|08-16-2019 05:01 PM|
Here are some pix of a Spartan RV frame with a 605 hp cummins in our truck shop.
To be honest this fan drive seems so simple I can't imagine doing it any other way but it's been so long since I've seen this thread there may be obvious issues.
Sorry the pix blow I guess I had finger prints on the lens...
|08-16-2019 04:55 PM|
Building normal tanks will be super easy for you and will make mounting etc. easy with robust steel or aluminum tanks for mounting.
|08-06-2019 03:45 AM|
|JNHEscher||Not wild about the Dart terminal block. As long as it's a good connection, it works.|
|08-05-2019 03:50 PM|
Agree. From front to back, I want to set it up as motors, rads, fans. That way the coolest air will pass over the motors.
|08-05-2019 08:29 AM|
You will want to repeat your load testing with the installation as the current draw will likely increase with the pressure load of the air restriction of the heat exchanger. Tip clearance to the shroud is your efficiency so you want that to be good.
Just guessing as no idea on the specs but from my experience I think if you want to run that electric motor you will need to put it on the cold side to keep from overheating it. Most HVAC apps like what it came from are lower temp than engine cooling.
If there is no ram air consideration you are not giving up much with a pusher from a airflow/geometry side. With fixed rpm electric cooling fans most times working on the cold side is best as the fan is volumetric so you end up with a higher mass flow rate. Your setup is not brushless fixed rpm so that does not directly apply.
|08-02-2019 07:58 PM|
|JNHEscher||Crude drawing depicting the desired arrangement. Hot coolant up the center, diverted between six cores (three on each side). First pass through the three upper cores on each side, second pass returning through the three bottom cores on each side.|
|08-01-2019 07:40 PM|
|08-01-2019 07:18 PM|
|Sask466||Sorry if I missed this part, I am having a hard time keeping up! What size of motor are to using to turn that cooling fan? Did you settle on electric or hydraulic?|
|08-01-2019 05:42 PM|
There's only enough depth for one core assembly because the motor case itself is 11" long. It's all a tight fit so I'm going to cut out the upper rails that make up the shelf structure at the top of the back wall. The rails are lapped steel that is rather rusty. Much like how the rest of the rear floor and wall has been, easier to chop it out and put fresh in. I'll raise the shelf a little so the radiator assembly has room.
Six cores bunched together and bolted without gaps is 22.75" wide and 6" deep. The center support tabs on the cores are slotted. About 0.25" of play in each tab. I picked up a 1" copper union at HD today. The OD of the copper slips right in to the ID of the core ports once the rolled lip of the port is reamed off. I'm contemplating the idea of setting these up so that individual cores can be swapped in and out without removing an entire end tank to do so. 1" copper fittings are kinda pricey when you need a cart full.
Edit: I was able to get some measurements pretty easily to plot centers between ports. 3.735". I'm still torn on what to do for plumbing them together. These are always set up with rubber gaskets on the ends that get compressed when the end tanks sandwich the cores. I won't be using that as the gaskets are the #1 failure, according to every article I've read on these.
|08-01-2019 08:44 AM|
|GLTHFJ60||If you have the depth, you could plumb two rows of cores in, with air being pulled through both sets. Run engine water through the cores closest to the puller fan first, then through the inner cores last, then back to the engine. Would help shed more heat I'd think, as the water flowing through the inner cores would be relatively cool.|
|07-31-2019 06:32 PM|
|bdkw1||Now that looks better.|
|07-31-2019 06:21 PM|
|JNHEscher||Pullers it is! I'm still planning to fab some cool scoops that will force some air into the compartment between the back wall and cores. That won't be as much forced air as a front-mounted radiator, but possibly enough to minimize the need for the fans to run. The PWM controllers will be controlled by the coolant temp sensors. I may have to adjust the impedance of the sensors with some fixed resistors.|
|07-31-2019 05:47 PM|
|mwilliamshs||The biggest loss with pushers fans is because they're in their own way. Their motors, brackets, anything not a blade, reduces flow. Pushers need a shroud even more than pullers because the pressure they create bleeds off the ends of the blade and doesn't go through the radiator.|
|07-31-2019 05:19 PM|
pressure on the fan will increase load and amperage
I assume the fan blowing through the rad would increase airflow by a similar amount to the amperage increase (minus the leakage around the shroud) but I'm no expert
every stock application I see is fans sucking through the rad, but they're also all getting forced air across the whole front surface of the rad, so putting shrouded fans in front would reduce their frontal area
|07-31-2019 04:21 PM|
I'll own up to my ignorance if that's what happened here lol. First pic is what I thought was OE mounting. The pair of locating pins at each end have different spacing, so I thought that meant top and bottom. I had them fastened together with the same distance pins all at top or bottom. The tube angle was good on one side and too perpendicular on the other.
Alternate "top and bottom" again and try mounting the links between cores rather than holding them with vice grips gets me a really nice spacing with tubes all angled well. Maybe this is how they're supposed to run. I never could tell in search pics because everyone stands back to get the entire gargantuan radiator in the lens.
Still with six cores per side and links bolted on, the fan fits just right. Center lands at the gap between the third and fourth core.
|07-31-2019 03:29 PM|
If I'm not mistaken, mounting the fans so that they pull air through rather than push it through would be the wisest. Maybe? I'm definitely shrouding these enough so that little to no air bypasses the cores. The OE pattern does look a little better. Cramming the cores together a little more to fit eight per side would increase the available pathways for air to pass through.
