Projects Introducing the Roofus Special

Flipper,
Just spent my train commute the past couple days reading through this. I am so inspired, as I would also love to build something like this! PLEASE bring this further than just garage art! Heck, if I had the time I would be driving down to help you!! Would love to see this thing come to fruition as I am sure you would too! Best of luck, and thanks for the inspiration!

 

Thanks for the encouragement. I'm currently thinking about trying the Miller IFS again, but with more of a dipped/dropped look. ....almost if the real miller arms were turned upside down. The upper arm would mount under the top frame rail.

 

Wow...killer thread... Look forward to more updates!!!!

 

I have missed this thread but man, this is amazing!! Great fab work, looking forward to see it finished!

 

It looks like my next long weekend to play on the car will be new years weekend. I wasted my long thanksgiving weekend on the beach. ...but it wasn't all bad.


Click on the pics for video


part 2

 

Well, maybe it could be your car's mascot....instead of a greyhound on the hood, you could have a "Kraken" http://en.wikipedia.org/wiki/Kraken

 

I ordered a set of balljoints for the front end. I guess I am going to take a swing at upper control arms after Christmas.

 

Now to try an figure out a Miller-ish upper control arm. These might be the first NEW parts in the car.

 

Here is where I was on the front suspension. I-beam lower control arm parallel to the ground, transverse leaf spring just above that, and jag spindles.

The original plan when I started this build was somewhat parallel upper arm that attaches to the top of the frame rail.

I'm not really feeling it. It takes away from the swoop.
Attaching to the side of the frame helps a little.

The "way out there" alternative is the miller-ish, air-foil idea. Make a swoopy tube a-arm and shroud it in sheetmetal. The idea is to go under/around the frame rail with the upper arm. mounting point would be on the back side of the frame rail, up high. .....squint real hard and you might see it.

 

The mock-up pieces are just there to suggest ideas for the upper arms profile. Real arms will have triangulation.
The curved tube idea is based on this cars suspension. The air foil "axle" is really the upper control arm.


My version would be more of a "dropped axle" and would be made of steel instead of cast aluminum.
This car has the same style suspension on both ends (IFS, IRS and FWD in 1935!)

 

Since your asking , I would be inclined to make the top arm a swoopy narrow A , mounted on the side of the frame so a cover of sorts could follow the arc and line up with the top of the frame . Besides transverse strength it would also allow you to add a threaded section for some geometry adjustment .

Keep at it ... And who knows , you might end up with one hell of a fun track day car !

 

I would mount it on the outside of the framerail.that way the arms will differ most in lenght. Mounting on the backside will make them almost equal lenghts (it looks that way )

 

Hey Flipper,
Glad to see you're still innovating on this one.... As much as I like the "single" arm look of the Miller, I'd look carefully at wheel motion as the suspension cycles. The Miller looks like a true parallel link setup, which would be tough with the height of your Jag spindles. Keep in mind that it's not the arm itself, only the pivot points, that make the effective "angle" of the arm.

Your sweeping curve shape would look really cool, but may not give the wheel motion you'd like with the pivot way down low like your mockup.

Keep up the good work.

 

Love this build. Inspirational.

 

How about doing the upper arms as aerofoil elements, with the lower arms as more delicate arrangements of links? The uppers are closer to the wheel axis, and can be designed to "grow" out of the frame rails. The only thing is that it is usually the lower arms that are involved in springing and damping, but this is not necessarily so. Transverse quarter-elliptics inside the upper arms?

 

I started the morning by swapping in the new balljoints.





gotta cut the bolts down.



supporting the weight under the spindle shows what the extra leverage does to the spring rate. I gotta add some leaves back to the pack. The tire is going to be even farther outboard.



I shimmed the ride height back up and bolted the hub on to get a more realistic picture of the a-arm's environment

 

I was having a hard time explaining to dad what I wanted to do, so I broke out the posterboard.





it needs a ball joint pocket




slimmer pocket , more front to back shape

 

I'll play with that idea this afternoon.

 

Yeah, they would be close to equal length. I know I wouldn't be getting any camber gain in turns with this set-up, but I figured it wouldn't be much different than a straight axle.

 

And pictures of my future tail lights (5" tractor headlights?). Paint the inside of the lens candy red and load it up with leds from a tractor-trailer tail light.

 

The problem with anything other than parallel equal length arms will be geometry. With unequal length arms the camber changes when the wheel moves up and down. How much and in which direction is affected by the angle and length of the upper arm. I don't know enough to tell you what it needs to be, only that it changes. There may be some good unequal length arm front suspension texts/illustrations on the 'net, time for you to search! Otherwise you'll end up like I did when making new steering arms for my rack and pinion conversion on my Rambler -- with something that won't work the first time! Had to read up on Ackerman angle and do some figuring to make steering arms that worked.

Your dropped tubular axle idea may be your best bet. Would certainly be the easiest to set up. Bend the tube then weld on brackets to take the Jag spindles. From the looks of the upper ball joints could be mounted with the bolts perpendicular to the frame. The bracket could be made to lean the tire in at the top so spacers could be used to lean it out as necessary to get the desired camber angle.

 

Those will be nice big tail lights, which is good!

 

It looks like I'm holding a **** in this picture. ....One that is exactly the right size.

 

Shape too, and it's firm! ;>

 

Here's a site that will give you enough information on suspension design to get a start on the engineering you'll need. There's a lot more information out there to keep you busy for a long time.

http://www.rqriley.com/suspensn.htm

 

Flipper - please disregard my last comment. The photographs cast a lot of light on the design. I like what you've got in mind with the lower arm shrouding. I'd be inclined to let the spindle be exposed, though.

With a solid axle, camber remains constant relative to the road, barring tyre compression and such. With equal and parallel control arms camber remains constant relative to the frame (as it does with trailing arms, for instance, and sliding pillars) which means that you gain positive caster equal to the roll angle in turns.

If the arms are unequal length and parallel at ride height, the tendency would be to gain negative camber in both bump and droop, which will counteract positive camber gain due to roll - but only partly, unless the geometry is really radical. You'll find that such radical geometry will only work over a very short suspension travel.

I cannot think of a production-car ifs that does not gain net positive camber in roll. This is not only cars designed for "safe" gross understeer, but cars with a reputation for good handling, too. Hence my conviction that solid axles, located with due sophistication, are worth another look.

Arms can be equal length if they converge towards the centre of the car. As long as the arms aren't parallel the spindle would rotate about an instant centre located at the arms' intersection, so camber wouldn't be constant. The net camber gain would still probably be positive, as the effective arm length would likely be more than half the track, if swing-axle effects like jacking are to be avoided.

 

I couldn't make myself pull the trigger on an arm design yesterday. The drastic sweep up to connect to the ball joint (with room for the spindle to rotate) is what bothers me.

I'm thinking that raising the car a couple of inches would greatly simplify what is required from the upper arm. I'm going to put all of the leaves in the spring and see if that raises it up past where it was supposed to sit....if not, that is a whole new problem.

I guess there is a reason most folks play "in the box".

 

Flipper, This might be a dump guestion, But isn't the miller front wheel drive? And if so isn't that a cv joint and axle? It also appears that it doesn't have an upper and lower control arm, but a common pivot point for the cv axle and joints. I love what you are building and hope you finish it to ride the hell out of it!!!!!

Doug

 

Scew it. I'l just use bailing wire!


I put the spring pack back to what I thought was stock only to find one more leaf afterwards (the one just above the clamps)


It did raise it up.


...still not sure what the upper arm is going to look like.

 

Is that lower arm made with unistrut?