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H-D kills off more models ?
- Thread starter TK4
- Start date
TK4
Well-known member
How about 11,000 HP @ 9,500 rpm ? 20 Facts About Top Fuel Drag Racing Cars You Need To Know (thethings.com)
Trials
Well-known member
I like this one way better:
UMS 260cc Gas – 7 Cylinder Radial 4 Stroke Engine - CH-ignitions
The UMS 7-260 is a very reliable radial engines which uses gas fuel. UMS has a ton of experience building radial engines. It has brought more than 2000 engines to market so far. The design and construction are upper class leading to a outstanding realibility of these engines. They are easily...
ch-ignitions.com
A couple of things they didn't tell us that I find amazing
The blower on a top fuel car uses about 25% of the total output of the motor. If the motor makes 11,000HP, the induction uses 2,750HP... through that belt.
Watch the slicks on a top fueler go off the line. See how they fold up at the bottom? That reduces the gear ratio of the drive by as much as 25%. Low gear without a transmission!
Watch the slicks at the big end of the track. The centripedal force from all that RPM has made them almost twice the diameter. Increasing the final gear by as much as 33%, so it's like having a 4 speed.
The only way to shut down the motor at the big end is to kill the fuel. It's a diesel and has melted the ends of the sparkplugs when it gets there.
The car starts with SAE90 oil, and finishes a couple of seconds later with SAE10 oil.
Fuelies is peachy keen!
IIRC they also rebuild the engine under 10 minutes in between rounds
Sent from my iPhone using GTAMotorcycle.com mobile app
Eeek. Grabbing the hub of a spinning prop to stall out the 260cc engine would not have been my first choice.
Mad Mike
Well-known member
Years ago I saw a great great documentary that explored a few Harley design changes. Turns out chain driven cams and belt driven wheels were adopted mostly to reduce mechanical noise. Same to some degree for rubber mounting engines engine. Belt driven wheels and chain driven cams are costlier in production so it's not a cost thing.
EPA noise emission standards capture the sum of mechanical noise and exhaust noise. As Harley tunes to the hairy edge of EPA sound pollution guidelines, anything recovered in mechanical noise is transferrable to the exhaust noise budget.
All this mechanical noise is amplified by air cooling.
Water cooling will quieten down a Harley immensely
Chain drive cams are a LOT cheaper to manufacture. It will reduces the need for accuracy in the manufacturing process.
Gears have to be, more or less, dead on, or they lose efficiency, accuracy and make a ton of noise. If you make motors with different piston heights or strokes, each design has to have it's own unique gears set.
Chains/belts and sprockets? Close is good, throw in a tensioner.
Water cooling will quieten down a Harley immensely
Chain drive cams are a LOT cheaper to manufacture. It will reduces the need for accuracy in the manufacturing process.
Gears have to be, more or less, dead on, or they lose efficiency, accuracy and make a ton of noise. If you make motors with different piston heights or strokes, each design has to have it's own unique gears set.
Chains/belts and sprockets? Close is good, throw in a tensioner.
Roadghost
Well-known member
Bear in mind that California will require zero emissions in 14 years. That doesn't leave room for many more ICE redesigns. From a reliability standpoint, obviously gear drive is best, but I have no problems with belt or chain drive cams as long as the engine design allows for easy access and replacement. Those designs are perfectly reliable as long as the belt or chain is replaced at the recommended intervals.
TK4
Well-known member
IN MY OPINION -
Rewire must include a serious revamp of the product line, which they're only halfheartedly committed to. Lose the Sportsters - too long in the tooth, and they likely won't meet any future emissions regulations anyway. DO NOT kill the Street 500/750s, this powerplant can be the platform for future ADVs, standards, street trackers or dare I say it sport bikes - see XG750R. Quality must improve, no question, but its easier to start with a motor that's going forward, not stuck in the past. Use the Pan America (and I hope Bronx) as a gateway platform to a real Sportster replacement a la Indian Scout. Continue shrinking the Big Twins lineup - if it doesn't come with the stuff you want then look in the accessory catalogue or to the aftermarket. Keep working on affordable electrics. And lastly, get rid of the trikes - they just make you look bad.
BTW, the CEO has pulled all sales of H-D related paraphenalia from Amazon - good move !
