Well, my new wind grabbers are installed and are the quietest blades I've ever heard. These blades are the 5th set over a 30 year period of wind generating. Anyway, quiet as they are, I need them to turn much faster at lower wind speeds. I realize that the blades that came with the Whisper were designed for that unit. Unfortunately that style isn't made anymore. I bought it in 1991. Has anyone tried modifying a set of wind grabbers to make them spin faster? I've looked at different designs and was considering slimming the base of each blade narrower and possibly lessening the turbulence they create. I'd really like some advice from anyone that might know if it would work. I sure love watching them turn though,and did I mention they were quiet, to bad they only start producing amps at over 30 mph. Should have had them up when it was blowing 60 mph.
I found this. If it is correct. Wind grabbers are way too small for this one. - The Whisper 1000 was a 2 blade, ~9ft dia. machine, nominally 1000 watts. It was available from World Power Technologies back in the late 90's (at least).
Tom, thanks for getting back to me. Ya, I know the wind grabbers are smaller, but there's 3 blades. I didn't realize 3 blades are slower than 2 blades. I don't have much choice though. I might have to do some experimenting on the wind grabbers myself. The new Whisper blades won't fit on my old unit and to change wind generators and voltages from 32 to 24 is cost prohibitive, at lest for now :x . I do like the aircraft aluminum construction of the wind grabbers. Maybe someone else out there has done some modifications to blades.
I might have found a way for my dilemma of the shorter blades, make them longer! :idea: I'm going to add extensions from the hub, probably 3/16" or 1/4" aluminum, the same width as the three fingers from the hub to make up the difference in diameter of the original 9' blades. Hope it works. I'll post the results in case anyone might be interested.
Barry, Have you considered that there might be something wrong with your wind turbine (bearings, electrical connections, slip ring, etc.). While there is no doubt that the windgrabbers will make less power than the original 9 foot blades, I find it hard to believe that you are not making amps until 30 mph wind unless there is something else wrong with your wind turbine or electrical connections. I do think extending the blades could work well for you but I also do think some trouble shooting is in order to make sure you don't have any other problems.
WindyGuru, The Whisper checks out good and it's actually charging up to 640 watts now. Mind you, it's blowing over 40 mph, gusting up to 50 mph. The furling is working great too. I can now see how longer blades would help. My safest option is to have another hub built extending 14" more. Please forgive me for saying this again, but I've never heard quieter blades, there's been many nights I have not slept well from the old Whisper blades howling, especially while furling. ( tried to send a pic but says: Sorry, the board attachment quota has been reached. ) I don't know what that means?
I have gotten mine to spin faster. Probable not recommended by most but it does not take much. If you lay the blade down. You will see that the wider part of the blade is turned up more. I marked mine at 1/3 width and used a rubber mallet to flatten the curve out enough that the blade touches on both sides all the way down. Put something under the blade edge while doing this so it can slide. Also stay away from the middle of the blade. It will crease and you will have to find a big pipe to form it around to get it out. So basically what I did was make the curve the same all the way down. I still do not believe it but waiting for a good windy day to confirm this. Before 21 MPH 200 Watts ***NOW*** 21 MPH 321 Watts. Must be spinning faster.
Hey, thanks Tom, I might give it a try. When you say 1/3 width, I'm not sure I understand correctly. Is that 1/3 from the wider end toward the tip and hammer at that place?
Yes about one third up from the widest part of the blade. On mine when I got it done it touches all the way around when I laid them down. http://www.windynation.com/community/threads/flying-as-of-6-30-2010.197/page-3 This is where the pictures are. I am still waiting for some good wind to post some more info on how they worked out.
You can also look at this and put some numbers in to see what you can come up with. http://www.windandwet.com/windturbine/power_calc/index.php
The blades are starting up around 4-5 mph and I have seen higher output out of the turbine so far. Been up to 300-400 more often. I am now working on getting the other turbine ready. For this one I have extended the 30 inch blades out to 8 ft and will be trying it out soon and will be comparing the 2 sets.
HI TOM T I've had to order another set of 35" Windgrabbers as the first ones developed a flex crack in each of the three blades at the first bolt. I had suggested an idea that might help, before I ordered the new set. Well, they came with no new improvements, so I made my own. as you can see from the photos, it was quite easy to do. They have been up now for a month (with the improvements) and have gone through some hellish winds. Some gusts were upwards of 57 to 60 mph for three or four days in the Strait of Georgia between Vancouver Isl. and the mainland. I took them down on a calm day and they look good and were still quiet. I think the blades are great and I get 750 watts out of my 1000 watt Whisper. Here's a few photos and the improvements:
Looking good hope the improvements work out for you in the long run. Mine have been up for over a year with wind gusts only to 40-50 mph and I have had no problems yet. I check them every time I go up on the roof. Which has been every few months.
The best way to avoid metal fatigue on all WindyNation blades is to have a good furling design in place. The blades should begin to furl out of the wind at ~28 mph and should be 100% furled (a 90 degree turn out of the wind) by 34-35 mph wind. Barry, if you have the blades mounted on a 1000 Watt Whisper, it is probably furling way later than ~28 mph. This is because the original Whisper blades that came with the wind turbine were longer and heavier than the Wind Grabbers. The furling for the Whisper was optimized using the original blades. Once you put shorter and much lighter WindGrabber blades on the Whisper, the Whisper will begin to furl at a higher wind speed which is not good for the blades. To counteract this, you could shorten the length or the weight of the tail. Both of these things will help the Whisper furl at a lower wind speed.
Thank you very much windyguru. Why didn't I think of weighing out the difference. I don't have an opportunity to weigh the WindyNation's hub, since it's on the Whisper right now, I'm guessing somewhere around 2 lbs. The Whisper blades plus the hub and bolts weigh in at 9 lbs. 4 oz. And the WindyNation's blades and bolts weigh 5 lbs. 4 oz. + 2 lbs(approx.hub) = 7 lbs. 4 oz. Looks like I've got around 2 lbs. difference. Has anyone got the exact weight of the WindyNation's hub? Then I'll have to lose a couple of pounds from the tail. Hope I get the same wattage out of the Whisper. And Tom T, thanks too! Does your windgenny turn out of the wind at 28 mph with your longer and flatter blades ?
With the longer tail and weight I put on it it turns about 45 degrees out of the wind total. That works to keep power production going up with the wind.
