Landracing Forum Home
July 17, 2018, 10:35:13 AM *
Welcome, Guest. Please login or register.
Did you miss your activation email?

Login with username, password and session length
News:
BACK TO LANDRACING.COM HOMEPAGE
 
   Home   Help Search Calendar Login Register  


(Note: Donations are not tax deductible)







Live Audio Streaming and Archives of Past Events
Next Live Event: TBD
Pages: 1 ... 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 [49] 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 ... 206   Go Down
  Print  
Author Topic: Team Go Dog, Go! Modified Partial Streamliners  (Read 641516 times)
0 Members and 8 Guests are viewing this topic.
wobblywalrus
Hero Member
*****
Offline Offline

Age: 64
Location: backwoods Oregon
Posts: 4653





Ignore
« Reply #720 on: March 15, 2012, 08:55:13 PM »

A call was made to the local plastics shop.  They are enthusiastic about using the PETG and I agreed to let them do it.  It has these advantages.  It can be draped formed and this process makes a smoother finish on the inside of the windshield than vacuum forming.  It is almost impossible for me to make a wooden mold smooth enough to give a finish that does not need to be sanded and polished if it is vacuum formed.  The PETG has little memory, unlike polycarbonate.  It will not tend to spring back to its flatter original form when it is being molded.  There is much less problems with internal bubbles due to inadequate preheating.  Preheating is not needed.  Another advantage is cost.  The cell-cast acrylic in aircraft grade is expensive, and polycarbonate and PETG are relatively cheap.  This is a material they do not normally use and I need to buy an entire sheet.

The PETG is shatterproof and it will meet AMA and FIM requirements.  The SCTA and DLRA mention polycarbonate in their rules.  I would need special permission from the them to use the shield.

It is hard to find the low spots when the finishing sanding is done.  The mold is painted with engine primer and then it is sanded.  This shows me where the low spots are.


* Fairing Rebuild 132.JPG (169.21 KB, 800x533 - viewed 194 times.)
Logged
wobblywalrus
Hero Member
*****
Offline Offline

Age: 64
Location: backwoods Oregon
Posts: 4653





Ignore
« Reply #721 on: March 18, 2012, 10:12:42 PM »

Tapping a big hole can be tricky.  It is difficult to center the tap so it goes in straight and square.  My method is to use the drill press to keep everything lined up.  First, I check the table to make sure it is perpendicular to the drill press spindle axis.  Then I bolt the part to the table.  Now a washer is put in the hole.  The hole in the washer is in the center of the hole to be tapped.  Next, I put a drill in the chuck upside down.  I lower the shank down and move the part around until the shank is centered in the washer hole.  Then the table is clamped tight.  Exhaust Mods 2 shows this.

This tap has a dimple in the center of the top.  I use a roller from a Matchless rod bearing to center the tap.  A Harly or BSA roller will not do.  It needs to be a Matchless one.  Or AJS.  Little taps do not have a dimple and I use a sleeve over the top of them.  Exhaust Mods 3 shows a roller and a sleeve.  Exhaust Mods 4 shows the roller in place.


* Exhaust Tuning 2.JPG (139.08 KB, 612x480 - viewed 116 times.)

* Exhaust Tuning 3.JPG (135.62 KB, 640x477 - viewed 100 times.)

* Exhaust Tuning 4.JPG (104.06 KB, 640x451 - viewed 111 times.)
Logged
wobblywalrus
Hero Member
*****
Offline Offline

Age: 64
Location: backwoods Oregon
Posts: 4653





Ignore
« Reply #722 on: March 18, 2012, 10:55:24 PM »

Now everything is lined up and I start to turn the tap.  One hand is on the adjustable wrench and the other is on the drill press spindle handle.  I am moving the spindle down while I rotate the tap.  Exhaust Mods 5 shows this.  I watch the upper thread in the part real close and I stop turning when this thread is just at full depth.  A common mistake is to keep going and to force a taper tap to cut deeper.  This is hard on the tap and it can break.

