Spy Shots

ohh what is this creature?

uh???

Dandy, you're da man!

Looking good already, can't wait to try it out. With a bit of fiddling on my side with the Atom they should fit well together (I hope).

Looks good
Isn't that a KTM X-Bow GT4?

I have the stock physics worked out, GT4 is only a few tweaks.

still some modelling left...but thought I'd take it out for a spin.

I wonder if it's a contender

Something is off with the ger ratios of the 4th and 5th gear. They are basically identical, but the with 5th being SHORTER than the 4th. Even if you would switch 5th and 4th it would still be too close.

It should be the same gearbox the Seat Leon Cupra has (or whatever is on offer from VW), but even on the Seat I can only find something with odd numbers....

I'll keep searching. In the meantime I could imagine that the 5th gear is something like 1.000 (being the middle between 1.09 and 0.91 for 4th and 6th).

EDIT: aaah crap. The VW Golf GTI (Mk V), several Skoda, Seat and everything other model I found using the 2.0 TFSI engine have the same gear ratios.

EDIT II: this is getting interesting: apparently, for the 2005 Audi TT quattro sport, they used a different final drive ratio for 5th and 6th gear (how?). At least in the 2005 models with the 1.8l. I know it sounds weird, but the rest of the ratios is identical: source:
Audi World thingy

i found some bottom hits on hsl, especially using kerbs (with just 2 wheels). Is this something due or not?

About acceleration, I like it. You can feel the power under this small 2 seats...

Tomte wrote:Something is off with the ger ratios of the 4th and 5th gear. They are basically identical, but the with 5th being SHORTER than the 4th. Even if you would switch 5th and 4th it would still be too close.

I saw that coming from light years away. I had prepared my best Arnold voice to say "it's not a typo" but I'm already proven wrong. Thanks for the URL, it must be the secondary drive reduction. I e-mailed KTM asking for the final drive ratio. It took them weeks to reply with the locking ratios (45% acceleration, 65% deceleration I think it was). I replied with an explanation then never heard back.
I made a guess as to final ratio based on top speed achieved using standard VAG ratios. (217-220km/h)
Then I figured out some advantages to having the gears this way! (Requires a lot of careful shifting.)

DonaemouS wrote:
i found some bottom hits on hsl, especially using kerbs (with just 2 wheels)

collision box requires a lift (looks like 9 cm from 0 - its modelled at ride height)

DANDY wrote:I e-mailed KTM asking for the final drive ratio.

wow DANDY. You are not an hobbiest, but a professional plugin maker!!!

At the time of the Cadillac XLR, i sent an email to Cadillac USA too, but never got an answer to my question...

DANDY wrote:... it must be the secondary drive reduction. I e-mailed KTM asking for the final drive ratio. ...
Then I figured out some advantages to having the gears this way! (Requires a lot of careful shifting.)

I just wonder how they did it. I mean, normally, the final drive is in the differential gears. But I wouldn't know how to implement two final drive ratios at that location. So I guess it's somewhere in the gearbox housing itself (which of course actually also houses the differential gears...)
Anyway, I made some tests with the data from the pdf, using a final drive ratio of 4.235 and reducing the 5th and 6th gear by the difference of the two final drive ratios (4.235 / 3.273 = 1.2939 ), giving me 0.857 and 0.703. This appears to be rather long. With this settings, the car can just about hold the speed in 6th, but not accelerate.

Right now, the X-Bow seems to be quite planted in corners, with a quick initial turn in. But it is also plaged by understeer, much like the Atom. I wonder if this is also a effect of the rearward CoG. It's good fun on Black Forest, where it lies much flatter than the Atom. Stiffer suspension with some downforce to help it I guess.

One of my tests is to see how fast a car can drive in circles (on full lock) with the traction control (instead of full throttle). I don't even know if this tells me anything, but the Radical and the Caterham can do about 65 to 70 kph before the traction control kicks in.
The X-Bow goes up to 135 and the Atom even up to 160 kph. I think this shows that the rear wheels keep traction long after the front wheels scream for help. But then again, I'm not sure if this actually helps any bit.

