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help designing carbon mini qud to be sold for around $60

rcflyer729

fpv and rc planes
#1
help designing carbon mini quad to be sold for around $60

Hi my name is Luke I have been flying rc stuff for around 7 years. I am 16 and got into fpv around a year ago and I got my fist mini quad around July 2014. So I bought an emax mini quad and really like it but I have gotten pretty good at it and wanted something better and smaller because the emax quad is kinda big although you can use 6 in props. I had two options I could get a blackout or something like that or I could try to build something out of carbon. I decided to build something. I was thinking why do nice carbon fiber mini quads have to be so expensive the cheapest I know of that you can get is $100 so why not make something affordable and good quality also I spent nearly $200 in parts for the one I am making. I could of just got a blackout but now I can try sailing them as I have enough to make 4 quads and would get more stuff to make more quad if I can sail. So I received my carbon today. I bought one sheet of 1.5mm carbon for the main parts and a sheet of 3mm for the arms. I do a lot of designing on auto cad as my Dad has it for his work I have access to it :). So I spent a couple days while I was on vacation to designed a 220mm mini quad just small enough to fit 5 in props and carry a mobius. If this goes well and I am able to make some money on this I plan to make a 300mm mini quad. I plan to be sailing these on ebay at first and maybe get a website if all goes well. The reason I am posting here is because I need help finalizing the plans. Please do not hesitate to give your advice remember I am designing this for you all to buy so please any advice would be greatly appreciated. A couple of questions that I have are how do I know what size my mini quad is like 200mm or 250mm quad? I plan to mount the battery on the top plate with the mobiuse as that leaves room for the flight controller on the bottom plate and a video tx. Should I make a ccd camera mount like most quads have? I am going to use 36mm stand offs black I already ordered them. I will be using all stainless hardware and lock nuts. I am going to try to cut the carbon using a drimel drill press with a grout cutter bit any advice other than where a mask I already know that:). In the plans I have 3 different arm designed and I would like your advice on which one I should use or If I should do a total redesigned. The pdf I made is 11x17 so If you want to print it to get a good look at sizing you will have to have an 11x17 printer. I got my parts cost down to around $30 per frame and depending on how much time it takes me to cut out I will try to sail for $60.

the plans
View attachment mini quad.pdf

My you tube channel
https://www.youtube.com/channel/UC9B9SkoW6roKZ02VZNrOM5Q

video of me flying my mini quad

video of cutting carbon the way I am going to try.
https://www.youtube.com/watch?v=Sm7LTKsI8IY&index=5&list=WL
 
Last edited:

Cyberdactyl

Misfit Multirotor Monkey
#2
Hi,

I made my mini from cutting it completely with a rotary tool. I used a Proxxon, which is basically similar to a Dremel. I also used the Proxxon drill stand. One other item I would recommend getting, is extra abrasion disks. The disks I link to are decent quality and around 15% the cost of buying them from your local hardware store. They wear faster than the standard disks that come with a Dremel, but are MUCH less brittle and maybe 0.02mm thicker.

In the video you link, it shows cutting the CF with an abrasive grout bit. They do work, but will wear out after cutting around 24" of 2mm CF to the point where you are pushing the CF so hard against the bit that heat starts becoming a problem, if you don't snap the bit first. Here is a bit that worked well for me. I went through one and started using another before I was done.

I primarily used the bit for drilling holes or making tight radius turns or where the abrasive disk was inconvenient or impossible to reach. Also, for straight cuts, the disks make much nicer cuts, where the bit cut will tend to be slightly wavy, no matter how much care you take, or use a fence. CNCs can pull off straight cuts with a bit, humans simply can't do the job near as well. I used a make-shift fence and the disk for all my long straight cuts. That's why my mini has an angular look.

You'll also want to have a shop vac sucking a couple of inches from the cutting. I also used a fan a few feet away blowing the air in a direction away from my face and towards the vac intake. You don't want to be breathing the dust. I didn't use plastic gloves much of the time, and when I got the dust in places like the cracks on my knuckles and fingers, they would later have irritation much like a slight itchy sunburn. If you do get the dust on your hands, wash them with COLD water to prevent your skin's pores from opening.

Good Luck!
 

x0054

Senior Member
#3
If you do start to sell these in any volume (10+) you may consider getting a CNC machine. I think they are relatively inexpensive nowadays, about $600-1,000. You should also add to your cost calculations about $6-10 or so worth of bits, the bits do ware out quickly. I think Twitch on this board would be able to tell you more about this, he does a lot of CNC work.