Tap drill sizes for pipe taps are hard to find.  I used the internet to find them and they were on www.newmantools.com/tapdrill.htm.  The tap I am using has a 1-5/32 inch tap drill size for normal embedment of 1/3 to 1/2.  In other words, the pipe end will screw in 1/3 to 1/2 of its threaded length.  I want 100 percent embedment so I use a 1-3/16 drill as a first attempt.  The tap is turned until I cut the upper thread in the part to full depth and I remove the tap.  Then I screw in the pipe end.  It goes in 1/2 of the way.  The pipe is unscrewed and I enlarge the hole with a drill one size bigger.  Then I tap till the upper thread is cut to depth and I try again.  It took another try and the threads finally got big enough and the pipe end went in to full depth.  Exhaust Mods 6 shows this.

The point I am trying to show is, if you want deeper embedment than the typical 1/3 of the male threads, use larger tap drills to make wider female threads.  Do not use a standard tap drill and all sorts of brute force to do the job. 

   


* Exhaust Tuning 5.JPG (118.91 KB, 535x480 - viewed 117 times.)

* Exhaust Tuning 6.JPG (152.13 KB, 640x417 - viewed 129 times.)
Logged
wobblywalrus
Hero Member
*****
Offline Offline

Age: 64
Location: backwoods Oregon
Posts: 4653





Ignore
« Reply #723 on: March 20, 2012, 12:34:42 AM »

The Plan A is to try drape molding with PETG at a local shop.  Plan B, if this does not work, is to have the windshield vacuum formed from polycarbonate in Portland.  There is a limit on how smooth I can make a bare wood mold.  Some special high temperature sealer for molds is on order.  It will take a few weeks to get it.  This will allow me to make a very smooth surface which is helpful for drape molding and essential for vacuum molding.  I do not want to use anything besides a high temp sealer.  A coating that melts and contaminates the plastic will ruin everything.

The spray paint method in a prior post showed how I got rid of the low spots.  It does not tell me where the flat spots and bumps are.  To do this, I roll a straight edge over the mold and this shows me where they are.  I circle the high spots and sand them down.  The lines on the mold show where this has been done.

My middle boy is out of combat and preparing to come home.   


* Fairing Rebuild 133.JPG (169.88 KB, 800x533 - viewed 199 times.)

* Fairing Rebuild 134.JPG (172.75 KB, 800x533 - viewed 167 times.)
Logged
wobblywalrus
Hero Member
*****
Offline Offline

Age: 64
Location: backwoods Oregon
Posts: 4653





Ignore
« Reply #724 on: March 20, 2012, 11:56:27 PM »

Thursday is dyno day.  The bike is prepared and the dyno plan is ready.  These are a few things I do.

1)  The jets are original equipment Keihin jets I have checked with a needle to make sure they are correct.  The use of shop jets can be problematic.  Their quality is not known.

2)  The mechanic always wants to know what I have changed.  He also wants to know what is the same.

3)  The correction factor I use is always SAE.  The factor influences the calculated results and it needs to be consistent from year to year.  This makes it easier to compare results from different sessions to each other.

4)  The old runs are on file and it is nice to tell him the best run from the previous year.

5)  "Do not assume, test" is what the exhaust pipe expert told me.  I have three exhaust systems, Arrow pipes with and without baffles and standard pipes with British Custom mufflers.  All will be tested.

While writing this I noticed a mistake or two in my dyno plan.  They will be fixed and It will be posted.       
Logged
wobblywalrus
Hero Member
*****
Offline Offline

Age: 64
Location: backwoods Oregon
Posts: 4653





Ignore
« Reply #725 on: March 21, 2012, 12:34:18 AM »

Champ or chump tuner?  Engine wizard or motor lizard?  Thursday afternoon I will know.  Maybe you will too.  Depends on the results.  Dyno plan is attached. 


