3D Printing 2x and 2.7x Mars Landers

After seeing the original sized Mars Lander on Thingiverse I’d always thought about scaling it up. Once the 2x was posted I printed one up and then scaled it up to the maximum capacity of my printer, a Creality CR-10s pro, which came out to be 2.7x.
I was hoping the 2x could be built light enough for non waiver flights but it comes in at almost 3 pounds as printed without any nose weight or motor mount so flights will be G and up. Still need to sort out mounts and such.
Not quite sure if the 2.7x will wind up being flyable or display but it sure is impressively sized.
All three for comparison.
This was my longest print yet. 2.7x ascent stage at 115hr!

John Cummings said:

This was my longest print yet. 2.7x ascent stage at 115hr!

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Do you run a UPS, or just trust the utility company? Curious.

The CR-10s pro has power interruption recovery so no worries but fortunately didn’t need to test that option.
My worries were more of the “tripping over the cord” type power interruption....

John Cummings said:

The CR-10s pro has power interruption recovery so no worries but fortunately didn’t need to test that option.
My worries were more of the “tripping over the cord” type power interruption....

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That only works if you have not hooked up Octoprint.

cwbullet said:

That only works if you have not hooked up Octoprint.

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So you connect a Raspberry Pi and Octoprint to monitor your prints remotely and then lose the resume function...? That's good to know... I've been considering doing this too but may have to also invest in a good UPS although I am fortunate to live in an area where power outages are rare.
More investigation will be necessary before I make the Octoprint leap.

Thanks,
John

I hadn't thought about it before, but now that it's brought up it seems kind of crazy not to put one of these things on a UPS, given how cheap they are.

That 2.7x Mars Lander is a big boy, looks great!

I wanted to do a 2X but my local library’s printer can’t do the top piece as it’s too tall.

Be careful with your motor choice. I was a little too aggressive on my first flight on the 2x. Mars Lander tried to revert to filament mid flight

alexzogh said:

View attachment 389652 Be careful with your motor choice. I was a little too aggressive on my first flight on the 2x. Mars Lander tried to revert to filament mid flight

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I’ve always wondered about that. Most filament 3D prints I’ve seen are fairly fragile.

Some plastics can benefit from an acetone vapour treatment to increase strength. Not sure if that is applicable to PLA though. I use it on ABS.

OverTheTop said:

Some plastics can benefit from an acetone vapour treatment to increase strength. Not sure if that is applicable to PLA though. I use it on ABS.

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Not applicable to PLA.

However, it has always been my understanding that PLA has better layer adhesion than ABS, and doesn't really need that sort of treatment. Of course, the acetone vapor treatment also does a great job at smoothing out the surface of ABS prints (again, not PLA).

It has never been my impression that filament 3D prints are fragile when printed correctly, particularly PLA which is rock hard (but also heavy and a bit brittle).

Did you post your files to thingverse?

neil_w said:

It has never been my impression that filament 3D prints are fragile when printed correctly, particularly PLA which is rock hard (but also heavy and a bit brittle).

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I’ve noticed this as well. Always heard people saying how much stronger ABS is than PLA and while I’m not disputing that it is, PLA seems quite strong and prints sooo nice IMHO.

These are printed in PLA btw.

cwbullet said:

Did you post your files to thingverse?

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If this is directed to me no I have not since my 2.7x is simply Alex’s 2x blown up 135% in Simplify 3D.

Which I forgot to add is already on Thingiverse...

ABS can withstand heat a lot better than PLA which is why if you’re printing something that’s near the motor, do not use PLA. ABS will also not melt in a car unlike PLA

Update on the 2x Lander, I decided to reprint the whole model in ABS rather than PLA. Concerns about heat resistance and strength of PLA were the reason for doing so. The infill was adjusted on the legs and decent stage and honeycomb pattern was used so about a half of a pound was saved on the ABS reprint.




An altimeter was added for deployment although I’ll probably use the motor as back up.



Stickshock decals completed the model.
All up weight without motor is 3.96#.



