Landracing Forum
Tech Information => Aerodynamics => Topic started by: speedrattle on July 29, 2018, 08:32:35 PM
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hey folks
i lurk here a lot but haven't posted. i'm looking for any and all suggestions on improving the aerodynamics of a naked 650 triumph i run in M/PG 650/4. we just got back from loring where the machine did extremely well, bumping the mile and the one-and-a-half mile record held by a good friend of mine to 130.935 and 134.287. we're going back in a month with some tweaked gearing and ignition timing to see if we can get 131 and 135.
all of the top three old british machines in this class are within about two miles an hour of each other, and we're not really looking at much more horsepower before we start blowing them up. so i'm looking for aero alternatives. my bike is a 1965 triumph bonneville, sort of, with a 1970 motor, sort of. i can't use any streamlining in front of the rider, although a 180-degree front fender is permitted. i'm allowed to use a seat with an aero shape behind my butt, so long as it doesn't go more than 3 inches back from the tire. here's what the machine looks like at the moment:
(https://i.imgur.com/ph1dHWll.png)
(https://i.imgur.com/94MALVkl.jpg)
right now i lie down with my chest on the top frame tube, with my head to the left and below the top triple clamp, level with the tanks. this gets my back down as low as i can, but i'm wondering if there are other things i might be thinking about.
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Tiger Racing front fender ---
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A straight side view of rider in full tuck position would be useful.
The original Bonneville tank, with the tunnel modified to mount lower maybe, would have to be better than flat-fronted cylinders.
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The down tubes in your exhaust are pretty draggy just hanging in the wind like that. Consider turning them
inboard then turn them down in the wind shadow of the front tire.
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you already mentioned the obvious - you need a tail section.
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3 spoke mag wheels with aero shape spokes. Wire wheels are pretty draggy.
Raise your seat position to flatten your back line. Don Sligger told me to "raise your butt" during Speedweek '69. I picked up 3-4 mph on the next run.
Clean up all the details. Everything air flows over has drag....wires, cables, anything at all. Before I was finished I was running the bikes with no opening in the fairing ahead of the engine. It was a lot less drag than flowing air over the parts!
Flat blade girder forks are a lot less drag than round tubes.
The tail is an "anything helps" deal. My 650 pushrod twin (gas engine) ran 164 with the tail and fairing. I dropped to 134 with the outer aero removed!
Hope this helps.
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My favorite Bonneville springer forks:
Rex
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Don Sliger?
Boy, you are old. Maybe you can tell some of these young'uns what he did – and when. Royal Enfield, really?
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http://www.landracing.com/index.php/component/content/article?id=271
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I did not know him well, but he was really nice and helpful to me. My favorite memory: I was in staging right behind him and had been struggling to get my 450 Honda above 120. He asked what I was doing and I told him I had just geared it "too high". I told him, "Don, dont fall down out there because if I cant get past 120 this time, I am going to keep right on going and ride home to Colorado!"
He laughed and said, "Jim, I am going to go real fast, and if I fall down, I'd appreciate it if you would run me over right away."
My favorite pic is him sitting under his parachute sun shade, working on the single engine bike (which put up a very solid fuel record the next day). Some folks don't know how tough those records we made were, back then. First, you ran as hard as you could to qualify...and first thing next morning you made two more runs, back to back, with no repair time in between. There were bikes that qualified ok, but didnt survive the actual record runs.
It was sure different.
He didnt fall down (close to 200) and my bike ran 124.65. That was the day Bert missed a shift and spun the windings on his Indian's mag. He and another fellow and I started up the mountain to strip "bell wire" from a plane crash magneto, but my little street bike couldnt make it up the silt. They rewound the mag that night and my Dad stayed up all night watching.
That week was a great experience for my Dad and I. I had arrived home from Nam on July 17th and all you salt flats people yanked me right out of the war mentality, and planted me on the path to a better life. Don is a small piece of the memory, but he was the right guy to meet, at that important moment.
Sorry for the long ramble...we get that way when we finally grow up and old.
Jim
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That's not a ramble. That's history and a truly great story. :cheers: :cheers: :cheers:
Thank-you JimL!
Pete
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Jim ramblings like that are gold :cheers:
We went half hearted searching for that wreck a few years ago when the salt was wet and we were bored in Wendover , think we were in the wrong area
crossed the saddle (dodgy when damp) and went left instead of i think right ?
road on the far side was cut up from rain anyway and were lucky to actually make it back
Back to the subject
smaller rider ;)
all the above esp raising your back and will add rear wheel discs
Friction reduction, ceramic bearings, brakes backed off , non o ring chain ,
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dang. been locked out of here for days. people, thank you for your replies. i'll try to take them one at a time.
A straight side view of rider in full tuck position would be useful.
