OTK TonyKart M7 Nassau Discussion

I think the best way to battle that is to be objective. But us racers can be a tad selective about where we place our objectivity :grin:

Trolling is strong from TopKart today



Purely speculative aero here but asssuming a large proportion of the drag is air hitting the driver flat in the face (as per pic)

Then it might not be the cut out that’s the important bit. The cut out may be there to facilitate the flick up at the top part of the panel (where the tonykart triangle is). By doing this you are creating an upward airstream pushing the oncoming air around the chest and helmet of the driver creating a boundary layer around the driver potentially decreasing this large piece of drag.

Basically along the lines of the USA “big noses” along the lines of “punch a hole in the air and drive through”

The only thing about that is it doesn’t seem like the flow off of that “dip thing” would be quite wide enough?


I’m no aerodynamissisisisist but looking at Nik’s picture, it seems you really only need to skirt around that ~3" wide red part on the driver’s helmet, so I would guess the tunnel on the nassau would be wide enough to flick air over, and the sides of the panel would distribute it around.

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On that note, there’s a couple of studies on aero for karts for people to geek out on here:

Any pictures of the rest of the kart? Anytime we’ve done something “obvious” like this, it’s generally to catch eyes away from something else we’re testing or trying…

Either way, fascinating, I’d love to test that and see how it works.

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A more interesting way would be to have a scoop at the bottom of the nassau panel and an internal channel that led to a horizontal slit across the top of the nassau panel. I think this would achieve the effect more efficiently.

You are trying to achieve a faux Coanda effect effectively. The way OTK have done it is probably cheaper to manufacturer but less efficient.

So, according to this model…short people have less resistance!

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I would think that the most drag on a kart would be the vacuum created behind the driver and seat?


When you can do something to decrease the frontal area, drag or both it can help.

So generally shorter people will sit lower in the kart. It can depend on the seat being used, amount of tilt and so on. It can help, but then when you look at the build of someone like Simas Juodvirsis who put on a stellar performance at the supernats in 2012… it’s hard to know for sure.

The point of the new bodywork is to reduce frontal area, and streamline flow over the largest obstruction, the driver. In karting, reducing the drag coefficient will save lap time, no debate about that, but the question is how much.

After racing bicycles for years, where you are the engine, and aero is the single largest energy saver, YES, AERO MATTERS, at all speeds, and grows exponentially with speed.

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I mean, it could be worse.




Ardigo smoked them and I didn’t realize how fast they are really going in KZ over there. No doubt the nose and nassau help in KZ, in Europe. 206 and TaG in the US, probably not so much.


For what it’s worth, I’ve done a lot of aero stuff through the last year or so and making sure to do the best I can to make it pay off. I calculate aeropower in Racestudio since it weighs so heavily into a calculated dyno calculation. It’s also useful because if you see that all of the sudden your power output increases at a similar proportion to your supposed aeroHP increasing you can see that drag isn’t as big as you thought. It’s a great draft detector and cuts out some of the BS when looking at flyer laps espeically from mutliple drivers when I can’t remember every single straightaway pull of every single session.

Anyways, to put it into perspective for you just how big of an influence aero is, in a mini kart (not even a full size kart) with an average lap speed of 68.2 [km/h] and a minimum and maximum of 38.5[km/h] and 92 [km/h] has a lap average Aero power of 2.41 [hp] and a max of 5.27 [hp]. To put this in perspective since a lot of dyno results are skewed, 13.7 [hp] is considered max output with these calculations. This is the range I use for all of my simulation stuff and it seems pretty spot on. Granted some dynos will read higher than others, but instant output measures overall vehicle power and not engine output, so it takes rolling resistence and drag into account. To quantify that, on a sub-60 [mph] track in a mini kart, the drag averages around 17.5% of max output. That’s a lot. The theory that karts aren’t fast enough for aero just isn’t true from a drag perspective. We aren’t necessarily fast enough to produce effective downforce but that is an entire other can of worms with a lot of other factors.

I threw it through a quick lap simulation just for giggles - a 10% reduction in drag coefficient (a lot but not unheard-of) is worth around 3 tenths at Ocala in a mini (which is a relatively slow track with near-no straights) even before changing gear ratio and without considering that it can be accompanied with a change in frontal area. I’ll throw one in for New Castle if I get a chance later - I only have the Ocala model on my laptop and the rest are at home. Pretty insane - it’s clear why the people at OTK are pursuing it.

As Newey talked about in his book “How to Build a Car” (highly reccomend it, here’s a link: http://a.co/idiRzTg), he never wanted to focus on aero. It was just the only thing that made that big of a difference. Unless you’re able to build and develop your own tires and aren’t confined to a spec engine formula, the only thing that you have enough freedom to really find a massive technical advantage in is aero.

In before we see a new Tillet T1776t seat -> they might need to make a call to us over here across the pond to get the mold though… :upside_down_face:


Canned correlation /=/ causation statement goes here :smile: There was (maybe?) a bunch of the hot dog bun nassaus buried in the field too and that’s the crux of what I’m getting at.

Racing (well sport) is about psychology as much as anything else right? Driver sees other driver win and sees something obviously different, concludes it was a contributing factor.
Alternative fuel routing system, motor builder sticker, ceramic axle bearings, fancy anodised head on the motor etc etc. The challenge is separating the real determining factors and throwing away the rest.

Aero certainly makes a difference as @PosiMo_Andy put in great detail. While the average speeds of karts are (generally) low, the drag/power ratio is very high (Ok except laydowns).

CIK bodied karts have a large frontal area and massively poor CoD. So there are advantages to be gained, but there’s also dimension limits on the bodywork so any solutions have to work within those constraints.

Does this “hot dog bun” thing actually improve things, that is the question. I’m finding it hard to see it as probable.

Will it sell? No question there. People saw it on Ardigo’s kart and he won with it on there, so people will buy it.

One of the easiest aero things you can do and it doesnt cost a penny: Get your shoulders down and knees up. When I did some calcs a few years ago I found even an inch would reduce the frontal area by quite a bit.

Of course, getting down like that that presents comfort and chassis tuning challenges.

That’s what Dismore does on the straights at New Castle, as opposed to the front tuck everyone else does. I would imagine he would know what works best there.

Brilliant stuff @PosiMo_Andy, super interesting!

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Clearly they need to do away with front tires. Those appear to make the most drag.


Well they sort of have, they’ve made the nose cone wide enough to cover the front tires and direct the air around that positive pressure area.