Painting the Frame

Posted by jjludemann on November 18, 2014

Painted frame, back in the lab

As you’ve probably figured out from looking at some of the photos below, I’ve painted the frame. I used Jotun Penguard 2-part epoxy right over bare metal after cleaning the metal with wire brushes and acetone. It took a few days as I had to let it cure before turning it, and all four sides had to be painted in turn in order to get every spot. No magic here, just lots of elbow grease.

: Clean the frame. Cleeeeeeaaaaan the frame.

: Painting the bottom first

: Ready to paint the top

: Top painted

: Painting one side

Welding on More Random Jingly Bits

Posted by jjludemann on November 16, 2014

Some shiny frame porn for you…

I had not realized how many small brackets and things need to be fabricated and welded onto the frame before it can be painted. Weeks of work…

The nose mounts are so strong because the car will be lifted by a nose jack under the wing in the pits.

: Bending nose mounts

: How to bend a small box corner

: Nose mount before welding

: Finished set of 4 nose mounts

: Laser cut aluminum and steel sheet parts ready to go to bender

: Radiator mounting

: Bending an oil cooler mount

: Oil cooler in place

: Shoulder belt mounts and firewall reinforcement

: Pedal cluster mounts

: Fuel pump mounts

: Rear head restraint

: Head restraint doubles as body support

: Driver’s leg protection from steering column collapse assembly

: Anti-submarine belt mounts

: Anti-sub belt mounts in place under seat bottom

: Lap belt mounts

: Floor and diffuser mounts

: Bracket for chain tensioner

: Clutch master cylinder reservoir mount

: Brake master cylinder mounts, front & rear brakes

: Dashboard mounts

: This is how long I’ve been waiting to do a big project– copyright 1990

Redesigning Suspension Components

Posted by jjludemann on April 14, 2012

So I was ready to build the suspension attachment points and decided I’d better do a finite -element analysis. It turns out they needed a lot of tweaking, and in a shin-bone’s-connected-to-the-thigh-bone kind of way, I ended up redesigning just about every suspension part all the way to the lug nuts. Part of this came when the quote on building the upper suspension attachment clevises came in way higher than expected, so I redesigned them so they could be laser-cut, hopefully much cheaper than CNC machining. Don’t have the new quote yet.

Also, I received the huge shipment of parts, supplies, and tools that I’ve been aggregating in LA for almost the past two years, and some idiot in purchasing (me) managed to order the wrong brake calipers. Everything was right except for the mounts, which are the lug style instead of the radial style. At least now I really know the tradeoffs between the two approaches. The upright for lug mount brake calipers is only about 35 grams heavier than the one for radials, and the calipers are $80 cheaper each. Over $1000/pound for that weight savings… Actually, that’s not quite fair as I don’t know the relative weights of the two caliper styles.

Anyway, we have lots of pictures of FEA meshes and results:

: FEA mesh for lower suspension clevis, attachment point for all four lower control arms

: Finite-element analysis results for lower suspension clevis

: FEA plot for front upper suspension attachment bracket that will be welded to the chassis.

: FEA plot for one half of the laser-cut upper front suspension attachment clevis

: FEA plot of one half of the upper rear suspension attachment bracket

: Detail of the FEA mesh for buckling analysis of left front lower A-Arm

: FEA buckling plot for left front lower A-Arm under braking load

: Detail of the FEA mesh for static analysis of left front lower A-Arm

: FEA plot of left front lower control arm under 1600 pounds braking force

: FEA plot for left front lower control arm under 1600 pound right-hand cornering load

: FEA plot of left front lower control arm under 1280-pound left-hand cornering load

: FEA mesh for front axle static cornering analysis

: FEA plot of front axle under cornering load

: FEA mesh for front axle static braking analysis

: FEA plot of front axle under braking load

: FEA mesh for front/rear steering arm

: FEA plot for front/rear steering arm under maximum cornering load

: FEA mesh for front upper control arm attachment bracket, to be welded to chassis

: FEA plot of front upper suspension attachment bracket

: FEA mesh for left front suspension upright static braking analysis

: FEA plot of left front suspension upright under braking load

: FEA mesh for left front suspension upright static cornering analysis

: FEA plot of left front suspension upright under maximum cornering load

: FEA mesh detail of left front suspension upright for snap-ring analysis

: FEA plot of left front suspension upright snap ring slot under cornering load

Building the Cockpit

Posted by jjludemann on February 7, 2012

Time for a photo update showing how I built the cockpit, tube by tube.

