Welcome to PhantomPilots.com

Sign up for a weekly email of the latest drone news & information

structural engineer

Discussion in 'General Discussion' started by auck, May 5, 2013.

  1. auck

    Joined:
    Feb 20, 2013
    Messages:
    275
    Likes Received:
    0
    Location:
    San Jose, CA
    looking for a structural engineer who can reinforce the phantom's shell without adding too much weight to it. It sounds like the common theme with the shell and stress fractures are due to upgraded propellers putting more stress on the shell than it was designed to handle.

    is there anyone out there who has any idea as how to reinforce the motor mount area of the phantom for those of us who have upgraded to more powerful engines and stiffer propellers?
     
  2. BadWolf

    Joined:
    Mar 26, 2013
    Messages:
    61
    Likes Received:
    0
    Location:
    Fremont, New Hampshire
    Here's my idea.

    I'm waiting on a piece of carbon fiber to strengthen the motor mounts. I'll be cutting a piece of 3mm thick carbon fiber into a 1-3/16" dia. disc. I'm going to drill 4 .250 dia. holes in the same pattern as the motor mount lugs. The carbon fiber disc presses onto the motor mount lugs strengthening them. It's either going to strengthen the lugs from cracking, or the motor screws may pull through the lugs. Well I'm not counting on the latter.

    I may have a prototype ready by tuesday, so you can see what I'm talking about. Right now I only have enough carbon fiber to make 2 discs. I ordered more, but I dont have an arrival date. It's from Ebay and coming from England so it may be a while.
     
  3. Audaciter

    Joined:
    Mar 18, 2013
    Messages:
    724
    Likes Received:
    2
    Location:
    Sunnyvale, California, USA
    I would be interested to see what you come up with. The motor mounts definitely need strengthening .
     
  4. auck

    Joined:
    Feb 20, 2013
    Messages:
    275
    Likes Received:
    0
    Location:
    San Jose, CA
    do you think a coating or two of that plastaid you mentioned in another post will help? just around the mounts on the inside of the shell... sure it will make it a bit thicker, but wouldn't it be more resistant to stress?

    or how about finding a metal tube of some sort to act as support?
     
  5. BadWolf

    Joined:
    Mar 26, 2013
    Messages:
    61
    Likes Received:
    0
    Location:
    Fremont, New Hampshire
    I think the Plast Aid would work well on an already cracked shell. It starts out as a liquid and gets thicker as it cures. I used an eyedropper to cast the supports for the battery system I'm making. When it gets thicker you can mold it by hand. For molding a support I think it would be too messy to work with, if you mess it up, it's all over.

    I thought about taking some 1/4" ID aluminum tubing and cutting it to a 3mm lengths and pressing them onto the lugs. I thought it would give more support to the lugs, but cutting them into exact 3mm lengths without distorting them is difficult.

    Then I thought about the carbon fiber disc that would tie all the lugs together for better support. There are several options, but I think the carbon fiber disc would be the best. If you crash and destroy the shell, you can just pull off the carbon fiber discs and put them in a new shell.

    If you decide to use the Plast Aid practice useing it first, just to see how it works. There's also another plastic product called Polymorph sold on Ebay. I would not use it. It's plastic pellets when put into hot water it turns into a putty like plastic and hardens as it cools. It turns putty like at 60 degrees celcius or 140 degrees farenheit. The heat from the motors would most likely turn it back into a putty.
     
  6. BadWolf

    Joined:
    Mar 26, 2013
    Messages:
    61
    Likes Received:
    0
    Location:
    Fremont, New Hampshire
    I completed the first prototype disc. All went well except for the hole size. The motor lugs may have a slight taper to them. With the .250 dia holes the disc starts to go on, but will not go all the way down. The next one will have 6.5mm holes which are .255 dia. I need to buy some 6.5mm drills now. I may have a working prototype by friday.
     
  7. mmcbain

    Joined:
    Apr 14, 2013
    Messages:
    20
    Likes Received:
    5
    Location:
    Melbourne, Australia
    I've said this in other parts of this forum, but here goes.

    I think you're over-thinking things. The DJI Phantom is a consumer-grade entry-level quadcopter. It is the first 'serious' quadcopter available to first-time RC pilots, which is why it continues to sell so well. Hundreds of thousands have been sold since the beginning of this year. However, the RC quad hobby for the past few years, particularly since the advent of LiPos and advanced flight controllers, has been the domain of 'hobbyists', people for whom soldering, sawing, riveting, and just building things generally are accepted as being how things are. The first reaction of those people to the Phantom is 'how can I upgrade this', whereas the newbie says things like 'how can I use this for aerial photography'.

    The Phantom is a small 330-class quadcopter with a plastic shell as its primary structural component. We know the shell reacts very badly to Loctite, that larger motors quickly cause fatigue cracks at the ends of the arms, and that the stock propellers exacerbate rolling shutter effects because they are made of the same soft plastic as the shell, and therefore flex a lot. The Naza-M also has some fairly seriousl limitations as well. It's not a 550, it's not made of carbon fibre or aluminium, and its performance envelope is noticeably conservative.

    If you want a stable aerial platform that seriously kicks ***, buy one. No matter how much you might tweak the Phantom, it has inbuilt limitations that will disappoint efforts to turn it into some kind of monster flying machine.

    Michael McBain
    Melbourne, Australia
     
  8. BadWolf

    Joined:
    Mar 26, 2013
    Messages:
    61
    Likes Received:
    0
    Location:
    Fremont, New Hampshire
    I like the Phantom. I want to make it better. Thanks for your 2 cents worth.
     
  9. auck

    Joined:
    Feb 20, 2013
    Messages:
    275
    Likes Received:
    0
    Location:
    San Jose, CA
    i agree. this is like buying a civic and fixing it up to get the best performance you can. of course it will never perform like a Lamborghini, Ferrari or one of them "super cars", but this isn't about the civic being a super car. It's all about how much performance i can coax out of it. :)

    i do believe there is a post on this forum along the line of "pimping out your phantom" but in the mean time, has anyone come up with another way to reinforce our phantoms?
     
  10. c4nuck

    Joined:
    Apr 30, 2013
    Messages:
    6
    Likes Received:
    0
    Location:
    Port of Spain, T&T
    My initial thought for reinforcing would be to add a knee brace from the motor down to the landing gear for rigidity. I think the strength is there in the shell, you need stability on the force of upgraded motors. I would be tempted to get a thin strip of aluminum, mount it to the bottom of the round sheel motor housing, and bend the strip to suit to tie into the landing gear.

    Adding material to the shell to stregthen it may actually do the reverse of what you're after, extra weight, extra load on the arm.

    My .02

    Ill post a sketch later on of what I'm talking about, makes perfect sense in my head, but in wirting may be a mess.