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Triumph GT6 planned aeromods
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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: http://ecomodder.com/forum/attachmen...1&d=1276274604 http://ecomodder.com/forum/attachmen...1&d=1276274604 Aeromodded GT6 Mk II: http://ecomodder.com/forum/attachmen...1&d=1276273167 |
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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Toecutter -
Looks good : http://ecomodder.com/forum/member-cf...t6-overlay.jpg 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. CarloSW2 |
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... |
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: https://www.youtube.com/watch?v=remcU1f6p4w 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: https://i.imgur.com/E4pduC3.jpg https://i.imgur.com/QSbZyhI.jpg https://i.imgur.com/fhtXgK2.jpg More pics from 2013-2015: https://i.imgur.com/hmYMbwa.jpg https://i.imgur.com/1g7dh1a.jpg https://i.imgur.com/k5PUA2C.jpg https://i.imgur.com/J7J5NSS.jpg 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. |
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. S-10 photo album S10 4x4 Pick Up by George Kachadoorian | Photobucket |
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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. 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:
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Your fin looks like an antenna. How about following the GTI w12-650: https://ecomodder.com/forum/member-f...w12-650-16.jpg 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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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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Maybe just salvage an old liquid cooled PC and coil a loop around the motor? Building a Custom Water Cooling Gaming PC: Step by Step 2018 Beginner's Guide https://www.build-gaming-computers.c...ooling-pc.html https://www.build-gaming-computers.c...lwiFZXBsUj.jpg |
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2-4. Excellent questions. |
I'd look hard at a Bonneville-style spoiler before messing with that nice greenhouse.
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In the GTI w12-650 example the black bubble top would be the existing top. The wing could spring off the rear fenders tops. It would be like the unholy offspring of a Dodge Charger Daytona and a Bertone BAT.
https://upload.wikimedia.org/wikiped...f1/BATcars.jpg https://en.wikipedia.org/wiki/Alfa_Romeo_BAT Frank Lee: sorry about the file size. |
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I'm wondering how I would shape such a thing for it to actually be effective... |
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I agree that it is a shame to mess with the greenhouse, but do not see a way around it with such ambitious Cd goals. Lowering his lofty aspirations is the only real alternative, isn't it? Personally, I like the car the way it is and would not change it's looks. However, it's not my car. NOTE: Speaking of my own car, I studied a version of a raise Bonneville plane, it just happens to look like a wing but is not intended to act as one. This identity confusion may have prevented others from understanding my intent. See attachments. Perhaps such a device could be used on this Triumph. NOT MY CAR: https://ecomodder.com/forum/showthre...ler-34390.html https://ecomodder.com/forum/member-f...bonnevette.jpg https://ecomodder.com/forum/showthre...e-36229-3.html https://ecomodder.com/forum/attachme...p;d=1524146426 https://ecomodder.com/forum/attachme...p;d=1524146356 https://ecomodder.com/forum/attachme...p;d=1523144892 Image directly above is different designs to illustrate template fitting. One might call the two images above that (using Sponge Bob) a raised platform Bonneville spoiler plane in lieu of the more traditional one seen on the Corvette (far above) that is simply an extension of the trunk plane with perhaps some winglets to contain or delay vortex swirls. https://ecomodder.com/forum/attachme...p;d=1548773465 EDIT-2: I found another thread were people were discussing similar concepts. Flat Bonneville-type spoiler https://ecomodder.com/forum/showthre...-14946-12.html https://ecomodder.com/forum/attachme...p;d=1306807744 https://ecomodder.com/forum/attachme...p;d=1306807744 https://ecomodder.com/forum/member-c...th-overlay.jpg https://ecomodder.com/forum/member-c...il-lowered.jpg Once again these examples do not maintain constant air attachment and are considered less describable than full Kammbacks. EDIT-3: Same idea, just not done real pretty. https://ecomodder.com/forum/showthre...ler-14946.html http://i3.photobucket.com/albums/y93...y/Picture7.jpg A more graceful example. https://ecomodder.com/forum/showthre...r-14946-4.html http://image.hotrod.com/f/9349073+w7...smoke_wand.jpg |
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https://www.motortrend.com/cars/volvo/c30/2013/ https://st.motortrend.com/uploads/si...rters-view.jpg Going back to the wing that isn't a wing idea I was exploring on the Porsche and evident on the Ford Escort RS, exactly how less effective is it than a Kammback? https://topworldauto.com/cars/ford/f...otos.html#gp/5 https://topworldauto.com/pics/Ford/f...cort-rs-06.jpg https://topworldauto.com/cars/ford/f...tos.html#gp/32 https://topworldauto.com/photos/10/2...orth_46b21.jpg https://topworldauto.com/cars/ford/f...tos.html#gp/33 https://topworldauto.com/photos/4b/e...deos_0438f.jpg https://topworldauto.com/cars/ford/f...tos.html#gp/35 https://topworldauto.com/photos/02/5...orth_9c583.jpg |
Probably do better using forced air cooling through the motor, rather than liquid cooling the exterior. Exterior cooling will do little for the brushes and rotor.
