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Old 06-11-2010, 12:46 PM   #1 (permalink)
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Triumph GT6 planned aeromods

I have an EV conversion in progress, and in order to maximize its range, I will be making extensive use of aerodynamic modifications.

My goal, which is to achieve 100 miles range on lead acid batteries at 60 mph to 100% DoD, will not be possible unless I get Cd at or below 0.25.

I have made two drawings, both drawn to scale, one of the GT6 stock, and another with the proposed aerodynamic modifications. On the aeromodded version, I included a dorsal ridge for stability; I'm intent on exceeding 130 mph in this car and I'm not keen on the idea of a stray gust knocking me off course.

Does the Kamm-back appear to be the correct angle? Any concerns? I want to make sure I get this right before I start drilling holes into the body to mount this(I will have cardboard mockups tuft tested once the car is registered and road legal, before making the fiberglass pieces).

Stock GT6 Mk II:




Aeromodded GT6 Mk II:


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Old 06-11-2010, 06:04 PM   #2 (permalink)
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The smoothed up, sealed up front end looks good. Most modern cars I've seen have the spats in front of the front tires slightly more toward the center of the vehicle. I like the rear wheel skirts but I am not too sure about the angle of the Kammback. I don't have the aerodynamic template right in front of me but it looks like it should be steeper and should taper in on the sides too.
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The power needed to push an object through a fluid increases as the cube of the velocity. Mechanical friction increases as the square, so increasing speed requires progressively more power.
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Old 06-11-2010, 06:46 PM   #3 (permalink)
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Toecutter -

Looks good :



I got mixed up for a while because I didn't realize that you lowered the green version. That changes the scale of the overlay, so the lines don't line up as well.

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Old 06-22-2010, 02:58 AM   #4 (permalink)
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Thanks! I'm saving that bottom image as a template for proposals on other vehicles as well, if you don't mind.

I can't wait to see how this body turns out when I finally build it. Given that my job situation has gone bad this year and I need an income source once again before I can spend large sums of money, my Triumph is going to be on the road initially as a 72V conversion; with the right amount of drag reduction and an added 5th gear, 80+ mph is not out of the question, when the norm for a 72V conversion is around 50-60 mph top speed(some 72V examples have exceeded 70 mph, but are not the norm).

The first aeromods that I'm going to permanently install are going to go on my Benz, but I have no way to conveniently measure distance any longer due to a gear set in my odometer having broken. I can, however, plan some long trips beforehand and map the route on google, from one fuel station to another, and fill it up at the very first station, as I have done in the past to get data.

My main concern is figuring out how to attach them with minimal intrusiveness into my car's body. I'm probably going to have to drill holes on the Benz too; I don't mind much, considering I got the car for $1,200, someone was allegedly murdered in it before I bought it, and it's seen its share of hookers courtesy of the previous owner! I'm not intent on restoring it to mint condition...
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Old 01-28-2019, 01:36 AM   #5 (permalink)
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It only ran on lead acid batteries a few times, using 36V and then 48V, with batteries that were ready for the scrapyard and couldn't do more than 100A or so.

That was in 2012. Here's a video:



It had some mechanical issues that have been mostly solved since, and those tired old lead acid batteries made it VERY slow.

I ended up buying some CALB CA100FIs in 2013. The car still isn't finished.

Anyway, here are some pictures from 2016:





More pics from 2013-2015:






In it now is a Prestolite MTC4001 series DC motor modified for high voltage operation, Soliton 1 controller, and 65 CALB CA100FI batteries. It currently peels out in top gear at a stop and fishtails effortlessly at full throttle. I will be adding a Quaife limited slip differential to correct its tendency to fishtail at full throttle once funding is available.

I designed this conversion back in high school to use lead acid batteries, but didn't get it anywhere near completion until long after college due to lack of funds and/or time.

I had money to finish it last year, but I ended up having to use it to save my mother's house after some family members drained her money for drug habits, and she can't walk or work. I'm currently unemployed again and haven't had luck finding work and have been living off my savings.