Rewire must include a serious revamp of the product line, which they're only halfheartedly committed to. Lose the Sportsters - too long in the tooth, and they likely won't meet any future emissions regulations anyway. DO NOT kill the Street 500/750s, this powerplant can be the platform for future ADVs, standards, street trackers or dare I say it sport bikes - see XG750R. Quality must improve, no question, but its easier to start with a motor that's going forward, not stuck in the past. Use the Pan America (and I hope Bronx) as a gateway platform to a real Sportster replacement a la Indian Scout. Continue shrinking the Big Twins lineup - if it doesn't come with the stuff you want then look in the accessory catalogue or to the aftermarket. Keep working on affordable electrics. And lastly, get rid of the trikes - they just make you look bad.
BTW, the CEO has pulled all sales of H-D related paraphenalia from Amazon - good move !
Trials
Well-known member
Your chain tensioners are going to wear out before your chain does anyway.
Chain is made of steel and the tensioner is normally a chunk of plastic, the plastic is going to lose that battle every time.
One of the highest fail parts on a Harley engine is the primary chain tensioner and the torque compensator*
*(a torque cushion which is only required because their silly engine design has 2 lop-sided cylinders out of the 7 it would take to make it run smooth)
Chain is made of steel and the tensioner is normally a chunk of plastic, the plastic is going to lose that battle every time.
One of the highest fail parts on a Harley engine is the primary chain tensioner and the torque compensator*
*(a torque cushion which is only required because their silly engine design has 2 lop-sided cylinders out of the 7 it would take to make it run smooth)
TK4
Well-known member
Last summer I saw a Sportster that had such a badly worn out primary chain that it had started to saw its way through the shifter shaft. At the same time, the clutch basket (which houses the alternator on the backside) had walked around enough to tear out the windings so it wasn't charging. Admittedly it was an older machine, but stuff like this apparently happens all too often.
The conrods are attached to something that looks like a flower so they are all in one plane. Not sure what the proper name is.
EDIT:
Apparently it is called a spider bearing.
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Trials
Well-known member
brilliant eh
and the silly thing it was the radial engine that inspired them to make the 45 V-twin, and in all those years following H-D never got around to adding the rest of the cylinders,
possibly because it would have addressed the vibration, torque variations and moderate performance issues.
and the silly thing it was the radial engine that inspired them to make the 45 V-twin, and in all those years following H-D never got around to adding the rest of the cylinders,
possibly because it would have addressed the vibration, torque variations and moderate performance issues.
Packaging and cooling a radial engine in a bike are problems not easily solved. In wheel radial can work but your unsprung weight is ugly.brilliant eh
and the silly thing it was the radial engine that inspired them to make the 45 V-twin, and in all those years following H-D never got around to adding the rest of the cylinders,
They can also have a "master rod"
One rod connects to the crank, and the other rods connect to that "master"
One less bearing
The COOLEST part of those radial engines was the cam. Most ICE engines the cam runs at 1/2 crank speed , and in the same direction.
No one told the radial engine designers, they have some REALLY weird setups. almost all of them drive in the opposite direction to the crank, at 1/2 or 1/4 or 1/8 speed, some follow the back side of the cam.
NEATO!
A side by side twin (actually any inline multiple where the crank is 90 degrees to the drive line) has a side to side rocking vibration, called a rocking couple, as the forces are expressed on either side of the center line of the motor. Worse on a 180 motor than a 360 motor.
Vibrations "inline" with the crank throws are "primary" vibrations. (This is what "counter balance" shafts combat. They introduce an opposite vibration...sort of)
A "V" twin that shares a crank pin, like Harleys, don't have this rocking vibration. All these forces are inline with the crank throws. (Ever seen "the knife and fork" Harley rod arrangement? Look familiar?)
...and then we got the Norton Commando with Isolastic motor mounts... WHAT A JOKE... A BAD JOKE.
The motor is mounted in big rubber chunks, that are supposed to absorb all the rocking, then they limit the movement of those rubber mounts with three pivot points that only allow fore and aft movement (primary vibration) AND THEN THEY CONNECTED THE SWINGARM TO THIS HOT MESS!
.... yeah I'm working on a Commando.... trying to sort out the suspension... POS... what a stupid setup.
Mad Mike
Well-known member
I learned a lot about British engineering a long time ago. First by working on MGs, Triumphs and Jags, and later at a British electronics plant.
While working there I learned that in Britain "tenure was a big thing in engineering", so all new ideas came from the minds of old men.
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