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REV 2.4 - Wed Aug 10 18:49:27 2011

Cosmos Mariner
P.O. Box 227, 1295 H Street
Penrose, CO 81240
(719) 372-6565
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SPECS: 18" x 1.637" - 8.6 oz
ROCKSIM FILE: MISSING - please submit here
SpaceCAD FILE: MISSING - please submit here

(Contributed - by Chan Stevens [Who's Who Page] - 01/17/06)

This X-Prize scale rocket showed good potential and an intriguing stealthy boost glider design, but save your money though, as it's a real clunker for flight.

Estes Cosmos Mariner X-Prize

Parts list includes:

  • BT-55 fuselage tube
  • BT-50 motor tube/pod tube
  • Laser cut fins
  • Molded plastic upper and lower halves
  • Plastic display nozzles/nozzle base
  • 18" plastic chute
  • Assorted centering rings and hardware details

The instructions are fairly clear with plenty of good illustrations. It's rated as a skill level 2 kit although I would have put it closer to a 3.

You begin with the construction of the pop pod. Nose weight is added in the form of 4 heavy steel washers on the forward end. On the aft end, there's a motor hook, block, and a wire assembly that serves to lock the elevators in place for flight.

The fuselage tube is simple, basically serving as a conduit to hold the pop pod. It gets a bulkhead on the forward end and is eventually mounted to the balsa wing assembly.

For a largely plastic body, this kit has a lot of balsa, adding both weight and complexity to the construction. There is a pair of matching wing halves, top and bottom vertical stabilizers, and a pair of elevators (one fixed, one floating). I goofed and didn't catch that the lower stabilizers are not symmetrical--there's a definite left and right--and I got them backwards initially. They have to be right or else the elevators and wire retention hook won't line up correctly.

The plastic fuselage halves are then bonded to the balsa frame. I couldn't get mine to line up very well and it took some trimming and a lot of gap filling before I was finally done. The instructions call for using a silicone adhesive. I used contact cement, which was just as effective but not as clean and easy to work with.

Finally, there is a display plug that has three nozzles. It's a nice visual touch.

Finishing on this kit is a bit of a pain. There's the matter of fairly ugly seams between the fuselage halves and there is plenty of exposed balsa grain. I applied a couple of light coats of primer, then sanded down to at least cover the worst of the grain. After that, I went with a tan finish paint, followed by a trim of gray, per the standard paint scheme. Masking off the gray is challenging, given the contours of the fuselage. Finally, there are a smattering of peel 'n' stick decals for trim.

Construction Rating: 4 out of 5

Estes Cosmos Mariner X-Prize

At nearly 9 ounces, I think the recommended D12-3 is overly optimistic. The Estes catalog claims altitudes of 250 feet. I think this rocket would benefit greatly from substituting higher thrust composite Es.

The flight profile is intended to have elevators locked in opposing positions during boost, giving it a roll to help stability. At apogee, the ejection charge forces the inner pop pod out, which falls under chute recovery. By removing the heavy pod, the glider is now light enough to fly and the floating elevator can spring into a lift-generating position. At least, that's the theory.

My flight lifted off fine although very slowly. It gently climbed with a slight roll. About halfway through the climb, it arced over and started a nose dive, crash landing under thrust. The pod deployed with a great deal of force, still on the ground. The impact cracked both fuselage halves, one section of balsa wing, and generally rendered this rocket to be retired from future service. A very disappointing performance.

The only feeble pro I can offer up is that a few of the kids at the launch thought the wreck was cool.

The cons are obvious: lousy flight, underpowered for the weight.

Flight Rating: 1 out of 5

There are very few rockets I've ever built that I felt were complete wastes of my time and money. This was definitely one of them. It might make a nice display model but not a good flyer.

Overall Rating: 2 out of 5

(Contributed - by Bruce D Canino [Who's Who Page] - 08/17/06) Estes Cosmos Mariner

The Estes Cosmos Mariner is a 1:67 scale version of the Lone Star Space Access team rocket plane for the X-Prize. It is a single stage D12-3 power glider with pop-pod on 18" parachute recovery.

1 main body tube with 24mm pop-pod insert. The pop-pod have centering rings that fit the body tube and 4 heavy washers for nose weight on boost. Flat wing glider is made from 6 laser cut wing panels. There are also 4 fins (rudders). The rest of the body is made from two large vacuumed form sheets of plastic. There are three display engine nozzles that come off for flight.

