HOW MUCH TO CUT???

[JohnR]

Our driver says we don't need to data log throttle position. He is always flat, never lifts.
DW

Dan's right. I don't lift either. I just hide all the logs that look like this: (hint: green is throttle)

[Sumner]

Our driver says we don't need to data log throttle position. He is always flat, never lifts.
DW

How about this last year   .

I know you might    be joking, but really it is good to know the throttle position if you are loging air/fuel ratio.

c ya, Sum

[Sumner]

Our driver says we don't need to data log throttle position. He is always flat, never lifts.
DW

Dan's right. I don't lift either. I just hide all the logs that look like this:

Looks like about a minute 17 sec. out things got a little exciting   .  Hooley was never able to get over 30% throttle last year at any point of the run.  Still ran 212, so he was trying.

c ya, Sum

[Tom Bryant]

I use a Race Pak System. Ron told me up front that gathering dependable scoop data was difficult. However, by using the same locations for my sensors (1 on the front of the nose and the other in the back of the scoop below the stack level) I still feel that I get good comparisons from modification to modification.

Bob Brissetti says that he uses a sensor below the butterflies and reads manifold pressure. Definitely a better way to go. He also is using a Race Pak System.

[JohnR]

...Looks like about a minute 17 sec. out things got a little exciting   .  Hooley was never able to get over 30% throttle last year at any point of the run.  Still ran 212, so he was trying.
c ya, Sum

ha ha, yes, that is where I tried my best to rip the 3 mile banner out of the ground.

John

[Larry Forstall]

Go to your local auto parts store and buy one of those "Turbulator fans" and install it in your air cleaner. Says right on the box it adds 20% more HP. Their team of "crack" engineers has done all the work, just install and go fast. LOL
     On current factory motorcycles they try to put the duct(s) as close to the highest pressure which is the center of the nose of the fairing. A Hayabusa has a pair of diamond shaped ducts each about 2"x4" which feed through the frame to an airbox which has a vacuum controlled flapper valve to control air volume for different RPM and vehicle velocity. With FI they can map very precisely for all aspects of the 0-11000 RPM 160 HP scenario.  Power improvement is claimed to be 4.6% at 200 MPH. Gonna mess with mine this year and put the duct dead in the center in place of the headlight. Should be good for 3-4 mph. SLOWER. That is what LSR is about, trying things.
    I remember years ago a top running drag racer added something just for show and sure enough all the others cars copied it. Hey Mark, I am putting fringe on your leathers as vortex generators.      Larry

[Rex Schimmer]

I just spent a couple of hours during a flight back from the east re-reading some of Goro Tamai's book "The Leading Edge" specifically about Reynolds numbers and the transition from laminar to turbulent air flow and got to thinking about how this applies to air scoops and the velocity of air through them. Looking at this information it becomes appearent that it is VERY IMPORTANT to start expanding the diameter of the inlet path right after the inlet opening because if you are going say 200 mph and you have an inlet opening of lets say 5 inch diameter and if that diameter is held for too long say even 5 inches the air will transition from laminar, assuming that you picked in an area that is laminar flow, to turbulent at which time the thickness of the boundry layer begins to thicken very rapidly and starts to choke off the effectiveness of the scoop. I think this is why you see air inlets on F1 cars with an almost abrupt transition from the inlet to a very large plenum which I would speculate drops the air velocity to a level such that the reynolds number is low enough to provide laminar flow from which additional inlet pressure can be obtained per Danny Bernoulli's formula, which really applies best to laminar flow.

That's my two cents worth, any comments?        


Rex

[Sumner]

I just spent a couple of hours during a flight back from the east re-reading some of Goro Tamai's book "The Leading Edge" specifically about Reynolds numbers and the transition from laminar to turbulent air flow and got to thinking about how this applies to air scoops and the velocity of air through them. Looking at this information it becomes appearent that it is VERY IMPORTANT to start expanding the diameter of the inlet path right after the inlet opening because if you are going say 200 mph and you have an inlet opening of lets say 5 inch diameter and if that diameter is held for too long say even 5 inches the air will transition from laminar, assuming that you picked in an area that is laminar flow, to turbulent at which time the thickness of the boundry layer begins to thicken very rapidly and starts to choke off the effectiveness of the scoop. I think this is why you see air inlets on F1 cars with an almost abrupt transition from the inlet to a very large plenum which I would speculate drops the air velocity to a level such that the reynolds number is low enough to provide laminar flow from which additional inlet pressure can be obtained per Danny Bernoulli's formula, which really applies best to laminar flow.

That's my two cents worth, any comments?
Rex

I've read a lot of that book, but a lot of it is over my head.  I just go to the conclusions and figure they have it right   .

Rex I think your math skills are way better than mine.  In college I got Thur calculus then went in the service and when I went back to school they said the year I had taken was now only worth 1 semesters credit.  I had to take more and barely made it through.  I guess I was more interesting in riding my motorcycle around in the mountains outside of Laramie.  Now I wish I would have applied myself a little more.  I still have the text book and keep telling myself it isn't too late to try and get through it, but I'll probably still be saying that the day I die   .

c ya, Sum

[ddahlgren]

I think Rex has got it!!
Dave

[John Burk]

We were at the National Air And Space Museum at the Dulles Airport last week . The planes that arn't practical to bring to the Smithsonian Air And Space Museum are there plus a lot of other good stuff . We were standing under the SR71 and our guide , a former B52 pilot pointed at the cones in the engine air inlets and described how they vary the inlet area . Hey a perfect way to peak the ram air pressure in an air scoop . A cone  tapered to a point on both ends , adjustably mounted in the scoop inlet  and record the scoop pressure like Tom's does.