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  1. #1

    Attn engineers: mechanical discussion for concept airliner

    this is my second phase. Cutting out doors, laying out dimensions against a accurately scaled human test pilot, laying out general ground work for all the detailed mechanical parts (landing gear, door hinges, interior design, etc)

    If this will be a vertical takeoff (also regular take off and landing) aircraft, the biggest challenge will be later on figuring out the mechanics that are believable in the real world. Half art but half taken seriously.

    a) Do I design the main and rear engines to hydraulically rotate 90 degrees upwards during landing and take off? (like the Osprey military aircraft)? More moving parts
    b) Or do I design air slots into the bottom of the aircraft and leave the engines as are? (like a harrier jet setup) less moving parts
    c) Or do I design it kind of like the osprey where both front and rear engines (including the wings) rotate 90 degrees as one piece?
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  2. #2
    Member SterlingRoth's Avatar
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    Engines look a little heavy for the wings, but those hi-tech alloys are strong. I feel like articulating the engine pods would break the smooth, flowing lines. The additional vents for lift would interfere less with the profile, but you would need to have some kind of high volume throughput from the engines to the vents. Maybe a series of vents on the bottom of the wings?
    The BlenderArtist formerly known as Mexicoxican



  3. #3
    Originally Posted by SterlingRoth View Post
    Engines look a little heavy for the wings, but those hi-tech alloys are strong. I feel like articulating the engine pods would break the smooth, flowing lines. The additional vents for lift would interfere less with the profile, but you would need to have some kind of high volume throughput from the engines to the vents. Maybe a series of vents on the bottom of the wings?

    good point. The more I look at the harrier jet, the more I feel like a series of slotted vents down the bottom length of the wings would make more sense (like you said). Perhaps that in conjunction with some type of airflow "seal" inside the engine pods that redirect thrust from behind the engine into the wings and out of the slots. Same with the backside of the plane. Thank you for throwing some ideas back and forth with me.

    Maybe even a system where the inner half of the wing/elevator are strictly downward force to keep the plane in the air and the outer half dedicated for roll control.


    It's almost like I'm borrowing ideas from the harrier jump jet, the boeing 787 and the boeing c-17 globemaster (especially in the layout of the landing gear).
    Last edited by LRosario; 16-Feb-17 at 13:14.



  4. #4
    going into phase 3 design. a) I have placeholders for the landing gear (about to design detailed tires and mechanics b) cutting out wing flaps and moving parts from wings and elevators c) cutting out and designing details for nose section and fuselage d) shaping out the tail section. Official name of the project is now called "E-Jet. Model: Future 100". Designer: Lee Rosario
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  5. #5
    Even though i am not an engineer... i do see some issues.
    for one, the wings look like they would angle the plane dwnwards.
    Also the aerodynamics is bad, because of the lump in the middle,
    also the wings look flimsy and thin, they wiuld need additional supporting if they were to support high G flight.
    another thing is the size of the plane and its efficiency.
    it has 4 engines that would only transport less than 100 passangers.
    so the fuel efficency would be low.
    also, the 2 engines at the back, they look like they are useless.



  6. #6
    hmm ok. I can see some of your points. I could shape the hump down and streamline it a bit. Im thinking I can thicken the base of the wings more realistically (from the engines inward). Looking at pictures of the 787, the outer half of the wing I think the thickness would work. It seems to thicken quite a bit more at the base. I could look at the angle of attack on the wings...I'm just imagining how they would flex (up and down attitude and roll front and back attitude) to level out in flight.

    The rest I can take a look at. It is a future concept, so I'm trying to imagine what I can get away with in terms of alternative fuels, future engine design improvements in the real world and weight reduction. Thanks for the input.

    Originally Posted by Yusuf Raja View Post
    Even though i am not an engineer... i do see some issues.
    for one, the wings look like they would angle the plane dwnwards.
    Also the aerodynamics is bad, because of the lump in the middle,
    also the wings look flimsy and thin, they wiuld need additional supporting if they were to support high G flight.
    another thing is the size of the plane and its efficiency.
    it has 4 engines that would only transport less than 100 passangers.
    so the fuel efficency would be low.
    also, the 2 engines at the back, they look like they are useless.
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  7. #7
    here are some fixes and things I am still thinking about. Again, half sci-fi concept and half rooted in reality. I don't expect boeing or airbus to work on a vertical take off airliner anytime soon .

    Keep the thoughts flowing.
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  8. #8
    so i decided to take out the rear engines and just rework the tail section and work the design around the oversized engines for the extra vertical lift during takeoff and landing (of course with the option to land normally when needed)
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  9. #9
    Nice plane. Just a few questions though.
    What's the AOA on the wings? They appear leveled in the render.
    Are you going to attach something to support the engines or move them closer to the body?

    You want to have your center of mass below the main wings to reduce stress on the body, fuel tanks in the wings are aligned with the center of mass. Most airliners also have fuel tanks in front and behind the cargo hold so that they can be filled or emptied to correct the center of mass to account for cargo.



