Drawing: Overall Dimensions

Posted by jjludemann on March 10, 2016

Formula 1000 race car top view overall dimensions

I’ve been getting requests for the dimensions of the car from around the world. This should help. Some of the aerodynamic details have changed since this 3D model was made, so don’t take this drawing too literally. If you click on the image above you’ll get a PDF file with both top and side views dimensioned and in high resolution.

Laying Up a Carbon-Fiber Honeycomb Front Impact Attenuator

Posted by jjludemann on August 17, 2015

Nose in place while epoxying aluminum hard points into correct positions

SCCA FB rules require a metallic or composite front impact attenuator. Can’t have cars running around on the track with a battering ram on the front… My impact attenuation structure, or crash box, consists of a carbon-fiber and honeycomb sandwich laid up directly on the inside of the fiberglass nose. The carbon fiber varies from four layers at the front to eight layers around the rear attachment points so that it will crush progressively from the front to the back. Cylindrical aluminum inserts are used in the honeycomb as hard mounting points for the wing to the nose and for the nose to the chassis. This area is designed to be strong enough not just to absorb impacts but to allow lifting the front of the car by the front wing.

: Aluminum mounting points are first epoxied in place with the nose on the frame

: Inside view of gluing the mounting points in place

: Hard mounting points after epoxy has cured

: Cutting the vacuum bag to approximate shape before duct-taping it

: Using template to cut carbon fiber

: Aluminum inserts in side honeycomb pieces create hard points for mounting

: All the layers ready for layup

: Beginning the layup by coating the existing nose with a layer of epoxy

: First piece of carbon fibe goes in.

: A honeycomb and aluminum assembly is inserted on the side

: Ready to draw a vacuum

: Good vacuum after taping over microscopic holes.

: Removing the breather cloth

: Removing the perf ply

: After all vacuum-bagging materials are removed

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

Mounting the Rear Sprocket

Posted by jjludemann on November 15, 2014

Rear sprocket mounted on the differential

The limited-slip differential is a torsen or quaife type made by OBX, imported from the USA for an American-style Honda Civic. The differential ring gear on American Honda Civics is mounted with left-hand threaded bolts, so I blithely go down to the auto recycler here in Thailand and buy a differential for donor parts. Hmmmm… these bolts don’t fit. So I check carefully and find these differentials are sold in Thailand with right-hand threads! I go back to the auto recycler and ask for left-hand threaded bolts. They just look at me with that “crazy foreigner” look. OK, all we have to do is order some American-style bolts from Ebay US… There is exactly one listing on all of Ebay, and they don’t ship to Thailand! Plan B: drill the suckers out and use through-bolts.

This is where I find out the differential housing is made of some ultra-hard tool steel, or maybe kryptonite or something. Wow, are these holes difficult to drill out. Solid carbide end mill, highest speed on the milling machine, lots of lubrication, and wait. And wait. And wait…

Next we had to drill a matching hole pattern in the rear sprocket, then cut it in two halves for quick changing at the track. This sprocket will be for static test only as the new hole pattern wasn’t compatible with the old one, leaving thin aluminum in some places. I’ve since ordered a blank rear sprocket from England which I will cut with only the correct holes.

: Drilling out the ring-gear mounting holes

: Drilling the diff mounting-hole pattern in the rear sprocket on the rotary table

: Cutting the rear sprocket in half for quick changes at the race track

Building the Frame: Roll Hoop to Tail

Posted by jjludemann on March 8, 2012

: Removed the chassis from the jigs for the first time. Welded the bottoms of all the joints, which brought the chassis back to true & flat

: It’s a commuter car! You can carry it like a briefcase.

: Test fitting the rear beltline tubes. Chassis table has pins to locate these tubes, too.

: Rear subframe beltline welded…

: And into place.

: First parts back from the machinists’. Rear keel jig and the keel itself. Beautiful and accurate! Thanks, Somkuan!

: Rear keel, ready for welding.

: …and welded.

: Welded rear keel jig. Really starting to get the hang of this welding stuff. Yay!

: Bottom perimeter of the engine compartment fabbed and welded.

: Finished rear keel and rear keel jig.

: Engine compartment left side lower tubes

: Engine compartment right lower diagonal

: Bulkhead H right vertical lower tube

: Another example of how my Solidworks fishmouthed tubes fit, this one at the front end of the rear keel.

