34 replies to this topic

[Brian]

SeismicCWave, on 19 February 2012 - 06:09 PM, said:

Yup, these are the arms I am going to try next:

http://www.wheelspin....co.uk/i/90685/

How do you mount those tubes to the frame/motor?

[DanZ]

Brian, on 19 February 2012 - 06:13 PM, said:

How do you mount those tubes to the frame/motor?

You will need to cnc a clamp suited for that shape.

Those tubes are very interesting and if strong enough should work very well. I searched for ages for similar shaped tubes, the closet I could find were aluminium wing strut bracing, but it was far too heavy.

[Brian]

DanZ, on 19 February 2012 - 06:24 PM, said:

You will need to cnc a clamp suited for that shape.

It would be nice to find pre-made clamps.  Those tubes combine the benefits of both the square and round tubes.  The motor can't rotate around the arm, and it's even more aerodynamic than round arms.  The only problem I can see (aside from the cost) is that it looks like it's protruded CF, and likely has to be protruded.

[Arnie]

an alternative would be using conventional square tubing with molded foam or plastic fairings mounted above and below the arm's. Simple, cheap, and light.

[SeismicCWave]

Brian, on 19 February 2012 - 06:13 PM, said:

How do you mount those tubes to the frame/motor?

I am putting the tubes through some plywood bulkheads. Then I box the bulkheads with vertical walls on the side and some top and bottom plates. I am using some Loctite Hysol epoxy and that should hold everything in place nicely.

I am attaching a jpeg version of my plywood quad. You can see the bulkhead on the right side of the drawing.

It will be very light and strong. The tubes are just like the normal pultrude carbon tubes. The cross sectional dimensions are 12.5 mm wide and 19 mm tall. So that is very strong for a good mid size machine. I plan to use Avroto 2814/11 770 kV motors with those arms and I can haul up a Panasonic GH2 without problem. I can probably haul up a Canon T2i but that will be pushing the limit.

Attached Files

•  Koa quad.jpg   76K   32 downloads

[LemaLife]

follow up question to this thread which applies to all Y6 configs too.  on the inverted motors, the props have to still be "right side up" so that they push downwards.  This makes it a bit difficult to use a shaft adapter with the props no?  In my Y6, I found that the hole in the prop near the base of the motor (which is inverted) is a little loose (because the base of the shaft is slightly thicker than the threaded part).  

how are people dealing with that or does this even make sense what I'm saying?

[Windbreaker]

SeismicCWave, on 19 February 2012 - 10:36 PM, said:

I am putting the tubes through some plywood bulkheads. Then I box the bulkheads with vertical walls on the side and some top and bottom plates. I am using some Loctite Hysol epoxy and that should hold everything in place nicely.

I am attaching a jpeg version of my plywood quad. You can see the bulkhead on the right side of the drawing.

You might try what I did to make round tubes square: Make a mold out of Plexiglass that fits closely around the tubes. Give the mold several coats of carnauba wax (Maguires has a wax formulated for this kind of work), then seat the tubes in the mold with a thick (and lightweight) mix of epoxy and Q-Cel or microballoons. When it cures, it'll pop right out of the mold with a nice rectangular cross-section that's easy to fit into your frame. Might have to make a jig to make sure the teardrop-shaped cross section is held perfectly aligned with the rectangular cross-section.

This way the arms aren't bonded permanently in place and can be easily replaced or repaired.

[SeismicCWave]

LemaLife, on 20 February 2012 - 06:41 PM, said:

follow up question to this thread which applies to all Y6 configs too.  on the inverted motors, the props have to still be "right side up" so that they push downwards.  This makes it a bit difficult to use a shaft adapter with the props no?  In my Y6, I found that the hole in the prop near the base of the motor (which is inverted) is a little loose (because the base of the shaft is slightly thicker than the threaded part).  

how are people dealing with that or does this even make sense what I'm saying?

Most APC props have a 6 mm adapter that is undersize. I have to ream it out for the smooth part of the prop adapter. For the inverted mount propeller just don't ream it out and it should fit fine on the threaded portion of the prop adapter.

[SeismicCWave]

Windbreaker, on 20 February 2012 - 10:07 PM, said:

You might try what I did to make round tubes square: Make a mold out of Plexiglass that fits closely around the tubes. Give the mold several coats of carnauba wax (Maguires has a wax formulated for this kind of work), then seat the tubes in the mold with a thick (and lightweight) mix of epoxy and Q-Cel or microballoons. When it cures, it'll pop right out of the mold with a nice rectangular cross-section that's easy to fit into your frame. Might have to make a jig to make sure the teardrop-shaped cross section is held perfectly aligned with the rectangular cross-section.

This way the arms aren't bonded permanently in place and can be easily replaced or repaired.

LOL yes that is the proper way to do it. I am just lazy. Besides when I crash a machine the arm is the least of my worries. I usually crash it from such a great height I have nothing to salvage. So I usually don't make my arms removable. That would make a lot of sense for me for traveling though.

[AlPackin]

hmmm, I just got the motors for my BlueSky micro hexa build.  I've been pondering how I wanted to build that frame.  I'm going to build it upside down those wide flat arms deserve it

[SeismicCWave]

AlPackin, on 20 February 2012 - 10:36 PM, said:

hmmm, I just got the motors for my BlueSky micro hexa build.  I've been pondering how I wanted to build that frame.  I'm going to build it upside down those wide flat arms deserve it

The problem with the BluSky RC frame is that the landing gears are on the motor mounts. The micro hexa is different. It doesn't have a landing gear. You will need to use a landing gear to mount the motors upside down.

[AlPackin]

I remembered that I had a weirdo micro quad with motors mounted under the arms.  I did a flip of the whole thing so the motors are on top and the props underneath, it flies pretty well so far ... does need better landing gear though

[SeismicCWave]

AlPackin, on 22 February 2012 - 01:31 AM, said:

I remembered that I had a weirdo micro quad with motors mounted under the arms.  I did a flip of the whole thing so the motors are on top and the props underneath, it flies pretty well so far ... does need better landing gear though

Yes it does fly very well even without landing gear. I guess  the battery lifted the machine high enough to clear the props.

[AlPackin]

SeismicCWave, on 22 February 2012 - 04:47 AM, said:

Yes it does fly very well even without landing gear. I guess  the battery lifted the machine high enough to clear the props.

It does have landing gear but it's hard to see in the low light video.  It just has four, 2" long 6/32 nylon screws with nylon sleeves on them.  It helps for the takeoff, pretty hard to land on though.  Kind of spindly legs

[elmuchacho]

I've done it on my fpv quad



- I thought it will look cool and it does give you a really different feel when you fly mostly you are going to kill everyone much faster then with a normal quad.
- The sound is awesome when you compare the 2
- I've adapted a higher landing gear because without it I still break too much prop on fpv landing none on normal landing without fpv
- I found harder to completely remove drifting then with conventional quad.

Anyway the real reason to build it that way is to adapt one of this frame around the prop
http://www.kkmultico...ll_230&id_no=64

- The goal was to get the quad flying before the protective frame do all the tunning and then add the frame without having to unbuilt the machine

cons: I break much more prop on that config