# Okay, so what SCALE are T-JETS, really?



## Dslot (Sep 2, 2007)

Looking at the what is h.o. scale 1/64 or 1/87? I'm seeing the usual answers - 
True model railroad HO scale - 1/87
Vibes about 1/76-1/80
Tjets - 1/72-1/76
AFX - about 1/64​
I've given these answers also, or similar ones. But this time I decided to a quick measure-and-calculate, just to see how accurate we are.

After looking for my vernier caliper for half an hour, I decided to use an adjustable clamp to get overall length, and measure the jaw spacing with a common ruler. Then I found specs for the actual car length. Car's length in inches divided by model's length in decimal inches equals the inverse of the scale. For example, the 68 Charger:
Car length (208") divided by model length (2.75") = 75.64
Invert and round to the nearest whole number = 1:76 scale

I grabbed a few examples and here are the results. 

JL copy of *62 Corvette* Vibrator = 1:78 scale 
*Shelby Cobra* 289 = 1:60
*Jaguar XK-140* - 176/2.36 = 1:75
Split-window *Corvette* - 175/2.56 = 1:68
*Jaguar XK-E* Coupe - 175/2.63 = 1:66 
Ford *GT 40 MkII* - 163/2.48 = 1:66
67 *Ford Galaxie* - 210/2.75 = 1:76
*Chaparral 2C* - 158/2.58 = 1:61
1963 *Lola GT* - 154/2.38 = 1:65
*Cheetah* length - ???/2.18, wheelbase 90/1.36 = 1:66
68 *Charger* - 208/2.75 = 1:76
60 *Tbird* - 205/2.32 = 1:88 wheelbase 113/.36 1:83
(this one seems fishy to me) 

This was just a quickie exercise. I haven't checked these figures, and anyone else is welcome to do so or add scale calculations for other models.

What surprised me was how many T-jets of those tested approached or even exceeded the 1:64 figure. I can't wait to see what the AFX representations of the smaller cars scale out to. But I don't have much variety in AFX bodies, so somebody else may have to do those calculations.

Remember this is just a simple length-of-body measurement. As I have said before, an HO slotcar can have different scales for length, width, height and wheelbase on the same model.

Crude, but interesting nonetheless, I think.

-- D


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## buzzinhornet (Jan 20, 2000)

Cool info D. :thumbsup:


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## ParkRNDL (Mar 20, 2002)

Very interesting. I wonder how the rest of the street cars stack up... I'd like to see if the SWB cars are all around 1:68 or so like the Corvette and the LWB cars are around 1:76 like the Galaxie. Or, compare the scale of the AW '68 Camaro to the scale of the Aurora '68 Camaro, and the scale of the AW Mach 1 to the scale of the Aurora Mach 1...

gotta break out one of them fussy little rulers... 

--rick


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## Bill Hall (Jan 6, 2007)

Cool post D.

We always knew liberties were taken in order to style certain models around the powerplant. How about a couple more when ya feel like cyphering?

VW Beetle, Mako, Tow Truck or Stake Bed


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## AfxToo (Aug 29, 2003)

> Remember this is just a simple length-of-body measurement. As I have said before, an HO slotcar can have different scales for length, width, height and wheelbase on the same model.


Yes, very crude. So the length alone is 33% interesting at best, with width and thickness being the other crude measures that would be interesting to know. In fact, the relative size of individually recognizable parts of the model is equally important as we've seen with models like the AW TJet VW bug, which has an unusually stubby rear end. As a scale model the combination of overall and individual proportions are the most important measure for evaluating how well the model depicts the actual object.


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## Dslot (Sep 2, 2007)

Bill sez:


> Cool post D.
> 
> We always knew liberties were taken in order to style certain models around the powerplant. How about a couple more when ya feel like cyphering?
> 
> VW Beetle, Mako, Tow Truck or Stake Bed


The Mako's probably easy enough, but if you want calculated scale on the Bug, you'll have to measure the model for me (length over bumpers), since I don't have an example. 

