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  2. GBH

    What Makes A Ship Move?

    DrD One feature of a marine engineer's training is the constant interaction between forms of energy. I came ashore to work in aircraft stability, nuclear controls, water and wastewater, then moving bridges. Much of the time I called myself a systems engineer. Then I went into dispute resolution - even more fun. I think an engineer needs a catholic mentality.
  3. Hello, iam analysing failure of coupling shaft. Iam exactly not able to make out whether it is a failure due to overheating, loss of lubricant or when my tail rotor hit the ground resultantly its impact load caused it. However, i didnot think it is due to sudden impact load. One more thing if OEM is recommending G355 grease in that coupling and iam using G353, Does it affects or not. Picture of failed coupling is attached. This is the other end. Here you can see teeths of coupling are damaged/wear in a specific regular pattern. Only area of approx 5mm is damaged in this coupling and on the other end splines teeths are of 5mm approx length. This drive shaft has allowed play of 5mm in axial direction
  4. Yesterday
  5. Hi everyone, I faced this problem in an old book (Hall Allen S., Theory and Problems of Machine Design; 1961) the answer is according to the book 592 [in.lb] but I think the bending moment should be 0 because there is no constraints. Could anybody help me to understand this? (the photo is attached)
  6. If you want to model a car just watch this tutorial video you will be guided step by step: Here It is: https://www.youtube.com/watch?v=Li1cwduw9gQ&list=PLj8DSQXVxoQUunBVZ6k9tHMhByNb88Rqh
  7. I make a simple and useful metal bender at home. Do you want to get one. Just watch tutorial video you can make one easily by yourself Watch tutorial video here: https://www.youtube.com/watch?v=AM6dmokmBNc
  8. It's so cool Your metal bender is goo. I made one here:
  9. Last week
  10. DrD

    What Makes A Ship Move?

    GBH, that is certainly a valid point of view. This article was originally written when I was employed by the US Navy in an electric propulsion research group. I was surrounded by electrical engineers who knew a little bit about electric motors and a whole lot about motor controls. But they had no clue at all as to how that made the ship move. In retrospect, I think the key element that they missed was the interaction at the thrust bearing. They saw no connection between the shaft/propeller rotation and pushing the boat through the water. I was trying to close the loop for them. To suggest a pump turned inside out would have simply blow our all their electrons. DrD
  11. GBH

    What Makes A Ship Move?

