Search found 1430 matches

by wturber
Jan 16 2019 3:45am
Forum: General Discussion
Topic: Telescope design; eliminating mirror-support diffraction
Replies: 7
Views: 216

Re: Telescope design; eliminating mirror-support diffraction

Forget magnets. The obstruction of the secondary mirror creates diffraction all by itself, no spider required. Yes, but the diffraction is evenly distributed and manifests itself mainly as lower image contrast. Look at the Chief design, it's an off axis telescope that is probably the easiest to imp...
by wturber
Jan 15 2019 9:48pm
Forum: E-Vehicles General Discussion
Topic: Wind and Solar vs Coal, Gasoline, Nuclear
Replies: 3170
Views: 107996

Re: Wind and Solar vs Coal, Gasoline, Nuclear

cricketo wrote:
Jan 15 2019 8:32pm
wturber wrote:
Jan 15 2019 8:13pm
But no, travelling on four wheels at 70 mph is inherently dangerous.
But horses can throw you out of the saddle, and cars won't do it! Cars are inherently safer! :mrgreen:
if you say so.

by wturber
Jan 15 2019 8:13pm
Forum: E-Vehicles General Discussion
Topic: Wind and Solar vs Coal, Gasoline, Nuclear
Replies: 3170
Views: 107996

Re: Wind and Solar vs Coal, Gasoline, Nuclear

"Inherently safe" generally refers to reactors that are safer than existing reactors based on passive cooling features. OK. What you are describing is propaganda then. There is nothing inherently safe about nuclear fission. This would be like me saying that Volvos are "inherently safe" to drive. Bu...
by wturber
Jan 15 2019 8:08pm
Forum: E-Vehicles General Discussion
Topic: Wind and Solar vs Coal, Gasoline, Nuclear
Replies: 3170
Views: 107996

Re: Wind and Solar vs Coal, Gasoline, Nuclear

I brought this up before. There is a group here that doesn't consider inherently dangerous handling of nuclear materials as an integral part of nuclear reactor operation, and then goes to compare nuclear safety with solar installers falling from roofs. Some logical acrobatics, not less. Personally ...
by wturber
Jan 15 2019 4:02pm
Forum: E-Vehicles General Discussion
Topic: Wind and Solar vs Coal, Gasoline, Nuclear
Replies: 3170
Views: 107996

Re: Wind and Solar vs Coal, Gasoline, Nuclear

You mean what occasionally fails to work now, with horrifying catastrophic and unrepairable consequences? No thanks. Nope. I am talking about inherently safe nuclear, not coal or existing nuclear. The AP1000 is an example; four are running now in China. That is one weird sentence. First of all, how...
by wturber
Jan 15 2019 3:24pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 131
Views: 1632

Re: APL's DIY axial-flux motor

Found this link on lamination bur's, or shorts, for reference. Another 'headache' PDF,..but very good information nun the less, and should probably be posted here. Explains all the effects of shorted lam's, with lots of FEM./graphics. https://orca-mwe.cf.ac.uk/50967/1/06571275.pdf Just skim through...
by wturber
Jan 15 2019 1:04pm
Forum: E-Bike Technical
Topic: Waterproof wire nuts vs soldering connections
Replies: 10
Views: 225

Re: Waterproof wire nuts vs soldering connections

The problem with soldering is that it can promote work hardening of the copper wire and you can break soldered connections with repeated vibration. That is why some people prefer crimping. The problem with crimping is that you need to make sure you know how to make a good crimped connection and you ...
by wturber
Jan 15 2019 2:53am
Forum: General Discussion
Topic: Telescope design; eliminating mirror-support diffraction
Replies: 7
Views: 216

Re: Telescope design; eliminating mirror-support diffraction

I'd be super concerned about having a secondary magnet drop down onto the main mirror if it was suspended by just magnetism. It would need some kind of locking mechanism to secure it until everything was set up and ready for use. Of course, I'm sure you are aware of the various catadioptric designs ...
by wturber
Jan 14 2019 4:45pm
Forum: General Discussion
Topic: Fewer Americans bike to work despite new trails, lanes and bicycle share programs
Replies: 14
Views: 307

