Author Topic: Lauson LA build  (Read 17938 times)

Offline Admiral_dk

  • Full Member
  • ****
  • Posts: 1365
  • SÝften - Denmark
Re: Lauson LA build
« Reply #15 on: January 31, 2018, 12:03:25 PM »
Like most advanced tools - 3D software has a steep learning curve - but as you're discovering, it has a great potential for helping you avoiding big and small errors, when designing something new.

I'm still only using a small part of the options in my software tools, after a few years of using them.

Offline Craig DeShong

  • Full Member
  • ****
  • Posts: 471
  • Raleigh,NC. USA
    • Lauson small engines
Re: Lauson LA build
« Reply #16 on: January 31, 2018, 04:32:14 PM »
Yes Admiral, Iím completely with you.  Iíve had my share of confusion with this software, where I think it ought to do something one way and it does it another; but the BIG advantage Iím seeing at this venture is the way I can ďassembleĒ the engine and rotate the internal parts, checking for interference.  This is something I havenít been able do in the past and itís gotten me into a few scrapes that, fortunately, Iíve been able to circumvent

Here Iíve colored the parts and added some transparency (since I just looked into that and things WERE starting to get a bit confusing with everything the same color).  In the 3-D you can rotate the crankshaft and observe all the movement inside the crankcase, pretty cool.  Since my gears arenít really ďgearsĒ the camshaft isnít rotating with the crankshaft but I can rotate it separately if I choose.

With this set of drawings I have the cast iron sleeve installed (the block will be aluminum) with the crankshaft, the connecting rod journal bearing, the piston, the wrist pin, and the connecting rod; a few thrust washers also.
I still have a lot of design work to do; the governor, base, carburetor, and many other parts; Iím really looking toward designing the kick start: ought to be pretty interesting- still the design seems to be coming along nicely.  Thanks to all of you who are following this design. 

Iím sure Iíll be building this engine at this point- probably start this summer.
Craig

Offline Roger B

  • Global Moderator
  • Full Member
  • *****
  • Posts: 3952
  • Switzerland
Re: Lauson LA build
« Reply #17 on: January 31, 2018, 07:29:55 PM »
An interesting build  :ThumbsUp:  :ThumbsUp:  :wine1: I have yet to move to 3D modelling as well as CNC  :headscratch:  :old: I'm sure that Chuck (Fellows) is watching this in the background.
Best regards

Roger

Offline Craig DeShong

  • Full Member
  • ****
  • Posts: 471
  • Raleigh,NC. USA
    • Lauson small engines
Re: Lauson LA build
« Reply #18 on: February 01, 2018, 08:09:59 PM »
Thanks for the responses, nice to know some people is reading this tirade  ::)

Today was spent designing the governor cap and flyweight governor assembly.  The folks at Lauson, back in the early 1930ís, must have had time on their hands to design and then fabricate a pattern for this complicated  governor cap casting.  Iíve supplied a picture of it so you can see that to which Iím referring. 
   
Since Iím machining the parts to this engine, this was another situation where I needed to make compromises between what the part actually looks like and what Iím capable of producing.  Since the cap is hidden partially under a sheet metal cover, Iím not terribly worried about scale appearance; still Iíd like it to at least vaguely resemble its counterpart.

The cover Iíve designed is difficult to see in the CAD views I provide, I was more interested in seeing how the flyweights and actuator lever all fit together.  It took some adjusting and re-fitting but everything seems work-able at this point and it's easier to make corrections on the computer than re-make parts.
« Last Edit: February 02, 2018, 02:06:53 AM by Craig DeShong »
Craig

Offline Craig DeShong

  • Full Member
  • ****
  • Posts: 471
  • Raleigh,NC. USA
    • Lauson small engines
Re: Lauson LA build
« Reply #19 on: February 09, 2018, 12:56:46 PM »
Work has continued on the design of this model. With this post Iíve included the base and oil pump as well as the kick start mechanism. 