The instructions are easy to follow and the illustrations are good. You must have a good flat surface to build the wing. The wing consists of 6 large sections of balsa, 3 for each half of the glider wing. It is very important to have all pieces glue together flat. The hardest part was gluing on the two vacuum form body sections. The body sections didn't fit the assembly well. The instructions call for using a silicon adhesive. I used GE Silicone II. You have to wipe away any excess glue as you cannot sand it later. I was not impressed with the glue joint. If I had to do it again, I would use a thick super glue for plastics.

No special requirements for finishing. The balsa wings need a lot of sanding sealer to get smooth. The paint scheme is easy. There are a few stick on type decals.

Construction Rating: 4 out of 5

Estes Cosmos Mariner

The only recommended motor is the D12-3. The model boosts nicely with a slow roll during boost. It is important when flying to make sure that the elastic that pops up one elevator is attached well and when the pop-pod is inserted, the movable elevator is facing the opposite direction of the glued on elevator. This is what rolls the model during boost. Once the pop-pod ejects, the movable elevator pops up to get the plane into glide configuration. This glider is hard to balance. Even with glider at the specified balanced point, the glider stills stalls in flight. It is hard to test glide it since it a fairly heavy glider. It will take quite a few flights to trim out the glider. One person mentioned to me that even though it was stalling, it was one of the best glides he seen out of this kit.

I flew this model as a entry in SF/FF event at NARAM 48. On the first flight, the parachute on the pop-pod got tangled in the wire hook on the back of the pop-pod and never really opened, so it came streaming into the ground. The RSO DQed the flight as unsafe. The pop-pod with all those washer is very heavy, so it is important safety wise to make sure the chute will always open. On the second flight, I got rid of the Estes supplied chute and use a nylon chute of the same size. I also shortened the shroud lines and taped them to the pop-pod way from the wire hook in the back so there was no chance of them snagging on the wire. On the first landing, both wings cracked down the wing grain of the balsa to a point outside the lower rudders. This was repaired with super glue and flown again. Admittedly the ground at NARAM was hard packed and there was no grass to cushion the landing. I am sure landing on macadam or concrete would also be very bad for this glider, so avoid flying it near paved areas.

Flight Rating: 4 out of 5

I like this glider even thought it is on the heavy side. Most of the glider seems right on except for the back where the engine goes. On the picture on the package, it has the engine sitting inside the three display nozzles, however, when you build it, the display nozzles come off and leave an ugly gap where the body wrap doesn't quite fit around the body tube. I am guessing the original plan was to have the display nozzles and backing on the pop-pod for flight but was given up during the kit release. I think it is possible to grind out the display backing to fit the pop-pod with the display nozzles but that is something for another time.

Overall Rating: 4 out of 5

[Submit your Opinion]

07/10 - "This is a very delicate model. The balsa for the frame is only 1/16-inch thick. It splits very easily when not handled carefully before the body shells are attached. Like Chan, I used contact cement to attach the body shells (specifically, the non-toxic water-based variety that doesn't attach the plastic). This stuff holds the parts together very well but you must be very precise when actually joining the parts. I agree that this model is more "show" than "go". It just doesn't have the structural strength to handle any kind of adverse landing, let alone landing on any kind of hard surface." (D.S.M.)

07/06 - "I think the reviewer was far too nice about this bird. First of all, Estes lists this kit as a skill 2 IIRC and really ought to be a skill 5. The plastic body pieces fit together poorly and the instructions were rather cryptic as to exactly how they were to line-up before trimming the edges. Not only that, but the instructions suggest silicone glue for securing the plastic to the balsa. After mine crashed, I was able to easily pull apart the plastic from the balsa. Bad choice of glue which probably should have been epoxy. I only got one decent flight out of mine and that was terrifying at best. The motor pod ejected with a gigantic pop which vaguely resembled a cato and the shroud lines ripped off the parachute almost every time I launched it no matter how it was packed. In any amount of breeze it weather-cocked like no other. If you are an LSO and someone shows up with one of these in your flight-line be sure to have them place it on the “away” pads and make it a heads-up launch. This kit is a flying piece of garbage and I am sorry I wasted my money on it." (D.A.B.)

05/06 - "Comments: After reading this review, I have decided that my Cosmos Mariner will become Display Only model and the beast's innards will be 'reassigned' to a freelance scratch-built boost glider project loosely based on Convair's XB-53 design proposal, with a sci-fi twist. Which, it seems, may have a better chance of success, even if it might be a "roll-of-the-dice" for either model's chance of coming back alive. later, F.S.W." (F.S.W.)

