Aprilia goes V4...

Aprilia CEO Leo Mercanti has confirmed that his company will return to World
Superbike in 2007 with an all new model... a highly sophisticated 90 degree
1000cc V4 is currently under development...

Every time I ride Mr.RC45 I think about all of you out there... thumping away on
your V2s... buzzing along on your I4s... it just ain't fair I should be the only
one enjoying the advantages of a V4... thank goodness Aprilia is serious about
offering up a competitive V4 like Ducati's Desmosedici...

I predict that V4s are on the rise and soon there will be one in your future...
http://www.webbikeworld.com/aprilia/aprilia.htm

Larry L
94 RC45 #2
Have a wheelie NICE day...
Lean & Mean it in every corner of your life...
If it wasn't for us the fast lane would rust...
V4'S are music to the seat of my pants...
1952 De Havilland Chipmunk...
Yank and bank your brains loose...
http://members.ebay.com/aboutme/-xlax-/
http://home.comcast.net/~netters2/
http://www.fox302.com/index.pl?s=vg&user=netters2
http://www.reeky.org/gallery/xlax

 

I predict Larry will be posting this for years to come. Now that I think
about it, that is hindsight. Larry has been posting this for years already.
It is deja vu, all over again.

And you didn't mention the I3, popular amongst the Triumph crowd.

I predict there is a Briggs and Stratton in your future, or a Tecumseh.

Bryan

 

" This is like deja vu all over again." Yogi Berra

There were some V4s about 20 years ago or so. I had the US version
of one of this:
http://tinyurl.com/axoj2
A friend of mine had a 500 V4 Honda in the mid 70s if memory serves.

Dean

 

Bryan wrote:

I'm fond of my GL1200's smooth; quiet; and low, low, low center-of-gravity
horizontally-opposed-four.

 

You know some of us ride V-Fours and they are not attached to a sport
bike.

The V-Four is great for touring too.
--


Don
RCOS# 7
No Riding Today

2000 - Yamaha Venture Millenium Edition

 

He shoots! He scores!

Bryan

 

And Honda Racing went V5. If the V4 was so inherently superior,
you would think HRC would be not be wasting their time and money
on such an odd engine configuration as the V5.

 

I predict that fuel cells are on the rise and there
will soon be one coupled to an electric motor drive
in your future, if you live that long.

 

once i perfect the flux capaciter cellular anti hydrogen willbewas drive for
sport bikes i will rule the WORLD!!!!!!!!!!!!
rode a magna for awhile in the 80s it was cool.
i like my gl1500 just fine.
rode a 06 ultra classic. it handles ok for a big bike but i thought it was
falling apart the whole time.
and the shaker rider said my wing felt really smooth? i could barely hear
the stereo on that harley.

haha off to yosemite in the morning..........................Matt

 

Thats true... a person would think that.

However its like this with reciprocating mass... the less mass
the faster the part can change direction, and thats an
exponential function.. so that a 20% reduction in mass allows
for a much larger incease in piston and valve speed... and
that RPM incease produces a linear increase in horsepower per
cc. thats why they went to the 5 cyl. imo.... and for a
few other reasons I can only guess about not knowing the
crankshaft configuration, for instance engine balance issues
also supporting the higher RPM capability.

with higher piston speeds there are issues with ring wear and
ring float in the bores.. ring wear is mitigated by means of a
shorter stroke and larger bore, allowing more valve area in
relation to the displacement than a longer stroke engine.
Thinner rings in tigher lands eliminates float.


Why not a V-6 then? It may be that the V-5 crankshaft can
be built to nestle the twin pair more convieniently between
the outer two cyclinder journals on the 3 bank side.

.....this could be arranged to insure a power stroke phase
displacement driving force that allows another cyclinder to
see ignition earlier before top dead center than with another
configuration. That could be the middle cyl, of the three
cyl bank... firing out of phase with the other 4 on its own
journal... the outer two cyclinders on the same journal in
each bank arranged as with their V-4. the 5th cyl providing
in effect fly wheel inertia without the fly wheel.

Id bet that the fly wheel on the V-5 is 30% or more lighter
than with the V-4. that would allow the engine to rev
faster, and reduce the gyroscopic mass of the motor.
Reduced gyroscopic mass would also make the bike more
flickable.

I predict a serious edge for the V-5 in both handling, weight
and horsepower.


What would the downside be? Loss of tractability due to
smoother power to the rear wheel...


the reason HD twins have done so well on the dirt for instance
is the 370 degree spread between the power pulses to the rear
tire, giving it time to hook up with the dirt... that is
probably behind the advantages we see with ducati on some
tracks among other things. Twin and big singles have always
had that particular advantage, but suffer of course on net HP
due to lower RPM capability. Big singles do well in the dirt
for the same reason, 720 degrees between power pulses, allows
the rear wheel to stop and grab traction.


The V-5 will be smooth...too smooth for best advantage with
many riders. It will take some time to sort out tire
compounds and riding styles.