The original Bonneville tank, with the tunnel modified to mount lower maybe, would have to be better than flat-fronted cylinders.
i was using an old trident tank at first, but it was so wide i couldn't get my head down, and had to just rest my chin on top. with the tube tanks set below the frame, i can bend down to where i'm level with the triples trees:
(https://i.imgur.com/CxQT4xXl.png)
(https://i.imgur.com/CedD4ncl.png)
forgot to tell my daughter about persepctive, so you can't really see the wind shadow on the straight-on photo. lol, she can't hold a camera level, either.
i don't kno whether the shape of the tanks is important, as they're pretty well masked by the tach and the front forks. i can't make them smaller because they have to hold five liters, and i'm right there.
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Tiger Racing front fender ---
i'm running in modified, so while i can use a front fender, even one that flares in the fork tubes, it might get questionable with any aero shapes molded in. airtech makes this busa fender, which is getting closer, but i'm running a 19-inch front wheel, 110/90-19
(https://i.imgur.com/AJvnMBVl.png)
i'm looking for something like that that will fit bewteen the fork legs.
you already mentioned the obvious - you need a tail section.
i can legally add a kamm tail seat, and for later next year i'm seriously considering it. there's a guy running an 850 commando in MPS, who goes 150-plus with this gigantic box behind his butt:
(https://i.imgur.com/iYtLFnQl.jpg)
but i want to do everything i can with the machine before i start adding bodywork, mostly because i'm chasing a 139 mph 650 record set by a guy on gasoline at bonneville without any bodywork at all. i'd like to see if i can get there.
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The down tubes in your exhaust are pretty draggy just hanging in the wind like that. Consider turning them
inboard then turn them down in the wind shadow of the front tire.
i stuck them way out that way from the head to clear the magneto, then kept them out to the sides so i could add a megaphone that would clear the footpegs.
but i'm not going to use a megaphone after all, so i'll take your advice and build a new set this winter. this motor runs best with the pipes 36-inches long, and that would truncate them right about at the same position, far enough in front of the rear tire not to annoy the safety guys.
not much room there between the magneto and the wheel, but i should be able to do something.
(https://i.imgur.com/kaxzpR8l.jpg)
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JimL's ramblings about Don Slinger reminded me of when visiting the National Motorcycle Museum in Solihull UK, thay had Don's twin engine 1500cc Royal Enfield bike on display,, in 1970 at Bonneville the thing set a class record at 194.726,, apparently it was the "first" naked bike to exceed 200mph at 203.16 8-)
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smaller rider ;)
all the above esp raising your back and will add rear wheel discs
Friction reduction, ceramic bearings, brakes backed off , non o ring chain ,
my number-one daughter weighs 107 pounds. we're going to start her on a 300 ninja next year, i hope. i'm likely going to switch to cast wheels sometime.
i know nothing about ceramic bearings. why are they better?
3 spoke mag wheels with aero shape spokes. Wire wheels are pretty draggy.
Raise your seat position to flatten your back line. Don Sligger told me to "raise your butt" during Speedweek '69. I picked up 3-4 mph on the next run.
Clean up all the details. Everything air flows over has drag....wires, cables, anything at all. Before I was finished I was running the bikes with no opening in the fairing ahead of the engine. It was a lot less drag than flowing air over the parts!
Flat blade girder forks are a lot less drag than round tubes.
The tail is an "anything helps" deal. My 650 pushrod twin (gas engine) ran 164 with the tail and fairing. I dropped to 134 with the outer aero removed!
Hope this helps.
thanks. everything helps.
i'm looking at cast wheels from something like a 300 ninja. they're 17 inches, which is good, and about the same width as the old dunlop rims i'm running now. i'd have to adapt a disc brake in the back, but i don't need a front brake at all.
i'll be messing with riding position next month. i reinforced the pegs so i can stand up on them, and i tried it out last month. i was messing with pipes, jets, and ignition timing at the same time, though, and didn't pay any attention as to whether it was any better. but i've heard that making a wind tunnel through your legs helps close up the turbulence behind the rider. is that true?
My 650 pushrod twin (gas engine) ran 164 with the tail and fairing. I dropped to 134 . . .
i'm intrigued. what exactly was that? i know a guy who does 166 on his 650 BSA, but he uses a turbo to get there.
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Thanx JimL for your comments!
"goes 150-plus with this gigantic tail section" – It's probably not as gigantic as yours.
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JimL's ramblings about Don Slinger reminded me of when visiting the National Motorcycle Museum in Solihull UK, thay had Don's twin engine 1500cc Royal Enfield bike on display,, in 1970 at Bonneville the thing set a class record at 194.726,, apparently it was the "first" naked bike to exceed 200mph at 203.16 8-)
that machine is famous. i didn't know it ended up in the UK. is it still there?
a friend of mine with the second-fastest 650 has also built this. he was first-fastest until last month, but is planning on coming back.