I have a lot of work remaining:  the valves, valve seats, and springs; the muffler; intake manifold, carburetor, and gas tank and mounts.  Also remaining are the magneto, flywheel, blower housing and sheet metal that covers most of everything up. :???:

You might note from the drawings that the oil pump merely lifts the oil from the oil sump to a dipper trough where splash lubrication does the ďrealĒ lubrication of the engine block internals.  This was pretty standard with Lauson until they built their  ď3rd generation enginesĒ with forced lubrication; a technique that Tecumseh continued to use in their designs after they purchased the company.

The Kickstart mechanism is fairly interesting.  Depressing the kick petal causes an intermediary helical/spur gear combination to slide over on its stub shaft where the spur gear portion of this gear combination engages with another spur gear on the crankshaft to rotate the engine.  When the engine starts, this intermediary gear combination is pushed back across its stub shaft, thus disengaging it from the crankshaft gear.  An Idler gear on a spring holds this intermediary gear combination in place so it wonít engage with the crankshaft gear again until needed.

Iím noticing that the final assembly drawings are getting quite busy and Iím beginning to wonder the usefulness of them; it takes a while to assemble everything with the software.  As I stated previously, this is the first go-round with this 3-D software so Iím still learning.  Iím using ďCubify DesignĒ if youíre wondering. 

This design is well enough along that I could begin construction I suspect; but I have another model Iím trying to finish (If it ever gets warm enough to venture out to my unheated shop).  Iím looking at this project as starting sometime in the Spring.
Craig

Offline Art K

  • Full Member
  • ****
  • Posts: 1132
  • Madison, Wisconsin USA
Re: Lauson LA build
« Reply #20 on: February 09, 2018, 06:14:14 PM »
Craig,
I wanted to let you know that I'm following along. This is an interesting engine to build. I have a B&S from I think 1936-37 it is a model WMI with the deep sump and pressurized oil system.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Online Brian Rupnow

  • Full Member
  • *****
  • Posts: 5087
  • Barrie, Ontario Canada
Re: Lauson LA build
« Reply #21 on: February 09, 2018, 11:56:27 PM »
Craig--I'm following. 3D cad is quite wonderful, and can do the most amazing things--but the learning curve is very steep. I use Solidworks which I started with in 1999 or 2000 (can't remember for sure). Your build looks interesting--Don't worry too much about how many people are following but don't actually post anything. You will get a lot more people showing up and commenting when you start making parts in metal.---Brian

Offline Craig DeShong

  • Full Member
  • ****
  • Posts: 471
  • Raleigh,NC. USA
    • Lauson small engines
Re: Lauson LA build
« Reply #22 on: February 15, 2018, 01:12:29 AM »
I continue to make steady progress on the design of this model.  Iíve completed the design of the carburetor and intake manifold.  The carburetor was fairly easy since it is another Tillotson MS74 type carburetor.  I designed one very similar when I built the Lauson TLC model a few years ago.  All I really needed to do was to pull out the old drawings and make some changes, since this carburetor is, essentially, a mirror image of the one I built for the TLC. Of course, I wanted to update the drawings with this new software too.

Iíve included an exploded view and several assembled views of this float carburetor.  In this first exploded view, the intake manifold is positioned away from the viewer.  You get a good view of the needle seat, gland, cap, and main needle to the bottom right.  Both the throttle (sliding in from the left) and the choke (assembling from the top) are barrels rather than butterfly valves.  This has worked well for me with my previous models.  Iíve included all the parts in these views with the exception of the setscrews that terminate the carburetor passages and the fuel shutoff needle itself that sits above the float and pressure plate and slides into the orange valve seat.  The first picture is this exploded view.

The second picture is an assembled view of the carburetor, looking from the front flange that attaches to the intake manifold.  Youíre looking down the throat of the carburetor.

With the third picture I give you a view from the rear of the carburetor, showing the assembled choke barrel and attachment flange for an air cleaner.

