Pete's diy Big Hex Mk2 build blog

Stacky

Member
Is there any info on what impact longer arms have on flight characteristics? With my mockup with t580 props on (12inch) I have a little bit of wiggle room to shorten the arms and keep the props out of view.
 

Efliernz

Pete
The biggest I've seen on the forums is 900mm. I am only going big as I regularly fly high and visibility becomes an issue with little models.


Progress on Hex Mk2.
90 minutes in the shed tonight using the last of my 2mm carbon plate and my new 12mm square aluminium. Colour is from self-adhesive model aircraft trim from my past dark history of plank building and flying.
 

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Stacky

Member
Yeah, its one of those things where I am trying to work out how long the arms should be based on camera angle views and props coming in to view which doesnt seem to be a very scientific approach.
 

rockynz

Member
I was reading somewhere that its good if the spaces between the props are the same size as the prop itself. I had a quick guesstimate with 10" props and found motor to motor would be almost 1000mm for a hexa.

Any thoughts on the subject?
 


Efliernz

Pete
Yeah, its one of those things where I am trying to work out how long the arms should be based on camera angle views and props coming in to view which doesnt seem to be a very scientific approach.

A good time to have your camera way below the main chassis. I am also going to have my camera slightly forward, balanced by the batteries at the rear of the centre hub. By having the camera forward, I increase the angle/gap between the base of the front arm and the top of the fov.... I hope.

And then is the drag issue of having too much hanging underneath. I was flying the tri is 20+ mph today and my fwd speed sucked! If I had an under-slung mount on my tri, I would have been in trouble.
 



Efliernz

Pete
I don't mind ;)
It's a change from camping in your corner.

Guys - I presume the new boards with accelerometers and gyros and gpq and magnet compasses won't like my magnetic folding arm system?



So - how many flew over 90 minutes air time this weekend without crashing? I even pushed it with 6 loops :)
 
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matwelli

Member
@rockynz - nope its by our club president brendon, its from two aluminium arrow shafts, i quickly snaped those pics today, because i thought you would be interested, same frame as yours

@efliernz - a magnetometer will be affected by the magnets, power wiring also affects the magnetometer - coptercontrol dosent have a magnetometer however
 

Efliernz

Pete
@efliernz - a magnetometer will be affected by the magnets, power wiring also affects the magnetometer - coptercontrol dosent have a magnetometer however

but the new Minsoo Kim board has magnetic sensors...

I have the arms attached with wingnut bolts. Motors are now mounted but I don't feel like soldering a million wired tonight. I have esc's all mounted on a panel like pieces of cooling toast on the top rear of the central hub. I might need to move the esc's out onto the arms if interference becomes apparent with later controllers.

The battery and camera mount get designed next - but they will be adjustable fwd and backward. I have already designed and built these for my big helis before so not too stressful.

Pete
 

matwelli

Member
ahh...yes :)

i have heard you can use a copper shield between the magnetometer and the electromagnetic stuff, not sure on the fixed magnets tho
 

Efliernz

Pete
I'll stick to the wingnut system at this stage. The progress so far is good. Very sturdy. I have a long way to go before I need to start thinking about compass sensors. I'll get this built this week I hope. I am waiting for HK to send what I paid for a week ago... 'cause there are some "special" items in the order for the hex... :)
 


rockynz

Member
@Mat... yep I like the frame a lot! very professional. Any idea where he sourced the nylon parts?

@Pete... I very envious of how far you've got with you build. Can't wait to get to work tomorrow and get on with my project. Main job is to source arm tubes, not sure if round, square or rectangular yet but they will be ali! The span is probably going to start at 1000mm because I can always make it smaller :) Aiming for 10"prop 10"gap 10"prop spacing. I'll ask my boss to plot it on his cad so I get it right but don't think it will be much less than a meter.
My frame will fold the same way as yours but from a very small center plate. I will have a removable landing gear, camera mount battery holder that will locate each arm when attached.
With a bit of luck I'll have 6 motors delivered tomorrow too :) No idea how long it will take rctimer ESC's to get here though. Apart from that I only need my FC and thats on its way too1
 

Efliernz

Pete
@Rocky... if you need 6 rctimer esc's in a hurry, I have them spare. PM me or email me (my forum name @gmail.com)

Hunting for tube became a mission last Friday. I have 10 and 12mm round tube (which looks great when used) but the square is just so easy to use. No extra brackets or alignment issues. I found my local Ulrich-Aluminium (also happens to be a large distributuon centre) has a retail store. $18 for 5m of 12x1.6 wall square. They even chopped it in half for me :)
The 10mm round will become the top front-to-back runners like in Mats photos.

@Mat... double quad??? That is already sort of what you do with a V isn't it... except yours looks like its crashed before takeoff!!! Sorry... the V models do look cool.
 
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Efliernz

Pete
Looking good. You just need a park now!

I broke my tri tonight. I needed 3' for elevation before the loop. One broken 12mm pine arm...
 

rockynz

Member
hey Pete,

have to pass on the ESC's but thanks for the offer. Just have to wait for the ones I've paid for :-( Cash for this project nil at moment.
I spent all day looking for tube and ali sheet. Found some cool tube 20x14x1 it has an internal fixing cannel down one side but hey I think I can work with it as it cost me zero bucks :) May do a bit of fancy milling to loose some weight while I wait for parts to arrive.
I still need to find some sheet off cuts in 2 or 3mm
I'll have to start my own build blog soon and stop hijacking yours Lol

@Mat...gotta whole lotta love for that V8 man!
 

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