(https://i.imgur.com/kOjX6lAl.png)
it ran one time last summer, and then ate a crank seal and lost pressure on one motor. but he runs an oil gauge, unlike everybody else, so the rider shut it down without any damage. did 141 on its first and only run. i'm waiting to see it when they bring it back.
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Before I finished the hobby, I thought about building an "ultimate" open bike....just for the fun of the challenge. My pushrod Honda V-twins were such a wide engine that I never went onward.
The whole idea was that EVERYTHING has to have air flow across it when you are going fast. Even things that are out of the direct airflow are still creating some air drag that adds to the total.
Those notes on ceramic bearings and such are very good. I did go with those on my bike, and every little thing helps.
One of the ideas I had, which would aid aero without adding out-of-rule items, was to install the battery/box as low as possible just ahead of the rear tire (inline mounted). There is a hard, high pressure area in front of the tire because it drags air around with it....and throws it into the oncoming air ahead of that tire. That concept is why so many modern cars have spats hanging down in front of the tires. Aero drag improvements help the mpg ratings and the manufacturers use those details.
When we prepared the Bonneville Prius (in 2004) with Car & Driver, we were told by Toyota engineers to lower the car until the spats could just touch the ground. They knew very well how much drag a tire can create.
In the bar cables could reduce a little drag, especially it the bars are not round section.
Anything that air flows across should have sharp rear corners (teardrop idea is great, but doesn't really work on a short bike). Look at the new cars and you see more sharp corners at the back. The whole principal of Kamm is a clean break. As proof of little things adding up, look at the top of pickup tailgates, these days. They all have added top width, sharp corner, and tuck-in for better air release of the high pressure stream that dives off the top of the roof. Those folks are good engineers and we should all pay attention to what they are learning. The latest Tacoma has air straighteners to keep airflow under the mirrors from tumbling through the front door handle.
Everything can make a small difference. You could really have fun with your project and perhaps open a new chapter in un-streamlined bikes!
Good luck and success, while you go forward.
JimL
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Everything can make a small difference. You could really have fun with your project and perhaps open a new chapter in un-streamlined bikes!
i'll still be playing follow the leader for some time. i currently have the fastest production-framed triumph in the running, but there is a faster one running in altered that might be within reach before too long:
(https://i.imgur.com/DgCMf2sl.png)
^^^this 650 triumph went 139 on gasoline and 175 on nitromethane. 139 mph on any naked machine with a naturally-aspirated gas triumph motor is something to be proud of.
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It was 2010 when I was there, not sure if its still on display,, I have some photos that I tried putting up here but this site is telling me thay are too large at over 500kb :|
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Re: riding position. I would experiment a bit, try keeping your head centered (just make sure you can see where you're going!) then raising your back, etc. Hopefully there will be no shortage of runs available to experiment. Did you try a different helmet (one without the lip)?
I've been told that ceramic bearings make a difference at 200 mph, I imagine the impact would be more significant at lower speeds. I don't know if anybody has ever made back-to-back runs in an effort to try to quantify. Wheel bearings are an obvious choice but I've also heard of guys changing transmission bearings.
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Seems like a clever guy could test helmet and riding positions and more at little or no expense with coast-down testing.
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Balanced aero on a motorcycle is more important than we think. Anyone who has ridden in side winds notices that the bike loses a lot of power. The reason goes back to the basic rule that: HP = Torque x RPM divided by 5252.
If you have to lean the bike (even a little bit) to keep going straight, you must apply torque into the handlebars to counter the gyroscopic precession trying to turn the front wheel into the lean. There is absolutely NO way to counter this effect if you are riding on a planet with gravity.
The amount of power absorption is pretty surprising, and explains why side-wind runs at Bonneville are really lousy for our bikes.
Let's imagine you are having to make a 5 pound push into the right bar (and a 5 pound pull on the left), to keep going straight while leaned. If your bar length were 12" it means you are absorbing 10 lb-ft at the tire contact patch to hold your course.
If you have an engine that makes 50 lb-ft of torque at 5252 RPM, you just sucked up 10 horsepower with your handlebars, if that is the exact rpm you are riding. I have had runs at Bonneville that I was pushing/pulling on the handlebar with a LOT of pressure, trying to hold my line. The bike really slows down.....far enough that I have had to downshift to try to recover. I have pushed the bars far enough to feel the front tire break loose and slide across the course.
That really ruins your run speed.
I had a couple years that the bike was always requiring handlebar pressure to run straight, in no wind conditions. I reworked the fairing mounts to get both sides in balance....the bike was then easy to ride and went faster.
