r/AskEngineers

I think this is relevant, given that I'm sure a great deal of engineering of various types would be involved, but feel free to remove if it's not.

In this scenario, I'm a billionaire who is building a huge mansion somewhere in the US. I want some trees on my property but I'm too impatient to wait 90+ years for the trees to grow to the height that I want them.

Could I, with enough money, transport fully grown trees from one part of the world to my back yard without killing them in the process? What kinds of things would need to be taken into account to make that happen? Would new technology need to be made, or could one do it with existing technologies?

Cheers in advance!

It's hard and durable but the outside layer is smooth and soft, it's used in some phone cases with rounded edges, and it has a matte finish. It kinda feels like a halfway point between plastic and rubber. Thanks for helping me 🙏

I am doing some back-of-the-envelope calculations for some thermomechanics applications. I came across the following scenario, which gave me an unintuitive answer: A bar of length L and cross-sectional area A, made of a material with Young's modulus E and coefficient of thermal expansion a, is loaded in the normal direction with a force F. The change in length of the bar can then be expressed as:

u = (F * L)/(E * A).

So far so good. However, now heat the bar by some amount T. Intuitively, I would guess that u would increase, or at the very least remain unchanged; however, if thermal expansion is applied to both L and A, this does not seem to be the case:

u = (L * F * (1 + a * T))/(E * A * (1 + a * T)^2)

=> u = (L * F )/(E * A * (1 + a * T)).

This implies to me that the bar becomes stiffer as temperature increases. Is this conclusion correct, or am I overlooking something? I could imagine that E decreases as temperature increases, or something similar. I'd also be grateful for a source on the subject.

Hello.

As the title says. I am looking for energy dampening tape to add to my ice hockey goalie mask. I have 1/8th thick foam with little clearance before my face. looking for a material that I could put underneath the foam. I am concerned that if I choose the wrong martial that it will send the energy inwards towards my head instead of stopping it or dissipating it back into the shell.

Thank you! The large helmet manufacturers use a product similar to what I am asking about but I can’t find exactly what they’re using.

Hello,

I am looking to set up a rainwater irrigation system using two stacked IBC totes connected in series. I can't let the excess overflow water exit the totes because it's too close to the foundation of my house. The tanks are 48"x40"x45" and can hold 1000L each.

The system would have a hose running from it down my fence into my backyard to irrigate 8 8'x4'x2.5' raised garden beds just using gravity to irrigate. I know a time controlled valve would be used for daily irrigation but how would I implement an overflow mechanism? The only thing that comes to mind is a ballcock valve but I wouldn't know how to set it up given the size of the tanks.

The wing loading is about 5x smaller [100kg/m² aerobatic rc / 630kg/m² a320] even on a most stressed category. My guess is it could be possible on a really tight 8G turn but id love to hear other minds.

Basically the title. For those who don't know, OASIS visor: a retinal-display system that projects the virtual environment directly onto the user's retinas rather than using conventional screens. It also handles audio, voice, eye-tracking, and 6DOF input. (Also allows retinal scans for added security)

I've heard of retinal displays being tested and think it'd actually be such a cool technology if someone made it. I'm aware there would likely be health concerns, but how feasible is the idea?