3D printing idea

[TheLightSpeedz]

I feel like I'm debating for no reason.

Clearly gimbals and phantoms land feet down, or there wouldn't be any bent or broken gimbals.


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[alirz]

It's the g force that breaks the gimbals, not direct impacts, really. But yes, I wish there was some way to improve their ability to withstand impacts better.

 

[Phantom751874]

I think for the most part gimbal guards are useless.

 

[TheLightSpeedz]

I agree they are useless. But if they were structural they would serve a purpose


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[Wolfiesden]

I give you:

 

[Noble 1]

I think for the most part gimbal guards are useless.

I think they serve their $3 purpose. I've had one hard landing on gravel and I swore I was going to hit the gimbal but the saver did its job.

Soft-->hard landings on uneven ground, rocks Etc... Is there the guard shined.

It's hard to imagine a gimbal saver will "save" the gimbal in a free fall- nothing would. Bubble wrap could tho!




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[henick]

OP doesn't understand physics. We understand you're trying to save the 10$ legs of your phantom and protect the more expensive camera beneath that. In doing so, the gforce could potentially transfer into the body of your aircraft and destroy the phantom on impact --its not the fall, its the sudden stop at the end. Camera might still work when you get a new phantom though but that isn't even likely. A structural engineer could probably provide a better answer if they were to actually work out the numbers behind the tensile strength of the abs plastic used and via some very cryptic equation relate that to the exact amount of downward force that would be required to break it. After a few more calculations with variables like wind speed and temperature of the material considered you might be able to find out that (if the craft is freefalling for more than 12 seconds) at terminal velocity it would take a very small amount of distance to cause the force required to destroy any type of plastic. Never mind the variances for now, (or the unknown drag coefficient) it would probably only handle a 10m drop and likely not even anything close to terminal while using a material as fragile as ABS plastic. Good idea if it was possible to transfer energy somewhere else besides the craft itself. I think the only way to make that possible would be slow the rate of decent to an acceptable value using a MARS platform. There are many threads.

 

[Noble 1]

I thought I did a good job explaining on page 1 but no one even blinked. Apparently my post was invisible. Stress, strain, elasticity, and the frame design are all critical factors. There is no way to protect an air craft from breaking from terminal velocity. You can't save everything without a **** parachute to slow the impact.

In regards to the camera/gimbal and protecting it... the force of the crash WILL 99% of the time eject the gimbal or the camera regardless of where or how the phantom crashes. Its susceptible to the G forces of the crash. As stated, the legs and landing gear are sometimes found in tact and the gimbal is still found detached. Plastic elbows with epoxy or gorrilla glue would definitely make the landing gear more stable. TRIANGLES are known to be the most stable form of support. The issue is the physics behind the crash. IF you make the landing gear indestructible you create an awkward paradox where the weakest point in the crash to absorb the force of crash becomes the body or arms. So you actually CREATE MORE damage to the body than if the landing gear and gimbal were the weak points on impact.

R&D with planes and aircraft have shown that modular designs win in durability and salvage costs. A modular vehicle crashing which has parts seperate during the crash significantly decreases the collateral damage to the rest of the vehicle, as each module falls/breaks off the main vehicle, the force of the crash is subtracted an amount proportional to the mass of the fragment. If the fragment is 25% of the mass of the vehicle then the force of the crash on the body is reduced by 25%. I think this is why there are many carbon fiber gimbal guards and the recommendation is NOT to epoxy them to the landing gear, leave them semi rigid. Purposeful constructive destruction.

 

[TheLightSpeedz]

OP doesn't understand physics. We understand you're trying to save the 10$ legs of your phantom and protect the more expensive camera beneath that. In doing so, the gforce could potentially transfer into the body of your aircraft and destroy the phantom on impact --its not the fall, its the sudden stop at the end. Camera might still work when you get a new phantom though but that isn't even likely. A structural engineer could probably provide a better answer if they were to actually work out the numbers behind the tensile strength of the abs plastic used and via some very cryptic equation relate that to the exact amount of downward force that would be required to break it. After a few more calculations with variables like wind speed and temperature of the material considered you might be able to find out that (if the craft is freefalling for more than 12 seconds) at terminal velocity it would take a very small amount of distance to cause the force required to destroy any type of plastic. Never mind the variances for now, (or the unknown drag coefficient) it would probably only handle a 10m drop and likely not even anything close to terminal while using a material as fragile as ABS plastic. Good idea if it was possible to transfer energy somewhere else besides the craft itself. I think the only way to make that possible would be slow the rate of decent to an acceptable value using a MARS platform. There are many threads.

