A scratch build as yet un-named

Hi Folks,

It has been a while since I've posted a build, in part due to lower build frequency, and in part due to lack of time and energy to post builds. But with a few days off, and the responsibilities of the holiday largely behind, I've got just enough enthusiasm to show you what I'm working on.

A couple years ago I built something called Project Red Queen:

View attachment 143313



It flew great, but the recovery system I had using rear eject wasn't optimized and it crashed on first flight. I rebuilt it a bit, and had a better second flight, but then retired it from flight.

I've been meaning to make a zipperless version of it, and finally started a build of a BT-55 downscale, with some modifications. I might call this the Red Prince, or perhaps find a different name theme. Anyway, the build is essentially done, but I have to figure out a finishing scheme. Stand by for a catchup on the build... then some finishing decisions.

Looks great!

Being I'm a huge RE fan I love it. Great work.

How odd. My attachment picture isn't showing, in the original post... just a link to it...

Here is the downscale build as it stands:



I have not yet cut the strakes that will go on, and the side fin pod cones just arrived today from eRockets and are not yet glued in Otherwise it is build complete.

The original BT-60 version suffered from a few faults:

The tailcone ejected, pulling out the laundry... but it wasn't a great system. Zipperless would have been better.

Also, being a relatively heavy rocket, it put stress on the fins on landing. Ideally it should have been recovered under a large parachute but due to relatively small fields I fly on I used a smaller chute to avoid losing it to the winds. Really it should have been constructed with through the wall fins.

So, the downscale will be constructed with a zipperless recovery baffle system and through the wall fins.

I started with my Rocksim file for the Red Queen... I downscaled it to 81% (BT60 to BT55 conversion) and printed out fin patterns on cardstock. I then drew on some tabs a bit longer than needed.

Meanwhile, I printed out a base view to use in positioning the fins radially. I glued a used engine onto the base view. This will help when I mount the fins.

Marc_G said:

The original BT-60 version suffered from a few faults:

The tailcone ejected, pulling out the laundry... but it wasn't a great system. Zipperless would have been better.

Also, being a relatively heavy rocket, it put stress on the fins on landing. Ideally it should have been recovered under a large parachute but due to relatively small fields I fly on I used a smaller chute to avoid losing it to the winds. Really it should have been constructed with through the wall fins.

So, the downscale will be constructed with a zipperless recovery baffle system and through the wall fins.

I started with my Rocksim file for the Red Queen... I downscaled it to 81% (BT60 to BT55 conversion) and printed out fin patterns on cardstock. I then drew on some tabs a bit longer than needed.

Meanwhile, I printed out a base view to use in positioning the fins radially. I glued a used engine onto the base view. This will help when I mount the fins.

View attachment 278543

Click to expand...

Looks like you've already built another great looking rocket! Looking forward to a detailed description on your building and painting processes.

(Your photography is starting to look like mine Marc!)

Any new people may enjoy reading Marc's Red Queen build tread and want to get a feel for Marc's building style and build thread commentary. Lot's a good stuff!

Go to: www.rocketryforum.com/showthread.php?55678-Project-Red-Queen-it-has-begun!

Thanks Bradycros! My photography skills aren't quiet there yet... and the camera I use to document builds is starting to go on the blink. But, I'll do my best.

Any substantial build starts with a plan, and one seminal component. For me, the component was a tailcone I got during SEMROC's going out of business sale a while back, before it was bought by Randy from eRockets (RIP Carl M!).

Anyway, the tailcone was for BT-55 tubing and contains a hole bored for BT-20 engine mount tubes. So, I obligingly put a BT-20 through it, epoxied it in, and gave the tube a centering ring. I had measured all this before hand to come out right.



I made sure the motor mount tube stuck out a bit below the tailcone so I would have a good surface to tape to, to affix an engine for flight (to prevent the engine from ejecting). the centering ring is suitably far forward to give me plenty of unencumbered room for through-the-wall fins.

