World's lowest drag vehicle

[joea]

going as fast as you can may not entail rocket science......

but going as fast as you "could" may very well entail rocket science.....!!!!

[Ratliff]

180 mph on 75 horsepower.

I think that, combined with the brake technology of the time, is the real reason dustbin fairings were banned.

Maybe if Moto Guzzi had the kind of brakes available today it might have been a different story.

Put a dustbin on one of those 260 mph Hayabusas and you'd be looking at a 300 mph bike.

[PorkPie]

Hi Eric,

so, I can understand "blunt" as a try of a Kamm rear end

but so as a lot of racers are built - the side panels are a "try" of Kamm, but between the left and right side panels from the rear end are the chute tubes and "wholes"...means a open rear end without a closing sheet metal....which can create a vacuum behind the car....and with this bad turbulences...

To this a information - we are using a Kamm rear end at our streamliner - and we also get under the chute tube a open space.....but we need this to get the air out of the streamliner which goes thru the radiator....otherwise we would get a overheating problem....and if the Kamm end is done properly it's not too bad in a so configuration

[Ratliff]

Hi Eric,

so, I can understand "blunt" as a try of a Kamm rear end

but so as a lot of racers are built - the side panels are a "try" of Kamm, but between the left and right side panels from the rear end are the chute tubes and "wholes"...means a open rear end without a closing sheet metal....which can create a vacuum behind the car....and with this bad turbulences...

To this a information - we are using a Kamm rear end at our streamliner - and we also get under the chute tube a open space.....but we need this to get the air out of the streamliner which goes thru the radiator....otherwise we would get a overheating problem....and if the Kamm end is done properly it's not too bad in a so configuration

In the links belows you can see how the chute cans were housed on Fred Larsen's car and The Blue Flame. Lynn Yakel would have preferred a longer taper on Larsen's car, but Larsen didn't have a long enough garage.

http://www.landracing.com/forum/index.php/topic,3900.30.html

http://www.landspeed.com/classroom/classbluelfame.html

Since you've mentioned using a radiator, you may also want to take a look at how the intercooler was mounted in the tail of the Honda Hawk.

http://www.landracing.com/forum/index.php/topic,3996.0.html

[Eric_M]

I have to agree with Bakker, results are the key. It's one thing to have a low CD , but the execution is just as important. BUB Seven has a Cd of .08 both calculated and tested full scale at the wind tunnel. While this is superb, the whole package makes it happen.

This year we toured with the Cycle World show circuit featuring the Joe Petrali bike. The tail of the bike was tapered and appeared to have a low CD, but for his the record run Petrali removed tail bodywork. It looked right, but didn't perform in reality.

So what it really boils down to is the time ticket, that is the only way to validate any of these designs. Theory is great, but application is essential- Eric

CycleWorld Shows
http://www.motorcycleshows.com/motorcycleshows/Atlanta+Features/Worlds-Fastest-Motorcycles/ArticleStandard/Article/detail/451724

[Ratliff]

In the sixties, when he was chief steward for USAC, Joe Petrali in the absence of any specific rules governing construction had to tech inspect cars such Breedlove's first and second jets, Walt Arfons' rocket, and Art Arfons' J-79 jet then decide whether they were safe to run.

[bak189]

Mr. Ratliff.............brake technology had NOTHING to do with the banning of Dustbin Fairings in FIM roadracing back in the late 1950"s..................
 You appear to have all the important
information at hand...................we will all give you a BIG atta-boy if you get the answer right............
(hint... the answer is noted much earlier on this forum)
O.K. people no fair helping Mr. Ratliff.....................

P.S. However, you are right on, regarding a Dustbin on one of the 260mph. solo bikes..........
but the conditions would have to be almost perfect.............................................................................

[Matt-G]

Here are 2 photos (if I can add them properly) of a motorcycle with a streamlined shell which has a "dustbin" type front and a "Kamm" type rear. The bike went well in crosswinds when loaded with about 90lb of fuel loaded down low and got sensitive when the fuel was used up.  It seems that a low CG helps the sidewind stability even with a large side area.  The bike ran 81+mph at El Mirage in 1982 or 1983 with about 10 hp from a detuned Suzuki GN125 motor. It was designed for a High Mileage contest, so the rules were wide open.  One way to test a theory is to build and test, that is why Bonneville is so much fun! 

