Harpoon AGM-84A Model

[Austin]

Well, it's a good day here at the ole' workshop; yesterday my sheets of G10 fiberglass showed and today my order from PML arrived. So it's time to start on my Scratch 4" 33% Scale Harpoon!

The body tube is made of PML 4" Quantum tubing, which I had custom slotted and cut at the factory. They did their usual great job and, after taking measurements, they followed my cutting/slotting instructions to the tee! Hats off to the guys at PML.

This will be the first to be built in a series of 4" models I have designed and on the building board. I did check the WPAFB Museum website and they have one of every missile I have interest in on site, with the exception of this one. For some reason, it couldn't be that this is primarily a Navy missile, I am having a hard time finding pics for it so I can do scale decals. This will have to be an ongoing research item while the build continues.

I will begin tonite and try to start cutting out my fins from the G10. Updates will follow and my goal is to have it complete and ready to fly for our next Tripoli Mid-Ohio launch next month.

Carl

 

[rstaff3]

Shweeeet!

 

[Milo]

Impressive. Keep us posted on the progress.

 

[Austin]

Update:

Construction has begun; I cut the 38mm motor mount tube to 23.75", then measured and glued the first centering ring, which will be the lower of two rings for the center fins. Both sets of fins will be sandwiched between centering rings.

Next, we cut out the fins from the RockSim pattern I printed out from the design. Using a Dremel, asbestos cutting wheel and a vacumn to pull in the dust while we cut, all four upper fins and four lower fins were cut with ease from the G10 sheeting. They were final sanded on my table sander and now fit the slots well. After cutting my own G10 fins, I highly recommend this to anyone who wishes to scratch build; it will save you a fortune over pre-cut fins and are very easy and fast to make.

The four inch coupler was cut to a length of 7" and edges were sanded. Finally, I measured the 1/2" thick by six inch centering ring, which will extend past the rear of the body tube as a boattail. It was reduced to 4" in diameter, so it would fit flush with the outside of the body tube.

With all the parts cut, sanded and fitted, I am at the stage of completion for "kitting" the model, so construction will begin next and should go quickly.

 

[Austin]

A centering ring was mounted to the motor mount tube and it was installed in the body tube after roughing it up with sandpaper. This CR sits just below the slots for the center fins. A second CR was installed just above the lower fin slots. Fin edges were rounded and surfaces were roughed up and the lower fins were glued in place to the motor mount and upper CR. Also, the lower fins were glassed from the motor mount, up the inside of each fin and across the inside of the body tube area. In addition, the lower centering ring was installed flush with the body tube and against the bottom of the lower fins. Finally, the lower transition was sanded to angle the bottom edge for the "transition" look.

Blind nuts will be installed next in the transition 1/2" thick plywood base, then it will be epoxied to the bottom of the body tube and motor mount.

That is all for now

 

[Austin]

Last nite:

I worked on the ply 1/2" thick tail transition piece. 3 holes were drilled through it to accept the 8/32 sized bolts for the PML motor retainer. I used a 1/2" drill bit to open a recess in the top side of the transition, then carve it out using a dremel and small sanding tube so the blind nuts would sit recessed inside this "well". This was necessary so the piece could be glued flush to the bottom CR on the model. Next, I placed some glue inside the recess and installed the three blind nuts, then tested for a flush fit. Finally, the blind nut threads were filled with wax, then the excess wax was shaved flush and I epoxied the transition to the bottom of the rocket and motor mount.

Upper fins were next; each canard fin was glued to the motor mount and lower centering ring. I also took the final centering ring, the one that would fit on top of the center fins and drilled two holes, then mounted the Stainless Steel 3" wide U-Bolt for the shock cord.


Tonite:

I glassed each canard fin inside to the motor mount and inside body tube, then glued in the last centering ring with the U-Bolt as a top cap to the center fins. The coupler was installed next, followed by the upper section of body tube. I ran masking tape around the seam to help keep both upper an lower body tubes in alignment with eachother until the glue set. I have seen where a coupler has some play and can leave the joint a bit "out of round", which leaves a little overlap between the tubes. Using several wraps of masking tape kept it in alignment and the tape easily pulled off once the glue has set. The coupler adds strength to the centering ring since it is holding the ring down atop the center fins. This method was used to insure it had a solid anchor since it has to handle the stress of deployment.

