Design Exercise

External options and variations: rear end mods, side vents, doors, cage mods, wings(!), etc.
Midlana1
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Re: Design Exercise

Postby Midlana1 » 14 May 2015, 05:56

Don't forget to place the rear parting line so it passes through the aft down tubes.

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Re: Design Exercise

Postby bgkast » 14 May 2015, 13:29

Looks great! Make a kit that I can drop onto my chassis, in blue if you please. ;)

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Re: Design Exercise

Postby ChrisS » 15 May 2015, 00:47

bgkast wrote:Looks great! Make a kit that I can drop onto my chassis, in blue if you please. ;)


:D was thinking the same Bryan! Making that would be well beyond my skill and patience I think. Limit of my talent there was making some composite wheel arch liners and other odd small parts for my Stratos replica.
Last edited by ChrisS on 16 May 2015, 23:44, edited 1 time in total.

Matt
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Re: Design Exercise

Postby Matt » 16 May 2015, 18:16

freakynami wrote:Wow, that is a lot of work, and I think it is looking really great :)

You asked earlier about the lock clearance at the front wheel, does the front wheel turn within the front guard? (as in, the guard is fixed?)

I like the engine cover area, and the whole nose, wondering if there needs to be some sort of filler for the little open triangle at the bottom of the screen?

Is this still Delftship?


freakynami,
Thanks for the kind words. This version was drawn and rendered in Modo.

I was asking about the wheel clearance as I was considering a fender design that would cover the tire throughout the entire steering swing, ended up wider and visually heavier than I liked. The way it is drawn now, the arch is open on both sides, clearanced so the tire can swing in and out of the fender. Another option would be to slice the fender and have the back portion attach to the upright cycle fender style. There would need to be a sizable gap though between the pieces and also not visually appealing.

Regarding the triangle filler, I still need to work out the dash layout so there may end up being something there.

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Re: Design Exercise

Postby Matt » 16 May 2015, 18:19

Midlana1 wrote:Don't forget to place the rear parting line so it passes through the aft down tubes.


Yes Kurt, the plan will be to have the fender and engine cover meet at the down tube.

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Re: Design Exercise

Postby Matt » 16 May 2015, 18:22

bgkast wrote:Looks great! Make a kit that I can drop onto my chassis, in blue if you please. ;)
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Re: Design Exercise

Postby Midlana1 » 17 May 2015, 09:30

I know why you made the front fenders the way you did, but aesthetically, it looks... backwards. That is, if I cover up the top third of the picture above, the front of the car look like the tail end. Fenders that are aerodynamically shaped are like a teardrop, with the blunt end toward the front and the tapered tail toward the rear, and the render is just the opposite. My tires are only about 8" behind the nose of the car and the tires in the render appear further aft. I think moving them forward would fix the appearance - though I realize it's just a render at this point.

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Re: Design Exercise

Postby John » 19 May 2015, 20:36

If you look at the image used to derive the side view the front wheels are turned which may have put the front wheel aft of its true position. Also the nose appears to be longer that Midlana's. Peoples natural perception of what is aerodynamic I find to be normally backwards compared to reality i.e. sharp at the front and blunt at the rear. Objects designed to cut through thick mediums are this way around. Midlana in general fits that wedge shaped profile. Packaging requirements dictate it. The design has very little overhang at the back and so must be blunt at the rear of the car. The car fendered as rendered would be not be less aerodynamic than one with cycle guards or open wheels. The only real draw back in aero terms would be a little unnecessary wetted area at the front of the fender. The front of an aero shape can be blunt or sharp it makes little difference (but blunt is better) but the departure angles at the rear of the shape must be shallow or the boundary layer will stall and the flow will unstick from the shape. I don't believe the OP is trying to create an aero body though the extent of the bodywork does present an opportunity to improve aerodynamics.

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Re: Design Exercise

Postby Matt » 20 May 2015, 16:01

Midlana1 wrote:I know why you made the front fenders the way you did, but aesthetically, it looks... backwards. That is, if I cover up the top third of the picture above, the front of the car look like the tail end. Fenders that are aerodynamically shaped are like a teardrop, with the blunt end toward the front and the tapered tail toward the rear, and the render is just the opposite. My tires are only about 8" behind the nose of the car and the tires in the render appear further aft. I think moving them forward would fix the appearance - though I realize it's just a render at this point.


