Radiator Design For Forumla Student Project
Discussion
Hey guys, new member I know, hello everyone! Sorry if this is the wrong forum already but here goes.......
Basically the reason I joined is that I am a 4th year University student and we are currentley working on a Formula Student Project, the details about it can be found at www.imeche.org.uk/formulastudent/ .
My problem, I have a shed load of work on at the moment (final year projects, exams etc) and cant devote the car all the time I need. However I have been assigned the task of designing the radiator and cooling system for the car.
Basically it is powered by a 80bhp (60KW) motorbike engine, and will run around the track with an average speed we reckon on 40mph. We have been through cooling pump selection, and chosen to run it off the battery to save the small ammount of power we have for the poor wheels! Selected pump has a flow rate of 0.185kg a sec, seems pretty good selected it from demon tweaks. The next problem though is radiator selection and budget, we have about 2 grand for the whole car (but have most parts already so dont worry too much about that). So really I need to find the most effective, cheap, lowest drag inducing radiator for this car that wont cause it to overheat and explode as I have been told some have done in the past! Any help woulde be incredibly gratefully recieved, even if its just telling me to go to hell asking you lot this!
Thanks again
Richard Newcombe
University of Nottingham Formula Student Team
Basically the reason I joined is that I am a 4th year University student and we are currentley working on a Formula Student Project, the details about it can be found at www.imeche.org.uk/formulastudent/ .
My problem, I have a shed load of work on at the moment (final year projects, exams etc) and cant devote the car all the time I need. However I have been assigned the task of designing the radiator and cooling system for the car.
Basically it is powered by a 80bhp (60KW) motorbike engine, and will run around the track with an average speed we reckon on 40mph. We have been through cooling pump selection, and chosen to run it off the battery to save the small ammount of power we have for the poor wheels! Selected pump has a flow rate of 0.185kg a sec, seems pretty good selected it from demon tweaks. The next problem though is radiator selection and budget, we have about 2 grand for the whole car (but have most parts already so dont worry too much about that). So really I need to find the most effective, cheap, lowest drag inducing radiator for this car that wont cause it to overheat and explode as I have been told some have done in the past! Any help woulde be incredibly gratefully recieved, even if its just telling me to go to hell asking you lot this!
Thanks again
Richard Newcombe
University of Nottingham Formula Student Team
Had it been me I would have used the original engine water pump and radiator, reason being that all the R+D has already been done, it's all properley engineered and there are fewer items to fail.
Your now in the position that unless you plan to charge the battery between every race you will have to run an alternator to charge the battery, you will have to carry a hefty battery in the car where as a bike battery would probably have done otherwise, you have an electrical system to fail due to wiring or pump seizure etc. and that all assumes the design is up to the job, the benefit of power saving is probably negated or even overtaken by the negative of the battery weight and drag off alternator.
To use Colin Chapmans advice......
Simplicate, then add lightness.
Make the suspension adjustable and they will adjust it wrong -- look what they can do to a Weber carburetor in just a few moments of stupidity with a screwdriver.
To add speed, add lightness.
Your now in the position that unless you plan to charge the battery between every race you will have to run an alternator to charge the battery, you will have to carry a hefty battery in the car where as a bike battery would probably have done otherwise, you have an electrical system to fail due to wiring or pump seizure etc. and that all assumes the design is up to the job, the benefit of power saving is probably negated or even overtaken by the negative of the battery weight and drag off alternator.
To use Colin Chapmans advice......
Simplicate, then add lightness.
Make the suspension adjustable and they will adjust it wrong -- look what they can do to a Weber carburetor in just a few moments of stupidity with a screwdriver.
To add speed, add lightness.
In principle I'd agree with Oliver on this. What engine are we talking about? I would guess an old CBR 600. On that basis, the radiator on the bike is up to the job while being behind the front wheel and the airflow through it is restricted by the engine and fairing behind it. If you used the same parts, with the radiator placed a foot behind your head for example, that should be plenty good enough I would have thought...
