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Jan 28, 2018, 09:05 PM
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Just did some more 12s tests including an extended run and some consumption tests, also hooked up the Emeter2's RPM sensor to the new ESC.

Interesting that I pulled 3100mah from the 12s10Ah pack set during final balancing and on recharge for the full run the Hyperion charger and VISTA CD3 charger both showed 1550mah back into each 5Ah pack +/- a few mah. So either they are all badly out of calibration together, or the Emeter's amps and volts reading is pretty accurate.
Video to come.
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Jan 29, 2018, 12:28 AM
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Here is the short run on 12s, 6100 watts for 8.9kg thrust (19.5lb)

Extreme RC presents Ramtec 11 Blade 127mm Electric Ducted Fan! (1 min 26 sec)


And here is a longer run for approx. a minute, batteries hold their voltage well and we are seeing 8.5kg sustained on only 12s and 5700 watts, nothing to sneeze at!

Extreme RC presents Ramtec 11 Blade 127mm EDF extended run (3 min 2 sec)
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Jan 29, 2018, 07:05 AM
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Quote:
Originally Posted by EDF Crazy
As the Ramtec is a larger fsa fan I then compared it to the Jetfan 130, Ramtec needed 7555w to produce 22lb of thrust, the Jetfan 130 got 23.26lb of thrust at 6971w which is 1.51g/w . A fair bit more thrust on less watts for the Jetfan. So there is more to ponder then what you have shown here.
I am going to revist your comments above as you seem intent on finding one fan to be smaller than the other...The Ramtec rotor is 125mm diameter, Tony machines them to this size, same as the Dynamax. The 127mm is the shroud ID, pretty sure the Dynamax is the same.

Now I went and had a look at the JF130 charts, I found the TFL56104 figures I am guessing you are pertaining to, 6971w on 14 cells for 22lb thrust which is identical to the figures I was comparing, not 23.26lb you stated, you jumped a line when reading thrust. Now looking closer at this comparison of yours I find the 56104 motor weighs in at 1100 grams! That's more than my entire fan weighs.

So knowing the Par Dynamax carries a TP5670 at 962 grams then the JF130 would be an excellent comparison to the PAR fan, and trumps it by a large margin, over 1400w less, with exactly the same amp draw on 4 cells less for the same thrust, and likely knowing Rainers construction the JF130 combo is lighter overall.

You cannot compare the JF130 to the Ramtec with a 500 gram HET motor in it, they are completely different beasts.
I have great respect for Rainer and sell a lot of his fans, the JF130 is not really something you would purchase to simply run at 22lb, its potential is much much more than that.
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Jan 29, 2018, 07:42 AM
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EDF Crazy's Avatar
Quote:
Originally Posted by Extreme_RC
I am going to revist your comments above as you seem intent on finding one fan to be smaller than the other...The Ramtec rotor is 125mm diameter, Tony machines them to this size, same as the Dynamax. The 127mm is the shroud ID, pretty sure the Dynamax is the same.
Its what ive heard so many times, so im hoping to get some clarification on this.

Quote:
Originally Posted by Extreme_RC
Now I went and had a look at the JF130 charts, I found the TFL56104 figures I am guessing you are pertaining to, 6971w on 14 cells for 22lb thrust which is identical to the figures I was comparing, not 23.26lb you stated, you jumped a line when reading thrust. .
Below is where i got my data from showing 23.26lb thrust on 6971W. (Circled In Red)
Last edited by EDF Crazy; Jan 29, 2018 at 07:54 AM.
Jan 29, 2018, 07:56 AM
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EDF Crazy's Avatar
Quote:
Originally Posted by Extreme_RC
So knowing the Par Dynamax carries a TP5670 at 962 grams then the JF130 would be an excellent comparison to the PAR fan, and trumps it by a large margin, over 1400w less, with exactly the same amp draw on 4 cells less for the same thrust, and likely knowing Rainers construction the JF130 combo is lighter overall.
Hopefully we will see soon when you use larger motors what the Ramtec can really do as a comparison to the other two also.

There is also I think alot more going on here than we realise with the eflux speeds not being factored into any of this. Eflux speeds are a huge factor to inflight efficiency also.
I have two planes that need fans and want to see the full picture before choosing which to use for each, One needs more thrust and the other more speed. I am however very interested in setups for both projects that are at 18s @120A -140A for them.
Jan 29, 2018, 05:56 PM
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That chart may have been incorrect as the current one shows a lot more tests and different figures (see below).

