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3D Printed 250 Racer Build Log

#21
Update 6:
Just need to set up the VTX and she'll be done but I will be tuning and getting first flights in without FPV first anyways.
IMG_20150314_140738.jpg IMG_20150314_140833.jpg
 
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#24
Awesome!

That thing looks great in the air, especially the yellow. I see you added some side supports in the middle of the frame. Do you have closeup pictures of the new parts?

:cool:
 

jipp

Senior Member
#26
it sure looks durable.. i went to town yesterday and picked up some plywood for my tri-copter project for a future project, unfortunately they did not have what i wanted.. but they did have a sale on some glow in the dark bright Neon color paint, i picked up l10 containers of the paint.. from yellows, to oranges, to pinks, etc.. i figure it will work perfect to paint the wood frame with. and if i can get black LED lights, it will be even brighter during the day. best part i scored all this paint for a whole 3.79. plus tax. evil tax. heh. anyhow, i figure for that price it would be worth it for visibility on the 3d printer tri-copter to plywood door stop project. :D worse case ill have to find another use for this glow in the dark neon paint stuff.
chris.
 
#27
That thing looks great in the air, especially the yellow. I see you added some side supports in the middle of the frame. Do you have closeup pictures of the new parts?
The side brace is the only new part at the moment and will probably be the last piece unless there is a durability problem somewhere on the quad.
Capture.PNG

You did an amazing job, what kind of printer do you have?
Thanks! I use a Ultimaker 2. Due to the size of the upper and lower chassis plates, an 8x8" build surface is the minimum for this build and you would need to print both PLA and ABS. I designed the chassis plates so that they could be laser cut though which means a PrintrBot Metal with heated build plate or something similar could build this frame if you have the chassis laser cut. I would really like to build one of these with a carbon fiber laser cut chassis at some point when the design is finished but I can't find a place that could do that for me at a reasonable price.
 
#28
Update 8:
Flew FPV today and it went great. I did find a weak point in the frame which is the pivot locks. They haven't broken but they are showing stress from all the pivoting and crashing. I can recondition them with heat but eventually they will have to be replaced. I'm going to attempt at bulking that part up a bit but I don't really thin that will help all that much. I've also determined Gemfan 6x3 props are the least durable props I've ever flown with. I've only crashed this quad twice and both time all 4 props broke, some of them broke both sides. I even tried boiling them to soften up the plastic but that was no help. I'll be switching to 6x3 and 6x4.5 HQ props from now on.
 
#29
Update 8:
Flew FPV today and it went great. I did find a weak point in the frame which is the pivot locks. They haven't broken but they are showing stress from all the pivoting and crashing. I can recondition them with heat but eventually they will have to be replaced. I'm going to attempt at bulking that part up a bit but I don't really thin that will help all that much. I've also determined Gemfan 6x3 props are the least durable props I've ever flown with. I've only crashed this quad twice and both time all 4 props broke, some of them broke both sides. I even tried boiling them to soften up the plastic but that was no help. I'll be switching to 6x3 and 6x4.5 HQ props from now on.
Have you considered doing some acetone vapor smoothing on the ABS pivot locks? That may provide a stonger more durable part.

PLA will fatigue too. I've haven't flown my tricopter yet, but I have actuated the arms quite a bit and I can already see signs of where the PLA is starting to fatigue. I'm guessing on yours, yours is showing similar fatigue, especially since you have all corners of the snap bolted in:

PRINTED QUAD.jpg

Once I get mine up and flying I am going to work on re-designing the locks slightly. I am going to try to improve how the bending load is distributed in order to reduce the stress concentration. I don't have access to simulation software though, so I am just going to take a couple stabs in the dark and hope it works.
 
#30
Have you considered doing some acetone vapor smoothing on the ABS pivot locks? That may provide a stonger more durable part.

PLA will fatigue too. I've haven't flown my tricopter yet, but I have actuated the arms quite a bit and I can already see signs of where the PLA is starting to fatigue. I'm guessing on yours, yours is showing similar fatigue, especially since you have all corners of the snap bolted in:

Once I get mine up and flying I am going to work on re-designing the locks slightly. I am going to try to improve how the bending load is distributed in order to reduce the stress concentration. I don't have access to simulation software though, so I am just going to take a couple stabs in the dark and hope it works.
The direction of the fatigue is perpendicular to the layers so I don't think acetone smoothing would help too much but it's worth a shot.

