EJ22 Radiators?

[asra]

Hi guys,What type of radiator is generally accepted when running a sub EJ22. Are the EJ's a 'hot' engine when installed in gyro's?Any help here will be greatly appreciatedCheersPaul

[NiqueNaque]

Here's a thought for you..The power of an EJ 22 is about 150 hp? or about 50 x 0.7 = 105 kW. I C engines are about 60 % fuel efficient [very roughing it here].. so about half of the power output again has to be radiated to atmosphere, by your radiator, so, your radiator has to disappate about 40 kW.. [sounds like such a waste, must be wrong as the exhaust gases would take most of that heat with them, say conservatively about 20 kW]. You have to allow for a 30 degree temperature differential between the air going into the radiator and the water temperature so the air picks up the heat, the mass flow rate of the air depends on the speed of the gyro, but what if you're testing it on the ground?..... ah, bugger it, the manufacturer did all this and came up with a radiator, just use that.. I've got one for and EJ 18, its about 600 x 450 x 20 deep, alloy, very light and see though. Mount it high to move your COG up to achieve CLT a little more easy, heat rises, and stones have difficulty getting that far up.. If it is within 2" of your [radiator - wrong, corrected to -] Propellor its performance on a hot day is more likely guaranteed than not.Hope this helps..Cheers,Nicholas TomlinAlarmist - www.alarmist.com.au - we scare for you

[asra]

The EJ22 seams to be easier to keep cool then a EA81 & I agree with Nic on placment above the engineButch S

[Echo]

VW Golf radiator suits - I'll find pic of set-up. Runs just under 80 deg C two-up. ( long winded replies are often confusing )

[Echo]

Can't get pics to load - post e-mail address & I will forward them on to you Paul.

[NiqueNaque]

Here's a question for you to consider:If you have a look at cars which have an electric fan system they get by through using a larger surface area radiator and cut the fans in only when the temperature reaches a certain point, we've got a fan running all the time so we should use it.I ended up relocating my radiator such that it sits 2" in front of the prop and is about 1/2" below the belt and pulley wheel of the redrive - I did this because the bracket was deadly simple to make and the plumbing was dead easy, I worry about its efficiency though and will be stress testing it today to see if at full power for 20 mins it keeps the heat under control. I can't do this in my back yard due to wind factors from the prop.One thing I did though was to have a look around for those 'strip brushes', the likes of which you find attached to the bottom of your door to keep the bugs out of home, or you see larger versions on the wheel arches of trucks. I was thinking to make an arrangement to extend the brush out to the prop and just clear of it to increase the draw through the radiator - just the core, not the headers.See www.josco.com.au Has anyone tried this?Nicholas TomlinAlarmist - www.alarmist.com.au - we scare for you

[asra]

NiqueNaque I think you'll find a marked decrease of your thrust from your engine doing this. you are effectively cutting off a relitively large area of free air goint to your prop this wayand though it will get some air through it , it will not be as much as the prop normially sees, now what that will do for prop rotation /ballance I have no idea maybe nothing , maybe some,you might get a shake that you didn't have before.... hard to say.... 2" is purdy close i'ed say 8" to a foot away would probly be betterand still pull air through the radiator but without sheilding the prop near as much. ... believe me when I say you do not want to close off the prop to the radiator completely , the force of the prop could easily pull the innards out of the radiator.... calculate the vacume of something like that if you want , its purely guessing in my part. automotive radiators are fairly stout in their makeup and should hold up to most applications, but remember you are useing it in a place where the winds are much higher than it would normially see and the suction is also alot higher than normal.... with that in mind a smaller radiator should be adiquite in normal flight but it would limit ground testing due to its smaller capasity..... obviously.just thought I'ed put in my 2 cents worth ! good luck on your testing ! cyaBob......." Momm'a alwayse told me , Son the impossable is only a little bit Harder... and ya know I do believe She was RIGHT ! "

[asra]