As for your design, it looks cool, but I would recommend making the arms a little longer and have them mount deeper into the main body of the quad, so you have better leverage. I would also think about using lighter hardware, like aluminium or plastic. Over all I think you have a very nice design, but it's been done before :)

http://www.ebay.com/itm/QZO-Mini-Qu...519?pt=LH_DefaultDomain_0&hash=item1e92747cb7

I actually have the quad above, and I crashed it into rocks going 30+MPH, and it's still alive. The motors, not so much, but the frame is alive and well. The main problem with China made stuff is consistency of quality. My frame was perfect, but other people had some bad carbon issues with those frames.

So, if you can make it out of superior CF and provide very good quality, you might do quite well. The CF they sell from china on Ebay is OK, but it's not the best. I had a few small delaminations on the quad I made from scratch as well. Where did you get your CF? I have been looking for a better supplier.

In general a lot of people are getting into FPV racing now. If you can design a quad for that, you should do well. Mostly people are using 5 inch props, because that's what many racing groups require, with KISS or similar ESCs, and the Sony cameras for board camera. Tilt motor mounts are very much in now as well. Those are some ideas I would look at.

The frame you designed is a good frame, but you need to capture the imagination and have the IT factor. That's just my opinion :) But a high quality ZMR alternative would probably be very popular as well.
 

Twitchity

Senior Member
#4
x0054 made some good points about the design/selling/what people are looking for in a racing quad.

As far as cutting goes, I wouldn't want to cut that many pieces by hand, especially carbon fiber. For a one off personal projects like Cyber does the hand cutting method is a viable option, but if you plan to cut anymore than a few frames I'd look into other alternatives. There are quite a few places that will take your CAD file and cut the parts for you, but I'm not sure how much they would charge. The other alternative is to pick up a CNC machine. I personally use the Shapeoko 2 and don't have any complaints about it https://www.inventables.com/technologies/desktop-3d-carving-cnc-mill-kit-shapeoko-2. For the price of the machine, you can't really get a much better deal, and the machine produces very consistent cuts. The only thing I would do is upgrade to the quiet cut spindle as the little cheapo dremel is garbage.

For my cutting I use carbide router burrs anywhere between 1.4mm to 1.5mm (depending on what the seller has in stock). I purchase all of my bits from a seller on Ebay named "drillman1" who is located here in the states, has fast shipping, and so far I haven't had any problems with the bits he sells. These are the current bits I'm using for my cuts http://www.ebay.com/itm/380559667141?_trksid=p2060778.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT. These do wear out fast so expect to replace them often. If you're cutting by hand it may not be as bad, but on my CNC where it's programmed I can tell the bit is worn out more and more with each set of cuts it does. I typically program the gcode to cut all of the bolt holes first and the first 10 or so are perfect, but after that each hole takes a little filing out to be the correct size. For this I use a diamond round file with a piece of tape stuck to it at the correct depth it needs to go down to to get the hole the correct size. I can typically get the frame pieces cut with one bit or two arms cut with one bit before it needs to be changed so I'm looking at a minimum of 3 bits per frame. If you end up going the CNC route I can help you with cut depth/speed/stepdown settings, but for now that would do you no good for hand cutting.

I would also like to know where you're getting your CF from if you don't mind saying. If you do I completely understand. As far as I know the only place in the US that sells CF is DragonPlate, but they are of the premium price. All other suppliers are typically based out of China, but not all are bad.

If you do plan to follow through with this, and are set of cutting the pieces by hand, I would probably recommend that you create a template to use so you know all of your holes are drilled in the correct place. This would be beneficial if someone breaks an arm you know the replacement ones you sell won't have any problems bolting to the frame; you could be 1/2mm off with one of the holes which could cause some frustration on the assembly.

Just one quick observation on the design. It looks like you have two different spacing for the FC mounting location; one for a Naze32 or similar and one for a KK board. It looks like the holes for the KK board need to be spaced further apart from left to right if that's what they are for. I can't remember if this is right, but I believe the KK boards use a 45mm x 45mm spacing for the holes. My eyes may be playing tricks on me, but it seems like they need to be separated a little more in one direction.

If you have any specific questions feel free to shoot me an email (its in my sig) or post in the thread.
 

rcflyer729

fpv and rc planes
#6
I know that a cnc machine would be a lot better I just don't have the money to invest in something like that I at least need to sail a few frames and see how it goes before I do something like that
 

rcflyer729

fpv and rc planes
#7
Sorry about the hole seizing two of them were just not supposed to be there at all and the other two were for the standoff I will update the plans right away thanks a lot for the help I am sure I will have more questions for you if you look in the thread I replied to x0054 with the link to the carbon that cnc machine looks like a really good deal I will look into it
 

jhitesma

Some guy in the desert
Mentor
#8
I don't want to discourage you. I really don't. Quite the opposite in fact. So keep that in mind reading this and remember it's meant as constructive criticism ;)

Short version: I think you need to think about your business plan a bit more.

