Baby template car for DARKO 2016
 

I've set my mind to a return trip to DARKO Technologies wind tunnel in 2016.
I've thought of at least 16 additional mods for the T-100 to test.
Since I'm going,it would be efficient to have at least 1-additional vehicle to test while I'm there (like we did with Gary's Prius).
I figured out that a 1/3rd-scale 'Template'-mobile will fit in the back of the T-100.
She'd be 21" high,42" wide,and just shy of 8' in length.Built up from plywood,foam,and fiberglass,she wouldn't weigh much.I've already located some 'scale' wheels at Harbor Freight Tools.
The 76-mph airspeed at DARKO is plenty enough to achieve critical Reynolds number and accurate Cd.
The model would be a way to verify the 'Templates' actual aero characteristics.
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Also,if there's a member in the Salt Lake City area with a bone stock, 1st-gen Honda Insight,it would be great to do a meetup at the tunnel and throw your car onto the load cells and see how it's Cd compares to the A2 value from North Carolina.I'd cover the cost.
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It allows one year for fabrication and even at my glacial pace,I think I can get it all ready by then.:p

Can't wait for the results!

Care to elaborate on the 16 mods you want to do to the 'yota?

That sounds great. I would also like to know the 16 mods you are planning for the T-100.

This is a great idea. My request is that you consider a geodesic construction. It can be laid out as a flat pattern with darts and cut from a single sheet. That will self-assembly into an accurate surface. Much less work. :thumbup:

http://starship-enterprises.net/file...%20Pattern.jpg
http://starship-enterprises.net/files/3f%20icosa%20Peel%20Pattern.jpg

I can provide all the relevant edge lengths for a prolated ellipsoid.

'What do you think, sirs?'

geodesic
 

It would be fun to see the geodesic structure under smoke,'n also get some numbers,but if I'm gonna make my target I better stick with what I know.
The model has got to be as close a representation of the drawings as I can do,so as not to introduce any unknowns.
The velocity and pressure profiles of a streamline half-body are dependent upon the compound curvature.
Windshield wipers and roll-down windows would need more 'conventional' surroundings.
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IF a geodesic 1/3rd model were to appear in Ogden,Utah,September,2016,we'd be impelled to get it into the tunnel,and I'd sure help underwrite the cost.(hint-hint,wink-wink!) Plus,there's some pretty good Mexican food nearby.:)

16-mods
 

The list is at home but here goes:
*reworked airdam with belly and edge radius
*grille plug
*improved cooling ductwork
*reconfigured hood blister,widened out to edge of A-pillars,with NACA submerged-inlet /ventilation duct-to cowl inlet
*faux GTP full-compound,triple-curvature windscreen
*faux 'active' windshield wiper cowl area fairing
*new mini-mirrors
*mirror delete
*faux flush glass
*tape all seam and cut lines
*full gap closure between cab and bed
*restore missing belly pan section
*add belly pans to lower A-arms
*add urethane pan sections around rear axle gaps
*faux 'active' wheel fairings(before and after front wheels)
*ditto rear wheels
*lowered diffuser addition to boat tail (2.8-degree)
*add blended flow fence into lower perimeter to close in Coke-bottling
*lower rear skirts to former full depth and add integrated flow fence
*reconfigured aeroshell
*reconfigured boat tail
*reconfigured boat tail stinger (full-length)
*simulated suspension drop (deflate the tires)
Looks like I'm at 23 things to test,plus the model.

I assume the "faux" components would essentially be non-functional and used for the wind tunnel test, but the other components would be functional for use when driving the truck?

faux
 

Yes,some of the things I want to test would never survive on the road unless they were active,to accommodate weather, road clearance,or DOT regulations.
The windshield would have to be 'real.'
I can't lower the truck so I'll just let the air out of the tires 'n see if it shows on the computer screen.
Flush glass isn't going to happen.Nor a pliable cab/ bed gap-filler,or unit construction.
Lots of Gorrilla tape and aluminum sheet,Formular,etc.,composite mockups.
I will be able to simulate a 'future' in which these things were part of a production vehicle.

Coincidentally, about the size of a single wheel trailer for a VW Beetle. Wink, wink; indeed.

Edit: Could I make a rear-steer reverse tricycle and put a ball hitch on a nose probe and have it track successfully, a least going forward?

Wait a minute—42"x3 is 10' 6" wide.

What size are your candidate wheels?

tracking/wheels
 

I think that for towing,the front wheels would have to be free to turn and rear wheel fixed,as when pulling with a towbar,or with fixed front wheels,allowing the rear to turn as on Bam's 1-wheeler.
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The wheels are about 8.5" X 2.5".

I'm taking this semi-seriously. The biggest intellectual hurdle is figuring out where I would park the thing. :)

I want to put a hitch on my car and restore the Westy trailer anyway, and it has a steel frame supporting a plywood box. The tongue and axle bolt together and there is a 2x2" wooden joist supporting the back of the box. Deleting the box would make it a dolly. The tongue is 3' and the axle is 53" to the outside of the trailing arms. The wheels are 16x5".