Tomte wrote:
I just wonder how they did it. I mean, normally, the final drive is in the differential gears. But I wouldn't know how to implement two final drive ratios at that location. So I guess it's somewhere in the gearbox housing itself (which of course actually also houses the differential gears...)

I only wonder why....
The url you sent references a 3-shaft gearbox.

Tomte wrote:
Anyway, I made some tests with the data from the pdf, using a final drive ratio of 4.235 and reducing the 5th and 6th gear by the difference of the two final drive ratios (4.235 / 3.273 = 1.2939 ), giving me 0.857 and 0.703. This appears to be rather long. With this settings, the car can just about hold the speed in 6th, but not accelerate.

I used a more complicated method to come up with the same result.
The effect is worsened by my corrected (higher) air resistance.

Here it is with corrected gears, air resistance and collision box

I tried the car last night and though it was great fun. Was going to ask about 4th/5th Im getting much slower times than atom on lime. Car is very steady I find... fun to drive.. but kills if you touch grass.... kinda radical I guess.
Will check out second WIP since anything with the first might be all different now.

No wonder were not seeing you much on the track D... just one after another isnt it.
----------------------
EDIT:
SECOND RELEASE: I find this car, as the Atom, much fun to drive. I'm only trying it on lime to have quick reference and comparison. New release 5th gear seems really long now, but much better than 4th/5th twins of before. I still find the car much slower than Atom. I'm 4 seconds faster on lime with Atom. That's when I'm getting a clean lap with XBOW. I often crash from oversteer on downhill. I can manage pretty well on the rest of the track but the downhill makes me sweat as I approach in this car. Really easy to lose it there.

DISCLAIMER: these opinions are meant to be from someone who knows nothing about cars or physics but only meant as opinion from someone who loves to play redline.

here the evaluation for this new build. In first no bottom hits on entire Rocky Pass track.

Rocky Pass in 2:08'88
WALT Turn @ 165Kmph
U Turn Top Speed @ 205Kmph
90 Degree Turns @ 140kmph
E Turn @ 210Kmph

In WALT Turn, the car lost weight, as all cars, but remaim well steady on track, the car suffer a bit on oversteering. Approaching the U Turn this monster is incredibly fast, braking is not perfect, but madness. Just press brakes, change gear, change gear, turn, release, full throttle... WOW!

In 90 Degree turns the gearbox show its strenght. You can also using full throttle in second gear during entrance, the car spin, but get stable in less then a second.

Now, going down through the fastest turns and braking while turn. I have no word. Steady, solid, stable, full throttle in third gear, the Xbow spin, release, and the full throttle again...

DonaemouS wrote:here the evaluation for this new build. In first no bottom hits on entire Rocky Pass track.

Rocky Pass in 2:08'88
WALT Turn @ 165Kmph
U Turn Top Speed @ 205Kmph
90 Degree Turns @ 140kmph
E Turn @ 210Kmph

I'm not sure it is known to the others which turns you are talking about. Still, impressive numbers. Oh, I forgot, I put up our engineering drawing onto the ASW.

very fun car DANDY. makes for some really great racing. thanks

WHO ARE YOU PEOPLE?!?! WHERE AM I?

DANDY wrote:I wonder if it's a contender

I tried to make the X-Bow a bit quicker by massaging the torqueRPM (you have quite a range to play with), but to no avail up to now. Cannot better your settings. Though I would probably set clutchRPM to something like 2000.
In the same time I try to make the Atom slower and more dificult to drive. No huge success either.
Looks like I need to look into frontAirResisance for the Atom. But according to the published specs the Atom has an advantage in top speed... I had just hoped the X-Bow could use it's downforce settings to match the Atom's abilities around the track, despite the weight differences. The X-Bow has also more torque, albeit at lower rpm (good in town, bad on the track).