Kurt,
I appreciate your comments and opinions. To me one of the best things about the internet is that I am able find someone out there that has done all of the hard work, designed/engineered the car that I was dreaming about, built the prototype and then demonstrated the performance on the track chasing Porsches. And that for a reasonable cost is willing to share his hard work with me so that I can build it (or can try to).

What looks good or right to someone is a very personal thing. These images represent a few things for me and are just the beginning versions of a design that I hope to build. First, this is a rendering of some simple visual modifications to what I think is already a cool "thing". I wasn't going for perfect aero or million dollar looks, only a unique version of something that I already want in my garage. Second, my car will have fenders (and probably a bimini top). I live in Florida and despite what the weatherman says it is likely to rain at any time. The thought of water and road grime being flung up and onto my wife, myself and the interior is not appealing. Third, your design inspired me enough to sit and gain proficiency with the 3d modeling software that I purchased a few years ago and have been struggling to learn. I thought the results were decent and I wanted to share them with the community that you have built.

When I look at the images I have shared, I see a lot of things that I would like to or will change. I understand that the best aerodynamic shapes are round in the front and taper to a thin section in the rear, just like a fish. I can still see in my minds eye a diagram of this concept from a book on Formula One car design my parents bought me as a kid. I have tried another version of the front fenders with a lip/spoiler like the ones on the rear of modern motorcycle helmets (and the rear fenders as drawn) to help break the boundary layer (as John mentions in the next post) away cleanly. This lip will reduce drag and lift but so far I am not ready to show these to the public. Each fender has a "nose" forward. This "nose" was inspired by the styling of today's hypercars like the Laferrari or the Pagani only these cars have complete bodies that allow the rear of the fender to taper allowing the boundary layer to stay attached and to flow into the door. I do think this nose and the wing will provide increased down force at the front which could help the turn-in on this mid-engine design. The choice to have the rear of the front fenders hug the tire was just to keep the visual an actual weight to a minimum. As John mentions below, this design won't be any worse than an open wheel/tire or the traditional cycle fenders.

Regarding the nose, in this latest versions I have drawn the chassis to the book dimensions. The wheels are where you designed them to be. I have extended the nose more than your version only to make room for the front wing. This front arrangement was chosen purely for style and, I believe, will also create a torsion box strong enough to support the fenders and splitter. I have also thought about moving the nose and wing rearward and providing scallops in the wing with clearance for the wheels to turn in to. There is yet another version in my head where the front wing twists up over the tire then down to form a box with the splitter, the rear of the tire will be covered with a separate, suspension mounted cycle fender but as freakynami has stated each of these versions takes a lot of work and I haven't gotten around to them.

With all of this discussion about aerodynamics, modeling software and torsion box strength I have to state, I have never had any official training in engineering, design or 3d modeling.

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Re: Design Exercise

Postby Matt » 20 May 2015, 16:10

John wrote:If you look at the image used to derive the side view the front wheels are turned which may have put the front wheel aft of its true position. Also the nose appears to be longer that Midlana's. Peoples natural perception of what is aerodynamic I find to be normally backwards compared to reality i.e. sharp at the front and blunt at the rear. Objects designed to cut through thick mediums are this way around. Midlana in general fits that wedge shaped profile. Packaging requirements dictate it. The design has very little overhang at the back and so must be blunt at the rear of the car. The car fendered as rendered would be not be less aerodynamic than one with cycle guards or open wheels. The only real draw back in aero terms would be a little unnecessary wetted area at the front of the fender. The front of an aero shape can be blunt or sharp it makes little difference (but blunt is better) but the departure angles at the rear of the shape must be shallow or the boundary layer will stall and the flow will unstick from the shape. I don't believe the OP is trying to create an aero body though the extent of the bodywork does present an opportunity to improve aerodynamics.


John,
Excuse my ignorance but what is "the OP"?


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