Re: Fewer Americans bike to work despite new trails, lanes and bicycle share programs

Nationally, the percentage of people who say they use a bike to get to work fell by 3.2 percent from 2016 to 2017, to an average of 836,569 commuters, according to the bureau's latest American Community Survey, which regularly asks a group of Americans about their habits. That's down from a high of...
by wturber
Jan 14 2019 4:39pm
Forum: E-Bike General Discussion
Topic: Voltage regulator no juice
Replies: 10
Views: 172

Re: Voltage regulator no juice

I keep the grounds (negative leads) separate for each voltage I'm running. So the 48v, 36v, 12v and 5v circuits are all independent once the voltage conversion has happened. Yes, that appears to have been my problem! I disconnected the regulated ground from the ESC and now the lights don't even fli...
by wturber
Jan 14 2019 4:14pm
Forum: E-Bike General Discussion
Topic: changing gear ratios
Replies: 16
Views: 287

Re: changing gear ratios

It would probably be best for you to use a normal 53-39 tooth road double crank and a compatible front derailleur. It's easy enough to find these things secondhand if you want to economize. Yep. I find myself using either 53x13 or 53x15 for most of my steady-state nearly level riding. I only drop t...
by wturber
Jan 14 2019 3:47pm
Forum: E-Bike General Discussion
Topic: Dual suspensions Recumbent with steel frame. New build and futur updates
Replies: 5
Views: 114

Re: Dual suspensions Recumbent with steel frame. New build and futur updates

Consider getting an H4 LED lamp to replace your H4 Halogen. Not necessarily this particular one, but something like it. Then you can keep your converter and pull fewer amps from your battery. It might even be brighter. It's a win-win. https://www.amazon.com/Headlight-Motorcycle-Version-Bright-1400LM...
by wturber
Jan 14 2019 1:50am
Forum: E-Bike General Discussion
Topic: changing gear ratios
Replies: 16
Views: 287

Re: changing gear ratios

Think I'll just go for the freewheel swap first. Probably a bit easier. I want to remove the rear wheel to change to a fatter tyre anyway. Does anybody know what tool is required to remove the shimano freewheel from the chinese hub motors? You probably need this tool or the equivalent. The key feat...
by wturber
Jan 14 2019 1:42am
Forum: E-Bike General Discussion
Topic: Voltage regulator no juice
Replies: 10
Views: 172

Re: Voltage regulator no juice

But that ground problem.. I drive a LED (with its own regulator), a simple ohm meter (for monitoring a thermistor) and a atmega8 which is connected back to the ESC via the throttle signal and ground. I've always thought that stuff should share a common ground, even/especially when powered from diff...
by wturber
Jan 13 2019 5:12pm
Forum: E-Bike General Discussion
Topic: 40-50 mph 75 mile range
Replies: 50
Views: 1187

Re: 40-50 mph 75 mile range

Hey guys, I have built a bike that is close real close to this thread that we are on. It is a calibike kit. It will do over 50 mph and do well over 40 miles per charge . I have 250 miles so far and no problems at all I love it. THE bike Is 84 volts full charge and the controller will go max current...
by wturber
Jan 13 2019 4:53pm
Forum: E-Bike General Discussion
Topic: Voltage regulator no juice
Replies: 10
Views: 172

Re: Voltage regulator no juice

It's more or less exactly the same thing that happens when starting an older car - stereo and head lights die while the starter cranks. Maybe my battery isn't as strong as I thought. Simpler is better, wire it direct. Also, put a voltmeter on your batteries to see how much they are sagging under lo...
by wturber
Jan 13 2019 2:25pm
Forum: E-Bike General Discussion
Topic: Rim brake pads after ebike conversion
Replies: 9
Views: 297

Re: Rim brake pads after ebike conversion

How much does your actual bike (not coutning motor/battery) weigh? How much does his weigh? How much do you and the motor/battery weigh? I'll bet that the difference in actual bike weight is at best a couple of percent of the total bike/rider/motor/battery weight. If so, it would make a negligible ...
by wturber
Jan 13 2019 2:00pm
Forum: E-Bike General Discussion
Topic: How many tubes do you have?
Replies: 3
Views: 183

Re: How many tubes do you have?

