Wednesday, January 15, 2020

Structured Light Scanning is Cool!

After the caliper and plug technique used for the crankcase centers, watching Peter scan the cylinder head, throttle body, exhaust downtube, and oil pickup tube was like peeking into some wonderful future where all you had to do was press a button and presto, scan!

Actually, its nothing like 'press a button and presto', not much is.  Peter has spent a lot of time and effort getting his scanning setup to provide repeatable results.  Wikipedia has a bunch of details on the process here.  The short of it is you have a projector and two cameras that are in a fixed orientation.  The projector projects a pattern of changing scale onto the object to be scanned.  The two cameras each see a different perspective of the pattern projected on the surface of the scanee, and through many billions of calculations, generates a 3D surface by reverse engineering the distorted pattern back to the flat one.

The pattern is projected at varying scales to aid in the process.  The part to be scanned is sprayed with a white powder to enhance the contrast and increase accuracy.  The DAVID software interface helps align multiple scans, delete duplicates, stitch it all together and do generally anything you need to get a watertight mesh.
A couple of hours of scanning and then a couple of more of processing resulted in some models with excellent fidelity to the originals.


The scan results were as good with the rest of the parts:



I can now import the mesh files into Creo and use the vertices as references for axes, planes, and datum curve features for the rest of the assembly to mate to.

The rest of the assembly then mates to it and the engine starts to take shape.

Now the cylinder head and piston can be located in the chassis in the start of the process of achieving the desired center of gravity positioning.  Placement of the shaft centers and ancillary components is in process and once finalized, the skin of the crankcases starts to be generated.  The next couple of weeks will be a combination of CAD positioning, napkin and computer calculations, and some decent eyeballing, to get what I feel is the optimum layout.

Two missing parts, the cam chain guides, will be mechanically scanned using a Romer digitizing arm and then redrawn natively in CAD in the next episode.

Wednesday, January 8, 2020

Measuring the Crankcase Shaft Locations

Seeing how few of the original crankcase features will be carried over to the new cases a full 3D scan of them is not necessary.
It is surprising how little information is needed.  The dimensions of primary importance are:
  • crank to transmission input shaft distance
  • transmission shaft spacing
  • crank to oil pump intermediate gear distance
  • oil pump intermediate gear to oil pump shaft distance
  • crank to starter intermediate gear spacing
  • starter intermediate gear  to starter motor spacing
  • head stud bolt and pin spacing
The easiest way to measure these dimensions is directly.  With shafts in each bore/bearing, I mic'ed the OD of each then carefully measured the outside tangent distance.  Subtracting half of each shaft diameter results in an accurate center distance measurement.

I'll start with the primary drive side which has the primary and oil pump shaft centers.
ODs measured.



Measuring of the various centers.

Now on to the generator side that has the starter drive shafts.  Yes, a starter motor!  No more lugging around a car battery and external starter to get the beast started, just press the magic button.  Oh, I can't wait!!!!!!!
The starter motor was not long enough to get a good measurement so I turned up a close fitting plug and used that instead.

Of secondary importance is the shifter drum and linkage axis locations.  These are of secondary importance because if needed they can be replaced with custom components.  I would prefer to use the OEM parts but if they force a more important component to move or some chassis parameter to change, then I would rather make new ones that are exactly what is needed instead of compromising.

This is not all the information that I need to design the cases, but it is all the information I need to start to design the cases!

Tomorrow I will use a Romer scanning arm to generate the profiles and mounting hole locations of the two cam chain guides and cylinder head gasket.  Stay tuned!

Saturday, December 28, 2019

Mystery Solved

The purpose of this oil hole and seal really baffled me and was a problem since I needed to know what it really did in order to know if it was needed in my engine too.

Going to the world's largest image library, the internets, I was able to solve the mystery.  There is a nicely documented teardown of an earlier year Panigale engine here.

This image in particular (text/arrows are my addition) was what made everything clear:
Seeing this, I dug into a few different year Panigale microfiches at the AMS Ducati Dallas website.  There was a forced oil feed for the transmission output shaft on all the 1199 models up to the MY2014 but it was eliminated in MY2015 and later when they went to the 1299.  My 2016 1299 crankcases are not tapped for the oil tube mounting holes so I will not worry about trying to get pressurized oil there.