Thanks Echo,email is rotorque@tpg.com.au (nothing confusing about your response, appreciate it..)NiqueNaque,Thanks for the info, but my EJ is for a small helicopter so RAM air is an issue. I am interested in any aluminium radiators that are small enough to do the job..... The question regarding whether the EJ's were considered hot gives me an idea of what I am up against when it comes to cooling these engines.I am currently running the stock liberty radiator on the engine stand, they are pretty good radiators but not quite right for my project. Thanks guys

[NiqueNaque]

Bob,Good consideration, but:1. I found the existing radiator performed much better at the location cited, but not well enough, I'm going to have to up size, at 4800 revs - static, which is about 400 short of flying revs, it was reaching 200+ f and still climbing, pulling it back to cruise revs - 4400 did not allow the temperature to drop back, it climbed more but more slowly, so my radiator is undersized, the jump in HP after fitting the redrive is in the order of 50%, so the radiator needs upsizing.2. The radiator is generally to be located as close to the centre of the prop anyway, so it largely gets the dirty air, as does the prop, but a check on thrust figures will be worth the effort just to confirm. The air going to the outer 2/3'ds of the the blades should not be fouled other than by the superstructure of the machine, and this time it will go on top, that will mean the machine's drag profile will be improved as will its proximity to CLT, or it may end up being LTL.3. The wind speeds will be higher, the gyro flies at 50 ` 60 kts, but to generate that speed the fow rate through the prop will be much higher, say 80~90 kts as a guess, but still well within automotive ranges4. As I discovered by **very carefully** inserting my hand into the space between the prop and the radiator [yes, I still have it] you must be mindfull of the pulses that are generated by the prop moving past the radiator, this must be considered to some degree and I think regular pressure testing is required to make sure that the radiator has no cracks, to the point of doing it in every preflight. It is amazing as the amount of heat flowing past your fingers and the difference between the front and rear sides of the radiator in terms of heat flow.I'll mount the EJ radiator on it tomorrow and see what happens.Cheers,Nick.Nicholas TomlinAlarmist - www.alarmist.com.au - we scare for you

[Mark Horan]

Nik egg, You may find that "one can have the radiator TOO CLOSE to spinning bit" I know that I cant back this up with much usefull science exept that remember reading sometime ago (thanks Dr John) that some germans building aircraft around the 1940s used the same reasoning that you have and found it to be cr@p.Something about those pulses you mentioned?love and kisses,Mark.

[asra]

Right O NiqueNaque ! its the pulses that worry me and the vacume ...sucking the innards out of the radiator would be a bad thing indeed .... on an automotive fan they usually have 4 to 8 blades this would cause a less intense pulse i would think... that pulse comeing arround is actually slapping into the side of the radiator then it is being ripped offthe prop, the prop continues its path under a vacume that is alot higher than normal, (say the max. vacume air can have at -20 p.s.i. ) then it reaches the other side of the radiator where it re aquired the the pulse head that follows the blade arround, this has got to be a hard thing on the berrings and what not of the re drive...but at anyrate, that pulse being drug through the center of the radiator, or actually following it now.... could actually stop the flow of air by setting up turbulance.instead of alowing a constant flow of air through the heat exchanger... something to think about anyway..... I know what you mean .... I counted my fingers after placeing my hand close to the leading edge of the prop by my pre-rotator pully.... and yes the pulses are knoticable !.... I've seen Subaru's with the radiator Up high on the mast angled foward with the aft portion of the radiator at about the center of the engine the top near the mast, but not attached to it. sure makes it look big sitting up there ! ....I don't know if you've tried useing a lower tempiture thermostat or not or try removeing the thermostat alltogather, which I don't care for that idea much but it has been known to work on autos throughout history.... it is not uncommon at all to replace a suspect thermostat with a brand new thermostat only to have it not work eather...in a ford pinto I had I replaced the thermostat 3 times and on the 4 one i finally got one that worked ! .... the others would never open or stay locked at full open(mostly just not open at all! ) you may well have the same problem with your subaru. , though its realy hard to check on a gyro like that ...I checked my thermostats by pulling off the radiator cap (when cold) and running the engine at just above idle till it was warm and the thermostat opened.... you can tell by looking in the radiator and seeing the flow of water / antifreeze. on the gyro that might be hard to do , even risky ! infact you might loose all the coolant if you take the cap off ! I dunno !... take a few pics Nic and show us your instilation ! , would like to see the redrive again anyway ! good luck ... and keep ur fingers BACK ! c ya !Bob....." Momm'a alwayse told me , Son the impossable is only a little bit Harder... and ya know I do believe She was RIGHT ! "