I'm currently trying to sell my prized Mercedes 300 SDL for cash to finish my electric velomobile and get the GT6 legal and close to completion.

In the long run, I want to get a transmission delete and twin synchronous reluctance motors with high efficiency or maybe just plain old twin series DC WarP 9's. I want to make this thing scary to floor it in. It also needs a roll cage.
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Old 01-28-2019, 11:42 AM   #6 (permalink)
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Nice project, I see that you updated it from 2010 to 2019.

That's called dedication.

That old video showed some road under your feet, a full belly pan may resolve that condition while improving your Cd.

130 mph?

You are taking care of a great deal of lift by following the aero-template but I would feel better if there was a front chin splitter for some nose down force to help keep the car planted at high speed.

When you seal up the front grille, make sure it's air-tight, even a little air penetrating though has a habit of being noticeable.

I'm just saying this based on my S-10's blocked up air inlets, sometimes it needs to be resealed based on how the truck feels on the highway. I can tell when a gap has formed - not kidding.

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Old 01-28-2019, 02:52 PM   #7 (permalink)
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Quote:
Originally Posted by kach22i View Post
Nice project, I see that you updated it from 2010 to 2019.

That's called dedication.
I drew the first circuit diagrams for this back in 2002/2003 when I was a 17 year old high school student...

Quote:
That old video showed some road under your feet, a full belly pan may resolve that condition while improving your Cd.
I have mock-ups made out of coroplast for most of my pieces. I haven't had a chance to try them yet.

Quote:
130 mph?

You are taking care of a great deal of lift by following the aero-template but I would feel better if there was a front chin splitter for some nose down force to help keep the car planted at high speed.
Since I ended up getting LiFePO4 instead of PbA, I'm actually planning to go faster now... If I get Cd down to 0.25 and frontal area ends up at 14.7 sq ft, theoretical top speed with that Prestolite making 120 horsepower(calculated, not dynoed) could be north of 150...

The continuous power rating of the motor isn't all that great, so racing it could overheat it in under 5 minutes. Max continuous flat ground cruising speed should be around 85-90 mph, with hills dramatically lowering that.

I don't plan to keep that motor forever, and going to a nice AC setup or dual WarP 9s with series/parallel shifting is in order in the longer term.

Quote:
When you seal up the front grille, make sure it's air-tight, even a little air penetrating though has a habit of being noticeable.
There will be one small duct for motor cooling on the underside of the car.
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Old 01-28-2019, 06:07 PM   #8 (permalink)
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Quote:
Originally Posted by kach22i
You are taking care of a great deal of lift by following the aero-template but I would feel better if there was a front chin splitter for some nose down force to help keep the car planted at high speed.
I agree with the splitter, but not following Thee Template. If you were making the top from scratch maybe, but since you have an existing architecture I'd focus on having the top taper match the existing side taper. This will prevent vortexes rolling up or down off the drip rail.

Your fin looks like an antenna. How about following the GTI w12-650:



You already have the bubble top part, add a close-coupled wing and flying buttresses. make a proper shuttlecock out of it.
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Old 01-28-2019, 06:15 PM   #9 (permalink)
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Quote:
Originally Posted by freebeard View Post
......I'd focus on having the top taper match the existing side taper. This will prevent vortexes rolling up or down off the drip rail.
Yea, someone else mentioned something similar, but can that be done with the existing side glass in place?

In either case, large radius corners should help, but if true then why are the original Honda Insight and all versions of the Prius so sharp cornered?

Is the taper being equal top and side more important than a radius edge?

Does successful execution of one mean you do not need the other?
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Old 01-28-2019, 06:22 PM   #10 (permalink)
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Quote:
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The continuous power rating of the motor isn't all that great, so racing it could overheat it in under 5 minutes.
This is probably a stupid question, but can one retrofit a cooling system to such a motor?

Maybe just salvage an old liquid cooled PC and coil a loop around the motor?

Building a Custom Water Cooling Gaming PC:
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