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RE: Here's a Simple & FREE First Foam Build Plan! Cool ... - 4/22/2006 5:45 PM   
critterhunter



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Status: offline 		Small update: Played with the bandsaw type cutter today. Used the thickest .022 diameter steel fishing leader I had. I figured, since this wire is so short, the 12V .2 to 1.2 amp variable setting was what I'd need to use. Turns out the variable amp mode on this charger no longer works even in the 6V mode. I figured it was fried years ago as the amp gage on the charger would give me no response when using it to charge a car battery. Either way, only the 6 amp static setting works in both the 6 and 12V modes. Since 12V at 6 amps was obviously too much juice for this table cutter, I tried the 6V 6 amp mode and it still is producing too much heat and getting the wire red hot. So, I'm forced to wire up the dimmer switch between the charger and the wall outlet to control the power. Not a bad thing since I would have to wire the dimmer switch up sooner or later when dealing with various small foam cutting hand tools I plan to make. Sometime today I'll wire up the dimmer and play with the dial to get the heat about where I want it. Then I'll mark the spot on the dimmer it should be set at for the table cutter and what diameter wire I'm using at that setting to keep things clear for future reference. As I build more tools and test them I'll also mark their spots on the dimmer dial and what gage wire they are using. Things are rolling along fairly well.


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RE: Here's a Simple & FREE First Foam Build Plan! Cool ... - 4/22/2006 5:57 PM   
Espresso-Outfitters


 

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Status: offline 		Glad to see you are really getting into this stuff, good luck on the freehand element, I've never been able to get it to cut correctly without jigs, even with a real bandsaw and regular wood, I can only get close, it always takes sanding to get it fine tuned, but then again, I use jigs even on the plywood so don't even use a bandsaw these days.

Looks like I'll be dusting off my foam cutter and creating others and setting up jigs and of course, mounting it to a motor to control it more consistantly. My current ARF supplier cannot handle packaging, so 4 out of 5 of my planes were broken in the box upon delivery due to his incompetency, when I finally made a sale, again, another broken plane, I was overcharged for shipping, and ended up having to pay almost as much for that element and getting the plane replaced then the cost of the plane itself, it's a shame since the end product is so nice, yet they don't ship well upon the final destination, so will be sending him right on back to China with his tail between his legs, you don't mess with this American business man. Soooo,,, look forward to me sending out planes to you guys, haven't received anything from fisher yet, perhaps he might get motivated if I send him one of mine, it's about time an American manufacturer shows these commies how it's done.

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RE: Here's a Simple & FREE First Foam Build Plan! Cool ... - 4/22/2006 7:33 PM   
critterhunter



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Status: offline 		Here's the dimmer control I just wired up. Works great with the bandsaw style hot wire cutter. Set the charger at 12V 6 amps and cranked the dial up on the dimmer to where the wire started to glow and then backed it off to a point where the wire was no longer glowing but was just hot enough to cut through the foam like butter. Ended up being about the 5 O'Clock position on the dimmer dial. This is good, as it means I've got plenty of room on the dial to crank up the power for larger cutter tools. Did a few practice cuts and it almost feels like there is no resistance to the wire moving through the foam at all. I put the dimmer into an outlet box but want to mount the whole thing onto some kind of board enclosure with the charger to keep things a bit more secure with less chance of getting a shock should a wire come loose in the outlet box. Rather than also wiring up an outlet plug box I simply cut an extension cord in half. Plug the dimmer into the wall and plug the charger into the other extension end and I'm am business. This also keeps things modular so I can use another power source in the future should this battery charger fail on me in the future, or if it turns out it isn't enough to power the larger bow for the wing airfoils...have to do some test cuts with it to determine that. I've also put numbers on the dimmer face to corespond to the tool being used. On the tool (such as the bandsaw type table cutter) I've put instructions in black magic marker for it's use..."Set charger at 12V 6 amps. Set dimmer to "1" on the dial using .022 diameter steel fishing leader." Hopefuly this will keep me from using the wrong settings and cooking a cutting wire or such.


