Dirty_Vinylpusher

That's ok.
Hope to see some progress soon.

And pictures.
Lots of pictures

Lars from Norway

Of course, that is why i always write theoretical speed, and it is very helpful to know that the car will be too heavy geared before you even start the build

wh1sp3r

Lars, about the size.

I bought a cheapest chainsaw possible with 25,4ccm .. it's only 800W. And of course, i don't want to give it more money into it becuase it's my first homemade car.
Also, i am not sure, if bigger car will be suitable for using my motor. if everything works as i wanted fine .. i will build more more larger car with more powerful motor
For first, it's just better to do more simplier things. It's easier to complete it

About theoretical calculations yes, you are right.actually, theory is important for me, becuase it provides an idea about speed, torque, how car will turn. i wish i have a diagram of my engine, hehe

Dirty_Vinylpusher

I think we've all agreed that anything higher than 6:1 is no good though?
Especially with chainsaw/weedie motors. as the clutch engages too soon.

Also, the faster you go, the harder you crash and the more you break....

Giorgos_cupra

Wisper,i know i have said this in the past,but i'll say it again....If you make the car without suspension and direct drive from one sprocket to another,meaning that there wont be any kind of differential effect,you wont care much about the ratios,torque,acceleration and finally speed.That's because you wont be able to drive and especially turn the car under high speed.

With no suspension you get almost zero handling and to make things worse the 100% locked diff,wont let you turn without the back end slipping out in EVERY corner!

In real 1/1 cars,we only tighten the rear diff to make the car oversteer more.Notice,i said tighten...Imagine that your car will have a 100% rear locked diff.

I'm saying all these for your own good.You are going to put a lot of work in that car....It's a same to be dissapointed at the end

wh1sp3r

Hello,

Giorgos_cupra, i agree and i understand. Of course, my car will have suspension, i design own. I have no idea, if my susspension will work, but i hope so.
It will be two shafts .. one whit diameter for example 10mm and second 5mm. In 10mm will be 5.05mm hole, where will be smaller shaft. It will contain vaseline as a material, which should absorb impacts + it will have a spring, which will return shafts into default position. if it's not working, fine .. i will buy oil suspensions.

Another thing is, where will be centre of mass.

It's not only about driving car fun is building and fighting with problems too. That's why i am building own car otherwise i can just buy it.


Also, new car size is 65cm long, 30 cm wide.
I attached a image, it's a aluminim plate as i promised yesterday.

So, time to turn milling machine on and create some piece of aluminim blocks

Giorgos_cupra

Thar's great news!I'm glad you decided to put suspension in your car!You are surely not going to regret it!

Give your own shocks a try,and if they don't work just by a set as you said.It's nice to try and make things your own,and if ends up not working,you at least had fun doing it and also learnt something

As for the center of mass-center of gravity(cog) it would be ideal to be 50-50.That's what i'm after on my own car,and because there is no space for the tank,i'll mount it above the brakes.I m building a drift car so cog is very important,that's why the uplifted tank mod...You shouldn't be so concerned as i am thought....A 40-50 will be fine,even a little more on the back to give better traction at rear wheels...

Chassis looks ok....What kind of aluminum did you use?
Here is mine...It's longer and narrower

wh1sp3r

I don't know, what kind of aluminium it is . i am glad, they have something it's 1.5mm thickness and i will use U profiles to make it stable (no bending)

Your profile looks very thin

Giorgos_cupra

Whisper 1.5mm is a little too thin...I wouldn't use it as a chassis.

My chassis is 5mm and the bearing blocks are 8mm

wh1sp3r

5mm ? i will compensate it with U profiles. Three in the middle in full length, where engine is mounted and one on each side.
This sheet is hard to bend, so with U profiles, it should be ok. we will see. I had this sheet for free, so no problem to change it later, if it will not be suitable.

Profile U size is 20x10x2

Dirty_Vinylpusher

I disagree.
This car had no diff and turned just fine.
Both on grass, sand and on the road.


[youtube]http://www.youtube.com/watch?v=JRYwSfxjcWk&feature=channel_video_title[/youtube]



That's what I always say too

wh1sp3r

What about brakes ? How do you solved it ?

Dirty_Vinylpusher

That one didn't have brakes.
I mostly ran it at the beach where there was less stuff to crash in to.

Lars From Norway built his own brakes on his project.
I'm sure he can find that picture faster than I can so maybe he'll post it up next time.


I'm working on a large car at the moment ( http://www.rcuniverse.com/forum/fb.asp?m=10257058 ) which will have disk brakes from a pocketbike/minimoto.




When you set up the steering you should apply the Ackerman principle.
The car will turn a lot better that way.

Lars from Norway

Yup, [link=http://www.rcuniverse.com/forum/m_7681456/mpage_1/key_/tm.htm]here[/link] is the link to my thread. Have a look at page 5 or 6, i think the work with the brakes starts there. I was not able to finish them off before i moved, but now i will soon be up and running with a new workshop.

Giorgos_cupra

I said under HIGH speed.Didn't see any of that on your video.Also,those big tires you have help a lot.Try an on road with only 12cm diameter tires,no suspension and no tires,and we'll talk again

Dirty_Vinylpusher

Yeah but he's building an off-road car...

Anyway.
Of course suspension and diff is always gonna be better, I'm not disputing that, but what I am saying is that a home made RC car will work ok without.
If you're only gonna use it to bash around the backyard, in the park or on the beach.
For on road racing around a track it's obviously different.

Giorgos_cupra

Yeah,i guess i got a bit carried away by my expirience,from which i ended up dissapointed.....

For off road you get much more traction from the bigger and wider tires...Also i'm looking forward to those vaseline shocks...I wanna see how they turn out...I have a bit of vaseline left from my helicopters dampeners

wh1sp3r

hehe, i don't know, if it will work well just a crazy idea .. but who not try nothing know

wh1sp3r

Hi, some news.

I haven'T recieved my sprockets yet, so i did only chassi and engine mount. i know it seems, engine is very high, but i will lower it about 2cm and it looks ok.

On photos, you can see a L profiles on alu sheet and now, it's really strong even my sheet has only 1,5 mm.
You can see my working place too, two drill machines and grinder, next room, i have lathe and milling machine

Next time, i hope, i will get sprockets, so i will place them on the chassi and i will make a alu block for bearing holders and will make shafts

Over weekend, i will try draw, how will final car look like

Stay tuned, hehe

Lars from Norway

Looks very promising so far I envy your workshop, looks like i could have fit in there very well But tomorrow i am finally going to start build my own little workshop, i have been without one for over half a year now so i am pretty eagerly to get it started!

wh1sp3r

still waiting on my order of sprockets .. they should send it tommorow

wh1sp3r

Idiots .. still waiting on my sprockets They told me, i should get it tommorow (really). I am waiting for sprockets 18 days !

wh1sp3r

some progress...

wh1sp3r

got bearings and doing bearing holders

lol, one bearing for 0.29€ outer diameter 30mm, inner 10mm width is 9mm, bearing holder has 10.

Lars from Norway

Starting to get there now! Nice bearing holders