Main hoop Bracing support configuration

Carlzxcv,

Your grasp of the simplest racecar Mechanics is clearly lacking.

It is fairly well accepted in FS/FSAE that a Team choosing a small engine can more than compensate for the lack of power by having very high lateral acceleration. It is an approach that has worked well for many (Globally!) winning Teams.

But your lack of Mechanical commonsense is quite common.
~o0o~

What worries me more is this:

Quote:

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Originally Posted by Bemo

Option 3 is not rules compliant IMO. There is just no frame member going from the bracing attachment point to the lower part of the main hoop.

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Bemo,

In Option-3 there very obviously are "Frame Members*" that provide a "properly triangulated" load path from the "lower end of the Main Hoop Braces" down to the "node where the lower Side Impact Member attaches to the Main Hoop".

(* "NOTE: Each of the above members can be multiple or bent tubes provided the requirements of T3.5.5 are met.")

Not obvious???

Z

Quote:

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Originally Posted by Z

Carlzxcv,

Your grasp of the simplest racecar Mechanics is clearly lacking.

It is fairly well accepted in FS/FSAE that a Team choosing a small-engine can more than compensate for the lack of power by having very high lateral acceleration. It is an approach that has worked well for many (Globally!) winning Teams.

But your lack of Mechanical commonsense is quite common.
~o0o~

Z

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hello Mr. Z,

1)Agreed my grasp of race car dynamics and mechanics leave a lot to desire, may b that's why i am trying to work hard to get an average set-up car on its wheels so that i can go round and round in circle's and understand the so called mechanics better :).

2) The teams which you mentioned who have won competitions with small engines, according to my research have a power to weight ratio of 130-150 bhp/ton, whereas i only got 90 bhp/ton.

3) we do not have an aero package, and according to tire data given in avon tires website, The tires can only pull 2G's when they have a load of 150kg's on them (which will, for our car mean to ride on two wheels up in air, so that outer rear wheel will have 150 kgs load on them)

4) so can you please direct me as to where i am wrong in assuming 1.5G average cornering force for our car, but the design still having enough left to take on 2G's (provided the tires stick)

Carlzxcv,

You are digging yourself a deeper hole.

* "Bhp/ton" has NO influence on lateral acceleration capability.

* If Avon say their tyres "can only pull 2G's when they have a load of 150kg's on them", then how many "Gs" do you think those tyres will pull with a load of only 100 kg on them? Or 50 kg? Or 200 kg?

* If you design your car with an assumed working load of 1.5G but "still having enough left to take on 2G's", then you can expect many failures. Well, assuming you get said car built in the first place.

Z

Quote:

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Originally Posted by Z

Carlzxcv,

You are digging yourself a deeper hole.

* "Bhp/ton" has NO influence on lateral acceleration capability.

* If Avon say their tyres "can only pull 2G's when they have a load of 150kg's on them", then how many "Gs" do you think those tyres will pull with a load of only 100 kg on them? Or 50 kg? Or 200 kg?

* If you design your car with an assumed working load of 1.5G but "still having enough left to take on 2G's", then you can expect many failures. Well, assuming you get said car built in the first place.

Z

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Mr Z,
If digging a deeper hole results in me understanding some concepts better or get a new view point, I’ll gladly dig a hole every day.

1)The vehicle with more Bhp/ton will have a higher corner entry speed, provided the driver utilizes the car’s potential. Let’s compare two cars:

a) A 250 kg car equipped with Cbr 600rr engine, churning out 60 horses.
b) A 210 kg car having KTM 390 engine, giving a power output of 30 horses.

Which car do you think will have a higher cornering speed and thus greater lateral acceleration?

2)I do not have data for 50Kg’s but according to Avon, a 75kg vertical load can generate maximum force of 1250 N, a 150kg load will give a cornering force of 2300N (my apologies for mistaking a conversion and telling you it can pull 2G’s at 150 Kg's), 225Kg (2930N), 300Kg (3830N).

