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Aug 06, 2017, 10:43 PM
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9-15kw/23-30lb "CAT 8" Dynamax


UPDATE-June 2018

For the latest information and prices, please visit WWW.EDFDYNAMAX.COM

See below for latest test videos with thrust all the way up to 34lbs.

——————————————————————

Finally have some time to start a new thread on the aforementioned topic and hopefully 15kw is enough for the moderators to keep it in this forum. The cat is already out of the bag but I'd like to provide some details on where I plan to take this fan.

This thread will cover two primary fans, which are intended for medium sized turbine conversions to the larger jets. Lee has some interesting plans after the hotspot but I will let him share that idea when he is ready. The voltage range in mind here is 16s up to 22s or even up to 23s if the ESC will arm since voltage will drop to acceptable levels under load almost immediately after throttling up.

What sets this thread apart from the V1 kit is the addition of a stainless steel retaining ring around the front of each blade along with some other CNC parts needed to mate TP motors with 8-10mm shafts. I decided to go this route after experiencing a failure on a rotor at 36k RPM. Fortunately, this failure showed where the rotor needed additional strength and thus, the retainer ring was born.

Most of you have already seen videos of the 18s fan (34k/24lb/10kw). Without having access to a lab that would allow me pull apart a rotor and determine the exact amount of force being applied at the point of failure, I felt anything operating in that power band and at that RPM deserves an additional safety margin. So, that's what I tested first and believe that fan is now ready for primetime. The 18s fan is shown below with a 3D printed gold colored spinner. This fan has produced 24lbs of thrust on the bench using 8000mah Nano tech batteries. That test video should be up sometime this week. This fan is a perfect solution for converted aircraft capable to holding 3x8000mah Li-Po's. I believe the installed thrust will be around 22lbs with a 15" duct behind the fan. Exact efflux is TBD but I have seen numbers as high as 280mph based on eagle tree data. I would like to double check this with another device before I call it good.

The ultimate version of the Dynamax though is the 15kw monster...that's 20 HP for the non EDF crowd. Some of you may question the desire or need to have such a high powered 128mm fan. I will let each individual answer that question for themselves. My perspective is that the Dynamax has been a very linear performer from 10lbs all the way up to nearly 30lbs. This was also confirmed by the fact that we are seeing 29.7lbs of thrust at just about exactly 15kw. Based on previously collected data, the power to thrust equation had shown it would take just this much power to hit the desired thrust value. So, performance is linear even at this insane power level. This fan is intended for A/C like the hotspot which were meant to fly at the 30lb AUW range. This fan is ideal for those looking for a nearly 1:1 t/w ratio...or exceeding it depending on the batteries used.

Another question that is raised at this level of power is regarding the batteries. The reason why I tested the 30lb/15kw fan on 16ah batteries was to simulate what someone would get out of some quality 10000mah batteries that are capable of 20-25c. This is not an unrealistic expectation with the batteries we have available on the market today. The ideal setup is 2x5s and 2x6s packs to make up the 22s needed. On top of this, battery technology will continue to improve immensely and i'm sure the day is coming when we will see significantly lighter batteries with more capacity. Of course, capacity can be reduced for higher C rated batteries but i'm not a fan of that. I prefer to keep it easy on my battery packs.

I will end this here for now with some pictures attached. Hopefully we can keep this discussion civil as there is no need for it to go any other direction.

“Cat 8+” 30-34lb fan on 22s (experimental only)
"Cat 8" Dynamax EDF (30-34lbs Thrust) w/TP-5870-500kv on 22s/6ah 65C Turnigy Graphene Lipo's (2 min 59 sec)


“Cat 8” 27-32lb fan on 21s (experimental only)
"Cat 8" Dynamax EDF (28-32lbs Thrust) w/TP-5870-500kv on 21s/6ah 65C Turnigy Graphene Lipo's (6 min 29 sec)


“Cat 6” 26-30lb fan on 20s (available for sale as a plug and play system)
"Cat 6" Dynamax EDF w/TP-5870-530kv on 20s/6ah 65C Turnigy Graphene Lipo's (5 min 2 sec)


