Aim-4 G Super Falcon Build

[Bruiser]

Some of you may have seen my GAR-1 build going on over in the "Low Power" forum. I mentioned in there that I have designed several Falcon models in OR and was having trouble deciding which to build so I decided to start at the beginning of the Falcon program with the first build. This build is of the last AIM-4 model, the "G". There are some well know spin-offs of the Falcon program, notably the AIM-54 Phoenix and the AGM-65 Maverick, but those are stories and perhaps builds for another day.


My build is going to use most of the parts from a Super Big Bertha kit. Even though I won't be using the parachute or the fins, it's more cost effective than buying everything separately.

I started with filling the spirals in the body tube then moved on to the motor mount. I did use the cardboard centering rings because they will be plenty strong when combined with the thru the wall fins. I did cut slot in another of the centering rings so that both the forward and aft fin tabs would index into the rings.

I like to start off by gluing the forward ring into the body tube first. The tape on the motor tube is there so I can use the motor tube to push the centering ring in. At this point the centering is not glued to the tube. The other centering is not glued either, it's just there the keep the tube aligned.


I use a long stick to smear the glue around inside the body tube then I push the forward centering in with the motor tube and leave it to dry. Once dry I remove the motor mount


Next step is to glue the mid centering ring to the motor tube and let it dry. I also chose this time to cut the slots for the fins.


Once the centering ring is dry on the motor mount it is time to install them into the body tube. So once again I'll use something long to smear the glue inside the body tube. I also run glue around the outside of the motor tube where it slides into the forward centering ring. Then it is time to slide it into the body tube and forward centering ring. With glue there's not much time to mess around so line it up with the fins slots and get the depth adjusted right away.


Last thing (or so I thought) was installing the aft centering ring. Fairly simple to run a bead of glue inside the body tube and the motor mount then slide the centering ring in place while setting the slots to line up with the fin slots and setting it to the right depth. Mine came out looking like this.


Let me mention fitment. Before putting glue to anything make sure it will fit where it needs to go. When I did this step I found that the centering rings on this kit are very loose in the body tube and very tight around the motor tube. I sanded out the inside of the centering rings for a nice fit but I couldn't do anything for the looseness in the body tube. That created a problem because my nice fillets "leaked on thru to the other side" and I had to go back and redo them. It also made it take longer for the glue to dry. You can see the gap in the last picture

I was happy with the progress and I broke for lunch. I also wanted to go out and get a screw eye and hardware to install in the laundry shelf. While out driving I realized that I forgot about the aft rail button mount. It should have gone between the mid and aft centering rings. I have a fix in mind but I also just remembered I did not get around to ordering blind nuts...

-Bob

 

[Bruiser]

I ordered the blind nuts and they are supposed to arrive tomorrow.

In the meanwhile I got all the plywood fins cut out. I did not have a piece of ply large enough to cut all four fins out of so they came from two different pieces. Two from one, two from the other. Two fins from one piece of ply weigh almost twice as much as the other two so I will have to be sure to put the heavy fins opposite each other when they are glued on.


I'm deciding if I want to quasi-glass the body tubes on this rocket. I don't think I have done that on a BT-80 rocket yet. It's make the tube super smooth and a but more rigid but it's a lot more work and I'm not sure if a nylon will be tight against it...

That's it for today. On hold for blind nuts now
-Bob

 

[Bruiser]

The blind nuts came in today so I got busy but first a little comparison. Both of these
are 8-32 blind nuts. Dubro brand on the left and the nuts from Amazon on the right.


I epoxied them in to the plywood mounts and installed the upper into the combination
coupler/laundry shelf/ recovery harness mount/upper rail button attachment assembly


Then I had a little retro fitting to do for the lower rail button mount. I used my x-acto knife to cut
a section out of the lower centering ring so I could slide the mount into place. I stabbed the plywood
mount with my x-acto knife so I could guide it into the body tube and I installed the rail button and
screw to hold it in place while it cured.


I also epoxied the coupler and joined the two body tubes together. The joint wasn't too smooth so
I applied some thinned CWF and am waiting for it to dry. That's 28.4 inches of body tube and with the 4 inch
nose cone the rocket will be 32.4 inches tall.


-Bob

 

[burkefj]

You can get weld nuts, like t nuts but no prongs, just a flange, you can bend the flange slightly with pliers so it conforms almost flush with inside of airframe, no ply required, a bit lighter too.