I thought Iíd try a different approach on the intake manifold which too, is similar than the one I constructed for the TLC.  With this go-round, Iím thinking of machining the manifold ends in two parts and threading them together.  Donít know how well this will work or not but Iím hoping Iíll get closer to a realistic shape without all the filler work I did on the TLC. 

With the fourth and fifth pictures you see exploded views of the intake manifold, the extreme ends will be threaded and then affixed in place with Locktite once I get the angles right.

Lastly, is a view of the assembly so far.  My software creates animated PDFs that you can grab and spin around.  I was thinking it might be fun to provide one of these for yíall to play with.  I spent a little time trying to publish one of these but the PDF file is quite large, weighing in at a little over 4 Meg; too large for this model engine maker website to accept.  I was going to serve it from my own web server, but browsers deem these animated PDFs a security risk and to view one youíd have to override a bunch of security questions that, to be quite frank, Iíd be hesitant to do myself from an unknown source.  I ended up just giving you another static JPG image.

On another note, the time has come to start thinking about the magneto.  Iím fairly certain I could construct an operational one but if I canít find appropriate sized coils Iíd need to wind them myself.  I have a friend who wound one, but heís making noises that indicate I want to think long and hard before I commit to it.  I suspect I can go ahead and design an operational magneto, and if the coils donít workout I can just use the points and fall back to battery/coil ignition as Iíve used on my other Lauson models.
« Last Edit: February 15, 2018, 12:43:55 PM by Craig DeShong »
Craig

Offline Craig DeShong

  • Full Member
  • ****
  • Posts: 471
  • Raleigh,NC. USA
    • Lauson small engines
Re: Lauson LA build
« Reply #23 on: February 16, 2018, 04:21:25 PM »
I finished the design of the magneto today.  This is a replica of a Wico FG Flywheel magneto.  These magnetos bear some explanation so here goes:

The frame of the magneto is what loosely can be seen as two opposing letter ďEĒs with the center post of the ďEĒ passing through coils (green in the diagram) and the bottom and top posts touching bar magnets.  These bar magnets (the black objects you see nearly hiding at the center top and center bottom) will be rare earth magnets in the model.  They setup a permanent magnet field, causing the left ďEĒ to be magnetized as ďnorthĒ while the right ďEĒ is magnetized as ďsouthĒ.

A center rotor, driven by a pin on the flywheel, spins in the center and the shape of the rotor causes the magnetic field passing through the coils to build and collapse as the rotor spins.  The two coils have their primary windings connected in series with the points.  The secondary high voltage windings are also connected in series.  A set of points will open, just as the magnetic field collapses, thus causing a high voltage to be produced in the secondary winding of the coils.  A condenser is connected across the points, not shown in the diagram.

I donít see why this replica shouldnít function as the original, assuming I can find (or wind) suitable coils.  The coils need to be no larger than 1 ľ inch diameter and 5/8th inch tall.  They need to have (preferably a square) open center of approximately 1/2 inch. They need to have both their primary and secondary winding isolated from ground; so if anyone ďout hereĒ can give me a lead on where to procure two ignition coils such as this, Iíd appreciate it.
« Last Edit: February 16, 2018, 04:27:17 PM by Craig DeShong »
Craig

Offline Art K

  • Full Member
  • ****
  • Posts: 1132
  • Madison, Wisconsin USA
Re: Lauson LA build
« Reply #24 on: February 16, 2018, 05:13:26 PM »
Craig,
Before I even started building my Upshur vertical single I bought the spark plug, coil and piston rings. I never used the coil since I used S/S CDI ignition with automotive points. Unfortunately I can't find the coil to give a dimension and an online search doesn't turn them up. As an after thought you might contact Roy at S/S he uses small coils in his CDI ignitions and that might work in your application. http://www.cncengines.com/
Art
« Last Edit: February 16, 2018, 11:02:40 PM by Art K »
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline Admiral_dk

  • Full Member
  • ****
  • Posts: 1365
  • SÝften - Denmark
Re: Lauson LA build
« Reply #25 on: February 16, 2018, 08:58:00 PM »
A very interesting ignition system - never seen anything like it.