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RE: Here's a Simple & FREE First Foam Build Plan! Cool ... - 4/23/2006 9:48 AM   
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Status: offline 		Glad to here you are making progress on this one, can't wait to see what you create, I'm sure you are just going to town on all of this once you get going upon formalizing jigs for everything.

I gotta show the new additions to my fleet, one is the Easy Cub, it's a rather strange ARf to assemble, on one end, there are elements and details that are more then covered in very high end extreems, on others, they just are ruthlessly primitave and you gotta really think on your feet and hope you have the extra doo dads to get it complete, overall, am happy with it's looks, utterly dissapointed with the fact I wasted an entire day I could be doing real production since the CNC work lacked, the other is a Tiger 400 I picked up used and pre-crashed, I bought it cheap to practice new manuevers, not worrying about destroying a pristine bird.

I'm going to put together a more traditional kit the next time I get back into balsa/basswood world, have a couple earmarked from hobby lobby, and put them into ARF format just to show how one in this nature can be done. Meanwhile, I'll have a few foam saucer ARF's I create in house "soon" will be giving out to any that are interested.

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RE: Here's a Simple & FREE First Foam Build Plan! Cool ... - 4/23/2006 2:24 PM   
critterhunter



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Status: offline 		Looking good. Hey, harbor Tool & Freight has a cheap 3 channel cub for like $89. I'm sure the electronics are junk but it isn't a bad looking plane.

Later today I'll be starting to cut out body parts. If I don't have a steady enough hand to cut out body parts with the bandsaw type cutter I'll make body jigs to follow. Like I said, going to save the wing for last as that seems like it will be the hardest part of the project. Still a question as to whether the large cutting bow will be hot enough to do the wing airfoil. After I've hacked out four or five bodies with success, flown it using a BP21 and 3 cell lipo, and understand more about what I'm doing, I'll begin work on the upscaled version for the 540 and Sub Cs. I can see that big monster all done up in P38 camo torking it's way through the sky!

Quick question...Are you guys having to do any sanding of the foam to make parts fit better for assembly? If so, what grit sandpaper are you using and does it destroy the smooth foam surface?


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RE: Here's a Simple & FREE First Foam Build Plan! Cool ... - 4/23/2006 11:23 PM   
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Status: offline 		I'll use anything from 220 - 600 grit sandpaper, the idea is to tread lightly when using it. You need to keep in mind, I've built several prototypes without using any foam cutters, just regular tools and alot of sanding so I have a good feel for when I'm pressing down too hard.

The harbor freight stuff is similar to parkzone stuff, it's cheap plastic and foam, no real quality and is meant only for the beginner, mine is a 4 channel, all cnc, balsa/plywood construction, too bad the manufacturers rep is clueless about shipping, I don't expect them to remain in business very long due to that element along, I had to do alot of fine tuning and retrofitting on this last one, that and there wasn't enough hardware to complete it so did alot of scrounging, in the end I ended up using the glue gun to get it together, being fed up with the fact this is supposed to be an ARF, didn't know it meant "almost ready to fail", hehe. I turned my buddy onto another one of these, his was broken upon delivery as well, you gotta love his return policy, he want's you to bring it over to Fed Ex for inpection, Fed Ex, not being liable for poor packaging refuses to compensate the buyer. You then have to pay to ship it back to the company, they in turn charge you again for shipping the replacement. My friend was overcharged 20.00 in shipping and still doesn't have a working plane yet. I will NEVER buy from some immigrant ever again. If he can't speak proper english, chances are he's going to be a nightmare to deal with and his ethics will be questionable. Go BACK to china Green RC models usa, you have messed with the wrong player.

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RE: Here's a Simple & FREE First Foam Build Plan! Cool ... - 4/25/2006 1:11 PM   
critterhunter



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Status: offline 		Made jigs for the booms and fuse yesterday then cut them out with the foam. Sanded them down a bit and they are ready to go. Also made a jig for the stabilizer but then realized I'll need thinner foam for it, the elevator, and the rudders. Will pick up some fan fold or some meat trays for that tonight. The plane designs say you can cut an airfoil out for them or use some thin foam. I don't want to bother with cutting airfoils out for anything more than the wing. One question I do have about the wing is the airleon...Do I have to cut this out of the wing and then use that piece (with it's airfoil) for the flap? I'm worried I'll screw up the cut out piece. I'd rather just cut it out and then use some fan fold as my airleon, or at least use fan fold if I screw up the cut out wing piece and can't use it.

