Drewrt

I studied gasification and saw a lot of good info on heat treatment of wood, a long time ago, both are fields in which a lot of great research was done, but little has made it to the digital age. In general I think that the carbon in wood, in the presence of oxygen starts to break down around 400-450, and torrification is done closer to 300. I'd suggest that an easy way to try to get consistent treatments for small amounts of wood to sample is to use hot sand. Use clean dry play sand, heat in your oven to desired test temp. This will take a while, and I'd suggest two large baking pans, bottom one half full top one 2/3 full. Have a larger box ready, sized so that the baking pan will neatly sit in the middle with a couple of inches per side. Pour 4" or so of perlite in t...

I studied gasification and saw a lot of good info on heat treatment of wood, a long time ago, both are fields in which a lot of great research was done, but little has made it to the digital age. In general I think that the carbon in wood, in the presence of oxygen starts to break down around 400-450, and torrification is done closer to 300. I'd suggest that an easy way to try to get consistent treatments for small amounts of wood to sample is to use hot sand. Use clean dry play sand, heat in your oven to desired test temp. This will take a while, and I'd suggest two large baking pans, bottom one half full top one 2/3 full. Have a larger box ready, sized so that the baking pan will neatly sit in the middle with a couple of inches per side. Pour 4" or so of perlite in the large box. Take the 1/2 pan out of oven and sit in bottom of box. Place wood on top, quickly pour 2n pan on top, then 6" of perlite. Wait 12 hrs, wood will be thoughly cooked to exactly 300, or whatever temp you raised the sand to, but no more. Have used this in heat treating, and in dewatering wood samples. As I understand it one of the goals though isn't to get rid of all the volatiles, but to stabilize many of them into waxes and resins.

Great Project Honus!! Very practically done. I've been thinking about doing something with a similar but bit larger build. I think you might find some of my work interesting, including some idea's on how to integrate 3D printed parts, with pretensioned wire and polymer reinforced hard plaster. If you are looking for an interesting next project to work on, we should talk. https://www.instructables.com/member/Drewrt/instructables/

Hi Crom, Thanks, my testing of it confirms for me that it is of higher efficiency than my last turbine, which was indpendantly tested to Cp 0.29-0.31, and it self starts reliably. This makes it between 50-100% better than the Gorlov varieties and as much as 300-500%% the energy collection of a Savonius (Cp, 0.05 -0.10 google Ian Ross, wind tunnel blockage for why Sav is so low, when so many wind tunnels have rated it closer to Cp 0.2). I’ll dig up the .stl and maybe see if I can easily create a version of it that you can edit easily. If I were doing this again, I’d make this part from a water jet cut sheet with the top section being the center, and folded down to form sides with cutouts and bend tabs to join. Ahh, I wish I had more time, more hands, or clones....

Hi Crom, I've added the .stl for the core print, as well as for it's 6 (3 sets of 2) "wings". I've also added the .step for the core part if you choose to redo it in sheet metal. I'd create a 3 or 5 panel sheet, with the top, and both flat sides, then flanges to join to a bottom plate, which if steel can be the back plate for one side of the alternator. The angular edges could be tabbed and bent, so the skins can fasten to them. It doesn't have to be as complex as I've made it. I'm open to supplying more help, but I'd like to know more about who, where, and when the build is.

With the layout I’ve done, I used about 60% of one 4ftx8ft sheet of mahogany door skin plywood. As I’ve said previously, I didn’t release this as a complete instruction set, more as a pointer in a direction, and I still suggest waiting till I release the next set of plans. If you want to move ahead sooner, then I suggest visiting with some people who’ve built stitch and glue kayaks. That is the closest analog construction I can think of and if you show them a photo of what you are trying, they may have some very handy tips. As to how to bend the plywood to the correct angle, yes, I worried about that too. In fact the larger issue is that the plywood hinges can tear pretty easily, but as long as they remain intact, then it will only go together when the angles are right, so y...

