PM)FMarvinS Wrote: Hi,

 Looks good! I think you'll find that external fillets with rocket poxy are excellent. Internal fillets may be easier with an epoxy that flows more easily than the thick Rocket poxy such as West Systems & some add pulverized fiberglass (small amount) to the West Systems epoxy to add strength. Rocket poxy actually recommends no  "additions."I just noted the nose cone is enclosed plastic. If you did want to make a nose cone AV-bay, then the most inferior section or base of the nose cone would need to be cut away. Obviously not necessary for Level 1 flights. I'm curious do you plan on motor ejection or altimeter/electric based ejection? Do you plan on dual deployment or single deployment? Finally, for recovery purposes are you planning to use a radio tracker or GPS or both?

Fred

You may want to consider using a CTI motor. There's a setup with your local provider that level test flyers get a free motor case if they fly using a CTI motor. I did that 3 years ago and got a free 6 grain case which I later used for my L2 flight also. So possibly check with your club's local motor provider and in this way you may save $50. By the way, CTI 38 mm and 54 mm motors are the simplist to put together with reloads, particularly in comparison to aerotech motors.

Fred.
i will be using motor ejection on this rocket. I don’t plan on flying to terrible high with the level 1 flight, but I do have a chute release I can use to minimize recovery. 
I am going to be modifying the nose cone to add a adjustable nose weight system, and that will be able to be converted to an AV bay at a later date as well. 
I haven’t decided on a motor as of yet, I only have experience with Aerotech reloads at the moment but for test flight purposes I have a Loki 38/120 case and reloads that I will be giving a try. 
Thanks for the feedback! 
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#8
A little work on the build tonight. Finished attaching all the fins, and got the bottom 10” of the body tube foamed in with PML expanding foam. I like the way the expanding foam really locks everything together. I have used it on several builds with great success. 
Now it’s time for the task of laying on the external fillets. I’m using rocket poxy for these. This will be a pretty slow process over the next couple days being that the Rocket Poxy takes a while to set. So here is my view for the evening  Big Grin
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#9
Well been on hold for the past couple days after running out of Rocket Poxy. Wildman order should be here tomorrow, so should be back in business. Would like to get this rocket assembled and a coat of primer shot on it before Sunday’s club launch so I can give it a test flight.
Test flight will be on a Loki G94 Ice blue reload. Won’t be anything spectacular, just a nice easy test flight to prob 7-800ft and give me a chance to test out the Loki 38/120 hardware.
I’ve never used any Loki products, but am intrigued by some of their engines and look forward to testing them.
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#10
The fillets look real good!

Fred
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