Here's a great spring calculator
http://icrank.com/cgi-bin/pageman/pageout.cgi?path=/data/spring/spring.htm <http://icrank.com/cgi-bin/pageman/pageout.cgi?path=/data/spring/spring.htm&; t=2> &t=2 If you enter the spring parameters (wire diameter, length, etc.) it will tell you how much weight is required to cause a given spring deflection. Play around with it, you'll see what I mean. After you get a rough idea of the size of springs you'll need, you can search McMaster for something close to those to values. You can make compression springs yourself, but it's tricky. Torsion and extension springs are much easier. Of course, you'll need a rough idea of the weight of your vehicle. The motors and batteries will comprise the lion's share of the weight. I'd start by summing those weights. The marker and CO2 bottle will probably be next in line. You should be able to weigh those yourself or get approximations from the group. - Doug From: whitney james [mailto:[email protected]] Sent: Monday, November 30, 2009 12:47 PM To: [email protected] Subject: RE: [TANKS] Re: Complete Newbie... I personally support me having enough money to get a decent CAD program. :D As to the suspension parts: I suppose I have the "budget", it's just a matter of spreading it out over time. That, and I'm not sure if the made-for-it springs will handle the weight. They have different stiffness ratings, so I'll most likely wait until I have the basic structure assembled, throw in some weights to simulate the final B1, and then just weigh the whole thing, divide it out to weight per tire, run those numbers against the stiffest things I can find at a hobbie shop, and if they work: it's back to Ebay. If not... well, I'll have to find something else. Unfortunately, springs are a bit of a mystery to me. I have no clue how they're rated, distance of travel, compression rates, etc. So, it'll be very much a trial and error thing... Thanks! > Date: Mon, 30 Nov 2009 09:30:08 -0800 > Subject: [TANKS] Re: Complete Newbie... > From: [email protected] > To: [email protected] > > Well. I support cad. More accurate as you can put the motors in aswell > and my laptop which i run SU from can be taken about anywhere. Pencil > and paper: well i cant draw well but ive seen technical DRAWINGS and > they will get you where you want i > guess. Back to actual topic of > the APC. Suspension: if you cant find space in budget for commercial > suspension parts could you not make the build so its possible to mount > commercial parts and then use some cheap DIY setup. When some of it > fails replace with heavy duty commercial because by then the main > build will be out of the way so your budget should be freed up again > > On 30 Nov, 16:44, whitney james <[email protected]> wrote: > > All right, Wow! > > > > CAD Vs Pencil drawn: I think I've found the new blood sport! > > > > If I may hijack this MOST interesting conversation? (apologetic > > smiley face thingy.) > > > > Ahem. > > > > YEEE! > > > > (Ok, regain composure.) > > > > I've gotten my first set of parts in the mail! They came > > Sat, just 3 days after the ebay seller (integrajspec: these guys are creative > > with names!) said they had been send off. Very agreeable chap by the way! > > > > Well, I won't bother with pictures, as they aren't really > > attached to anything (or each other) yet, and you can easily see them online. However, > > as I'm sure you're all dying to hear about them (likely as not, you're not really > > all THAT interested, but it's a dull Mon and I have some time on my hands, so I'm > > going to do my best to bore you.) > > > > First off, the A-Arms. They're black (Oooo!), and there's 4 > > upper, and 4 lower arms in this package. Now all I need is that same number > > again. > > > > Not all that much remarkable about the color. Also, I'm not > > enough of a materials expert to tell whether they really are molded nylon or > > just nicely textured plastic, but they feel pretty tough and rigid. > > > > The upper arm is definitely thinner than the lower arm, but > > that's not a major issue as the weight is largely born by the lower arm. If I > > really torque it, I can get some twist out of it, and if I really put my back > > into it, I could probably bust it, but I'd rather not. J > > > > The lower arm is pretty beefy. I can't get any twisting > > movement out of it by hand, and the material is fairly thick: both sides of the > > arm are about as thick as my pinky. Not that I'd expect any of you to know how > > thick my pinky is, but you (maybe?) get the idea. It's also well designed, in > > that it's bowed upwards slightly, giving it good geometry to the task at hand > > with 4 different holes for mounting the shocks/springs/bouncy thingies. Still > > not sure if I want to fork over the cash for the commercial units, or if I > > should go with a custom setup. Still, the mounting holes are nice, and will be > > used. Length wise, they're pretty good sized; being about 4 inches long, and > > the widest (the upper) being maybe 2.5~3 inches wide. A fact I doubt you really > > care about. > > > > Next up, the bulkheads. They're gray. Gray and black go well > > together so I should have a nicely color coordinated undercarriage here. Ok... > > Too much information. > > > > They have what looks to be an equally good design, made out > > of the same material as the swing arms. They're also VERY tough, and I can't > > get any flex out of them by hand. They have two mounting holes on the bottom, > > which will be used to connect them to a base plate, and several other holes > > both through them in various directions which will be immensely useful for bracing > > them inside the B1 and building the rest of the body around them. > > > > They also have a very close fit with the swing arms, so > > there should be minimal bending stress on the hinge pins: only shearing stress. > > However, the pins are about the same size as a 10d nail (AKA: big enough to > > very effectively impale your hand or to be used as an average sized framing > > nail), so there shouldn't be any fear of them giving out. > > > > Right! That's it for this installment of the build. or > > rather this installment of the lead up to the build (Argh! This is going to > > take soooo long!), so you may now resume your regularly scheduled programming of: > > > > (in big loud booming voice.) > > > > CAD VS PAPER AND PENCIL!!!! > > > > (cheering fans in the distance..) > > > > Toodles, > > > > James > > > > _________________________________________________________________ > > Windows 7: It works the way you want. Learn more.http://www.microsoft.com/Windows/windows-7/default.aspx?ocid=PID24727.. . > > -- > You are currently subscribed to the "R/C Tank Combat" group. > To post a message, send email to [email protected] > To unsubscribe, send email to [email protected] > Visit the group at http://groups.google.com/group/rctankcombat _____ Hotmail: Trusted email with powerful SPAM protection. Sign up <http://clk.atdmt.com/GBL/go/177141665/direct/01/> now. -- You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to [email protected] To unsubscribe, send email to [email protected] Visit the group at http://groups.google.com/group/rctankcombat -- You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to [email protected] To unsubscribe, send email to [email protected] Visit the group at http://groups.google.com/group/rctankcombat