So, have to use fan fold or some other thin foam to cut out the fins, stabilizer, elevator, and possibly the aerlion, then the only body part left to make will be the wing. After that it'll be time to assemble the plane, mark COG, and install the electronics. Coming along pretty well.

I am finding, however, that even with jigs to follow around the foam I'm having to do a good bit of sanding to get the surfaces flat. I'd also like to find some kind of belt sanding device I can lock into a flat surface so I can just run my foam over it and sand it flat and level. It's hard to get things level by hand...and if surfaces aren't level it's going to be more difficult to get the body parts straight when gluing together.


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RE: Here's a Simple & FREE First Foam Build Plan! Cool ... - 4/25/2006 4:30 PM   
Fisher



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Status: offline 		critterhunter,

Sounds like you are headed in the right direction. I ended up making an airfoil template for the horizontal stabilizer and vertical fins. Cut them out of the same foam. Worked fine. You can probably us something other than the piece of foam you remove from the aileron area for the actual aileron but the original foam works fine. I replaced the thin foam elevator with a piece of balsa wood and it really improved the response. These planes are so easy to build they give you the freedom to try different things. I just use a tri-square as a template to cut out the ailerons and away I go. Does not have to be perfect. The straighter you get this plane the better but it is very forgiving so do not sweat it if it not perfect. It will fly fine.


EO

I think the key to shipping these foam parts is to keep the cut away material and cradle the parts in it. Gives a perfect fit and acts as a sacrificial cushion. Spent all last weekend working with my son on a Floating Arm Trebuchet. Was lots of fun showing him how to use a table saw. Should be slinging missiles by next week.

As a friendly reminder, most of us are sons and daughters of immigrants. So gig the Green Models guy all you want for his poor business practices but belittling his language skills and heritage are a bit below you. I am always impressed that anyone can conduct any level of business with English as a second language. Once I learn Mandarin and start doing business in China I can start questioning his language skill etc....

< Message edited by Fisher -- 4/25/2006 4:34 PM >

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RE: Here's a Simple & FREE First Foam Build Plan! Cool ... - 4/25/2006 5:38 PM   
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I'm impressed by your foam cutter. I was asked to build one for someone.
I like the idea of using a battery charger. But I think a 'smart' charger would probably go nuts hooked up to a dimmer, so it needs to be an older one - no chips onboard.
I was thinking of running mine right off the charger's transformer, bypassing the electronics. I don't think you need them - AC should work fine, no?

Does the temperature stay constant, or does it drop significantly when you cut? There's not much thermal mass there to store heat, so I was wondering if I should consider making some sort of regulator circuit. Somewhere in my junk pile I have a surplus temperture control module I could use (replacing the dimmer), but is that just not necessary at all?

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RE: Here's a Simple & FREE First Foam Build Plan! Cool ... - 4/25/2006 7:17 PM   
Espresso-Outfitters


 

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Status: offline 		Fisher, when the immi"grunt" "s" think they can operate in the good ol USA with impunity, showing zero respect for how it's done in the states and worse yet, doing a dis-service to myself, hell yeah, I'm going to raise hell over it, especially since he's selling in RCU and wasted alot of my time and money, I want to make it very clear, you do NOT go through them for any reason unless you enjoy broken planes and feel it's necessary for us Americans to become another 3rd world country. Running along that tangent, what is worse is the fact that most speak very little, if any english, they don't pay taxes due to the screwed up system as well, every buck you spend at the foriegn owned convienence store for example results is at least 70% of the profits being tossed right back to their home land. You would think it should be mandatory they at least learn the language, it's mandatory to learn english everywhere else throughout the world, it's not like we would ever get away with opening up shop in china land without knowing chinese, I have zero respect for foriegners that think they can just open up shop and impose their losing standards and expect to get away with it. Check out how they treat their own population, worse yet the leather trade, it makes hitler look like a push over, you also may take note, this is an athiestic population as well, of course they cannot see past the nose on their face, there is nothing to this universe outside of that according to them.............