: A complete set of tube drawings for one forumula 1000 cockpit. It’s a lot of work to generate these drawings, but it saves a lot of time in fabrication, and ensures the frame is accurate

: Test fitting the tubes for the cockpit floor

: Now we can see the main roll hoop was fabricated too narrow. The holes on the jigs don’t line up properly with the roll hoop

: Found the hidden stash of angle grinder shields removed by my Thai workers. In Thailand, workers just laugh at safety measures. I’ve even had one quit when I insisted he wear eye protection.

: Main roll hoop cut and bent to proper size. Sigh…

: Test fitting the revised roll hoop

: A new bottom member was fabricated for the main roll hoop

: Tack welding the revised main roll hoop

: Once again test fitting the main roll hoop

: Main roll hoop fully welded. Looks much better.

: Four outside cockpit frame rails in place

: Left side vertical tube in place

: Left front lower diagonal in place

: Left front middle horizontal and upper diagonal tubes in place

: Right side vertical in place

: Right front lower diagonal and middle horizontal tubes in place

: Left rear lower diagonal tube in place

: Right rear lower diagonal tube in place

: Two rear middle horizontal tubes in place

: Main roll hoop brace extensions in place. These are required by SCCA rules to be a minimum of 1″ diameter and 2 mm thickness.

: Two upper rear diagonal tubes in place

: Daughter Senna (yes, that’s her real name) tries out the driving position, reports that it “needs work.”

Building the Chassis Nose

Posted by jjludemann on December 29, 2011

Starting the nose tubes.

Test fitting the A, C, & D bulkhead side and bottom tubes.

Adjusting the jigs to fit as I go. Have to make sure they can be removed after welding.

Test fitting the C to D bulkhead top tubes

Top tube: seam on inside of bend. Bottom tube: seam 45 degrees from inside of bend. Note slight rippling on upper tube. This is why seams must not be located on a major axis of bends.

Front roll hoop ready for welding.

Front roll hoop fully welded.

Welds are getting better. Now as long as I don't have to stand on my head I can make a pretty good weld.

Front roll hoop in place. This required cutting the top tube frames. Not a problem as each piece will retain the correct shape.

A to C bulkheads welded. There is no B bulkhead (:-).

A to C to D bulkheads welded

Front roll hoop welded, top diagonals added.

D to E side diagonals added.

The basic frame of the nose from the tip to the front roll hoop, finished.

Building the Front Keel

Posted by jjludemann on December 4, 2011

To get optimal suspension geometry and aerodynamics I’ve designed the car with a front keel under a raised nose. This gives the longest possible lower front A-arms, minimizing the angle changes of the front suspension as it goes through bump and jounce motions. The raised nose clear airflow around the front wing. My computational fluid dynamics (CFD) studies show airflow around the front wing is extremely important as the wing operates in ground effect and generates downforce all out of proportion to its size. I spent a considerable amount of time trying to increase the downforce generated by the underbody and rear wing to match that of the front wing, even though those elements are far larger.

The front keel will use a stressed skin of aluminum formed to shape and riveted to tabs welded onto the frame tubes. This is the highest-stress area of the entire chassis, as under braking something like 2800 pounds of force will be transmitted through these members. You can visualize the car supported vertically on the front keel, with two more cars stacked on top of it, so this needs to be really strong.

Front keel tube is drilled on the milling machine for front lower A-arm attachment points. This will give perfect mounting locations.

Lower front A-arm attachment points were cut and drilled on the lathe, then tapped.

Chassis table comes in handy again for welding the lower front A-arm attachment points into the front keel tube.

Completed front keel tube assembly. Front lower A-arm attachment points welded in place, ends of keel tube capped for strength.

Front keel tube assembly rigidly located in place on chassis table.

The 3-roller tube bender generates about 65 cm of scrap at each end on small-radius bends before it starts generating the correct constant -radius bend.

First front keel down-tube in place. The surface of the keel will be concave to let air flow better across the upper surface of the front wing, necessitating curved tubes to hold the keel.

More front keel down-tubes. The two rear tubes are a recent addition to the design as this area needs to be phenomenally strong and the tubes weigh almost nothing.

Finished front keel and front subframe

The Build Begins– The Front Subframe

Posted by jjludemann on December 4, 2011

After more than a year and a half of design and several months of tool preparation, that long-awaited day has finally arrived: the day I touch saw to metal on an actual car part. The first step is to build the front subframe that sell sit horizontally at the bottom of the nose of the car. The chassis table already has holes drilled and tapped for 3/8″ bolts locating the subframe members precisely. Here’s the first tube in place among the pins on the chassis table.

First tube in place on the chassis table, bent to fit pins

Lower front frame member cut to fit and tack welded in place

Finished front subframe, fully welded. Since it's laterally symmetrical, it's flipped over to weld the bottom.

Front subframe raised to final position, supported by chassis jigs. Note Natural-Polymer Swing Press at right. A useful tool.

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Formula 1000 Race Car Blog

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