Since my fin arrangement isn't just a simple 3 or 4 fin, 120 / 90 degree type arrangement, I needed a way to properly mark the tube, since none of the standard marking jigs would work for my custom angles.

Never fear, this is the beauty of printing out a base view.



OK, there's a lot in this picture. I started with a section of body tube. The one shown here, before I cut the slots. :grin:

In the background you will see some scrap BT-20 with centering rings for BT-55. I inserted this into my virgin body tube, and lowered it onto the spent engine glued to the base view. I took it all the way down (Sorry, no picture) so that the body tube was in contact with the cardstock printout. With that in place, I carefully marked the tube in the locations (angles) where the fins would eventually go.

From those tickmarks around the bottom of the tube, I extended lines forward using the bit of angle-aluminum on the right of the picture.

I made sure my lines accounted for the thickness of the fins I would be mounting. I measured the shoulder height of the tailcone, and transferred that measurement to a line around the body tube. That marks the bottom edge of any fin tab I would be passing through the tube. A similar line marks the aft edge of the centering ring on the motor mount tube. No tab material north of this.

I carefully cut the length of the body tube down so it was just a few inches longer than the fin mounting surface. This will prepare it to be the right length for my zipperless recovery coupler with internal baffle.

The fins are traditional, my own designed shape, nothing special. Made out of basswood with tabs, with bevels front and rear. The larger ones (wings) are made out of 1/16" basswood, the smaller ones (to which pods will be mounted) are a bit more sturdy at 3/32".



I don't have a fancy way to make the tabs... I get it approximately right in the computer, print a template, then trim away on a cardstock blank until I've got it right. I always leave a bit excess wood on, sanding each fin's tab so it makes proper contact with the motor mount tube.

Here's the test-fit of one of the fins (numbered!) before I sanded a bit of the tab off to make perfect contact.



Recognizing that this model will probably have some hard landings, I wanted to reinforce the attachment of the fins to the motor mount tube. Normally, I would use some heavy-walled tubing as the motor mount for extra strength, but I didn't have any on hand. So, I took a piece of regular computer printer paper, and put a thin layer of wood glue on it. One complete wrap around the motor mount, extending from the shoulder of the tailcone, to the forward centering ring. Once dry, I put a thin layer of wood glue on the outside of the paper. This will serve as the initial layer of glue for a double-glue joint when I attach the fins.

That dry, I used some epoxy and attached the body tube to the tailcone/motor mount/centering ring assembly. I chose epoxy because I wanted plenty of working time without things seizing up. The body tubes I'm working with are very tight, compared to the tail cone and coupler stock I have on hand.

While the epoxy was setting up, I put wood glue onto the attachment points of the fins (tabs and the parts of the fins that will butt up against the body tube). This is the first layer of glue in a double glue joint, on the fin side. I also put a thin layer of wood glue on the part of the body tube that will be mating to the fins.

That done, and all epoxy and first-layer-of-double-glue-joints set, I then prepared to mount the fins one by one. I put the tailcone/body tube assembly onto the spent engine, and aligned the holes cut earlier with the lines on the base view.

(retrospective: I seem to have been derelict in describing the cutting of the slots... I used a hobby knife and that angle-aluminum piece seen earlier, following my markings based on the tab locations. The only trick to it was I put a coupler into the tube to support it, before cutting, to prevent accidental squishage of the tube)

OK, back to mounting the fins. Each fin got a thickish dollop of Titebond No Run No Drip (Molding and Trim Wood Glue) on the tabs that will contact the motor mount, and regular Elmer's Carpenter's wood glue on the root edges that will mate with the body tube. Each fin so treated was carefully maneuvered into place, and held there for a minute or so, sighting down the fin to make sure it lines up with the markings on the base view. After a minute the fin is pretty much fixed in place as the glue grabs. I let each fin sit for 15 minutes before moving onto the next, just in case.