[Enter Rocket Specific Tip]

07/10 - "If you want to use sanding sealing to finish the exposed parts of the balsa frame, do the seal-sand-seal-etc. process before attaching the plastic body shells. The plastic will likely deform badly if it comes in contact with sanding sealer." (D.S.M. )

07/10 - "When assembling the back plate with the display nozzles, use contact cement instead of the recommended Testor's plastic cement. I tried both solvent-based kinds of Testor's cement (tube-type and brush-on type) and neither bonded very well with the plastic. The pieces would appear to be attached, but would snap off very easily when handled. Contact cement yielded a solid, strong bond." (D.S.M. )

07/10 - "When attaching the plastic body shells to the balsa frame, attach the bottom shell first, not the top shell. The bottom shell has a shaped chamber that fits very precisely into the balsa frame. This needs to be in place to accurately position the nose of the top shell whose positioning is relatively ambiguous." (D.S.M. )

[Enter Flight Log]
Date Name Motor Ejection/
Wind Notes
11-11-2005 Donald Besaw Est SU D12-3 Just Past (1-2sec) 0-5 mph winds II - Nice first flight of the CMII. Wobbled around quite a bit during boost but got up high enough to kick the pod and start a rather poor glide, lots of stalling noticed, more nose weight should fix that. No damage sustained.
11-25-2005 Donald Besaw Est SU D12-3 Just Past (1-2sec) Calm II - Yeah, finally got a successful flight from this thing. Nice rolling boost to maybe 150-200 feet. I had added quite a bit of nose weight which gave me a nice glide that I can live with. No damage.
12-14-2005 Donald Besaw Est SU D12-3 Just Past (1-2sec) 5-10 mph winds II - Very nice flight. Glided quite a distance before making a gentle landing. No damage.
02-10-2006 Donald Besaw Est SU D12-3 Just Past (1-2sec) 0-5 mph winds II - Great flight and glide. Unfortunately the pod chute shredded and the pod tumbled down and received a minor tube crumple and I noticed some minor melting from the motor exhaust. Nothing major.
08-26-2006 Donald Besaw Est SU D12-3 Just Past (1-2sec) 0-5 mph winds II - Good flight, typical arc during boost, violent pod ejection. Fair glide, descended rapidly and landed hard which ripped off both bottom vertical stabilizers, already fixed. No other damage.
09-02-2005 Donald Besaw Est SU D12-3 Very Late 0-5 mph winds RIP - Very ugly flight, took off, arched over and flew horizontal across the sky, turned nose down at burnout and crashed, casing serious damage to the nose. I ain't gonna bother fixing this one!!! Status: Not Repairable
03-12-2006 Dave Brunsting Est SU D12-3 Very Late 5-10 mph winds - Horrible flight. Ejected with the nose cone down and shot the glider down so fast that it didn't have time to recover and it crashed. Worst flying boost-glider I have ever seen.
08-04-2006 Bruce Canino Est SU D12-3 Just Before Calm Event: NARAM-48
- Parachute tangled in pop-pod and streamed into the ground. DQ. Glider was stalling. Both wings cracked on landing following the grain.
08-04-2006 Bruce Canino Est SU D12-3 Just Before Calm Event: NARAM-48
- Pop-pod deployed parachute this time. Loop after ejection and then settled into a glide. Still stalling with more nose weight.
07-11-2009 Edward Chess Est SU D12-3 None - Unstable 5-10 mph winds RIPEvent: Kishwaukee Park
- Unstable first flight. Power pranged. Nose area destroyed. M. Bundick will try to repair. May need additional nose weight. Status: Lawn Dart
05-17-2020 Gregg Discenza Est SU D12-5 Apogee - Perfect 0-5 mph winds - Built this thing before I found this site. Had I read some of the reviews, I would never have done it. First flight OK, some corkscrew at liftoff, pop pod kicked out, and the glider landed about 50 yds from pad
05-17-2020 Gregg Discenza Est SU D12-5 Just Before 0-5 mph winds RIP - Second flight, far worse, aileron kicked up just off the pad, rocket went ballistic, pop pod ejected about 5 feet up, the glider hit hard and cracked several parts. Status: Not Repairable
09-19-2009 John Lee Est SU D12-3 Very Late 0-5 mph winds RIPFlight PictureEvent: Alamo Rocketeers Monthly Launch
- Arced over and hit the ground. Ejection occurred on the ground. Bonus ejection charge threw the motor pod back 70 yards. Status: Not Repairable
01-15-2006 Chan Stevens Est SU D12-3 Very Late 0-5 mph winds RIP - Unstable, crashed landed under thrust Status: Lawn Dart

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