TLP 2.6" MIM-23B HAWK Build

[El Phantasmo]

It has begun!

The Launch Pad 2.6" MIM23-B HAWK (Homing All the Way Killer)

Obligatory bag and parts shot (only stock parts shown, doesn't include extras or substitutions).

 

[El Phantasmo]

Motor mount

I had a tube that was just larger than the stock motor mount tube. The stock motor mount, to me, felt thin and likely to give in to heat fatigue. So, I cut down the larger tube to fit between the 2 centering rings, and epoxied over the stock motor tube. I added a motor retainer from the Rocketarium.com. All of the motor mount parts are affixed with regular JB Weld. "Why everything with JB Weld?" you ask. The small amount I mixed for the motor retainer was enough to epoxy all the other parts for the motor mount assembly. I completely left out the stock motor hook. The 2 piece motor retainer provides retention in both fore and aft directions.

EDIT: If you're going to use a heat shield of some sort (aluminum cans are cheap and easy to come by), here is where you should start! Cut out a disk the diameter of the aft centering ring with the appropriately sized center hole. Epoxy the head shield to the aft centering before putting the rest of the assembly together. I didn't think to do this, so I'll have to make 2 haves and it'll be more fiddly. See post 14.

 

[El Phantasmo]

Both of the paper parts were my first attempt on each. I made one more of each, but they were no better. I used 110# card stock. I used super glue on the tabs. Then I saturated them with finishing epoxy. First, I did the tail cone, then the nosecone. Rather than drill a small hole (per the instructions) I decided I was a Mohel. :y: Who's next?

 

[El Phantasmo]

Here's the tail cone. Rather than use the extended template tab, I cut it off. I cut a slightly wider strip of card stock and super glued it on the inside of one side, then to the inside of the other.

 

[El Phantasmo]

Here's the tail cone assembly with the, still wet, epoxy coated paper tail cone (3rd and 4th pictures). I used Titebond I wood glue, to glue the centering rings to the tube, and I allowed the bit of epoxy I smeared on the fore inside of the tail cone to adhere to the lower centering. I, then, gently tamped down the aft centering ring with a ball point pen, to seat it in the tail cone. The second photo, is a dry fit of the parts and markings for reassembly. I should have glued the aft centering ring to the tube first, dry fit the paper tail cone and then cover the tail cone in finishing epoxy. C'est la vie... After the tail cone assembly and motor assembly fully dry, they'll be glued together. Then, I'll cut and epoxy a thin piece of aluminum (beer/soda can) to the inside of the tail for heat shielding.

 

[El Phantasmo]

If you've build a rocket before, you know what I did here. I replaced the thin, short stock tube coupler with a 4" red tube coupler. I used Titebond I to glue them together.

 

[Stymye]

cool yet another tlp build , If I had known I would have dropped a nice thermal rider in your package.

 

[El Phantasmo]

Thanks, but I already bought an 18" Skyward for it. More assembly tomorrow evening and hopefully some more pictures.

 

[El Phantasmo]

After dry fitting the motor mount into the tail cone assembly, I found the aft centering ring on the motor mount was just too bit to big; a little sanding quickly took care of it. I then made some markings inside the tail cone assembly, so glue could be applied in the proper spot. I put glue at the fore marking, slid the motor mount in with enough space to apply glue using a thin piece of balsa to the aft marking and finishing inserting the motor mount.

 

[El Phantasmo]

The aft centering, that sits at the fore of the paper tail cone, sits a little low as compared to the instructions. So, I dampened the area and half filled it with Gorilla glue. I tied the kevlar shock cord under the fore most centering of the tail cone assembly and fed the shock cord through the body tube. I dampened the bottom 1/4" of the main body tube, for the Gorilla glue. Then, I applied wood glue to inside of the main body tube, about 2" in. I then slid the complete tail assembly into the main body tube, making sure the main body tube sits down on the tail cone and is at a right angle, on 3 sides, to my working surface. Last, I squeezed a few drops of water and some Gorilla glue down into the nose cone.