If you decide to wind the coils yourself, you should be aware of insulation issues or more correctly how to wind them so they will continue to work. I'm not sure if it's important witch coil to wind first in this kind of system - but I do know that you will have to use a few layers of high voltage insulating tape between the primary and the secondary and a layer for every 100 volts of secondary ...!!
If you don't do this you will get arcing inside the coils and a burned ignition system  :zap:
Oh - and I forgot that you should use a few layers of tape on the coil-former before adding wire - unless the coil-former is made from a good electrical insulator material.

Offline Roger B

  • Global Moderator
  • Full Member
  • *****
  • Posts: 3952
  • Switzerland
Re: Lauson LA build
« Reply #26 on: February 17, 2018, 07:47:26 AM »
I believe that there is a book, possibly by Edgar Westbury, on making magnetos.
Best regards

Roger

Offline Roger B

  • Global Moderator
  • Full Member
  • *****
  • Posts: 3952
  • Switzerland
Best regards

Roger

Offline Craig DeShong

  • Full Member
  • ****
  • Posts: 471
  • Raleigh,NC. USA
    • Lauson small engines
Re: Lauson LA build
« Reply #28 on: February 20, 2018, 08:28:34 PM »
Thanks for the tips on winding coils.  Iím going to follow up on these and see where they lead me.  Iíve always been an advocate of the ďdivide-and-conquerĒ philosophy, so I will probably choose to start with battery and coil ignition, and once I get the engine running, look into making a magneto.

I finished the design of the engine today.  I give you four views, and immediately apologize for the lack of clarity.  The 3-D views are so busy at this point that even I have difficult making out what is what so I can only imagine how difficult it is for you who arenít as imminently familiar with the design as I am.

In this laller design period Iíve found these 3-D views to be extraordinarily useful for tasks such as fitting the sheet metal cover, where the CAD tool allowed me to make measurements across several different assemblies and design a cover that would fit.  I would normally do this on the model itself.

We might think all the CAD work is complete at this point, but actually it now it moves on to a new phase- that being getting actual drawings from the tool with which the parts can be fabricated.  I have very limited experience with using this part of the tool, this being my first design with this software.  Itís going to be yet another learning experience.  Fortunately there are plenty of chilly days remaining in this winter where Iíll have time to explore this portion of the software. 

Iím getting really enthused about beginning the actual build so Iím hoping I can have some drawings ready when the weather breaks.       
Craig

Offline Craig DeShong

  • Full Member
  • ****
  • Posts: 471
  • Raleigh,NC. USA
    • Lauson small engines
Re: Lauson LA build
« Reply #29 on: February 22, 2018, 09:53:14 PM »
Since my last post Iíve been getting my CAD program to produce some working drawings.  Actually it proved to be pretty easy; the software seems to be imminently flexible.  I can produce an ďeasyĒ drawing from the 3-D part in less than a minute.  I was thinking of continuing with this today, but the day dawned warm and clear here in North Carolina; with the temperature attaining 70 degrees by midday.  This was too nice of a day to spend cooped up inside and another session with the computer.   

As the farmers say, ďmake hay while the sun shinesĒ so I got to thinking that I just might have a block of aluminum in inventory large enough to use for the block and after looking I found just the piece; a remnant from a larger piece I obtained from a scrap yard some time ago.  Along with the aluminum I scored some cast iron I can use for the cylinder sleeve and valve guides (I guess it pays to order more than you immediately need after all)

Armed with this material I STARTED THE BUILD  :cartwheel: by grossly sizing the block.
 


There are few of these faces that will remain with the completed model, but as you know, I need to get this thing "square" and establish points of reference from which I can take measurements down the road.

I believe I remember reading someone in another thread stating that the problem with building from bar stock is that a lot of effort is spent on cosmetic issues, not functional, mechanical ones.  As I made mountains of swarf today in sizing this block of aluminum Iíll agree with that statement.
« Last Edit: March 06, 2019, 02:01:03 PM by Craig DeShong »
Craig