Your wheels are smaller, and you plan on four, right? I was thinking of a towable model but to match your dimensions it would have to be trailerable.

My thought experiment is hang a flag on a long pole off the back of a short trailer. When the tow vehicle turns the trailer will follow, but the flag will be tangent to the curve and outside it. The steps would be:

1. Add a trailer hitch (and take the chatter out of the clutch)
2. Restore the Westy trailer frame (new elastomeric snubbers and bearings)
3. An asymmetrical pyramid made out of angle iron from Hollywood bed frames
4. A two frequency geodesic made of luan plywood and aluminum taped edges
5. Over that—a removable thin 4v shell
6. Bonus: finally a sock over that that could inflate to a compound curve.

If the front wheels were in blisters a 4x10ft model would be half-scale. A Vespa front fork would be a good match for the Westphalia wheel size.

parking
 

Any Wal Mart will allow overnight 'camping' in their parking lots.
The larger LOVEs truck/car stations allow overnight stays.(if you park near the 18-wheelers,their engine noise drowns out distracting noises)

Hold on. I need to start with a trailer hitch.

....or maybe do 1/3 scale and put it on a roof rack.

How about lopping some of the tail off the template to simulate what is most often done with tails in the real world? Or is that well enough established?

The question to be answered by my following aerohead's dimensions would be the difference between a pointed tail like The Template and a rounded tail like the Dymaxion.

Truncations are do-able. Or one could add a strap-on cone, while [re-]considering the fineness ratio.

The larger question is the effect of creases in the surface. A 3v sphere has a break angle of 360/20 or 18°. A prolated sphere will be sharper at the ends and smoother in the middle, with the limit case being a compound curve. I want to see if there's any 'dimple' effect with the lower frequency. A 2v would be about as angular as the F-117.

lopping off
 

I want to verify the shape exactly as drawn.If I can fit it into the schedule,I'll do removable tail sections,but that doubles the difficulty in fabrication at this scale of build.

truncations
 

I've been struggling with an English translation of Kamm's research and what I can say is, 'don't do 'rounded' truncations.Make the cut as if you'd do it with a bread knife.Straight chop.

One of the forum members once tried a rounded trailer rear - it made it rather unstable.

You get Coanda effect as air flows over the rounded surface, pulling at the surface trying to lift it.
As the air flow is never even L/R it pulls more on one end, then on the other ...

Make the model full length and then cut a 20% truncation and tape it back together.

Double bulkheads at the point of the slice, for strength.

cut
 

They'd never allow it in the tunnel for safety reasons.
It will have to be designed into the build with the facility for robust attachment.And I have no way to cut off the tail with any degree of accuracy at this sort of scale.
Perhaps a 2018 trip.We'll have to see.

li'l update
 

* purchased the wheels
*I have axle stock on hand
*I have 1-sheet of plywood on hand
*Tom Burkland is assisting me with regards to model attachment considerations for the tunnel.
*I'll be sending out a set of drawings to DARKO so everyone can see what the 'plan' is for the project.
*I've already widened the body to accommodate a 42-inch front track to fit the front load cell support troughs.
*I bought fresh blades for the recip saw and will be cutting up both the belly tank and Bonanza fuselage for scrap,raise a little cash,and make some room around the place.

To quote the Beatles (Revolution), "We'd all love to see the plan." How much were the wheels?

With a scale in 32nds of an inch you can measure to 1/64th, or even 1/100th. I used to do that when I was making Geodesic dome kits. I got 1/32nd accuracy over 40ft. I doubt I could today.

plan/wheels
 

*I'm doing a 3-view drawing to send to DARKO.It' not to scale,just to give them an idea and work out attachment.I hope to get it out tomorrow and I'll try 'n get it scanned for Saturday posting here at the forum.They're not meant to be a blueprint and a bunch of morphing is going to happen to respect all the project constraints.Compromises.
*The wheels were $7.50-each plus the governor's tribute.They'd be equivalent to around a 205/ 75 R-15,like on the truck.Solid rubber on steel wheels,and a tread pattern.They're really stinky too! Really nasty odor!
Since most of the wheels will be concealed within the fairings and skirts I feel like there'd be some wiggle room here with respect to dimensional accuracy.

Drawings are in the mail
 

I talked to Layne Christensen at DARKO by phone this morning.We went over attachment details.
I finalized the drawings,went ahead with dimensions.
Layne said that once they see the images and numbers,that they'll come up with an attachment strategy for me.
I couldn't build what I wanted and have it fit onto the load cell bearing members directly and still be able to transport it within the bed of the truck.
I reconfigured the drawings to fit the dimensions of the T-100 at full-'Template.'It's an abomination compared to a 'pure' pumpkin seed,but better represents 'real' vehicles.
The small frontal area of the model will reduce the maximum airspeed in the test section,but it will be enough for a supercritical Reynolds number,TBL, and stable Cd.
So,as to paraphrase Preston Tucker:'All I need now is a model!'
I'll also have to cut my aeroshell to add a rear hatch section,otherwise I'll never be able to get the model in or out.:p