3)I never said I designed my car keeping a working load of 1.5G, I said I designed a car capable of taking a lateral load of 2G, but assume that the car would not reach that high value of Lateral acceleration. What makes you think that the car would not be built? (shall we wager :))

You're thinking about the cornering problem ack-basswards.

Imagine a Bugatti W16 in a geo metro (extremely large power, not great handling). Say the tires on the metro can let you ballpark handle 0.5G lateral. Would you go into a 10m radius turn at 120 MPH (~50 m/s) just because you have a giant engine? (Hint: A = V^2/r = 250 m/s^2 ~= 25G!)

Don't go farther without understanding this point...

Quote:

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Originally Posted by Adam Farabaugh

You're thinking about the cornering problem ack-basswards.

Imagine a Bugatti W16 in a geo metro (extremely large power, not great handling). Say the tires on the metro can let you ballpark handle 0.5G lateral. Would you go into a 10m radius turn at 120 MPH (~50 m/s) just because you have a giant engine? (Hint: A = V^2/r = 250 m/s^2 ~= 25G!)

Don't go farther without understanding this point...

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Hello Mr. Smarty pants,

You are my hero as you provided me with the perfect opportunity to present my point.

I completely agree with you on your example, the car will be an abomination to drive, let alone race with.

Now consider a BMW M3, arguably one of the best handling cars of the world. Present it to a team of best engineer's from all around the world, and then fit it with a 100cc motorbike engine.

will it corner at the G's it is designed for or will it crawl across the track?

Do not comment a single word further, without understanding this point.

carlzxcv,

You're being a bit of a jerk to people who are actually trying to help you.
In your example, there is absolutely no reason why the M3 wouldn't be able to pull the same lateral G's as it was designed for. In fact it may pull more (I imagine a 100cc engine will have less mass than the S55).

What you need to be concerned with is whether or not your '90hp/ton' is enough to accelerate your vehicle to about 50km/h and keep it near there on a FSAE track. Hint: it is.

hello Jay,

If a M3 with a 100cc engine can pull more lateral G's than it compared to its stock engine, Then I think you are right about me being a jerk and a jackass for not understanding one bit about vehicle dynamics. I guess time for me to give up chasing motor sporting and find a dumb desk job.

But as i am a jerk, one last pitch to prove my point:

I took a design spec sheet from google, and started calculating lateral weight transfer. Lets call this car A and our car as car B.

Car A:
Engine: Yamaha R6 (60Bhp)
wheel base: 5.5 Ft
wheel track(front): 4.08Ft
C.G. Height: 1Ft
Roll center to C.G.: 0.78 Ft
front roll center height: 0.22 Ft
rear roll center height: 0.24 Ft
Weight at front: 316lb
weight at rear: 386lb
Roll gradient: 4.6deg/G

Calculated Total lateral load transfer at 1.8 G: 90%

Car B:

Engine: KTM 390 (30Bhp)
wheel base: 5 Ft
wheel track(front): 4.265Ft
C.G. Height: 0.833Ft
Roll center to C.G.: 0.916 Ft
front roll center height: -0.083 Ft
rear roll center height: -0.083 Ft
Weight at front: 246lb
weight at rear: 370lb
Roll gradient: 1deg/G

Calculated Total lateral load transfer: 80%


Now consider a hairpin bend of radius 4m at the end of a 60m strech, Can you please tell which car will generate more cornering force.

Aadil,

When you are deep in the sh*t, the very first thing you need to do is STOP DIGGING.
You are adding nothing to your credibility with sarcasm.
It's time to stop squawking and start listening!

And as I have told you twice already, behave yourself!

Pat Clarke

Quote:

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Originally Posted by Pat Clarke

Aadil,

When you are deep in the sh*t, the very first thing you need to do is STOP DIGGING.
You are adding nothing to your credibility with sarcasm.
It's time to stop squawking and start listening!

And as I have told you twice already, behave yourself!

Pat Clarke

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okay sir,

Sorry you all are correct and i was wrong to put forth my point, without any concrete proof.

Thank you for your time, no offense meant :)