“Cat 4” 22-26lb fan on 18s (available for sale as a plug and play system)
"Cat 4" Dynamax EDF w/TP-5870-530kv on 18s/6ah 65C Turnigy Graphene Lipo's (5 min 17 sec)
Last edited by Par_18; Jun 02, 2018 at 10:11 AM.
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Aug 06, 2017, 11:13 PM
Lee Liddle
Knife Liddle's Avatar
Those are some good looking fans. Subbed in...
Aug 07, 2017, 07:36 AM
3d and EDF, some scale
MustangAce17's Avatar
Man, I can just imagine a K1 Eurofighter with this set up, what is the projected cost versus a turbine?
Aug 07, 2017, 08:32 AM
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Originally Posted by MustangAce17
Man, I can just imagine a K1 Eurofighter with this set up, what is the projected cost versus a turbine?
You will see something like that in the near future....

For the 30lb/15kw setup, Cost will be between $1000-1200 with ESC. That price range exists to account for any unknown that may show themselves during testing like the need for better bearings and such.

The 18s setup will be around $850 with ESC.
Last edited by Par_18; Aug 07, 2017 at 10:31 AM.
Aug 07, 2017, 08:37 AM
3d and EDF, some scale
MustangAce17's Avatar
Nice! So a fraction of a turbine cost and close to the same performance, been waiting to see this happen, keep the awesomeness coming
Aug 07, 2017, 09:04 AM
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Aug 07, 2017, 10:09 AM
Registered User
"For the 30kw setup, Cost will be between $1000-1200 with ESC"

"The reason why I tested the 30kw fan on 16ah batteries"

Par is this 30 LB or are your working on a 40 Horsepower Fan?
Aug 07, 2017, 10:23 AM
Registered User
Par, you have done amazing work here. I've never seen anyone pursue something like this as relentlessly as you have.
Since this is a new thread, how about some discussion regarding inlet area (FSA) needed and exhaust diameter size so we can see which airplanes this fan can be used in?
Maybe even suggest some specific airplanes such as Avonds F-15, Skymaster ARF's, etc.?
Jim
Aug 07, 2017, 10:29 AM
Lee Liddle
Knife Liddle's Avatar
Quote:
Originally Posted by Lear45
Par, you have done amazing work here. I've never seen anyone pursue something like this as relentlessly as you have.
Since this is a new thread, how about some discussion regarding inlet area (FSA) needed and exhaust diameter size so we can see which airplanes this fan can be used in?
Maybe even suggest some specific airplanes such as Avonds F-15, Skymaster ARF's, etc.?
Jim
Airframe discussion is a good idea. FSA on the Dynamax is fixed, and it's well known for it's ability to handle choking down the exhaust. So let's look at airframes.
Aug 07, 2017, 10:30 AM
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Thread OP
Quote:
Originally Posted by Air Head
"For the 30kw setup, Cost will be between $1000-1200 with ESC"

"The reason why I tested the 30kw fan on 16ah batteries"

Par is this 30 LB or are your working on a 40 Horsepower Fan?
No sir. I meant to say 30lbs/15kw. Good catch!
Aug 07, 2017, 10:33 AM
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Quote:
Originally Posted by Knife Liddle
Airframe discussion is a good idea. FSA on the Dynamax is fixed, and it's well known for it's ability to handle choking down the exhaust. So let's look at airframes.
Good idea and that is where I need help from all of you because not only am I tapped out of funds for new airplanes but I won't have any time for at least the next 6 months to build one. Lee is take the initial stab with the hot spot and I have a couple of folks who may help as well.
Aug 17, 2017, 02:01 AM
HAL... Open the damn doors!
jfetter's Avatar
Nice to see someone providing numbers, always appreciated when testing! I do have a concern about the power required, seems 15kW is very high given the JetFan 130 is charted @ 29.77lbs on 10.6kW, IMO this would seem to be a bad choice of motor (a lot of wasted heat must be costing a ton of Watts as the unloaded RPM @ 530kV x 22S is just shy of 49K RPM, way too high!). IMO 22S should be paired with a motor around 400kV, maybe 375'ish...

