Project: 6" Ducted props (WIP)

[Kevin_Erik]

Duct for Tricopter V4

Assuming the image-hosting is working, you should see a slightly larger Duct for a 6″ propeller. I simply increased the outer-ducts diameter (152.4mm or 6″) and increased the duct height by 7mm. This was done to accommodate the Tricopter V4’s use of BE2217 motors and larger prop size. The support arms may need increasing in height but I’ll need to see the BE2217 first hand to get a better idea of how things will fit together. That is unless someone else can do this in direct comparison with the RS2205kv motor. Least this way i have a sense of scale.

Note: The filename says mini but I am sure this is the correct one for the Tricopter-v4. I just got lazy with the naming of files is all. Wish i could swap the files out here but i can’t

Cheers!

Kevin

Attachments:

1. 6-Inch-Duct-for-Tricopter-Mini-Version-1-Fusion-360-build.rar

[Kevin_Erik]

Blasted image-hosting isnt working…

Edit: Fixed the hosting issue by opening a Flickr account.

[LitterBug]

I run 6″ on my mini tri but am not using taller motors.

LB

[Kevin_Erik]

@LitterBug

I’ll make you what you need to ensure you have the best possible fit. However, unless you post something different, I’ll model the duct for use with the RS2205kv motor. (Size wise) This includes the bolt-holes, which can be a pain in the arse to drill out if you’re using anything harder than plastic.

BTW: Which ESC and Prop pitch are you using?

Oh before I forget, you absolutely want to use bull-nose props with the ducts. Otherwise you’ll not have the clearance required to negate the prop vortex’s. Clearances under 1mm are considered good, 0.5mm is awesome sauce.

Question: I can make the duct walls 1 mm thick instead of 2mm if you think that would help?

Cheers!

Kevin

[Kevin_Erik]

6″ Duct for Mini completed.

Note: Based off RS2205kv motor with 2mm wall thickness.

Cheers!

Kevin

Attachments:

1. 6-inch-Duct-for-Mini-Version-6-Fusion-360-build.rar

[LitterBug]

Normally I try to make things a multiple of .4mm, which is a pretty standard nozzle size. If you use 1mm for example, there will be a .2mm gap in the middle that the slicer/printer can’t fill.

I am using 30A escs, T-Motor F40 2300kv motors (believe they are 2204), and normally run 6×4.5×2 or 6×4.5×3 props. Have a wide variety of props, so props are not written in stone. I do have bull-nose props and am familiar with why to use them with ducts.

I printed another one of the 5″ ducts last night using single wall and it came out lighter. Enough that it could be felt holding them in my hands. It did not seem to suffer structurally. Had a co-worker do a blind weight comparison, and they could feel the difference too. Need to get my scale out for accurate weight.

Cheers!
LitterBug

[Kevin_Erik]

Ahh, i guess thats where the gap came from on the first printing i had done. Just how thick is a “single wall” print?

So now… Name your wall thinkness and I’ll post you a build with that. ( .4mm / .8mm / .12mm ect )

Question: what material(s) are you printing with? From what i understand, some of the plastic / carbon filaments are really good and can be used by most home printers.

Kevin

[Kevin_Erik]

Please post pics of the latest print. Curious how they came out as well as

how thick

the duct wall(s) came out.

Kevin

[Kevin_Erik]

Found a source online that gave detailed information on the physical dimensions required to achieve maximum lift.

Dt = Duct throat (diameter)
&tip = 0.1% Dt (blade distance from Duct wall)
Rlip = Radius of lip. (13% of Dt)
Ld = Length of the diffuser (50-75% of Dt)
Od = angle of diffuser (10° is ideal)

Also found a website that can create airfoils and profile them.
NACA Airfoil generator

Will draw a few sketches to see how close my current work is to the known “ideal” shape.

Cheers!

Kevin

[Kevin_Erik]

Made a quick duct-foil to get an idea of the shape(s) required.

Video Link, click here

Notice how the duct lip (16.5mm) is almost twice the current width!

Kevin

[Kevin_Erik]

Posted this reply to the correct thread (5″ Prop Ducts, Version-7 completed)

Kevin

[Kevin_Erik]

I’m having three prints of 5″ version 7 made from Carbon-PLA. Will try having 6″ Ducts made later in the month.

Kevin

[LitterBug]

I looked at the latest ducts and thought about printing them. There is a lot of overhang no matter which direction I would print it that would require a large amount of support material. Very time consuming as well as a waste of material. Estimated print time was 13 hours. =-O

LB

[Kevin_Erik]

Maybe better to have a third party print it for you then. Least that way you can choose a stronger / stiffer / liter material.

I am having three made for 30 euro + 4 for shipping. Will have them by Monday!

BTW, I have Version-4 printed and installed. Will post pictures later. Using HQ prop’s too… Bullnose 6x4x3 and the clearance is so tight! This will make a big difference with the overall efficiency.

Kevin

[LitterBug]

I may try to print it inverted and use manual supports. Much less to clean up that way. Inverted with automatic supports came out to 9 hour estimate. Will play with it this weekend.

LB

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