First flight is planned on either a CTI H225 or Aerotech H242. Might realize 500’. Hopefully it will fly at the next WOOSH launch at Bong next weekend.

Looks great . I might have to make one myself .

alexzogh said:

View attachment 389652 Be careful with your motor choice. I was a little too aggressive on my first flight on the 2x. Mars Lander tried to revert to filament mid flight

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Missed this thread till now.

What the heck motor did you put into it?

Too many models shred not because they were too weak, but a motor with too much thrust was used in them.

Very nice

georgegassaway said:

Missed this thread till now.

What the heck motor did you put into it?

Too many models shred not because they were too weak, but a motor with too much thrust was used in them.

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George,

I believe Alex had a K454 in his. I actually witnessed the flight but didn’t realize it until later. Even have a poorly shot video....

K454?

Holy F....

No wonder. Don't blame 3D print for not holding up to that. Terrible over powered motor choice. Surprised it held together for as long as it did.

My 2x Lander flew successfully today at the Woosh launch at Bong. It went on a CTI H225 and boosted nice and straight. One leg broke on landing but I had the infill pretty low to keep the weight down. Maybe need to bump the infill up a bit when I print the new one. A bigger chute may help as well.

Here’s a video (I really need to get a better camera instead of using the phone...)

Some post flight notes: the H225 lifted the 2X Lander to ~740’. Had to wait until I downloaded the info to know for sure. I had my AIM altimeter mistakenly set to read out meters and wasn’t sure if the 2-2-6 beeping out was a mistake since the flight was clearly more than 226’.

Noticed some separation of the layers on the ascent stage after the flight.



I believe this is due to no support on the bottom of the descent stage and the whole airframe essentially hanging off of the center tube. I’ve added four strips of fiberglass and epoxy to strengthen the ascent stage as seen below.



Also I’m making a “thrust ring” to attach to the motor retainer to support the descent stage better. Trying not to add more weight but feel this is necessary. I will recheck total weight and CG once I’m done.

Sorry I missed the flight. Had to head back to work.

I assume you’ll wait for warmer weather next spring to try again?

Charles_McG said:

Sorry I missed the flight. Had to head back to work.

I assume you’ll wait for warmer weather next spring to try again?

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Work does take precedence. You’re lucky to have yours so close!
The Lander will fly again at another Bong launch I’m sure. Look forward to seeing another one of your two stage flights as well.

Widened the base for my thrust ring a bit and attached it to my retainer with an empty case to ensure proper seating. Had to compare Aerotech and CTI aft closures to be certain they didn’t vary much and they appeared to be the same. Guess I can always print a separate one if there’s a problem.

Pretty neat upscale.

georgegassaway said:

K454?

Holy F....

No wonder. Don't blame 3D print for not holding up to that. Terrible over powered motor choice. Surprised it held together for as long as it did.

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Heh...

I kind of cheated in my build. As I noted in the thingiverse details, I used traditional rocket materials for key structural parts of the rocket. Used carbon fiber for the base, fiberglass for the motor tube, wood for centering rings, and metal for motor retention. Launch and boost was great. The failure was I didn’t reinforce the shock chord mount, and set motor ejection a little early. Parachute ripped right out of the ascent stage and sailed away with the nosecone.. never did find it.



Working on a 4x now that will be 95% 3d printed.


John, your launch looked great. Sorry. I missed it.

alexzogh said:

Heh...

I kind of cheated in my build. As I noted in the thingiverse details, I used traditional rocket materials for key structural parts of the rocket. Used carbon fiber for the base, fiberglass for the motor tube, wood for centering rings, and metal for motor retention. Launch and boost was great. The failure was I didn’t reinforce the shock chord mount, and set motor ejection a little early. Parachute ripped right out of the ascent stage and sailed away with the nosecone.. never did find it.



Working on a 4x now that will be 95% 3d printed.


John, your launch looked great. Sorry. I missed it.

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Can’t wait to see it! Your builds are inspiring.