Search found 12 matches

by PwEngineer
Wed Feb 23, 2005 9:31 am
Forum: Raingutter Regatta
Topic: We had the Raingutter Regatta tonight
Replies: 9
Views: 27142

Re: We had the Raingutter Regatta tonight

You are right, the BSA kit is very unstable and if built the way the derby book shows, many of your pilots will be exhausted after blowing the boats. :mrgreen: Our boat designs are very stable and the best can be blown with 3 puffs, 10 feet in less than 5 seconds (blower must practice) by a youngste...
by PwEngineer
Thu Jan 29, 2004 12:12 pm
Forum: Car & Semi-Truck Construction
Topic: SPACE GAP BETWEEN WHEEL HUB AND CAR BODY
Replies: 3
Views: 6389

Re: SPACE GAP BETWEEN WHEEL HUB AND CAR BODY

Well, I think Stan has good intuition and experience with these issues. But we do have some data and analysis we can look at. Things are rarely as simple as we'd like them to be. As you will see, Stan is at least partly right! In our DOE Screening Time Trial gaps of 1/128 and 1/16 inch were used alo...
by PwEngineer
Fri Oct 17, 2003 9:19 pm
Forum: Car & Semi-Truck Construction
Topic: Inertial and Vibration Losses?
Replies: 37
Views: 48994

Re: Inertial and Vibration Losses?

Hi all, thought about starting a new topic for this, but here goes anyway - :?: Does anyone know where the rule banning springs came from? Can someone get ahold of Don Murphy to see if he started it? What was the intended purpose? Where did they think the springs would be used and for what purpose? ...
by PwEngineer
Tue Oct 14, 2003 2:13 pm
Forum: Car & Semi-Truck Construction
Topic: Inertial and Vibration Losses?
Replies: 37
Views: 48994

Re: Inertial and Vibration Losses?

Another Mike?? Glad to meet you. I can't chat long, but I'd like to know more about "Sorbothane". I'd do a web search, but I have "real" work to do! I can't say much right now, but the suspension angle has possibilities for four wheelers. Give me a few days (weeks?) and I'll be h...
by PwEngineer
Mon Sep 22, 2003 12:00 pm
Forum: Raingutter Regatta
Topic: Raingutter Regatta Track Designs
Replies: 10
Views: 50037

Re: Raingutter Regatta Track Designs

Da Graphite Kid, I feel really bad that you can't find "lipless" raingutters at your hardware store :cry:. They work so well for us. We just lay them flat on the tables (takes at least 2) right next to the edge - one on either side. The little rise at each end from the end cap has not made...
by PwEngineer
Fri Sep 12, 2003 9:10 am
Forum: Raingutter Regatta
Topic: Not Just Boat Design, It Tests the Pilot Too!
Replies: 6
Views: 16111

Re: Not Just Boat Design, It Tests the Pilot Too!

Da Graphite Kid, I've posted all our 2 or 3 second boat tips at http://www.lastufka.net/lab/boats/ for free and wrote a booklet for Scouts and others who want more specific application of those principles to BSA-like kits. There's no reason for any pilot to get winded! If you have QuickTime on your ...
by PwEngineer
Thu Sep 11, 2003 4:01 pm
Forum: Raingutter Regatta
Topic: Not Just Boat Design, It Tests the Pilot Too!
Replies: 6
Views: 16111

Not Just Boat Design, It Tests the Pilot Too!

As much as I like Pinewood Racing, I have to admit my favorite club race is Raingutter Regatta! In PW, it's all in the car. In RR, you have to train too. It's a contest of your piloting skill and your design/construction skill. When we increased the speed of the boats in our club races from 20 secon...
by PwEngineer
Fri Aug 29, 2003 11:29 pm
Forum: Car & Semi-Truck Construction
Topic: Speed impact of various types of lubrication
Replies: 34
Views: 37709

Re: Speed impact of various types of lubrication

This is a difficult topic as there is so much variation in how people apply lubes, the brands, the materials the wheels are made of, the response of the lube to humidity, temperature, etc.. We have also run lube trials and generally concur with Randy's conclusions up to the caveats above - although ...
by PwEngineer
Thu Aug 28, 2003 12:14 pm
Forum: Car & Semi-Truck Construction
Topic: Axel Diameter: Is smaller really better?
Replies: 29
Views: 38879

Re: Axel Diameter: Is smaller really better?

It actually happens all the time. As I said, "From the point of view of the contact point, the wheel is spinning about the contact point for a very short time." The most notible time it happens in PW racing is when you spin the wheels sometimes they vibrate or buzz. That indicates the whee...
by PwEngineer
Tue Aug 26, 2003 11:37 am
Forum: Car & Semi-Truck Construction
Topic: Axel Diameter: Is smaller really better?
Replies: 29
Views: 38879

Re: Axel Diameter: Is smaller really better?

For Tread Friction see http://www.worldforchrist.org/races/cars/why/fdrag.htm . "Stiction" is short for sticky friction - I don't believe it's a "first-class" tribology (science of friction) term. This kind is properly called "rolling friction" as Stan pointed out a few...
by PwEngineer
Mon Aug 25, 2003 2:13 pm
Forum: Car & Semi-Truck Construction
Topic: Axel Diameter: Is smaller really better?
Replies: 29
Views: 38879

Re: Axel Diameter: Is smaller really better?

Hi all, The Sensitivity of Wheel Friction to Axle and Tread Friction Coefficients article at http://www.worldforchrist.org/races/cars/why/africt.htm#critical includes the wheel bore radius, r and the wheel tread radius, R. Wheel Drag (Dw)= Axle Friction + Tread Friction = nFr/R + 2u(F/2+w) n is the ...
by PwEngineer
Mon Aug 25, 2003 11:50 am
Forum: Car & Semi-Truck Construction
Topic: Inertial and Vibration Losses?
Replies: 37
Views: 48994

Re: Inertial and Vibration Losses?

Hi all, I finally got time to read some topics! There's some good stuff rolling around here. Keep up the good work Darin M. :wink: for explaning in a simple way. What someone really needs to do is make a few measurements on some pine of various thicknesses to get a "bulk modulus" (I need t...