1st FPV quad build

[XH558]

Well now the helmet';s done I';ve started on the quad itself.

After lot';s of research and ideas from here I decided against a TBS Discovery clone preferring the look of the QAV 500 ... so I got together my 3mm ply and aluminium arms and ordered some crucial little gizmos they actually use on the original - the little orange flexible bobbins... brilliant idea they are ....

I did some measuring of pictures and having had no luck on here asking for QAV original measurements I pretty much made it up after that 

I decided on 15mm x 30mm x 2mm aluminium arms as that is conducive to 15mm standoffs on the ';dirty'; plates ... I have used 4 x Opto 30 escs off my Hex and a power distribution board from HK hacked about a bit with the escs soldered directly to it..... I shall take the motor wires down the aluminium arms and plug directly into the escs.

I have experimented a bit with motor mounting but haven';t yet decided how I';ll do it.

So here it is so far .. it';s not elegant ... but it';s functional .. and more importantly I made it all myself    It looks a bit like Swiss cheese but I finally decided that drilling some lightening holes was preferable to drilling one hole threading the scroll saw blade through - cutting a hole - & then threading the blade back... over and over again ...was a pain in th';arse ... so easy drilled holes it is  There may be more yet ... it';s early days ... there';ll be some in the arms too.

It';s only loosely connected at the moment just to see how it looks - I think it';ll be fine ... it';s probably a tad heavier than a real QAV - but what the hell 

[Gav]

Nice work looks great! .  Good to see a DIY frame in the making.
Gav

[Biffa]

That';s looking really cool.

Are you going to keep it ';au naturel'; or will it be getting a coat of paint?

[dp106]

That looks really cool, a lot more professional than my home build attempts :-) How do you work out the length/angle of the arms? I built a h-quad based on a guide from flite test but it never seemed to handle as well as a conventional x-quad. I';m back with the X shape now using 15x15mm pine

[XH558]

That';s looking really cool.

Are you going to keep it ';au naturel'; or will it be getting a coat of paint?

Well I was going to paint it black as I did the Hex - but that was more about hiding the ply plates what with carbon arms and all ... but this has aluminium arms and I can';t really paint them - also I think the ply looks pretty cool and emphasises that ';home made'; look which I';m proud of ... so sod it .. it stays as it is     (that and I can';t really afford to be adding yet MORE weight  )

Nice work looks great! .  Good to see a DIY frame in the making.
Gav

Is there ANY other way 

[XH558]

That looks really cool, a lot more professional than my home build attempts :-) How do you work out the length/angle of the arms? I built a h-quad based on a guide from flite test but it never seemed to handle as well as a conventional x-quad. I';m back with the X shape now using 15x15mm pine

I looked at images of a QAV 500 on';t t';internet ... printed out a load and poured over them - then realised that I could see things in the pictures I knew the dimensions of ... Deans connectors - Naza - GoPro - 10" props ...

So I measured those on the pics and scaled it from them. So angles of the arms come from that process and arm length sort of came out at 20cm (ish) - well I didn';t think that looked right - so using the age old principle of ';If it looks right it IS right'; I made them 22cm     

Drew it on Corel Draw and printed the plates out onto A4 (adding red register lines if it needed sheets joining) - Using Corel Draw is mustard - you only need to draw one corner accurately then you can cut/paste/mirror that to the other 3 corners and know they are all the same 

Then I spray mounted those directly onto the ply

Then cut them out roughly on the scroll saw

Then drilled the holes through all the plates together - then bolted them and shaped them when they were all held firmly using the disc/belt sander - It';s amazing how all the curves I use are exactly the same as the curve on my sander belt     

It is by no means perfect and not very accurate in that the shaping isn';t perfect and the lightening holes are all over the place ..  but the other age old principles I use are .... (1)';can you see it when it';s in the air?';.... & (2) ';will it fly?'; ....  If the answers are No to (1) & Yes to (2) what the heck 

I jus'; loves de fettlin';  ::)

[Gav]

Is there ANY other way 

No not really if you have the time, tools and skills.  All good fun. 