Once everything had dried, I started glassing the lower fins. At this time, one of four sides is glassed. While the epoxy was still curing for the cloth, I cut the lower 1/2" launch lug to a length of 2 1/2", then epoxied it between the lower fins, 1" from the body tube bottom.

Nuf for now...more to come...

Carl

 

[PGerringer]

Wonderful report, Carl. I feel like I'm right there with ya. You are taking pictures right?

 

[Austin]

Yesterday, I finished fiberglassing the fins, then added fillets to the upper canard fins and mounted the upper launch lug. My supply of epoxy ran out, so I had to stop; I am going shopping for more epoxy today during lunch.

Also, I did some housecleaning after I ran out of epoxy; the shelves were in disarray and were driving me crazy!

This will be the only reply that will have pictures and I will add more to the bottom of the list as time goes on, so check back often.

Here they are:

Pics as of 12/02/2001:

<a href="reviews/harpoon/1.jpg">The Right Stuff<br></a>
<a href="reviews/harpoon/2.jpg">Parts Pic 2<br></a>
<a href="reviews/harpoon/3.jpg">Parts Pic 3<br></a>
<a href="reviews/harpoon/4.jpg">Motor Mount Cut<br></a>
<a href="reviews/harpoon/5.jpg">Fitting Lower Rings<br></a>
<a href="reviews/harpoon/6.jpg">Inserting the Canard Fin Lower Ring<br></a>
<a href="reviews/harpoon/7.jpg">Homemade Marker<br></a>
<a href="reviews/harpoon/8.jpg">Marking the Lower Canard Fin Ring’s Position<br></a>
<a href="reviews/harpoon/9.jpg">Marked Motor Tube<br></a>
<a href="reviews/harpoon/a.jpg">First Centering Ring Glued<br></a>
<a href="reviews/harpoon/b.jpg">Marking Transition Ring Size<br></a>
<a href="reviews/harpoon/c.jpg">Marked Transition<br></a>
<a href="reviews/harpoon/d.jpg">Close-up<br></a>
<a href="reviews/harpoon/e.jpg">Transition Ring Ready to Cut<br></a>
<a href="reviews/harpoon/f.jpg">Test Fitting Motor Mount with Ring<br></a>
<a href="reviews/harpoon/g.jpg">Drawing Fins from Pattern<br></a>
<a href="reviews/harpoon/h.jpg">Fin Drawn<br></a>
<a href="reviews/harpoon/i.jpg">Time to Cut<br></a>
<a href="reviews/harpoon/j.jpg">Cutting Pic 2<br></a>
<a href="reviews/harpoon/k.jpg">Sanding the Edges<br></a>
<a href="reviews/harpoon/l.jpg">Two Canard Fins<br></a>
<a href="reviews/harpoon/m.jpg">Lower Fin Pattern and Finished Fin<br></a>
<a href="reviews/harpoon/n.jpg">Canard Fins Made<br></a>
<a href="reviews/harpoon/o.jpg">Fins Complete 1<br></a>
<a href="reviews/harpoon/p.jpg">Fins Complete 2<br></a>
<a href="reviews/harpoon/q.jpg">The Line-up of Parts<br></a>
<a href="reviews/harpoon/r.jpg">Motor Mount Ring Glued in From Top<br></a>
<a href="reviews/harpoon/s.jpg">Inside Tube Roughed Up<br></a>
<a href="reviews/harpoon/t.jpg">Lower Fins Glued<br></a>
<a href="reviews/harpoon/u.jpg">Lower Fins Part 2<br></a>
<a href="reviews/harpoon/v.jpg">Lower Fins Part 3<br></a>
<a href="reviews/harpoon/w.jpg">Rear View<br></a>
<a href="reviews/harpoon/x.jpg">Beveling Transition Ring<br></a>
<a href="reviews/harpoon/y.jpg">The Results<br></a>
<a href="reviews/harpoon/z.jpg">Beveled Ring 2<br></a>
<a href="reviews/harpoon/z1.jpg">Holes Drilled for 8/32 Retainer Bolts<br></a>
<a href="reviews/harpoon/z2.jpg">Blind Nuts Inserted Flush<br></a>
<a href="reviews/harpoon/z3.jpg">Gluing on the Transition<br></a>
<a href="reviews/harpoon/z4.jpg">Upper Centering Ring with Stainless U-Bolt<br></a>
<a href="reviews/harpoon/z5.jpg">Canard Fin Gluing<br></a>
<a href="reviews/harpoon/z6.jpg">Preparing to Glass<br></a>
<a href="reviews/harpoon/z7.jpg">Lower Fins Glassed…Lower Launch Lug Glued<br></a>
<a href="reviews/harpoon/zabefore.jpg">Break Time…Time to Clean the Shelves…Before Pic<br></a>
<a href="reviews/harpoon/zafter.jpg">Shelves…After Pic<br></a>



