Brief:
This is the Estes BT-80 sized V2 that was recently re-issued. It is a 1/25 scale model of a production V2. It has significantly over-sized fins for stability purposes, and a minimal amount of scale detail. It flies on a 24mm motor, recommended to be a D12-5, although most will look for more power.

Construction:
The components are typical Estes, which is largely pretty good. The body tube is a standard BT-80. The nose and tail cones are rotational molded plastic. This is done reasonably well with visible, but acceptable, mold lines. The tail cone has a significant discontinuity ridge near the tenon and also is not entirely fair, showing a significant concavity right near the fin leading edge. The nose cone is not really very accurate, being a bit too short and has a rounded tip. The round I chose to model was White Sands round #56 which had a pointy nose, as do most.

The shock cord attachment is a molded plastic loop, which as you will see later, was not the brightest thing in the world. The recovery system is also typical Estes, with a plastic parachute. The shock cord is the usual absurd 1/8" short elastic cord, which lasted about 2 seconds after I opened the package. I replaced this with 3/8" sewing elastic, 3 feet long.

The fins are die-cut balsa. The wood in my kit was typical "rocket wood"- about 15 lb/cu ft c-grain. This was satisfactory and I used it, but the model could be lightened significantly with lighter wood. The centering rings and motor mount are also the usual Estes components, with fiber centering rings and a BT-50 motor mount. These might seem a little minimal for something that's likely to get E's and low F's, but the fins go through he tail cone all the way to the motor mount tube, and the whole assembly is very well braced even stock.

The decals are typical water transfer types (in mine, at least). They are minimal but appropriate for a production model.

The kit is fairly easy to build. It's pretty standard except for the tail cone/fin/motor mount assembly. The slots for the fins are molded into the tail cone but not cut through. Cutting through this is a tricky operation. If you just cut it off flush the slot would be far too wide. This is a problem if you do not plan to add large fillets. I started out cutting the top of the molded fin slots just far enough down to get through, and then spent about 2 hours with a file widening them to just 1/8" for the fin. You have to very careful doing this to avoid getting the fins on crooked later. In retrospect, I would probably make a jig for this operation. Once this tricky operation is done, then the TTW tabs on the fin have to be very carefully fitted to just touch the motor mount tube. They are all longer than necessary, and they need to be sanded very carefully down to get the root edge that bears on the tail cone just touching. It's not too hard to do, but it's a little fussy. Don't take off too much! Both of these operations are critical to get a good fin/tail cone fit. The good news is that once it all fits together, its pretty darn sturdy, even without fillets.

The rest of the construction is pretty straight-forward. I did a little extra detailing of the fins and engine area on my model. I looked at a bunch of pictures from Rockets of the World and other sources to get a good visualization of the fin shape, and sanded this in. The fins are pointed on all edges, and expand to full width in about 1/4" on this sized model. I also added 1/64 ply shrouds at the base of each fin to support the end of the fillets. This is the area where the jet vanes go into the base of the fins. I suggest studying the pictures very carefully in this area to get an idea how this looks.

Another thing I did was to cut the aerodynamic surfaces loose from the fins, finished these separately, then glued them back on. This gives a good representation of their function. I also added the control push-rod fairings. I made these out of 3/32 basswood.

An additional modification I made was to make a conical nose tip from .010 styrene sheet, and glued it to the tip of the nose. This gives it the desired point, but is weak enough to deform if it hits someone. Also on the nose, I scribed the hatch outlines into the plastic with a bare metal foil scribe. This was specific to my particular round.

Finishing:
Finishing was pretty simple. I used Squadron White putty to finish getting rid of the mold lines and the tail cone joint. One thing pretty lacking on the kit is the prominent fillets at the fin/body joint. Leaving this off would make it very "model-like". Examination of the photos indicates that this fillet is sort of conical, which a very tight radius at the LE and pretty wide at the TE. This precludes using a tool to make it. I used AeroPoxy Light filleting epoxy to make the fillets. I put down the blocking tape in a rough triangular footprint to try to get the conical look. Then I applied the material, and just eye-balled the cross section while shaping with my finger and a bunch of water. It's sort of like clay sculpturing. The fillet ends at the tail on the 1/64 ply inserts I added. Do them one at a time and it can be done. A little sanding when hard to fair them in to the fins/tail cone and it comes out pretty good.

I used K&B UltraPoxy primer over the whole model, which sealed everything up well, and filled the last of the little pits left here and there. The round I was modeling was mostly white with a black roll pattern, and some bare metal details. I painted the whole model white with K&B SuperPoxy. I then masked off for the fins and shot them with SuperPoxy black. I did the roll pattern in 3 separate maskings - top and bottom rings first, then the diagonal lines tilted to the left second, and the diagonal lines tilts to the right third. You could do it all at once, but then the tape overlaps might be a problem. I used 3M fine line green tape for all masking.

For the bare metal nose, I sprayed SNJ Spray metal with my airbrush. This works great and is pretty durable compared to some of the other metal paint. For the bare metal around the hatch, I used Testors aluminum paint in a #1 Rapidograph pen. Not surprisingly, this got clogged up a bunch of times, and was a real pain. But I can't think of a lot of better ways to get such a fine line. Panel lines were done with Rapidograph pens using black ink over the white sections. I started out with white ink for the black sections, but this skipped so badly and was so fragile to handle that I mixed up some medium gray using a combination of white and black. This was a little better, and was a little more subtle.

I clear-coated the whole model with PPG DAU75 automotive acrylic urethane with DXR80 hardener. This stuff goes on so easy it almost makes is worth the exorbitant price. Almost. It makes it very shiny, which isn't all that accurate, but it looks cool.

To finish off, I made some antennas out of .014 stainless wire (left over model airplane control lines...), and glued them to the fin tips. These are surprisingly tough, they get twanged all the time but they usually spring back.

Construction Rating: 3 out of 5

Flight:
The recommended motor for this model is the D12-5. Since I have a bunch of 24mm RMS reloads, I haven't tried it with the D12. I have flown it on the E28-4 (really 2) and it moves out quickly, and ejects at about 200 mph. After that I replaced the shredded plastic parachute with an Estes nylon 18" chute. The D15-4 works well, and has a nice high-enough flight. The E15-4 SU also works well, and gets it very high! The 18" chute is plenty big enough, and it drifts pretty good. The only damage I've had was from some kids finding and throwing it back and forth like a javelin into a gravel pile.

Recovery:
As mentioned earlier, the stock shock cord is laughable and was replaced. The 3/8 elastic seems to be plenty good. The stock chute is also OK if you avoid off-apogee ejection. This model also takes a lot of wadding and this leaves relatively little room for chute packing. The nose cone loop broke on the first flight. I replaced this with some .018 stranded SS cable threaded through some holes I drilled in the base of the nose cone. This seems to be holding OK. A potentially better way to go would be to glue a 1/8 ply bulkhead into the base of the nose cone. It needs some nose weight anyway.

Flight Rating: 4 out of 5

Summary:
All in all, a pretty good sport scale model as it comes, with the basis for a decent precision scale model with some modifications and cutting down the fins to scale size. Pros - flight performance, reasonable size, and price. Cons - tricky fin attachment, inadequate shock cord, lack of fin details.

Overall Rating: 3 out of 5