The Ramtec has the speed in the air, always has, check out the video of the JET TENG Viperjet running my CNC Alloy Ramtec on 14s, 170+mph in a huge draggy model.

Tony designed the rotor blades to suit the OS91, his rotor brought the RPM of the OS91 down around 1200rpm and made it reliable, also peaked out in a dive at 200mph or more, I cant recall the exact speed he said they got from the Spectre. Don't forget the original Ramtec was 9 blades.

The dynamax was never really as suitable for the OS91, its never really had any changes since TC paid for the design (done by some guy at GE wasn't it?).

Tony on the other hand designed the ramtec in house, owning an engineering CNC machine shop and injection molding gear means he is fully capable of redesigning anything which is why he has been able to pander to my constant requests as well as his own keenness to make the Ramtec electric. He changed the blade mold and filled the root void so he could machine the bases down more and make me multiblade rotors. I have 12B rotors as well as the regular 11B we use, in fact I am going to build the fan for my MIG15 this week and will do some tests on that with the 12B rotor. I also want a 10B rotor to test as I think it could be a nice configuration for speed and thrust.

Changes will take time however, there is little money in large fans and Tony like all of us needs to eat so he does paying work first and foremost, spare time gets allocated to things like the Ramtec these days.
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Jan 29, 2018, 06:15 PM
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Quote:
Originally Posted by Extreme_RC
The Ramtec has the speed in the air, always has, check out the video of the JET TENG Viperjet running my CNC Alloy Ramtec on 14s, 170+mph in a huge draggy model.
.
What? A JTM 1.7m (72in) wingspan EDF is huge???? This is plane designed for 110 to 127mm fans...it's exactly the size jet optimized for 110-127mm fans. You wouldn't want any smaller. It's only 5 inches longer than a Starfire 2...which is about as small an airframe that you can wrap around a 5 inch fan.

And draggy? The JTM Viper is about as clean as it gets. It does not have oversized intakes (maybe on the small side for 127mm) and is a very clean airframe with sealed skin hinges and thin airfoil sections, and full year doors. The high aspect ratio wing will give the lift you need to haul big batteries with low induced drag. It's about as close to an EDF hotliner as you get...certainly for a scale airframe that can accept regular brick packs (no saddle packs please)

Be nice to the JTM jets, they are about the only game in town trying to make jets for the fans you push here. The main reason the market is small for these fans is the distinct lack of properly designed 110 to 130mm EDF kits and ARFs. Somebody who makes fans should also be investing in making kits as well. If for no other reason than to sell PNP combo packages...that are somewhat cheaper than BVM stuff. I know its easy for me to say, but it seems weird that someone has not teamed with JTM to sell PNP fan/plane combos. seems like a mutually beneficially situation to me?

As far as the Ramtec being faster in the air, this is an artifact of the ICDF days that in no way correlates to electric propulsion. A dynamic can produce the same Efflux , it just requires a higher RPM to do so...which was beyond the OS91 power and safe RPM. The Ramtec capitalized on this by being designed with a higher RPM loading, sacrificing low end thrust for optimized dynamic thrust at the peak of the OS91 hp/torque band. An electric motor has 100% torque at any RPM...you just have to chose the correct KV for the desired fan RPM under load.
Last edited by Air-Jon; Jan 29, 2018 at 06:40 PM.
Jan 29, 2018, 06:36 PM
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I pulled out some boxes to do some measurements for you, I am sure they will be appreciated by others as well.

I have both 11 and 12 blade Ramtec rotors on hand, as well as my last Dynamax rotor with the old TJ hub. I have measured everything, list as follows:

Ramtec hub: 57.05mm
Dynamax hub: 58.15mm
Ramtec rotor dia: 125mm
Dynamax rotor dia: 125.3mm
Ramtec housing ID: 126.5mm
Dynamax housing ID: 127mm
Ramtec blade root height: 33.35mm
Dynamax blade root height: 30.45mm
Ramtec blade tip width: 28mm
Dynamax blade tip width: 29mm

Punching hub & rotor dia numbers into FSA calculator I get:
Ramtec 100% FSA: 9715.609
Dynamax 100% FSA: 9675.385

Putting in hub and shroud ID I get:
Ramtec 100% FSA: 10011.90
Dynamax 100% FSA 10011.92

Ramtec has 6 larger stators, dynamax has 16? smaller stators, cant tell you the area the stators take up! What is the drag from 6 vs 16 stators though?