Jack
Last edited by jfetter; Aug 17, 2017 at 02:06 AM.
Aug 17, 2017, 03:21 AM
Lee Liddle
Knife Liddle's Avatar
Hi Jack, Par is in the middle of a move from Virginia to South Texas so he may be preoccupied with that for several weeks.

I have a couple of theories about why it appears that the Dynamax requires a lot more power to reach 30lbs of thrust compared to the Jet Fan and also the Scheubler 130.
1) the 2 European fans are both 3mm larger in diameter. I'll have to do the math, but on a 5" fan adding 3mm starts to become a significant amount of area.
2) the 2 European fans also incorporate a more cone shaped hub which also increases the effective swept area of the fan's.
1&2) both of these facts combine to cause a disparity in FSA between the two European fans and the Dynamax. IMO, or guesstimate is that we are comparing a 127mm fan to what are in effect fans that are equivalent to 133mm fans.

We all know that a larger fan will produce more thrust at the same power level than a smaller fan. However, it does so at a lower efflux speed. So you have different areas of performance. The laws of physics will tell you that there's no free lunch. If they use less power, they are doing less work, and in this case, it will only show up when efflux speed is measured.

3) Neither Scheubler nor JF are giving us (much less showing us) all of the real time numbers. They are only offering a "snap shot" of a spot on their graph. But it's not even a photograph. It's more like a pencil drawing of the photograph (their chart) where the actual numbers are kind of fuzzy and open to interpretation.

My conclusion is, that until they supply real time data, and we can get some efflux speed numbers, then a direct comparison of the 130mm fans to the 127mm fan is not an accurate picture at all. It's more like comparing an 80mm to a 70mm.......pointless unless you compare All of the numbers.
Aug 17, 2017, 08:23 AM
HAL... Open the damn doors!
jfetter's Avatar
I think you might be overthinking this. Running @ WOT, this fan/motor combination will never spin @ anything close to 49K RPM, it's just not a viable pairing IMO. Take the BVM 5612 VioFan @ 690kV running on the standard 12S, that's a tad under 35K RPM unloaded, perfect pairing IMO. You just can't pair any fan that should spin around 30K RPM loaded with a motor that is trying to spin @ 50K RPM (530kV x 22S). Am I crazy?

Jack
Aug 17, 2017, 09:02 AM
Lee Liddle
Knife Liddle's Avatar
No Jack, you're not crazy, but I'm not over thinking it either. It's much more involved than just multiplying the unloaded kv X number of cells X 4.2.

First, the loaded voltage should be figured at about 3.6. No cells hold more than that for more than 30sec or so. Then, if you can turn 90% of what your unloaded kv is, then you have only 10% losses. That is excellent performance.

For Par's 22s fan at 3.7v per cell X 22s X 530 X .9 = 38.8k. Very close to what he is measuring. So, when you can run a fan at 39k, 30lbs, 15kw and only see 10% losses, that's a well balanced system. Is it super efficient? No. Is it super powerful and operating within it's good power band? Yes it is.

The reason that the 130mm fans mentioned above can possibly produce 30lbs at 11-12kw (still needs to be shown real time before I accept it) is that they are larger fans and larger fans produce more thrust at the same power level. However, I still need to see it real time before I quote as fact.

In this day and age, a chart or a quick video just showing thrust is proof of nothing and shouldn't be compared to the comprehensive data that Par is providing us.

What I'm seeing is guys taking some numbers off a chart, or off a video showing incomplete data. Then they are comparing to Par's fully documented, real time, streaming data. They pick a point on Par's data then say "well, this other fan does this or that better or higher or more efficiently. "

All I'm saying to them is "show me a video that proves it. Don't show me a chart or quote some numbers from an ad or a website. Show me proof. Then, if it's justified, make the comparison.

So far there is nothing to compare it to that covers all of the bases with video proof, just miscellaneous 30 second clips showing thrust or a chart.
Last edited by Knife Liddle; Aug 17, 2017 at 11:25 AM.


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