I originally printed them in PLA and they snapped in half the first time I attempted to snap the carbon tube in haha.

short of beefing up the area around fatigue, I'm not sure there's much we can do because the part has to flex in order for the mechanism to work.
 

cranialrectosis

Well-Known Member
Mentor
#31
Update 8:
Flew FPV today and it went great. I did find a weak point in the frame which is the pivot locks. They haven't broken but they are showing stress from all the pivoting and crashing. I can recondition them with heat but eventually they will have to be replaced. I'm going to attempt at bulking that part up a bit but I don't really thin that will help all that much. I've also determined Gemfan 6x3 props are the least durable props I've ever flown with. I've only crashed this quad twice and both time all 4 props broke, some of them broke both sides. I even tried boiling them to soften up the plastic but that was no help. I'll be switching to 6x3 and 6x4.5 HQ props from now on.
HQ props are the SHIZNIT. I love them and fly them on all my minis!

However, they will break FAR sooner than a Gemfan.

Sorry, Gemfans are horrid little props because they bend. But in a crash, they bend. HQs NEVER bend.

Stick with the Gemfans until you get to the point where you don't crash nearly as often or to the point where you just don't care about the cost of props because you have a flight addiction. :)
 
#32
Which size Gemfans are you using? I have a ton of their 5x4 and they're durable enough but for some reason these 6x3 where crazy brittle. Neither of my crashes with the Gemfans have been that rough and yet like clock work all 4 would shatter. I think glass props would have been tougher.
 

cranialrectosis

Well-Known Member
Mentor
#33
I was running 5030s and 5040s with two and 3 blades.

I also run nylon 8045s which last longer than the glass 1045s I run on my Anycopter.

HQ makes great props, but they are brittle. I still think you will like them. Just not so much for durability. :)
 

HawkMan

Senior Member
#34
The direction of the fatigue is perpendicular to the layers so I don't think acetone smoothing would help too much but it's worth a shot.

I originally printed them in PLA and they snapped in half the first time I attempted to snap the carbon tube in haha.

short of beefing up the area around fatigue, I'm not sure there's much we can do because the part has to flex in order for the mechanism to work.
How about Pet+ ?

http://madesolid.com/pet+.html
 
#35
PET+, PETG and ABS all have very similar elastic qualities so I doubt the results would differ very much between the three when it comes to fatigue. I might try a nylon or Taulman's PCTPE, but ultimately I want to make this design out of PLA and ABS because those are the most common 3d printing materials which will make it easier for others to make there own if they want.
 

jipp

Senior Member
#37
ben heck from the nerd youtube show "the ben heck show" , has a video on 3d printing tips. he shows how to make some parts stronger by adding a round over. could this method, or the super glue method make the part stronger?

here is the video to the 3d printer info. i love nerd stuff, so i like some of the projects he does even if his advertising for element 14th gets old. LOL.

he even built a quad last year think its 3 episodes.

here is one of three videos he has on 3d printer tips, and tricks etc..
at 11:30 or so he shows how he made a part stronger by rolling the edge, etc. from my back ground in wood working i understand why this would be better than a squared edge for durability/strength.. so i guess you can look at 3d printer sorta like working with wood.. or at least thats how i would look at it since thats what i have the most experience with. and its always easier to learn something new when you can associate it with something you already know.. doh.
chris.
 
#38
PET+ is supposed to be a lot ore durable than ABS though. more able to flex as well which should help with this particular application.
That seems to be mostly marketing from my experience. PET+ is easier to print but the increase in durability and flexibility are marginal considering the problem I'm facing. My problem is a point force fatigue which is better solved with better design than a new material.

ben heck from the nerd youtube show "the ben heck show" , has a video on 3d printing tips. he shows how to make some parts stronger by adding a round over. could this method, or the super glue method make the part stronger?
.
Superglue would most likely make the part more brittle instead of flexible so it probably wouldn't help. Using curves is indeed stronger and may be a decent solution to this problem if done correctly.

Ultimately the best is probably a combination or reinforcing the design and reducing the fatigue stress. I'll play around with it this week and see if I can get it dialed in.