 

[Bruiser]

Hey Frank,

I've used weld nuts before but I have yet to find any in the 8-32 size that have the holes drilled in the flanges for the glue to grab. I find it a bit of a pain to drill them myself. I glued them with the barrel inside the body tube and I worry the regular base style might pop off so I like the extra "grip" the holes provide.

I know Apogee sells rail buttons that come with weld nuts and the weld nuts are installed so the barrel sticks out from the body and the rail button actually slides over the barrel. I purchase rail buttons from railbuttons.com and they do not fit over the barrel of a weld nut.

-Bob

 

[burkefj]

Hey Frank,

I've used weld nuts before but I have yet to find any in the 8-32 size that have the holes drilled in the flanges for the glue to grab. I find it a bit of a pain to drill them myself. I glued them with the barrel inside the body tube and I worry the regular base style might pop off so I like the extra "grip" the holes provide.

I know Apogee sells rail buttons that come with weld nuts and the weld nuts are installed so the barrel sticks out from the body and the rail button actually slides over the barrel. I purchase rail buttons from railbuttons.com and they do not fit over the barrel of a weld nut.

-Bob

I use 6x32 which the shaft fits inside the rail buttons, and the 6x32 screws are just fine. I don't find a need for the holes, especially in something as light as BT-80 but we all have our own preferences of course. The railbuttons.com rail buttons do fit over a 6x32 barrel.

 

[mh9162013]

I like to start off by gluing the forward ring into the body tube first. The tape on the motor tube is there so I can use the motor tube to push the centering ring in. At this point the centering is not glued to the tube. The other centering is not glued either, it's just there the keep the tube aligned.

You discuss using this MMT installation method and it's fascinating. Is the reason for doing that to provide an opportunity to provide a second fillet to the front/top centering ring? So instead of just one fillet in the front/top of that ring it now has two, just like the back/bottom centering ring.

 

[Bruiser]

If the barrels are sticking out from the body tube I'd be more comfortable without having the holes in the well nuts. Never thought about using 6-32 hardware. I'll have to give that a try. Thanks for the tip.

I do like getting a good fillet of glue around both sides of the centering rings; all of them. The method I use allows that. It does take a little more time but not much.

In post number two I mentioned that I had cut out the fins. The are actually pretty long once the three parts are assembled. Right at 27 inches. In post three I showed the body tube getting assembled. This is the post where the fins meet the body tube. For me this is when it starts to take shape.

I have assembled two of the fins and installed them on the body tube. They are drying and I think I'll leave them alone overnight. Maybe tomorrow I'll work on the other two. I did sand the leading edge to a slight taper and that took a little while even though I started with the lite ply fins. I think the part of sanding I don't like most is the mess. Other than that I find it pretty satisfying. One fin had a slight warp so I used some knife blades stuck in the body tube to keep the fin straight while the glue dries. The fin guide was generated on payloadbay.com, printed and sprayed glued (#m77) to a piece of cardboard which I then cut out with a single edge razor blade courtesy of Harbor Freight.


Bob

 

[burkefj]

This is great, I love falcons, I have only done one, a full scale D model, flew great....

 

[Bruiser]

I thought I remembered that you have a Falcon. I mentioned that I have designed several. I have my GAR 1 build going on over in "Low Power" and this build going on here. I did design another, the middle child



Not sure if it will be next but it'll be a nice way to complete the series of Falcons.

-Bob

 

[Bruiser]

I had what I feel was a really productive day. I prepped the last two fins and I've got to tell ya... Either that ply was a lot harder than the first two fins or I need some new sandpaper.

The four fins are on. I made the fin hinges and glued them on. It was looking so much like a Falcon to me that I had to slip the nose cone on. Of course it didn't happen if there's no picture...


Next step I think are the fin flanges.

Cheers,
-Bob

 

[Hobie1dog]

 

[Bruiser]

Today I worked on the fin flanges. I had to reference off photos mainly because they are much different than the flanges on the AIM-4D. I think I managed to catch the essence of them. It took much longer than I expected it too. They are tacked in place with CA followed by a bead of Elmer's. They still need some sort of fillet, especially on the fin side for scale appearance if nothing else. Not quite sure what I will make the fillet with but I have the weekend to ponder it.




-Bob

 

[Daddyisabar]

The fillet is easily made with bondo, green or white putty (same thing) high density spackle, CWF, etc. But over many flights you will probably experience some cracking that can easily be repaired. I launch on the high, hard Prairie and don't always use the biggest chutes, so results may very on the soft, green green grass of home.

