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 Post subject: Das Boot
PostPosted: October 14, 2014, 7:09 pm 
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Joined: April 15, 2014, 1:54 pm
Posts: 470
I've been requested to put my stuff in another forum so this one looks like a nice quiet little pub where I can sit in the dark at the end of the bar and doodle on napkins. I've got a running tab for a constant supply of Vdubs (double vodkas, not Volkswagens), so I think I'm all set. Moderator advise as necessary.

I'm calling this thing Das Boot since it is similar to the construction of a commercial aluminum boat.

I'm moving on to the upright design as shown on the attached.

I have some friends at the local Maker Place who will hog this thing out of a chunk of aluminum on their CNC mills. I pay for the materials and drop them a nice tip and they say they can make anything my mind can come up with. And they all say, "Um, don't tell my wife I'm getting paid for this, alright? For that, I double their "tip".

More design is needed but at least I know how big this thing has to be. Already there's some ball joint interference but it's fixable. I'm trying to keep the wheel Corvette size because I know a lot of brakes can be crammed inside this wheel. And they fit fat tires.

It's really nice to design your own upright since you can control locations of outer control arm pivot joints. Testing will be mandatory but I can't yet envision myself standing on a 28 ft. length of pipe for the test. I used to use cable tension meters on cranes to verify pick loads and maybe one of these and a stout come-along will be needed.

Bo


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 Post subject: Re: Das Boot
PostPosted: October 15, 2014, 6:33 pm 
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Here’s the latest. I am going to stay with 1/8” aluminum plate. At 180 lbs bare, that includes firewalls, floorboards and a cover over the toes.
For torsional loading, 1/8” rivets spaced at 1” will cover the worst location. After an hour of calculations, I found out a 1/8” rivet is only good for 200 lb(!?). Testing is in order.
I had to draw the perspectives in 2d. I have the perspectives in 3d files but they are structural and don’t plot well.

I’m having trouble figuring out the driver positioning. As I mentioned before, I don’t want to sit on the cold garage floor with a tape measure. I think SAE J1100 covers all standards for humans but I haven’t been able to get a copy.

Regards

Bo


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 Post subject: Re: Das Boot
PostPosted: October 17, 2014, 1:01 pm 
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Joined: December 20, 2011, 10:19 pm
Posts: 198
Hey Bo,

Is there any way that you can flip the lower ball joint over, so you're not trying to pull it apart?

JustDreamin


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 Post subject: Re: Das Boot
PostPosted: October 18, 2014, 5:15 pm 
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That's the way GM ball joints are designed.

I've attached a copy of SAE J1100 that I researched for seating position dimensions. J1100 is interesting but unless you are designing a Locost for your Granma, I don't think it works. In compliance with copyright laws, I enclose this for educational value, not for commercial purposes.

Whoops, file too large to load.

Bo


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 Post subject: Re: Das Boot
PostPosted: October 18, 2014, 7:35 pm 
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The voice of reason
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Joined: January 10, 2008, 4:47 pm
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Location: Massachusetts
Cheapracer posted a nice simple diagram showing the driver and pedals and wheel with dimensions, but I'll be danged if I can find it. I'll look on another computer. It's in the forum somewhere...

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Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.


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 Post subject: Re: Das Boot
PostPosted: October 18, 2014, 11:41 pm 
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Joined: July 29, 2006, 9:10 pm
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Location: Oregon, usually
JustDreamin wrote:
Is there any way that you can flip the lower ball joint over, so you're not trying to pull it apart?
I think that's a good idea (in many ways...it has some problems too; for one thing, it limits the distance between the balls thus increasing the leverage of any suspension loads) but for the life of me I can't think of a single suspension that loads the lower ball joint in compression rather than tension. JustDreamin, do you have an example? Seriously, it could solve a problem I'm dealing with (the flimsy LBJs on Metros).

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 Post subject: Re: Das Boot
PostPosted: October 18, 2014, 11:51 pm 
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Bobber, have you considered using the material or some of the material in the top plate to make rectangular beams on the side of the car instead? Then you have a structure that is very stiff and provides protection for the occupants. The top plate in your pictures looks like it would slice your peoples in half if given a chance...

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Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.


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 Post subject: Re: Das Boot
PostPosted: October 19, 2014, 10:42 am 
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Adding side box beams as you noted would be very desireable - it would add a lot of stiffness. But I have to figure out how much space to leave for the driver/navigator first. And I love fat tires.

I hadn't thought of the possibility of the top plate sliceing the driver in half. Maybe this could be an anti-theft device. Seriously, when I have a workable design ready, I was going to start perforating all the plates with lightening cutouts. Structurally, it would approach a truss made up of rigid rectangular elements. We'll see.

Bo


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 Post subject: Re: Das Boot
PostPosted: January 28, 2015, 2:52 pm 
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Well, I sold the design for Das Boot. The guy used to work for Munson Boat Works up in Seattle and he likes this idea. He knows a lot about welding aluminum so he should be good for it.
My fee? I get the first prototype. If he builds it.


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