Now hurry up and finish it

[XH558]

Now hurry up and finish it

Some sage advice once given to me many years ago....

There was a young bull and an old bull in a field passing the time of day ... suddenly the young bull sees the farmer turn some young heifers out into the next field .... "Quick" ... says the young bull to the old bull ...."Let';s dash over and screw a couple" ..... "No" says the old bull .... "Let';s amble quietly over and screw the lot"

Take your time.... enjoy the fettlin'; .... no hurry   

[Gaza07]

Thats looking very good 

[XH558]

Well I typed a really good next post about 6 hours ago and tried to add a small movie attachment which got refused and I then pressed the wrong buttons and lost the lot    (Can you add movie attachments??)

So - I';ve gone to the bother of uploading it to YT so you don';t miss a real treat 

So here I go again ..... more on the build .... not quite a one day build as on the other thread ... but using the ';old bull'; process of slowly and quietly I';ve done the next bit ... ::)

I was about to join up the 2 ';dirty'; plates and the arms then had an epiphany (a flash of unusual foresight  )  and I realised that if I bolted it all up and then fired up the NAZA and my motor rotations were wrong I wouldn';t be able to get to the esc connections to reverse them ....

So I jury rigged the NAZA to the unbolted but connected motors and arms and got the rotations right ... then bolted it all up.

2 things spring to my mind/attention at this stage of the build ..

1) 3mm is perhaps not the most versatile build material ever ... as I am wont to think  :embarrassed
It is clear that the lightening holes may have made the plates lose some of their structural integrity.... whilst it';s perfectly strong and rigid in it';s bolted up form it';s a bit ';wavy'; ... see pics below 

2) The orange flexible bobbins (used on the original QAV 500 are totally brilliant and the 4 point mounting of the completed ';dirty'; plates to the ';clean'; plates above them is just excellent ... see the uploaded YT demonstration at the end 

You can also see in the pic of the motor mounting why my Dremel expired (see the ';Magic Smoke'; thread  )  I thought that adding the motors to the tops of the aluminium arms would be A) too easy and B) look a bit naff.... so I cut out a load of aluminium (RIP Dremel  ) and dropped the motors into the arms - thus neatening things up as the wiring just disappears mostly unseen down inside the arms 

It';s not by any means perfect - and the accuracy of some of the cutting leaves a lot to be desired - but it';ll fly and I';m sure it';ll look ok ... overall I';m quite pleased so far 

Moving quietly on ... wiring - loads of cable ties & electrics next 





Orange flexible mounting bobbins

[Gaza07]

I';m afraid movies are to big for us to host and there is a limit to the upload size the server will accept 
You have done what you should do upload it to you tube then use the share link in your post 

[XH558]

I';m afraid movies are to big for us to host and there is a limit to the upload size the server will accept 
You have done what you should do upload it to you tube then use the share link in your post 

Thanks boss ... I shall sleep much easier tonight now   

[XH558]

Ok - well it';s pretty much finished and tonight was 1st attempt at a flight without FPV just to see where we are at. It';s a bit windy - but then that';s Cornwall and I know the Naza can cope with it ok.

I know convention dictates that maidens are supposed to be videoed etc - but sod that for a game of soldiers .... you aint seein'; it fly till I know it flies ok

It';s 1394 gms AUW - (3lbs 1oz in old money)  and looks pretty good - I love the design and it balanced on C of G at first try - didn';t have to move the battery at all.

So ... to the problem that';s came up right off the bat ...

It took off straight as a die and hovers very well ... but almost immediately the front left (number 2 clockwise) motor/arm keeps dipping in a fidgety manner while hovering ... then suddenly it just cut and she just fell to earth on that front left corner.

No damage as I was deliberately over the lawn and not very high.

I powered up again and it just started as normal - but the dipping continued on that same corner. So I quit while I was ahead and have come on here to get the perceived wisdom of why this might be.