[asra]

Nique Naque... I was wondering what type of radiator that is anyway... sense there are verious types now days ... ones with tanks top and bottom and ones with tanks on the sides .... seams a shame to have to replace the radiator , when it was working.... but you are definately working the engine harder now with the new redrive on it. I prefure the top and bottom tank type of radiators, where the water has to flow through the cooling tubes to get to the other outlet , though the side taks the principal is the same application doesn't alwayse work that way, it seams to me that a side tank radiator has Hot spots in it.... mostly at the top of the cores and the bottom is just warmin contrast the top/bottom tank the entire thing gets hot .... I don't know if this is a common observation or not but thats been my luck...though My subaru EA81 turbo in the sedan out there seams to cool fine it is parked because of a thermostat sticking and burnt the engine up.... it runs NOW for about 35 minutes before loosing all oil pressure ! so it needs a rebuild !c yaBob..." Momm'a alwayse told me , Son the impossable is only a little bit Harder... and ya know I do believe She was RIGHT ! "

[NiqueNaque]

Marcus Horribulus,So nice of you to lend some advice Councillor.I suspect that to some degree, the centre of the timber prop not only suffers from pulses but also recirculation, ie, the air goes around it in circles. If my smoke sticks hadn't got wet I'd be able to do a smoke test and check the flow pattern around the radiator to confirm this. I daren't park my fingers in there when the engine is going full belt - way to dangerous, I step out at 2000 though I'm sure the consequences would be just as diabolical at that speed as any other.I'll go and take some photos, for a comparitive view.I think the facts of it are that the engine is now able to do 5200 revs, where as before it would only be able to do 4000, and the power is up from about 40 hp to about 70 or even 80, the heat load probably does not go up in direct proportion, it would most likely happen in an exponential fashion as funny things happen with friction when you start doubling speeds, for example the flow of the fuel / air mixture, exhaust gasses, oil and water through their various circuits - the friction losses in the conduits goes up in the order of squares, so doubling the speed quadruples the work and therefore the heat load, the same thing may be said of the slipper bearings on the engine crank pins, gudgeons and journals.To give you an idea if you double your velocity, you quadruple your friction losses, ie, 2^2 = 4If you increase flow by 41%, you double your friction losses - because 1.41^2 is 2 or near enough [try this on your photostat machine at work - if you want to double the area of a page, use an expansion factor of 141%, this jumps from A4 to A3. Don't believe me? - joint two sheets of A4 at the long edges = A3. I use this for converting a drawing from 1:100 scale to 1:50 scale, a good trick for a councillor looking at some approval drawings without the need for seeing eye dogs]If you increase your speed by 10% you end up with 21% more work, in my case I'm increasing engine speed by near 30%, so my extras are in the order of 70%, a fair jump if things go in the order of squares.No doubt you grok this...Nicholas TomlinAlarmist - www.alarmist.com.au - we scare for you

[asra]

Nice info to have Nic thanks ,,, yep no doubt a new bigger radiator is in order ! have a goodenBob....." Momm'a alwayse told me , Son the impossable is only a little bit Harder... and ya know I do believe She was RIGHT ! "

[Brian]

The Nissan Pulsar radiator mounted like this is the way to go. The 2.2 Suby runs at 85C on a 48 C day while workingImage Insert: 60.08