My point was with a $3 cheap gimbal guard you saved nothing including the money you paid for it. It's always the first thing to pop off the thing.... So why does everyone buy one?

My idea was to build a one piece, gimbal guard, leg platform, that had a absorber built into it.


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[henick]

For short falls or landing on uneven surfaces they're great. Not used for structural integrity and only at sub terminal speed because more structure could tranlate stress to more critical components.

They could build perfect triangles around 3 sides of the gimble if they wanted that but that would add extra weight for a negligible benefit.

Aluminum (much higher tensile strength than abs while remaining lightweight) would be more practical if you wanted to pursue it on your own device.

 

[TheLightSpeedz]

I mentioned that or even carbon fiber. Ultimately the body she'll breaks also.... So if you have a terminal wreck.... Let's say you have to replace the body, legs, props etc. anyway. But if the expensive things are still usable? What IF the camera was usable, the internals and the motors? I think that's possible. I never said I hoped it would just fall and save the day... Obviously it's gonna break... But what's left over.... That's what I think is worth saving.

Obviously you're a smart guy.... Or think you are.... We will never know. But I've already had a company that we all know and love and use a lot contact me for further explanation on the idea to see if they could make something to trial. So I'm not alone.


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[fvader]

I own a Taz 5 3D printer. 3D printed parts are, in general, not as strong as injection molded parts such as the stock landing gear. 3D prints can and do break and separate at the layers. Its just the nature of the beast and how the printers work. You can strengthen the surface of the printed part (assuming ABS) by using acetone vapor smoothing techniques to bond the surface layers more tightly. But you can't do much about internal layers.

3500 lb Epoxy

 

[John Locke]

In the big picture you should not care about the body shell, legs, motors or props. Those are relatively inexpensive, and in a bad crash they will likely all be toast. Those parts cost about $150 and generally speaking they will all need to be replaced, assuming the big ticket items have survived. Those big ticket items include the camera+gimbal, motherboard and the Lightbridge/VPS boards.

I recently had an altercation with a bird, and we both lost. I was above a tree and the bird attacked me. Apparently I was too close to it's nest, I would assume, even though it's not springtime. Hmm. Anyway I ended up losing altitude and clipping the tree after the attack about 50' up and my beloved P3P tumbled down through the limbs (no leaves since it's winter) to a blacktop parking lot below. It wasn't pretty. Fortunately I had a gimbal guard and carbon fiber camera guard installed like this one. My camera and gimbal didn't have a scratch (lucky?). The body, motors and props were ruined. Interestingly enough, both landing gear legs were cracked exactly in the same spot, the same amount. At first the landing gear didn't look damaged at all, I had to closely look to find the 1/2" cracks in each landing leg. They both had to be replaced. The carbon fiber camera guard was intact, not even cracked. The nylon tie wraps were intact also. The gimbal mount bracket had one of the 4 arms snapped ($6 bracket), apparently caused by the G force. I ruined one of the replaceable grey cables because the gimbal bracket snapped (cable = $5). The body shell looked terrible. Two of the motors wouldn't turn, the other two were scratched up. One of the shell motor arms was folded up, and the shell seams were warped. It took an incredible blow to do all this damage.

When I took it apart the motherboard mounts on the top of the battery tray (battery tray = $24) were snapped off (3 of 4 were snapped off) from the impact. These motherboard mounts on the battery tray are really chintzy. I think they were designed that way to break in a crash to save the motherboard, and it worked beautifully. When the boards were tested, everything was good, including the camera and gimbal! I couldn't believe it.