None the less I think the V-5 will dominate on longer smoother
tracks, run close or with an edge on most other tracks, and do
well on short tracks even as it suffers tractability...
because it will have gained net capability via less gyroscopic
engine mass, and lighter weight over all.

Lighter wt is a huge issue in turns... even 5 lbs is a lot...
Id bet their motor is at least 5 lbs lighter, and the fly
wheel/rotor at least 8 ounces lighter... 8 ounces at 20,000
RPM is a leverage arm on the frame over 100 lbs. thats
significant to say the least.

Complimenting that would be lighter wheels and lower profile
tires. Id suspect magnesium engine cases, titanium rods and
valves, and aluminum alloy heads,, all engine wear surfaces
will probably be diamond fused. (film you can get on eye
glasses these days)... the motor will probably run mineral not
synthetic oil, 5/15 wt or lighter due to better heat
dissipation, lower film coefficient necessary in close
tolerance high speed applications. I would not be surprised to
see a blend in the 3/10 range.







Phil Scott

 

Honda's V5 is a win at all cost strategy in MotoGp wars... however it's a dead
end engine architect as far as WSB rules are concerned... they stipulate the
maximum of 4 cylinders... ain't no way Honda can homologate the V5 legally...
and without a racing avenue... Honda can not justify the cost of tooling a V5 up
for production... that's why Honda's new 800cc MotoGp engine is a V3... you can
race a V3 in WSB...

Larry L
94 RC45 #2
Have a wheelie NICE day...
Lean & Mean it in every corner of your life...
If it wasn't for us the fast lane would rust...
V4'S are music to the seat of my pants...
1952 De Havilland Chipmunk...
Yank and bank your brains loose...
http://members.ebay.com/aboutme/-xlax-/
http://home.comcast.net/~netters2/
http://www.fox302.com/index.pl?s=vg&user=netters2
http://www.reeky.org/gallery/xlax

 

And you didn't mention the I3, popular amongst the Triumph crowd.

I didn't mention the shaker I3... it won't be as popular going up against
Yamaha's new V3 or Honda's new V3 anyway...

Larry L
94 RC45 #2
Have a wheelie NICE day...
Lean & Mean it in every corner of your life...
If it wasn't for us the fast lane would rust...
V4'S are music to the seat of my pants...
1952 De Havilland Chipmunk...
Yank and bank your brains loose...
http://members.ebay.com/aboutme/-xlax-/
http://home.comcast.net/~netters2/
http://www.fox302.com/index.pl?s=vg&user=netters2
http://www.reeky.org/gallery/xlax

 

I got me a V-4, and I like it a lot. Just out
of curiosity, was it exactly that you think
a V-4 does better than the I-4? My V-65 engine
delivers a lot of low end punch, but that's not
due being a V rather than an inline, is it?

http://www.people.cornell.edu/pages/hhh3/v65side.jpg


-

http://www.st911.org./

 

a V-4 does better than the I-4? My V-65 engine delivers a lot of low
end punch, but that's not due being a V rather than an inline, is it?
___________________________________________________________________________

Like a balanced twin, they don't buzz and produce linear power across
the rev range. With shorter strokes they can rev higher and put out
more power than twins. Important stuff to racers and posers, less
important to run of the mill riders.

 

thats close.

The actual situation is like this.... the V-4 has 3 too many
cylinders two of them facing the wrong direction... the i4 has
3 too many cylinders also, all of those facing the wrong
direction so its worse.

The V twin has only one too many cylinders so that it is a
much better and more sane choice in machinery.

However the most demanding of all motorcycle sports,
motocross with man and machine flying through the air 20' off
the ground sideways, and flat tracking predominantly with only
rare exceptions.... is only possible on the best machines
known to man, the single cylinder machine.





Phil Scott

 

I hafta agree.

And unless Lawrence of Califorina plans to slip on some more of that
invisible sand in a hot turn, he'll be around bemoaning the
preponderance of brushless electric motors (front and rear wheels
natch) made out of exotic ultralight alloys built into the wheel. With
computer controlled algorithim to adjust the slip angle and allow
everyone to approach what was once Valentino territory.

The biggest problem with fuel cell technology will be making noise and
annoying the planet. Therefore I suspect big speaker fetish to afflict
all future motorcycles so the squids and biker trash wannabees can
infest the neighborhood with their 1200 watt woofers.

"LOUD SYSTEMS SAVE LIVES!"

Of course BMW riders as always will clench their anal sphincters
tightly and espouse upon the virtues of quiet clean earth friendly
stealth fuel cell drive. Rather than place the motors in the wheel
like all other OEMs, they'll have two seven ton units horizontally
opposed dangling in the lower slipstream.

Cagers will have yet another excuse to mow us over. "Honest officer, I
couldn't hear him..."

Millions of Green Party Californians will commit mass suicide. Their
purpose on this planet obsoleted, there will be nothing more to whine
about all Woody Allen neurotic like. Therapists will resort to begging
for spare change in the street and living out of the back seat of
their 7-series BMW.