Since some of my fins sweep forward and others sweep back, and each fin has a specific location on the tube, I was super careful to attach the right fin to the right location.

Meanwhile, can someone PLEASE tell me why sometimes my pictures show as pictures, and sometimes they show up as attachment listings? This seems to be fairly random, and sometimes seems to change each time I refresh the page... here's what I'm seeing:



Oddly, if I see those attachment tag indicators rather than the picture, then go in and edit the post (don't have to change it, just go into the edit screen), then save the "edited" post, the pictures show for me. How strange.

Edit... I eventually replaced the pictures with re-uploads to see if that fixes it.

The zipperless coupler baffle will simply be a 2" piece of BT-55c coupler, into which three "half moon" (actually 60% moon) baffles made out of 1/32" plywood are inserted. The top-most baffle is doubled out of two pieces of the plywood, laminated together with wood glue. That top-most one is drilled and a screw-eye put in.

The baffles are held in with trim and molding glue, and each baffle surface is also coated with a thin layer of that glue, as a heat-protector. I've found it works well.

The real story is how to make the baffles.

Step 1. Take your piece of coupler, and using a pencil, mark the inner radius of the coupler four times on some 1/32" plywood stock from Micheal's / Hobby Lobby / etc.

Step 2. Cut out those roughly using sturdy shears, making sure to leave excess material outside the lines.

Step 3. Line up the cut-outs and put a brad through their center, into a piece of scrap wood, such that some of the cut-out is hanging over the edge.

Step 4. Buzz-sand them against a disc or belt sander, turning the cut-outs around the brad, until they are perfectly circular, stopping at the line marking the circle.



Step 5. Cut them down to 60% size



Step 6. Glue them in, starting with the aft one. Make sure the joints are well reinforced. Attach a screw eye to the top one before gluing it in. You'll se a picture of the completed coupler later... sorry I don't have a picture of it stand-alone, but you'll see what it looks like when the assembly gets glued into the body tube.

While working on the coupler, I gave the fin can one thin fillet with Carpenter's Wood Glue, then when that was dry, a heavier fillet with the Molding and Trim glue.



I then used carpenter's glue for double-glue joints to put on the side-pod tubes.



When those were dried I filleted them with the molding and trim glue.

This rocket is constructed from two 18" BT-55, each of which has been cut down by a few inches to remove some bent / oval-squished areas. The total tube length, not counting tailcone or nose cone, is about 30".

As you've seen, the rear of these two 15" tubes has been cut to make the fin can plus a forward section. The zipperless baffle coupler will hold the fincan and the forward section together. But, I need one more coupler, to join the forward section of the rear tube to the other tube up front.

This second coupler will also serve to anchor the forward attachment bulkhead point for the shock cord, which will be Kevlar.

I took a 2" piece of coupler, and made a 1/32" plywood circle matching the outside diameter of the coupler. Then, I used some stiff balsa (really dense stuff) and made a 3/32" circle of that. I laminated the two together and glued it to the forward end of this coupler.

Here it is, holding up the fincan into which the zipperless baffle coupler has been epoxied:



You can see the screw eye I mentioned earlier, attached securely to the topmost baffle plate. The coupler was saturated in thin CA, which will then be polished to make the coupler super smooth for good deployment at ejection. Not shown, the inside of the BT-55 tube that will mate here was also treated with CA. It will be smoothed to match well with the zipperless baffle coupler.



As to the forward coupler/bulkhead I passed my Kevlar through a hole in the center, and used a strip of basswood to hold it up. I made two loops of 100# test Kevlar, wrapped in doubled parallel braids around the basswood, then glued the edges of the basswood in place (avoiding getting glue on the Kevlar, as that would weaken it).

Right. Putting all these bits together gives us what I showed up top:



Close, but not quite a complete vision. There's lots to do yet.

Specifically, strake fins and a launch lug. And Let's not forget the antiproton emitters.