 

[El Phantasmo]

The Gorilla glue, I put in the channel of the fore end of the tail cone, foamed up nicely. It expanded into the gap between the paper tail cone and the tail cone tube very well. The paper above the centering and below the main body tube doesn't yield to moderate pressure. Only a slight bit of glue foamed up and made about a 3/8" long ridge at the tail cone body cone joint.

The Gorilla glue in the nosecone, also foamed up as expected. The nosecone hat is pretty solid now.

I'll post pictures later.

EDIT: Pictures Added

 

[El Phantasmo]

I made a heat shield from an aluminum can. I used πd to find the length of the strip I needed to cut, since it's a cylinder not a cone. I punctured the can with an exacto knife on each end to cut the ends off. A regular pair of "paper" scissors worked fine. I used a ruler and pen to measure the strip I needed. I sanded and scored the printed surface of the can for better adhesion. I lightly screwed on the motor retainer aft closure, to prevent epoxy from getting on the threads. Next, I mixed JB Weld and smeared it around the inside of the tail cone/motor mount. I placed a thin strip of metal in first, to cover the small gap from cutting the heat shield about 1/16" too short. I then rolled the heat shield to be a little bigger than the motor retainer. I set it down the center and gently relaxed my grip to let the coil expand into place, while trying to make the edges sit over the thin strip I already placed. A little pressing and wiping up is all I can do until the epoxy cures. I didn't use any clamps or anything. The heat shield barely sticks out from the aft end; once the epoxy cures, I'll sand it flush and smooth.

 

[Stymye]

oh very nice !

 

[El Phantasmo]

:bang: I didn't think to use a heat shield or epoxy on the fiber centering ring... I'll fix that later.

 

[sodmeister]

:bang: I didn't think to use a heat shield or epoxy on the fiber centering ring... I'll fix that later.

I always do the aluminum can thing ,and just brush on some JB weld or 15/5 min epoxy (JB is the better choice)

Paul t

 

[El Phantasmo]

I haven't had such large, thin (1/8"), single pieces of wood on a rocket before. Is Bondo spot putty (the dried blood version) likely to cause the wood to warp? How can I prevent the fins from warping if I air foil them? I'd rather not paper these; I've added enough weight to the aft end as is. I may just experiment and see.

Thanks

 

[El Phantasmo]

Here's the heat shield I should have done much earlier. I used a compass to score the aluminum, then I cut it out with scissors. They were a little tight, but some snipping fixed that, mostly. I used some aluminum foil and a rubber band to protect the treads of the motor retainer. Yes, more JB Weld. One of the halves bowed up a little in a few places, so some narrow objects and clamps were needed.

 

[luke strawwalker]

I haven't had such large, thin (1/8"), single pieces of wood on a rocket before. Is Bondo spot putty (the dried blood version) likely to cause the wood to warp? How can I prevent the fins from warping if I air foil them? I'd rather not paper these; I've added enough weight to the aft end as is. I may just experiment and see.

Thanks

Bondo spot putty is basically VERY VERY THICK primer... it uses just enough lacquer thinner to make it a paste, and the rest is primer solids. SO I don't think it should warp anything... the balsa will absorb it, but it shouldn't make the wood swell, which is what causes stuff to warp. The lacquer thinner carrier should outgas very quickly.

Later! OL JR

 

[Stymye]

wouldn't papering be much stronger and lighter ?
is filling balsa fins with bondo a common practice these days ?

 

[luke strawwalker]

wouldn't papering be much stronger and lighter ?
is filling balsa fins with bondo a common practice these days ?

Yeah, personally I'd do it with papering with printer paper and white glue, BUT it does add SOME weight and with TLP kits, ya gotta be REAL careful about the effects on the CG. Filling with Bondo Spot Putty and then sanding 99% of it off would probably be lighter, but you're right... it adds ZERO strength to the fins...

