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Leg Joint Support - New Idea

Liger 1956

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I have read of the joint at the end of the Anafi's leg above the foot being a weak point and that some people having to resort to gluing it together after a hard landing which broke the clip. I did look at buying the 'Landing Leg Protectors, from Dirty J Designs but they wanted $13 to ship a $10 part to the UK. As I have a 3D printer I looked on Thingiverse, which is a depository for 3D designs, and found a similar thing. I printed it out but I was still not happy with the design and the fact that it was quite heavy and covered the rubber feet. As I print in ABS this would mean that I would have reduced friction between the Anafi and the landing surface.

It was then that my mechanical engineering design background took over and I decided to try to design and print a different version. Looking at the Anafi I found that the feet have cutouts that are tapezoid in shape (the long sides are not quite parrallel) near to the joint. I thought that I could use these to support the weak joint and after a number of prototypes where I refined the dimensions i have ended up with a design that I think looks good, should work and is lighter than other designs (each support weighs 1.4g - 0.05oz each). I would be interested in how much the Dirty J Design Leg Protectors weigh. I used an Acetone cold vapour smoothing process to remove the layer lines from the print and end up with a glossy surface. What are the forum members views on my design? Do you like it and do you have any suggestions as to how it can be improved?

OpenScad Leg Support.jpg Orange Supprt.JPG Weight 1.4g.JPG Leg Close-up.JPG Ready to Fly.JPG

Previously I have also designed a support for my phone that slips over the controller's arm and stops the phone coming lose at the bottom. When I removed the weights from the controller I found that it tipped over when set down so I created a verion 2 that has legs to prevent this. These work well and I am always looking for new things to 3D print.

Phone Supports.JPG
 
Wish you had posted this a week ago, I purchased the leg protectors from DirtyJ designs, and thanks to the taxman and Royal mail, cost me a small fortune by the time they added import duty and handling charges.

I like the look of your design, and like it more so in the orange.

As you know, I have your kicker plate and yes if you take the weights out it tips over, so big thumbs up for the redesign......

And I know your products always come out top notch quality :)
 
I have the Dirty J foot covers, I like that they’re slightly stretchy and hold all around.

Yours look like they’d be lighter, but stiffer and only provide support from the sides where it holds against force up and down, not the in/out along the arm and torques the foot and pops it out of it’s locating tab ( although the arm where the foot attaches acts like a hinge so turns that into a pulling down force your clip helps with ) or the yaw forces that will close the whole arm in one direction harmlessly, but in the open-arm-further direction will try and twist the foot off.

Maybe a ring that goes around the foot that slides up from the bottom and locks in place? You could probably remove a bit of plastic from the existing clip, turning it into more of a lattice, and use the equivalent amount of plastic to create a retaining ring for the bottom of your clip.

I think a ( small ) problem with both designs might be that the carbon fibre is stiffer than the abs or rubber whatever that the supports are made of, so the arm is still likely to break but be held together - I’d like to see the failure mode sacrifice the cheaper part.

Something weird like sacrificial prongs sticking out from the foot support, or springier ones like curb feelers, that bend on impact and reduce/spread/slow the force applied to the arm.

For the phone holder, you have to pop it on and off each time opening/closing the skycontroller, right?

I’d like to see a folding design for that, that attaches to the back of the arm, so that is glued or velcroed on, sitting on top of the arm when it’s closed. Open the controller and the holder on the back of the arm unfolds around the arm so they can poke up above it to retain the phone. Bonus points if it does this automatically just by opening/closing the arm with a spring or rubber band, but something that unfolds manually but isn’t a separate thing to lose would be a step up from the pop-it-off-every-time designs.
 
I have read of the joint at the end of the Anafi's leg above the foot being a weak point and that some people having to resort to gluing it together after a hard landing which broke the clip. I did look at buying the 'Landing Leg Protectors, from Dirty J Designs but they wanted $13 to ship a $10 part to the UK. As I have a 3D printer I looked on Thingiverse, which is a depository for 3D designs, and found a similar thing. I printed it out but I was still not happy with the design and the fact that it was quite heavy and covered the rubber feet. As I print in ABS this would mean that I would have reduced friction between the Anafi and the landing surface.

It was then that my mechanical engineering design background took over and I decided to try to design and print a different version. Looking at the Anafi I found that the feet have cutouts that are tapezoid in shape (the long sides are not quite parrallel) near to the joint. I thought that I could use these to support the weak joint and after a number of prototypes where I refined the dimensions i have ended up with a design that I think looks good, should work and is lighter than other designs (each support weighs 1.4g - 0.05oz each). I would be interested in how much the Dirty J Design Leg Protectors weigh. I used an Acetone cold vapour smoothing process to remove the layer lines from the print and end up with a glossy surface. What are the forum members views on my design? Do you like it and do you have any suggestions as to how it can be improved?

View attachment 2030 View attachment 2031 View attachment 2033 View attachment 2029 View attachment 2032

Previously I have also designed a support for my phone that slips over the controller's arm and stops the phone coming lose at the bottom. When I removed the weights from the controller I found that it tipped over when set down so I created a verion 2 that has legs to prevent this. These work well and I am always looking for new things to 3D print.

View attachment 2035
What about a ring to hold SC3 and phone/tablet with a neck strap ?
Something that could be like that :
2037
 
There are some free Anafi 3D files for leg holders to phone brackets

Leg protectors


And this one


And this

 
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There are some free Anafi 3D files for leg holders to phone brackets
I looked at those leg protectors and printed one out in ABS but I did not like the way that it fitted covering the rubber foot and it was relatively heavy compared to mine. It was also not easy to print well even with supports.
 