The more I get into dealing with these, the more incentive I have to open up a competing operation, taking back what is ours and sending these commies back to where they came from. Sorry if you can't handle my approach, but if I do not stand up for Americans, who will? Watching this economy going down the tubes because we rely upon foriegners, both from the fuel we use to the trinkets we buy has me greatly disturbed, we need to wean ourselves off of our dependance of them and take back control of our economy.

Packaging, man, it's common sense, use some tape, don't let the hardware just float around the box, again, back to respecting the end client, it only takes seconds to get it right, not sure why goober could not handle it, I guess common sense is not taught in these 3rd world countries....




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RE: Here's a Simple & FREE First Foam Build Plan! Cool ... - 4/25/2006 9:33 PM   
Fisher



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Status: offline 		Not sure how to respond. I think you have quite valid reasons for not being happy with the service you have recieved but I still think you are being quite bigoted with regard to your view of non-native business people. I think that the Good Ol U S of A has taken as much as it has given to many foreign countries. I think we are all simply looking for a better life. I will say no more on this point and begin packing my bag to return to my place of birth. Tachikawa, Japan.

Good Flying.

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RE: Here's a Simple & FREE First Foam Build Plan! Cool ... - 4/26/2006 2:12 PM   
critterhunter



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Status: offline 		I know this is off subject so I'll keep it short. I tend to be conservative in my views and in many respects worship the working model of capitalism. Capitalism works PROVIDED it's a self contained experiment. Meaning, demand sets price...whether the price be for products or labor. However, with all the illegals coming across the border from Mexico the price of labor is being upset and forced downward. The demand in the market is no longer setting the price of labor for certain jobs...What a company can get away with paying non-legals is. So, bottom line is many less ethical republicans don't want the border shut down because they want the cheap labor, and the many democrats don't want the border shut down because they want the potential votes and future power it will bring. In the middle we all suffer. Americans will do ANY job, from picking apples to shoveling crap, so long as the wage is raised to what they are willing to work for. Again, by allowing an outside source to upset the supply and demand relationship between the two they will never meet. Enough of that...

On the hot wire cutter. No, NEVER use AC to heat the wire. It's very unsafe regardless of how much control you think you have over the voltage. The wire doesn't loose heat as you cut provided you move at a steady slow to medium pace. If you try to rush the wire along too fast then it will cool a bit for a split second and begin grabbing at the foam. However, the wire heats up so fast (matter of seconds) when you first turn it on that it recovers quickly. Just back down your cutting speed a tiny bit or crank up the amps to compensate. Yes, I would think that modern chargers might get confused if they are computer controlled. Buy something basic (I hear Kmart has a good one for $25). I wouldn't worry about using a thermal control. A dimmer works great.

Fisher, thanks for the tips on the plane again. I'm going to keep the stabilizer and fins flat using a thinner foam. As for the airleon, I'll try to cut that thing out straight and use it on the wing first.

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RE: Here's a Simple & FREE First Foam Build Plan! Cool ... - 4/26/2006 5:58 PM   
khalsans


 

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Status: offline 		Thanks for the tips on the heater. If the wire heats up very quickly, then a temperature regulator is not much help - they tend to respond to input in seconds, not milliseconds. I fought that problem here at the Lab in Los Alamos with a themal bonder that had electric heating elements.
I'd set the temp to 150 degrees, and the element would overshoot to about 500 degrees in the first 6 seconds.
KISS! - works for me.

I have some nichrome wire, good for heating, but I suspect that the steel is better for cutting, so I'll try that first, unless you think otherwise.

I think you misunderstood me on the AC - I was talking about tapping the secondary side, the low-voltage, isolated side of the transformer in the charger. You are quite right - never tap the mains - you could kill somebody with the exposed AC.

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RE: Here's a Simple & FREE First Foam Build Plan! Cool ... - 4/27/2006 9:56 AM   
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Status: offline 		I'm ordering the real deal power source and bow next, it will be nice to have precision.