I would use the patches and not scrap tube material. I think the patches provide a greater number of the right compound that will make a permanent bond with the inner tube. And you really need that permanent bond to form. You really aren't gluing the patch to the tube so much as you are causing the ...
by wturber
Jan 13 2019 1:35pm
Forum: E-Bike General Discussion
Topic: Voltage regulator no juice
Replies: 10
Views: 172

Re: Voltage regulator no juice

Hm yeah that sounds reasonable. There was no difference in acceleration, it just choked out the low power stuff I had connected. Once going, and keeping the power low enough it worked. I'll try to dig out some other 12v step down thing, never used the module for this application before so it's a li...
by wturber
Jan 10 2019 5:38pm
Forum: E-Bike General Discussion
Topic: 40-50 mph 75 mile range
Replies: 50
Views: 1187

Re: 40-50 mph 75 mile range

So fix the Delmar first, or sell it and buy a $200 bike from Craigslist. That will get you to work. Then save up to build an ebike. There are lots of options out there. But it's not going to give you what you think it can. Right. The situation was apparently precipitated by not paying for insurance...
by wturber
Jan 10 2019 3:31pm
Forum: E-Bike General Discussion
Topic: 40-50 mph 75 mile range
Replies: 50
Views: 1187

Re: 40-50 mph 75 mile range

Thanks for all the input guys. I am kinda gonna go different route, I originally wanted full electric because of the noise level compared to a four stroke bike and because I thought you had to have a license for any gas bike no matter what cc it is . Turns out I read the laws wrong so maybe down th...
by wturber
Jan 09 2019 1:34pm
Forum: E-Bike General Discussion
Topic: Arizona Legislature new e-bike/trails for 2019 Jan 1
Replies: 7
Views: 206

Re: Arizona Legislature new e-bike/trails for 2019 Jan 1

Seems to apply to new bikes as far as labels, IMO it's reasonable as the classes and where they can be ridden. A class 3 bike on a trail with non powered bikes and such? Hell no! Flash backs of the lycra mob on their 29'ers passing me w/o bell or voice announcement on the trails around Pittsburgh. ...
by wturber
Jan 08 2019 5:15pm
Forum: E-Bike General Discussion
Topic: Lines erased E-Bike / E-Scooter / E Motorcycle
Replies: 247
Views: 6548

Re: Lines erased E-Bike / E-Scooter / E Motorcycle

I dunno. I think traffic citations do modify behavior. I shudder to think what drivers would be doing if we had no traffic laws, no registration rules or vehicle safety regulations, no insurance requirements, and so forth. So I do think that regulations tend to make drivers better. Not perfect by a...
by wturber
Jan 08 2019 2:40am
Forum: E-Bike General Discussion
Topic: Lines erased E-Bike / E-Scooter / E Motorcycle
Replies: 247
Views: 6548

Re: Lines erased E-Bike / E-Scooter / E Motorcycle

Good regulation is a part of reducing ALL the risks to everyone You are a candid dreamer. :D There are no regulations that can make idiots and distracted drivers any better. I dunno. I think traffic citations do modify behavior. I shudder to think what drivers would be doing if we had no traffic la...
by wturber
Jan 07 2019 11:41am
Forum: E-Bike General Discussion
Topic: Video of ebike collision - be safe out there!
Replies: 23
Views: 644

Re: Video of ebike collision - be safe out there!

A good headlight is a very good idea, but a flashing headlight is very unwise. I'd be interested in seeing the study/data on this. And based just on the information you gave, I don't see how the "very unwise" claim would generally be true. In fact, in my area, considering the low density of pedestr...