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Apr 17, 2016, 10:43 PM
Classic jets rule
AIR SALLY's Avatar
Thread OP
Idea

171 mm fan...any interest?


Hello guys ,just putting a feeler out for a 171mm fan.it would use 15 dynamax blades on a @ 101mm hub/motor tube. The fan could produce up to 30-35 lbs of thrust.will use NEU motor,ceramic berings.and the motor hub/tube will be common with the center body as a heat sink. This fan would fit Byron sized Jets and bigger Jets that were designed for turbines. What do you think would any one be interested?
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Apr 17, 2016, 11:19 PM
Registered User
bri6672's Avatar
Problem is most turbines have pretty small intakes.... Not a lot of airframes could support that size fan and have 90% FSA or better...
Apr 18, 2016, 12:22 AM
Classic jets rule
AIR SALLY's Avatar
Thread OP
Well it's not as bad as you think as the rotor hub is 4" dia.
Apr 18, 2016, 04:33 AM
Banzai Institute
buckaroo's Avatar
Yea the hub would have to be around 4" using stock Dynamax blades. Roger do you think you would still get that much thrust with the reduced blade area? It would be nice to see a 6" or larger fan hit the market. From what I see the largest diameter motors we have to work with now are 56mm. If we could get 30lbs for around 150A of current that would be great for turbine size airframes. What you got in mind Roger?

Dean
Apr 18, 2016, 10:19 AM
Registered User
EDF Crazy's Avatar
Im interested,. What input power do you think it would need to make 30-35lb of thrust? do you think it could handle up to 50lb+ of thrust?

