Eee, to su bili dani. Nisam treba da kupujem benzin, ne treba registracija, policija te ne dira... Jedino sto cure bas nisu bile odusevljene kada bih im predlozio da se provozaju sa mnom.
Ali da ne davim previse...
Kod mene u selu ima jedna dugacka nizbrdica. Kada smo se spustali niz to brdo, otprilike do trecine brda smo ubrzavali. Posle toga smo se kretali istom brzinom. Da bi smo zeznuli to pravilo, morali smo da prebacimo u 'najvecu" brzinu i da okrecemo pedale. Jos ako se savijemo napred kao oni sto voze trke... Isli smo brze, ali ne onoliko koliko smo hteli.
Kasnije nam je profesor pricao da kad se vozis ka Beogradu i spustas se niz Bubanj potok, ako izbacis auto iz brzine, ubrzavace do neke brzine, i onda ce da se krece konstantnom brzinom.
Kada sam video ovaj dijagram, postalo mi je jasnije zasto.
Na ovom dijagramu je prikazano koliko snage treba uloziti da bi se savladali spoljasnji otpori, u zavisnosti od brzine vozila.
Da napomenem da su vrednosti brzina male a vrednosti otpora relativno veliki, jer je ovo dijagram za automobil.
Sada malo objasnjenje:
Isprekidana linija pokazuje snagu koja je potrebna za savladjivanje otpora pri kotrljanju (tockova po podlozi) u zavisnosti od brzine kretanja vozila. Ovde porast brzine ima znacajnu ulogu na povecanje ovih vrednosti.
Pri brzini od 20 km/h ima vrednost 0.7 kW.
Pri brzini od 80 km/h, vrednost je 3.5 kW.
Pri brzini 180 km/h, 15 kW se trosi za savladjivanje ovog otpora.
Tackasta linija pokazuje snagu koja je potrebna za savladjivanje otpora vazduha, u zavisnosti od brzine kretanja vozila. Ovde porast brzine ima veoma, veoma znacajnu ulogu na povecanje ovih vrednosti.
Pri brzini od 20 km/h ima zanemarljivu vrednost.
Pri brzini od 80 km/h, vrednost je 3.6 kW.
Pri brzini 180 km/h, cak 41 kW se trosi za savladjivanje ovog otpora.
I na kraju puna linija pokazuje zbir snaga potrebnih za savladjivanje otpora pri kotrljanju i otpora vazduha.
Pri brzini od 20 km/h ima vrednost 0,7 kW.
Pri brzini od 80 km/h, vrednost je 7,1 kW.
Pri brzini 180 km/h, 56 kW se trosi za savladjivanje ovih otpora.
Za ovo vozilo, kao zakljucak se moze izvesti sledece:
Pri veoma malim brzinama (do 20 km/h), otpor vazduha je zanemarljiv pa snaga se tada trosi na savladjivanje otpora kotrljanja. Do 80 km/h veci uticaj ima otpor kotrljanja. Preko 80 km/h otpor vazduha ima sve veci uticaj i sa porastom brzine raste deo snage vozila koji se trosi na savladjivanje otpora vazduha. Pri maksimalnoj brzini od 180 km/h, 15 kW ide na savladjivanje otpora kotrljanja, a 41 kW ide na savladjivanje otpora vazduha. Eto gde odose konji (ili Watti, ko sta voli).
Kod motora, oblik dijagrama je isti samo su vrednosti drugacije. Ali i tu otpor vazduha ima veoma znacajan uticaj.
Otpor pri kotrljanju je manji jer motor ima 2 tocka a ne 4 i gazna povrsina koja je u direktnom dodiru sa podlogom je manja (zbog ovalnog oblika pneumatika) od spomenutog vozila gde su pneumatici sirine 155 mm.
Otpor vazduha je manji pri gorepomenutim brzinama jer je ceona povrsina motora i vozaca dosta manja nego ceona povrsina automobila. Ali kod motora su brzine vece, pa gubici drasticno skacu. Sto je aerodinamika motora bolja, otpori su manji. Sto je vozac u polozaju da manje kvari aerodinamiku, ici ce brze.
I posle pitaju sto vozim motor sa oklopima. Kakvo pitanje. Pa zbog toga da mi ne budu mokre noge kada vozim po kisi.
Nadam se da sam uspeo da objasnim sta me je to mucilo kada sam bio klinac i zasto moj bajs nije hteo brze.
When I was a kid, my primary mode of transportation was Bajs (for those who do not know, it's a bike).
Eee, those were the days. I did not have to buy gas, do not need registration, the police have not touched ... The only thing that the girls were not exactly thrilled when I suggested they take a ride with me.
But not too much I'm drowning ...
With me in the village has a long downgrade. When we descended down the hill, about a third of the hill until we accelerate. After that we move the same speed. In order to zeznuli this policy, we had to move in the 'largest' speed and turn the pedals. More if you bend forward as those which drive the race ... we went fast, but not as much as we wanted.
Later we talked to a professor when you drive to Belgrade and go downhill, vehicle will accelerate to some speed, and then will be moving at a constant rate.
When I saw this chart, it became clear to me is why.
In this diagram shows how much power to be deposited in order to overcome the external resistance depending on the speed of the vehicle.
To note that the value of speed and low resistance value is relatively high, because this is a diagram of a car.
Now a little explaining:
Dotted line shows the power required to undertake the rolling resistance (the wheel base) depending on the speed of the vehicle. This growth rate has a significant role in the increase of value.
At a speed of 20 km / h has a value of 0.7 kW.
At a speed of 80 km / h, the value is 3.5 kW.
At a speed 180 km / h, 15 kW are spent to undertake this resistance.
The dotted line shows the power required to undertake the air resistance, depending on the speed of the vehicle. This growth rate is very, very important role in the increase of these values.
At a speed of 20 km / h has a negligible value.
At a speed of 80 km / h value is 3.6 kW.
At a speed 180 km / h, even 41 kW is spent to undertake this resistance.
In the end, the full line shows the sum of forces needed to undertake the rolling resistance and air resistance.
At a speed of 20 km / h has a value of 0.7 kW.
At a speed of 80 km / h, the value is 7.1 kW.
At a speed 180 km / h, 56 kW is spent to undertake such resistance.
For this vehicle, as a conclusion can be derived as follows:
At very low speeds (up to 20 km/h) has a greater influence rolling resistance. Over 80 km / h wind resistance is an increasing impact velocity increases with the increase of the strength of vehicles that are spent on the resistance against air resistance. At the maximum speed of 180 km / h, 15 kW goes to the resistance against rolling resistance, and 41 kW resistance against going to air resistance. That's where they went horse (or Watt, who is love).
In the Bike, the shape of the diagram is the same just different values. But the resistance has a significant impact.
Rolling resistance is lower because the engine has 2 wheels and not 4 and tread that is in direct contact with the ground is smaller (because of the oval-shaped tire) starting from the vehicle where the 155 mm wide tires.
Resistance is lower in the above-mentioned speed as the frontal area of engines and drivers a lot less than the frontal area of the car. But at higher engine speeds are so drastically jump losses. What is the engine better aerodynamics, less resistance. What is a driver in a position to less spoiled aerodynamics, will go fast.
And after asking that drive motor with armor. Questions. And for this reason that we are not wet your feet when you ride in the rain.
I hope I have managed to explain what bothered me was when I was a kid and why he did not want my Bajs faster.
PS: The text is also on the forum www.motorri.com
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