Food for thought.....and sometimes you can make some decisions based on the NWS isobar map predictions for the day. When the isobars for the salt flats area are wide, it is time to make your runs. It seems like it is just impossible to cover all the bases, but you must keep thinking, "everything matters".
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"everything matters"
Actually i just realised were all talking Bonneville and you run mile events
if you get the chance, go to the salt . A mile is not long enough to try body position changes and see a result
On the salt everything has a visible reaction, just watch the tach , it tells all
think small, knees in elbows in toes in , bum up , head down , can you creep your hands along the bars a little more , lots of time so test it all
I run turbo bikes, harder to tell this sort of stuff , but back in 05 a mate let me take his NA bike for a run , i learnt so much more on that 1 run than i would have in 3 or 4 years of wheelspinning and fishtailing the turbo
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Re: riding position. I would experiment a bit, try keeping your head centered (just make sure you can see where you're going!) then raising your back, etc. Hopefully there will be no shortage of runs available to experiment. Did you try a different helmet (one without the lip)?
centering my head means i have to rest my chin on the top tube, way above the triple tree in the wind. ducking down means my head creates a wind shadow that conceals some of the rest of my body. i've run older-style bell helmets that just bounced from side to side at speed. this one with the lip actually has no discernable buffetting, so i'm guessing they got it right. smooth as glass at speed, rather thnanknocking my head back and forth. the shoei helmets have a kamm profile, and i'm look at the budget for one of those. my bell is getting chewed up from grinding against the fork tubes.
I've been told that ceramic bearings make a difference at 200 mph, I imagine the impact would be more significant at lower speeds. I don't know if anybody has ever made back-to-back runs in an effort to try to quantify. Wheel bearings are an obvious choice but I've also heard of guys changing transmission bearings.
i'm looking at wheel bearings for the winter rebuild, along with all the other small increment stuff. dunno about transmission bearings. the layshaft runs in wet needles, so i'd only get to change out the mainshaft ball and roller. maybe it would be something.
did you run something up there last month? i was busy and didn't have much time to talk to people.
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Seems like a clever guy could test helmet and riding positions and more at little or no expense with coast-down testing.
i wish i could. appalachian ohio doesn't have a lot of sweeping downgrades. that's the main obstacle. but maybe i could figure something out. the race bike isn't even barely street-legal, but i can fake head and tailights.
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Food for thought.....and sometimes you can make some decisions based on the NWS isobar map predictions for the day. When the isobars for the salt flats area are wide, it is time to make your runs. It seems like it is just impossible to cover all the bases, but you must keep thinking, "everything matters".
i run whenever i can, make notes of the conditions, and then try to make sense of it afterwards. the fastest runs at loring in july were the last day, when there was a seven mph tail wind and the relative air density was 105, highest of all four days. all our runs are in one direction, one time, so that really makes a difference. when the wind is in your face, everything sucks.
but at loring, we're looking at a 12,000-foot runway, the longest straight paved race course in the world. if the wind is right, and your machine is right, you can do very well.
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"everything matters"
Actually i just realised were all talking Bonneville and you run mile events
if you get the chance, go to the salt . A mile is not long enough to try body position changes and see a result
On the salt everything has a visible reaction, just watch the tach , it tells all
think small, knees in elbows in toes in , bum up , head down , can you creep your hands along the bars a little more , lots of time so test it all
I run turbo bikes, harder to tell this sort of stuff , but back in 05 a mate let me take his NA bike for a run , i learnt so much more on that 1 run than i would have in 3 or 4 years of wheelspinning and fishtailing the turbo
i'd love to do bonneville, but it's so expensive for me to get there-- 1920 miles-- that i want to do everything i can on the mile events in the east before i spend the money. i used to live in california, but that was a lifetime ago.
the difference with the short and long events is just as you say-- i don't have time to change things and watch the tach, i have to be right the first time or i'm slow. still, i have 1.5 miles to get up to speed, even though i don't get to run a flying mile at the end.
interesting that you learnt as much as that on a slow bike. my machine is slow by modern standards-- 130 mph or so-- which means i live and die by the wind, not by horsepower. i'm barely accelerating at the mile, and pick up four mph by 1.5. at that point it's all wind.
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1920 miles? Is that all......it’s around 6000 if not more for me. Fly London to LA ....then pick the car up and tow to Bonneville. Lol. It’s worth every cent.
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And 8268.5 miles for me , made the trip for 10 yrs this season will be 11
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Kevin,
Although there's no substitute for going to the Salt Flats during an event for new ideas, you can learn a lot just from the photos that are posted by Scooter Grubb (https://www.scootershoots.com/BUBMotorcycleSpeedTrials/2014-Bonneville-Motorcycle-Spe/) and Phil Hawkins (http://ishootfromthehip.com/contact.html) as well as the photo gallery on this site.