Friday, December 27, 2019

Dissecting the Panigale Engine

While taking the engine apart it is nice to look around the insides and see what clever details the Ducati engineers have figured out.  Of the two major changes in the engine design that were implemented in this new engine, one is nearly invisible and one is highly visible:  two stage oil system and chain/gear drive camshaft actuation.  I will review the oil system in this post.

The oiling system underwent a major redesign for this engine.  I would describe it as a hybrid dry/wet sump system.  The crankshaft cavity is well sealed similar to a two stroke crank area.  It is so well sealed that it is difficult to turn the crank by hand, even with both cylinder heads off!  You can hear the blowby similar to a compression stroke on a fully assembled engine.  This is not a problem during actual operation because you can see the new crankshaft scavenge stage is much larger than the pressure stage so during operation there would be a low vacuum in the crank mains area.


The oil pump works as shown in the attached image, the output of the scavenge serving to oil the trans before draining to the sump.  It is a clever design that makes the most of the pumping action of the scavenge stage and gives the return oil plenty of time to deaerate.


The sump then has a direct line to the intake of the pressure stage, then out to the fine filter, then into the oil galley to feed the rest of the engine.  Camshaft oiling is similar to the previous designs with the addition of line running to a hydraulic cam chain tensioner for each head.

One feature I am unsure of is on one end of the transmission output shaft.  It is a small roller bearing and there is a 6mm hole drilled in the crankcases that nothing goes into and is obscured by the clutch primary drive gear.


What I am unsure of is that that end of the transmission shaft has an oil seal installed.  There does not seem to be anything that goes into the seal so I am baffled as to it's presence.  Anybody have ideas?  There is no access to any other parts of the oil system through this bearing pocket or the rest of the trans shaft.

A Glance at the Past

After letting the MC Chassis Design internet mailing list know about the new projects, Robert Horn, of FF/FFE fame, sent me a link to a RoadracingWorld piece about the V4 project in 2011.

RoadRacingWorld V4 Article


I nearly forgot about this article but it nicely covers all the details about the inception of the V4 from the single.  The title leaves a little to be desired but it gave the project some good coverage.  Maybe there will be an updated article when this bike is finished.


Monday, December 23, 2019

Engine Teardown, Part 1


After stripping the rest of the bike from the engine it was time to get inside the cases.  I need to quickly determine which components will be reused and which will be discarded and new designs needed.  Once the side covers came off, I saw some interesting design features, primarily targeting noise reduction.  There were a few, a assume to meet the stringent EURO4 sound emissions regulations.  The details were:
  • The clutch cover had a sound dampening assembly in the cap that was about 3/4" thick, a pretty significant amount.
  • The cam chain guides were retained with bolts using o-rings to prevent rattle.
  • The primary drive gear had a spring loaded floating gear to eliminate gear rattle at low speeds
  • The clutch had a thin section belleville spring on the clutch hub to keep the friction pack from rattling when disengaged.
 

After all that effort to reduce mechanical noise, they used roller cam chains instead of 'silent' cam chain.  I wonder if the silent style chain was not strong enough.

Getting the side covers off, then removing the clutch and generator is one more layer of the onion off.  The OEM slipper clutch had only 3 springs but were assisted by a significant self-locking design on the slipper clutch hub.  Not only did the hub have a negative ramp that opened the clutch pack to create slippage when negative torque is applied, it also has a positive ramp which acts to tighten the pack pressure when slippage occurs when positive torque is applied.


Once all the covers and ancillary components were removed, what remained was what was really of interest:  shaft center locations.



By careful measuring and use of 3D scanning techniques I will establish the relationships between the various shaft centers.  This information will be transferred to CAD as a simple 2D sketch that can then be used as the basis of the new engine design

This may seem like a simple 2D drawing, but it contains most of the important engine dimensions has 'hidden' information which drives downstream relationships in the CAD model.


From the initial inspection it seems to make sense to use the following components/subsystems:
  • cam drive system
  • oil pump system
  • generator/starter assembly
  • cylinder head
  • transmission
  • shifter mechanism
  • piston/cylinder liner
That leaves the following components/subsystems in need of design:
  • crankcases
  • crankshaft
  • connecting rod
  • counterbalance shaft
  • water pump
  • oil passage system
The first stage will be to measure the transmission shafts, gears, and misc associated parts, since they are the largest component and the output sprocket position is an important location and needs to be fixed early in the design process.  The connecting rod will be a custom Carrillo H beam unit and will be as long as possible to minimize the engine's secondary vibrations.  The primary vibrations will be completely cancelled out through the use of a counterbalance shaft.  To achieve this, the crank balance factor will be 50%, the same as the counterbalance shaft.

