Mars Rocket 2.6

Designed and started building a "classic"-styled 2.6" diameter rocket with a three E-engine cluster mount. Rocksim has it at 1600 feet with E-9s and 3800 feet with Aerotech F-32s. I'll wait until its all together to confirm its weight, but I think that a 36" parachute should be just about right.

View attachment Mars Rocket I.pdf

Elon said:

Designed and started building a "classic"-styled 2.6" diameter rocket with a three E-engine cluster mount. Rocksim has it at 1600 feet with E-9s and 3800 feet with Aerotech F-32s. I'll wait until its all together to confirm its weight, but I think that a 36" parachute should be just about right.

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I like the retro look.

The ribs you added to the ends of the fins for strength is not only a very good idea, it also lends more of a Si-Fi look to the back end of the rocket.

The fixture your using for glueing up the fins looks like it's more then up to the task. It looks great, make it yourself?

The F32 has a built in thrust ring on the case. You will not be able to fly that motor cluster in your current MM configuration. There is no room for the thrust rings.

I have the same problem with my Fliskits Richter Recker. The 3 cluster MMT's butt up against each other so we cannot put those motors there unless we either trim off enough of the rings to permit the fit or redo the MM with enough space in between to allow the 3 cluster F32.

See the pic of the F32 with the thrust rings visible.

Other than that, love your design and the fin alignment jig! Purchased or Home Produce?

Thanks guys! I made the jig last Saturday based on the Apogee "guillotine" jig, but designed to take up to 3" tubes. I also have extension plates so that you can reach down all the way to the tube if you have to (I'll need to use them for the canards.)

If one filed a flat spot on one side of the thrust ring on the F-32s would they fit then? Thanks for the note - you may have very well just saved me a bit of change and some disappointment, though I'm not yet certified to launch that much propellant to almost 4,000 feet. I'll have to build a single motor 29mm for that.

- E

I didn't originally intend to include the reinforcement, but the fins were too floppy not to find some solution. They may very well still flutter too much, but we'll see soon enough!

- E

Wow! Dig the look.

Elon said:

Thanks guys!
If one filed a flat spot on one side of the thrust ring on the F-32s would they fit then? Thanks for the note - you may have very well just saved me a bit of change and some disappointment, though I'm not yet certified to launch that much propellant to almost 4,000 feet. I'll have to build a single motor 29mm for that.

- E

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You are welcome.

I also considered filing off edges but don't know what that would do to any Aerotech warranty if you had a CATO of some kind. Also, would it weaken the case? There may be other concerns someone may come up with as well, like overall safety of altering a SU case?

It looks like a rocket! I still have to fillet the fins and canards, install the baffle and recovery system, and of course, paint it. Also, I have yet to determine exactly where the CP is if it needs nose weight. It sure is bottom heavy, and will be much more so with the engines in.

Elon

I hope you are using a nice size chute...

Those fins look like they will snap for sure if they don't sit down soft.

Awesome design and really great build so far!

Thanks much. The fins may be a bit delicate. I think a 36" chute will be required, but I won't pick the chute and install the baffle until after the rocket has been weighed. I thought I might use a small external cord to get the rocket to come down sideways rather than straight down tail first. Thoughts on parachute size, brand or shape?

Elon said:

Thanks much. The fins may be a bit delicate. I think a 36" chute will be required, but I won't pick the chute and install the baffle until after the rocket has been weighed. I thought I might use a small external cord to get the rocket to come down sideways rather than straight down tail first. Thoughts on parachute size, brand or shape?

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I used a 36" military surplus chute and it has the drag of a 44" chute. I think the CD is somewhere around 1.0- 1.5? Not completely sure? You can get them for a lot less then most places. They don't come with a bridle so you may want to have someone install one for you with a barrel swivel.

You can get them at Aerocon Systems

https://aeroconsystems.com/cart/all-parachutes/36-inch-white-parachute/

You can also dye them whatever color you want...

