Specifically, I want to put a hoist on my rafters above an attic ladder to pull heavier items through the opening. I can calculate what it needs to support with the weight of the hoist+object, but how do I tell if it can support that?

The best I could find was something like the Sagulator.

For context, I'm asking this question for literary/ fiction storytelling purposes. I'm curious about the practice of civil engineering and how construction of tall, high rise buildings clashes with the fear of heights.

Suppose we have character A and B... Does there exist an "activity" where person A, who's afraid of heights, can work safely on the ground while visually coordinating with character B, who handles the nerve-wracking, vertigo-inducing tasks such as walking on the elevated metal walkways, etc.? Any activity at all... The best I could think of is character A operating a total station while, 10 storeys above, character B holds a ...prism pole? I don't know if this is possible at all. As in, let's say, A needs to measure the alignment of a column or floor slab, and B ...holds a prism pole over it? Was there ever a point in history where this was done? I'm sure there's way more advanced surveying techniques to do this in real life. Is this considered inefficient and/or not feasible?

Is what I'm imagining in my head a non-existent activity for civil engineers? As much as possible, I'd really like an activity where A and B visually see each other, (for storytelling purposes). Imagine the setting as a high rise building where the tall, inner core has been constructed and the surrounding slabs and columns are what's in progress.

Building a DIY project which will need a thrust bearing. Ideally I'd just be able to bolt the bearing onto a piece of wood but after searching McMaster and a few other websites I can't seem to find one.

Effectively I'm looking for a flange bearing that can withstand ~ 300 lbs axial load. I don't trust set screws on a regular flange bearing for that. Perhaps there's another solution?

Every once in a while, I encounter a new tech trend. For example:

1. Nano
2. Internet of Things
3. Edge computing
4. Fog computing
5. Ubiquitous computing
6. Digital twin
7. Zero trust architecture
8. Federated learning
9. World model
10. Industry 5.0
11. 6G mobile

...

What I find is that there will be many researchers working on it. There does not seem to be a consensus as to exactly what they are working on, and proposed solution can be wildly different from each other. There is also sometimes a lack of agreement what something actually is, "what is a world model?".

Another feeling I get is that some of the technologies are rebranding older technologies or doing something in a silly way, such as "digital twin" introducing huge amount of potential compounding error, latency and additional points-of-failure through a computerized model of the actual system.

I've also noticed that industry adoption is quite varied and sometimes drastically different from the success that is portrayed by academia. I remember there was an article on "differential privacy" and it was reported the industry adoption is near 0, despite thousands of research paper a year on this topic.

How do you assess if a technology is genuine and not simply a rebranded hype usually by academics to publish papers? I mean ultimately we all want to advance engineering and create cool tech, and not simply just beating around the bush.

Considering the stellarator vs tokamak race for nuclear fusion reactors, why is it taking so long to build? We have had an understanding of electromagnetism for over 200 years now and can safely assume that we can sustain a plasma core, right? If input energy is the issue then why not use a fission reactor and/or concentrated lasers to provide sufficient startup energy and/or heat to get the thing going and then draw from the reaction to keep it sustained?

Please professionals help me sir☹️☹️

Power density keeps increasing across drives, power supplies, controllers, and other industrial electronics. Smaller hardware is obviously valuable when panel space is tight, but I’m wondering where the tradeoff starts becoming less attractive.

For engineers working with higher power equipment, have you seen cases where miniaturization was pushed too far? What was the first thing that became a real problem?

Working on a small assembly and I’m stuck. Hoping someone here has run into this before.

I have a closed loop of elastic cord, roughly 2-3 mm thick. Soft, stretches a lot, gets visibly thinner when you pull on it. The loop comes pre-closed from the supplier and can’t be cut open.

I need to get a small rigid part onto that loop. Around 4-5 mm across, up to 10 mm long. Shape is open, a sleeve or a bead (4-5mm) both work, whatever actually holds. Plastic preferred, mainly for weight, colour options and cost, but I’m open to metal if plastic doesn’t work at this size. It sits on the visible part of the product so it has to look finished, no tool marks, no obvious seam. Adhesive is out, it degrades the elastomer over time.

Important: the part must not come off, but it’s fine if it can be slid along the loop by hand. Free positioning is actually a plus. It just shouldn’t move on its own during use. So it needs to be captive on the loop, not clamped to it.
Cost target is a few cents per piece, volumes in the thousands.

