• Welcome to engineeringclicks.com
  • "Thinking outside the box" engineering

    Discussion in 'The main mechanical design forum' started by john12, Dec 9, 2018.

    1. john12

      john12 Well-Known Member EngineeringClicks Expert

      Joined:
      Dec 2018
      Posts:
      373
      Likes Received:
      0
      Hi all,

      I wanted to start a thread to get your favourite examples of unusual engineering solutions where engineers and designers have a solved a problem in a completely different way to the 'standard' way.

      As an example - I have a background in helicopter aviation. Most helicopters have a large main rotor and by spinning this in one direction the main body body of the helicopter wants to spin equally in the opposite direction. This torque force is usually counteracted by a small tail rotor on the rear of the helicopter, and this is by far the most common solution...

      However, there are some other more unusual solutions -
      1. Probably the most recognisable - counteract one rotor with second rotor - as seen in Chinook helicopters.
      2. Use two rotors but mount them along the same axis, one on top of the other. I love this co-axial solution! You see it mainly on a lot of Soviet military helicopters (such as the Kamov Ka-52) but the patent is actually over 150 years old!
      3. NOTAR helicopters use the same principle as a tail rotor - which is to use force on the end of a tail, but this force is generated from exhaust gases from the engine, rather than an actual tail rotor. This is apparently quieter and safer, but an interesting way to look at things.

      Has anyone got any similar sort of examples they'd like to share?
       
    2.  
    3. GoodCat

      GoodCat Well-Known Member EngineeringClicks Expert

      Joined:
      Nov 2018
      Posts:
      96
      Likes Received:
      0
      Modified wing sweep angle. The wing of the aircraft can change its angle of the arrow. In this way, the necessary characteristics are achieved for the heavy samoyots that are capable of flying at a speed close to the speed of fighters. The problem is that a heavy aircraft must have a large wingspan to get off the ground, but this negatively affects its aerodynamic characteristics at supersonic speeds. To raise a heavy aircraft with a sharp swept wing will require incredibly powerful engines and a lot of fuel.

      The solution was a variable wing sweep angle:

      During takeoff and subsonic speed, the aircraft has a wide wing span, like in passenger aircraft, but when switching to supersonic speeds, the wing angle decreases, reducing aerodynamic drag. Unfortunately, this solution has found wide application only for bombers as an example of TU-160 and TU-22. This solution reduces the fuel consumption of the aircraft but in civil aviation for the transport of passengers has not been used because of the high cost.
       
    4. john12

      john12 Well-Known Member EngineeringClicks Expert

      Joined:
      Dec 2018
      Posts:
      373
      Likes Received:
      0
      They also used this in the Tornado Ground Attack/Reconnaissance aircraft that were used by the UK's RAF (and I think Germany and Italy, and elsewhere too). I believe it was known as 'Swing Wing'.

      I remember I had an Airfix model with it in when I was a kid!
       
    5. MSHOfficial

      MSHOfficial Well-Known Member EngineeringClicks Expert

      Joined:
      Nov 2018
      Posts:
      242
      Likes Received:
      0
      When people were discussing wingtip or winglet or sharklet. Boeing came up with raked winglet. That was a very nice solution to all the weight penalty, excessive fuel cost problems that other winglets had.

      So having a normal wingtip gives rise to huge wingtip vortices at the tip of the wing, due to high pressure air leaking from the underside of the wing. These vortices significantly reduce the lift produced by the wings and also create a lot of parasite drag.

      Having a winglet or sharklet reduces the area at the tip thus reducing the vortices. But it increases the weight of the aircraft by increasing a component on the wing, ps the bending moment is higher caused by the winglet usually so the wing spar/web design is affected.

      However, raked winglets are a middle solution for both of these. The weight doesn’t not increase, the vortices do not decrease as much, but its perfect solution for aircrafts like 777 that flight at 0.85 mach and have more focus on transonic drag.

      Also B787 takes the raked winglets one step further with the beautiful curvature. I don’t know its efficiency but the whole airplane is a engineering masterpiece.
       
    6. john12

      john12 Well-Known Member EngineeringClicks Expert

      Joined:
      Dec 2018
      Posts:
      373
      Likes Received:
      0
      Winglets are definitely a great efficiency addition but I was thinking of something even more out of the box, like instead of having a wingtip they made the entire wing into a giant donut so there'd no end to wing for the vortexs to form...
      I'm sure that wouldn't work, but just a really bad example.