This is a great idea and something that I think would be a great start towards a life of entrepreneurship which is something I'm personally a huge fan of encouraging. But I think you need to think of it more as a business instead of worrying about keeping the price low. If you come up with a good design and are willing to put the time and effort into producing them - you can set the price higher and actually have something that could be a self sustaining business.

But. You need to think about all of the costs involved - and the biggest that I think you're neglecting to consider is your time. That's a BIG time investment you're going to have in cutting these. And your time is valuable. I don't care if you're 10 or 60, skilled or unskilled, if you want to make a business out of this you need to remember that your time is valuable and needs to be accounted for. And you'll be spending a lot of time cutting these at first. Cutting CF isn't easy and takes time to do well. There's also the cost of bits and wear and tear on your equipment. Plus your health - you'll need to account for a face mask and gloves if you're going to be doing more than one or two of these. Those are corners you DO NOT want to cut as once you loose your health you can't get it back and once you stop valuing your time you're on a road to disappointment.

I guess what I'm trying to say is - step back for a moment and look at the big picture. Try to think of every cost you're going to incur, your time, materials, wear on your equipment, bits, electricity to power the equipment....think of it as an actual honest business that needs to pay all it's bills before it can show any kind of profit. This is a great opportunity you have and you can really make the most of it if you plan it all out.

Don't forget to plan for the future with it too. What if your design gets popular and demand increases? You won't be able to keep up with cutting them by hand. Look into cutting services or plan on saving your profits to put towards a CNC to grow your business. And what about suppliers - goodluckbuy has some deals but they're a risky supplier to base a business on. What if your next batch of CF isn't the same. What if it's no good? It's usually worth paying a bit more for a reliable consistent supplier than risking your business on the cheapest supplies you can source.


Again, I don't want to discourage you. I want to see you succeed! Talk to some local business owners and see if you have a small business development center in your area that can give you advice. There are a lot of resources out there if you look for them and are willing to take advantage of them. Just don't get hung up on price. If your product is good it's worth more than $60. And if it's really only worth $60...it's probably not worth your time and effort to push it. At least that's my $0.2 (adjusted for inflation apparently!)
 

rcflyer729

fpv and rc planes
#9
Thank you very much for your honest reply It was very helpful. Here is my current plan. I will cut one frame out for my self do some testing and cut the other 3 out. than I will try to sell them on ebay for round $60 to $70 just to see how it goes even if I am not really making money on it. Than I will get some more carbon probably form a real supplier I have one lined up xccomposites. And I will fix a fixed price. I defiantly want to have the price under $100. Next I will look into a cnc which my Dad is quite interested in as he could use it for engraving phenolic nameplates since my Dad is an electrical Engineer and he has his own business making control panels. So I can probably get him to help me buy it. Than I will try to setup some kind of website while continuing to sell them on ebay.
 

rcflyer729

fpv and rc planes
#10
I am really interested in that cnc you recommended. I have a few questions about it. My carbon I get is 400x500mm and I know the cnc is to small to cut that all at once so my question is is there room to cut half and move it over and cut the other half. I know you can upgrade it to bigger but this would just be more to the cost. The upgrade spindle is like $200 can I just go down to lows and get a good router and put it on?
 

Cyberdactyl

Misfit Multirotor Monkey
#13
One aspect to go along with jhitesma's comments.

I'm fairly certain CF can't rotary assisted, "hand-cut", to match the cutting quality of a CNC, most especially if you don't have many hours (>20) of practice. I took around 6 hours (not all at once) cutting out the CF for my mini, and it has very few curved lines. A percentage of that time was setting up make-shift jigs and fences. Also, I would suspect, even after you've developed a streamed lined method and production setup, you will still have 2-3 hours per frame from looking at your pdf with its numerous curved and tight inside cuts.

IF it is only for yourself, use good quality CF. But if you are indeed going to try and sell rotary assisted, hand-cut frames, I would suggest beginning with fiberglass or G10. It's MUCH less expensive. Anyone that has seen a CNC cut frame will instantly recognize the difference between a hand cut, i.e., not as "pretty" and a CNC cut frame, so there's no need to use expensive materials, since you probably will not be able to get/demand a premium price for the frame, no matter what material is used.
 

jhitesma

Some guy in the desert
Mentor
#14
does anyone have advice as to what vibration ball dampeners I should use on the mobius mount
I'd say skip them. Mobius cams are so small and light that dampeners really don't make any difference with them. I've mounted mine with and without on the same frame and really can't see any difference. Dampening only works if you have enough mass on the isolated section. So unless you're going to mount the battery on the same isolated part as the mobius the dampeners are really a waste of money.

If you do use them go with the smallest softest ones you can find, but don't expect them to make a real difference.
 