Fisher, no comments were meant about immigrants, they were focused upon those that wer exploiting the situation, you have to admit at seeing foriegn owned operations that only hire from their home land rather then locally, most american op's abroad are happy to hire the locals, we really bring capitol and opportunity throughout the world throughout it all when it's all said and done. My stance is strictly based upon wanting to keep the usa, the usa, not the us of some other country, after all, this is the reason it's the place many want to immigrate over to here, if it was just an emulation of their home land, there is no point in even bothering, and what "bothers" me is the fact that we not only have a few op's trying to make it an extension of the home land, they are doing so further into our neighborhoods. I don't care where you were born, what color of skin or religious affiliation, once you are an American citizen, your loyalty remains with America, not the former residence.

This is the last post I make about this subject, do NOT reply to it's context unless it's a post about going to another thread you created, it has zero to do with the original context, free foam flier...........

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RE: Here's a Simple & FREE First Foam Build Plan! Cool ... - 4/27/2006 4:37 PM   
Fisher



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Here is the next project. An Aero Ace converted to a Miss Hydro. Looks Like the SO could be modified to work in a similar fashion.


This gent seems to be in EO's league with regard to mixing construction strategies. Some very good photos of the process. Looks like he just uses a band saw to cut the EPS.

http://www.rcgroups.com/forums/showthread.php?t=490001&page=2&pp=15


http://www.rcgroups.com/forums/showthread.php?t=492873

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RE: Here's a Simple & FREE First Foam Build Plan! Cool ... - 4/27/2006 9:53 PM   
Fisher



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http://www.rcgroups.com/forums/showthread.php?t=508902&pp=15

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RE: Here's a Simple & FREE First Foam Build Plan! Cool ... - 4/28/2006 2:32 PM   
critterhunter



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Status: offline 		Fisher, very cool looking stuff. You've got to just love those little Aero Aces. I now have two...one I'm keeping stock and another I've experimented with. Slitted the nose and moved the lipo forward to compensate for the tail heavy problem. I then removed the lower wings and flew it that way for a while too. However, doing this makes it too fast to fly in the barn several of us fly them in. I then yanked the electronics out of it for an install into a little Harbor Tool & Freight Cesna (pretty plane). Only one outing with it in windy conditions and only managed a few circuits before a crash. I'm sitting that body aside for now until I learn more about building little planes with the AA guts. Right now I've got some space shuttle foam bodies (.99 cents) from a local hobby store to stick the guts in and try. Can't beat the value you get (tx, two motors, built in tx charger, lipo battery for LONG run times, and a proportional tx control) for $29 (Toys R Us or Target). We've had great fun with these little buggers. I like to fly mine if I'm waiting on a battery to charge on my other "real" RC planes.

Nichrome wire, the way I understand it, has more resistance than stainless steel fishing leader and thus will heat up more. This can be an advantage. If I'm thinking right my 40" bow would probably get hotter if I used it instead of the stainless steel I'm using now. I can't got any thinner in diameter (.018) in the steel wire for the bow or I risk breaking the wire. The .018 diameter wire is only raited at like 69 pounds. When the wire gets hot it weakens so I don't want to try anything smaller...but smaller would get hotter due to more resistance. I think this .018 size is going to work with the bow...just have to try it.

Right now I have the fuse and booms cut and sanded. I'm waiting to track down some thinner foam for the stabilizer and fins. I'll either hit Home Depot for some fan fold, thinner "pink" or "blue" foam, or just pick up some meat trays at the supermarket to use. I've got wood templates (jigs) cut for the fuse, booms, and stabilizer so far so I can just trace around the wood outline with the wood laying on top of the foam as I guide it through the bandsaw type hot wire cutter. After I cut my wood (handy board...3/4th inch) templates using a jig saw I use an orbital sander on them to smooth them out. Still, it's hard to get these cuts at 90 degree angles on the wood, and the foam doesn't exactly come out perfectly cut at 90 degree angles either. So, I then use some 210 gritt sand paper on a sanding block to smooth out the cuts on the foam and try to eye them flat as possible. Still, I'd rather find a way to sand the foam down to a perfect 90 degrees. I was thinking a belt sander locked into some kind of device that I could run the foam over to sand it perfectly flat. Or, I could at least lock the foam into some kind of straight edge and then sand it down until it is flush.