3-view model drawing
 

Here's what I have so far.Will postpone fabrication 'til I get the thumbs up from the folks in Utah.
http://i1271.photobucket.com/albums/...Untitled_2.jpg

update
 

After a month I finally called up to DARKO.
The drawings arrived okay.Layne gave 'em to Tom to look over and Tom's so busy we haven't heard from him yet.
I'm not concerned.There's a lot of time yet.:)

As you approach the speed of light that's true. But the fineness ratio goes all to h*ll.

fineness
 

And you experience wallet dilation:p

Speaking of which, I'm trying to keep the car on the road I'd like to haul my 1/3rd model on. I'm starting to think I should park it and save the money to rent a pickup.

I could make the model recyclable and rent one way, then take a bus home.

model
 

As soon as you as you can finalize the footprint of the model,get some images to DARKO so they can figure out how to lash it down to the load cell troughs.They'll need some lead time to figure it out.Fun!:D

The only thing in question is the scale. I was thinking 1/3, to compare with your'n. 1/4 would be less materials.

I'm now past thinking about renting a pickup.We need to see wake-filling on a
Beetle body (someone has to do it). And I may be past the unreliable part. I took the car to the shop and they replaced the fuel pump with one that didn't look right and the lever arm broke as soon as they started it up. The second one had the fuel lines hooked up backward (because it was also not a direct replacement) and it fell apart in his hands when he tried to reverse the connection. So the third one looks right (it has the gold-anodized dome on top) and seem to be working.

I guess I'd gotten used to reliable transportation.

1/4-scale
 

It's gonna have to be at least 1/3rd-scale or we'll never see a critical Reynolds number and accurate Cd.:o

grave digging
 

*I sledge-hammered out what concrete I had in the shop where the T-100 mods will be created.
*Then I dug out the compacted rock sub layer with a wrecking bar.
*The concrete and rock became part of the driveway where one might have been 'stuck in the mud' before,carried out in half-5-gallon bucket loads.
*My 'indoor' oil-change pit is being expanded to create a larger pit,integrated into a level slab for taking measurements, fabrication,and installation.
*The dirt is becoming backfill for my earth-sheltered shack.
*Right now the pit is W= 36" X D= 14" X L= 108".
*I pulled the T-100 in over it Wednesday and crawled in for a look-see.
*It's better than I've ever had,but I'm going to expand the length to 144" and deepen it a bit more,then 'retest.'
*Since the excavation is 'indoors,' all the digging is by hand,in hard clay (gumbo).
*The loose plan,is to have everything concreted in by the first of March.
*At this time,I'll fall off the face of the Earth and disappear into full-time fabrication mode.
*In the meantime,I'll get everything I can think of online before I cutout.
*Right now,the passive solar shop area is staying well above outdoor ambient temps and this should improve as mods to the shop envelope evolve.I should be able to sling fiberglass, Bondo,and paint regardless of outdoor conditions.
(you rich guys,enjoy your hydraulic lifts!):D

Makes my back hurt just thinking about it.

I always liked the grease pit in the movie California Kid.

shop
 

Pasive solar shop eh? Sounds good any pics? I know my greenhouse can be 20 to 25 degrees above outside in the winter . (Lattitude 51ish) . Did i read that right, 14 inches deep? I guess just enough to lie down and get the work done, helps when vehicle is low. Interesting as i am concreting my shop floor this week, and thought about a pit. Dont think i will, but the heated slab should be nice to work on. (Looking at solar evac tubes to heat it)

pics/14
 

I'll do ecomodder a big favor by not posting images.Members who've been here will understand.:o
As the deciduous trees continue to lose their leaves I'll be seeing higher delta-T's between indoor/outdoor and I'm likin' things pretty well as it is.And there's more fenestration coming.
At 14-inches (taller than my car ramps),I could work under the vehicles okay right now,but more depth would be better for my back, which is pretty tore up after decades of construction work.I'm shooting for fully upright sitting,while on an adjustable-back support creeper.
I'll dig some more,pull the truck back in and see what that feels like.
Some Formular rigid foam would be nice under the concrete.
Your greenhouse sounds great!

That makes more sense than digging it out so you have to stand up all the time.

You'll need a smooth floor for the creeper. Are you going to pour walls or use cinder block, or ???

Extruded polystyrene and concrete, now you are speaking my language. I don't know what (if anything) you were thinking for the side walls, but 4" blocks dry stacked on the edges of your pit with surface bonding cement on the inside faces for strength would give a nice finished wall to your pit without too much effort.

walls
 

Once the bottom pad is placed,I'll tie in the vertical steel reinforcement, make a reinforced plywood form for the inner face of the walls,up level to the top of the upper slab elevation and pour all that as a monolith.
Then I'll have the elevation established for the rest of the flat work.
I'm gonna go ahead and run some conduit and at least a double-gang electrical box into one wall for power tools and lighting.
And a sump pit at one corner in case a Tsunami hits.