Almost need some kind of a positioning lattice to hold these buggers. I'm not too terribly worried about damage to these ones. Once they're set up, the system will be ready swap in brand new cores if and when needed.
Added a pic of the tubes aligned. Spreads the cores out quite a bit.
|07-31-2019 03:07 PM|
Stupid question, I see that the tubes are angled in the radiators. Can the be flipped over to keep the tubes pointing more in the direction of the air flow?
In the pics, one side looks good and the other is almost 90* to the air flow.
|07-30-2019 08:29 PM|
Ordered three Detroit-specific coolant temp sensors at $20 each. I'm going to have to test their impedance myself because nobody knows what they are. 23518092, A0041534228, and 23527830. There's two more, but at a higher cost. If any of these are in the right range, they will be the variable input for the PWM radiator fan motor controllers. If they don't work, I'll have to call up Omega to get the right thermistor picked out. Their units are $72 each.
Ideal range is 5k ohms at around 170 degrees and 0 ohms at 230ish.
Edit: First Dart Controls 65E60 on the way as well. Got a few lines on more motors.
|07-30-2019 10:05 AM|
|07-30-2019 06:27 AM|
|GLTHFJ60||There must be a point of diminishing return with regards to core count, core angle to airflow, and cooling capacity. If it were my build, I'd keep the OEM arrangement. Your narrower setup seems like it'd flow much less air and therefore might not be able to remove more heat from the coolant than the OEM setup.|
|07-29-2019 10:14 PM|
Revisiting the core arrangement. I have four cores tethered together in each arrangement. Left is OE, right is upright and upside down alternating to "fold" the cores together tighter. In OE fashion, I would only fit six cores together for a total height of 25.5". The flipped version would fit eight cores for a height of 21.75". The fan is 22". Notice I'm referring to height. I have to mock these up with them standing, but they will be mounted horizontally in the bus.
Peering into the ports shows the tube direction. The flipped arrangement runs the tubes more perpendicular to the fan flow. Don't imagine this will hinder the cooling much. I still like the idea of having 16 cores. Four fans fits across the whole radiator really well.
I'll try to lay this out for the imaginations watching. There will be two core assemblies. Each assembly consisting of 8 cores mounted together horizontally. The two assemblies will mount end to end in a parallel manner. An end tank for each outer assembly end, connecting 8 cores together. A center tank connecting all 16 cores together, but with a splitter inside wall to divert flow into a T between the upper or lower 4 four cores of each assembly, and the the other 4 cores exiting at the other half of the center tank. Basically a large, dual-pass radiator with a huge amount of cooling surface area compared to the OE rads.
I'm going to browse copper and brass flare adapters as an idea to solder them on to the core ports for interconnecting. Either that or draw up a file or two for sheet metal tanks. I would still like to make these easy to swap individual cores. Not that these hold a ton of coolant. I just like the notion. I'm thinking the reason they put steel fins on these is so that they aren't so delicate. Still, moving four of them around together without bashing them is no easy task.
|07-28-2019 11:40 AM|
|350TacoZilla||I'm pretty lost on most of your technological posts\debates but I had a laugh at the "You can't hear shit over a Screamin' Jimmy" part since as I was reading the post I was thinking "like your going to hear that fan over a 2stroke detroit" I bet you could use a airboat fan on that and still hear the DD.|
|07-28-2019 11:26 AM|
Slept on it. Here's what I take away from all this; since we're expanding the fan debate once more.
The suggestions for fewer blades versus max blades and lower pitch versus steepest pitch is confusing, to say the least. So my thoughts are, fewer blades on aircraft, more blades in pressure applications.
Obviously, aircraft are still relying on pressure for the propulsion, but their pressure peaks and falls at certain distances around the fuselage. Fewer blades allows for a greater span of time for turbulence to settle between blade sweeps so that the next blade to sweep is "grabbing" the most air that it can, and this is certainly calculated for the specific craft speed, engine RPM, etc. Also minimizes mass so that more power is applied to thrust. Articles leaning towards the fewer blade count seemed to come from aviation.
In an application such as temperature exchangers and hovercraft, where more blades are recommended, I take it this is to maintain the consistent pressure against a solid patch of surface area (a resistance to smooth flow). Hence radiator fans often have no less than 6 blades and run as many as 12. Blade pitch is definitely less aggressive than the 50 degrees I ordered from Hoverhawk. More blades adds more mass and requires much more power to turn, thus, the higher the blade count, the lesser the pitch so that they're not "digging" at the air so hard.
The owner of Hoverhawk told me to go with as large a fan as I can physically fit and the steepest pitch I could turn. I'm sure that comes from building craft that have to levitate by air pressure. When I had crunched the numbers myself, I came up with 8 blades at 35 degrees. I think I'll order some 35 degree blades and try each configuration again. Of course adjustable pitch would be superior for this. I think I remember the Multi-Wing adjustable hubs being something like 10" in diameter which takes up entirely too much fan area.
Fan noise is no problem. You can't hear shit over a Screamin' Jimmy.
|07-28-2019 08:41 AM|
but I'd try it was as few blades as possible so that the mass is the least possible. the fewer blades the better as far as performance.
I doubt that you'l really hear it while the engine is running anf it's buried in the accordion of radiators.
|07-28-2019 08:36 AM|
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