Project: 6" Ducted props (WIP)

[Kevin_Erik]

Here’s Version-4 installed

Notice how I shim the props, then tighten down the motor screws to ensure that the prop spacing is even.
The pieces of cardboard use as shims are exactly 0.5 mm thick (verified with micrometer). The cardboard does give a little so odds are the props are closer to 0.3 or 0.4 mm. If done correctly, the shims should not fall out while the motor mount is torqued down. (Use a cross pattern to tighten screws).

Note: Closer is better as this allows less air to sneak past.

I’m currently using HQ Prop’s 6x4x3 (Bull-nose) as this has more prop facing the duct wall and thus is easier to keep the air gap to a minimum.

Cheers!

Kevin

[Kevin_Erik]

@Litterbug

You printing out V7 5″ prop’s and out of ABS ?

Please keep in mind that the prop gap will be really tight. So sanding the inner wall smooth and centering the props is a must!

Kevin

[Kevin_Erik]

Made an improved 6″ version-7 for use with the Tricopter-mini.
Please notice the external support ribs and the strengthened joints. What you wont see is that the aero-lip is hollow to save weight.

Google Drive

[LitterBug]

Been off building some other crazy stuff for indoor season. Just now getting back to my tris. Looking to give these a go.

Cheers!
LitterBug

[LitterBug]

Well nuts…. not only is it the Winter Solstice with the shortest amount of daylight for the year, it seems to have been the Printer Solstice with the least amount of bed adhesion.

LOL
LB

Attachments:

1. 

   20171221_071120.jpg
   

[Kevin_Erik]

Which duct is that ?

[LitterBug]

The most recent 6″ V7 you posted in this thread. Or at least it was supposed to be. 😉

Hmmmm, Switching to F80 1900kv motors when they get here, so probably ought to hold off printing these anyway. Have you drafted new ducts for the F80 dimentions?

[Kevin_Erik]

I believe so but check the dimensions in 360 Fusion before printing just to be sure. I’d strongly advise you use Nylon if you have a dependable method of printing with it. (SLS- Nylon)

Nylon by far its the strongest, lightest and most flexable material out there for the cost / time involved. Yes, material flexability and rebound is good to have as it will save the ducts from cracking during hard impacts. Other materials do work but they are either too stiff, heavy, cost allot or have seperation / wrap issues during printing. It’s possible to print out a duct from ABS, fit-test it, smooth it, and then use it as a cast mold to make as many ducts as desired.

Keep in mind that i stopped the 6″ development after i received last ducts from the print house. The material (PLA) was already seperating as it didn’t seam to hold together at all during shipping. The one and only fit test attempted showed that all three ducts had massive amounts of warping despite all the support structures used. From what i understand, the print house made over a dozen copies until they has something stable enought to ship.

Hence, until i perfect the 5″ ducts I wont be trying out another 6″ duct knowing what the outcome will likely be. I can however make alterations to suit your specific needs of you can forward me specifics on what’s needed.

Kevin

[Kevin_Erik]

One option I’ve been seriously considering is the development of the various duct sections as stand alone parts. Motor-Hub “Hub”, Struts, Stabilization-Ring “Stab-ring” and Duct-Wall “Wall” ect. Just for an example: A completed Duct would require (1) Hub, (3) Struts, (1) Stab-Ring and (3) Walls.

Note: The Wall would be cut into 3rd’s, thus requiring they’d be jointed together via the Stab-Ring. Think of the Stab-Ring acting as a collar around the outside of the Wall, where screws are inserted through. These screws are pushed thru into the Struts and Hub, binding everything together.

This would allow the following:
* Standardization of parts thus allowing for the repair or customization of a Duct rather then its total replacement.

* Parts that can be reoriented to allow for inverted Ducts without having to redesign the whole thing. (Flip the Hub over and slide whole assembly towards the top of the Duct rather than it’s bottom)

* Printing would be easier & more reliable as warping / separation would be less likely printing smaller parts.

* Different sized Hubs can be created to allow multiple motor sizes to be compatable with any Duct. The same could be true of the various other parts once a standard has be established.

As always… Your thoughts and comments are welcome.

Kevin

[LitterBug]

I’d like to do nylon, but the printer big enough to do the ducts with is currently only able to reliably do PLA and ABS. Will be ditching the stock firmware on it soon which currently restricts material choices. Will be switching to Repetier firmware and it should be interesting to see if that fixes some of the other issues I’ve been having, or if the extruder and hot end will need to be upgraded as well. I’m in the flip flop stage of deciding whether it’s worth the effort to upgrade the firmware, hotend, and extruder, or just get a completely different printer. Leaning to upgrading the current one since it should be plausible to do for much cheaper.

If those parts warped and separated in shipping, they must not have been packed well, or were not printed well to begin with.

I’d lean to keeping it a one piece design. I’ve been playing with a 3D printed ducted octocopter with the initial thought of seperate ducts and frame. In the end, it ended up a two piece and I really should have just done it as a single piece AIO frame.

LB

[Kevin_Erik]

Nice Octo!

Due to the size of the props it makes sense to have it AIO.
Guessing thats 3″ ?

You can try to do the AIO print but i think it will be a real pain in the arse for the 6″ props. Like i mentioned earlier, the printhouse i went through had one hell of a time with just ABS. Originally i contracted them for a Nylon print but as you can imagine, the Nylon looked like a bag of ass, which why it was abandoned. Aparently, the only reliable way to print large complex Nylon structures is SLS. My tri’s bodykit was done that way and came out much better than any of the other work I’ve had printed thus far.

Note: I could design anyhing you want, just ask?

Cheers!

Kevin

[Kevin_Erik]

*** Don’t use the duct with winglets! ***

They dont work and ended up being the first thing to break on the 6″ print job.

Kevin

[Kevin_Erik]

The duct shown on this thread from the October 9th post should be fine as it doesn’t have winglets. However it maybe sized for the 2205 motor… been to long sinse I’ve messed with this to be sure so please double check before printing it.

[LitterBug]

Octo is 1.9″ props and roughly 8″ diameter.

Ok. so I tried the F80s that came today on some of the 5″ ducts I printed near the beginning of your testing… Do not fit. Here’s the specs:

Cheers!
LB

[MadPoet]

Hi Kevin,

I downloaded your STLs but unfortunately they are too big for my printer, with a print capacity
of (W) 140 x (D) 140 x (H) 135mm. So I will not be able to test these on my Baby Tri. Should you update the top lips on the model to bring it into a size I can work with, let me know.

Cheers,
~Eric

[Author]

Posts