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Deepend
Feb 18, 2010 8:19:57 GMT 10
Post by sean on Feb 18, 2010 8:19:57 GMT 10
The thermostat arrived yesterday, I wired it up and tried it out. It's a pretty cool little unit and didn't cost much. It took a while to position the sensor probe so it measured accurately - I hooked it up to my cheap blower heater and put it inside the hotbox. The sensor is very sensitive - I ended up wrapping it in a little paper towel and this seemed to stabilise the reading. The blower heater had trouble getting the box up over 55C. In contrast three 100W light globes running continuously would get the box up to 65C and I can use a max of four, though it takes a while to heat up with the globes.
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Deepend
Feb 18, 2010 9:08:56 GMT 10
Post by bananaman on Feb 18, 2010 9:08:56 GMT 10
There's an interesting article on microwave curing. LC3600 comes out the best. 90degC for 75sec using @2.4Ghz gives good results. Yes 75seconds! The whole report is here. www.kjbengineering.com.au/curep.pdfJust need to boost the output of the transmitter 2 or 3000 times or so and contain it so you don't cook yourself. Imagine the workshop production rates
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Deepend
Feb 18, 2010 9:58:25 GMT 10
Post by skyboyken on Feb 18, 2010 9:58:25 GMT 10
Just call in the roving band of 2-3000 2.4GHz enthusiasts and get them to stick their antennas into your hotbox!
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Deepend
Feb 25, 2010 20:03:17 GMT 10
Post by sean on Feb 25, 2010 20:03:17 GMT 10
A bit more progress has been made - the spar is finished. With a web made from solid resin mixed with chopped glass it's come out at 930g. Seems pretty strong and also pretty stiff. After adding various weights I tentatively tried standing on the centre of the spar with the spar supported about 2/3 or maybe a bit less of the way out to the tips, deflection seemed pretty slight - maybe 10-15mm but seeing as I was balancing above the spar I couldn't measure exactly. A very unscientific test but gives a lot of confidence in the strength of the spar. The spar does get flexier out towards the tips where it gets to be quite narrow, but the loads on the tips in flight will be pretty low compared to the loads at the centre. Resin/chopped glass web This pic shows 24KG of lead in centre, with spar supported a little inboard of the tips. Comparison with Tracer joiner. Tracer joiner is 12mm in depth, Deepend spar 20mm. Making the web turned out to be a pretty fast, straight forward job. I've added a fair few pics to my blog showing how it was done: www.rcgroups.com/forums/showthread.php?p=14442000
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Deepend
Feb 25, 2010 20:03:27 GMT 10
Post by aussiejarred on Feb 25, 2010 20:03:27 GMT 10
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Deepend
Feb 25, 2010 20:04:09 GMT 10
Post by aussiejarred on Feb 25, 2010 20:04:09 GMT 10
ahahahaha, LOL! we posted at the same time haha thats hilareous!
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Deepend
Feb 25, 2010 20:07:53 GMT 10
Post by sean on Feb 25, 2010 20:07:53 GMT 10
Haha! Thanks Jarred. Did you have a good fly this arvo? Except for a brief dry spell around lunch it was pouring all day at home so I stayed in.
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Deepend
Feb 25, 2010 20:11:59 GMT 10
Post by aussiejarred on Feb 25, 2010 20:11:59 GMT 10
yeah dude, we had great time.... sitting in our cars the whole time in cloud, and rain :S
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Deepend
Feb 25, 2010 20:17:34 GMT 10
Post by sean on Feb 25, 2010 20:17:34 GMT 10
Bummer! I was hoping it would be better over there but I guess not. We might have some luck over the weekend, fingers crossed.
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Deepend
Feb 25, 2010 21:33:18 GMT 10
Post by ezza on Feb 25, 2010 21:33:18 GMT 10
Wow Sean. That should be strong enough. Thanks for posting pics. Eric P.S. Thats alot of lead you have there, is that for the nose weight?
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Deepend
Feb 25, 2010 21:43:54 GMT 10
Post by sean on Feb 25, 2010 21:43:54 GMT 10
LOL! I hope I don't need that much but you never know. Andrew got those lumps of lead from a scrap metal dealer near Redcliffe for a good price. Only problem is they're so big I don't know how to make them smaller, would take ages to melt and can't cut them. They're great for building though, you can use them instead of clamps for some things.
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Deepend
Feb 25, 2010 22:35:34 GMT 10
Post by thevon on Feb 25, 2010 22:35:34 GMT 10
Sean, one day I decided to try cutting the lead ingots with my woodworking dropsaw, and it worked great! Really easy. As you can see in my pics I have cut mine into bits, each about 5kg.
But if you do it, make sure you wear goggles and stand out of the way of the blade's arc ... instead of sawdust you have lead shot shrapnell getting sprayed about, and it hurts! If the saw has a dust bag you'll have great lead shot for molding nose weights.
Metal recyclers often have heaps of lead and it only cost about $1 per kg.
By the way the metal dropsaw wouldn't cut it!
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Deepend
Feb 26, 2010 20:30:05 GMT 10
Post by sean on Feb 26, 2010 20:30:05 GMT 10
$1/KG is a huge saving over what it would cost anywhere else! Unfortunately I don't have anything as industrial grade as a drop saw. Here are some pics of the spar being stood on. I have it supported at 2/3 of the way out, so there's 1.4M between the supports. With it completely taking my weight, I measured the deflection at 40mm (I weigh 80-85KG). A bit more than I thought before. Trying to balance on the spar I could feel it flexing up and down as my weight moved around. The spar is undoubtedly very strong but I must admit I thought it would flex a little less than this under my weight. The bend in the first pic looks more extreme than it is - the spar has 2.5 deg dihedral (per side if you know what I mean). The second pic shows the spar upside down, so the bend doesn't look nearly as bad. When built into the wing, the wing skins should contribute some extra stiffness. Upright: Inverted:
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Deepend
Feb 26, 2010 21:18:18 GMT 10
Post by aussiejarred on Feb 26, 2010 21:18:18 GMT 10
haha dude, thats so cool! you gotta make that your profile pic
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