The best and bullet proof is epoxy with microballons. That takes a little more work but the bragging rights with the High Power guys while waiting in line for the RSO table is well worth it!

 

[Bruiser]

I'm back for just a bit. I haven't been feeling too well and I am also working on taking apart a leaking 265 gallon aquarium so I can properly reseal it. I've been doing a lot of research on that.

I almost forgot that I needed to address the rear of the fin flanges. They have sort of a double taper to them that doesn't really show in the drawings well, or as it turns out, in photos of actual missiles. There's just not many pictures showing the rear of the AIM-4F or G model Falcons. I think I got them pretty close though and they certainly look the part


Next was to apply some fillets to the flange/fin joint. I decided to try Titebond Quick and Thick as I had it on hand and I use it on most of my fin fillets. This is the first time I've tried it where I wanted some pretty thick and wide fillets and it sorta let me down. There was a lot more shrinkage than I thought there would be. Of course I couldn't see how much it shrunk until I shot some primer on because the glue dries clear. There's not much of a fillet there and I am deciding if I can live with what I have or try again with another material.

But anyway, it has the first spray of primer on it now. Sanding off the fuzzies and what-not is next, followed by maybe making bigger fillets, then another coat of primer. Here's how it looks now. I am probably going to do something with the fillets as I can see the ridge from the tape and it should be a smooth transition. That bothers me more so than the size of the fillet.


That's it for now,
-Bob

 

[MarsLander]

Tape ridge angst is real...

 

[Bruiser]

I believe it

-Bob

 

[neil_w]

Dunno how I missed this thread but this a very nice build.

Next was to apply some fillets to the flange/fin joint. I decided to try Titebond Quick and Thick as I had it on hand and I use it on most of my fin fillets. This is the first time I've tried it where I wanted some pretty thick and wide fillets and it sorta let me down. There was a lot more shrinkage than I thought there would be. Of course I couldn't see how much it shrunk until I shot some primer on because the glue dries clear. There's not much of a fillet there and I am deciding if I can live with what I have or try again with another material.

In my experience, Q&T shrinks plenty. I haven't tried to measure whether it shrinks more or less than regular TBII. Maybe I'll try that when I'm bored.

Anyway: the thing about Q&T is not that it doesn't *shrink*, but that it doesn't *run*, and that's what makes it great for fillets. It also doesn't seem to form an airtight skin like TBII does, so thicker fillets will dry in less than 3 lifetimes. Bottom line, though, if you want large fillets with Q&T, you need to lay it on fairly heavy, and still build it up in multiple layers.

And yeah, it is *really* hard to see, dries completely clear.

 

[Bruiser]

Hey Neil, been watching your build. Hard part coming up over there. You know, paint and decals

Feeling inspired after an awful flight with the mini GAR-1 (AIM-4) I was inspired to work on this one a bit more today. I decided to make the fillets with CWF. I laid out some tape boundaries and smeared the CWF on. Next I smoothed it out with a wet finger. Then I immediately pulled the tape and smoothed it out again with a... wet finger. I tried a spoon but the CWF kept sticking to it.

The fillets came out pretty good and will need just a bit of minor sanding. They are not very thick. If I had to guess I would say not over 1/32nd of an inch. Now I am wondering if I should coat the CWF with something to seal and strengthen the CWF.

Any thoughts?

Pics to come tomorrow, after the sanding
-Bob

 

[Bruiser]

Here are the fillets after applying the CWF. It's the color changing CWF and they are still a little wet after smoothing them out with my wet finger


After some minor sanding I sprayed on a light coat of primer. Found a few small areas that needed a little more filler. After addressing them I sprayed some more primer and this is what I am looking at this morning



I need to start thinking about panel lines, decals and stickers now. Yes, stickers I think. Look at the markings n this photo. Don't they all look like stickers? Either that or they masked off an area, painted it a different white then did the stenciling. Seems to me that they wouldn't have gone thru all that when the stenciling could have just gone on the shade of white the missile is painted. Slapping stickers/labels of would have been much easier. What do you all think?


Thanks,
-Bob

 

[neil_w]

Those fillets came out good. I think CWF could be a good choice when the fillets are primarily cosmetic.

I agree about the "sticker" look... although white-backed decals will do the job as well.

 

[ljwilley]

Awesome build! Now you have to fly it!