Tony recommends 100mm for the exhaust, around 80% FSA.
Going down to 95.25mm (3.75") on the Dynamax means around 73% FSA.

Weight of the current Ramtec rotor complete ready to install is 223 grams. Dynamax in the TJ hub is 170 grams, but this is only really good for 12s with a 680Kv motor scenario, you wouldn't want to run this hub much harder. I am sure with a solid hub the Dyna rotor is as heavy of not more heavy than the Ramtec.
Last edited by Extreme_RC; Jan 29, 2018 at 06:59 PM. Reason: forgot rotor diameter!
Jan 29, 2018, 06:44 PM
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Quote:
Originally Posted by Air-Jon
What? A JTM 1.7m (72in) wingspan EDF is huge???? This is plane designed for 110 to 127mm fans...it's exactly the size jet optimized for 110-127mm fans. You wouldn't want any smaller. It's only 5 inches longer than a Starfire 2...which is about as small an airframe that you can wrap around a 5 inch fan.
Be nice to the JTM jets, they are about the only game in town trying to make jets for the fans you push here.
The XXX Jet does the same speed on 12s with the same fan, the Viper is more draggy in comparison. My comments were tongue in cheek, dry humor doesn't come across well in a forum huh
The JTM was never originally designed for 110mm fans, it was designed for the Euro 120 market, and they made adapter sleeves to fit the 127mm as well. I was selling the very first JTM jets released and have been nice to Andy ever since the 90mm Hawk first came out thank you very much.
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Jan 29, 2018, 06:46 PM
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Those are beautiful fans, and the selectable blade number is a really nice feature for matching motor torque. I personally much prefer the sound of the Ramtec to Dynamax, which are almost too quiet for me.

The only thing holding fan back, is lack proper airframes that are PNP for the fan.
Jan 29, 2018, 06:52 PM
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Quote:
Originally Posted by Extreme_RC
I was selling the very first JTM jets released and have been nice to Andy ever since the 90mm Hawk first came out thank you very much.
So what is the barrier to selling Ramtec ready JTM airframes? I think having the mounts and ducting set up for drop in Ramtec would be a selling point? If you sold a RXR Viper or XXX for 2500 AUD, I think there would be a market for that...
Jan 29, 2018, 07:11 PM
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There are logistic issues to doing that here unfortunately. Andy did the 127mm adapter tube at my request, and changing mount width would not be much of an issue, but the only way to make the kits competitive here is to ship them direct to the customer, shipping within Australia for this size of box is crazy $$$, a lot more than the EMS cost from China to anywhere in OZ. So I cannot put the fan into the box and then send it all out together at any sort of affordable price here.

I already list the kits at AUD$2000 including local taxes and they are ordered with whatever adapter is required. Its actually around $1800 once tax is paid which is JTM's RRP equivalent but my price includes shipping anywhere in OZ from JTM which is an AUD$200 hit to me.
I do sell kits and fans, send the fans out locally with kit shipped direct. But the market here is very small, 22+ million people here, the only ones who can fly these things are MAAA club members of which there are not that many! Take Germany and France as a comparison, over 130 million people between them, and we all know the population in the US.

Best scenario is for me to be able to send fans to customers around the world who have purchased a Ramtec ready JTM, its something I have spoken to him about and will revisit as really the only thing that hasn't been done is the mount width optimized.
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Jan 29, 2018, 07:46 PM
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I see. I think the drop ship option works fine too. If the install kit was included for the Ramtec and it all bolts together easily, It does not matter too much where the boxes come from.

I think having a proven plane/fan system(s) and a nice website with videos of the build and jets flying...and you would have something different. If it takes off..I would hope JTM would offer more airframe options.
Jan 29, 2018, 08:45 PM
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I used to run a Ramtec 9 blade with a Neu 1917 1Y on 14S in a XXX. Setup pulled 135A and that was a quick jet. It was fairly quiet up until about 2/3 power, but had a distinct sound at full power, the 11B rotor is more civilized as far as sound goes. It was a tight fit in the plane, and running 14S 6500 it was on the heavy side too, think it was 8.9kg RTF. I have a 95mm ID burner ring in the XXX, so that's also the thrust tube diameter I could run, it did not bother the Ramtec too much as I had good vertical performance as well as speed.
Jan 29, 2018, 11:05 PM
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The fans are a tight fit, no denying that! The XXX would have been bloody quick on 14s, don't think I have ever seen one on more than 12, did you have any video of it Arngeir?
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