: Lower diagonal tubes holding the front of the rear keel.

: H-J inner upper diagonal tubes securing the front of the rear keel.

: H-J bottom perimeter tubes in place. These 3 tubes were welded flat on the table then lifted into place. Here you see the bottom of the car start to curve upward to clear the diffuser.

: H-J side diagonals. Here we work our way from front to back to avoid cutting off the ends of the tubes to fit them in from the side.

: J left and right lower verticals

: J to L left and right lower diagonals

: Released from the chassis table again to weld the bottom of all the joints. It’s so much easier this way I don’t even try to weld upside-down anymore.

: J-K inner bottom diagonals hold the rear of the rear keel

: K-L diagonals secure the rear of the rear keel to the beltline. This is the back end of the frame.

: Top frame rails from the main roll hoop to the back of the car are finally in place. Now we can see the complete outline of the frame.

: G-H upper diagonals are curved outwards to allow us to remove the engine from the top. The curve must be in the correct plane.

: From this angle you can see the curve. Removing the engine from the top is a design change based on feedback from the ApexSpeed.com forum. Top rail will be made removable later.

: H bulkhead, upper left vertical. Note that it’s not really vertical, but leans forward and inward.

: Test fitting the G-J upper diagonals. Sometimes it’s necessary to fit a bunch of tubes before welding any in place.

: Now we start welding them in place from front to rear. These are the G-H upper diagonals.

: H, H-J, J upper tubes (6). Skipped a couple of photos…

: It’s almost done. Just a few inner diagonals left.

: J bulkhead, inner diagonal UL-LR. This area of the frame is extremely strong as it has to support the suspension rockers and engine mounts.

: J bulkhead inner diagonals, LL-UR, 2 pieces

: H-J inner diagonals support the rear engine mounts.

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.”

YouTube Video Update 1

Posted by jjludemann on January 29, 2012

A couple of videos posted to YouTube. #1 gives an overview of the chassis as it stands, and #2 talks about the chassis jig table.

YouTube Update 1

YouTube Update 2

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.

By the Pricking of My Thumbs, Something Wicked This Way Comes

Posted by jjludemann on December 4, 2011

A mysterious form begins to take shape on the slab

Now it’s time to test one of the big unknowns of this project: can the top rails be formed in the shape of a complex 3D spline, and can the left and right sides be made to match? The CAD software won’t even allow a structural member in the shape of a spline, requiring them to be composed of straight sections and arc sections. Other exoskeleton cars have been built, but as far as I know always with a single curve in the main frame members. And of course a tubing bender is designed with the assumption that it will be used to form constant-radius segments. I believe this is the first car to be done this way, so I’ve put a lot of effort into the chassis jigs to get it right. The top rail spline is a key to the beauty of this design. To make a long story short, it is in fact possible to bend a 3D spline on a tubing bender. It just takes a lot of trial and error, patience, and about a day of work per rail. And luckily, overbending can be corrected by running the tube back through the bender, clocked 180 degrees.

“The pricking of my thumbs” is not entirely rhetorical. In fact I almost cut off my left thumb while building the top rails, so a word about safety. A tubing bender is a SERIOUS PIECE OF EQUIPMENT. It won’t even notice bones and flesh being fed into its’ rollers. I had already turned off the bender and reached to grab the tube as it was twisting on the way into the bender. The bender caught my glove and started pulling my thumb in, stopping at the last possible millisecond before inflicting permanent damage. It hurt and left a mark, but I was insanely lucky. So, 1.) Never wear gloves while using a tube bender. They protect you about as much as Saran Wrap, and it’s better to have your fleshy appendages dangling about unprotected to remind you of the danger. 2.) NEVER, NEVER touch the tube on the side being fed into the bender. Always handle the side being fed out. and 3.) Before pushing the “on” switch, stop, think, and say to yourself “I’m not going to become an amputee on this bend.”

So here's the problem: how do we make this straight tube fit all those notches located in 3D?

Left top frame rail about half done

Top left frame tube fitted to chassis jigs

Both top frame tubes bent to shape and matched to each other, in place on the chassis jigs. Now it's possible to get a feel for the size and shape of the car. It's really going to be beautiful!

The main frame rail, running from the front to the back of the car, is so light I can lift it with a single finger.

Sitting inside the chassis for the first time. Time to make vroom vroom noises.

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

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