With the layout I’ve done, I used about 60% of one 4ftx8ft sheet of mahogany door skin plywood. As I’ve said previously, I didn’t release this as a complete instruction set, more as a pointer in a direction, and I still suggest waiting till I release the next set of plans. If you want to move ahead sooner, then I suggest visiting with some people who’ve built stitch and glue kayaks. That is the closest analog construction I can think of and if you show them a photo of what you are trying, they may have some very handy tips. As to how to bend the plywood to the correct angle, yes, I worried about that too. In fact the larger issue is that the plywood hinges can tear pretty easily, but as long as they remain intact, then it will only go together when the angles are right, so you can’t really go wrong, except by tearing the hinges. One thing I might do to help make the hinges stronger is to start by printing the templates on heavy duty paper, then glue the templates to the plywood, so the paper can be part of the hinge. The glue saturated paper makes a much stronger hinge than the plywood fibres. I’d glue paper to both sides (one side template), cut to the template, then just transfer the score lines needed to the far side. Also, I used a box cutter and a lot of patience to get the scores cut. A much better job could be done much faster with a router/trimmer, and then a wider flat bottomed cut could be made. A 3/16 flat bottomed grove cut through the top and core layers of the plywood (2/3 of 1/8 ply+ paper 2 sides, you do the math ) would make a much better hinge. I might also pre drill wire tie holes.

Hi Novice 3dp, yes, I see now that I've exported the wrong .dxf. Where are you located, and are you planning a build, or just an information collector :-) ? I've not got a lot of time right now, and while I'd like to support a Maker, I have to prioritize my time. It's a pain for me to get back to that project right now, so I'll put it on my list of things to do, more info from you might get more priority on it. This was just a test project, and it actually worked better than I'd expected, not really a set of plans. I'll have a new version for sheet metal, with connecting tabs, and precut rivet holes. I'd suggest holding off a build. But, If I recall correctly the .pdf's are cropped, but the two parts fit together, so if you print out 2 pdf's then cut out all 4 parts, 2 sets...

Hi Novice 3dp, yes, I see now that I've exported the wrong .dxf. Where are you located, and are you planning a build, or just an information collector :-) ? I've not got a lot of time right now, and while I'd like to support a Maker, I have to prioritize my time. It's a pain for me to get back to that project right now, so I'll put it on my list of things to do, more info from you might get more priority on it. This was just a test project, and it actually worked better than I'd expected, not really a set of plans. I'll have a new version for sheet metal, with connecting tabs, and precut rivet holes. I'd suggest holding off a build. But, If I recall correctly the .pdf's are cropped, but the two parts fit together, so if you print out 2 pdf's then cut out all 4 parts, 2 sets of 2 parts attach together to form each sheet.

What feature would a glove need to be helpful? Could it just damp out the tremor by being heavy? If tremors are worse when watching, does a cup with a lid make a difference? I wonder how the hand held camera stabilization arms would work? Have you seen this stabilized cutlery? https://www.amazon.com/Liftware-Steady-Starter-hand-tremor/dp/B00JDSIOJE

I agree Joshua. I wish I had more time and maybe a few clones! I will return to showing these can be made from renewable materials. Next though is to show a very simple method for building them from sheet metal, after I've done a bit of testing on this model.

Fun, I wonder how hard it would be to level this up, and be able to control the pupil secretly, so that the wearer, or someone nearby could control the view direction and look like they are tracking....

Hello Terezkaterka, I used google translate to interpret your comment and got "seems endlessly difficult". Not really sure what you meant, or how close the translation is. I did find this one difficult to build, but it's the first one, and it'll get easier as more gets figured out.

Thanks, I'm glad you like it. I'm not sure how/where you would use it on a motorhome. Eventually I'll be making a telescoping version of my turbine, but I've got quite a few other things on my list first

I don't see how to integrate this into a bus at this stage. It might be possible later when I do a telescoping fabric version.

I have never seen test results from the pop bottle, or squirrel cage type multi blade rotor, though many people on the internet have claimed they work, they also seem unwilling to comment on how well they work. As we've got no data on the pop bottle, I'll suggest that it's unlikely to be better than the historical Savonius turbine, which though the Blackwell report from the 70's claimed up to 21% efficiency, this number has never been real world verified, and many people who've built Savonius's expecting 21%, found it collected a fraction of that. Most recently in 2010, a researcher (Ian Ross, Wind Tunnel Blockage Correction factors) working to understand why Savonius, and other VAWT's were testing in wind tunnels much better than the real world results. He found that the blockag...