Twitchity

Senior Member
#15
I am really interested in that cnc you recommended. I have a few questions about it. My carbon I get is 400x500mm and I know the cnc is to small to cut that all at once so my question is is there room to cut half and move it over and cut the other half. I know you can upgrade it to bigger but this would just be more to the cost. The upgrade spindle is like $200 can I just go down to lows and get a good router and put it on?
You should be fine with sheets in the size of 400x500mm on the Shapeoko2. The front and back are open so as long as it fits within the two Y rails you'll be set. The usable cutting area on mine that I like to use is 11" x 11". The cutting area is larger than that, but not by much. I like to keep all of my designs within that size so I know the machine won't reach the end of an axis while cutting and mess up the entire process. Once you've cut out all the parts you can just simply slide the CF sheet up/down and begin your next set of cuts.

I also use a 1/4" thick MDF board that gets bolted down to the Shapeoko's waste board so I don't have to ever replace the 3/4" thick stuff, and only need to replace the 1/4" thick MDF every so often. I can get three squares that are 15" x 15" out of a quarter sheet of MDF at Home Depot that costs around $7 and lasts me many cuts since I can turn them around and flip them over to get to unused space.

You are correct about the router. The DW660 http://www.amazon.com/DEWALT-DW660-Cut-Out-Rotary-Collets/dp/B000051WQX was a real popular router to use and I ended up using one my dad found at a garage sale for $5. It worked perfectly and had plenty of power, but man was it loud... I'm sure the neighbors didn't enjoy hearing the router going for 3+ hours at a time, and I sure didn't enjoy the sound in my house. With the quiet cut spindle I can carry on a conversation with someone while standing right next to the machine as it cuts if I'd like to. I would say it's no louder than your everyday electric drill.
 

rcflyer729

fpv and rc planes
#16
thanks I am considering getting it. Would there be any reason getting the nice $1000 version aside from getting the spindle? I think I would go with the dewalt rotary tool because we have a work shop a good ways away from our house and not to close to neighbors so noise is not really a problem. Does the cnc controller turn the power tool on and off or do u just do that manually?
 

Twitchity

Senior Member
#17
The only benefit to the $1000 version (to me at least) is it includes the quiet cut spindle. I don't need an enclosure for my arduino board; I can use a plastic container with a few holes cut in it if I wanted to. The wasteboard with clamps sounds nice, but a few dollars at the hardware store bought me some threaded inserts and bolts, so not I just bolt my 1/4" MDF down and use the bolts for an L extrusion of aluminum to hold the part down.

The clamp is to just keep the sheet flat on the cutting surface. I use double sided tape to actually hold the CF down and keep the pieces from moving around when cutting. This method has worked great for me so far and is easy to setup.

With the quiet cut spindle I believe you can wire it directly to the board to turn on/off when a job begins and ends. I just turn my on/off manually. I typically know about how long each cut takes so I'll check the software when I feel it's getting close. Worst case is the spindle is running for a few minutes doing nothing.

Another thing with the dewalt router is the weight. If you browse the Shapeoko forums they recommend you purchase the z-axis upgrade if you're using a router due to the weight difference. I however did not purchase this upgrade and it worked just find for the time I was using it, but I could see why they would recommend that upgrade given the weight of the router.

One last thing I would recommend if you go through with this kit one day is pick up some M5(?) helicoils for the aluminum extrusions. I believe the hardware is M5 for this thing, but I can't remember. The kit requires you to use the supplied tap and thread holes into the ends of the aluminum extrusions to bolt on brackets. The bolts they give you don't go into the aluminum that far and are extremely easy to strip when assembling/fine tuning the height adjustments for each rail. The helicoils are nice since they essentially re-thread the hole with steel threads allowing you to tighten the bolts down without worry of stripping the holes. If they included longer bolts for this it probably wouldn't be a problem, but unfortunately they don't.
 

rcflyer729

fpv and rc planes
#18
I ordered those bits from drimel1 on ebay and am waiting for them to come when they come my plan is to cut an arm out and see how hard it is and how the finished product turns out. The arms are really small and I have a lot of the 3mm carbon so I can't really wast it by cutting one arm. If it goes well I will cut a frame out if not I will look into other options. One question I have is which arm do you all think would work the best out of the three I have in the plans?
 

rcflyer729

fpv and rc planes
#19
Me and my Dad have been doing some research and we found that there is shapeoko 3 coming out and is available for preorder. It is $900 plus a hundred for the router. It looks a lot better for what I am doing as the cutting area is 425mm x 425mm which is a lot bigger than the shapeoko 2. Also it looks just all around better designed and they say it only takes 2 hours to put together. What do you think. What software do you use to connect to the cnc machine and layout your designs.
http://www.shapeoko.com/
Thanks for all the help!!