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RE: Here's a Simple & FREE First Foam Build Plan! Cool ... - 4/28/2006 4:50 PM   
Fisher



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Status: offline 		Critter,

There was some detail on one of the hot wire pages we have looked at that showed a straight edge cutter. It ends up using a hot wire bow as a chop saw. I used that strategy for all my straight cuts and it works pretty well. If you can get enough tension on your hot wire band saw and the wire is square with the base vertically then you should get square and true surfaces. You can use heavier wire on the shorter bow to increase the tension and maintain strength. You already know that you have enough power to heat up a thicker wire. I have found that time spent getting the hot wire to do the cutting right the first time saves a whole lot of hand sanding etc...

I need to find a micro BL system like the BP-21 stuff that would work for smaller indoor fliers. They I might start fiddling with smaller stuff like this. My pea sized brain holds me back most of the time.

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RE: Here's a Simple & FREE First Foam Build Plan! Cool ... - 4/29/2006 2:47 PM   
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From: Brook Park, OH, USA
Status: offline 		Fisher, there are brushless motors in the size class of the AA (and smaller) on the market now. Check RcGroups in the micro and indoor message forum.

My cuts with the bandsaw style hot wire are pretty straight. If you look at my photos of it I used a bolt at the top and a bolt under the table that the wire is attached to. This allows me to adjust where the wire sits via nuts and washers to get it straight. Still, the spring I have on it is a little too weak and when I'm running cuts the wire tends to bend around the wood template a bit if I get too close with the wood, pushing on the wire.

Yesterday I tried going to an even smaller steel fishing leader than the .018 (think I used .012 or somewhere around there) on the 40" bow and it still didn't get hot enough. In fact, the wire cut worse as it's so thin now it won't hold the heat long as the foam cools it. So, I've obviously got two options...Dig up some nichochrome wire (which should get hotter than the fishing leader) or replace my old car battery charger with something using a higher voltage and/or current. I suspect the old battery charger is not putting out a true 6 amps because 12 volts at 6 amps should be more than enough to power a 40" bow from all I've read. In fact, 12v 2 amps seems to be the most used power level by various hot wire cutter designs. Either way, I think I'll try digging up a new power source with more amps or volts. I just read a blurb about people using a 25v 2 amp transformer from Radio Shack for $10. It's not in a case, but rather a bare component (just the transformer with a few wires coming out of it) and that's why it's so cheap. Perfect if they still sell the thing. If I can't locate that I'll hit the Kmart, Sprawlmart, and Harbor Tool to see if they have a car battery charger with more amps an no computer circuits to confuse. I'd figure a 8 or 9 amp battery charger would be more than enough juice to fire the bow. Or, as said...the 25v 2 amp transformer should work as well because the voltage (force) is much higher.

Could not find some meat tray foam at the local stores that was big enough and was unwilling to pay $36 for a huge stack of blue fan fold from Home Depot. So, went up to the local supermarket and asked the Butcher department if they had any used foam meat trays I could have. Lady came back out with 5 of them for me. Nice, flat foam with the perfect thickness for the fins and stabilizer. As for the elevator, I plan to use balsa or some salvaged F27 Stryker airleon (or verticle fin) foam to cut it out of . This stuff is stronger than the meat tray foam and should put out with the forces put on the elevator.


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RE: Here's a Simple & FREE First Foam Build Plan! Cool ... - 4/29/2006 4:25 PM   
critterhunter



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From: Brook Park, OH, USA
Status: offline 		Was just up at Radio shack and the indicated transformer is an AC output unit. Too bad as $10 is a good deal but I don't want to risk using AC for the output, even if it is only 25v at 2 amps. Looks like I'm off to look for a battery charger in the 9 amp or so range.

By the way, Radio Shack now has a new helicopter, a smaller version of the Bladerunner II for $49! Heard good things about Bladerunners and may have to pick one up soon. Lipo powered, 2 channel, "full control", etc.