4 x brand new Emax 2213 935kv motors - 10 x 4.5 props (balanced) - 4 x previously used DJI OPTO 30 escs (flown very successfully on my Hex).

Someone else on the net has described the exact same symptoms with another flight controller and that was put down to a dodgy bullet connector or solder joint.

Ideas - thoughts - reasons ????

[XH558]

edit ... later  ... decided to dive in and have a look ... the escs are a bu**er to get to as they are sandwiched between those 2 dirty plates - but you only have to undo the 4 bobbins to separate clean from dirty - so I did that and then made the cooling holes over the one esc a little bigger 
Unplugged the motor from it - took out the one arm and removed the motor ....

It seems that wire insulation inside the arm was broken on all 3 wires near where it exits to go to the esc and I think I know what did that ... when I put through the bolts that clamp the arms in place the wires must have got trapped by the bolt against the arm side .... also one of the bullet connectors was a bit dodgy ...

So - in for a penny - I';ve replaced all 3 wires and all 3 bullet connectors    Why I suspect the arm mounting bolt was when I was rebuilding with the new wires one bolt was a bit difficult to get in - like something was in the way -  so I looked through the lightening holes in the arm and saw that all 3 wires were well over to one side - where the bolt was - I moved them away with some needle nosed pliers and the bolt just dropped in 

Not run it yet as there';s some more reconstruction to do  ... i.e. rejoin clean to dirty .... but I suspect that may have been it ... too much of a coincidence.

We';ll see 

[XH558]

I seem to be talking to myself in this thread .... but anyway ....Yes - that WAS it ... the wires with missing insulation ...all rebuilt and now you can see some footage 

Short film in the garden - very windy (standard for Cornwall ) - and I had the FPV camera running to the helmet although I';m certainly not trying it out for real in the confines of the garden   

I just had it running to see what affect it had on anything ... there is a lot of crackling on the sound track ... especially when I turn back towards the workshop @ 1:15 - 1:17 ..... you can see the helmet lying on the decking 

Very impressed with the flexible bobbin mounts - no sign of any shake on the GoPro do you think??

In my view not as stable as the Hex .... but still eminently flyable 

Well chuffed - as a clone it';s pretty good - and all home made  ::)

QAV500 Clone

[teslahed]

That';s a very impressive machine by the looks of things - loads of space to mount all your FPV equipment as well.

The gopro video looks very smooth - no jello, just a bit of twitching from side to side which should disappear when you';ve had time to tune the DJI NAZA properly. For diagnosing vibrations try and record a short video at maximum resolution because that tends to show up problems better than at 480p.


Edit - also for diagnosing  vibrations, attach the gopro directly to the dirty plate. I suspect your clean plates will mask quite a lot, making finding the vibrations and getting rid of them harder.

Your propellers look like the weak link in your design at the moment. Get some RCtimer full carbon props on that thing straight away - they will make a big difference to the performance, anything less would be a waste on an aircraft like that.

http://www.rctimer.com/index.php?gOo=goods_search_list.dwt&gcat=198&gtype=

http://www.rctimer.com/index.php?gOo=goods_search_list.dwt&gcat=191&gtype=

you can get better props elsewhere if you have more money to spend but the rctimer ones seem very good for the price. I wouldn';t fly with plastic props now.

[XH558]

Now I';ve got round to adding a set of dog';s breakfast legs/skids ...a pair of Trex 450 legs and some 5mm wooden dowel .... keeps the props away from the floor and gives a nice stable landing platform.

I';ve also received and fitted the GPS antenna folding doohickey - very impressed - one screw holds it and you unscrew the knurled collar and it just folds down.
http://tinyurl.com/qhqqbf7

Also in the folded antenna pic you can see I';ve received and fitted a voltage regulator gizmo from HK as recommended by Teslahed.... don';t know what it does (yes ok it regulates voltage ) but don';t know what that ';does'; in the scheme of things .... but it was recommended so in it';s gone ....

I';ve also added the simple OSD device from HK on the helmet - so now I can see battery voltage and time elapsed.