Design Process

[mohamedabolezz]

Hi,

We are first year team intending to participate in the formula student competition in the class 1 this year.

I have some questions considering how to start the design process.
Q1. Who should start at first?
Should we start it from inside out or should we start with the external appearance for the car and the to follow it by an ergonomic model and then the suspension team begins to put the geometry and to make the mounting points on the frame for the frame team to start from?
Q2. When Should we start with preparing the required documents to be sent to the completion, should we start with the vehicle design and after finishing we start preparing out documents or should it all work in parallel?

Q3. As a First year team, would it be hard to work on a monocoque frame?

Mohamed Abolezz
Helwan University, Egypt
HFS Racing Team | Team Captain

[Bemo]

Hi Mohamed,

First of all I'd advise you to read the complete thread "Reasoning your way through the FSAE design process" which is sticked to the top of this forum. It was started by Geoff Pearson who participated with the RMIT team and later he was involved in the competition as a faculty advisor. He shares some very good thoughts in this thread and also there is some very interesting discussion there where people from different teams and different parts of the world shared their views. As a beginner team this will give you some very useful insight in what this design process should be like.

For the rest I can only say that there is no order in which you design the car. All the parts have to be designed together to make a proper overall package and with your documents you cannot start early enough. This way you will realize if there are any issues with rules conformity of your chassis before you even start building it.

[Ahmad Rezq]

First of all I'd advise you to read the complete thread "Reasoning your way through the FSAE design process" which is sticked to the top of this forum. It was started by Geoff Pearson who participated with the RMIT team and later he was involved in the competition as a faculty advisor. He shares some very good thoughts in this thread and also there is some very interesting discussion there where people from different teams and different parts of the world shared their views. As a beginner team this will give you some very useful insight in what this design process should be like.

For some reason the first post in the mentioned thread ( Reasoning your way through the FSAE design process ) was deleted,
I found a pdf file contains the first post, you can downloaded from here
https://dl.dropboxusercontent.com/u/2583139/Reasoning_your_way_through_the_FSAE_design_process _fsaeforums_20150503.pdf

Mohamed,
Few tips which reflect my thoughts for Egyptian teams.

1 - Build a simple spaceframe, with almost the required tubes mentioned in the rules book, add some steel skins to reach the required stiffness.
2 - Don't give the suspension design more than it deserve, if you will use Double-wishbones, make it very simple, with direct acting. or you can think in the beam axles both front and rear.
3 - make the toe as stiff as possible,
4 - if you don't have the required fund use 13" wheels they are available in the local markets in Egypt.
5 - if you can find a good single cylinder engine, it will reduce many efforts in building the car.
6 - I didn't search myself for air-cooled engines in Egypt but if i were one year before i would try to consider them.
7 - we don't have manufacturing techniques in Egypt better than, Laser cut, Welding, Bending. try to consider them in the manufacturing for example, sheet-metal uprights will save your time,money as compared to machined uprights. brackets, pedals, whatever try to make them out of bending,welding and lathe.
8 - No aero, nose and side-panels will be good for your case.
---------
Consider finishing the car at least 3 month before the competition, test it, be on the track it's really sad that there is no Egyptian teams can drive the car on the track.

[mohamedabolezz]

Thanks Bemo for the reply,
Don't you think we should consider the dependencies of some tasks on others?
Won't that save some efforts and time?

[mohamedabolezz]

Hi Rizk,
At First, Thanks for your valuable Tips and i wish we meet soon :)

I read the full thread "Reasoning your way through the FSAE design process" a year ago.
It was a really go start to me. But i found it more considering the team roles and hierarchy, I Think i need to get more into details.