 






Glad to see the forum active again.
Matt G.

[Ratliff]

Mr. Ratliff.............brake technology had NOTHING to do with the banning of Dustbin Fairings in FIM roadracing back in the late 1950"s..................
 You appear to have all the important
information at hand...................we will all give you a BIG atta-boy if you get the answer right............
(hint... the answer is noted much earlier on this forum)
O.K. people no fair helping Mr. Ratliff.....................

P.S. However, you are right on, regarding a Dustbin on one of the 260mph. solo bikes..........
but the conditions would have to be almost perfect.............................................................................

I've seen one of the Moto Guzzi dustbin bikes up close in person. It's so low if you were standing on one side of a Hayabusa and it was on the other you might not even know it was there.

I also have a 1974 SCTA rulebook. There were no rules banning anything on a sit on bike. All the rules say regarding bodywork is "any streamlining apparatus is permitted that is consistent with the safety rules and good design practice." There were exactly twelve classes for bikes, six fuel and six gas, based entirely on engine displacement. Whether you had a race frame or a production frame didn't matter.

[sockjohn]

P.S. However, you are right on, regarding a Dustbin on one of the 260mph. solo bikes..........
but the conditions would have to be almost perfect.............................................................................

Just curious, I have not witnessed a 260mph bike run, are we talking stock bodywork Hayabusa's, or something else?

I did a quick calculation (ok, I plugged it in an online calculator) shows a stock body work Hayabusa would need just over 400 horsepower, so that seems reasonable to achieve.  Not easy, but there are many claiming much more power than that.

To go 300mph on the same horsepower would need to reduce the stock Cd to around 0.36 (from the claimed 0.561)  This seems like a bit of a stretch to me, but maybe I'm missing something.  Tires would be a BIG issue as well.

Back to the original topic, there is a classic photo of Burt Munroe's Indian, and beside it a much earlier design Indian.  The latter design, and most of the "modern" motorcycle streamliners are low and long (The only exception I can think of is Dan Hanbrink's liner, but not really modern and had some different design goals in mind).  I think the design process evolved for good reason.

The HPV designs have to position the rider to make good power, and weight is critical due to the short amount of time that a person can generate high power.

 

[Ratliff]

P.S. However, you are right on, regarding a Dustbin on one of the 260mph. solo bikes..........
but the conditions would have to be almost perfect.............................................................................

Just curious, I have not witnessed a 260mph bike run, are we talking stock bodywork Hayabusa's, or something else?

I did a quick calculation (ok, I plugged it in an online calculator) shows a stock body work Hayabusa would need just over 400 horsepower, so that seems reasonable to achieve.  Not easy, but there are many claiming much more power than that.

To go 300mph on the same horsepower would need to reduce the stock Cd to around 0.36 (from the claimed 0.561)  This seems like a bit of a stretch to me, but maybe I'm missing something.  Tires would be a BIG issue as well.

Back to the original topic, there is a classic photo of Burt Munroe's Indian, and beside it a much earlier design Indian.  The latter design, and most of the "modern" motorcycle streamliners are low and long (The only exception I can think of is Dan Hanbrink's liner, but not really modern and had some different design goals in mind).  I think the design process evolved for good reason.

The HPV designs have to position the rider to make good power, and weight is critical due to the short amount of time that a person can generate high power.

 

The exposed front wheel on a conventional motorcycle generates A LOT of drag. A well designed dustbin fairing might be enough to turn a 260 mph Hayabusa into a 300 mph Hayabusa.

In any case, a pair of canard wings like the ones Arvil Porter installed on Larry Welch's rocket bike (the first 200 mph drag bike) might be a wise precaution.

The motorcycle streamliner as we have known it for the past 50 years was created by Stormy Mangham back in the late fifties.

