Rogue Aerospace Standard ARM 45

Rogue Aerospace - Standard ARM 45

Contributed by G. A. Dean

Construction Rating: starstarstarstarstar
Flight Rating: starstarstarstarstar_border
Overall Rating: starstarstarstarstar
Manufacturer: Rogue Aerospace

Standard ARMBrief:
The Standard ARM kit from Rogue is a single-stage sport-scale replica of the Navy's AGM-78 "Standard" missile. It's loads of fun to build, and flies very nicely on 24mm, D12-5 motors. Rogue lists the kit as a "Level 2", which I believe is accurate. Some modeling experience will help, but the kit poses no special problems or challenges. What it does offer is an unusual variety of building experience that is a nice change from the predictability of most model rockets these days.

Construction:
This kit is an adaptation of an old kit from MRC. Rogue acquired rights to the kit from MRC along with their inventory of parts. Rogue has apparently made some alterations to the MRC kit, but it's basically the same rocket.

The kit arrived very quickly from Rogue via priority mail, as is their custom. All parts were present and in good shape. The materials are all high-quality, and one is immediately impressed by the size of the kit. The body tubes are 45mm (or 1.75 in.) in diameter, and have a nice, sturdy feel. The kit includes a variety of materials; paper for the tubes and baffle unit, balsa strakes, plastic nosecone, main fins and fin/connector tube, nylon chute, and Kevlar® and elastic shock-cords.

Construction:

The body of this rocket is built using five separate units making four tube sections. The main body tube is topped by an "upper body tube" that will contain the parachute. It's connected to the main tube by a tube coupler that doubles as the ejection baffle (what BAR's like to call a "Centuri baffle"). At the other end a plastic fin-mount ring acts as fin mount, engine mount and connector between the main body tube and the short "lower body tube".

Construction starts by marking the fin and launch-lug locations on the main tube, using the fin-mount ring as a guide. You will need to install this ring later in the construction process in exactly the same orientation, so be sure to mark the reference lines as directed in the instructions.

Once the tube is marked you move on to the "balsa" part of this kit, the long "strakes" that are characteristic of kits based on the AGM-78 missile. I used yellow glue to secure the strakes to the tube. With that done, it's time to assemble the engine mount. You start by tieing a loop into the Kevlar® tether, as the tether will be secured to the engine clip. The engine clip fits into a slot in the engine tube as with most Estes kits. The tether is looped around the clip where it enters the tube. Die-cut centering rings are then glued to the ends of the plastic fin-mount ring. I used slow cure CA for this plastic-to-paper join; its "tricky' only in that the centering rings need to be carefully set flush with the tube. Once the glue had set I lightly sanded the edges of the rings in a few places to get everything nice and flush. The engine tube, with the engine hook and thrust ring installed, slides into the centering rings normally and is secured with a "generous" amount of glue.

Standard ARM The baffle unit is very simple. Two die-cut baffle disks glue to the ends of the paper coupler tube. Again I sanded to make the edges of the disks flush with the tube.

At this point the rocket's five-part body goes together. The only tricky steps are to make sure that the fin mount is correctly aligned when it is glued in place (and that its at the correct end of the main tube!) and that the Kevlar® tether is fed forward through the main tube and through the holes on the baffle unit before the baffle is glued in place.

With the body completed the main fins are attached. These plastic fins have a small tab on the root edge that fits into a slot on the fin-mount ring. This slot is nowhere near a "through-the-wall" mount and will provide little extra support for the fin. but it will make it much easier to place and align the fins correctly.

I needed to trim the tabs and clear out the slots slightly with my hobby knife to get a good fit. Take care not to get glue in these slots when you assemble the rocket body. The tabs have to go fully into the slots to get the rest of the root edge firmly set on the tube. I used CA to initially set the fit, and then went a bit beyond the instructions and used 15 minute epoxy for the fin fillets. Be sure to sand the body tube along the area where the fins will attach before you glue the fins in place. This will give the glue a rough surface to adhere to and greatly strengthen the connection.

The fins are molded with a nice, "military-style" taper on both leading and trailing edge, and a thin line marks the edge of the taper. I found it difficult to sand my fin fillets smooth without marring the surface of the fins and removing the detail line. Be sure to make your fillet as smooth as you can when you apply it to reduce the amount of sanding required.

The final assemble is pretty straightforward. Another loop is formed in the end of the Kevlar® tether, which runs all the way through the rocket from the engine clip out the upper tube. As this is a fine Kevlar® thread I 'painted" the interior top inch of the upper body tube with thin CA to strengthen it against "zipper" damage. The elastic cord is secured to the nose cone and given a similar loop in the free end. This cord seems quite short, but I judged it adequate. The length seems designed to keep the nosecone from banging on the body tube during recovery.