    As a one time ship's engineer, may I ask if colleagues have considered the proposition that a ship is, in effect. a pump inside-out?
  12. As Christian says above, strainers and filters are basically the same thing. Simply stated, a strainer is also a filter; however, it uses a perforated plate or screen mesh to remove larger particles from a process stream. The major advantage of a Strainer is that it is reusable. There are many different types of strainers, including Y-strainers, basket strainers and duplex strainers. You can find strainers in almost every industry: chemical, food, water, petroleum etc
  13. Though both words are frequently interchanged, strictly speaking, a strainer(also called sieve) physically screens finer particles from more coarse ones by size-screenibg solid particles from fluid(gas or liquid) while a filter physically or chemically separates a desired substance from its mixture irrespective of their phases by means of membranes and absorbents
  14. Hello! I am working on a project to see how workplaces should better enable engineers during COVID. I would really appreciate your insights, the survey is pasted below. COVID-19 Engineer Adaptability Survey
  15. I am wondering the difference between the two. Is there something I am missing?
  16. https://www.growmechanical.com/2020/06/the-ultimate-guide-to-mechanical-seal-part-1.html Mechanical seal Mechanical seal is a mechanical device which is used to prevent the (leakage) liquid coming from inside casing to outside though between static and rotating parts. Mechanical seals are used in centrifugal pumps. There are many types of mechanical seals used in the many equipment’s. It is classified on the basis of design, working, and arrangement. The Seal face is the most important part of the seal. Because the face material is the most expensive part of the seal and that creates a seal between static and a rotating part of the equipment. The description of types of the mechanical seal below. Types of seal
  17. Earlier
  18. Troubleshooting of centrifugal pump There are many types of problems happens with a centrifugal pump that is mentioned below. Flow not develop or low flow Low pressure and low head Power consumption is high High noise in pump Guide to troubleshoot of centrifugal pump mention below, and we will take a view and try to troubleshoot of centrifugal pump. Flow not developed or low flow
  19. This shows How to make a metal bender for artist metal: https://www.youtube.com/watch?v=F0yJohdG_GY
  20. Your numbers disappeared from the problem statement. Please try to fill them in. DrD
  21. As far as the horizontal positioning goes, I think esthetics is probably the main concern. I would suggest supports about 12 inches from each end, but then I'd also make a scale drawing and see if it looks right to you. The bigger question is the vertical support point. You need to look the wall supporting the bottom end of the leg and see where it can best take the loads. Remember that there will be both vertical and horizontal components of the load against the wall. DrD
  22. First, some background. I own an 84 Chevy S10 with a 2.8l V6. I've been fighting the stupid Verajet II carb since the day I bought it. It's been fairly reliable, but the power was always awful, it idled terribly, and didn't get nearly the gas mileage that I think a 1900lb vehicle should get, regardless the style of induction. Now, I am a fairly capable mechanic, and as such, I was not content to simply let this continue. No sir'ee, I had to fix it, so I went to my carb box, selected a suitable carb, (an autolite 2150 seemed appropriate) and proceeded to tear that Verajet off in a hurry. Much to my dismay, the Verajet has a very unique bolt pattern that didnt match any of the carbs in my box. Problem. I needed an adapter, so off to Oreilleys I went, purchased a universal 2bbl adapter, and went to slap it on. No dice. Not a single pattern fit. "Hmm," says I. Looks like I'll have to make one. My MIG welder was out of wire, so steel was not an option, and my TIG welder was loaned out, so aluminum was also not an option. But wait! A wild idea emerged! Sitting right on the spool of my 3d printer, a fresh roll of Shore 95a TPU. Experiment time. Most Chevy's run at about 210 degrees Fahrenheit on the water gauge, or a bit under 100deg Celsius, and my printer will only start effectively melting the TPU at around 230-240deg Celsius, but I knew little about how it would handle that kind of temperature for any period of time, so I took a previously failed print, stuck it on a piece of aluminum foil, and threw it in the oven at 250 degrees F for an hour. Upon removal, the print had held it's shape, and though it was noticeably more rubbery, it did not melt or collapse, and it returned to it's previous consistency as it cooled. This might work! So I set about designing an adapter and printing it. 16 hours later, I have a spacer. As a strength test, I set the new carb on top of the spacer, and the spacer on the floor, and pushed it around. it seemed fine enough, but I wanted to take no chances, so I coated the outside with a few layers of fiberglass resin, and supported the upper bolt plate with a pillar of JBWeld on either side, then siliconed everything to ensure I wouldnt have any vacuum leaks. A few bolts, some cursing, and an improperly utilized cotter pin later, and my truck has been carb swapped! First fire went great. I didnt touch a single adjustment screw and she's purring at a nice, smooth 800rpm. Revs beautifully. NOW HERE'S THE INTERESTING PART: Carb spacers are usually made of something solid and inflexible, like metal, and sometimes hardwood. This one is basically rubber. As the engine revs, the carb will rise almost 1/2 inch above the position in which it sits at idle, stretching the spacer, while still maintaining a seal on both gasket surfaces, thereby increasing intake runner length automatically, and proportional to engine RPM unloaded (its difficult to see when driving as I still have a hood.) Now, my current theory as to why this happens is this: A venturi is essentially a circular wing, and uses the same principle as an airfoil to achieve a different result. In both cases, air is forced to split and travel at different rates to reach the same end point, which forces velocity along the wing edge to increase, and the pressure to decrease. This effect also occurs along the bottom air filter plate on a standard dish filter, which in my case, is bolted to the carb. I think the engine vacuum is drawing the air past the bottom dish FAST ENOUGH TO GENERATE LIFT, and because the carb is mounted on a stretchy plate, it's actually trying to fly! I am currently in the process of designing Spacer/adapter V2, to try to take better advantage of this phenomenon, or really, just see if running an adaptable intake runner length makes any noticible changes in performance. This was quite an exciting discovery, and I'd appreciate your thoughts. I will try to get a video up when I have the daylight.
  23. https://www.growmechanical.com/2020/06/type-of-pump-positive-displacement.html Type of pumps Pumps are used for extract the liquid and transfer one source of liquid to another source. Pumps are uses in many industries like refineries, petrochemicals, oil and gas, pharmaceuticals, power plants, hospitalities and home application etc. It also is very useful mechanical device. On the basis of working and construction pumps classification into many types. On other site
  24. https://www.growmechanical.com/2020/06/type-of-pump-positive-displacement.html
  25. Hi All, I have a question on sealing surface roughness specification as below. A connector with FIP gasket specifies the sealing surface as '4.7/ Ra Max 0.4'. I believe 'Ra max 0.4' is 0.4μm surface roughness spec but what it the 4.7? I've taken a look in EN-ISO 1302:2002 but it doesn't appear to clarify this. Help appreciated.
  26. @The Big B Dude you are an amazing person. Thank you. I was more meaning to light them all with one button without usbs, waterproof. But I will reverse your calculations and find what I need I used this powerbank just for leds before had no problems other than usb getting unplugged from vibration. Maybe I can be a little more optimistic and get like 60 mins life and this power bank? I have fake airpods case I could use for charging and for the button, waterproof it easily.
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