For the strakes, I just cut out some narrow, long fins that matched the vision in my head. There was no scientific basis for the length; I haven't run a rocksim on this thing... I know from my prior version that the design is overall stable, and I'm not worrying about the details. I'm just going from intuition. So some 1/16" basswood strakes got cut, and a strip of that basswood for anchoring the launch lug. I prefer to put launch lugs at least 1/16" away from the body tube, to reduce rod-rash.



Eventually I cut a 3/16" launch lug to size with tapered front and back angles, and glued it on:

The antiproton emitters are made out of bamboo kitchen skewers.

So, they are round in cross section. The surface to which they will mate (the tip edge of the fin) is flat. What's a good way to do that? One way is to sand the skewers to create a flat surface. But I have found this reduces the strength of the part, so instead, I used glue. I slathered glue around the mating area of the skewers, and set them on plastic to dry. The pooled glue against the plastic dries flat, a perfect mating surface to go against the fin. Double glue joints finish the job.



I also decided I didn't like the look of the launch lug, so I made a cowling or fairing for it. I cut a piece of extra BT-55 down, a bit longer than the lug, and used a circle-cut-out to mark a circular line inside the BT-55 scrap. With an Xacto knife I cut out slivers of the fairing.



I then penetrated the cardboard with CA, let it dry, and polished it smooth.



At this point I'm caught up with actual progress. I've put a bit of glue on the edges of the fairing, as the first layer in a double glue joint, mating to the insides of some of the strake fins. Stand by, there's more to come...

The cowling/fairing has been installed using Carpenter's wood glue.



The build is now complete. Finishing starts tomorrow!

Looking really good Marc_G. I don't post very much but I do like to keep up with what our friends are working on.

Thanks Sheryl! My thoughts are with you. Thanks so much for taking the time to compliment my build.

All the best,

Marc

The fillet of wood glue used on the fairing dried with lots of pinholes and shrink zones. This is not unusual... Elmer's Carpenters' Wood Glue shrinks a lot when it dries, and it has surface tension effects that cause this kind of void creation.



So, it's not a good filleting glue. But it's great for holding things together. I gave a second fillet using Molding and Trim Glue. Much better. It shrinks relatively little and has surface tension characteristics that reduce the pulling-away that can cause voids.



I also polished the zipperless baffle coupler with a 320 grit sanding sponge. followed by some 400 grit paper. Also the inside of the tube where this will mate. Made a nice smooth joint that shouldn't have separation problems.



Here are some pictures before spraying gray primer.



I warmed the Rustoleum Auto Filler Primer in some hot water, shook thoroughly, and gave the rocket a complete coat. Not too much on the nose cone which has lots of relief detail, but an extra heavy (but not enough to cause runs) spray on the fins. After it had dried an hour in the garage (with the garage door open), I sprayed another coat on the fins, wood cones, and around the body tube spiral.

I should note that I forgot to document the hardening of the balsa tail cone and pod cones with thin CA. I apply with a saturated Q tip (replacing the Q tip if it starts to harden). I apply as much as the wood will drink in, then just a bit more. With proper ventilation of course. Then, when it is fully cured, sand with 220 grit then 320 grit. The hardened balsa is easier to fill and sand without sanding flat spots into the cones.

Tomorrow I will take a picture of the gray rocket.

I REALLY need to finalize the name and paint scheme for this bird!

The first coat of gray primer is always revealing. It shows every little imperfection, pinhole, spiral groove, and other defect imaginable, and several that aren't imaginable until you see them.

However, this time, the primer gods were kind, and my "Red Prince" actually looks pretty good in primer.





There are some slight spirals visible (mostly will go away with sanding), and some definite grain on the tail cone, and some join lines at the body tubes, but pretty much just the expected stuff.

Today I used some white Tamiya putty to cover the worst of the problems, and next time I get a chance I will sand things down and see where we are. This build will progress slowly due to work commitments this month, but I'll post whenever I can make some progress.