So really I need to find the most effective, cheap, lowest drag inducing radiator for this car that wont cause it to overheat and explode as I have been told some have done in the past!
The mrk 1 Mr2 has the rad in the front of the car and the engine in the back. No trick rad and cooling required in the mr2 as the water /coolant cools on its journey from the the rear of the car to the front and back again. The coolant, i guess, cools in the pipework on its journey from front to back, if that makes any sense.
that is my understanding.
The mrk 1 Mr2 has the rad in the front of the car and the engine in the back. No trick rad and cooling required in the mr2 as the water /coolant cools on its journey from the the rear of the car to the front and back again. The coolant, i guess, cools in the pipework on its journey from front to back, if that makes any sense.
that is my understanding.
Edited by benzo on Tuesday 9th January 23:48
Remember this is an engineering job and not a science job, so you shouldn't be designing this thing from first principles. I'm not suggesting for a second that you should copy a design (they would quickly pick up on that) but there is no point re-inventing the wheel. So your first step should be to find out as much as you can about the previous entries (particularly the winners!). Not just what worked but what failed too. Also, as soon as possible, talk to your chassis and bodywork designers. They may already have made assumptions as to where the rad(s) will or will not go and thus impact on the dimensions.
I'm not convinced about the electric water pump. Unless it is lighter than the mechanical one, and proven in that application, I would go with the mechanical. Maybe leave it as a possibility for later, but as time is limited then I would be looking to simplify things. Simple is good. Fewer things to go wrong, and more time to make improvements rather than running round like a headless chicken just trying to get it to work at all.
This looks interesting: http://fsae.com/eve/forums/a/tpc/f/12
I'd kill (well, perhaps slightly inconvenience a couple of people) to be doing that project
Mike.
I'm not convinced about the electric water pump. Unless it is lighter than the mechanical one, and proven in that application, I would go with the mechanical. Maybe leave it as a possibility for later, but as time is limited then I would be looking to simplify things. Simple is good. Fewer things to go wrong, and more time to make improvements rather than running round like a headless chicken just trying to get it to work at all.
This looks interesting: http://fsae.com/eve/forums/a/tpc/f/12
I'd kill (well, perhaps slightly inconvenience a couple of people) to be doing that project
Mike.
wildoliver said:
Had it been me I would have used the original engine water pump and radiator, reason being that all the R+D has already been done, it's all properly engineered and there are fewer items to fail.
I couldn't agree more.
Get a refund on what has been bought from Demon Tweeks and put it towards lighter wheels.
Yeay, another Nottingham Uni bod!
There's some good stuff on the web at (I think) Exeter Uni about rad fitment for racing applications. Remember to mount it on an angle to increase the amount of water per m^2 of air you can cool - the site has some pointers for optimal angle useage. That way you can use smaller rads for the same cooling rate as a larger rad mounted vertially. Also don't try to cool the water too much - I doubt you'll get to this problem but running an engine too cold will result in power output drop.
I'll try to dig up the URL for you.
There's some good stuff on the web at (I think) Exeter Uni about rad fitment for racing applications. Remember to mount it on an angle to increase the amount of water per m^2 of air you can cool - the site has some pointers for optimal angle useage. That way you can use smaller rads for the same cooling rate as a larger rad mounted vertially. Also don't try to cool the water too much - I doubt you'll get to this problem but running an engine too cold will result in power output drop.
I'll try to dig up the URL for you.
GavinPearson said:
wildoliver said:
Had it been me I would have used the original engine water pump and radiator, reason being that all the R+D has already been done, it's all properly engineered and there are fewer items to fail.
I couldn't agree more.
Get a refund on what has been bought from Demon Tweeks and put it towards lighter wheels.
Well said that man, look up unsprung weight, you will be amazed the difference it makes especially on a lightweight race car.
Agree with previous posters that the electric water pump is basically waste of money. Bike pumps aren't big so shouldn't lose much power, plus also keeps things simple.
As mentioned, rad from same bike as engine should do if you can get one, though some bike bits can cost silly money.