Pics as of 12/03/2001:


<a href="reviews/harpoon/z8.jpg">View down the Tube<br></a><a href="reviews/harpoon/z9.jpg"><br>View of U-Bolt Installed<br></a>
<a href="reviews/harpoon/za.jpg">Canard Fin Fillets<br></a>
<a href="reviews/harpoon/zb.jpg">Lower Fin Fillets<br></a>
<a href="reviews/harpoon/zc.jpg">Finished Build Full Photo<br></a>



Pics as of 12/04/2001:


<a href="reviews/harpoon/zd.jpg">Ply Tail Glazed</a>
<a href="reviews/harpoon/ze.jpg"><br>Ply Tail Glazed 2<br></a>
<a href="reviews/harpoon/zf.jpg">Canard Fillets Sanded<br></a>
<a href="reviews/harpoon/zg.jpg">Lower Fin Before Sanding<br></a>
<a href="reviews/harpoon/zh.jpg">Body Tube Seam<br></a>
<a href="reviews/harpoon/zi.jpg">Nose Cone Top View<br></a>
<a href="reviews/harpoon/zj.jpg">Nose Cone Side View<br></a>



Pics as of 12/05/2001:


<a href="reviews/harpoon/zg.jpg">Fins Before Sanding</a>
<a href="reviews/harpoon/zk.jpg"><br>Fins After Sanding<br></a>
<a href="reviews/harpoon/zl.jpg">Ready for Primer<br></a>
<a href="reviews/harpoon/zm.jpg">Holes drilled for Retainer<br></a>
<a href="reviews/harpoon/zn.jpg">White Primer With Gray<br></a>
<a href="reviews/harpoon/zo.jpg">Gray Primer After Filling<br></a>
<a href="reviews/harpoon/zp.jpg">White Primer Ready to Wetsand<br></a>



Pics as of 12/06/2001:


<a href="reviews/harpoon/zq.jpg">Finished Nosecone</a>
<a href="reviews/harpoon/zr.jpg"><br>Finished Painting<br></a>
<a href="reviews/harpoon/zs.jpg">Another Pic, Paint Complete<br></a>

 

[MarkABrown]

Carl,
Man I was with you until the shelf before and after pic! OMG! Martha Stewart's got nothing on you!

 

[Milo]

Impressive pictures. Can't wait to see the finished product.

uh... what exactly is "denatured" alcohol.

 

[Austin]

Milo,

Denatured Alcohol is made from wood, rather than grain, and is nearly 100% pure. It works great on removing dripped, sticky epoxy from parts and hands and it doesn't attack the plastic Quantum body tubes like Acetone does. It also makes an ok paint remover, although Acetone does do better in this area.

Mark...I am kind of a neatness nut, so the shelves look more to my suiting now...good one about Martha though, I LMAO!

Now, a test...let's see who was paying attention...how many cans of primer do I have on hand?

...this is a test...

Cya

 

[MarkABrown]

I see 9 cans of primer.

 

[Milo]

Only 9? Stock is getting a little low isn't it Carl?

 

[kgholloway]

Carl,

I think you have your alcohols mixed up.

Denatured Alcohol (C2H5OH) is actually grain alcohol, the same as in whisky, with one or more chemicals added to make it undrinkable.

Wood Alcohol (CH3OH) is a poisonous alcohol that is not commonly found in stores. The most common form of alcohol found is Isopropyl Alcohol ( (CH3)2CHOH ) which is sold as "Rubbing Alcohol".

I've found that the best alcohol for cleaning up epoxy is 99% Denatured Alcohol. It can be purchased from some paint stores as it is used as a thinner for shellac. Alternately you can make it from 70% or 90% alcohol by removing the water.