Tom
P.S. For example, Scooter's BMST photos, 2014, page 17, photo 337
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And 8268.5 miles for me , made the trip for 10 yrs this season will be 11
1920 miles? Is that all......it’s around 6000 if not more for me. Fly London to LA ....then pick the car up and tow to Bonneville. Lol. It’s worth every cent.
it's worth it, but that's simply more money than i have, worth it or not. i've got two kids in college and three more headed in. but if i strike the lottery i'll be there.
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The rules state that streamlining is anything IN FRONT of the Rider that acts to guide the air around the bike. How about a nice belly pan that goes from the front of the engine to the rear where a batwing guides the air around the tire ? NASCAR teams had lots of neat ideas such as oval exhausts and very wide flat bottom oil pans. Rules now do not allow anything. Much more fun in the old days . LSL
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Re: riding position. I would experiment a bit, try keeping your head centered (just make sure you can see where you're going!) then raising your back, etc. Hopefully there will be no shortage of runs available to experiment. Did you try a different helmet (one without the lip)?
centering my head means i have to rest my chin on the top tube, way above the triple tree in the wind. ducking down means my head creates a wind shadow that conceals some of the rest of my body. i've run older-style bell helmets that just bounced from side to side at speed. this one with the lip actually has no discernable buffetting, so i'm guessing they got it right. smooth as glass at speed, rather thnanknocking my head back and forth. the shoei helmets have a kamm profile, and i'm look at the budget for one of those. my bell is getting chewed up from grinding against the fork tubes.
I've been told that ceramic bearings make a difference at 200 mph, I imagine the impact would be more significant at lower speeds. I don't know if anybody has ever made back-to-back runs in an effort to try to quantify. Wheel bearings are an obvious choice but I've also heard of guys changing transmission bearings.
i'm looking at wheel bearings for the winter rebuild, along with all the other small increment stuff. dunno about transmission bearings. the layshaft runs in wet needles, so i'd only get to change out the mainshaft ball and roller. maybe it would be something.
did you run something up there last month? i was busy and didn't have much time to talk to people.
I guess my suggestion was that actually trying the alternative position would prove your assumption that your current position was better. You know what they say about assumptions... I ran the electric 'Busa.
Sent from my MotoE2(4G-LTE) using Tapatalk
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I guess my suggestion was that actually trying the alternative position would prove your assumption that your current position was better. You know what they say about assumptions... I ran the electric 'Busa.
yo!
i talked with you on the line about the voltage you were running on your bike. wonderful machine.
on positions, i don't know what is better, or what is worse. have to look at the timing slips. i will test it.
currently broke-back-butt-in-the-air seems effective, just not aesthetic.
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The rules state that streamlining is anything IN FRONT of the Rider that acts to guide the air around the bike. How about a nice belly pan that goes from the front of the engine to the rear where a batwing guides the air around the tire ? NASCAR teams had lots of neat ideas such as oval exhausts and very wide flat bottom oil pans. Rules now do not allow anything. Much more fun in the old days . LSL
this next meet is where i see what i can do without bodywork.
for next time, i'll show up with a kamm boxx, a fender, a bellypan to test. . .
dunno.
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the totally naked machine did well.
133.002 in the standing start mile, and 135.259 in the standing start mile-and-a-half.
no aero aids on it all, except my fat butt stuck up in the air.
looking for three-spoke 17-inch cast wheels now.
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old GSX750 wheels. got two of them:
(https://i.imgur.com/osarMcdl.jpg)
the front will go in with just spacers.
17 x 3.00 inches. goodyear says their 2.5-inch frontrunners will fit just fine.
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That's a good find! Those spokes look like good aero. And being able to use an actual LSR tire is a plus.
Don
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well, now i have a question. i was planning on fitting these front and rear, but i just had a friend tell me that goodyear front runners aren't legal in SCTA for a drive tire.
is that correct?
alternatives in this size are hooziers and mickey thompsons, who i haven't spoken with. it has never occurred to me to ask about drive wheel applications for one of these. i'm not going to be putting more than 65 hp through it, and not more than 140mph, ever.
goodyear said that their 17x2.5-inch front runners aren't speed-rated (he said, we didn't bother . . . ), but the 17x4-inch tires are labelled for 300 mph.
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Been my observation that the "Front Runner" term is loosely used when applied to the Goodyear tires. My understanding that the same molds are used for Drag Fronts and LSR tires. Internal construction is different between the two. The actual tire model number is what counts when they are considered for specific applications, speeds, driven or not, etc.
Ed
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old GSX750 wheels. got two of them:
(https://i.imgur.com/osarMcdl.jpg)
the front will go in with just spacers.
17 x 3.00 inches. goodyear says their 2.5-inch frontrunners will fit just fine.
