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RCExplorer David's tricopter v2.5 scaled to inches

#1
David's plans are great, but all the local hardware stores for me don't carry 10mm basswood booms...

So I took his plans, converted them to inches and scaled them up to use 1/2" - here's the measurement changes:

(The conversion factor ends up at 1.27, or 1/2 inch per 1 cm)

  • 3mm drill holes change to 7/64" drill bit, to use #4-40 screws
  • 10mm = 0.5" (distance between holes for rear boom, stick size, etc)
  • 20mm = 1" (Axel-hole distance for front arms)
  • 50cm Boom length = 25"
  • The "dampened gopro mount" stick will measure 9.5" x 2"

I also scaled the template itself so that I could print it and paste it directly to my G10 boards. One plate is just slightly longer than a 6"x6" G10 board from McMaster-Carr (cat# 85345K712), so a pair of boards can cost you less than $7 + shipping.

I'll release the PDF I made for printing once I get permission from David, but here's a photo of my progress so far: (*edit: got permission. Here's the PDF file for printing*)

tricopter-in-inches.jpg
 
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#3
I wanted to use 1/2" square wood booms for the arms, instead of 10mm booms. David's plans are measured out for 10mm sticks, which the local hardware stores typically don't carry. They do have 1/2" sticks though, so in order to make everything measure out properly the easiest way is to simply scale the whole copter up slightly.

This way I can buy all my parts and pieces for the frame locally instead of having to order nuts, screws, and wood from Hong Kong.
 

bicyclemonkey

Flying Derp
Mentor
#5
I wanted to use 1/2" square wood booms for the arms, instead of 10mm booms. David's plans are measured out for 10mm sticks, which the local hardware stores typically don't carry. They do have 1/2" sticks though, so in order to make everything measure out properly the easiest way is to simply scale the whole copter up slightly.

This way I can buy all my parts and pieces for the frame locally instead of having to order nuts, screws, and wood from Hong Kong.
You can order the 10x10mm x 36" wood for arms from this place in FL for $1.30 each

https://www.magnumwood.com/cart/Product.aspx?ProductId=942
 

ananas1301

Crazy flyer/crasher :D
#6
I can buy all my parts and pieces for the frame locally instead of having to order nuts, screws, and wood from Hong Kong.
That is an advantage for sure! I did that as well. Only srews and nuts had to be ordered, but I have enough of them for a second frame and you don´t really loose them often, do you.

Nice build and good luck for the rest of it.
 
#7

Burg

Never catch a multirotor
#8
The important part is that anyone else who wants to use 1/2" booms can print the template directly, and transfer it onto their boards without having to scale it themselves.
Very nice !

Our local hard ware store supplies only 8x8mm and 12x12mm wooden sticks.
The 10x10mm are supplied by the RC-shops, and more expensive.

Your 1/2" x 1/2" is exactly 12.7 x 12.7 mm !!
So with your re-scaled plans I can use the 12x12mm sticks.
Bundle of 6 pcs (6x 210cm / 82") for USD10,30.
I can make 8 tricopters with that ;-)
 
#9
David's plans are great, but all the local hardware stores for me don't carry 10mm basswood booms...

So I took his plans, converted them to inches and scaled them up to use 1/2" - here's the measurement changes:

(The conversion factor ends up at 1.27, or 1/2 inch per 1 cm)

  • 3mm drill holes change to 7/64" drill bit, to use #4-40 screws
  • 10mm = 0.5" (distance between holes for rear boom, stick size, etc)
  • 20mm = 1" (Axel-hole distance for front arms)
  • 50cm Boom length = 25"
  • The "dampened gopro mount" stick will measure 9.5" x 2"

I also scaled the template itself so that I could print it and paste it directly to my G10 boards. One plate is just slightly longer than a 6"x6" G10 board from McMaster-Carr (cat# 85345K712), so a pair of boards can cost you less than $7 + shipping.

I'll release the PDF I made for printing once I get permission from David, but here's a photo of my progress so far: (*edit: got permission. Here's the PDF file for printing*)

View attachment 2290
in the pdf link, the front arm holes are .75 but above you mention 1" axel hole distance for front arms.

would you please verify which is correct?

Thank you

TTS
 

colorex

Rotor Riot!
Mentor
#10
in the pdf link, the front arm holes are .75 but above you mention 1" axel hole distance for front arms.

would you please verify which is correct?

Thank you

TTS
On David Windeståls template he states 20 mm which is roughly 0.75" . It doesn't really matter - you could have up to almost 1.25" without any problems, but it's not needed.

If things don't fit, remember the pivot screws are the ones on the inside, not the outer ones.
 
#11
ok thanks.

so no matter where i put pivot hole, when i have all three booms attached, motor shaft to center of gravity should all be equal, correct?

thanks for the info. im a newbie. this my second tri, first homebuilt. my first tri is a blueskyrc tri. i am building this one so that i can have a folding tri to travel with.

TTS
 

Bolvon72

Senior Member
Mentor
#14
Just for the sake of information; if you want to use the plates FT sells instead of scaling and cutting your own, you can use 3/8 inch sticks which are easy to find in most US stores. Lowes has them in poplar which works fine. They are 36 inches which I cut in half, 18 inches equals 45.7cm which is just a negligible amount shorter than the 48cm David calls for.
 
#15
Just for the sake of information; if you want to use the plates FT sells instead of scaling and cutting your own, you can use 3/8 inch sticks which are easy to find in most US stores. Lowes has them in poplar which works fine. They are 36 inches which I cut in half, 18 inches equals 45.7cm which is just a negligible amount shorter than the 48cm David calls for.
Yes, this is an excellent point. My local hardware store didn't have 3/8" which is why I scaled it up. The 10mm plans work great for 3/8" (9.525mm) booms.