Lockheed Defender Build

Your mileage may vary? That's what google told me when I asked...

Yes, about half of it was covered. How do you know when to stop sanding if you coat the whole thing? I tell when it's time by the appearance. When the cwf is just "spotty" I stop. I figure the little depressions I didn't get with the cwf the primer filler will take care of

I like the brown Estes' body tubes. They seem to take sanding well. I bought some Semroc tubes and they don't seem to have the coating the Estes tubes do and they don't sand well. Very easy to get fuzzies on them. Guess there's always primer/filler to take care of that. I think I will try your idea on the next build that uses Semroc tubes.

-Bob

Ya, the brown tubes are better for sure. I think the shinny covering is called glassin (?) IDK. YRMV= Your Results May Vary. As far when to stop, that's just comes with experience I guess. Some people don't get that picky. I just do it that way cuz I figure I have most of the tube covered anywhoo.
I go a lot by the feel. I found that going by site doesn't always work in my case. You have to take all the info that people give you and sort out what works for you. I do things that others wouldn't do and versa visa. LOL/ Just have fun. And if your happy with the way your birds come out..thats what really matters most.
I me-self hate decals. I suck at putting them on, so I don't finish my scratchers with a lot of little details/decals.
I also get more of a thrill out of the design stage, the built and then see them fly without a cato/crash. I have a few scratchers that made it to the primer stage, they flew and that was it. Move on to the next design. Again, that's me. Do your own thing.

Scotty Dog said:

Very nice job on cutting the pieces parts. I like to put filler on the whole BT. Then sand it down.

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I tried this yesterday on a 6" piece of BT55... worked pretty well. I used a very thin mixture of CWF, slopped it on the tube and spread it thin with my finger. Knocked off most of the bulk with 400 grit, then finished with 800 and 1500 to avoid scuffing the glassine.

Pretty quick and easy I must say. In addition to being easier to apply it all at once (rather than following those damned grooves), it's also easier to sand the whole tube at once. I'm not 100% sold yet, but I'm going to cautiously keep doing it this way until I run into a problem.

Thanks for the tip!

I am going to have to give applying cwf to the whole tube a try. Reading that you found it easier to sand is the extra encouragement to try it out

Been working on the ram jet intakes for the Defender. My order came in from eRockets but I did run into a little snag. I ordered some Estes BT20 nose cones but what came wasn't what was pictured. Apparently Estes changed the packaging. I was expecting two pairs of nose cones but I got four of varying shapes and sizes. Luckily I had one nose cone that matched up with one of the new ones so I was able to build the front of the ram-jets.

First step was to cut up the nose cone. I took a section out from the middle and I cut down the shoulder to help lose some weight. It just needs enough for the glue to hold it in place.



Next I cut a disk out of 1/8" balsa and epoxied it inside the cone. Then my handy Dremel tool made a hole in the center of the disk.



last step was to epoxy the tip of the nose cone to the inside of the balsa disk



Now I have the front of my engine pods ready. Since the remaining three Estes nose cones are all different I think I will make some transitions for the tail cone part of the engine pods.

-Bob

These might work:
https://www.erockets.biz/semroc-balsa-nose-cone-7-1-7-cone-nozzle-set-sem-bc-715cn/
https://www.erockets.biz/semroc-balsa-nose-cone-7-2-1-cone-nozzle-set/
Both fit an ST-7 tube, which has the same ID as a BT-20 (but slightly thicker).
Kinda pricey if you just need the tail cone, but good to keep in mind for future builds.
I like the craftsmanship of your nozzles.
But my motto is "always take the easy way out".

Kuririn,

Those are pretty much what I had in mind. Never thought of looking for them already done. I just figured I'd have to modify or scratch something out

There's something to be said for taking the easy way out but I do like to build and saving a little bit at the same time is the icing

-Bob

I have attached the engine pods to the wings. I slotted the BT20 tubes, slide them on the wing and glued them in place. Then I slotted one tube for the rudders when I thought I should cwf the tube before I glue in the rudder so I thinned some out and brushed it on. I had not slotted the other tube for the rudder yet but I brushed the thinned cwf on it as well. THat actually worked out better when I sanded the cwf because the tube without the slots was more ridged. I have both pods sanded now.

I also papered the rudders and sealed three edges with ca. The other edge will be slid into the engine pods so it didn't get the ca as it will be getting Elmer's.



-Bob

Looking good!

So I've been doing a little of this and a little of that today.