I wish they would say that to the SCTA :-(
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well, looks like andy cox has them on his 68 norton atlas. 17 -inch wheels, with tubes, and he ran 154 on them.
(https://www.accessnorton.com/media/bonneville-2018.172/full)
clearly i need to make some telephone calls.
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I agree, the teardrop requires greater transitional length to work.
IIRC the Kamm principle:
The rear extends back @ 14 degree angle until the X-area is 50% of the original cross section, then cut off flush. No radius, corner, reducing taper.
The flaw: Kamm uses the largest X-section of the car, not just the bike tail, so it can't be translated. If it work, it just reduces the drag of the tail, not the bike.
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I agree, the teardrop requires greater transitional length to work.
IIRC the Kamm principle:
The rear extends back @ 14 degree angle until the X-area is 50% of the original cross section, then cut off flush. No radius, corner, reducing taper.
The flaw: Kamm uses the largest X-section of the car, not just the bike tail, so it can't be translated. If it work, it just reduces the drag of the tail, not the bike.
that seems to make sense. on a tucked-in rider, the slipstream detaches right about the middle of the rider's back. for the kamm tail to work, the air would have to remain attached to the rider all the way back to where the tail begins, else you would fair in to the rider's butt. not impossible on a partial streamliner, but harder on a naked machine:
(https://i.imgur.com/vR3DoUnl.png)
https://www.youtube.com/watch?v=zG8Htax6_Og
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I did not know him well, but he was really nice and helpful to me. My favorite memory: I was in staging right behind him and had been struggling to get my 450 Honda above 120. He asked what I was doing and I told him I had just geared it "too high". I told him, "Don, dont fall down out there because if I cant get past 120 this time, I am going to keep right on going and ride home to Colorado!"
He laughed and said, "Jim, I am going to go real fast, and if I fall down, I'd appreciate it if you would run me over right away."
My favorite pic is him sitting under his parachute sun shade, working on the single engine bike (which put up a very solid fuel record the next day). Some folks don't know how tough those records we made were, back then. First, you ran as hard as you could to qualify...and first thing next morning you made two more runs, back to back, with no repair time in between. There were bikes that qualified ok, but didnt survive the actual record runs.
It was sure different.
He didnt fall down (close to 200) and my bike ran 124.65. That was the day Bert missed a shift and spun the windings on his Indian's mag. He and another fellow and I started up the mountain to strip "bell wire" from a plane crash magneto, but my little street bike couldnt make it up the silt. They rewound the mag that night and my Dad stayed up all night watching.
That week was a great experience for my Dad and I. I had arrived home from Nam on July 17th and all you salt flats people yanked me right out of the war mentality, and planted me on the path to a better life. Don is a small piece of the memory, but he was the right guy to meet, at that important moment.
Sorry for the long ramble...we get that way when we finally grow up and old.
Jim
👍👍👍👍👍
Great story. Thanks Jim.
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Being a noob to LSR aero, but not totally lacking in analytical thinking,
I have a question:
In the Kolb 125 video, it looks to me like the helmet sticking up above the fairing is increasing turbulence.
wouldn't it be better to be tucked completely behind the windscreen?
would a taller hump on the leathers be a benefit?
If so..... why wouldn't they just build the bodywork tall enough to hide behind?
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The rules state that streamlining is anything IN FRONT of the Rider that acts to guide the air around the bike. How about a nice belly pan that goes from the front of the engine to the rear where a batwing guides the air around the tire ? NASCAR teams had lots of neat ideas such as oval exhausts and very wide flat bottom oil pans. Rules now do not allow anything. Much more fun in the old days . LSL
I was wondering about rear wheel covers, do you think they might work better than 3 spoke?
I know that Ducati, and the World Superbike series have been testing them.
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I was wondering about rear wheel covers, do you think they might work better than 3 spoke?
I know that Ducati, and the World Superbike series have been testing them.
some people running machines like mine use them
(https://i.imgur.com/CJJhkTfl.png)
complete covers are legal for the rear, in front they have to leave 20 percent empty, i think
would be easy to adapt to the cast wheels, once they're fitted.
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Being a noob to LSR aero, but not totally lacking in analytical thinking,
I have a question:
In the Kolb 125 video, it looks to me like the helmet sticking up above the fairing is increasing turbulence.
wouldn't it be better to be tucked completely behind the windscreen?
would a taller hump on the leathers be a benefit?
If so..... why wouldn't they just build the bodywork tall enough to hide behind?
i don't know why they left the helmet sticking up. if you look at the kolb video, there's quite a bit of turbulence all over close to the rider, maybe four inches everywhere. if they made the cutouts smaller all around there would be less of that. this 1950's triumph 650 goes 180, so far, and the rider is completely shielded when he's in position:
(https://i.imgur.com/ra0rz50l.png)
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well, we'll see what the brandy-new aero wheels do in about a week, in loring, maine.