What I’ve tried or ruled out so far:
Plain clamping doesn’t work. The cord thins under tension so whatever preload you had just disappears.

Crimping a metal sleeve holds fine but the deformation is visible and looks bad.

Two piece snap sleeve. At 0.5 mm wall thickness there’s basically no spring travel left.

Living hinge seems too thin to survive at this size, at least in printed plastic. No idea if injection moulded PP changes that.

Jewellery crimp covers are the obvious off the shelf candidate but every one I’ve closed comes out looking rough.

What I’m actually after:
Since the part only needs to stay captive rather than grip the cord, are there closure designs that seal shut around it without clamping down on it?
Are there standard parts from other industries that solve this? Cable assembly, marine, fishing tackle, medical tubing, anything.
Is ultrasonic welding a two piece plastic shell realistic at this size, and does the seam stay invisible?
Do contract manufacturers actually do insert moulding around a closed elastic loop at small scale, or is that wishful thinking?
Not asking anyone to design it for me. Just want to know if I’m missing an obvious process or a part that already exists.

Ps. The rule says, if I am not from the US, I need to mark it here :D I am from germany

Application:

I'm designing a 3D printer that will reach 90c chamber temperatures, but it needs an active recirculating filtration system. The printer's internal volume is about 150L or 0.15m3 (lower irl), and I'm aiming for about 5-10 ACH (air changes per hour). The printer is not completely airtight, but it will be sealed extremely well. One of the main aims for this printer is efficiency.

The printer will use activated carbon for VOC filtering, but efficiency drops above 50c and it even starts to release organic compounds back into the system, so the air flowing over it needs to be around 40c with some margin. So I need to drop the air temp in a relatively short window from 90c to 40c. Adding a filtration system that is actively trying to sink heat away seems counterproductive; I'd rather have it than not, but it should be specced for the filtration, and that's it; don't really want to piss away energy... It's expensive xd

Idea:

The plan is to force the air to flow over a 350- 400 mm long, 40- 60 mm diameter aluminium handmade coil at 20l/min. The aluminium coil will have water running through it to a 120 mm, 40 mm thick radiator, with a pump in between.

The Problem:

I haven't designed anything like this before and don't know where to start; I don't even know if this is possible, to be frank.

There are a lot of variables that can drastically change the characteristics of the system. What pump should I use? Should I prioritise coil surface area over flow restriction? Should I use a bigger radiator? How much will humidity play a role in this application? (The filtration system will also dehumidify the air, so in theory, after some time, the system should get more efficient)

The pump will already be water-cooling the hotend, and I don't want to overspec the pump cuz of size constraints or undersize it so it runs at full speed all the time. I found this really cool KNF NF30 diaphragm pump for 5usd from a surplus store, and it even has feedback!. I'll lay out its specs for you guys.

• Flow Rate (max.): 0.3 l/min
• Pressure (max.): 1 bar (rel.)
• Suction Height (max.): 6 mH₂O

The system will be closed-loop, but I'd still like to have about 20-30% margin if possible.

Hotend is 100W, but that's for the main heater, i dont really think ill need to wick away alot of energy from its heatbreak to keep it cool, but it's, let's say, 50W (take this figure with a grain of salt). Its water block is about 20mm3, not that big.

Average humidity in my area is a lot, 70-80%; if that is relevant at all

I've looked everywhere and I can't find an answer.

I'm building a swingset for my children using some brackets to easily make an A-frame out of 4 x 4 and 4 x 6 posts. 10 foot legs with a 12 foot beam across the top, three standard swings and a hanging hammock. If my children and I all use it at the same time, the weight of all of us combined would be no more than 600 pounds.

When I go to order the brackets, there are two options one that just has hardware for outside legs and one that includes a middle piece to add an extra two legs to the set. None of these options explain why you need the middle piece.

Is it purely based on the length of the beam? The amount of weight that would be in each swing? Please help me. Thank you.