I started working on the engine tail cones. I haven't heard anything back from Estes so I'll build my own. I started with a bulkhead of 1/8" balsa to have something to glue to. I inset the balsa halfway into the bt20 tube and then glues on the transition. I used a paper plate for the cardboard and added a wrap of printer paper. I am going to wait to glue them on to the engine pods until later because they are fragile. I need to cwf them too but that'll wait until they are glued on.



I also glued in the motor mount. The top ring gave me quite a hard time. I had applied some epoxy in the tube then I pushed the top centering ring in to the right depth. When I checked on it a short time later it had twisted. Luckily I was able to pull it out and get it back in before the epoxy had set up.



I also built up the wings, strake and canard assemblies. I glued them on to the body tube but I ran into a problem too. I made a small section of the wings ttw but apparently the material did not reach to the motor tube because I have some flex. I am debating about cutting the rear centering ring out so I can see what is going on there. Lesson learned here is to hold off on that final ring until the fins are in whenever possible..


-Bob

Nice! I like the look of the cutouts in the strakes, aerodynamically nonsensical though they be. (that is not a criticism, my designs are all ridiculously draggy)

Bruiser said:

I also built up the wings, strake and canard assemblies. I glued them on to the body tube but I ran into a problem too. I made a small section of the wings ttw but apparently the material did not reach to the motor tube because I have some flex. I am debating about cutting the rear centering ring out so I can see what is going on there. Lesson learned here is to hold off on that final ring until the fins are in whenever possible..

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That's not easy in LPR rockets. Let me suggest a different lesson: always cut TTW tabs a bit too tall, and then sand them down to fit. It's hard to go in the other direction.

Don't get too attached to those cutouts. They are for lightening and are going to be covered up

I got the aft centering ring out. The tabs on the wings were in full contact with the motor mount tube. The glue was still rubbery after 4 hours. I don't know if Elmers glue can go back but I am going to buy a new bottle.

That is sage advice. I have had to add on to tabs before when I approximated. This time I took exacting measurements off the parts I was using to prevent that

-Bob

Bruiser said:

Don't get too attached to those cutouts. They are for lightening and are going to be covered up

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Ah, wasn't sure if you were still planning to skin the chines (that phrase has a nice arcane ring to it, doesn't it?)

I got the aft centering ring out. The tabs on the wings were in full contact with the motor mount tube. The glue was still rubbery after 4 hours. I don't know if Elmers glue can go back but I am going to buy a new bottle.

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TB2 for that stuff, man. White glue for some specific situations, but otherwise TB2. Your mileage may vary.

New question: it looks like the top slots for the winglets are centered in the pods. Do you still plan to tilt the winglets inwards? If so, I guess you'll just let the winglets sit non-perpendicularly to the pods?

If I may suggest, after your paper tail cones are assembled in place and the glue is dry, use a Q tip and paint them with thin CA. Stiffens the fibers to about the consistency of vacu formed styrene. You can then sand them smooth.
White glue has the same bond strength as wood (yellow) glue, but takes longer to dry.
So if you want quick grab and quick drying, use yellow glue.
If you don't want the quick grab, then use white glue.
It's a good idea to dry fit everything before applying glue. Lesson learned the hard way (many times).

Heres a little something. Coffee creamer cups make great tail cones. Or nozzles, ect. They come in different sizes too. Not sure about what glue sticks to them. I haven't used them in awhile. The bird in pictures has not been built. Mostly a mock up kinda sorta. I have all the pieces parts to build it tho. Anywhoo-- more food for thought. Is your brain hurting yet ? lol..

Scotty Dog said:

Heres a little something. Coffee creamer cups make great tail cones. Or nozzles, ect. They come in different sizes too. Not sure about what glue sticks to them. I haven't used them in awhile. The bird in pictures has not been built. Mostly a mock up kinda sorta. I have all the pieces parts to build it tho. Anywhoo-- more food for thought. Is your brain hurting yet ? lol..

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Yeah, ToneDeafjunior had a build using ketchup cups for nozzles. I think it was a Proton rocket.

Here I thought the general rule of thumb was white glue when paper is involved

Wood glue for wood

Epoxy only when you can't use something else like plastics and composites

Then there's super glue (c/a) which I will be using to strengthen the tail cones. After they are glued on, I'll use the cwf to make them nice and smooth. If Estes come thru in the meanwhile then I will probably go a different direction It's only been a day so there's still hope the will at least reply to my email.

Neil, I am not sure what you mean by perpendicular. The slots are cut right on the centerline. The rudders are going to lean in. if you were to look at the front view the rudder would not be in line with the center of the engine if that's what you mean.

