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Quad copter death

Bobo

Senior Member
#1
Hi,
I had just finished building my first SK450 quad copter. I thought I should fly it in the front yard so I did. I did two flights to tune out my quad then something unfortunate happened today. I went to go and fly it and it was flying nicely until the battery on my 9XR transmitter died and my quad went hay wire and flew forward and down just missing my neighbors house and it took a dirt nap. It had snapped an arm right in half and ad cracked another. Luckily i didn't break any of my electronics. I have three choices which I have to chose from.

A. Buy more arms (2 arms cost almost as much as the frame itself.)
B. Buy another Frame
C. Buy a tricoter frame because I was planning to make a tricopter plus I like tricopters

So could you guys help me out. I am a beginner at this RC stuff.

Thanks
 

xuzme720

Dedicated foam bender
Mentor
#3
I would go with B. You'll have your replacements and some spares to boot. Plus, it's probably easier to learn to fly better before trying to go tri...
 

Bobo

Senior Member
#4
Also I was planning to upgrade my KK2 board to 1.6. Will it automatically do a factory reset or will it keep my settings.
 

cranialrectosis

Faster than a speeding faceplant!
Mentor
#5
Look hard at the AnyCopter or one of the other FT frames. Simply because you can use cheap 1/2" wood dowel from the hardware store when you break booms. You can also replace the wooden booms with CF, aluminum etc and alter the lengths.
 

xuzme720

Dedicated foam bender
Mentor
#6
CR has a point. I would still grab a second frame kit to use for parts on the 450, but grabbing a FT kit which is cheaper to repair while you are learning to fly and will make the 450 last longer as you get better on the Anycopter.
The new firmware will not save the old settings. You'll probably need to change them a little anyway with new FW anyway. Just write down all the settings you have now so you can set up the updated board as a starting point. Pictures of the menu screens might be a faster option than writing all of the settings down...
 

Bobo

Senior Member
#7
I am planing to buy some more arms because my dad says that the bat bone and the anycopter seires are a bit to costly right now. I also could you guys teach me how to use the failsafe on the d8r-II so I will be safe the next time the transmitter looses signal with the quad.
 

jhitesma

Some guy in the desert
Mentor
#8
I would suggest D - Build a frame from cheap materials so you can replace arms cheaply while learning.

Both the Anycopter and the Knuckles designs can both be built for just a few dollars and a few hours of work with nothing more than a few utility blades, a drill bit, and a small saw you can cut 1/2" dowels with.

1/2" dowels are dirt cheap (around here they go for about $1.70 for a 36" dowel) and all you need for the center places is some 1/8" plywood (but I suspect hardboard, acrylic, and other materials would work just as well.) I almost used circuit board material just so I could make the plate double as a power distribution plate.

Just download the plans and cut out an anycopter center plate - the shape doesn't have to be very accurate, the holes are what really matters. But even there you don't have to be dead on. I've learned with my budget knuckle build that these designs are VERY forgiving to minor imperfections.

Having replaced 5 arms in 2 weeks so far I really recommend an easily repaired wood frame to any beginner!
 

jhitesma

Some guy in the desert
Mentor
#13
Do you recomend just buying the knuckles hub
If budget is that tight I'd say just print out the plans and cut out your own, it's really not that hard. Just try to be accurate drilling the holes is the important part.

But if you don't think you can do it accurately then yeah, just ordering the knuckle hub and improvising on the motor mounts / landing gear is a good plan. Buying the 1/2" booms locally makes sense since you'll be needing them for replacements anyway :D
 

cranialrectosis

Faster than a speeding faceplant!
Mentor
#15
The Knuckle H Quad hub is a great way to go.

FT is in it for the hobby, so the plans are available online. You can print the plans on paper, lightly glue the plans to 1/8" hobby plywood from Hobby Lobby (make sure it is flat not warped) and cut the knuckles and hub out of the plywood with a sabre saw, bandsaw or scroll saw. Take care to get the grain of the wood right to prevent the grain from weakening the knuckles. You want the grain running perpendicular to the seam between the center rails and the motor booms.

The 1/2" square dowel should be easy to source locally. You don't want warped booms and the FT wooden booms are stellar product. Take care to source this well.

Use long zip ties or PVC or spare pieces of plywood for landing struts and run M3 screws through the booms or make mounts out of washers to hold the motors.
 
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jhitesma

Some guy in the desert
Mentor
#16
Regarding grain. It's good to pay attention to but not really strictly necessary IMHO. Plywood is often used for building wooden clocks because when ply is made the grain is alternated each layer which makes it more stable and as it grows/shrinks from temperature/moisture changes it maintains it's overall shape better. If you cut wood gears out of solid hardwood then when it grows/shrinks it tends to do so in one direction more than the other which can cause gears to jam up.

So in general grain with ply shouldn't be a big deal. However the 1.8" ply is only 3 layers. So 2 of those layers do have the grain going in the same direction (the two outer layers) while only the single inner layer is going the other way. So it is slightly stronger in one direction than the other.

To be honest I did NOT pay attention to grain when I cut my knuckles. I did when I cut my center plates since in the knuckle build video Chad specifically mentioned failures due to the batter pulling through when the grain was going one way vs. the other. My knuckles are cut the "wrong" way with the outside grain running parallel to the join between the center arms and outer arms. I've smashed my quad quite a few times often quite hard. I've broken over half a dozen arms so far and yet I've yet to break a single knuckle even though the breaks usually happen right at the knuckle joint.

So yes, it's worth paying attention to. But if you mess up I wouldn't scrap the knuckles just because the grain was going the wrong way.

If you do cut them yourself remember keeping the holes accurate is the most important part. When I did mine I used a center punch to mark each hole, then used a brad point drill bit to keep it accurate. I have this cheap set: http://www.harborfreight.com/29-piece-brad-point-wood-drill-bit-set-35837.html and while not great drills they are fine for hobby stuff and make drilling accurate holes in wood and plastic so much easier.

When I cut mine I also worried about the kerf of my blade way too much. I wanted to make my knuckles as accurate as possible and on the plans there's no space between them so using a normal saw blade would have lost accuracy due to the kerf. So I did it the hard way and just used a utility knife and patience to cut them out. If I did it again I'd use my bandsaw or even a coping saw. Loosing a bit of dimension on the outside of the knuckles from the blade kerf doesn't really affect things since it's the holes that everything lines up off of not the outer dimensions of the knuckles.