Any Estes Cosmos Mariner Fans, Flyers or Experts?

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Well-Known Member
Jan 17, 2009
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Woodstock, IL
One of our members power pranged his Cosmos Mariner yesterday. The builder is an excellent craftsman, and has a 90+% success rate on his flights. The model looked to me to be quite well built, with no deviations from the Estes instructions. But it power pranged anyway.

He's given up on the bird, but I can't resist a glider challenge.

I'm attaching two pictures of the damage.

Can I get some suggestions for the repair and any good mods to make to the bird to get it to fly from any Cosmos Mariner flyers out here?

CM 1.jpg

CM 2.jpg
Looks similar to the damage to mine... I cut a new piece of scrap balsa to replace the splintered wood and got replacement vacuformed shell parts from Christine @ Estes. The repair glider works (hand tossed), and i'm going to fly it next weekend, weather permitting. If it flies, I'll paint the new shells. If it doesn't, retirement.
Bunny, you know better. ;) Call Christine at Estes and have them 'replace' it. Why spend your hard earned dosh on something that's their fault to begin with. You've got the pics, proof enough.
My Cosmos Mariner is still in my build pile. Why? My Estes foam space shuttle power-pranged on flights 1 and 2. My Estes SRX power-pranged on the first flight. They are both in the junk pile now. I can't see that it's worth the building time to watch another $40.00 nosedive under power.
Some people seem to have got these pieces of junk to fly. What's the secret? Ted
Sorry to hear about your crash but that is what these things tend to do. Mine was to maiden this weekend and it actually crashed before it flew. The movers (in Miami) folded it to fit into a moving box. I sort of restored it, but the internal structure is damaged.
Dus to bad weather the launch was canceled, so i made a stopmotion movie with lego men. That is going to be continued, probably with a not so happy ending for the pilot....:dark:
Always thought this thing would look pretty cool stacked Shuttle-style on an appropriately-sized tank and SRB's and flown as a BG. I bought 2 with the intent of doing that project .... it's still on the some-day list though.
There are a couple of videos on youtube (search Estes Mariner). One is a spoken word video, and the guy (Paul. I think he was a member of the forum a while back) says it's the worst rocket ever. Another one the launch rod takes off with the rocket. I think that one was also taken by a member of the forum if I recall correctly.

That being said, I have been tempted so many times to buy that rocket, but just stuck with my good ole Scissor Wing Transport instead.

Saw one fly at NSL2007, and it was beautiful. Launch was straight and she floated like a feather on recovery. Can remember the fellows name but he had the touch.
It looks like a very nice model with great workmanship, but my advice, fix it up and then keep it for display only.

My son and I built one and at least we were able to get 3 flights out of it. We too had one where the launch rod went with it. Our highest altitude may have been 50 feet.
Not sure about the NSL build, but you might hit up Kevin Johnson for some advice. He not only got one to fly stably (TWICE!), but modified it for R/C.

Personally, I'm 0 for 1. Built it stock, "power pranged" on a D12, though it's so friggin' heavy power prang is a generous term. When I recovered the remains, I boxed it up, shipped the whole thing back to Estes, and said if they sent me another one/replacement that would be the end of my relationship with them. Looks cool, flies like poop, rally poor overall engineering.

The story did have a happy ending--Estes did wind up sending me an Omega DD and a bunch of motors.

If you do decide to repair it, which wouldn't be all that tough if you got replacement skins, I'd consider it a display model. Troll around the forum here and at YORF and you'll find at best 1 out of 10 people are satisfied with the flight of this beast.

This rant is coming from a guy that almost never pans a model rocket--built over 500 commercial kits now, can think of maybe 2-3 I would not gladly build all over again.

--Chan Stevens
Bruce Canino flew two flights at ECRM in the Concept Scale event with his CM free flight model. Seemed to work great both times (kicked the motor casing on flight 1) although to me the ejection of the power pod seemed way more enerjetic than it had to be.

I RC'd mine for two reasons- the first being that when I was putting it together the fit on the power pod was so freaking tight that I would have had to cut away parts of the washers and front centering ring to get it to work properly. The second reason was becasue it was cool. :)

As for repairs, Bunny, I'd see if you can get the replacement body shells from the big E. If the wood skeleton is intact you should be able to repair it fairly easily. Take a look a the pod and make sure that it slides easily in the inner tube. Double check the position of the movable flap and make sure it's able to deflect downwards far enough to counter the one that's set in the up position. Without that it will definitely arc.

So does anybody know WHY these things fly so poorly and what might be done to make them work better? Is it an issue with weight, or just poor aero?
So does anybody know WHY these things fly so poorly and what might be done to make them work better? Is it an issue with weight, or just poor aero?

Yes to both. Aerodynamically, it's a flying brick like the shuttle, generating little or no lift. Engineering-wise, it's a very heavy brick, using thick balsa, plastic skins over the whole top/bottom, a stuffer tube with heavy washers to push the CG forward during boost, etc. IIRC the total stacked up weight even exceeds Estes' maximum recommended liftoff weight for a D12. It could really use a weight reduction program, starting with a frame assembly rather than solid balsa/plastic.

--Chan Stevens
I've had mixed results with this model and I've built a total of two of them.

The first one basically rekitted itself on the first flight and the second one has flown somewhat better but the last flight it landed hard and snapped off both bottom vertical stabilizers.