"Red Prince" looking really good, Marc_G.

very nice lines and design. I really like the innovative air scoop launch lug fairing, I am going to incorporate that into my next build. Great idea.

Last weekend I sanded down the primer, and used some Tamiya putty in areas where there were balsa voids, tube joins, etc.



On sanding that stuff down, most areas were nice and smooth but one area had odd depressions. Either corners from a sanding block or my own fingernails depressed the balsa of the cone (which has a shell of CA, but is still relatively compressible).



I covered the area with some drywall spackle. This is the material that sands the easiest, and it works as a decent filler.



I used the same technique where the nose cone joined the body tube (Remember, this nose cone is glued on, since the separation point is at a coupler further aft). I didn't want to sand aggressively near the plastic nose cone which has lots of details on it.





Meanwhile things have progressed on the lower part of the rocket.



The areas with spackle fill were rubbed with a Q-tip soaked with CA, and the CA flows into the dried spackle and makes it super hard, but still polishable with 400 grit paper. Nice and smooth, and a very good surface to paint.

Red Prince is ready for acrylic undercoat.



I will be using Auto Air Sealer Dark and Sealer White.

Yesterday, I took to the Red Prince with some Auto Air Sealer White and Sealer Dark. To be fair, going over the existing primer with an additional sealer is wholly optional. But I usually do it when using acrylics, so that the topcoats have a uniform base to bite into, and to make sure there's a consistent color under them.

Since I'm going for an organic-looking finish, I don't need, or want, the final primer coat to be uniform. So, starting with my somewhat sketchy primed/sanded/puttied Red Prince, I first applied some white sealer.



Then some dark:



You get the picture. Note that when I switched to Dark, I didn't bother cleaning out the airbursh cup. I just went straight to the new paint, so part of the primer is grayish. Cool.

Next up was an assortment of red paints. Semi-opaque flame red, Wicked crimson, Detail Scarlet... even some Rock Star Sparklescent Red. Mostly I did red over the lighter-primed areas, but over some of the black too... Just dump the new paint into the cup and move on. When I had enough red on I put black paint in, and went at it, covering the dark-sealed areas as well as going over parts of the red, with different thicknesses of spray, different flow rates. Eventually:




It's not done... I still have to look into what decals I've got, and I have a few other tricks up my sleeve. But that will have to wait until after a work trip. I'm busy this week, then leave next Sunday, so it may be a couple weeks before I make further progress.

Can't wait to see this thing in the air!

Marc

I've been busy with work and family stuff the last few weeks, so this build has just sat around since then.

I looked for the leftover decals from when I built Project Red Queen, and found a sheet with some leftover red queen name decals (not useful) and a few various sized Umbrella Corporation logos. Those I can use on this. I found a lot of extra decals for old projects I planned but never did... different scales I never actually built. I'm bummed that Excelsior has had so many problems with the printers... I really would need white decals for a name decal.

Instead I'll go without any name decal and just use the Umbrella Corporation logos. I may use my paint pens to emphasize some of the feature lines on the nose cone.

The prince is mostly done.

I decided there was no need for any more detail on the paint job:



Here is a closeup of the nose:



I used some cockpit window decals I got from Gordy a while back:



Added a few Umbrella Corporation logos...



(note biohazard symbols on the pods... maybe those aren't just engines, but tanks of some agent...)



(there are a few more small ones on the wings, not shown)

Black extra fine paint pen to sketch around the cockpit hatch.



She's looking feisty enough. Now to consider what sort of coating. I don't think glossy is what I'm going for.

Suggestions on a good satin / matte overcoat? I almost always go for gloss, so I'm in uncharted-by-me waters here.

Wow, very nice work!

Can't wait to see some launch pics!

Thanks. I'm itching to get it in the air too!

That's looks AWESOME!:clap::clap:

Nice builds!

A very good looking build Marc! Thanks for the build thread and photos.