  10. #10
    wasn't sure what you mean by engine support? Maybe the angle of the photos didnt show the engine pylons that hold up the engine in place. I'm guessing it should be strong enough to hold the weight? I included a picture of that and the angle of attack on the wings (cross section) and a flat plane to show relative angle. I don't know the exact angle but I can do the math once its shaped out. I figure if that needs to change, or the shape of the wing, i could do that.

    Definitely keeping check on the center of gravity for sure. Figuring out how the theoretical weight distribution would be laid out?


    Originally Posted by GrimZA View Post
    Nice plane. Just a few questions though.
    What's the AOA on the wings? They appear leveled in the render.
    Are you going to attach something to support the engines or move them closer to the body?

    You want to have your center of mass below the main wings to reduce stress on the body, fuel tanks in the wings are aligned with the center of mass. Most airliners also have fuel tanks in front and behind the cargo hold so that they can be filled or emptied to correct the center of mass to account for cargo.



  11. #11
    sorry I forgot to attach the photos
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  12. #12
    Originally Posted by LRosario View Post
    wasn't sure what you mean by engine support? Maybe the angle of the photos didnt show the engine pylons that hold up the engine in place. I'm guessing it should be strong enough to hold the weight? I included a picture of that and the angle of attack on the wings (cross section) and a flat plane to show relative angle. I don't know the exact angle but I can do the math once its shaped out. I figure if that needs to change, or the shape of the wing, i could do that.

    Definitely keeping check on the center of gravity for sure. Figuring out how the theoretical weight distribution would be laid out?
    I mean the distance between the engine and wing base. The wing might snap from the weight.
    The wing is being pulled up due to lift while the engine is being pushed down due to its weight. Think of a pencil, is it easier to break it in the middle or near one of the ends?

    The AOA looks about right.



  13. #13
    I see. Yeah I did thicken the inner base of the wing a bit. I keep coming back to the 787 pictures as a bench mark for where airline manufacturing standards are right now and it seems as time goes on, the things just get thinner and thinner. I'm trying to look at my design with x-ray vision and trying to imagine if there was some kind of extremely strong structure that would run over the top of the fuselage and into the wings. Like a backbone...except it runs left to right. I figure that could take care of the downward motion of the engine weight (assuming I don't just say in the future engines will be much lighter). I could imagine that the negative G forces exerted during flight wouldn't be as stressful on the wing. If this was like a full on project, I would of probably brought it into solid works and tested it.

    Unless blender has strength test simulations I don't know about. I suppose this is where the concept aspect of it comes into play

    Originally Posted by GrimZA View Post
    I mean the distance between the engine and wing base. The wing might snap from the weight.
    The wing is being pulled up due to lift while the engine is being pushed down due to its weight. Think of a pencil, is it easier to break it in the middle or near one of the ends?

    The AOA looks about right.



  14. #14
    phase 3) working on main wing and engine detail (lines in the wings are cut not textured). Then moving back towards the tail section detail.
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  15. #15
    finished the basic outside details, basic paint job and cutting out windows and cargo door. Now finishing outside small details before working on interior and landing gear
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  16. #16
    This is looking real good now you've started adding panel lines, little things like that to break up overly plain expanses and overly curvy bits always improve a model. The design looks like something I could imagine being in use in a few decades.



  17. #17
    Your engines look to sit too far 'ahead' of the wing and too high on the pylon. Engines can suffer a compressor stall due to a high angle of attack. Positioning is critical to reduce this. When an aircraft is in 'level' flight, its not really level. Level just means maintaining the set altitude. An aircraft in flight will always have a slight nose up pitch or positive angle of attack. Thats why the horizonal indicator (HSI) is adjustable to account for this.
    To explain a little more, with the engines out far ahead of the wing, you are inducing strain and stress at the spar anchor points. Metal fatigue would occur and result in premature engine separation that would compromise the entire flight envelope and have potential catastrophic consequences. Not only that, you are increasing drag by having more surface area than necessary. You also run the risk of disrupting the smooth flow of air over the wing which is where the lift comes from. Low airspeed with a high angle of attack can be problematic with engines sitting too far out and too high on the pylon. Now the distance below the wing may just be optical impression based on the image only. In 3d it is easier to tell if its too high. Generally it will still function, just less efficiently. You can mount the engines 15ft from the wing and it will still work. You will be increasing the drag and reducing efficiency and comfort.
    Basically, you should move the engine back a little, and drop it down a few feet. The heat from the exhaust is going to bake your bottom surface and pylon.
    Last edited by kevintampa5; 25-Mar-17 at 03:15.



  18. #18
    Have you thought of adding the types of X like wing tips in use on the latest boeing 737? They might be appropriate to a near future aircraft design, though I don't know enough to say whether they might conflict with other elements of this design's aerodynamics.



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