Fans /airflow / techies wanted

[Avantone]

The standard fan would probably be adequate if the cylinders had a greater surface area (longer fins). I still can't understand why kit cylinders are made to fit within standard cowlings when they could be made bigger with a matching cowl for relatively little extra cost).
A larger fan is going to sap power in terms of response and drag - far better to have a hybrid approach where a smaller fan keeps the air moving at standstill/low speeds, and a forced air scoop takes over at higher speeds where it will be able to provide way more airflow than the standard fan.
Managing the air after it has passed the cylinder could be improved too. The standard arrangement doesn't help the hot air exit, whereas some ducting could have a scavenging affect as well as preventing other components getting hot in the ambient heat.

[Avantone]

Im certain IF you put a lambretta through a wind tunnel every bit (or 97%) would hit the scoot and be thrown off..Surely it could be harnessed for cooling purposess ? we all know what its like in head wind :shocking: ..on a lammy getting pushed from pillar to post, engine dying under the strain..

The trick is to duct it without increasing the frontal area and increasing drag

[Andy Pickering]

the ducting is a great idea.........in some ways......as has been proven on racers................................no doubt about that.
the prob is...........if its a road scoot...........
and your stuck in slow moving traffic /jams etc...........or just going around town at low speed.................especially on a hot summers day..............not that we get many........

Well the next step from proving it cools at speed or road going would be ...and this is where I step back as Im a Joiner by trade...Integral fan to the ducting..which could create its own power so when in slow moving traffic... flick a switch and it kicks in off its own steam cooling the engine at stand still or slow moving traffic, like a car fan kicks in at a certain temp...as these giant aeroplane looking propeller miles in the sky do....produce electric...I know small scale on a lammy BUT It can be done on big scale so come on sparky people explain why...or why not...

[Andy Pickering]

Im certain IF you put a lambretta through a wind tunnel every bit (or 97%) would hit the scoot and be thrown off..Surely it could be harnessed for cooling purposess ? we all know what its like in head wind :shocking: ..on a lammy getting pushed from pillar to post, engine dying under the strain..

The trick is to duct it without increasing the frontal area and increasing drag

But tony we would all take a little extra extra drag for peace of mind on the heat front...and the cooler we could make it..the more we could tune it... to make it go faster

[sean brady scooters]

i agree that the exit of hot air from around the cyl could be greatly improved..................................
i,ve a few ideas on this myself..............based on chimney stacks.........and the venturi effect .............
sounds a bit crazy.......does it not...........
anyway..........
back to fans/scoops.........
and again.........ive tried this...........
if you combine the std fan with an intake scoop............you would prob find as i did that the two methods dont actually improve things greatley
at low speeds the fan will force air into the cowel area of course............but instead of flowing around the barrel/head..........a lot will be lost out of the scoop...........
at higher speeds............40mph plus..........the forced air from the scoop will hit the forced air from the fan.............
both of which are coming from opposing directions..............
therfore one cancels out the other..................

[sean brady scooters]

charlie edmonds uses a big scoop ...................
and also has an electric fan (extractor) fitted in top of frame................

[Avantone]

Im certain IF you put a lambretta through a wind tunnel every bit (or 97%) would hit the scoot and be thrown off..Surely it could be harnessed for cooling purposess ? we all know what its like in head wind :shocking: ..on a lammy getting pushed from pillar to post, engine dying under the strain..

The trick is to duct it without increasing the frontal area and increasing drag

But tony we would all take a little extra extra drag for peace of mind on the heat front...and the cooler we could make it..the more we could tune it... to make it go faster

Yeah I agree the more air the better, but if you can duct it without increasing the frontal area it's a win/win.

Over about 50MPH drag plays an increasing part in performance - there's a danger of self perpetuating the problem i.e. increased drag needs more power to maintain performance > more power needs more cooling > more cooling needs bigger ducts > bigger ducts increase drag etc............

[Avantone]

i agree that the exit of hot air from around the cyl could be greatly improved..................................
i,ve a few ideas on this myself..............based on chimney stacks.........and the venturi effect .............
sounds a bit crazy.......does it not...........
anyway..........
back to fans/scoops.........
and again.........ive tried this...........
if you combine the std fan with an intake scoop............you would prob find as i did that the two methods dont actually improve things greatley
at low speeds the fan will force air into the cowel area of course............but instead of flowing around the barrel/head..........a lot will be lost out of the scoop...........
at higher speeds............40mph plus..........the forced air from the scoop will hit the forced air from the fan.............
both of which are coming from opposing directions..............
therfore one cancels out the other..................

How about if the air scoop/duct fed into the flywheel cowl, into the direction of flow - that way it couldn't be possible for fan generated flow to short circuit back out of the scoop/duct

[Andy Pickering]

Is this charlies secret OHH is he just bloody good round the corners and faster than anyone out of corners..? SO sean whats the more aggresive the hot air or the cold air?....would the cold air force the hot air out through a vented flywheel cover OR would the hot air force its way back to the cylinder cowl and cause more heat....Like I said Im a joiner by trade ...

[Andy Pickering]

i agree that the exit of hot air from around the cyl could be greatly improved..................................
i,ve a few ideas on this myself..............based on chimney stacks.........and the venturi effect .............
sounds a bit crazy.......does it not...........
anyway..........
back to fans/scoops.........
and again.........ive tried this...........
if you combine the std fan with an intake scoop............you would prob find as i did that the two methods dont actually improve things greatley
at low speeds the fan will force air into the cowel area of course............but instead of flowing around the barrel/head..........a lot will be lost out of the scoop...........
at higher speeds............40mph plus..........the forced air from the scoop will hit the forced air from the fan.............
both of which are coming from opposing directions..............
therfore one cancels out the other..................

How about if the air scoop/duct fed into the flywheel cowl, into the direction of flow - that way it couldn't be possible for fan generated flow to short circuit back out of the scoop/duct

This my Ideas tony from earlier..

Something I have in mind regarding expelling the heat would be a vented flywheel cover, vented around the outside of the flywheel cover which I was summasing would turn the rotating flywheel from forcing cool air into the head area to forcing the hot temps out of the vents in the flywheel....It would certainly give it an escape ...Another idea I have is to incorporate a fan in the ducting to force more air through (non electric) which would run solely on force from the air being forced in..much the same as a childs windmill being blown..