I have never seen test results from the pop bottle, or squirrel cage type multi blade rotor, though many people on the internet have claimed they work, they also seem unwilling to comment on how well they work. As we've got no data on the pop bottle, I'll suggest that it's unlikely to be better than the historical Savonius turbine, which though the Blackwell report from the 70's claimed up to 21% efficiency, this number has never been real world verified, and many people who've built Savonius's expecting 21%, found it collected a fraction of that. Most recently in 2010, a researcher (Ian Ross, Wind Tunnel Blockage Correction factors) working to understand why Savonius, and other VAWT's were testing in wind tunnels much better than the real world results. He found that the blockage calculation used on conventional turbines returned erroneous results, and that the more likely real world efficiency for the classic Savonius turbine is only 5%! My previous turbine, while under observation from an engineer, tested between 29% and 31%. It's likely that the pop bottle is less than 5%, and I'm hopeful that this turbine will be in the 30% range, so you could say that for every 1 of mine you need 6 pop bottle types. Pop bottles are cheap, but good alternators are not.

Thanks JonathanS365, I am glad you understand the wind shift problem conventional turbines face. Another advantage is that the foil profile is deep, and will tend to average out turbulence, where a thin bladed turbine would stall. The pop bottle is a good example of someone who understands half the problem. People focus on “catching” the wind, which I think is understandable. Another thing to consider is the letting go part :-). .. If a volume of wind has X amount of kinetic energy embodied it, and you extract 100% of that energy, you now have stationary air. Something needs to move that air to make room for more turbine exhaust. A key to very low Reynolds number airfoils is fineness, thought they may sometimes have a lot of camber, they are generally thin and sharp edge...

Thanks JonathanS365, I am glad you understand the wind shift problem conventional turbines face. Another advantage is that the foil profile is deep, and will tend to average out turbulence, where a thin bladed turbine would stall. The pop bottle is a good example of someone who understands half the problem. People focus on “catching” the wind, which I think is understandable. Another thing to consider is the letting go part :-). .. If a volume of wind has X amount of kinetic energy embodied it, and you extract 100% of that energy, you now have stationary air. Something needs to move that air to make room for more turbine exhaust. A key to very low Reynolds number airfoils is fineness, thought they may sometimes have a lot of camber, they are generally thin and sharp edged. At its widest a conventional Savonius rotor is 100% solidity and at it’s narrowest, 50%. Mine is 100%, then 20-30%.

Hi Victor, Thanks, I hope I can get an MPPT strategy to work. There are a few options. It turns out there’s some very inexpensive Chinese made controllers which may use a different, auto sensing MPPT strategy. There is a sort of automatic or governed transmission for these type of alternators, where as the turbine sped up, centrifical weights would move the magnet plates together, increasing flux density and output. I’d love to work on that someday,

I hope to do some testing next week. I'm slow at this sort of thing, having rushed it too often and suffered the problems with rushing. It's the slow down to speed up mode right now. As well, I've got some issues with my test equipment and platform that I'm not sure at this moment how I'll resolve. No comments on the output from this turbine, as it's not been tested. If you want to see interesting test results look on my website, where I've got letters from engineers who oversaw testing of my previous turbine.

I have used overhead projectors for enlarging, and it works, but I found you have to be very careful that the projector is 90deg to the wall, or your parts distort. I found that a set of 4 index squares around the edges helped with this. In the end though, getting them printed removes a possible source of error, and I don't have an overhead projector anymore. I also believe that the paper surfaced plywood is much stiffer than without.

Cp is a more precise term for efficiency. It stands for Coefficient of Power , and 1 would be 100% so 0.51 would be 51%. Efficiency can mean other things than this, so engineers prefer Cp as it’s specific

https://www.princessauto.com/en/detail/1-in-standard-duty-bearing-with-eccentric-locking-collar/A-p3870953e

Thanks for the great instructable BrittLiv I've found that old fashioned spring steel cabinet scrapers are a great alternative to sandpaper, especially if they are nice and sharp. Much faster than sanding, and they cut, rather than smear. Not the cheapest, but here's a link as an example. http://www.leevalley.com/us/wood/page.aspx?p=32639&cat=1,310,41069&ap=1

I'm glad to have instructable as a venue to share on, thank YOU :-) I hope you'll check out my newest instructable, https://www.instructables.com/id/Painted-Canvas-Over-Plywood-Vertical-Axis-Wind-Tur/

I've posted more images of working parts, and if you check out my other instructables you'll see more examples of working parts. Thanks for checking it out, and for commenting on what you'd like to see more, it's helpful to get your feedback, I'm sorry that I only saw this today.

Do you have any test results you can share on how much energy this generated? It seems to me that because the hub motor is not controlled for maximum power, it won't capture much.