(https://i.imgur.com/vDS8gZCl.jpg)
these are both front wheels off a 1990 GSX 750 suzuki, that came with dual disc brakes in the front. i have the front wheel mounted to mongrel triumph forks without a brake, and the rear wheel has a stock suzuki disc on one side and a sprocket bolted to the disc mounting bolts on the other.
the 17-inch suzuki wheels and goodyear front runner tires are set up to give a couple of inches of ground clearance at full bump, so frontal area is down a bit. the 2.5-inch tires also reduce the contact patch. dunno what effect the reduced volume under the chassis might have.
didn't have time to change the pipes. i'll make new ones for autumn that curve in and go under the motor.
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well, we'll see what the brandy-new aero wheels do in about a week, in loring, maine.
And the results are????
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lol
i'm sorry.
this has been a hell of a year.
in july 2019 i blew up at the mile at 131 mph. one of the ARP rod bolts loosened up and let go.
(https://i.imgur.com/Ot1tzzhl.jpg)
(https://i.imgur.com/LZuSRGEl.jpg)
(https://i.imgur.com/MNxRXx5l.jpg)
the rod parting surface was . . . perfect, but three torques on the bolts were too many, even though i used a stretch gauge. never again. once use only, from now on.
saved the billet crank with a 20-under regrind, new cases, new rods, new pistons, two new valves and a guide, some re-working of the combustion chamber on one side, then july was cancelled and back to the races in september 2020.
only 130 mph.
but nobody else at loring was fast either. the 200mph guys were shutting down at 175 because of a fierce cross wind that just wouldn't go away. i worked my machine pretty hard, but 130 was as fast as it would go this time around. so i'm back at the home ranch and looking for one percent tweaks.
but the daughter set a record in P/PP-250/4 on a 2007 ninja at 103:
(https://i.imgur.com/SWt0QL7l.jpg)
and the other daughter came close at 102
(https://i.imgur.com/u0vZvDtl.jpg)
but the chassis was perfect, hands-off at anything under a hundred. looking to clean up the rough bits now, oil tank and anything sticking out into the wind.
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acting on teh assumption that themotor is okay for the moment, maybe 60 horsepower, i'm going to clean up the chassis aero:
-- box in where the round blue oil tank is, maybe build a tank to fill that space and also fair in the front of the rear wheel, something like the old manx builders did.
(https://i.imgur.com/vDS8gZCl.jpg)
(http://www.scalemotorcars.com/gallery/data/737/PICT1997.jpg)
except fold in around the front of the rear wheel . . .
-- bring the pipes into the centerline of the bike behind the front wheel, run them directly underneath and dump there. their length is fixed, really, two inches longer or shorter slow the machine 4 mph, and so i don't know what that turbulence will do directly under the motor.
-- tuck in everything that can be tucked in, cables in, number plates ditched (i'll just stick numbers on the box
-- anything else i can think of
a big lump in the front is my head. my helmet expeires after this coming year, and i'd like to try out a helmet that's built with aero in mind. lots of them claim turbulence reduction, and the one i have now is cvastly better than the bells i've been wearing for decades. but maybe something better is around.
dunno. but i have time to think
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. . . and install wheel covers. i can do the rear 100 percent, front needs to be 25 percent exposed, i think. easy to do because the katana wheels have a hole in each spoke.
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Speaking of wheel covers... Did you know that Amazon sells them? They advertise their wheel covers under the code name "17 Inch Pizza Pans". I have a 17" pan on the left and 18" on the right. Heavy duty aluminum too.
Don
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holy shit
ive been staring at those wheels trying to figure out the simplest way to cover them and i believe that you have the best answer. and they come in one-inch increments, too.
what are you using for fasteners on those? they look like a quick release
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The fasteners are merely stainless flat head hex screws. As you can see, I riveted reinforcement metal where the screw goes into the cover. The two sides are screwed into an aluminum threaded rod that spaces the covers so that they fit tight against the wheel. They will not slide around as the spacer rods go through a opening in the wheel spokes and are zip tied with SS zip ties. When I get to final assembly I will Locktite everything. I did static balance the wheel and it did not need much weight.
The oval opening is situated over the tire valve. I have an air hose extension that goes in there to fill the tire. Tape can go over the opening.
Don
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well, i can't take credit for foresight, but the 90's GSX750 wheels i'm using have a hole in each spoke perfectly positioned for a threaded rod or even just a through-bolt.
(https://i.imgur.com/lSSPX99l.jpg)
i don't know why suzuki put them there but i know what i'll be using them for.
the pizza pan idea is brilliant. it reminds me of the old british road racers who used to scrounge metal biscuit-tin lids to use for number plates.
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Suzuki knew that you wanted wheel covers. That why they put the holes there.