- Actually i need to get more into level 1 Details, Any suggestion for getting information for it ?
- Considering level 2 do you think books like Learn and compete and Tune to Win would work for it?
- Regarding the wheels we are already having the 13″FormulaKosmo rims, do thing smaller diameter would benifit?
- Our Previously built car in our college was using the cbr600rr and i think its all about building a good intake and a clean wirning harness, Don't you think so?
What benifits do you think we could get from single cylinder?
- Considering the 7th point you have mentioned using sheet uprights, Don't you think it would be very high unsprung mass compared to the Aluminium Alloy machined uprights?
- Point 8: Don't you think considering aerodynamics in sth like the radiator and rotors cooling would benifit in our case ?

[Freddie]

Thanks Bemo for the reply,
Don't you think we should consider the dependencies of some tasks on others?
Won't that save some efforts and time?

I'm not Bemo, but I would say that for the first year the best solution is to separate as much as possible.
Yes, the car will be heavier and have much less "elegant" solutions, but the main challenge in designing the first car is to realise _exactly how many systems and parts that go into a car_ (at least it was for us). You will forget something, and if everything is integrated late-stage modifications become very complex.


Hi Rizk,
- Considering the 7th point you have mentioned using sheet uprights, Don't you think it would be very high unsprung mass compared to the Aluminium Alloy machined uprights?
- Point 8: Don't you think considering aerodynamics in sth like the radiator and rotors cooling would benifit in our case ?

In my very humble opinion, do not bother too much about unsprung mass at the moment. Just make sure that you have a rolling car in time.
I think each corner on our first car was 6 kgs or more (yes, we got questions if we were running hub-mounted motors due to the size of the uprights and the fact that they were more or less a solid chunk of aluminum, no pockets or cutaways) since we had a shortage in FEA analysis competence and prioritized the frame. While being ridiculously heavy, the unsprung weight ceartainly wasn't our main issue. Not even top ten.
The cooling system we plumbed while being more or less sleep-depraved and burned out, on the other hand ...

Regarding the radiator: make a sidepod/radiator shroud that connects the radiator to the fan without any "cool" shapes or gaps. That is more or less enough, if you place it somewhat reasonably.

[mohamedabolezz]

I'm not Bemo, but I would say that for the first year the best solution is to separate as much as possible.
Yes, the car will be heavier and have much less "elegant" solutions, but the main challenge in designing the first car is to realise _exactly how many systems and parts that go into a car_ (at least it was for us). You will forget something, and if everything is integrated late-stage modifications become very complex.

Fredrik Henriksson,

Thanks for your considerations :)
Currently, I am woking on time plan using Gantt charts to map the design process and to get sure that all the parts will work together.
But I am not sure with the task dependencies, duration and if i am covering all the tasks for a final design ready for manufacturing or not.
And I need some one to check it for me.
https://www.dropbox.com/s/v5phlna2lvye86q/HFS%20Design%20process.pdf?dl=0


Thanks

[Ahmad Rezq]

Mohamed,

-Yes smaller would be a benefit, But if i were you i would use the 13" wheels your team have to save money.

-Some of the benefits for running single cylinder engines are, less weight, better weight distribution, simple intake design, simple exhaust(only a bent stainless steel pipe which you can make it yourself at the team workshop).

-It won't be very high unsprung mass, For example Kettering University 2015 uprights were fabricated from 4130 0.025" sheet and was 0.590 kg front and 0.545 kg rear. you can still make light and stiffer design out of sheet metals if you do it the right way, and In Egypt you will save TIME!

-I won't bother design side pods, for the radiators actually i would buy a good quality motorbike radiator, big enough, mount it at the rear of the car or maybe at the main hoop bracing and use a big fan, For the rotor you may need air if your brakes and wheel-package are very small, but with good brake design i think you can finish the endurance without any problems.

[Z]

Mohamed,

It seems you are starting at the top-left in the process path shown below, and you are going to work your way through the other stages.

If you and your team work very, very hard, then you just might make it to the bottom-centre stage by the time the competition starts.

https://lh4.googleusercontent.com/-SPkR9U8a6-o/ULF0hbYtjnI/AAAAAAAAAL0/ppEqpxUw7rY/s800/tree_swing_70s.jpg

Consider how much easier it would be for your team if you start at the bottom-right image.

