VD Aero
In various threads I've heard that the VD conversions have a drag problem. What are the main issues affecting the drag? High nose, sidepods, floor? Any recommendations on improving the aero w/o windtunnel? Tuft testing can indicate airflow but I don't think it's effective for diagnosing drag. And, sometimes something that seems intuitive actually increases drag. Help!
Aero stuff...
I campaign a VD conversion that has a few issues in the aero dept. - Had an 87 Reynard that I had "tunnelled" and was suprised at the pressure diffs and flow direction changes. Laminar vs turbulent and the like. A good source of ideas is the aviation community - search "gap seals" and the like. There are also a few good posts out there about aviation heat exchanger design in experimental aircraft that could give you ideas. They concern themselves with flow around and also through the machine! Some car constructors have not placed a priority on slipperiness - we are in the early stages of the product development cycle and should expect greater up-front costs (time and $$) until the ideas gel. Watch an FV race for more ideas. Time to start a VD conversion "Owner's Group"?
Man, what a drag...
Not sure about any drag issues, but those cars could definitely do with improvements to the cooling, not so much the oil, but the water.
I would see 225 water on very hot and humid days in my RF99 conv, running one VD dual pass rad in the left sidepod.
These engines do not survive very long at that punishment level.
Coop,
Cat national had 94 degrees on saturday's sessions and 91 degrees for the race on sunday. I was on the thermostat both days with a single pass C&R radiator. I removed the protection screen from the very front of the pod opening and made a different style near the front of the radiator. Dropped my water temps 40 F. "No worries mate"
Oh my. I'm from another class, but am considering adding a screen between the air inlet and the radiator on my car. I assume that you had a relatively fine screen, and that both 1) moving the screen back, and 2) using a larger screen helped you so tremendously.Originally Posted by Northwind
Was your screen flush with the outside skin, or just inside? Are you willing to tell us the before and after screen sizes? I'm thinking of using 1/4".
Chris
I'm curious about this also. I changed the shape of my side pods on my homebuilt and openend the front entrance on the new narrower side pods 1" and the temps went up. Had the same screen door mesh from Lowes on the inlet on both. Was told to change the screen to a larger pattern. I went to a 1/4" mesh from McMaster Carr and didn't change the temps one frickin degree. All it did was let more debris and grass in to damage the coolers.
Please describe what exactly you did if you don't mind.
Thanks,
Jerry
Chris,
I had 1/4 inch screen mounted right at the opening. The change I made was using the expanded sheet metal screen that they use to hang stucco or mortar to walls from Lowes. When it is pulled in manufacturing it has a draft angle to it which matches the transition angle needed to direct the flow to the VD radiator. I then mounted the screen with the proper draft angle to the entire length of the radiator, not the opening. It allows much more air flow to the system. I have heard of other people using honey-combed aluminum for the same purpose only this material is much cheaper. It fit my budget and works.
Oh, fascinating! My new radiators - two, one in both sidepods - will be tilted (leaning backwards, I'm thinking, so I can see bent fins) about 45 degrees to vertical. This will inhibit air flow through the radiator, and I have been thinking of ways to help this. Guiding vanes, horizontal plates that lead up to the radiator face, etc. I'm not sure if, say, a honeycomb oriented to the radiator fins would help. The on-line info is very unclear - and I have researched rather intensely.
I had been thinking of a screen 90 degrees to the air entry, where there is a nice, convenient side pod support to mount it on. I am re-considering this now. . . And I will use that same stuff from Lowes!
I actually found a company that makes custom radiators with the fins oriented at 45 degrees. I'm waiting for a quote, and am certain that I will need several stiff drinks when I get it. And that it will be well beyond my budget. . .
Chris
Oh boy, Oberto!
Company name = ________________
Rick
http://www.ahfabrications.com/inform...hghoa481q65jr6
In England.
Chris
Thanks Chris
I sent out a message yesterday to the e-mail addresses of the VD/Novak F1000 owners that I know of (which I think is all of them.) I have received responses from 5 of them. If you own one of these cars and didn't get the message, or would like to join the owner's group, send me a PM or e-mail and I'll add you to the list.Time to start a VD conversion "Owner's Group"?
Mike Beauchamp
RF95 Prototype 2
Get your FIA rain lights here:
www.gyrodynamics.net/product/cartek-fia-rain-light/
I would hope
that you included a certain Giancarlo Di Coopola on that list!
I did not but you have now been added!
Mike Beauchamp
RF95 Prototype 2
Get your FIA rain lights here:
www.gyrodynamics.net/product/cartek-fia-rain-light/
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