Possible alternative might be rad from old Mini. Not massive, cheap and easily available from scrapyards and could be mounted flat in nose or at angle in side pod (depending on your design) to reduce drag.
As mentioned, rad from same bike as engine should do if you can get one, though some bike bits can cost silly money.
Possible alternative might be rad from old Mini. Not massive, cheap and easily available from scrapyards and could be mounted flat in nose or at angle in side pod (depending on your design) to reduce drag.
Could of links - I can't find the tutorial from the girl I was on about before, but this has some or the diagrams I remeber being used (near the bottom about getting air to the rad:
www.stockcarracing.com/techarticles/general/scrp_0509_efficient_cooling_radiator/
...
I'm having a lot of trouble finding the article on how to angle the radiator to get better cooling efficeny from it though. I'll have another look at lunch as my boss is harrassing me to work
www.stockcarracing.com/techarticles/general/scrp_0509_efficient_cooling_radiator/
...
I'm having a lot of trouble finding the article on how to angle the radiator to get better cooling efficeny from it though. I'll have another look at lunch as my boss is harrassing me to work
EWP is a gamble, and if you're planning to use one of those Davies Craig pumps that DT sell it's not a good one - they aren't cheap either. I would advise you to stick with the OEM cooling system, or as close as possible. Pay particular attention to details like the external circuit - bypass, degass circuit and so on are critical to reliable operation. Remember the physical geometry matters as well as the logical connections. Design the ducting to give good air convection through the radiator so you get some cooling while you're in the pits and while you're waiting on the grid.
From the digging around I did, at least 1 team mounted their rad horizontally at the rear of the engine. That will very much depend on chassis and suspension design though, and may limit the future suspension mounting points. All the teams (whose details I could see) were using electric cooling fans anyway, so they don't appear to be limited by weight. Some competition rounds do appear to take place in hot countries in summer, so excess capacity is probably a good thing. Looking at other teams, the budgets seem more than sufficient for full custom racing items, I don't know if all teams have the same budget.
Zad said:
From the digging around I did, at least 1 team mounted their rad horizontally at the rear of the engine. That will very much depend on chassis and suspension design though, and may limit the future suspension mounting points. All the teams (whose details I could see) were using electric cooling fans anyway, so they don't appear to be limited by weight. Some competition rounds do appear to take place in hot countries in summer, so excess capacity is probably a good thing. Looking at other teams, the budgets seem more than sufficient for full custom racing items, I don't know if all teams have the same budget.
The question is though - do you actually need a cooling fan? If the car is not going to idle except to warm up, and the radiator has sufficient capacity, because it is the one that came off the bike in the first place, then you might as well not bother. Similarly for instrumentation, the focus should be on trying to not put it on - you need an oil light, rev counter and NOTHING else.
There is so much wasted effort and money going into these projects that it's just ridiculous, keeping things very simple with a very good set up for chassis & gearing, competent driver and well chosen tyres and you could totally obliterate the competition.
Good rad for small race cars other than the original bike one is the VW Polo one, reasonable price from ECP or GSF & small & alloy & plastic. Can have leccy fan if needed!
Much too much effort going into these in the wrong places from what I see, what happens when you have students with no common or commercial sense I suppose!
Can we enter a PH team please!
Much too much effort going into these in the wrong places from what I see, what happens when you have students with no common or commercial sense I suppose!
Can we enter a PH team please!
Edited by tr7v8 on Thursday 11th January 11:37
One aspect on the video was the static judging where you will have to convince the judge (in the role of potential manufacturer of the car) that the car can be built to a price (amongst other things). This is a very good reason for you to use everything that comes with the engine and raid car manufacturers parts bins wherever possible. Any part your team design themselves will be many times the cost of a similar OEM part.