* 2012 Dyno Session 1.jpg (123.32 KB, 768x999 - viewed 121 times.)
Logged
Old Scrambler
Sr. Member
****
Offline Offline

Age: 71
Location: Plymouth, WI
Posts: 649


Going Fast - Slowly




Ignore
« Reply #726 on: March 21, 2012, 01:49:14 PM »

Wobbly...........check your plan for running without baffles before you actually remove them............I have not dynoed by instrument, the great white salt-flats seem to show consistent results.
Logged

2011 AMA Record - 250cc M-PG TRIUMPH Tiger Cub - 82.5 mph
2013 AMA Record - 250cc MPS-PG TRIUMPH Tiger Cub - 88.7 mph
2016 AMA Record - 750cc M-CG HONDA CB750 sohc - 130.7 mph
2016 AMA Record - 750cc MPS-CG HONDA CB750 sohc - 137.7 mph
Chasis Builder / Tuner: Dave Murre
grumm441
Hero Member
*****
Offline Offline

Location: Somwhere in Australia
Posts: 1433

HK 327




Ignore
« Reply #727 on: March 21, 2012, 07:38:59 PM »

Hey WW
Why don't you give it a run with the three yellow/white wires from the charging system disconnected and see if it makes any difference
G
Logged

Chief Motorcycle Steward Dry Lakes Racers Australia Inc
Wazavudu Bellytank  Spirit of Sunshine Bellytank
wobblywalrus
Hero Member
*****
Offline Offline

Age: 64
Location: backwoods Oregon
Posts: 4653





Ignore
« Reply #728 on: March 21, 2012, 08:31:52 PM »

Old Scrambler, the baffles are an experimental setup I made for the street.  They probably will cost me power and I just want to see how much the loss is.

Grumm, is it a horsepower difference I should be looking for?

I am not sure this dyno day will happen.  This is what was out there a half hour ago when I put the bike on the trailer.  It is an hour's drive to the shop early in the morning.


* 2012 Dyno Session 2.JPG (278.79 KB, 800x533 - viewed 115 times.)
Logged
wobblywalrus
Hero Member
*****
Offline Offline

Age: 64
Location: backwoods Oregon
Posts: 4653





Ignore
« Reply #729 on: March 22, 2012, 11:45:12 PM »

It was a pretty drive to Portland.  There was 4 to 6 inches of r fresh snow.  None of us are real experts here.  What is happening during these dyno pulls?  2012 Dyno Session 3 shows a red curve for pull 70.  This was early in the session.  Note the smoother shape near the horsepower peak.  The blue curve is for pull 86.  It was later.  See the dip near the peak.

2012 Dyno Session 4 shows some weirdness on pulls 81 and 102.  This was happening on intermittent pulls.  Two more curves will be shown in the next post.       


* 2012 Dyno Session 3.jpg (146.7 KB, 768x986 - viewed 102 times.)

* 2012 Dyno Session 4.jpg (150.33 KB, 768x990 - viewed 110 times.)
Logged
wobblywalrus
Hero Member
*****
Offline Offline

Age: 64
Location: backwoods Oregon
Posts: 4653





Ignore
« Reply #730 on: March 22, 2012, 11:50:09 PM »

Two really funky pulls, # 91 and # 95 on 2102 Dyno Session 5.  Note the strange mixture curves.  Several pulls are plotted together on 2012 Dyno Session 6.  Note how they follow a common pattern.

We thought we hear d the clutch slip on a few of these strange pulls.     


* 2012 Dyno Session 5.jpg (133.75 KB, 768x966 - viewed 100 times.)

