Improving Radiator performance

[asra]

Ok.Aussie Paul.[]www.firebirdgyros.com

[NiqueNaque]

Dave, etc;Here is something to thing of...What if there was more water?Add another pressurised reservoir for dissapating more heat.I did a cooling system on a welding plant which worked on pure volume of water to cool the welders while they were in continuous service, though I don't think it would pay to cart 10,000 litres of water around on a gyro... might need a gyrodyne for that.Food for thought,Cheers,Nick Tomlin.

[birdy]

More water in a systm will only mean it'll take longer to over heat,unless you put that extra water in a bigger radiater.

[asra]

And it will weigh more!!!

[Brian]

Just a thought but what coolant do you use ? I had lots of bother with a particular brand of coolant and tried diferent things to fix the overheating but without sucess till I changed the coolant to Castrol. Problem solved. Also, take a hose off and check inside the hose /radiator for any white stuff.

[asra]

Brian, I am playing around with coolants and have it leaned out to 17% with some improvement. Can you be more exact on the Castrol product you have used and the ratio to water?I spoke to a specialist motor mechanic today who, when I mentioned a new engine, immediately asked if the radiator had been cleaned out professionally and if not why not!! ...and that if the radiator had not been layed out and filled with water for even 24 hours when detached from the engine, solids could have settled and may be blocking the water flow. [:0]Current Plan is to:- 1. Get it cleaned then return it with identical coolant to before, then test2. If no improvement, try your Castrol mix, then test3. If no improvement, ask you clever people about a good cowl design (I'm thinking 3" fins at 45 degrees guiding air back into the radiator) then test4. If still no improvement, replace radiator with a bigger one (more weight []) then prayAny other suggestions on what to try?Dave

[Brian]

Dave,not sure of its name, thought there was only the one coolant available.I mixed it at a 50/ ratio.I changed motors on my gyro and being a bit tight, decided as the radiator wasnt causing any bother and looked okay, why buy a new one ! Not long after fitting the new engine, I had heating troubles and tried new coolant,new thermastat then bit the bullet and put a new raditor on and guess what, cooling problem solved.When I examined the ratiator I found a white coating on the inside, didnt appear to be blocking anything visually but it was !!

[asra]

Just an update on the overheating.I had the radiator checked and it was so clean they didn't charge me for the work and even spray painted it black, tubes and all!I leaned out the coolant even more which was marginal help.Next was a set of fins. They are about 3" wide at 45 degrees. I got an instant reduction in operating temp by about 15-20 degrees [^] The weather has cooled off (Melbourne!) and now I'm worried about running too cold [:0]Turns out the 582 thermostats open at 55C while the manual tells me 65-80 is the correct range. I get down to 60 at altitude so the last part of the plan is to thicken up the coolant til I'm in range and just tweak it with that.DaveImage Insert: 34.58

[Tim]

Technically a water cooled engine is still an aircooled engine. As long as there is sufficient airflow through the radiator, then the cooling ability is directly proportional to the combined surface area of all the finning on the cooling cores. It has little to do with water capacity or coolant type, and adding deflectors will make very little difference if you already have good airflow. Overheating is mostly due to an insulating coating inside the water passages (eg calcium) or too little finning area.Air entering a radiator expands as it heats up and causes a restriction and excess air spills over the edge with or without scoops. It is better to get the air away from behind the radiator and the cool air will always flow in. (sometimes it is better to have the scoops reversed on the back of the radiator.Tim McClure

[birdy]

Like the one I put on the RAF.[][]I noticed the fins are at right angels to the airflow Tim,while it wouldn't be as efficiant as it would be if it were set at an angle,they will still create a low pressure zone behind the rad.Hmm, just had another look,he dose have a bit of an angle there.Mount them on backwards Dave,to create a low pressure zone behind the rad.

[asra]

Thanks for the input.Given the problem of overheating appears solved, is the reason that the fins should be reversed aerodynamic? Seems like I've built a nice air brake. Perhaps reduce their size if they induce suck instead of redirection if you are telling me this works better? If the cooling gets any more efficient I'll need an engine heater []Dave

[asra]

Dave, good to see your problem has been solved.The suggestion of reversing the side fins is to induce a lower pressure closer, and directed into your radiators, from your prop. This would also aid cooling at lower RPM's on the ground, and eliminate any extra drag from the forward angled fins.The same can be acheived by mounting your radiators closer to the prop, but this is harder than it sounds.P.S like the look of your new controls and seat mount.Safe Flying !!!!!!Regards Sam.

[asra]

Hi Sam,Since my posts I've listened to the more experienced who kindly responded and have done as suggested. Pulled the fins off, trimmed them down an inch, reversed them and reinstalled so they hopefully will now cause air to be sucked through instead of acting as an air-brake.Don't really know if the advice was correct as my stick became unwell before I got to tested it and as you have seen I'm now a maintenance guy instead of a pilot.... So has reversing the fins made things better as the theory suggests? Well the old way I had them was cooling too much, which might point to a thermostat issue? Anyway, I will report when I'm flying again. Hopefully while its still summer. [^]Dave

[asra]

A word of caution,,, If those fins are attatched to the little tabs on the radiator they will break in a very short time.I was lucky, mine broke off wilst transporting on a trailer.M Barker

[asra]

I noticed a radiator on a Ducati 916 motorbike a few years back was under the seat in a low air pressure zone. I noticed this again on new Honda's and other makes of new model bikes. Radiators in low pressure zones out of the air flow. EG next to the riders knees on either side of the bike at 90 degrees to air flows. Is anyone game to try putting this to the test. It sure would help reduce parasitic drag.Just what I have noticed on the new hypo' bikes that make big hp.