In FS/FSAE terms, the bottom-right image is,
"A small car that can drive 30 km at an average speed of 50 kph."

Z

[mohamedabolezz]

Mohamed,

It seems you are starting at the top-left in the process path shown below, and you are going to work your way through the other stages.

If you and your team work very, very hard, then you just might make it to the bottom-centre stage by the time the competition starts.

In FS/FSAE terms, the bottom-right image is,
"A small car that can drive 30 km at an average speed of 50 kph."

Z

Hi Z,
So, How do you think should it be working like?
Starting it all together on the same time ?

[mohamedabolezz]

Mohamed,

-Yes smaller would be a benefit, But if i were you i would use the 13" wheels your team have to save money.

-Some of the benefits for running single cylinder engines are, less weight, better weight distribution, simple intake design, simple exhaust(only a bent stainless steel pipe which you can make it yourself at the team workshop).

-It won't be very high unsprung mass, For example Kettering University 2015 uprights were fabricated from 4130 0.025" sheet and was 0.590 kg front and 0.545 kg rear. you can still make light and stiffer design out of sheet metals if you do it the right way, and In Egypt you will save TIME!

-I won't bother design side pods, for the radiators actually i would buy a good quality motorbike radiator, big enough, mount it at the rear of the car or maybe at the main hoop bracing and use a big fan, For the rotor you may need air if your brakes and wheel-package are very small, but with good brake design i think you can finish the endurance without any problems.

Hi Rizk,
Do you suggest a good single cylinder engine that have suppliers in Egypt?

[Pat Clarke]

Mohamed,

You just don't understand what Z is trying to tell you! Take another look at the cartoon.

Meanwhile, get an engine...any engine that fits the rules. Otherwise you will still be looking for the 'perfect' engine when the competition arrives.

Pat

[mohamedabolezz]

Mohamed,

You just don't understand what Z is trying to tell you! Take another look at the cartoon.

Meanwhile, get an engine...any engine that fits the rules. Otherwise you will still be looking for the 'perfect' engine when the competition arrives.

Pat

Hello Mr Clarke,
Thanks for your response.

I took another look to the cartoon, I got what Mr Z is trying to figure out.
But, I'm Still confused how to start it all and to have the whole team working in harmony through the design different phases.

Thanks.

[Z]

Mohamed,

Just to be clear, the Tree-Swing starts out unnecessarily complicated at its very first stage. Does it really need the three seats shown in top-left sketch?

And from there things just get worse ... until finally you get to the bottom-centre sketch!

https://lh4.googleusercontent.com/-SPkR9U8a6-o/ULF0hbYtjnI/AAAAAAAAAL0/ppEqpxUw7rY/s800/tree_swing_70s.jpg
~o0o~

Getting back to your FS design, you have already indicated that you are considering a monocoque, "bellcranks" are in the suspension design, you have mentioned the biggest, most powerful engine you can think of, and that it needs a "good" intake system, and wiring harness, and so on.

Are all these things absolutely necessary to carry a single person a distance of 30 km, at an average speed of 50 kph?

Now think about how simple the bottom-right Tree-Swing sketch is, and how much fun you can have on such a swing.

Next try to think of the simplest possible FS car that you could design and build (... to carry one person 30 km at average speed of 50 kph), and how much fun you could have with it.
~o0o~

Here is the Aston University Build Thread 2015 (http://www.fsae.com/forums/showthread.php?11888-Vehicle-Dynamics-starting-points-and-design-process). This is a long thread, but just reading the first few pages will give you some good advice on "starting the design process".

(It is quite sad that the Aston-U-2015 campaign ended as it did. Christian and some of the other members of that Team seemed to be making good progress, until (apparently) their Supervisor scuttled their plans and made them go back to doing what they had always done. Namely, building a complete failure of a car. See FSUK-2015 results, with Aston getting zero dynamic points!)

Z