If you need more power, I'd suggest looking for a (used) larger motor. I'd think one could be had for a few hundred bucks, since DC has gone out of style... |
I'm eventually going to upgrade the motor/controller when money permits.
Cutting the battery pack down to 144V to reduce weight and then installing a NetGain Hyper9 synchronous reluctance AC motor/controller would really do wonders for its efficiency. I'd have a system that could allow me to keep the transmission, while able to do 0-60 mph < 6 seconds and top out at almost 150 mph. 1/4 mile time would be in the upper 13s. And perhaps I'd get a range of 130-150 miles on a charge. AND the car would weigh less than it did stock. Were money no object, I could use TWO of these systems and delete the transmission, and possibly do 12s in the 1/4 mile with it. I've also been considering all of the excellent input everyone here has added to the thread and will be working on the design of a spoiler system that doesn't ruin the greenhouse. As long as I can get a CdA of under 0.3, this could be doable! I don't think it's unreasonable considering the ADU1B LeMans Spitfire had a Cd of 0.32, and Jigsaw Racing who produces replica pieces to install on Triumph Spitfires quoted one doing 137 mph on 111 horsepower, and the math works out close. |
I didn't know what a reluctance motor was until about a week ago. In my typical fashion, I didn't pay any attention to a technology that was out of my price range...none what so ever. Took one look at Paul's AC controller thread and assumed it was for induction...I mean, that's what Tesla runs as did a few others; assumed the rest were running a form of brushless DC. Oops. Very close, very similar, but not quite...
FWIW, the netgain, like most of the others these days, is not a simple reluctance motor...they call it a "Synchronous Reluctance Internal Permanent Magnet (SRIPM)" motor. The permanent magnets are equally important as the reluctance side of things. And to make matters worse, there are other names for the same thing! I can thank google for sniffing my searches and recommending a couple of youtube posts, including Tesla's "new" motor tech...which appears to have taken them a few years longer than everyone else to adopt, unless that was just on the model X which the video was about. Anyway, just looked at the Netgain motors. The $4k US is prohibitive to me, at least for a just-for-the-fun-of-it project, but...nice efficiency map. You'd basically be running in the >85% area of the map most of the time, compared to a BLDC which would max out there. That's impressive. And all by hiding magnets inside of laminations...I wonder why it took so long to figure that out and bring it to the market. Ok, I know switching speeds/losses had something to do with it, but still...oh, and that Netgain controller only weighing 9lbs is also impressive, for the power output. I gotta go, I'm drooling and this is making my head hurt to think about! |
Zombie thread lives again?
Have you made any decision on the aerodynamics? I see you'd liked the bat-wing towel rack idea. I'm still hoarding a 1958 Beetle and an electric drivetrain. I also figured to make it weigh less than the stock vehicle. By using a 98lb 68hp single speed rear axle out of a Lexus. How does your Hyper9/transmission compare? Stubby79 — Since you mention it, here's the Lexus part: https://ecomodder.com/forum/member-f...mpare-size.jpg It has the anti-back EMF buried magnets. It's the one on the right. :) Here's the thread: :cool: Hot-rodding the Toyota MGR |
I had not seen this thread before but I find it interesting because I had a couple of Mk III GT for 20 years or so.