      The first thing that got me thinking about it actually was some radio programme in the '90s where a guy was talking about district heating in Soviet Russia. All of the buildings were heated from a large central boiler that served an entire city block, so heating was really cheap.
      He described something called, "a Soviet thermostat"... which was basically just opening a window in winter, rather than somehow turning the heat down. It just got me wondering about completely different ways to approach things as we have in the West.

      There's also a great short story by Harry Turtledove called The Road Not Taken. It's about an alien invasion, but the aliens never discovered certain technologies that we use because they discovered some easier, but more advanced ones, that we accidentally missed. I don't want to spoil it but check it out - https://eyeofmidas.com/scifi/Turtledove_RoadNotTaken.pdf
       
    7. GoodCat

      GoodCat Well-Known Member EngineeringClicks Expert

      Joined:
      Nov 2018
      Posts:
      96
      Likes Received:
      0
      I cannot say that the central heating system, which today operates in the post-Soviet space, is cheaper than individual heating. This has a large amount of heat loss that the consumer pays, besides there are a lot of intermediaries in this system and this greatly increases the cost. The biggest drawback of this system is in the monopoly of the supplier (boiler), which constantly sets excessive prices for 1 Gega calorie heat.

      This system worked in a command economy environment, then it was the simplest solution. Now it’s about 2 times cheaper to heat your home by your own boiler. My friend heats 200 square meters of the house with his own boiler and it costs him about 400$ a year. I pay for the central heating of my apartment (60 square meters); it costs me about 600$ a year. I can not say that in my apartment is warmer than in the house of my frand). I recently stumbled upon a very funny all-terrain vehicle design.

      Big augers are used instead of tracks.

      The all-terrain vehicle all-terrain vehicle ZIL-4904 built in 1972, is the largest in the world. The payload is 2.5 tons. However, he developed a very low speed - 10.1 km / h on the water, 7.3 km / h on the swamp, 4.45 km / h on the raft, 10.5 km / h on the snow. 6dfd068a80.jpg
       
    8. john12

      john12 Well-Known Member EngineeringClicks Expert

      Joined:
      Dec 2018
      Posts:
      373
      Likes Received:
      0
      Ah, it's good to hear some more details about that system from someone who actually uses it. All I know from my visits to Russia and other post-Soviet countries is that it's always very warm inside in winter.
      But then I could say the same about other European countries that experience a 'proper winter' - like Scandinavia and Germany.
      I think we just have bad heating/insulation in the UK because it usually gets quite cold, but not that cold in winter - usually about 0 to 10 degrees, so there's less incentive to have efficient heating! (I'm personally typing this whilst wearing two jumpers, and a hat... inside!).

      That vehicle looks cool! I've actually researched these before because I was once working on the early stages of a project to cross the Bering Strait using one of the these water/land/ice vehicles!
       
    9. MSHOfficial

      MSHOfficial Well-Known Member EngineeringClicks Expert

      Joined:
      Nov 2018
      Posts:
      242
      Likes Received:
      0
      Do you guys know about Abraham Wald?

      During world war 2, Abraham Wald was a mathematician and researcher. And he wanted to figure out how to reduce the loss of planes and crew during battle. He wanted to put extra armor on the airplane like shield plates and skin Doublers. This would ensure the plane would take a shot or 2 more than it was already taking.

      But he did not want to do it for the whole plane because then it would just be heavier and slower, which would make it an easier target during the battle. So he started mapping the airplanes that came back with bullet holes. To find the position where the planes were most hit.

      Everyone said that was a great idea, after you map the gunshots on the airplane and you put extra shielding on those areas and the airplane is fine.

      But Wald had a completely different approach. He said if the airplanes ‘came back’ after being shot at those areas, it means those shots do not destroy the structural integrity of the airplane. So the areas where bullet holes were not appearing on the returning aircrafts, were the ones that needed more shielding.
       
    10. john12

      john12 Well-Known Member EngineeringClicks Expert

      Joined:
      Dec 2018
      Posts:
      373
      Likes Received:
      0
      Yeah, I love this story!

      They basically reinforced all of the areas where there were no bullet holes... because all the planes that got shot in those areas crashed and didn't come home!
       
    11. ramesh

      ramesh Member

      Joined:
      Oct 2018
      Posts:
      23
      Likes Received:
      0
      Thinking different and creating something new is all about engineering.I loved the topic of the thread ..!!
       

    Share This Page

    By using this website you agree to our Cookies usage. We and our partners operate globally and use cookies, including for analytics, personalisation, ads and Newsletters