Landracing Forum
Bonneville Salt Flats Discussion => Build Diaries => Topic started by: Dynoroom on August 03, 2006, 05:12:21 PM
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This Lakester should be ready for '07
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so who will get the first ride??? Seth, Tanis, Lee??? Maybe even you Mike???
Just let seth know that if he needs a guinea pig for the first runs ill be available...
Jon
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Get in line Jon :D
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THere's no room for retired timers...
Jon
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Thanks for posting the pictures. I've been dying to see what it was going to look like. The back takes a lot from the old car. Driver up front now that will be different for them. And after I took cues from their old car and got my tire/wheels away from the body now they tuck theirs in next to the body (at least in the back) :cry: .
What a beautiful body though :!: :!:
From the size of the car/motor looks like they are aiming at trying to be the fastest lakester on the planet and I'm sure they will succeed at that goal :D .
I already can't wait to see it run,
Sum
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From the pictures the motor looks like a big block, Seth must be going for the A and AA records. Great looking car and it is pretty obvious that it is going to be a real "work of art". Will this be the first 400 mph lakster?
Regardless of what LeFever's by line says, to 400 in a lakester you got to be AERO!! At 400 mph it could takes almost 200 hp to just push one wheel/tire through the air, that's 800 HP total!!!!
I think that Seth's old car was originally the Bennett-Rochlitzer-Joehnk car built around 60-61. Bob Joehnk had a garage in Santa Barbara. The basic shape was an F86 drop tank with the rear body built by Eddie Kuzma. Eddie was an Indy car builder and a master with aluminum.
You know it will be fast!!
Rex
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....................Regardless of what LeFever's by line says, to 400 in a lakester you got to be AERO!! At 400 mph it could takes almost 200 hp to just push one wheel/tire through the air, that's 800 HP total!!!!.........................Rex
If the wheels/tires are in line with each other that should be less (800HP). I'm still wondering about the distance between things and how it effects the HP needed. If one wheel/tire was say a foot behind the other one then they should be seeing almost the same air (according to one of my aero books) and would probably not need much more in the way of HP than if there was only the front wheel/tire. Now if you put them 50 feet apart I would think it would be the same as pushing 4 wheels/tires through the air. So at what point do they stop looking like one set of tires (the fronts) and start looking like two totally separate sets of tires???
c ya soon Rex :D ,
Sum
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[ So at what point do they stop looking like one set of tires (the fronts) and start looking like two totally separate sets of tires???
Sum
My information say's 1 1/2 tire dia's.
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[ So at what point do they stop looking like one set of tires (the fronts) and start looking like two totally separate sets of tires???
Sum
My information say's 1 1/2 tire dia's.
Mike are you saying that if you have, say a tire with a 28 inch diameter (front tire), then if the tire behind it (rear tire) is more than 42 inches behind it that it makes no difference if the second tire is directly behind it or at a different track width as far as the aero drag of the two tires???
Thanks,
Sum
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Does anybody have a picture or a diagram that shows what the air looks like around a tire on the ground, rolling at speeds of 100, 200 and /or 300 MPH? Or know where I can find one?
Harv
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It's a nice and clean design, cockpit and rear end are real fine, but the nose, may be you like to check this for some improvements.
I'm a little bit surprised about the nose design, this nose will create not to much necessary downforce on the front.
Looks to my opinion also a little bit too small the the rest of the car shape.
For the finish of the car....I have no fear...the other was/are absolute beauties :D
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it makes no difference if the second tire is directly behind it or at a different track width as far as the aero drag of the two tires???
aero drag :? of open turning wheels....there is no question about aero drag...the only what you can do, cover the inside and outside so good as possible....like moon disc's.....all the other...call it turbulences.... :wink:
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A while back I was reading (I think this book -- AERODYNAMICS for Racing and Performance Cars by Forces Aird) and he was talking about open wheel cars in general and stated if the car had a large wide rear tire you didn't gain much (aero wise) from putting a smaller and/or narrower tire on the front as the air would see the larger tire.
From this statement I felt that to go with a smaller and/or narrower tire in the front offered no advantage and that you should try and keep the tires in line with each other. Of course just because something is written in a book doesn't make it necessarily correct.
And even if the above was true for tires that are not separated by much distance at some distance it would no longer apply and this concerned me with our long wheel base LSR cars.
