Whats the max angle you can tilt the rad at?

Ive found a good place for it to sit but it has to sit at about 45 degrees. Is this to much? Im planning an enclosure around it to duct the air through it, will it be enough?

Thanks

Mikkel

a very good question... don't know the answer, but i'd be interested.

I probably wouldn't want to go much more that 45 degrees. i guess at 45 degrees, you're effectively halfing its surface area (if that makes sense)

and air may tend to flow over the top of it, rather than through it. but if you're ducting it it shold help.

are you using the BMW radiator?

[Edited on 6/1/09 by blakep82]

i believe that a rad should be angled buy a small amount as the air is forced onto the cooling fins, not just straight past.
but i could be completly wrong and it could be something i have made up in my head

Look at the rad fins, you will get the most efficiency from keeping the angle of the air flow (and rad) 90 degrees to the angle of the fins - which is usually vertical. If the angle is too great then no air will flow through it, so you may have issues in traffic or have to run the fan constantly to keep air moving through it.


Mine has a slight angle, but not enough to stop air flow.

Look at the rad fins, you will get the most efficiency from keeping the angle of the air flow (and rad) 90 degrees to the angle of the fins - which is usually vertical. If the angle is too great then no air will flow through it, so you may have issues in traffic or have to run the fan constantly to keep air moving through it.


Mine has a slight angle, but not enough to stop air flow.

I heard 10 degrees backwards as optimum though it might be urban myth....

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Originally posted by blakep82
I probably wouldn't want to go much more that 45 degrees. i guess at 45 degrees, you're effectively halfing its surface area (if that makes sense)

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Originally posted by MikeRJ

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Originally posted by blakep82
I probably wouldn't want to go much more that 45 degrees. i guess at 45 degrees, you're effectively halfing its surface area (if that makes sense)

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Tut, tut, someone didn't pay attention in geometry The effective height will be 0.707 at 45 degrees and 0.5 at 60 degrees (from vertical).

I suspect effective area probably drops off more quickly than that suggests though, since the air can't flow straight through the core when it's tilted.

[Edited on 6/1/09 by MikeRJ]

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As long as you have a suitable cowling or ducting to the rad it doesn't matter what angle it is set at. You can have the rad end on to the general direction of travel if you get your ducting right!

The important thing is to provide sufficient frontal area for your duct/cowl, say around 1000 sq mm (about a foot square) for up to 120 bhp. Make sure the cowl extends out in front of the rad so it will "trap" the incoming air and form a high pressure area in front of the rad. Then make sure the air you "trap" all goes through the rad and cannot spill around the sides. Also make sure there is at least as much cross section area behind the rad for the heated air to escape. This also means your fan must not block the airway too much.

Hope that helps. Cheers R

As above. I've seen completely horizontal radiators (or heat exchangers for various purposes, generally). No problem if the air is flowing through them in the right direction.

Liam

[Edited on 7/1/09 by Liam]

The Elise has a near horizontal rad, and they seem to do alright. As said though, you may need to run the fan more often, but once moving any ducting will sort that out.

If it's leaning forward and enclosed in ducting, don't you have the danger of creating lift?

Pat...

If the radiator leans forward (top further forward than the bottom) you will create lift but it should be quite small. You can also create downforce of a similar magnitude by leaning the radiator backwords - both systems will need suitable ducting.

It will depend upon the pressure drop across the radiator, usually very small, and the area of the radiator.

[Edited on 7/1/09 by JAG]

thank you all for your comments, i think im going to try laving it as it is at the minute and then making a ducting and posting pisture to get your comments then.

Also i am using a polo rad not the BMW rad(was too wide)

these cars must be very very light if the lift generated by a radiator is being discussed

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Originally posted by Mr Whippy
these cars must be very very light if the lift generated by a radiator is being discussed

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Originally posted by nick205

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Originally posted by Mr Whippy
these cars must be very very light if the lift generated by a radiator is being discussed

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You're not letting your mind wander off the down the BEC path again are you Whip?

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I am no expert here but I would say the important thing is the angle of the radiator fins to the direction of air flow.

As mentioned, you can mount a radiator horizontally but that is f.a. use if the air flow is horizontal too!!! (top diagram) - in these instances there has to be cowling to direct the air so it is perpendicular to the radiator. (lower diagram)

Now the question as I understand it is or maybe sold be, what angle can the radiator fins be to the air flow?

Obvisously the larger this is, the harder it is for air to flow through the radiator.

Unfortunately I do not know the answer and it may also depends on the speed of the air too as any object with mass does not like to change direction.

A lot of motorcycles have radiators off-vertical but I think that angle is quite small, less than 30 degrees I'd say.
Rescued attachment rad flow.JPG

According to an article in PPC about a year ago the optimum angle is 20 degrees from perpedicular. So on a Locost the top would lean back 20 degrees.
It was something to do with being more efficient if the airflow is interrupted.

20 degrees?

interesting. are you able to scan the article? or at least say haow they worked this out?

I have never seen a car radiator fitted at anything other than vertical - one would have though that if mounting it at an angle made it more efficient, this would mean a smaller = cheaper radiator would be used by car manufacturers.

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Originally posted by 02GF74

I have never seen a car radiator fitted at anything other than vertical

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Originally posted by 02GF74
20 degrees?

interesting. are you able to scan the article? or at least say haow they worked this out?

I have never seen a car radiator fitted at anything other than vertical - one would have though that if mounting it at an angle made it more efficient, this would mean a smaller = cheaper radiator would be used by car manufacturers.

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Originally posted by bimbleuk

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Originally posted by 02GF74

I have never seen a car radiator fitted at anything other than vertical

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As above go look at an Elise the radiator its basically horizontal. Duct collects air at the front and exhausts out the top of the front cover. Only issue is that new owners think they have a radiator leak when they get clouds of steam in the morning as any condensation/rain vaporises from the top of the radiator!

As a guide you only actually need about 1/4 of the frontal area of the radiator to feed sufficient air and so long as theres a pressure drop across the radiator then the air should flow freely. So ducting air away from the back of the radiator is just as important!

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Er he don't mean cover up 3/4 of the rad! Just that the size of the upstream opening doesn't have to be as big as the whole rad itself.