If one wants ultimate performance/minimal weight addition and doesn't care about the strengthening effects of papering the fins, then Hobbylite filler is probably the best bet... (stuff that feels like the can is empty even though it's full...)

Personally I like the added strength and durability of papered fins and don't mind adding a bit of noseweight to bring everything back in line, but that's just me... It's a personal judgment call...

Later! OL JR

 

[El Phantasmo]

Bondo spot putty is basically VERY VERY THICK primer... it uses just enough lacquer thinner to make it a paste, and the rest is primer solids. SO I don't think it should warp anything... the balsa will absorb it, but it shouldn't make the wood swell, which is what causes stuff to warp. The lacquer thinner carrier should outgas very quickly.

Later! OL JR

That's what I thought. The putty off gasses so quickly and there's so little carrier the balsa isn't likely to warp. No paper this time.

Thanks

 

[El Phantasmo]

Standard 1/8" hard balsa, just the main fixed fin thus far. I simply used a sharp #11 blade to cut it. We'll see how the air foil looks once it's painted; it's not a very dramatic air foil. The aft portion of the fin is flat, no taper; while, the fore and outer portion is tapered. I used some wood paint stir sticks to make sure I don't sand past the air foil line. After I sanded the air foil, I soaked the fins with super thin CA and re-sanded until smooth.

 

[El Phantasmo]

Typical fill, sand repeat. One or two more times.

 

[El Phantasmo]

I've made some progress since February 23rd. I misplaced a camera with pictures, but it was found. Fins are on, most filling and sanding is done, did some late stage modifications (a little messy), working on the aft ends of the "wire guides" to make them look more realistic. I'll post some pictures later, after work.

 

[El Phantasmo]

Here's some fin stuff with spot putty and my "custom fin alignment jig." I used 60 minute epoxy (not the finishing epoxy shown as part of my "jig") on the fins because some spots on the root edges took some super glue. Prior to this, I used more spot putty to hide the paper tail and nosecone transition seams. I modified the "steering" fins and aft main fins to look more realistic; they're not all exactly the same, but they're close enough for me. All the fins were soaked with thin CA.

 

[El Phantasmo]

Here's the aft end of the "wire guide" that goes from square to round, on which I've been working. It's made from 0.016" thick aluminum, I purchased from Hobby Lobby. It'll get some bondo to pretty it up, after it's epoxied down. The other one that stays square is a bit more tricky for me, not sure why.

 

[gdjsky01]

I have not read every post yet... I'll try and catch up... but watch the CG!! The CP on my 1.6 inch Hawk was only 13 inches from front! Basically 1/4 of the back from the front of the fin root. ...Heavy Tail Hawks are a :no: :no:

 

[El Phantasmo]

I have not read every post yet... I'll try and catch up... but watch the CG!! The CP on my 1.6 inch Hawk was only 13 inches from front! Basically 1/4 of the back from the front of the fin root. ...Heavy Tail Hawks are a :no: :no:

I'm well aware of that. I couldn't manage to form card stock to have a nice square to round transition. The aluminum is very thin and weighs next to nothing, if you look at it wrong it bends. I'll manage the overall weight with some nose weight in the end. If I remember, the OpenRocket file I have (original is a RockSim file), with modifications as best as I could envision, has a surprising margin of stability, given the reported stability issues with TLP kits; but I'll certainly recheck CP and CG and make proper adjustments. There's no motor hook or engine block, so I can also add a little extra umph if needed. All that's left for construction is the balsa "wire guides." Then, it's time to paint.

 

[El Phantasmo]

Filler then primer, wash, rinse and repeat. No pictures in that state, yet. Drilled holes and fitted 1010 rail buttons.

I'm waiting on a spray paint order. Sometimes I'm a bit of a color Nazi. Not so much to match real world colors, simply a color that makes me go "ooouuuuu" or "that's it." Consequently, my OD green turned into Montana Gold "NATO." Now what "black" do I want to use for the lettering?

 

[Stymye]

Now what "black" do I want to use for the lettering?

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