The NASCAR guys claim (at least the announcers do) that at a track like Daytona the cars can feel the draft as far as 12-18 car lengths back. Further than that and they "loose the draft" and slow down. So maybe the back tire is in some kind of "draft" from the front tire even if it is back there 12-15 feet (car wheelbase).
If two cars in the draft can run faster than one by itself, maybe two tires in the draft can run faster than one :roll: . Maybe running tires all the way down the side of the car would be faster yet :D . Dan, how many tire/wheels can you run???
c ya, Sum
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Most of the info on wheel/tires in free air are for road racing tires, short, wide and with sharp corners, the only info I have seen on narrow tires is for the bike tires that are ran on solar racers. The numbers that I used to get the 200 hp/wheel number were 5 inchs wide, 30 inch dia. and a Cd of .4, using those numbers give you about 180 hp at 400 mph. The .4 Cd was a WAG. What you really need to do is to make sure that there is a minimum amount of disturbance as the air goes around the tire, and I would guess the fronts to be very important because if they develop some big turbulance that could have an impact on the air going to the rear tires. My plan is to have a non rotating disc on both the inside and outside of the fronts along with an aero cover over the steering arm and axle end and spindle and of course have all of this flaired together and the axle to be an air foil shape.
Here is a rule question regarding using what the F1 guys call "barg boards" which are really turning vanes. Could a person use a vertically mounted guide that would be mounted on the axle, next to the wheel/tire that would extend to the rear of the tire and turn the air such that it would be turned into the low pressure area behind the tire, and I would assume that no part of this "guide vane" would be past the inside vertical plane of the tire.
Rex
Sum, I should be there late Friday morning, staying the night in Winnemucca, looking forward to seeing you.
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Here is a rule question regarding using what the F1 guys call "barg boards" which are really turning vanes. Could a person use a vertically mounted guide that would be mounted on the axle, next to the wheel/tire that would extend to the rear of the tire and turn the air such that it would be turned into the low pressure area behind the tire, and I would assume that no part of this "guide vane" would be past the inside vertical plane of the tire.
I've looked at those also and thought I would make some to try later if I ever get the car done and actually running. I think to really be effective you would have to have some wind tunnel time (not in my expense account). You can see the effect by holding you hand out the window or if you have a car old enough to have window vents at the front of the side windows. Since I don't have air on my GMC I get to play at directing air on me going down the road a lot :wink: The other thing is it doesn't take much change of angle to redirect it to a whole other area. They also used the "coke" body shape on the car to direct air. I don't see anything in the current rules that would disallow them as long as they are inside the wheel plane.
I'm still not getting my question answered though about whether you have the same aero drag on both the front and rear tire or less on one or the other if they are in line with each other and if so how long can the wheel base be before it goes away????
c ya, Sum
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That car seems exceptionally long for a single engine car. One of the things that Dr Seal at Western Washington University said, when we had Marlo's model in the tunnel, was to try to shorten the car somewhat. The length of his car was determined by the size of the drive trains and the space necessary to plumb it plus a nose and tail.
Seth's car looks more like it was designed for super sonic speeds. All of us could wish for that but it's highly unlikely with a single engine. It will require a long trailer to transport it unless he choses to sling it under Tanis' bird.
Sum, Slim and Rex, try to link up with me at Salt talk time.
FREUD
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Dan, how many tire/wheels can you run???
A minimum of four in contact with the ground at all times.
DW
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Fascinating topic-400 mph open wheeled, wheel driven!
Informal conversations with Top Fuel wing wizard Mike Mageira thru the years indicate that at about 185 wheels of substantial width generate lift (there's a bunch of books that back this up).
Thusly, one would assume that approaching and beyond this speed range one would have to generate DOWNFORCE one way or the other (or you'll be an ice racer!).
Don't believe adding huge weight to the vehicle will suffice since the Bonneville course length is acceleration limited.
Not a lot of studies have been done on the aero influence between tandem, or near tandem wheels, but the wake of the body ( off the nose and between the wheels) may influence what the front wheel wake does to the rear wheels re drag reduction.
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This one will be at Speed Week '06
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From the pictures the motor looks like a big block, Seth must be going for the A and AA records. Great looking car and it is pretty obvious that it is going to be a real "work of art". Will this be the first 400 mph lakster?
Regardless of what LeFever's by line says, to 400 in a lakester you got to be AERO!! At 400 mph it could takes almost 200 hp to just push one wheel/tire through the air, that's 800 HP total!!!!