* 2012 Dyno Session 6.jpg (143.88 KB, 768x1002 - viewed 94 times.)
Logged
MattGuzzetta
Full Member
***
Offline Offline

Age: 76
Location: San Diego, CA
Posts: 99





Ignore
« Reply #731 on: March 23, 2012, 01:04:38 AM »

We used to have our road racing bubbles made by a company in L.A. that made optically clear bubbles by heating the sheet in a "hanging sheet" oven that heated the material evenly and they they place the sheet over a "ring" mold which was an oval hole in the top of a large box that they would pull a vacuum in (not a high vacuum, just enough to pull the sheet down)and the material was "free  formed" evenly.  They are out of business, but the method is a great way to get optically clear bubbles without touching a mold.  Here is a link (a loooong link) to a factory manual of forming acrylic that may give you a better knowledge of what is going on.
  https://docs.google.com/viewer?a=v&q=cache:v4swlRMPdLoJ:www.atoglas.com/literature/pdf/135.pdf+hanging+sheet+oven&hl=en&gl=us&pid=bl&srcid=ADGEESgBpJ6xKMPGbQPxPGbJ5NllQm1d30poyiFXFGftcCwRleJ2r_21ujve-pyZsLbAUss0UL5aYJC1XC913A2gwDLJRvyLwrnFLeFIMIE8x4dXFtjcfLLXKiYamWq9HtFzkXqHQWKE&sig=AHIEtbQjxt7rvgSIUl-eC9DEsStoCSFLcA

Of course it is better to make the bubble, then design the fairing to fit, but the manual is worth looking through.  I have made windshields by both draping and vac forming and it was a big job sanding and polishing the vac formed parts to be able to see through them.....not very well, but they were on a sports racing car, so you mostly looked over the windscreen. Hope this helps a bit!   grin


The windshield on this econo bike was a free blown unit and the headlamp cover was a plaster mold covered with felt and sanded after molding.

Matt Guzzetta

Logged
Jon
Sr. Member
****
Offline Offline

Age: 51
Location: Brisbane, Australia
Posts: 852





Ignore
« Reply #732 on: March 23, 2012, 01:07:41 AM »

If the clutch was slipping there should be a temporay mismatch between wheel and engine rpms, did you get full data point files or just graphs?

The midrange dips, were they with standard ignition?
I've seen a few factory ignition curves that have advance dips that coincide with noise/emission testing rpm ranges.

Jon
Logged

Underhouse Engineering
Luck = Opportunity + Preparation^3
wobblywalrus
Hero Member
*****
Offline Offline

Age: 64
Location: backwoods Oregon
Posts: 4653





Ignore
« Reply #733 on: March 24, 2012, 11:28:10 AM »

Matt, the local plastic shop wants to try to drape mold the PETG over the form and I told them I would do it.  That will be Plan A.  Plan B will be to have it made with this hanging bubble method if the cost is reasonable.  Thanks for posting this.

Jon, your advice is absolutely correct.  The shop compared wheel to engine rpm on a problem pull.  The data showed that the clutch was slipping when the engine put out more than 70 horsepower.  Aftermarket plates and springs were recommended to me when I built the motor.  I was cheap and lazy.  I did not put in the plates and I replaced half of the standard springs with stiff ones.  The clutch will be beefed up in a few months when it gets warmer in the shop.

In a recent post I mentioned how I needle check my jets and use original equipment jets, only.  I gave the mechanic the jet box with the words "All of these jets are Keihin and they have been checked for size.  Use them."

There were a pair of jets marked "AB142" in that box.  I somehow did not find them and toss them out.  The holes in them are a size or two bigger than the orifices in Keihin #142's.  The mechanic put them in, they made the bike run overly rich, and they completely confused the jetting sequence.  It took a bunch of pulls and time to figure out the problem.  Those AB142's were some expensive jets when I paid the bill.  Dyno work is like racing.  A person has to check and double check to make sure everything is OK before the big day.     
Logged
Freud
Hero Member
*****
Offline Offline

Age: 86
Location: Everett, WA - USA
Posts: 5415




Ignore
« Reply #734 on: March 24, 2012, 12:25:24 PM »

Don't rely on jet numbers or needle size. The only way to know is to flow it.

Same sized holes don't always flow the same amount.

FREUD
Logged

Since '63
Pages: 1 ... 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 [49] 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 ... 206   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.21 | SMF © 2015, Simple Machines
Simple Audio Video Embedder
Valid XHTML 1.0! Valid CSS!


Google visited last this page June 16, 2018, 11:26:09 AM