Thanks Dan. I checked out the site and your description of your para there. It looks perfect. I'll give them a call this morning when they open. How much did you pay with the Kevlar bridle and barrel swivel?

Very nice....
We love retro.

Elon said:

Thanks Dan. I checked out the site and your description of your para there. It looks perfect. I'll give them a call this morning when they open. How much did you pay with the Kevlar bridle and barrel swivel?

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I contacted Scott @ K&S and he did the work for me .. I hate to quote what he charged me for the bridle, all I can say it was very reasonable and he does exceptional work. I'm very happy with the service I received from him.

I had my hardware already, but there are many online stores that sell it. Topflight for one is probably one place to go to. I used a 350lb swivel and a 1/8" quick link. Works great!

Layne, thanks much!! Your designs were a huge inspiration for this build!

Elon

OK I want your building jig, supply measurements and detailed photos. (does Jedi hand wave) Neat build BTW

TA

Cool look. Hate to see those fins snap.

Would this help?

External shock cord mount at the tail of the rocket. Could attach it to or near the base of the fins. Even better would be on the motor mount coming out between the engines. Can put a little loop there, put a snap swivel on the end of your cord, and unhook it and completely hide it inside rocket when on display.

Rocket descends under chute and impacts the ground with the nose end of the body tube first.

Just an idea.

Babar, you've exactly the idea! The Pemberton Bucky uses a little external cord to level the ship as it descends. The wire is attached to a reinforced hole at the front of one of the fins and is attached the nose cone. If I had planned ahead rear ejection would have been a possibility as well. It may simply be, of course, that the thing is just designed to delicately...

BABAR said:

Cool look. Hate to see those fins snap.

Would this help?

External shock cord mount at the tail of the rocket. Could attach it to or near the base of the fins. Even better would be on the motor mount coming out between the engines. Can put a little loop there, put a snap swivel on the end of your cord, and unhook it and completely hide it inside rocket when on display.

Rocket descends under chute and impacts the ground with the nose end of the body tube first.

Just an idea.

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Or maybe this....

I think Rear ejection would just have caused it to swing back and forth wiping out the tips one by one. Seems to me, Your idea of a level recovery bridal is probably a good approach.

Check out this: https://www.rocketryforum.com/showthread.php?t=32551

A .pdf of the jig I built is attached. I have little extension plates that get attached to the bottom as well that extend the jig all the way down to the tube if need be for small fins.

Elon

View attachment Fin Alignment Jig Plans.pdf

Pem Tech said:

Or maybe this....

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Precisely that.

- E

I like it! What an awesome design! Nice shop, too!

Thanks! I try and keep it clean. Check out my website (www.thecustomdistrict.com) or our Facebook page (the rockets are appearing there with the hope that a few non-rockteers might get into it - so far I've managed to recruit about 6 local folks into building rockets for an impromptu launch party.) I'll pretty much design and make anything.

Finishing is underway...

Colors?

I'm thinking just silver since the form is so strong.

judo said:

Colors?

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white with orange fins or silver with orange and spray paint the tip gloss black.

Black BT and nose cone with red canards and silver fins would look pretty good, IMO.
How much does it weigh so far? I heard that Estes is coming out with the E12 sometime this year, maybe you could fly it on those (though I'm not sure how late in the year the release date is. Could be a while).
Been lurking on this thread for a while. Great design and good job building it!

Thanks much! I'll have a weight tomorrow. Here's the scoop on the Estes BP E12:

"Hi Elon…thanks for your email and inquiry regarding our engines. We are still testing the E12’s and have no firm production date set. I would suggest checking on the website in another 2-3 months for the actual shipping date.
Regards,
Mike Fritz
Estes-Cox Corp."

Rocketbuilder said:

Black BT and nose cone with red canards and silver fins would look pretty good, IMO.
How much does it weigh so far? I heard that Estes is coming out with the E12 sometime this year, maybe you could fly it on those (though I'm not sure how late in the year the release date is. Could be a while).
Been lurking on this thread for a while. Great design and good job building it!

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