The Aerodynamic Streamlining Template Discussion

[kach22i]

Originally Posted by aerohead

It's unfortunate that we didn't have more image contrast..........

I was just thinking of that.

Perhaps a dark matte gray model and white smoke, or light matte gray model and black smoke would film better.

The white model had a glossy finish to it and obscured the smoke at times.

Going into the past (2011), Aerohead answered my questions and a skeptical and intuitive thinking "Winkosmosis" regarding aero-template use.

How To Line Up Template - Sports Car Design
https://ecomodder.com/forum/showthre...ign-18632.html

I tossed out the clay car model posted in that thread along with a couple dozen other models (cars, aircraft, hovercraft and passive solar houses) when I moved last year.

Just no space in the new house, plus they were all getting distressed and reflected my old thinking.

New chapter has begun.

[Cd]

Phil, welcome back. 🙂
I hadn't seen this particular Youtube video, and wasn't aware you tested the truck without the mirror.
It looks as though you also taped up the gap behind the bed in this test.
What was your best Cd on the truck, and what Cd of the template model you had tested ?

[freebeard]

5:27 — 100lb down on the front wheels, 200lb lift on the rear at 200mph?

Wasn't the design intended to be neutral? Down on the broad end, (2x) up on the narrow end?

[aerohead]

Originally Posted by Cd

Phil, welcome back. ��
I hadn't seen this particular Youtube video, and wasn't aware you tested the truck without the mirror.
It looks as though you also taped up the gap behind the bed in this test.
What was your best Cd on the truck, and what Cd of the template model you had tested ?

Here are some of the raw numbers : Trip-one
1) 840- pound weight penalty
2) Cd 0.2675 as driven, Spirit-I
3) Cd 0.251 with folded OEM mirrors
4) Cd 0.2435 with OEM mirror delete
5) 30-pounds downforce @ front @ 135-mph ( on a 4220-pound vehicle )
6) 22-pounds rear lift @ rear @ 135-mph ( on a 4220-pound vehicle )
7) Toyota Prius calibration model = Cd 0.285 @ DARKO
8) Toyota Prius calibration model = Cd 0.26 @ A2 Wind Tunnel
9) Toyota Prius calibration model = Cd 0.25 @ Toyota full-scale wind tunnel
------------------------------------------------------------------------------------
Trip-two:
10) 100% grille block = Delta Cd 0.027
11) Dodge Viper windshield / cowl seal = Delta Cd 0.005
12) Dual SCCA racing mirror delete = Delta Cd 0.010
13) 'Unibody' simulation ( cab-to-bed gap seal ) = Delta Cd 0.016
14) Cut line, body gap taping = Delta Cd 0.000
15) Cd 0.3445 as driven ( no boat-tail, no stinger ) If lift was measured we didn't discuss it. I wasn't interested, as without the tail and stinger, she was 'incomplete.' If lift data was recorded, it will be on the CD that Layne presented us.
15-A ) For the 4,687-mile trip, Spirit-II returned:
* 29.435-mpg @ 70-mph
* 32.798-mpg @ 65-mph
* 36.968-mpg @ 55-mph
* 31.814-mpg trip average
All on Regular Unleaded gasoline
-------------------------------------------------------------------------------------
If one takes the data from the two trips and associates it with the original numbers, the following are indicated:
16) Spirit with Dodge Viper windshield/ cowl seal = Cd 0.2625
17) Number ( 16) Spirit with 'cameras' = Cd 0.2525
18) Number ( 17 ) Spirit as a BEV ( cooling delete ) = Cd 0.2255
19) Number ( 18 ) Spirit with restored belly / diffuser function = Cd 0.1755
20) Number ( 19) Spirit with 'Unibody' = Cd 0.1595
21) Number ( 20 ) Spirit with stinger = Cd 0.1325
------------------------------------------------------------------------------------
22) If the Prius calibration model quanta is factored in, it suggests that if Spirit was tested in the A2 Wind tunnel, under the number 21) configuration it might indicate Cd 0.1208, and Cd 0.1161 at the Toyota wind tunnel.
These are all just estimates, but the speed and mpg suggest a significant drag reduction compared to the OEM configuration. Spirit has returned 39.9 mpg on three occasions. 900-miles plus on a tank of gas gets kinda interesting.
--------------------------------------------------------------------------------------
23) the 'baby' template, long-tail, 1/3rd-scale model was Cd 0.1209
24) the ' baby' template, short-tail was Cd 0.148 ( which includes complete loss of the wheel fairing boat-tailing ).
--------------------------------------------------------------------------------------
The new stinger is complete. The new boat-tail lacks about a months work to complete. In order to get the new tail on the truck will require some concrete flooring and a gantry crane in the shop and a low-water crossing driveway repair. I'm doing a pit in the shop floor as well.
If I can keep the truck running, I'll try for the A2 Wind Tunnel, since we've lost DARKO. I've cut all extraneous spending, and am saving for a used EV. I've got green energy at home and would like to be driving on it ASAP.

[aerohead]

Originally Posted by freebeard

5:27 — 100lb down on the front wheels, 200lb lift on the rear at 200mph?

Wasn't the design intended to be neutral? Down on the broad end, (2x) up on the narrow end?

numbers are posted now. Thanks.

[freebeard]

Baby Template, not Spirit?

In order to get the new tail on the truck will require some concrete flooring and a gantry crane in the shop and a low-water crossing driveway repair. I'm doing a pit in the shop floor as well.

You do seem to overbuild things. What happens to front/rear weight distribution?

[aerohead]

Originally Posted by freebeard

Baby Template, not Spirit?

You do seem to overbuild things. What happens to front/rear weight distribution?

Baby's done. There's nothing really left to do that would be worth the cost and hardship getting it to and from North Carolina. CUER has the numbers. Baby would just be redundant.
If I don't get Spirit back I'll lose around 1,000-hours of fabrication time with nothing to show for it. Too hard to swallow.
As to overbuild, Baby had to survive the commute, allow for attachment to the tunnel without destruction, be strong enough to survive the cantilevered load of the tail when added, not warp in the North Texas humidity, roll on its own, etc.. I can barely lift it.
I could have used Baby as a buck, then another 800-hours to make three sets of tooling, to cast three sets of lightweight parts, plus a completely new chassis to roll on. There's another 1,000-hours. She's done!
The weight actually gave me almost a perfect 50-50 weight distribution. She feels like a large CRX.

[freebeard]

I'd like to try stich-and-glue construction:


Stitch & Glue Kayak | New Concept Model

If there's another round of plague money, I'm thinking about getting a Maslow CNC router.


https://www.maslowcnc.com/

It would cost less that restoring my Shopsmith. And it doesn't take much floor space.

[Cd]

I know in the past you had discussed looking for a Dodge Viper rear window to use as a front windshield.
Was it easy to remove the defroster wires on the glass ?
I missed seeing a picture of the truck with it mounted.
How have you handled the wipers ?
Also, why is DARKO no longer available ?
And finally, to get back to the posted topic of the template, what was the Cd of the template model ?
( Appologies if I didn't see that you had posted it already. )

[freebeard]

How about we discuss this issue (on this thread instead of the announcement thread) for the next few days?

Has the thread reached it's sell-by date yet?


https://ecomodder.com/forum/showthre...tml#post532128

IIRC no benefit accrued.