I'll take a look at my tow truck, but I'm not sure there was any standard model tow-truck that it was meant to represent, so scale length may be moot. The cab looks like an International Harvester, if memory serves, but I seem to remember that the tow truck configuration was not done by the original manufacturer, but was a conversion done by a variety of aftermarket companies. We may have to go with roof-height or something. 

-- D


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## foxkilo (Mar 27, 2008)

Although I love scale cars or better cars in one scale I have to accept that it is restricted by the size of the chassis. So in my case I've tried to find a compromise with 1/72 scale because many LWB Tjets and Faller are roughly that size and they go quite well with true scale buildings. BTW did you notice that older scale buildings are normally closer to 1/100 than 1/87? 
With 1/72 I got by now a big choice of manufacturers of diecast ones like Hongwell (Cararama, Schuco), Yat Ming, RealX which can be either straight converted to fit Tjets or used as the base for resine castings.
Anyway last night I tried mating a chassis to a Nissan Z360 I have two of and which I thought to be of the same manufacturer also one was sold as Schuco and the other as a Yat Ming. But although they are supposed to be the same they showed under close scrutiny some differances. The biggest one car is 1,3mm shorter and 0,5 mm less wide. I regard this as being quite substantial as they are supposed to be the same scale and they don't have the restrictions put on them by the chassis.

With regard to the conversion the body fits nicely on a Faller chassis as its LWB is inbetween the L and SWB of the Tjet. You just have make two kind of spacers to lengthen the posts and use long screws. The original posts of the diecast aline near perfect with the wholes on the Faller or Tjets. And the Yat ming bodies are of the srew on type.

Regards

Mario


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## SCJ (Jul 15, 1999)

LOL...

You want scale......measure the Vibe Semi, Thunderbike and Snowmobile!?!


-------------------------
www.SlotCarJohnnies.com


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## roadrner (Jul 21, 1999)

SCJ said:


> LOL...
> 
> You want scale......measure the Vibe Semi, Thunderbike and Snowmobile!?!
> 
> ...


 
:lol::lol: rr


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## NTxSlotCars (May 27, 2008)

Yeah, and how about those LifeLike dirt bikers and skateboarders?


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## Dslot (Sep 2, 2007)

I said:


Dslot said:


> The Mako's probably easy enough,


Hoo-hah! Not on the web. Not in my books. Nobody cares about the dimensions of one-off cars, apparently. :freak: I've got the same problem with the Cheetah.

Anybody got length measurements on the actual (1:1) 
* 1965 Chevrolet Mako Shark II*? 
Width, height and wheelbase would be nice, too.

Still need length, width, height, wheelbase of the Aurora VW bug, too.

Thanks, 
D


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## Dslot (Sep 2, 2007)

Getting close on figuring out the vibe Tow Truck.


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## Dslot (Sep 2, 2007)

Well, I learned to work a spreadsheet app, just for this project. (Dammitt, Jim, I'm an _artist_ not an accountant.)

I calculated the scale factors for some new cars, using more measurements per car.
Here are the calculated 'scales' for the length, width, and height of each car. By averaging them I calculated a composite scale. 

Note, however, the height scales are inexact - I took measurements, and made an estimated adjustment to get a figure for what the car would be with standard T-jet small wheels and tires, with the convertible top up, or whatever. But because the height scale factor is inexact, the composite scale, which is partly based on it, is not as precise I would like.

*AC Cobra 289* Aur T-Jet 
_l-w-h:_ 1:61-1:57-1:61 ..... Comp.= 1:60

*Ferrari 250* Aur T-Jet 
_l-w-h:_ 1:70-1:68-1:65 ..... Comp.= 1:68

*Porsche 904* Aur T-Jet 
_l-w-h:_ 1:62-1:64-1:58 ..... Comp.= 1:61

*Ferrari Dino* Aur T-Jet 
_l-w-h:_ 1:65-1:67-1:60 ..... Comp.= 1:64

*DeTomaso Mangusta* Aur T-Jet 
_l-w-h:_ 1:63-1:68-1:57 ..... Comp.= 1:63

*67 Camaro* Aur T-Jet 
_l-w-h:_ 1:78-1:68-1:64 ..... Comp.= 1:70

*68 Firebird* JL T-Jet 
_l-w-h:_ 1:77-1:68-1:61 ..... Comp.= 1:68

*65 Mustang* JL T-Jet 
_l-w-h:_ 1:76-1:57-1:64 ..... Comp.= 1:65

*70 Mustang Boss* JL T-Jet 
_l-w-h:_ 1:68-1:67-1:66 ..... Comp.= 1:67

More to come...