 

[Bruiser]

Neil,

I have been thinking about getting some white decal paper for a laser printer. I've been using ink jet paper with my printer at home but don't really like the results with any of the settings I've tried. Have you experimented with the decal paper for a laser printer? Any suggestions?

Some of the labels will be going over red paint. Do you think the white decal paper will work there?


I'm trying to wrap my head around how to make the decals/labels. All I can think of is to to open Word, start typing the word/words and leave plenty of space around each word/s so that I can cut out each decal/label so that the white portion is the correct size with the word/s centered as needed. Might be a bit of a pita...

Levi,

It's got a a long way to go before time to fly it. It'll be lucky to be ready for our next launch day on April 20th. I might have to miss that one anyway due to prior commitments.

-Bob

 

[neil_w]

I have been thinking about getting some white decal paper for a laser printer. I've been using ink jet paper with my printer at home but don't really like the results with any of the settings I've tried. Have you experimented with the decal paper for a laser printer? Any suggestions?

I have had satisfactory results with the Sunnyscopa laser paper purchased on Amazon.

I have two issues with laser decals, neither of which should affect you here:
1) Color reproduction is not nearly as good as inkjet
2) Solid black areas are very matte, and are hard to get uniformly glossy with Future. However, clear-coating with spray works great.

I'm trying to wrap my head around how to make the decals/labels. All I can think of is to to open Word, start typing the word/words and leave plenty of space around each word/s so that I can cut out each decal/label so that the white portion is the correct size with the word/s centered as needed. Might be a bit of a pita..

Should be like any other decals. Lay out the text for each decal, and then draw an easy-to-see outline around it so you'll know exactly where to cut (i.e. just inside that line).

Actually that's probably backwards. You'll know the decal size in advance from looking at that picture. Draw the outline first, and then lay out the text inside the box.

 

[RocketTree]

Great idea to use white backed decal paper. When I built the AIM-4D, I painted all of the areas white where necessary and used clear inkjet decal paper. It was a lot of work. I might try white paper on the upcoming downscale and upscale versions where applicable. There will still be some decals that need to be made with clear paper.

 

[Bruiser]

That is a sharp AIM-4D. Did it start out as a Super Bertha kit?

-Bob

 

[Bruiser]

I've been getting little bits done here and there. I decided I wanted to do something to highlight the area where the facts of the fins meet. It shows like it's a panel line on the drawings but there actually are no panel on these fins. The fins seem to be a casting that are tapered to the front and to the rear of that line. I decided to make some sort of a "ridge" there to accent the area.

I used two pieces of masking tape spaced 1/8th inch apart and then smeared some CWF in the gap.


Once the CWF dried I sanded it down even with the masking tape


Then I removed the tape


Next I ran some thin CA over the the CWF to help protect it during the next steps. I sprayed multiple coatings of filler primer over the area, then wet sanded until I could see the CWF again so the CWF would appear more like a ridge than just a raised strip on the fin. Doesn't really show up much in the pic.


I also addressed the seam in the body tube be applying some thin tape to the seam location and then applying several coats of filler primer over the taped area. I wet sanded the area until the tape was fully exposed then I removed the tape to create a recessed area to simulate the seam


I've also bee working on the decals. I have them drawn up and scaled to what looks like the correct size. Now I just need to get access to a color laser printer to finish them up.

I think the next stop will be the paint shop. I'm not going to do rivets and screws on this one because there are no good photos that show them and they are not documented on the drawings. Now I am just waiting for a day when I feel good and the wind isn't too bad. The forecast is saying the winds should die down later this week.

I keep forgetting about the nose cone...

Cheers,
-Bob

 

[Bruiser]

The Super Falcon has visited the paint shop. White was the first to go on. I thought about painting the whole thing white. That would probably have made the red brighter but then I asked myself how would Hughes have done it? I decided since the missile separates at the same place the color changes they probably would not have painted the aft section white before painting it red so I did not either.


After allowing it to dry for a day I taped it off and took it back out and sprayed the red. During warm weather the conex that we use to store bad tires doubles as my paint booth. That's a broom stuck between some tires with the rocket slid over the handle


Here it is after just a little touch up at the paint seam


Now I just need to find someone that has a computer connected to the color laser printer to help me print out the decals. Oh, that and the nose cone

BTW, Tamiya tape and Krylon Acryli-Quick paint. Love that stuff

-Bob