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RE: Here's a Simple & FREE First Foam Build Plan! Cool ... - 5/1/2006 9:46 PM   
Fisher



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From: Anchorage, AK, USA
Status: offline 		Critterhunter,

Sorry you are having so much trouble getting the bow set up. I must have just had a streak of good luck with mine. You are on the right track. Hang in there.

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RE: Here's a Simple & FREE First Foam Build Plan! Cool ... - 5/3/2006 12:30 AM   
critterhunter



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From: Brook Park, OH, USA
Status: offline 		I've just had success a few minutes ago cutting out my first wing and it aint half bad! As said, I believe the old battery charger I have is just too weak even at 12V 6 amps for the 40" bow. I tried .012, .018, and .022 diameter stainless steel fishing leader and none of them would get hot enough with it. In fact, the .012 diameter wire was the worst in producing heat, which goes against logic since a thinner wire should have more resistance trying to carry the same amount of amps and thus heat up more. I think it just isn't thick enough to hold the heat for more than a split second when the foam touches it and cools things down. The bandsaw style table cutter using the .022 diameter wire is working fine with the old charger at 12V 6 amps using a dimmer switch to control the power output.

Anyway, I did some battery charger shopping over the last few days...Kmart, Sprawlmart, etc. Nobody had a basic charger (without a computer to confuse things) with the amp output I was looking for....Something in the 10 or more amp range. Today I stopped at Harbor Tool & Freight and they had a Chicago Tool charger on sale for something like around the $29 range. My niece works there so I get the sale price plus another 20% off. She gets the sales price plus the 20% discount even if the item is not on sale at the moment. Needless to say I get some killer deals on their already great prices. I believe the charger went for around $25 when all was said and done.

This charger has a 12V and 6V setting. 12V is an "automatic" mode. I didn't let that scare me away as I'll explain in a minute. The charger can be set at 2 or 10 amps for the 6 or 12V. It also has a 55 amp "starting" mode which is used to jumpstart a car rather than charge the battery. I figured something had to work on this thing for my needs, even if I had to use the 55 amps and the dimmer to lower the power output. Long story short all the modes do work with a hot wire, but none of them had enough juice to heat up the bow except for the 55 amp mode with no dimmer (at full power). Now, I'm not saying something in the 6 to 15 amp range at 12V won't work with the bow needed to cut this foamies wing out. Obviously you guys used lower power than 55 amps and got by fine. I would guess the stainless steel fishing line I'm using just needs excessive amounts of power to get it hot enough on a 40" bow. Anyway, the 10 amp setting will get the wire just about hot enough to cut with but I have to move a bit slower than I like. Perhaps it would be a better choice as there would be less heat to risk deforming the foam should you pause for a second while cutting.

So, I have a few pictures to show off to you guys. Keep it mind that this was my first real attempt at cutting out a wing so it does have one or two flaws where I didn't keep the cutting wire completely parallel on the airfoil jigs (one got ahead of the other for a second or two). However, a little sanding and she'll be good to go.

I'd also like to pass along a quick couple of tips to others who are new to this like me. For one, when cutting out the wing square that you plan to load into your airfoil jig board, cut it out a bit bigger than it needs to be (follow the outsides of your traced lines on the foam). While I'm using wood jigs to help guide my hand and trace around with the bandsaw when cutting out the booms, fuse and stabilizer, I didn't use a wood jig to cut out the wing. Just cut it out by hand with your bow or bandsaw type cutter and make it a bit bigger than it needs to be. Reason being that when loaded into the wood board/airfoil jig it will snug it's self from end to end (between the airfoil jigs) without the need to hold it by hand or use tape. The second reason to cut it out a bit bigger than it needs to be is your airfoil jigs will cut off the excess at the front and back of the wing so long as you have your jigs positioned to end flush with the board they are mounted to. Too much foam is not a problem, too little foam and...