Overall it's a really crappy kit and I definitely would not build another one either. Heck, I might eventually purge mine from my fleet by either flying it on a D11-P and let it take a death dive or fly it on an AT SU E30T and let it either CATO on the pad or watch it self destruct in flight!!!:D
Ah the excitement of the loud pooom when it kicks out it's engine pod is a gas. It's brief glide is rather scifi looking as well. I think folks should try one :)

mariner up.jpg

mariner glide.jpg

mariner impact.jpg
Well, yesterday was planned to be the big day for the CM maiden flight. But, too much wind, 5 Bft (30-39km/h) windforce.
There was a lot of high grass near the launch area. So i decided to give it a try and handtossed it in the wind. It sort of floated and landed very gently. I did not expect this and was very impresed. So know i am a lot more serious of getting this one to fly (change of mind since my prevous post). I made one change to the cosmos mariner, and that is that i increased the size and the hieight of the upward wing tip. Read something in harry stine or on wikipedia that that helps in dehydral effects.
So my question is that if the bird built well enough, what else (except for praying) can one do to in terms of preparation to make this one fly like Fred42's CM? So what wind conditions, how to prevent from arching, etc?
So as a bit of refresh, what are the tricks people think would make this baby fly well . . .
Well I think one needs to
Balance with careful hand tossing.
Pack the chute well to avoid the engine pod from snagging.
Use a long long launch rod. I use a mantis pad which is longer then a standard estes rod.
I launch mine in zero wind only.
Some really great folks don't like this bird so hope for luck as well maybe :)
I would hasten to add that a successful glide with this bird is brief as it does not get high , dives at a steep angle as well:)
I can honestly say I've never seen one of these fly poorly (that wasn't due to pilot error). Kevin's flew fine right up to the point when the RC failed. Couple of flights at NARAM (not sure who's), and one in my backyard. They all flew fine, albeit a little low.

Fred's points are spot on. I'd recommend you build it, balance it, throw it until it flys, then and only then paint it. Throw it again and micro adjust due to the paint weight. It will fly like any other gliders out there. It flys a lot like the real shuttle.

shipped the whole thing back to Estes, and said if they sent me another one/replacement that would be the end of my relationship with them--Chan Stevens

Ohhhh....this sounds like rocket baiting blackmail...:rolleyes: Chan, seems your track record with boost gliders isn't so good....didn't you have a problem with a shuttle stack?:p
thanks for the advice, mine was already painted, so I'll sit and wait for calm weather.
The thing you got to remember about the CM is the model really needs to spin on the way up. If the model just arcs over and powers into the ground, You don't have the spin elevators set right. The CM is also very prone to weather cocking so try to avoid windy days.

Make sure when you place the power pod in, one of the little metal arms is under the fixed elevator and and the other is holding the movable elevator at a equal angle in the opposite direction. The little metal arms are flexible and will bend. Depending on how much pressure is on the movable elevator, you made need to over bend the arm to hold it at the proper angle.

Also getting the chute to deploy right is kind of a art too. I find taping the end of the chute on the front of the pod keeps the chute away from the little metal arms and fouling on them. Make sure the power pod slides easily in the motor tube. I found placing graphite on the washer helps. Also make sure the chute not binding in the washers.

I did get to see K Johnson R/C CM after it was crash and was intrigued by it. I'll have to build one.
I posted the photos of the final RC gear installation over in the YORF thread.

Mine maidenen today.
I think I followed all the advice i could, and made one modification. During my move from the USA to the netherlands, some Miami Mover employee basically folded it up so taht it would fit in a moving box. I was able te restore it and give it bigger winglets for som extra stability. Well, those worked. The handtosses showed great stability (I did my tests in July with beaufort 5 windforce and it flew). I wasn't able to get both ailerons deflect at the same opposite angle, so that was a little bit of a worry to me, hoping it would not arc too much during boost. So basically, I tried to built it right, balance it the right way and i tried not too forget the preflight preparation. The RCO refered me to the far away launch pad...
The boost was more or less straight up with a nice slow roll, and a bit of an arc against the wind, but not too big. Then with a loud bang the pod came out and deployed, AND the thing flew! It was a great side. About 2/3 of the flight it stalled, it dove down and pulled up 2 meters above the ground and then landed. Not too bad. Because of the landing it had some sand at the nose and i decided that that would be a nice addition of weight to stabilize it a little more. Basically i was really proud, that i was one of the few that got a nice flight out of it. :D
Second flight: boost went more or less the same, there was a little more wind, but it stalled more! That was something i did not expect! The CM landed in the nicely high grass and basically looked like the CM in the first post on this thread. Cockpit gone, the blocker for the pod ejection gone, one of the washers and the plastic ring, gone as well, and the wood structure is more damaged than before. Everything in that area was glued with epoxy. I suppose that it stalled more, because the cockpit was gone and therefore there was less weight in the nose. So in this thread we're back to square one.
Both flight were video taped and photographed, once i get them in the mail i will post them, that is some one is interested.
I think it is time to send an email to ESTES, again.
what about useing lighter balsa. triming or sanding the power pod so it move freely or with slight force and adjusting the spin tabs for a stronger spin. This is a kit I always wanted but never grabed. or just for fun kit bash a shuttle kit for the stacks and mount it on that makeing it a shell only and the stacks the main. then its just a glider and the stacks can be made to take it higher.

just a thought