Fans /airflow / techies wanted

[carlos fandango]

here goes matey
Q1.........................dont know
Q2..........................impossible,i would think
Q3.......................not sure
Q4........................Maximise the greatest amount of the coolest air available..........from exterior of panel work as is poss........
and also increase exit side of hot air area...............

hows that........?

When posting the questions, i had hoped there would be someone with fan design knowledge, or know someone who does.
Perhaps i should have posted it on the Fanerotica forum

[sean brady scooters]

the std flywheel fins just takes the air available.......and sends it out through the cowels.................its actually very inefficient at actually drawing air into the engine...........cos its really not like a propellor..........such as is used to suck in air and blow through a car radiator..............
in the case of lambos with std body work...........this is often pre heated and at normal /or even less than normal............outside pressure...............
any increase in pressure supplied from a scoop of any design..........would be a benefit/combined with the fact that it is fed from much cooler air to start with.........
and so.............as baldric (from blackadder) says............"i have a cunning plan"................................
more to follow soon...........................

[sean brady scooters]

just going back to question 2...........

re.... over cooling...........
i say thats quite impossible ,only cos i,ve never heard of that prob myself or even from folk/lambo owners from upper canada......norway,sweden.......or northern siberia........

[carlos fandango]

the std flywheel fins just takes the air available.......and sends it out through the cowels.................its actually very inefficient at actually drawing air into the engine...........cos its really not like a propellor..........such as is used to suck in air and blow through a car radiator..............

Thats not quite right, the fan will suck more air in, and then push it through the cowling if it was of a more efficient design. if for instance there were less but larger fins, angled in a certain way.
A propeller works in the same way a flywheel.
But the propeller is a good example of what im getting at, if the blades are adjusted in angle pitch, in flight it will push more or less air through making it go faster/ slower.
The fans on dust extractor are like the fly wheel, in that its a paddle fan and it suck it in at the center and blows it out at 90 deg. and these will suck your arm off
So if you can push twice the amount of air through the cowl even warm air it should cool it more
Anyway, its someone who knows about fans, air pressure and airflow, that would be the best person to say for certain.
Im only trying to help someone out and now my brain is hurting

[RICSPEED]

problem is fans like dust extractors are designed to operate at a set speed and most air craft props are only effective to a certain amount of revs

[dapper]

Been following this thread and looking at a photo of a lightened flywheel. Now the outside air is pulled in at right angles to the direction of the flywheel rotation, but the centre boss doesn't extend to the same height as the fins, so some of the air must pass right over the fins to the centre boss area. If the centre boss section could be extended to the same height as the fins, and the gap between the tops of the fins and the cowl was as small as possible, and a scoop was fitted to the flywheel cowl, wouldn't that compress as much air as possible toward the cylinder head? You would get a ram effect at the scoop directing outside air directly to the fins and thence on to the cylinder head. Next problem is how to cool the engine whilst stationary, as no ram effect present

[156 D]

While your talking about fan design......here is an example.....the turbo on the left is the upgrade for the one on the right and it produces roughly 50 bhp and a lot more torque on the same engine with no other mods.....these are both standard turbo`s.......as you can see the blade design on the left hand one does differ quite a lot from the other one the extra lb`s per sq ins is quite considerable.....





.............also i know it`s a car engine, but the effect of a retarded ignition on a turbo engine is far worse as it kind of sucks out the flames which are in the exhaust port due to the late ignition....

[drunkmunkey6969]

.............also i know it`s a car engine, but the effect of a retarded ignition on a turbo engine is far worse as it kind of sucks out the flames which are in the exhaust port due to the late ignition....

So on a high revving engine, the heat can either be in the cylinder (say 23 degrees BTC or in the exhaust 15 degrees BTC) and therefore 15 degrees puts the heat into the exhaust and helps the cylinder run cooler.....no?

But i guess this is about balance......because if you should be running at 23 and you are at 30....you'll get one set of problems, and conversely if you should be running at 15 and you are at 10 then you'll get a different set of problems.

But my understanding, on our scooters (not turbo car engines) and within the 16-23 degress parameters that most work with, a high revving engine will run cooler at 17 degress and hotter at 23 degrees.

If someone has overheating or pinking issues at 19 degrees BTC, you'd generally back off to say 18 or 17 degrees to reduce heat....not increase to 20 or 21 etc.

Am i wrong?

[soullad]

Carlos fandago could well have a point and 156D may well have just proved it with his picture. In fact if you look at the red fan on the right thats even got angled fins too, just not as extreme as the newer version on the left.
Again i feel it could be a case of technology overtaking the original design. So who wants to make abolt on one similar to the fan on the left outta plastic n see if its more efficient at moving air thru the cowlings?

[paul-ebsc]

the falc guy compared numerous fan designs for use with his kits and decided that none were efficient enough, so he designed his own plastic ones, similar set up to vespatronic. Pretty sure the info is in the interview with him in scootering.