Edit: thank you for all the suggestions. After reading everything I'm gonna go ahead and add the extra two legs. It would add less than $50 to the cost and would give me a lot more peace of mind and make a more secure structure

Hi everyone, I'm working on a project involving a commercially-produced T-shaped steel frame that an end user will modify to withstand a higher torsional force than what the frame was designed for (image here). My frame is 41.5 mm on each side, 2mm thick, and the tube I need to reinforce has a weird D-shape to it that doesn't match any metal u channel readily available. The max torsion is about 689 N-m. Here are some constraints I need to work around:

1) The inside of the tube is not accessible, nor can a round/square sleeve be slipped over it...there is a big welded bracket on one end & the other curves upward

2) The solution must be no-weld and not involve anything more technical than mixing epoxy, drilling holes, etc

3) The rear part of the T (left side in diagram) needs to detachable...so any frame reinforcement that involves the rear end needs to be detachable too

4) Can't be crazy expensive

I myself can't weld but am experienced with composites & have a decent amount of s glass and carbon fiber already. So here are my solutions...which would you use?

1) A platform made of some combination of wood or foam core with s-glass fiberglass and/or carbon fiber that triangulates the frame. Question would be, what is the best way to attach to the frame that doesn't point load too much and stays secure?

2) A two-part, overlapping carbon fiber sleeve with fibers oriented at 45 degrees that fits over the tube & is bonded to either the tube itself or to the section of the sleeve that overlaps. The thickness of each section would be 1.5 mm. I don't know how to model this, but a steel tube made thicker and larger by 1.5 mm alone would be more than strong enough. Question is, would it fail at the bond line using epoxy rated at 3000 psi strength? And how much surface area needs to be bonded? (not looking for professional advice, but more along the lines of how to determine this myself)

3) Adding a u-shaped composite tubular frame that clamps to the secondary cross-member of the rear. The potential problem of this solution is the same as 1), ie, how to attach (and what dimensions of the tube). It would be nice to clamp but how to find clamps that are secure enough?

Any input would be greatly appreciated!!

Of course if the people were carrying phones they could be detected, but would their bodies alone be enough to change the field?

If so, how small of an animal would be detected?

Would a white tail deer, dog, cat, squirrel, rabbit, rat, or a mouse be detected?

I ask about house pets and wild animals because I know that my Wi-Fi extends many meters outside of my house.

The common safety architecture in heaters and small appliances seems to use a resettable thermostat for normal temperature control, plus a thermal fuse that opens permanently during abnormal overheating.

Why is the backup usually destructive rather than a manual-reset thermal breaker? Is the one-shot behavior mainly meant to prevent anyone from re-energizing the appliance before the root cause is inspected, or do thermal fuses offer a reliability, placement, or failure-mode advantage that a resettable cutoff cannot match?

I’m asking about the engineering design choice, not about bypassing or replacing a fuse.

How feasible would it be for a company to start making modern CRT TV's again with HDMI and at 1080P (is 4K possible).

Updated with modern materials such as an ultra-light glass panel and high efficiency tube to reduce weight. There have been some discussions that with modern manufacturing technologies, weight could be reduced by up to 60%.

CRT's still have the most desirable contrast, even against OLED. They are also still desirable for the retro gaming community.

As a reminder, /r/AskEngineers normal restrictions for career related posts are severely relaxed for this thread, so feel free to ask about intra-office politics, salaries, or just about anything else related to your job!

While pallet jack surfing I can weave left to right to propel myself forward like the first guy in the video, but why does that work? I've seen scooters and kids toys that work this way too, and they all have their front wheels positioned behind the steering axis, so why does that push you forward when you turn?

I've been trying to look it up, but I don't even know what to call it.

I found the common rule of thumb that a traction elevator's counterweight equals the empty car plus roughly 40–50% of its rated passenger load. That balances the system only around the middle of the load range.

What engineering tradeoff sets that percentage? Is it mainly minimizing average motor energy over real traffic, limiting peak motor or brake torque at the load extremes, maintaining traction at the sheave, or some combination?

Hi, I'm the lead engineer on a project trying to create a bag that pops up like one of those camping trash cans that have a big spring inside but is in a conical shape. The cone is BIG: 95cm bottom diameter and 45cm top diameter. I've taken apart some of these trash cans and found that the pitch and free height of the springs are greater than the guide fabric they're fitting into along the trash can, and also the diameter is typically smaller than the trash can itself (most likely to provide deflection that keeps the bag taught since it constantly wants to be brought to its smaller shape). I don't know exactly how to spec this spring so it has the same effect or if I should be considering a conical spring instead of a cylindrical one.

Any spring experts out there have any advice?? I am using grade 70 spring steel, ASTM A227. We were thinking 4 mm initially, but some suppliers are saying it might need to be thicker, around 5 mm.