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Old Nov 03, 2013, 04:50 AM
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Ramtec's Avatar
Melton Australia
Joined Mar 2009
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New Product
Ramtec has 12 blades

I have just returned from flying my Sabre testing a 12 blade Ramtec.
Results are very promising.
Performance is the same as the 9 blade rotor due to the same pitch on the blades.
The Ramtec 12 blade rotor has no whine at all, in fact it is absolutely silent.
It is as if the Sabre was an unpowered glider ! Sorry no video.
In the next few weeks I will make a 10 blade and 11 blade rotor to try to get some woosh sound and a slight whine.
To give you an idea of the harsh sound of the 9 blade Ramtec here is a video from ArngeirB

Falcon 120 with Ramtec EDF unit. Motor is Neu 1917 1Y running on 12S 6500mAh Hyperion 35C batteries, esc used is a Turnigy Dlux 160HV

Falcon 120 Ramtec EDF (5 min 2 sec)
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Last edited by Ramtec; Nov 03, 2013 at 04:54 AM. Reason: Adding more info
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Old Nov 03, 2013, 09:40 AM
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Arngeir Blakseth's Avatar
Molde, Norway
Joined Jan 2001
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Interesting news, the Ramted did indeed have a very loud whine in my Falcon 120, it is not nearly as bad in a fully ducted plane though, but it is still there. I have been doing fan tests in my xXx the last couple of days (finally close to amaiden flight) and I noticed the fan making much less noise than I had been used to. And this even running on 14S now, I have added a 2S booster pack to the Hyperion 12S setup I used in the Falcon.
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Old Nov 03, 2013, 12:22 PM
deltas are cool
AIR SALLY's Avatar
Tehachapi ,CA.
Joined Apr 2006
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cool news ...what was the amp draw? and what kv motor are you using .
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Old Nov 03, 2013, 04:38 PM
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Melton Australia
Joined Mar 2009
126 Posts
Maximum amp draw was 132 Amps.
Motor is a HET 800-73-590 KV
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Old Nov 04, 2013, 02:55 AM
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Russian Federation, Murmanskaya oblast, Kirovsk
Joined Nov 2011
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Photo?
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Old Nov 04, 2013, 09:55 AM
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Fontana, California, United States
Joined Jul 2004
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Nice Tony!
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Old Nov 05, 2013, 07:01 PM
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Ramtec's Avatar
Melton Australia
Joined Mar 2009
126 Posts
Photos

Standard Ramtec Rotor 9 blades above, 12 blades lower
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Old Nov 05, 2013, 09:13 PM
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Fontana, California, United States
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Hi Tony, did this change the rotor load? Is it drawing more amps?
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Old Nov 05, 2013, 11:17 PM
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Melton Australia
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Quote:
Originally Posted by rvincent View Post
Hi Tony, did this change the rotor load? Is it drawing more amps?
Hi Bob,
Both the 9 blade rotor and the 12 blade rotor were driven by a HET 800-73-590 kV motor
Quite a mild set-up compared to the Scorpion motor at 650kV.
Static testing of the 12 blade rotor was done on fresh 10,000 mAh 30c packs.
Testing on the 9 blade rotor was done using less efficient 5500 mAh batteries.
Results of the 12 blade rotor with better batteries are:-
116.8 Amps 44.98 Volts 5254 Watts
23010 rpm 7.65 kg thrust on Air Sally's intake lip
results courtesy of Mark at Extreme RC ( I wanted to get independent results)
Conclusion:-
The power went up by 461 watts and the rpm went up by 660 rpm. (due to better batteries)
However thrust was the same as the 9 blade rotor @7.7 kg so it seems that the efficiency is lower by 8.8 %
I need to have more back to back testing done on the 9 and 12 blade rotor.
I also want to make a 10 blade and 11 blade rotor to see if I get a better overall result.
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Last edited by Ramtec; Nov 06, 2013 at 02:12 AM. Reason: Motor Specs Added
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Old Nov 06, 2013, 07:37 PM
deltas are cool
AIR SALLY's Avatar
Tehachapi ,CA.
Joined Apr 2006
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i think 11 might be better ...im sure if the pitch was less that might help too. interesting info thanks for posting. i wonder if the blades are too close together ...maybe blanking them selves???
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Old Nov 06, 2013, 11:11 PM
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Melton Australia
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Quote:
Originally Posted by AIR SALLY View Post
i think 11 might be better ...im sure if the pitch was less that might help too. interesting info thanks for posting. i wonder if the blades are too close together ...maybe blanking them selves???
Thanks Roger for the input.
I don't think that the pitch is too high but rather the 12 blade fan is too solid.
2 factors that need to be considered are:-
1)The 12 blades should have given a higher static thrust than the 9 blade rotor at the same rpm especially if the pitch was too high to begin with.
2)Note that the speed of the 12 blade rotor was measured 660 rpm higher due to better batteries. This too should have increased the static thrust since one might assume more air displacement at higher rpm.
So I conclude that there is blanking of the blades.
I will make an 11 blade rotor next week.
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Last edited by Ramtec; Nov 06, 2013 at 11:27 PM.
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Old Nov 06, 2013, 11:30 PM
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Extreme_RC's Avatar
Australia
Joined Mar 2006
11,542 Posts
My original idea was to make it 11 blade, so once Tony has done an 11 blade assembly next week I will test that as well. We have also discussed 10 blades, and its worth testing them all back to back I think.

What I am going to do is re-run the 9 blader over the weekend with the new 10Ah 30c batteries, and get a new baseline for the rotor as these new packs are holding a pretty high voltage under load compared to my scrappy 3yr old 5000 packs I was using

Oh and did you guys notice the new Alloy spinner?? Makes it so much easier to do final balancing for a really smooth fan, and looks great too!
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Old Nov 07, 2013, 12:11 AM
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Arngeir Blakseth's Avatar
Molde, Norway
Joined Jan 2001
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Yeah I noticed the shiny new spinner.
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Old Nov 07, 2013, 08:53 PM
deltas are cool
AIR SALLY's Avatar
Tehachapi ,CA.
Joined Apr 2006
20,794 Posts
well back in the day the Ramtec was loaded more than the 11 blade dynamax and kept our poor 65-91 glow motors from blowing Rods.you hav'nt lived untill you blow a rod at 25,000 rpms the sudden stop throws blades everywhere,dont ask me how i know. from the EDF versions Ramtecs i have seen fly they seem really fast once on step ,but have less stactic thrust at lower speeds.....im thinking use some spacers and try a 7 or 8 blade.lower amp draw and higher Rpm.(remove the blade and use pieces of the foot to make spacers)
Great idea to have a alum spinner .....at the rpms EDF motors can turn i would feel alot safer with a nice alum spinner
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Old Nov 07, 2013, 09:34 PM
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Fontana, California, United States
Joined Jul 2004
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Well i knew when i got a Ramtec to spin 30k my work was done Rodger is correct, static the load is lower. Ramtecs load up after 50mph and even the sound changes! I did lots of Ramtec testing as well as Dynamax and Turbax. I have tons of data from 4 years ago before Tony and i ever exchanged an e-mail.
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