Actually I think those may be drain holes for water that may get into the spokes.
Also, consider ordering 4 pizza pans unless you are one of those who can get things perfect on the first try! Now I have spare pizza pans with holes in them.
Don
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There is also a pizza pan separator. This is a flat round, without the rolled edge. Not going to be as rigid, but makes for a flush cover on a spoke rim. And there happened to be a size that was a perfect fit for an 18" rim (I think 19?). For the center holes I clamped the pan to a sheet of 3/4" ply and used a Dremel mounted on a circle cutting attachment. I drilled the edge of the drum between spoke holes and mounted the brake side cover with 6 screws. The sprocket side cover is attached to that cover with three spacers and screws spaced about halfway out to the rim.
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Kevin,
Just remember that with a disc brake, you have to get a disc that is small enough to hug the spokes. Otherwise, you won't be able to fit the brake caliber over the disc. Here are the two versions, one on a drum brake, and one on the disc brake wheel. Can't seem to post photos today.
Tom,
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I had my covers made from flat-sheet alloy............water jetted to fit. Then attached weather-stripping to the rim to keep rattles and vibration to a minimum. You could use any rear wheel with a small drum-brake to keep things simple.
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hmmm
thank you doc and scrambler, the pizza pan separators are certainly less bulk than the pans, and buying 24" x 24" 1/16 5052 aluminum is a possibility.
but tom, your point about the brakes is critical, because the caliper is going to need some re-thinking. i'm using a bog-standard 1970's triumph lockheed caliper on the katana disc that came with the wheel, and it comes within about 1/4-inch of the spokes. hard to see here in the dim warehouse, but arranging clearance for the caliper is going to need a bit more space.
(https://i.imgur.com/kg2iJ4n.jpg)
no issues on the sprocket side
(https://i.imgur.com/NCTyhiJ.jpg)
looking right down the disc the close quarters on the caliper shows up better.
(https://i.imgur.com/s9yw5Ybl.jpg)
no interference with the holes in the spokes-- they're abouut two full inches outboard of the caliper.
the only reason ici s went with this caliper is that it's the one i had on the forks when i ran a front brake. a physically smaller caliper on the disc or an offset disc would pull away from the wheel enough to get clearance, i think. or one with less thickness on the disc side. the mount is just a triangular piece of aluminum with three holes in it.
i don't need much of a brake on this. the only time it gets used is unloading and stopping in the pits
(https://i.imgur.com/4StOyZCl.jpg)
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question:
would running a full disc on just the drive side and not the caliper side be of any/much benefit?
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question:
would running a full disc on just the drive side and not the caliper side be of any/much benefit?
No idea if it does or doesn't but that's what I'm doing because of clearance issues.
Don
Also, I'm using an aluminum catch pan for a water heater, because I have it.
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Speedrattle
Look for a rear caliper of a late model sports bike. They are usually
a single piston with a floating caliper. If you can make it work you
will save a lot of room on the inside.
the disc you have fitted is a front disc. Maybe a smaller rear disc could
be adapted to help with clearence.
cheers Bones
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Speedrattle, I have two fenders that might work for you. They were made for a narrow glide Harley front end with a 19 inch wheel. I can't post pictures so if you're interested give me a call. 904-6 two two-six 38 one Thanks, rickr
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bones, i spent some time on ebay last night looking at smaller calipers, and spent fourteen bucks on this (free shipping!) to do some experimenting
(https://i.imgur.com/3rzJjRFl.png)
(https://i.imgur.com/2zfbXq2l.png)
(https://i.imgur.com/GQZIjYyl.png?1)
rear caliper from a 2007 kawasaki ninja 250. two piston, but floating, as you suggest. looks a lot smaller on the inside than the lockheed fixed caliper i have now.
i]m using the huge front suzuki rotor because that's a front wheel on the back, and i knew it would fit. i don't have a junk yard anywhere near me to go measure things, sadly, so i end up guessing from pictures.
rick, thank you. i'll give you a call.
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I'll try again.
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Here's one of the wheel before fitting the wheel disc. The disc is mounted directly against the inner rim and gives just enough clearance to fit the caliper.
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i see what you're saying. internal clearance is the issue. i just went down to the shop and measured, and my fixed lockheed caliper is two full inches thick between the outboard surface of the rotor and the inboard bolt head mounting the caliper. dual acting pistons, so that distance is fixed.
my daughters race a 2007 250 ninja, which is why i thought of that little caliper. i measured the one on their bike, and its only 1.1 inches for the same distance. new pads, so that will be the maximum extension inboard. i think that will give me the clearance there i need. also, there are two lips on the katana rim, one along the outer bead, and another just outboard of the spokes. i think i can set a pizza separator tray right against the spokes on that inner rim and still clear the caliper.