Bob

I've been doing some glueing this morning. I am on my third fin and will get the fourth one on in just a bit. Decided to make a post here in the meanwhile so I don't rush it.

I've been struggling the last few day to extrapolate the angle of the fins/rudders. Neil had suggested 20 degrees and but looked a little more than in the picture. Finally last night, just before falling to sleep and after much research it came to me that the angle is supposed to be the same angle as the sweep of the trailing edge of the fin/rudders.

This morning I started with manufacturing a custom angle template and here you see it at work


So Neil, is the alignment of the fins relative to the center of the tube what you were asking about? They are off center to the inside of the tube but on center to the outside of the tube.

-Bob

It was not only the rudders that saw glue today. I also glued on the strakes and I very happy with the way this is "fleshing-out".




I've got a lot of fillets to do but in the meantime I still need to figure out the cannon pods and the canopy. I'll have to do some research tonight

-Bob

Looks great, you are moving ahead quickly.

Never mind the thing I was asking about, it's minor and no longer relevant.

That looks so cool.

So last night I was reviewing all the data in my head trying to sort out the canopy profile and how to model it but I kept running into mental road blocks. I kept think about the nozzles. I really wanted to use a cut odd nose cone but my plan failed due to a wrong picture on both the site I ordered my nose cones from and on the Estes site. I've been a little miffed about that since and Estes never answered my email about it. But I digress...

It came to me that Scotty Dog actually provided the answer. I had dismissed his post about creamer containers for this model because they were too large. Well last night it dawned on me that I have scissors... Why not cut the creamer container down and glue it to a cardboard nozzle? So that is exactly what I did. It took some playing around with the transition tool to match the taper of the creamer container but after four attempts I got it. I made the transition out of a paper plate and I glued the "creamer skin" to the transition with epoxy. CA glue didn't seem to work.




I just realized that it may not "take" paint. I use Rustoleum 2X which is supposed to stick to plastic. I'll have to do a sample spray out.

-Bob

Looks great. I think if you prime you’ll be ok, but testing is always a good idea. In case of problems there’s always plastic-specific primers.

Not only did I get the nozzles worked out, I also figured out the canopy today. I started off with five drawings based off the drawing and with Neil's help we narrowed it down to the best choice. Then I built a poster board mock up and decided a few minor changes were needed that I incorporated into the final design.

It is built around two basswood formers that were exactly the same. One was glued to the body tube and the other to the nose cone. One former then got a locating pin glued into it. Then I added a balsa spine down the centerline. Next I added the top pieces, the front panel, then the sides went on piece by piece. All balsa to balsa joints were CA glue, balsa to cardboard was Elmer's and balsa to plastic was epoxy.

So here is the side view



Here it is with the nose cone slid forward



Final shot is the mating surfaces.



Everything is still in the rough. I still need to sand and decide if I am going to paper them or cwf and follow with paint.


Last big hurdle is I still need to figure out the paint scheme

-Bob

Nicely done! CWF would be the easiest way to handle that IMHO. The whole thing will take you 5 minutes.

Looking great. What ya doing for launch lugs , recovery system and pigment colors ? I didn't see where you attached any Kevlar and or cord to MMT. OK, I went back thru and see your baffle in the very beginning of thread. I'll assume your sliding the baffle in from top side with cord attached to that . Cool.

That looks great. The peg fitting on the nose cone canopy is a nice touch!

Thank you all.

The baffle has a screw eye in it that I will attach a loop of Kevlar string to. The baffle is glued in so there is a 6" recovery bay. Then there will be a split ring that attaches the Kevlar to 1/4" braided elastic that is perhaps three to feet long. The other end of the elastic will connect to the nose cone. there will be a loop sewn into the elastic about one foot from the nose cone. A swivel will go threw that loop to attach the parachute.

I'll be epoxying on 1/4" launch lugs to the "bottom" of the Defender.

Been thinking about the paint scheme. Thought about a "splinter camo" scheme but I don't think I like it.



I am now thinking of something just a little different. I still need to draw it up.

I put the peg in just to keep it in alignment. I think it'll be a big help with the painting too.

-Bob

Maybe something more like this

-Bob

Both pigment schemes look great. Me-self, I like the black . One thing I really like about this bird is that it looks FAST just sitting there. Like I said, "Im a HUGE fan of rocket/planes." Very nice !

I am trying to make up my mind about going with decals or paint masks from a cricut. I've never made either. Last time I used decals was over 40 years ago and I've never used a cricut machine. All the lettering on the top side will be a light gray with dark grey on the bottom. I want some red outlined "no-step" areas on the back of the wing, upper side.

-Bob