To "dry" alcohol obtain one or two pounds of Copper Sulfate (CuSO4) crystals. Place the crystals in the bottom of an open baking dish and bake in a 250 degree oven until all of the crystals turn white. This is known as "anhydrous copper sulfate" and it absorbs water like a sponge. Take a bottle of 70% or 90% Denatured Alcohol and slowly add the anhydrous crystals to it. As the crystals "suck" the water out of the alcohol they will turn blue again. Keep adding crystals until they stop turning blue. At this point cap the container tightly because the alcohol is so "dry" it will absorb water from the humidity in the air!

Ken Holloway, NAR #78336, L-1

 

[Austin]

My stock of primer...low??? Heaven forbid!

KG, yes you were right, I did have them mixed up. BTW...great idea on drying out alcohol !!!

Update:

New pics posted.

Last nite I finished fillets for the lower fins. Also, I added fillets for the two launch lugs. The rocket build is complete and tonite I have begun sanding fillets and fins for primer. Lower fillets are done so far...more to come.

 

[Austin]

Update for 12-4:

New Pics Posted.

The upper fillet sanding was completed. In addition, the seam was sanded smooth and lower fillets were sanded, but the cloth edge still needs blended to the body tube. Also, the bottom of the boattail plywood was glazed with epoxy.

I did some work on the Nosecone; if you all have never had the pleasure of using the RGM Nosecones, you are really missing out! The quality is fantastic with a SEAMLESS design, yes, I said seamless. It was like a rocketeers dream come true! The nosecone is made from resin and cloth and is yellow in color, similar to the resin model airplane and boat kits you can buy. The quality is excellent, with a good fit at the base, a molded-in U-Bolt and ultra smooth finish, right out of the box. They are to date the only "round" Nosecone I could find in the 4" version. As a final FYI, Ross at Magnum told me that the gentleman at RGM lays up all these cones one at a time, by hand! With a price of $29.95, they are about $10 more than a plastic ogive nosecone, but you get what you pay for and it's worth it!

Back to the build; the nosecone was lightly sanded and washed to remove any release agents, then one coat of primer was applied, which came out nice. No problems were found with the primer sticking to this resin Nosecone.

More tomorrow...

 

[Austin]

Updated Pics posted.

The glassing in the lower fin area was sanded and blended using a dremel power sander, then touched up by hand with 100 grit sandpaper. I left a before and after pic next to eachother in the new pics section to see the difference. Plugs were inserted into the lugs so they would not get painted inside, then the holes for the motor retainer were re-drilled out and blind nuts were tapped with an 8/32 tap to remove the wax used to seal the threads from epoxy.

Next, 3 coats of white Krylon primer were applied to the body, followed by two coats of gray Krylon primer. Pinholes were filled next, then sanded with 220 grit sandpaper. Two more coats of gray primer were applied, followed by 3 coats of white primer. I am letting the body tube dry overnite and will wetsand it tomorrow, then apply more primer if necessary and the colors. Finally, the nosecone was given about 6 coats of primer, then wetsanded with 320 grit wet/dry sandpaper; 3 more coats of white primer were applied to the nosecone and left to dry overnite.

That is all for now.

 

[Austin]

A few more pics were added.

The model was wetsanded with 400 grit wet//dry paper, then 600 grit. I painted the Nosecone first, with 4 coats of Krylon Glossy White spray paint. Next, the body tube was painted, also with four coats. They are both dry, but I am letting it set overnite before painting the stripes. In the interum, I am working on some scale decals for the Harpoon, but need pics...I don't have any good pics of the lettering for different sections.

I also took the chance to glosscoat the Small Endeavour. I sprayed it with Krylon Clear Gloss over the Rustoleum Copper paint job and there were no compatability problems. I named the kit <i>"Full Metal Jacket"</i> ... which seems appropriate for the color.

Cya

 

[PGerringer]

That is one beautiful rocket!!! Keep the updates coming man...

 

[Austin]

The Harpoon was weighed today at our first HPR launch ever for our Cincinnati NAR club. I almost fell over when I saw, but knew it was going to be heavy, as I added most of the ballast in birdshot that Ken Parker gave me when I was in NC this past summer. Ken, I need more, almost out!!!

Well, remember this is an HPR kit with huge fillets, glassing and a higher CP requiring more ballast in the nosecone. This is a 4" model that only stands 47" tall and weighed...

6lbs 7.8oz without motor!!!!!

I almost died...going to have to re-do all my sims to see if it can handle an I211 because, even though she isn't painted, she IS flying tomorrow at our HPR Launch, which is a two day event. It will be like flying a heavy torpedo, which is what it represents anyway, so what the heck.