I made some perspex cowls to go over the headlights, modelled on the items used by the works Spitfires that competed at Le Mans back in the 1960s. At normal road speeds they made little difference but at the speeds you are talking about they would be good. I am not convinced of the need for a dorsal ridge. The Mk III at least was quite stable in a straight line at 100 MPH. Cornering stability is another matter, particularly on the Mk II. The rear wheels were prone to tuck under if you lifted off mid corner, causing dramatic oversteer. A friend with a Mk II fitted the lower rear wishbones from a Mk III and reported that this was a major improvement, so you might consider doing that, or something similar. Note that not all Mk IIIs had the rear lower wishones - later cars had a wider track instead. What are your plans for the underside of the car? I made & fitted some panels that smoothed things out and I think helped. It is easy to fit this sort of thing because there is no shortage of places to fix things to the chassiss. Another oddity with the GT6 is tyres. The Mk III at least was sensitive to tyres and did not always react as you would expect to a change of rubber. Indeed it was sometimes counter-intuitive; for example, increasing tyre pressures on some tyres gave better grip in the wet on sprint & hillclimb competitions. With other cars it was normal to drop the pressures. I have no idea how you would find out what modern tyres would suit the car best without some expensive experimentation. Do keep the thread updated; I am interested to see your results. |
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OK, I wasn't too clear: I meant wet roads rather than enough water to cause hydroplaning. In fact the possibility of hydroplaning didn't even occur to me when I wrote my post yesterday.
If you can discount aquaplaning it is surprising how much traction you can gain by dropping pressures when grip is low. In extreme conditions, such as on ice or grass, dropping the pressures very low can get you moving when you are otherwise stuck. In "normal" wet conditions a slight drop in pressures will usually improve things. I can't comment on why that is so. |
GT6
I believe I have a GT6 analysis at home somewhere. It's definitely a 'pseudo-Jaray form, with separated flow ( although it probably has good rear outward vision.
* If you're going to do a template comparison, use the 2013 version with the 'faster', more aggressive roofline. * A look at as many cars shaped similarly and cars near Cd 0.25 will give you clues. Carl Breer's DeSoto Airflow test mule of 1934, Cd 0.51- Cd 0.263- Cd0.244. Panhard Dyna Shelby Cobra Daytona Coupe 1968 Toyota 2000 GT 1970 Citroen SM 1973 Rovomobil 1975 Ferrari Cr 25 1980 Ford Probe 1980 VW 2000 1982 GM Aero X 2000 Insight-I 2010 KIA Ray concept 2011 Hyundai Sonata Hybrid 2012 Tesla Model S 2015 SCION FR-S 2016 Renault EOLAB 2009 Prius-III 2021 Porsche Taycan Turbo You're kinda where CAR and DRIVER was in March,1974, with the Ford Pinto: *wrap-around airdam * grille-block * cooling fan is NA, as you're going electric * headlight covers * rear spoiler ------------------------------------------------------------------------------------ Then Pontiac's 1983 Trans Am Firebird's: * matching rocker panels with air deflectors ( slab-sides ) * aero wheel covers * most 'narrow' tires that you can 'safely' operate ------------------------------------------------------------------------------------ As much belly pan as you can. Rear diffuser. I like Frank Lee's comment about simply extending the rear. Flying-buttress C-pillar extensions along a more streamlined contour above the Bonneville-spoiler, to 'sculpt' the captured-vortex there. Rear skirts. Minimum front wheelhouse arch-to-tire gaps. 'Tesla-esque' side mirrors, or SCCA racing mirrors. Get them at least 80mm away from the body. ----------------------------------------------------------------------------------- I got the CRX to an estimated Cd 0.235 as an ICE vehicle pretty easily. I can't imagine that you couldn't best that.;) |
GT6 aero
I ran across my GT6 drawing last night. It's definitely pseudo-Jaray, with a very aggressive roofline contour.
By 1989, Porsche was able to get their 911 from Cd 0.40, down to Cd 0.32, with very exacting detail to cooling inlets and underbody smoothing. And it doesn't have the front cooling system penalty of the Triumph. I couldn't find a definitive drag coefficient for the GT6. Cds for the Spitfire are not parsed out with respect to whether measured as the top-down roadster, or with the rag-top up. Carrol Shelby's AC Cobra roadster is estimated at around Cd 0.65. As the Peter Brock, AC Cobra Daytona Coupe, an estimated Cd 0.42. As an EV, losing the cooling drag, and smoothing the exhaustless belly, Cd 0.32 seems reasonable. Skirts and wheel fairings, as with the circa 1962 Panhard Deutsche & Bonnet LeMans Coupe could push the Cd lower. Extending the roofline, like Carl Breer did with the 1934 Chrysler DeSoto aerodynamic test mule would definitely do it. They got a Cd 0.51 car down to Cd 0.262 as a chopped-off Kammback, and Cd 0.244 with the boat-tail stinger. ( A Tesla Model S in 1934! ) |
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