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Pumpkin drop event

Good 300ish Frames with Carbon Tube arms?

Robbie

Senior Member
#1
Hey guys,

I am in the market for a new 300 frame and the mxp300 is a possible option, but i really want carbon tube arms for the extra efficiency, strength and it makes turning the motors 10 degrees easier. I have thought about retrofitting either of the Mamba frames but i was wondering if anyone knew any obscure frames which either have carbon tube arms or one that i could at least retro fit to have carbon tube arms.

Thanks
 
#3
Yeah I would keep an eye on the Carbon Fibre tankito, the G10 one just seems too heavy and quite weak.

You could consider the Blackout 330, but you won't be able to angle the booms.

One option is a scratchbuild, you could 3d print some clamps for the arms (or even steal some off the Cinetank or Mamba) and then you could customise to central section to your liking.
 

HawkMan

Senior Member
#4
Extra efficiency ? Tubes aren't really more efficient than flat/square arms though :/

The Komodo is a awesome looking quad though. unfortunately a lot of the tube arm quads, especially of the 300+ size have angled tube arms, making turning the motors 10 degrees less efficient.
 

Robbie

Senior Member
#5
This is about the only thing I can find that is similar to what you are asking for:

http://sec3research.com/site/cart2/index.php?main_page=product_info&cPath=2&products_id=85

However the new Flying Cinema Tankito30 is correct size wise and the arms can be mounted at 0* and 10*

http://flyingcinema.com/tankito30.html

It just doesn't meat your tubular arm concern.
yeh the carbon tankito30 is an option, thanks for the komodo looks seriously good and a possible option, there something about the circular arms they feel stronger and having the flown some with tube arms i like their flight characteristics.
 
#6
Extra efficiency ? Tubes aren't really more efficient than flat/square arms though :/

The Komodo is a awesome looking quad though. unfortunately a lot of the tube arm quads, especially of the 300+ size have angled tube arms, making turning the motors 10 degrees less efficient.
CyberDactyl's CyberHex has a good explanation of the inefficiencies of most mini-qauds when it comes to Thrust Column Efficiency. Cyber can probably explain further but I believe that carbon fibre circular booms are good at reducing loss, not only in hovering, but also in foward flight over simple flat horizontal booms.
 
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jipp

Senior Member
#7
iv seen a few ESC that are being stretched so they can go inside carbon tubes. hey maybe it was CineTank that was selling them.. i thought it was a cool idea to clean up ones MR.

chris.
 

jipp

Senior Member
#8
CyberDactyl's CyberHex has a good explanation of the inefficiencies of most mini-qauds when it comes to Thrust Column Efficiency. Cyber can probably explain further but I believe that carbon fibre booms are good at reducing loss, not only in hovering, but also in foward flight over simple flat horizontal booms.
thanks for the link to the cyberhex.. that is one cool design..
so many cool frames id love to play with.

chris.
 

HawkMan

Senior Member
#11
CyberDactyl's CyberHex has a good explanation of the inefficiencies of most mini-qauds when it comes to Thrust Column Efficiency. Cyber can probably explain further but I believe that carbon fibre circular booms are good at reducing loss, not only in hovering, but also in foward flight over simple flat horizontal booms.
circular booms case a vortex under the boom causing drag and reducing efficiency nearly as much as a well designed flat boom. for a round boom to be efficient, it needs a drop shape giving it more of a downward wing form which eliminates or reduces the vortexes and drag .
 
#12
circular booms case a vortex under the boom causing drag and reducing efficiency nearly as much as a well designed flat boom. for a round boom to be efficient, it needs a drop shape giving it more of a downward wing form which eliminates or reduces the vortexes and drag .
Ah okay didn't realise this, I'm not an aeronautical engineer so hardly know anything.
 

Cyberdactyl

Misfit Multirotor Monkey
#13
Take a 20mm dia. round boom, they are ~4X more efficient than a flat plate of the same planform area. A thin vertical plate of about 15% the planform area of the flat plate is ~6X more efficient. A vertical airfoil boom of about one third the planform area of the flat plate is >8X more efficient. . . . all this assumes mini-MR thrust column speeds.

Now, please don't misunderstand, that is NOT saying a round boom gets 4X more lift or flight time as a flat plate of the same planform area. It is simply a relative thrust column efficiency that should be considered among all the other variables that make up a well designed MR.

We're talking a flight time variation of a maybe just over a minute at the most extreme from worst to most efficient, unless the MR is over-the-top grossly inefficient, such as the prop disc being blocked by a large area of the MR's frame, as has been done many times. Many designers certainly must be aware of the efficiency variation, but see no need to go to any considerable effort to buy that moderate amount of additional flight time or additional two or three dozen grams of lift, at the most, especially if it interferes with crash strength, ease of construction, cost, etc.

Here's an excellent demonstration of planform efficiency at a thrust velocity of ~290ft/sec. It's a really old video that explains it clearly as any you will find. But within the video, THIS comparison of thin wire to a rather 'fat' airfoil of 10X the wire width is most striking.
 
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Robbie

Senior Member
#14
Here's an excellent demonstration of planform efficiency at a thrust velocity of ~290ft/sec. It's a really old video that explains it clearly as any you will find. But within the video, THIS comparison of thin wire to a rather 'fat' airfoil of 10X the wire width is most striking.
I love these old 50s education videos, 10x better than anything down nowadays

And i understand your point, i am desperate for tubular arms, but no frame makes use them :(