What about a ring to hold SC3 and phone/tablet with a neck strap ?
I had thought about adding a ring but I would rather have the ring attached directly to the controller. I believe that if the controller was dropped and a lanyard was attached to the phone support it might knock the phone off the support, but it would save the controller! I put down the controller whilst I am sorting out the Anafi and powering it up. Whilst I use a lanyard on my R/C plane transmitter it is because I hand launch some of my planes e.g. slope soarers and the lanyard gives some support whilst I am holding the transmitter with one hand.
 
I have the Dirty J foot covers, I like that they’re slightly stretchy and hold all around.

Yours look like they’d be lighter, but stiffer and only provide support from the sides where it holds against force up and down, not the in/out along the arm and torques the foot and pops it out of it’s locating tab ( although the arm where the foot attaches acts like a hinge so turns that into a pulling down force your clip helps with ) or the yaw forces that will close the whole arm in one direction harmlessly, but in the open-arm-further direction will try and twist the foot off.

Maybe a ring that goes around the foot that slides up from the bottom and locks in place? You could probably remove a bit of plastic from the existing clip, turning it into more of a lattice, and use the equivalent amount of plastic to create a retaining ring for the bottom of your clip.

I do not totally understand the point that you are making. My design holds the lower part of the leg tight against the upper part by locating securely in the trapezoid indetations on either side of the leg. The joint is then held tightly together and acts as one piece. Whether it would give full protection in the event of a hard crash I do not know, and I am not willing to test. I think that I would rather have the foot come apart or crack then the leg break into two pieces and pull the cables off the motherboard.

I think a ( small ) problem with both designs might be that the carbon fibre is stiffer than the abs or rubber whatever that the supports are made of, so the arm is still likely to break but be held together - I’d like to see the failure mode sacrifice the cheaper part.

Are we sure that the arms are made of actual carbon fibre and not just some sort of black plastic as they do not appear to have a great deal of torsional rigidity?

For the phone holder, you have to pop it on and off each time opening/closing the skycontroller, right?

Yes, you have to extend the arm slightly and then slide the mount over the thinner part of the arm. It can then be slid right down to the bottom of the arm.

I’d like to see a folding design for that, that attaches to the back of the arm, so that is glued or velcroed on, sitting on top of the arm when it’s closed. Open the controller and the holder on the back of the arm unfolds around the arm so they can poke up above it to retain the phone. Bonus points if it does this automatically just by opening/closing the arm with a spring or rubber band, but something that unfolds manually but isn’t a separate thing to lose would be a step up from the pop-it-off-every-time designs.

A folding design could be done but it may not then fit in the case that I have for the controller so it is not on my to-do list.
 
I have just been presented with the same dilemma - do I want to buy from Dirty J Designs for 23$ with delivery or do I just chop my propeller guards to make them into what you have just posted above :)) Please post 3d files!! I have 2 legs with a common problem I will demonstrate below.
photo_2019-11-09_10-21-11.jpg

And man, I've been using your SkyController arm with great success. Never had any problems with my phone popping off again!
 
Eric,
Sorry to hear about your Anafi having damaged legs. I am away from home at the moment but I will post my leg joint support .stl design.either late tonight (UK time) or tomorrow morning.
 
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You do not need leg protectors or anything.

You can fix that quite simply - remove the 3 screws which hold the bottom part of the leg, and lift it away. You do not need to undo anything else.

Then you will see a small tab which is plastic welded down (it is the thing which fills that vertical slot in bottom part of the leg) - the plastic welds are brittle and start having play in them, then finally break - causing the little tab to lift from its position.

Just epoxy that little tab back down in to position - it sits on two posts which position it, then once it has all cured, you can re-fit the leg and the end will be perfect like new.

I have just been presented with the same dilemma - do I want to buy from Dirty J Designs for 23$ with delivery or do I just chop my propeller guards to make them into what you have just posted above :)) Please post 3d files!! I have 2 legs with a common problem I will demonstrate below.
View attachment 3004

And man, I've been using your SkyController arm with great success. Never had any problems with my phone popping off again!
 
Not the QA department, but a very effective Leg Filler for those that haven't experienced the separation pictured in post #10. May be proactive for those with leg extensions @ insignificant weight addition.
Well Done Liger 1956!(y)
 
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I bought the Dirty J Designs protectors.
Anyone think they will significantly affect the flight Dynamics? My first barebones test flight with them on had me thinking the Anafi was louder...which makes sense if the motors were having to work harder.
Don't know, just kinda nervous about it even though they seem like a good product.

Sent from my SM-N970U using Tapatalk
 
I have had them on my two Anafis for over 16 months with zero issues. Best things I have ever bought for my Anafi. Also love his tablet holder on the RC. Top notch products in my opinion.
 
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I have had them on my two Anafis for over 16 months with zero issues. Best things I have ever bought for my Anafi. Also love his tablet holder on the RC. Top notch products in my opinion.
I will check out the tablet holder too then. Thanks for the recommendation.

Sent from my SM-N970U using Tapatalk
 
Thank you Liger 1956. I like your clip design. Printed a few for my new Anafi. They are lightweight, fit well and seem to provide reinforcement and support for the top of the legs. I also printed some of the other designs at thingiverse and didn't like they way they fit.
 

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