One other tip I'd like to pass along to anybody using the bandsaw type cutter. This first wing had a nasty little notch in the foam right at the trailing edge of the wing that I didn't notice until after I cut it's airfoil out. Rather than live with it or cut out another wing right away, I wanted to try a perfectly straight cut down the wing at it's trailing edge, shaving off just a centimeter or two of it. I simply picked up my T-Square ruler and placed it on the bandsaw surface. Since the table top is perfectly square, the T-square has a good guide to make it's position perfect. Laid the foam on the surface and adjusted the T-square to a point where it would guide the foam for a perfectly straight cut, shaving off just enough of the trailing edge to get rid of the blemish in the foam. This worked so well that I might get rid of my wood jig templates when cutting out various straight body parts. Simply slide the foam along the T-square and it'll be straight as it gets. Your only worry is that the bandsaw cutter's wire is straight up and down in relation to the table surface, and if you use two bolts as I described a few messages back to hold the wire it's a snap to get it right. Best part is that only needs done the first time you hitch the wire to it.

Anyway, here's the pictures as I slowly make progress. The plane isn't assembled, just placed the parts upside down on the ground in place. Notice the stabilizer (meat tray foam).


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< Message edited by critterhunter -- 5/3/2006 12:38 AM >

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RE: Here's a Simple & FREE First Foam Build Plan! Cool ... - 5/3/2006 12:32 AM   
critterhunter



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From: Brook Park, OH, USA
Status: offline 		And the airfoil...Man, this camera blows...


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RE: Here's a Simple & FREE First Foam Build Plan! Cool ... - 5/3/2006 5:39 AM   
khalsans


 

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From: Santa Cruz, NM, USA
Status: offline 		I'm amazed at the 55 amp output not getting it hot enough. Perhaps your connections are high resistance? At 55 Amps, just 0.1 ohm of resistance in a connection will drop 5.5 volts. You'd need really heavy-gauge wire to hannde 55 Amps - #6 gauge, I think.
I think you must be current-limited by the charger somehow. Otherwise, you're close to having a welder there!
Not sure why you wouldn't use the Radio Shack transformer - once you are on the secondary side, you are isolated from the mains, so there's no danger of getting killed. You could put two of them in parallel to get more current.
An old toaster is a good source for nichrome wire. Hair dryers can be, too.
If you live close to Dayton (you are in Ohio, right?), go to the Ham Radio convention there in a couple weeks (http://www.hamvention.org) and pick up a big filament transformer from the electronic flea market there. I used to go there as a kid and drag home trunkloads of electronic crap. Drove my parents nuts.


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RE: Here's a Simple & FREE First Foam Build Plan! Cool ... - 5/3/2006 1:32 PM   
critterhunter



Posts: 2722
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From: Brook Park, OH, USA
Status: offline 		The 55 amp on the .022 diameter steel fishing leader is getting the wire plenty hot enough. But you're right, I would figure 55 amps would toast the wire in a heart beat. I can only figure, like you said, that the charger is self limiting in some respect. It does have an amp gage on it and is only showing reading at about 1/3rd up on the dial. Didn't pay attention but think it is putting out in the 5 amp range or so. Either way, I'm not going to fix what aint broke. It works and that's all I care about at the moment.

Once I get this thing assembled and flying I'm going to start work on the 540 brushed motor/Sub C version. I have the formula for upsizing it around here somewhere and once I've begun I'll post info and photos. I think Fisher is right that it will be easier to build the huge wing for this monster in two parts and connect them via carbon rods. There is no way I can build a bigger bow than I already have for the smaller stock version as per the power problems I've had.

A couple of small questions for Fisher on his build. I noticed you used the wing "fairing" (whatever) piece shown in the original plans that sits between the wing and the top of the fuse. What exactly is it's function? Don't see why I can't just glue the wing to the top of the fuse and be done with it. I suspect it's just to better the airflow between the wing and the fuse or perhaps to hold the wing better? Also, for your vertical fins...Did you slot your booms and glue them in there or just glue the fins to the top of the booms? Foam Flyer also doesn't mention where he's sticking the elevator's servo. Are you mounting it in the wing to match the aileron's position or are you mounting it in the boom right at the elevator? I'm also a bit lost as to how to par things up to be straight when putting it all together. Where to start is my problem. Use a T-square to match the booms to the wing, then use them as a reference to put the fuse on, etc? I know, as the original designer said, getting things straight is the most important part of this build.


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