Carl...still stunned!

 

[KenParker]

WOW !!! Carl - I think you win the "it's definitely over-built" award for the year !!!

Almost 7 lbs.... Holy schnikies....

 

[Austin]

I am going to try to get the Harpoon out of the tree tonite, using a ball tied to some fishline for leader, which will be used to pull some clothesline up and around the model. It's up around 35-40 feet so wish me luck. I will have about 1/2 hour of sunlight so it's not too promising and if I can't get it, my bow will come with me to work tomorrow and I will try at lunch time. Fortunately, I work only about 10 minutes away from the field. Kent "The Intimidator" could help by telling me how he tied the string to the rear of the arrow...(hint, hint Ken...I know who the real hero was and know you did the setup...input please). I used to be a pretty good shot, so we will see tomorrow if this doesn't work out tonite.

Report at 7pm...

Babe Ruth I am not, but what the heck

 

[KenParker]

Yes, Carl, you are right - Kent did not do the setup of the arrow. And, I did not do it by myself, either. Milo actually was the major input to that effort (as he had a lot of experience from when he was helping Phil try to get his rocket), and he and I collaborated on setting up the arrows for Kent.

After several experiments, we found that the best way was one wrap around the rear of the shaft, just behind the feathers and in front of the notch, and a granny knot, and then two or three wraps of masking tape around that.

When you shoot the arrow, you should have the line in a nice loose pile on the ground, making sure that the line feeds up to the arrow on the side away from the bow.

Carl, if I know you, you probably have a 60, 70, or 80 pound compound bow (MORE POWER, grunt, grunt). That was Phil's problem - his bow was way too powerful, and he was launching stuff into orbit. We were successful because Kent's bow is a beginners bow, and it is probably just around 30-35 lbs.

Oh, and by the way..... Phil supplied us with some cheap but heavy wooden arrows to use. I think he got them at WalMart. It is IMPORTANT to have heavy arrows for two reasons:
> it helps prevent them from going into orbit
> you need the weight so that it will pull the line down

Good luck, kemosabe. (That's what Tonto used to say to the Lone Ranger all the time. Now that I'm all grown up, I'm pretty sure the literal translation of 'kemosabe' is "White man who hide behind little black mask is major chicken ****.")

 

[Austin]

Thanks Ken, a good answer for a dissapointing day. I went to the site and tried the ball thing, but they were tennis balls as they were out of baseballs at the store...yea, that's what I though too. I was short in my throw by 15', probably because I had to stand so far away for an opening. I tried the bolo method, which got the height, but no accuracy.

So, it's bow time. I think I mentioned that I have an old Ben Pearson 45lb Recurve bow, so I can easily adjust the tension. The compound bow and crossbow will stay home. I don't have heavy arrows, but will try it with some of my Easton 2117's and see how it does. I may even pour some lead and epoxy in a one if I have time tonite.

After observing the rocket, I swear it has shifted out a bit, as if the parachute is sliding off the top of the branch. I can only hope I show up and it's on the ground tomorrow.

Will keep you all posted.

 

[KenParker]

C'mon, Tulanko.... don't keep us in suspense. Didja get the Harpoon out of the tree today or not? Huh? Didja? Huh?

 

[Austin]

No...couldn't try due to Car problems...going tomorrow in the am before work, then at lunch if need be.

 

[Milo]

Did I miss something? This thread has been talking about the build out of the Harpoon. All of the sudden it changes to a recovery effort of a Harpoon. What gives?

 

[KenParker]

Milo: Yeah.... you've missed a lot. Go to the EVENTS section and read about Carl's two day launch this weekend. Then you'll understand what is going on with the last couple of posts to this thread.

Carl: Sorry to hear about your car problems. Was this your old ride or your parent's loaner ride? I hope it is just your old ride. I'd hate to think you were now also having problems with your parents loaner ride.

Anyway, good luck on both your car problems and the Harpoon recovery effort. Keep us posted.

 

[PGerringer]

Wake up Milo!

Lets see, if Carl killed his car and now he has killed his loaner. Hmmm, sounds like operator error to me...

 

[Dr. Don]

Hey there Ken!
What is the correct pronounciation of "schnikies" ? Is that the
proper term for an overbuilt rocket hanging from a tree?
William Tell to the rescue!!!!! DR DON