My repair guy charged me $90 for labor (Mike Holt). The P3P and P3A are designed to be quick to fix (a ton easier than my Q500+, OMG). All total it cost $336 to fix the P3P with shipping both ways, took 10 days total including shipping. Not bad at all, considering I was sure it was totaled when I took it apart. I thought it would be too expensive repair. It looked really bad. I was sure the motherboard or the camera would have something wrong with it, so I bought a new P3P, I got it three days after my crash. Little did I expect to have my original craft flying just a week later!

To say the least, I'm a big fan of the Gimbal Guard and Camera Guard setups that are available from several sources. It's good insurance against the craft getting totaled in an accident. Now I have two P3Ps. Got Backup? I do now!

 

[henick]

I mentioned that or even carbon fiber.

Yeah sorry I didn't mean to down your idea. Its a fantastic idea if it was possible. The solution is at best is cost prohibitive unless the speed is drastically reduced prior to impact.

My exposure to free fall math came as a skydiver and we had to learn it well because well, crushed bones suck. Avoiding it has always been the better solution.

A terminal crash can actually be survived just fine via solid construction however the moving parts make it more difficult and shape plays a big part. (gopros are rather invincible).

I'll try to illustrate my thought a little better...
Falling from 30ft would likely be enough to destroy a phantom shell and cosmetics or at least cause serious damage. (agreed?) Let's say triple to be sure of complete destruction.
Maximum speed after ~12s of falling will be ~32ft/s so it will take roughly 1 second to cover that distance by a round object with zero lift.
Even a 100ft vertical drop will only see the average object hit 24ft/s or 75% of terminal velocity. At a 100ft, I'm fairly sure your phantom would still be sub-terminal and still very destroyed.

A rough guess would be it would take a height of about 135ft for a phantom to hit the ground at terminal. I do not hope anybody posts a video confirming this...

I'm sure it may help a bit but that'd be the least of the troubles. A vinyl wrap would probably also help while remaining flexible enough to mitigate some sub terminal damage.

I use a gimble guard also but it is because once I landed on a rock and was sour when it hit my camera. I am interested in mitigating minor damage also.

 

[TheLightSpeedz]

Yeah sorry I didn't mean to down your idea. Its a fantastic idea if it was possible. The solution is at best is cost prohibitive unless the speed is drastically reduced prior to impact.

My exposure to free fall math came as a skydiver and we had to learn it well because well, crushed bones suck. Avoiding it has always been the better solution.

A terminal crash can actually be survived just fine via solid construction however the moving parts make it more difficult and shape plays a big part. (gopros are rather invincible).

I'll try to illustrate my thought a little better...
Falling from 30ft would likely be enough to destroy a phantom shell and cosmetics or at least cause serious damage. (agreed?) Let's say triple to be sure of complete destruction.
Maximum speed after ~12s of falling will be ~32ft/s so it will take roughly 1 second to cover that distance by a round object with zero lift.
Even a 100ft vertical drop will only see the average object hit 24ft/s or 75% of terminal velocity. At a 100ft, I'm fairly sure your phantom would still be sub-terminal and still very destroyed.

A rough guess would be it would take a height of about 135ft for a phantom to hit the ground at terminal. I do not hope anybody posts a video confirming this...

I'm sure it may help a bit but that'd be the least of the troubles. A vinyl wrap would probably also help while remaining flexible enough to mitigate some sub terminal damage.

I use a gimble guard also but it is because once I landed on a rock and was sour when it hit my camera. I am interested in mitigating minor damage also.

Your missing my point by trying to sound smart. You don't know what's possible anymore than I do. If the bird gets destroyed and you can save the critical parts then that's a win.

Anyway, doesn't matter what you say. If and when I get one built I'm sure they will sell like hot cakes to all the dumb people, like myself!




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[henick]

lol. there is lots of snake oil on the internet man. good luck.

 

[Sinisalo]

I agree they are useless. But if they were structural they would serve a purpose


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Something like this?
Gimbal-Guard

These are very thick all carbon fiber, not a carbon fiber and glass fiber combination.