Tomte wrote:

DANDY wrote:I wonder if it's a contender

I tried to make the X-Bow a bit quicker

I think the speed is OK, given the air resistance. It accelerates quickly off the mark, probably hitting its published acceleration numbers. It does 226 in 5th gear at Bonneville, 6th will hold 216, while 217 is its published top speed.

I've softened the spring rate a little, which seems to help the turn-in, to the point where you still have to work it through the corner, but with improved road feel.

Just a few details left to go....

Here's an engine sound for ya:
AudiTT @ 7000rpm (350kB)
It doesn't have the same exhaust timbre as the X-Bow, but it's the same engine and sounds close enough in all other respects.

...and a better turbo sound than Redline's default blower-esque sound:
Same turbo that I used for the Ford RS200 Evo 2 (150kB)

And some engine sound settings. According to Tiff Needell in his Fifth Gear review, the engine was inaudible at higher speeds, and sounded muted and dull:

engineSample "C14ru5-Forza2AudiTT-7000rpm.wav"
hallSample "C14ru5-Forza2AudiTT-7000rpm.wav"
turboSample "C14ru5-Turbo.wav"
zeroRPMSoundGain 1.0
fullRPMSoundGain 1.5
zeroThrottleSoundGain 0.9
fullThrottleSoundGain 1.0
zeroRPMSoundPitch 0.13
fullRPMSoundPitch 1.0
zeroThrottleSoundPitch 0.9
fullThrottleSoundPitch 1.0
turboGain 0.1

In the Fifth Gear review, they also said that KTM had planned a 300HP version next year. Sounds interesting...

C14ru5 wrote:Here's an engine sound for ya

Thanks! Itchy fingers....


...got the best of me

Tasty, very tasty! That must be one of the best looking gear shifters we have! I like all the detailing, the lights, mudguards and so on! Great!

The engine sounds very creamy, but I can't really hear if I'm on the throttle or not.
I like the handling of the car. Not too safe, even on Lime Rock you can get into trouble at the uphill and downhill section. Quite planted.
It takes the bumps on Mountainside very well, much better than the Atom. It is also able to get a corner when I already thought it would succumb to understeer.

One thing though: you have different wheel.grip settings for the left and the right wheels (9 vs. 10). I don't think it makes a lot of difference though.

Tomte wrote:I can't really hear if I'm on the throttle or not

Oops, a small oversight from my part when I wrote my code example above. You should probably set zeroThrottleSoundGain to 0.5. It also doesn't help that zeroThrottleSoundPitch is higher than fullThrottleSoundPitch - the human ear foolishly thinks small changes in pitch correspond to similar changes in amplitude.

I also think this car handles very much like I would expect it to. Perhaps move both driver and steering wheel a bit forward, and increase the size of the steering wheel to maybe 0.15?

Tomte wrote:Tasty, very tasty! That must be one of the best looking gear shifters we have! I like all the detailing, the lights, mudguards and so on! Great!
It takes the bumps on Mountainside very well. It is also able to get a corner when I already thought it would succumb to understeer.

I think there's an RL first in there for those with keen eyes...I didn't think the shifter was all that great either....and the prominent handbrake is missing..I may still add it.
I set the suspension after testing on the mountain...it's just able to negotiate the bumps. I'd say its nailed in the 'pulling it out' department

Tomte wrote:One thing though: you have different wheel.grip settings for the left and the right wheels (9 vs. 10). I don't think it makes a lot of difference though.

That's what Betas are for.

C14ru5 wrote:

Tomte wrote:I can't really hear if I'm on the throttle or not

Oops, a small oversight from my part when I wrote my code example above. You should probably set zeroThrottleSoundGain to 0.5. It also doesn't help that zeroThrottleSoundPitch is higher than fullThrottleSoundPitch - the human ear foolishly thinks small changes in pitch correspond to similar changes in amplitude.
Perhaps move both driver and steering wheel a bit forward, and increase the size of the steering wheel to maybe 0.15?

My sound edits were very quick and off the cuff. I'm finding though that having zeroThrottlePitch set slightly higher than fullThrottlePitch simulates engine load.

Custom steering wheel's on the list.