This week I overcame the challenge that is making foam wings out of sheets of foam... hard to describe, you'll just have to watch it : )
I finally got it down and cut out two wings for the Raptor, taped em' up and got the electronics ready...See you next week!
-Trent
Comments
Hi Trent
You need the lamp and the transformer. I can send you a simple drawing if it helps ( not quite sure how yet)
As Petrus say the heat is proportional to the volts / resistance. my setup uses 20pound stainless fishing wire (better that Nicrome and CHEAPER) and 12 vols will power a 30 inch hotwire and 24 volt will power a 30/60 inch wire. I use a dimmer with a push on/ push off switch to maintain the good setting for the next cut.
Greg's comment about the gas is also very important..
Maybe we need a safety co-ordinator for DIY drones. I might just put my name down. !!
Brian: Sad to hear about the wing… must have been quite a sight to see that impact! I’ve tried the mono-coat on the cut XPS before and it wouldn’t stick very well, perhaps due to the “empty space” of the foam surface, or it could because I have no experience using the covering :) I’ll keep trying.
Hooks: I know, the servo’s are sub-par, but it’s all I got. I’m going to be picking up better ones soon.
Timothee: Thanks! I hope it flies well too!
Dave: Thank you! It’s getting there…
Dez: I know, not the best servo’s… better ones coming asap.
Greg: Yeah… that smoke is no good. You may know it actually puts off Hydrogen Cyanide gas, not good for your health for sure.
Petrus: You’re exactly right, ohm’s law dictates the amperes that pass through based on the wire’s resistance (which is constant for nichrome wire). Having the right balance of amps/heat will make a much better wing. The wing's got a little twist (about 3 degrees) I’ll have to show you in better detail in the next episode. Tell me a bit more about reflex, I’m not familiar with it in this context.
David: I didn’t know it was that dangerous! (my set up). I’ll add a lamp for sure! Thank you for the tip and your concern!
R.D.: Ha ha! You can send one if you’d like, I’ll try to improve it to David’s comments… I’d rather not die that kind of death.
David,
I am glad someone else saw the problem with Trent's wire cutter.
http://mygeekshow.proboards.com/index.cgi?board=general&action=...
The foam cutter supply on my bench is like the one described by you.
I will send Trent a supply if someone else doesn't beat me to it.
Hi Trent
I like your videos but I think you have a problem with your cutting method.
The 120v supply form the wall going to a dimmer switch is probably the most dangerous tool I have seen for a long time.
1. one end of your hot wire can be at 120 volts, it could be either end, this will kill you. We dont want that as we need more videos.
2. The right way to do this is to use the output from the dimmer to control a 40 or 60 watt lamp AND use the same lamp supply to power a 120/ 24 volt 3-4 amp transformer. the output from the transformer goes to your hotwire. The transfomer provides isolation from the mains supply and you do not die if you pick up the wrong end of the hotwire. 100% improvement. The lamp shows the hot wire is powered and also shows the dimmer is working, It smoothes the power going into the transformer. at the same time.
30 yrs as an electrical engineer tells me this is OK. I use this setup on my foam cutter .
Have fun
Trent, just to share my experiences,
1. The heat of the hotwire is directly proportional to the length and thicknes of the hotwire. I use a 12v 3 amp power supply and adjust the length of the wire for the correct heat
2. Dont use to much or too little heat to cut the foam.
3. As you have observed, having 2 pieces of foam glued together to make up for the thickness of the wing makes a perfect cut quite difficult. Either try to get the correct thickness of foam or glue after cutting
4. Ensure your template edges are smooth, any nicks will make the wire jump and provide a rough surface
I quite like your "vanishing point" method of making the cut by yourself, but this means it will be impossible to add wash out while doing the cut. Will you be adding washout or twist during the installation of your spars?
I also see an airfoil without any reflex( highly reccommended for flying wings), will you be flying elevons-up?
Trent, Please use plenty of ventilation when you cut blue foam. Put a fan behind you and open the garage door. Yhe fumes make you sneeze because they are very toxic, and to high of heat probably makes it worse. Protect your health.
Nice one trent.Please don't use them servos and don't rush too much dude id hate to see all that work gone.Looked bigger than i thought it would but that makes it even better.
I hope it will fly well!!
Nice job ;)
I have great results with this great servo from HK http://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=...
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