Fan blades and other gumpf

[jmorgan]

One of my roundtoits is sorting the fans out once and for all. This also means fabricating a proper air box (right term??) on the inlet, very successful Heath Robinson at the moment but temps behave at lower speeds apart from stopped (of course). Looking at Spal for example you can get curved or straight blades. I know I can look at the airflow rated on the fan but is the only reason for the curved to cut noise?

[mrzigazaga]

Hi Mate..The curved blades produce more airflow and uses less power..Spal are a good make..Not cheap but then you dont want a cheap fan..Look what happened to me..just make sure you get the right size for your rad..If you can get a fan cowling or shroud it makes the fan pull air through the whole surface area thus cooling a lot quicker..And puller fans are better if you have the room for one..Cheers..Ziga

PS: Just looked at your bonnet..If the vent is above your filter then what about having an air box made that cups onto the vent and seals when the bonnet shuts..It would mean a housing for the filter to sit in, It would have to have run off slots so that any water would be drained rather than sucked onto your filter..Just an idea.

Edited by mrzigazaga on Friday 16th September 21:28

[jmorgan]

Ah, nah its the rad inlet I was referring to. The filter is pretty much as good as it is going to be, there is one location where it can be bettered but would need sorting properly. Not sure if the vents on a 400 are like the boot spoiler. For show.

The rad inlet at the front has a lot of space around it and air I thought would spill away rather than go through a rad. So I blocked the gaps. There is a huge one between the bottom spoiler and the bottom of the rad and the sides left a lot to be desired as was the top so I blanked all them off. This I think forces air through the rad. One thing I am worried about though is the front spoiler, was it there for any real reason and blocking the bottom might not be a good thing.

I need to measure the space I have, two on at the moment and they are suckers. The cowl went as I could not at the time of the last fan fail get a direct replacement.

[mrzigazaga]

Mmm..It might be ok blocking gaps up for when you are moving but what about when you are stationery?..The hot air needs to get out..Does you spoiler have the air vents in..(Two round holes) as you could put pipe from them to your rad, I think some people use them for directing air to the brakes..But i still think you need to think about the stationery mode..I might be wrong but it might be worth thinking about..Cheers..Ziga

[jmorgan]

The rad is a distance from the engine and the fans would be kicking on and chucking the air back, maybe it also prevents sucking warm air from the engine in?

Oh eck, this could get deep.

[Wedg1e]

I noticed earlier in the week that there was talk of swapping the fan round so it would blow instead of suck (or vicky vercky) but if you think about the shape of the aerofoil (or airfoil for our non-English speakers) then whilst it will still 'work' to some extent in reverse, the blade's cross-section wil be 'attacking' the air in the wrong way so must be less efficient. The only way it work properly would be if you also reversed the motor's running direction. This is for a curved blade: a straight blade would probably be better-suited to either rotation.
We've had this exact problem at work on industrial cooler units.

[jmorgan]

Not forgetting the 400's have a honking big oil cooler over part of the rad on the front.