[joea]

Thanks Matt G.  that is very cool of you to post that information...ie real world execution........
and feedback........first hand....

[bak189]

We have had long discussions regarding Dustbin fairings on this forum in the past...........................
As we now know a Dustbin is legal at the BUB..... racing under AMA/FIM rules on solo bikes....however, as per the rules the fairing has to be mounted above the axcle still leaving a good part of the front wheel exposed.................
Running a Dustbin on a sidecar allows us to bring the fairing down to approx. 3 inches off the ground covering the front wheel completly except for the tire........this is where one gets full benefit of the fairing.  Our sidecar as a whole
has a long way to go regarding good Aero, partly due to the fact we use a passenger in the sidecar, but the Dustbin fairing gives us approx.
20 to 23mph. over running"naked".........................
But it can be a hand-full in a cross-wind..........

[Ratliff]

I think comments made by Sir Malcolm Campbell in 1946 when he wrote regarding his upcoming attempt with the first turbojet boat are applicable to the question of dustbin fairings and enclosed tails. "Well, it goes rather deeper than the mere desire to set up a new record. Standing by themselves, these speed records may mean much or little, as the case may be. Of course, there is a great sense of personal satisfaction in setting a figure which challenges the opposition but, if that were all, I should without much hesitation say that the effort was scarcely worth the time, trouble and expense involving in building a world-beating car or boat or aeroplane. It certainly would not be worth while if the achievement did not constitute a landmark on the road of progress. Every time we set up a new record of speed, either on land or water or in the air, we have learned something which can be applied to development and have travelled another distance towards that relative perfection of the machine which is the goal of human endeavor."

So if a Haybusa goes 260 mph does that by itself constitute a "landmark on the road of progress"? (Assuming such ideals are still remembered today). Have we "learned something which can be applied to development and have travelled another distance towards that relative perfection of the machine"?

[Blue]

going as fast as you can may not entail rocket science......

but going as fast as you "could" may very well entail rocket science.....!!!!

bak149 has it right, if anyone thinks for a second that I am a cubicle engineer they need to read the signature under my avatar.

I believe that we need both theory and testing.  From the practical side, guys like Willie are the best since they are unwilling to put up with theory that contradicts their experience while at the same time they are willing to accept theory that explains what they have felt and seen in real life.  We have to test.  If theory doesn't match reality, it is the theory that has to change.

BUT! Incomplete theory or messy interpretation of that theory often leads to messy data that only confuses the issue. We have to have clean data.  That means a clean interpretation of the theory and a clean test vs. a contrary theory.  There are some on this board who want to just keep pointing at history and old theory without adapting to modern experience.  I don't accept any combination of theory and data without some explanation of why they explain each other.

On the ALSR, I had many, many people shoving theories at us.  One of the best examples of what I spit at was one graduate student who said he had evidence that transonic objects created divergent pitching moment in ground effect regardless of alpha or Mach number...

(if you're an aerodynamicist, you're laughing right now...)

His application to work on our program was accompanied by a statement that he had completed his doctoral thesis and was going to conduct experiments that proved his theory.

My dad would've boxed his ears for that.

Experiment tests theory, and nothing is completed or proven until it stands up to contrary (or "devil's advocate") testing.  That's what Bonneville is for.

Let's just remember that the salt is a dirty experimental environment.  Soft salt, wet salt, bumpy salt, hot, cold, wind, engine conditions, chassis tuning, got-to-make-a-run-now-because-if-I-don't-it's-next-year-itis, etc. etc. etc. all pollute the data.  There's a lot going on out there that pollutes the aero data.  Lots of people have read my posts here and believe that I can help them.  I'm flattered, and I even want to help as long as it doesn't cost me anything.

So tape some yarn to your lakester and send me the pictures.  You only have to go 60 MPH on a country road for most separation effects and causes to become apparent.  Blunt aft vehicle depend on organized separation and are a little harder to troubleshoot, but there are some good, simple rules to follow and some easy test methods to create stable recirculation behind a "Kamm" rear end.

Remember my motto:  Don't guess, TEST!