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## AfxToo (Aug 29, 2003)

Your grade school arithmetic teacher is very proud right now.

This is actually quite interesting! I have always thought the JL 1970 Boss Mustang was a nicely proportioned model. Perhaps the closeness of the scaling dimensions is a decent indicator of how well perceived the overall model will be. We could probably define a "Wonky Ratio" for scale models, where the greater the disparity between the scales of the primary dimensions the greater the Wonky Ratio. 

At the end of the day however, the scale models still have to be pleasing and attractive regardless of their adherence to dimensional integrity or their wonky ratio.


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## slotcarman12078 (Oct 3, 2008)

Isn't there a velocity factor to help smooth out the inconsistencies as far as L/W/H? I mean a car going a scale 1000 MPH is going to appear distorted, right? :lol:


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## Dslot (Sep 2, 2007)

AfxToo said:


> Your grade school arithmetic teacher is very proud right now.


Chuckle. 


> This is actually quite interesting! I have always thought the JL 1970 Boss Mustang was a nicely proportioned model. Perhaps the closeness of the scaling dimensions is a decent indicator of how well perceived the overall model will be.


Just as the wildly discordant l-w-h scales of the '65 Mustang make it one of the goofiest of the T-Jets bodies. Umm, sorry - wonkiest.



> We could probably define a "Wonky Ratio" for scale models, where the greater the disparity between the scales of the primary dimensions the greater the Wonky Ratio.


Not a bad idea. 
W = Smax - Smin 
where W = Wonkitude, Smax = the largest of the dimensional scale factors, and Smin = the smallest of the dimensional scale factors. The larger the difference between the scale factors the more wonky the body looks. The '65 Mustang has a W of 19, nearly twice the Camaro's Wonkitude of 10, and almost ten times the Boss Mustang's W of 2.



> At the end of the day however, the scale models still have to be pleasing and attractive regardless of their adherence to dimensional integrity or their wonky ratio.


A principle sorely tested by the aforementioned '65 Ford Fugly.

-- D


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## Marko (Jul 11, 2002)

Great work, Dslot. That is a handy formula, thanks for doing the brain work!!


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## Dslot (Sep 2, 2007)

*Big Bruisers*

Here are the scales for HO-slot models of the bigger actual cars.

l-w-h = the calculated 'scales' for the length, width, and height of each car. By averaging them I calculated a composite scale (Comp.). 

W = Wonkitude (Difference between the largest and smallest dimensional scale factors).

Note: the height scales are inexact - I had to fudge an adjustment for what the car would be with standard T-jet small wheels and tires, with the convertible top up, or whatever. But because the height scale factor is inexact, the composite scale, and the W, which are partly based on it, is not as precise I would like.


*Thunderbird 1960* Aur Vibe & T-Jet 
_l-w-h:_ 1:79-1:77-1:68 ..... Comp.= 1:74
W = 11

*Ford Galaxie XL500 1967* Aur T-Jet 
_l-w-h:_ 1:77-1:72-1:69 ..... Comp.= 1:73
W = 8

*Ford Galaxie 1963* Aur Vibe & T-Jet 
_l-w-h:_ 1:80-1:80-1:66 ..... Comp.= 1:75
W = 14

*Lincoln Zephyr 1940* Aur T-Jet 
_l-w-h:_ 1:81-1:65-1:77 ..... Comp.= 1:74
W = 16