What do you think the fan would sell for?
Apr 18, 2016, 11:15 AM
Classic jets rule
AIR SALLY's Avatar
Thread OP
early calculations show the FSA to be @18-20 sq. inches.
still working on designing a motor with Steve Neu...so it wont be a off the shelf motor .....only thing off the shelf is the dynamax blades and sators, the blades will be custom machined so we can use 15 blades on the hub. with the larger hub the root of the blade is traveling much faster than a stock dynamax rotor so the stactic thrust will be improved . and with the 15 blades there really is not any loss of blade area.
we are trying to keep the amps as close to 150 amps but there are a lot of unknowns right now until we can get a fan built and tested.
so really just trying to see if there is enough interest out there to develop this size /cost of fan . it will be made in USA so not going to be cheap.
Apr 22, 2016, 11:30 PM
dare to be dull
bigjohn's Avatar
Interested for the eventual build of my Lassek A-10
Apr 24, 2016, 01:08 PM
Registered User
Angel RC Design's Avatar
Yes for the the Byron stuff that would be big plus
Apr 25, 2016, 11:57 AM
Classic jets rule
AIR SALLY's Avatar
Thread OP
I will keep you guys posted.....stay tuned
May 22, 2016, 09:04 AM
Classic jets rule
AIR SALLY's Avatar
Thread OP
OK guys I see some are interested......and there are some questions. There has been some headway made with power requirements. The voltage required ,and the size of the motor.like every thing else there are some trade offs for this kind of power.none of the parts and pieces are going to be off the self....which is going to drive the price. So I'll get the designer to pipe in with what info he now has.
May 22, 2016, 11:35 AM
Suspended Account
Most of you guys don't know who I am, or even my experience in the realm of EDF's Other than the facts which I can prove I started making ducted fan's in the 1980's when the first Dynamax's came out. Back then it was the AeroJet-46. It was a 4" fan with 10 blades, using K&B 7.5 or OS-46 VFDF. I made about 400. I also sold over 2000, AeroJet-25, AKA Midwest RK-20. Those were all glow engine days. Along with that I sold over 2000 Balsa kits, which were the F-4 and F-15. My company was and still is, SouthEast Model Products. In the late 90's when EDF's were just coming into the hobby, is when I got involved. I first started with the fan's available on the market, mainly from Europe. I looked to see what I could do with the Dynamax parts I still had. The glow ducted fan market basically died with the onslaught of turbines. I still had my complete wood and machine shop. I looked at the Dynamax blade and after doing some calculations, it looked like I could re-machine the blade down to put 9 blades in a re-designed rotor hub. To my knowledge nobody else has figured out how to hold the blade to re-cut the side angle. I have had some really good machinist ask me how I do it. My background isn't a machinist. I did take 2 years of machine shop in high school. I do have a BSEE degree, and spent most of my lile as a design engineer in the Aerospace industry. I have 3 patents in my name as the designer. Now back to the EDF market. The first design I did was a 90 mm fan using 9, Dynamax blades. I used a NUE motor. The rotor was cut down to 4" after it was assembled. Back then I was still running on NiCad's. I also built a Power Supply I still have that put out 5 to 50 V at 100 Amps. I used that for testing rather than battery's. When I first started to test the fan I had problems with balance of the rotor. The rotor actually flew off the motor. Back then I was using off the shelf prop adapters. I took the rotor to a guy I knew that had a Dynamic Balancer. It was out of balance, but not all that bad. I balanced it buy drilling a hole in the hub on the lite side and filling it with lead. I put in mor led than needed. Then adjusted the amount by re-balancing. It worked. A standard Dynamax rotor doesn't need any balancing today, as the blades are all so close you can see a difference. Because of the re-machining the blade angle, it does change the weight slightly. I can actually get very close to balancing by moving the blades around, but it takes a lot of time. It's easier just to balance the rotor, but there are several way to do it. I reinstalled the balanced rotor on the motor and started running again. I still had problems. but now with the collect. After trying several different collets, I really could not get a safe situation. That's when I did a totally new hub design. That design has been copied by Fred Baldwin, and again by Jim Drew. When I made the hub I also needed to have a longer shaft on the motor and enlarge the shaft diameter. After several motors made by Steve at Neu, I ended up with a 7 mm shaft with 2" coming out of the motor. It took over a year to come up with a design that worked. There were several other changes made, Originally the shroud was made from PVC pipe, that's the reason of the 4". I started to purchase the tooling for my machine shop to do more complicated machining. In a year I spent over $50,000. This is for tooling, not the machines, I already had a Mill and 2 lathes. Also during this time period I started making air retracts. When I finally got the first 90 mm EDF up and running with no problems, I could produce 10 lbs of thrust. As the market changed and the EDF field started to grow, I started to work an EDF that used 11 blades, so I didn't have to re-machine the blades. This is also when Fred Baldwin, and a little latter Jim Drew enter into the field. I had posted pic's on here of the EDF, and all the parts. Fred used the pic's to copy the hub. I still have a couple he sent me. His work good, but there about .001 out of tolerance. because of the way he machined them. All mine are .0002. That close enough to " Dead Nuts". I went back to 4" or 100 mm. Now more motors were becoming available, but there was still a problem with the shafts being to short and bearings that didn't last. That's when Mike Fallon, from SAPAC, contacted me and asked about my fans. He ask me if I was interested in making fans for a couple of new ARF's he was making. I did a design of a 105 mm EDF using the new Scorpion Outrunner. Nue mad a motor that would work, but was more than double in cost. My first issue was, no good way to install a heat sink, to get heat out of the motor. Right from the beginning all the EDF's I made had heat sink's as part of the center body. But this is an Outrunner. After redesigning the center body to mount the motor a couple of time. I got a design that work good. But still had bearing problems with the Scorpion motor. After about 10 flights the bearings need to be replaced. As far as I know, the problem still exist today. It's easy to fix. Just use a better bearing. Mike ordered 750 Units from me. He wanted 100 EDF's per shipping. I purchased enough material to make all the shrouds and center-body's. and about 5000 rotor blades for Tim Cook. and several thousand stator vanes. and a couple hundred spinners. I made the first 100 units in a couple of months. Mike sold all of them along with the kits he had. Them Mike got real sick. He had Lung Cancer., and was dying. He shut down the business and sold out everything. hat was the list time I made any EDF's in any quanity. As time went by and new moters started to appear, along with better battery's and ESC's, the conversion's of The orginal Dynamax started to grow. Jim Drew got into it big time. He bought 3 of the thrust stands I made. He cam out with a collet that worked OK, Later he copied my design. All the units I made for Mike use my hub design. Some of you may not believe that I did that design, but history doesn't lie. And I could care less. About 3 years ago I did a hub for a government agency that had 30 Dynamax blades. It was not going to be turned more than 10,000 rpm. That when I was able to use my fixtures to re-cut the side of the blades. About year and half I started work on a design to end up with a 6" Dynamax. Then, last year in April, I ended up having a operation to remove a 3 cm tumor. in my brain. then 2 months later I had 45 radiation treatments for Prostate Cancer, I apparently developed, from Agent Orange while in Vietnam. I asked How can I get that. I was on a Boomer Sub. I was told if I had 1 foot on the ground, I was covered. I'm now on 100% disability. The medical issues put the whole business on hold for over a year. Last month I stared to do the redesign of the Dynamax. I had the idea several years ago of making the centerbody the actual motor. Last month I ordered the design of the stator and rotor assembly for a standard Dynamax. I got several different KV design's delivered. I can post pic's. I also been talking to Steve, at Neu Motors about the motor for the 15 blade Dynamax. This is what we have come with. the cost oof just then motor parts ( Stator winding, and Rotor magnets ) is about $900. This is starting at a true 10Kw, not BS like I have seen a lot of on here. The max RPM is 30,000. My question, is the cost to make this EDF is not going to be Chinese prices. In fact I looked at having just the stator plates made in China are expensive. It's the cost of the tooling to stamp the plates. The capability of getting the power to run a fan this size is not an issue. its the cost of tooling to make the parts. Steve is using the largest stator plates he has available. Bottom line is this, This EDF can do the same amount of power as a turbine, but the cost is the same. To get past this point the tooling to make the stator winding poles is what need to change. The winding need to go to 3 phases to 6, No ECU is made to do that yet. Can be done. The commutation now need's optical feed back. As for the ESC, I looked at a Castle 160, I made a heat sink that can take it to just over 200 A continuous. A lot of thing need to change to go above 10 KW. The 15 blade rotor can go to about 35,000 RPM before the tips stall. Going to take a lot of power to get there. The capability to do it is there, the question is the cost. I have the parts from New being made this week. I'm just not sure how many of you guys are willing to spend that much money for a EDF unit. Buy this time I get it all done, were probably looking at a sale price of $2000 to $2500. Remember the old saying. Fast, Cheap or Quality, pick any two.
Last edited by SEMP001; May 22, 2016 at 12:00 PM.
May 22, 2016, 11:38 AM
Suspended Account
Oh, If you see any mistakes in grammar, Please excuse them. The word processor on here isn't smart enough to fix them.
May 22, 2016, 12:42 PM
Pro Hoarder
turbonut's Avatar
Man that is a long sentence..lol
Latest blog entry: In flight
May 22, 2016, 01:56 PM
Suspended Account
Quote:
Originally Posted by turbonut
Man that is a long sentence..lol
I didn't want to leave a lot of questions.
May 22, 2016, 04:45 PM
The 6 P principle works for me
elecfryer's Avatar
How the heXX do I know what I don't know? WOW, talk about undiscovered history! Hope you continue to feel better. Certainly this is a bit outside of my budget however, I continue to be amazed at how the EDF envelope continues to be expanded! Hats off to you and good luck with your awesome project!

Michael


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