The chute (18'' nylon) is secured to both the Kevlar® and elastic tether loops and in fact forms the connection between them. I'm not sure how I feel about this arrangement. One could also loop the elastic cord and nosecone to the Kevlar® before securing the chute. I'm also a bit concerned that there is no elastic between the chute and the Kevlar® tether. A high-speed deployment could subject the chute to some high forces or induce a zipper on the body tube. So far I've had no problem, however.

Finishing:
Standard ARM The spirals on the Rogue T-45 tube are very fine but apparently deeper than they look. I usually fill with Elmer's Fill'N'Finish, but I decided this time to let the primer do the job. That turned out to be more work than I expected. It took several coats with sanding, and I think I would have achieved a better result with less effort with FnF. I would recommend filling and sanding the balsa strakes before they are glued to the tube. The wood-grain runs along the strake, and if the strake is in-place on the rocket your sanding also runs along the grain, and it's tough to get a smooth surface.

I used gray Krylon primer topped by white gloss. Then I painted the nose-cone gloss grey. Rogue suggests a "tan" nose-cone (photo's of the real missile show it with a coppery-colored nose which looks great) but I did not have any such color in my paint drawer so I went with grey.

Rogue provides a variety of decals for the kit but leaves the decision on where to place them up to you. I used most of the decals (I did not use all of the decal "rivets") and added a few extra decals from a Rogue AGM-3500 Peregrin kit I built earlier. I finished it off with glossy clear-coat. The gloss finish is not traditional on military missiles, but I thought it looked sharp. The end result is a very nicely proportioned, good-looking rocket.

My rocket comes in heavier than the manufacturer's quoted weight and the sum of the individually weighed parts. I think the epoxy fillets and the many coats of primer are to blame. I think I overbuilt it, to tell the truth, and if I build another I will use lighter fillets and fill the grooves with FnF before painting. The RockSim file provided with the review uses accurate weights for each part and an adjustment "mass" to reflect the actual completed weight and CG of my model.

Moderate differences in total weight don't impact the flight altitude of this rocket much. A heavier rocket will accelerate a bit slower but coast a bit longer, ending up at about the same height. Obviously you will need to check CG/CP position and stability, but the design seems to be comfortably stable so long as you stay reasonably close to 'stock'.

Construction Rating: 5 out of 5

Flight:
I have only one flight on this bird at this time. I sent it up at a club launch this weekend on a D12-5, the only motor recommended by Rogue. This motor is a very nice match for this airframe; delay is just right, and the altitude , according to RockSim, is close to 700 feet. A nice comfortable altitude that keeps the rocket in sight and the recovery close by. The winds were blowing at the time of launch, certainly over 10mph and perhaps 15mph, but the Standard didn't seem to notice. There was a very slight turn into the wind and then a straight boost to apogee. I don't think I got all of the predicted altitude, but it felt plenty high for the conditions.

Recovery:
The deployment was just as the rocket turned nose down. The chute did not open fully, but the rocket descended at a reasonable speed and considering the winds, was probably better off.

It landed about 150 yards downwind without damage. The baffle did it's job well; the chute had some soot on it but no melting or scorching. There was lots of debris from the ejection charge in the baffle after the flight, but a few shakes got that out (those D12's leave a mess behind!)

Although I only have the one flight I'll give the rocket a 4 1/2 rating as the flight was a good one and I have hopes for many more such flights. Seems like a good dependable design.

Flight Rating: 4 out of 5

Summary:
My only complaints are minor. The launch lugs are for a 1/8'' launch rod. This rocket is big enough to blow around on the pad and I would have been more comfortable on a heavier rod (but the launch did go just fine, after all). The shroud lines for the chute are a loosely wound yarn or string that tends to catch on itself and clump, unlike Kevlar® thread that runs over itself very smoothly. I think this contributed to the tangle that caused my chute to partially fill. I expect that with careful packing the chute will work just fine. It's a minor point, but something to think about.

For our field size the D12 gives an ideal flight. I believe the rocket would fly well on composite D or lower-thrust E engines, like the E15 or E18, or even the F12. RockSim predicts flights of 1,600' or more. The kit feels sturdy enough to handle the peak accelerations from those motors (which are close to the D12 anyway), and the longer burn ought to give an exciting flight. With some modification you should be able to use the long-burning Estes E engines. I would be careful using motors with a higher peak thrust as the increased Gs and top speed might overwhelm the surface mount fins. The more daring among you may want to give it a try and post the results for us here.

If your rocketry is limited by your flying field or your budget, you are probably getting bored building Estes and Quest kits. They all go together pretty much the same way. This rocket is a great "step-up" in kit quality, rocket size, and building fun. This kit will not expose you to high-power construction techniques, nor will it stretch your modelling skills with difficult challenges; but it's not going to bore you either. You have to *build* this kit, and pay attention to what you're doing. It all goes together well, however, and the result is a good-looking and great flying rocket.

Overall Rating: 5 out of 5

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