For your specific radiator query I would use a small car rad (Polo mentioned earlier) as it will be cheaper than the bike version. Mount it at, or close to, the back to keep the pipe runs short because all that water and pipe is unwanted weight. Design it so that a self contained fan & battery unit can be sat in place whilst working in the pits or waiting to make your runs and removed when racing. Formula 1 teams do this and also add dry ice. Make sure the header tank is the highest point on the system and any other high points either have bleed pipes back to the header or have bleed valves. Do not remove the thermostat. Many fall into the trap of thinking this will increase flow and cooling. What it will do is leave the engine running too hot or too cold dependant on the available airflow and make it impossible for the engine people to achieve any consistent tune.
Steve
For your specific radiator query I would use a small car rad (Polo mentioned earlier) as it will be cheaper than the bike version. Mount it at, or close to, the back to keep the pipe runs short because all that water and pipe is unwanted weight. Design it so that a self contained fan & battery unit can be sat in place whilst working in the pits or waiting to make your runs and removed when racing. Formula 1 teams do this and also add dry ice. Make sure the header tank is the highest point on the system and any other high points either have bleed pipes back to the header or have bleed valves. Do not remove the thermostat. Many fall into the trap of thinking this will increase flow and cooling. What it will do is leave the engine running too hot or too cold dependant on the available airflow and make it impossible for the engine people to achieve any consistent tune.
Steve
Wow cheers guys, some really good results there! Ive taken down a load of the links and am trying to sift through them in my spare time, got a few exams next week so that might not mean that I get to far with this right now, but once all my exams are done I shall get stuck right in.
One or two questions I have mind, So you believe that keeping the stock pump is better? We discussed this at length, and the problem is that we HAVE to keep a standard battery on board the car at all times, and currently it is pretty much just dead wieght. The idea was remove the pump from the engine saves a few horse power and a few pounds which cant be too bad? And then utilise that dead weight which we have to carry anyway. However all your advice seems to be pointing against this idea, so taking heed I will bring up your points at our next group meeting and make the guys listen!
Also I am lucky enough to have a tutor who used to work for williams F1 and the Jaguar LeMans Team (as he keeps telling me!) so has a fair bit of knowledge on the aerodynamic side of designing the radiator. His ideas are as you say to place the radiator in the airstream at an angle (reaserch from the past recomends 23.75 degrees as optimal) to reduce Cd relative to cooling effectivness etc. Is this what you meant when you mentioned angleing the rad?
Any more tips still gratefully recieved!
One or two questions I have mind, So you believe that keeping the stock pump is better? We discussed this at length, and the problem is that we HAVE to keep a standard battery on board the car at all times, and currently it is pretty much just dead wieght. The idea was remove the pump from the engine saves a few horse power and a few pounds which cant be too bad? And then utilise that dead weight which we have to carry anyway. However all your advice seems to be pointing against this idea, so taking heed I will bring up your points at our next group meeting and make the guys listen!
Also I am lucky enough to have a tutor who used to work for williams F1 and the Jaguar LeMans Team (as he keeps telling me!) so has a fair bit of knowledge on the aerodynamic side of designing the radiator. His ideas are as you say to place the radiator in the airstream at an angle (reaserch from the past recomends 23.75 degrees as optimal) to reduce Cd relative to cooling effectivness etc. Is this what you meant when you mentioned angleing the rad?
Any more tips still gratefully recieved!
Kiss principles? longer / thinner hose runs drain power, use gravity to induce flow (warm rises / cold falls). Water is also quite heavy in itself so calculate a design minimum for thermal mass transfer required (not neccessarily the potential output of the engine). Ferrari & F1 seem to prefer dual side pod arrangements, which fit in with weight restrictions / balance requirements, I guess.
Dave
Dave
Use one of the Odyssey range of battery. They are very small for their capacity.
I use the PC680 (185Lx79Wx170H) which weighs 6.1kg. This swings 6.7litre of Chevy V8 so I'm sure an even smaller one will suit your needs.
Odyssey are the battery of choice in robot wars as they are so strong.
Steve
I use the PC680 (185Lx79Wx170H) which weighs 6.1kg. This swings 6.7litre of Chevy V8 so I'm sure an even smaller one will suit your needs.
Odyssey are the battery of choice in robot wars as they are so strong.
Steve
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