*Chevrolet El Camino 1969* Aur T-Jet 
_l-w-h:_ 1:79-1:72-1:68 ..... Comp.= 1:73
W = 11

*Chevrolet Bel Aire 1962* JL/AW T-Jet 
_l-w-h:_ 1:74-1:71-1:68 ..... Comp.= 1:70
W = 6

*Chevrolet Chevelle SS* JL/AW T-Jet 
_l-w-h:_ 1:77-1:63-1:69 ..... Comp.= 1:71
W = 8

*Chevrolet Impala 1959* JL/AW T-Jet 
_l-w-h:_ 1:75-1:67-1:64 ..... Comp.= 1:69
W = 11

*Pontiac GTO 1969* JL/AW T-Jet 
_l-w-h:_ 1:72-1:68-1:65 ..... Comp.= 1:68
W = 7

*Pontiac GTO 1966* Model Motoring T-Jet 
_l-w-h:_ 1:79-1:69-1:62 ..... Comp.= 1:70
W = 17

*Dodge Charger 1968* Aurora T-Jet 
_l-w-h:_ 1:76-1:73-1:71 ..... Comp.= 1:73
W = 5

*Thoughts on Wonkitude:*

The '63 Galaxy does not look to me as if it deserves a W of 14. The problem is all in the height; L & W are spot-on. The body looks right, heightwise, but it is perched high on the frame, maybe to give tire clearance, or maybe because the posts were cast long to give the very hot vibe motors a bit more ventilation space. Still, it looks good to me, much better than that chubby '40 Lincoln that rates only two points higher on Wonkitude.

Wonkitude is supposed to be a quantification of how "wrong" or "off" the body proportions appears to the eye. It is calculated by subtracting the smallest scale factor (almost always Height) from the largest of the three scale factors. (Remember, a small scale factor means a LARGER scale: 1:77 is a smaller scale than 1:67 but 67 is a smaller scale factor than 77.)

The problem is that the scale ratio for Height is ambiguous on HO cars. The height of the body itself from the bottom of the rocker panel to the top of the roof, could be very much in scale with length and width, but once you set it on the tall chassis with clearance for the tires, the scale height of the whole package - track to roof - is suddenly much greater than the height of the actual car, ground to roof.

The Height of two models of the same car, measured from track surface to roof could be identical, but if the designer of one car tried to stretch the car body downward to give a more realistic visual ground clearance for the body, the car suddenly becomes much more disproportionate to the eye, even though the overall height (and therefore the W factor of the car) are the same. The early Atlas HO cars were examples of this kind of stretching and, boy, do they look funky compared to Aurora's. 

Also, since we are usually looking at the cars from above, the height is foreshortened, so it doesn't impact our judgment as much as if we were looking from a low angle. So it's looking as though we need a more complex formula for W that does not give height ratios the same weight as L:W proportion.

On the other hand, do we even need a Wonkitude number? Even if we can't quantify it mathematically, we all pretty much know it when we see it.

More to think about. 

Cheers,
-- D


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## ParkRNDL (Mar 20, 2002)

WOW. That Atlas/Aurora Tbird comparison really hits home. I LOVE the Aurora Tbird, but the Atlas... ewww. Very good point you make about the height throwing off the equation. It's a shame there's no place to readily get accurate numbers of the height from the rocker panels to the roof... but it's true, you just know wonky when you see it. 

One Aurora car that stands out to me as a particularly wonky one... the Mangusta. Google for pictures of the real thing, and you can see that it's a gorgeous, well-proportioned car. But the Tjet version... weird. length and width are probably okay, but just too tall all over the place. I'd love to see a correctly proportioned one in Tjet size, even if it had to ride high on the chassis...

--rick

edit: the wheelbase/overhang ratio is also a factor. best example I can think of is the AW '62 Chevy. aside from the roof/windshield being weirdly tall, the front and rear overhangs are WAY long. now don't get me wrong, I LOVE this car. I figured out a way to lower the windshield on the Impalas, anyway, and I think it looks great on the track. but it's one of those cars (along with the '59) that you can just about use to nerf people 2 lanes over...


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