You know it will be fast!!
Rex
Just a little fuel for thought... the old lakester was setting records at 300 mph. The power required for that speed was less than 950 hp, this was done with both 258 & 302 CI engines turbocharged. The new car has the same frontal or a bit less than the old car. The engines will be average size big blocks, wonder how fast it might go...
There was a time back in the early '80's when they said a production car would never go 300.
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I'm still not getting my question answered though about whether.....
Sum,
it's hard to get here a answer, due to this, that the answer based a combination of a lot of different factors.
But I will try, to get you a idea.
The disturbed airflow behind a NASCAR or Formula 1 is about 50 yards.
Behind this cars - in this 50 yards - is a very turbulance air - more - it's a vaccum air - this is the reason why a car behind a other car can go faster - the airpressure which the front car get, exist not behind the front running car - in other words, behind the front running car is "less" air :wink:
To your question, if the wheels could stand in line or stepped.
At first, with a short wheelbase, the rear wheel is full in the disturbed air from the front wheel - but this air is different than a air behind a car, due to this that the wheel is turning forward, which create a totally different airflow. The air behind a turning wheel goes backwards :? at first - this sound very strange, but you can see it in a windtunnel.
When you cover the wheels inside and outside with a disc, this airflow will be much cleaner.
If you run a longer wheelbase, the airflow is a little bit cleaner, before it "crashed" into the rear wheel, which helps if you run covered wheels.
Much more important is the distance between the wheels and the car body, how far you be away from the body. If the airflow around the car is not touching the wheels, the car can go faster. In other words - if the disturbed airflow from the wheels is not crashing into the body airflow, the airflow around the body is smoother.
As you see, it's a combination of a lot of factors.
It will be need too long to explain here everything, but I hope I gave you a idea what all is involed into the airflow.
Let us talk at the Salt Talk about this issue. There it's much easier to explain.
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Sum, your analogy of the roundy round cars going faster as a pair when they draft doesn't work as a comparison to a tire following another tire. The reason is that the two cars running close together have twice the horsepower while running as a combined aerodynamic unit. The tire in front of another tire has one power unit. This barely makes sense to me and I just wrote it.
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Mike do you know what tubing dia. the upper rails are, "1.75"?
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Google ---Lakester--- on page 10 there is a link to something that "MAY" :? give us some ideas of aero on Seths new car!
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barely makes sense to me to either--wouldnt the aero be the same at bonneville with one tire following the other as with both tires in the same position rolling down a very steep hill at the same speed-hmmmm just a thought willie buchta
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We are in the group that like small narrow front tires, tread width about twice the car width and narrow as possible rear tread width.
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I may be joining the narrow rear tread with next season, as well as fairing my frt. axel and a small rear wing.
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I may be joining the narrow rear tread with next season, as well as fairing my frt. axel and a small rear wing.
Sparky, just be sure that you don't have any body axle fairing wider than the inside of the rears. Axle shape is up to you...
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What do you think it would have to be to not be considered fairing? :roll:
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What do you think it would have to be to not be considered fairing? :roll:
Like he said it sounds like the axle tube itself can be whatever shape you want it, you just can't attach something to it that is aero and inside the plane of the tires.
I have to call you we won't be coming next weekend,
Sum
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Sparky, no part of the body or axle fairing is wider than the narrowest inner vertical plane of the tires. It does not say the axle cannot be aero tubing, it just says you can't have any body parts sticking outboard of the inner plane of the narrowest tires.
We mounted an air scoop on the side one year, tech said that was body/fairing, it was just for a test we were doing, we had the NACA duct with us, to run a comparison.
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Google ---Lakester--- on page 10 there is a link to somethinGoogle ---Lakester--- on page 10 there is a link to something that "MAY" give us some ideas of aero on Seths new car! http://avusdesign.com/Lakester.html
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If you look at my roadster, it has a sheet metal airfoil shaped cover over the tie rod which is directly infront of the axle. Ib am told this was protested when the car was new and found to be legal. People have complained about it since I have owned the car but no protest.
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What do you think it would have to be to not be considered fairing? :roll:
Like he said it sounds like the axle tube itself can be whatever shape you want it, you just can't attach something to it that is aero and inside the plane of the tires.
I have to call you we won't be coming next weekend,
Sum
Sum, how about warping the round front axle tube with sheet metal to create an aero axle? Weld sheet metal permanently to the axle tube and should meet the rules.
John