Because anyone with a modicum of class can tell you, whatever you do
you can't get rid of the BMW. What will the neighbors think!

 

the V twin is not a bad deal at all.... still however the
550cc machine the article discusses weighs in at 286 lbs...70
hp... its heavy, and for the dirt will not be as tractable as
a single.

The yamaha yz450 (a 4 stroke single) weighs in 65 lbs lighter
....a massive differnce on the dirt and of course as a single
along with others remains the only viable option on the US
professional motorcross circuit. In motard with its paved
section the V twin would have an advantage..but not on the
dirt.

Time will tell how the V twin plays out in motard. it it
stays heavy it will not last imo. A weekend on a 500cc
single close to 200 lbs on tight paved back roads will prove
that to a person. But still at 286 lbs and 70 hp the aprilla
is one hell of a bike...I am glad to see them doing it... it
will make a vastly better dual purpose bike that will also
cruize the super slab than a single.


Phil Scott

 

On Sun, 12 Feb 2006 10:02:52 -0900, "Robert Bolton"

[...] snip

The above paragraph is totally irrelevant on the whole. It has more to
due with the limitation in piston speed than ANYTHING related to torque.

No! Now read & try to comprehend the following.

Myth, Robert and here's why!

Torque is a function of the following in an internal combustion or
(piston) engine:

1) Displacement = ("bore"= pi times the radius squared) times the
"stroke" times the "number of cylinders" in cubic centimeters or cubic
inches, your choice.

2) Compression ratio.

3) Volumetric efficiency including such things as turbo or supercharger
boost.

4) Power potential of the fuel and this is where it gets complicated.

a) Diesel engines can tolerate more boost pressure due to their relative
immunity to octane (Diesel opposite or cetane) ratings and "faster [1])"
burning rate. (Low exhaust temp and as a side effect, better thermal
efficiency).
b) Gasoline engines are limited to ~14:1 CR on alcohol fuel. "Less" if
you turbo/supercharge them.
c) Gas powered singles are further limited in compression ratio because
they have a relatively large bore= flame burn time to the edge of the
cylinder before the secondary flame front or detonation occurs.

[1] Diesel fuel burns faster than gasoline in "feet per second". Hint:
Diesel fuel, not gasoline fuel is used in fertilizer bombs". However the
entire injection (CI=more like a blow torch or "stratified") process is
actually slower than the "stoichiometric" combustion phase of a SI
engine. However even considering this, Diesels have lower exhaust gas
temperatures, which would indicate a faster combustion process before
the exhaust valve or port is opened.

What about long stroke single cylinder, naturally aspirated, gasoline
engines?

They're most common in our sport of (Moto-motard/flat track bikes). Now,
because singles have larger/more massive reciprocating parts (pistons,
valves and so on) and therefore have limited "high RPM" operation, due
to these mass limitations. So.... they actually work better at low RPMs
due to higher relative gas velocity (remember those big single pistons
versus many-"Bannon you following"?) due to the relative smaller valve
area of a single compared to a twin, triple, four or at best 5 to 10
cylinder engines which see their best breathing at high revs and
actually suffer down low for several reasons beyond the scope of this
discussion (valve overlap for one) but there are many, many compromises
in engine designs. Also remember big singles are NOT as Phil says
tractable but quite the opposite due to the need for more massive
flywheel weighting.

Not to sound condescending but I think that this is about as DEEP as we
need go considering the mentality of these motorcycle news groups

In short, you're only talking about "effects", not "causation", Robert!

Bob Nixon
01 Sprint ST "RED" 52K
Chandler,AZ
http://bigrex.net/pictures

 

Both the long crank throw, and widely spaced power pulses
are key aspects of why big singles dominate on the
dirt...long, widely spaced power pulses.

re your flywheel comment.. the old long stroke motors had
huge fly wheels, but those were NOT putting power to the
ground, only maintaining momentum.. power only reached the
ground on the long power stroke .. spaced at 720 degrees. ..
as contrasted to every 90 degrees on some i4 configuations,
(two strokes) and 180 degrees for most 4 stroke i4's (except
those that fire two cyl at a time, then its net power stroke
is every 360 degrees).

So a 720 spacing is a huge deal for tractability... fly wheel
or not. the newer short stroke yz450 rev's high and has a
shorter power stroke, but less fly wheel, so it bites well
too.


On your issue of torque related to fuel and the number of
cylinders you are correct... long stroke and widely spaced
power pulses are a factor in net torque but not the prime
factors as you point out... when you go to more cylinders
and take fuel options into account.

Remaining though are the tractability issues... and
tractability is solely a function of how widely spaced the
engine power pulses are apart along with the net wt of the
machine and rubber etc.

Not to confuse...tractability with torque related to crank arm
and stroke issues...although they are closely related in some
important aspects.. the duration of the power pulse etc...but
not others as you pointed out in your multi cylinder comment.


Phil Scott

 

Not a V4? Why, Larry, why?