The water pump will be an external on-demand electric pump supplied by Davies Craig.  I use this technology in the existing Rotacular with excellent results and temperature control with no need for duct tape on the radiator.  Seeing how much space is taken by the water pump (2 stage gear reduction) and the thermostat/distribution manifold, I am surprised that Ducati did not go a electric route.  They have the radiator, fan, shroud, and hose assembly design as a complete assembly that can be removed as a unit.  Integrating an electric pump would be a snap and simplify the overall routing.

The other decision to make is which head to use, the horizontal or vertical one.

The vertical head as two robust mounts used for the subframe that could be repurposed for a front engine mount but the decision will be driven by which side the cam drive and generator systems are cleanest to integrate into.

Once all of these shaft centers and their components are measured and put into the new arrangement, the crankcases are designed by creating an envelope around the parts, adding thickness to it, then adding ribs and gussets for strength.


So a little measuring and a lot of thinking are on my to-do list for the next couple of weeks.  I'll post updates as items become resolved.

Also, here is a nice gallery of disassembled Panigale engine pictures 


Chris

Sunday, December 22, 2019

Doubling down on 2020



After a difficult 2019 there was about a microsecond thought about scurrying away from the track with my tail between my legs.  However, common sense was locked in the basement and this year we're chucking in everything, including the kitchen sink.

First news is that a new single is in process, the Hypermono.  Second is that I’ll also be making a full mock-up of the V4 in the hope of drumming up interest to get it into running condition.  Third is there will be several racing events on the calendar, starting out using the Rotacular and with the Hypermono rolling out by June.  I’ll try to have a fast rider on it for the AHRMA Barber event in Oct that can challenge for the win in the open singles class, SoS1.

Having this all happen so quickly was a lot for me to digest.  A few seconds later plans were fully developed and in process.  A pretty wrecked but running and complete 2016 1299S to use as a donor appeared and the clock has started ticking.


I will be also IGing it with the hashtag #hypermono which will be mostly visual but most of the content will be posted here.  Lots of text does not go over well with the IG crowd.
 
The V4 will be a complete, non running version of the full bike, which has been amply documented on this blog.



The single will use the V4 FFE/idler rolling chassis, which initially was hijacked from the Ducati 1098-based single that never make it past CAD.  The 1098-based bike was supposed to be the successor to the existing Rotacular but the V4 took over, then fell prey to various factors beyond my control.  Sometimes shit happens.  Fortunately, motorcycle suspension has not changed in the past 10 years, so comparatively my design is as advanced today as it was 10 years ago.  Sigh.  For the swingarm I am thinking of doing a one piece aluminum sand casting using a 3D printed sand mold from Hoosier Pattern or Humtown and cast locally.  Then post-machining using the trunnion table on my VMC.  The largely complete chassis design also lends itself to fitting a big battery and motor so you never know want else might come out of the shop.



The history of this project is pretty long so here's a quick summary:

1999-2001- The Start Of It All: racing RS125 and TZ250 CCS/LRRS and USGPRU
2002-2006- Getting In Deeper: building and racing the first two version of the Rotacular
2007- How Deep Is This Hole?: designing the Ducati 1098 based successor to the Rotacular
2008-2009- Delusions Of Grandeur: 250GP class changed to Moto2.  The initial rules were for open engine specification, so I got an investor on board, jumped in and designed a 600cc V4 that used cut-in-half ZX-6R heads from an Attack Kawasaki Formula Xtreme bike. The engine would fit nicely into the nearly complete rolling chassis design for the 1098-based single cylinder engine.  About 6 months later, news came out that Moto2 would use a spec CBR600 engine, dashing any hopes of us getting into the GP paddock and forever relegating the middleweight Grand Prix class to irrelevance.
2010-2019- Licking Wounds:  Having dumped all my resources in to the V4 project, emerging into a recession-hit economy was not the best exit plan.  I recouped, ran down some new business, unrelated to motorcycles, yet kept tinkering in CAD in the hope it would all come good again.  And being happy that said investor takes a calm, long term view of things!
2020-It All Comes Good Again:  I repeat, it all comes good again.  And wow, that was 20 years of my life!

I now have everything needed to get the project started, so watch this space as it all comes together over the next 6 months.

Chris