Testing 90mm Midi fan @ nearly 10 Lbs thrust - RC Groups
Thread Tools
Apr 07, 2008, 08:37 PM
Registered User

Testing 90mm Midi fan @ nearly 10 Lbs thrust

New 1/7/09 SEE PAGE 27 for photos and personal opinions.
Medusa's new 80mm length 1100kv motor (14.2oz) tested in Wemotech Midi fan. A BIG thanks to Tom Bacsanyi for sending me this motor to test! Eventually, I'll have my own but patience is not one of my better qualities. Thanks Tom.
Two new features of the Medusa;
1. Wires exiting the side of the can instead of straight out the rear keeps me from having to bend the wires 90 degrees to exit the exhaust cone AND these are long enough that I did not need to add extensions to exit the cone.

2. The motor shaft is flat on one side so the adapter's set screw will be kept from spinning on the shaft.

Tests used Castle Creations HV85 controller, 72mm exhaust, Medusa's Power Analyzer Pro and software for a computer controlled test. Lipos are expensive so I'm not testing the motors longevity on the thrust stand, just its capability in a short test. The test consists of a linear ramp for 0 to 100% throttle over 15 seconds and then held at 100% throttle for 4 seconds so the voltage, rpm, etc can level out a bit for an accurate reading. The computer catches readings 4 times per second and gives tons of info. I've also set up an Eagle Tree air speed indicator to catch the airspeed of the exhaust.
I heat the lipos from the 62F ambient to about 104F as they perform better when warm (hold voltage better) and when in flight your packs will easily exceed 104F (mine typically are 120F). Wemotech Midi fan w/ inlet ring and 9" long tail cone.
The most accurate test would be one where the desired flight packs would be used so you could see exact voltage drop and amps for this set up. These tests tend to run me through lipos so I've started doubling up the lipos in parallel to save some wear and tear on my lipos. Consider that you will likely see a lower voltage with flight packs using half the capacity. Thunder Power Extreme V2 3850 packs used.

No load kv test,
11.43v, 1.8A, 20.0 W, 12,975 rpm, 1135 no load kv

10s 7700ma (3850s in parallel) heated to 105F
41.85v dropping to 37.6v, 58.7A, 109.6oz T, 2212.5 W, 38,175 RPM, 1013kv under load, 174 mph eflux
11s 7700 98F, 45.8v - 40.26v, 67.2A, 125.1 oz T, 2705 W, 40,350 RPM, 1002 kv under load, 190mph eflux
12s 7700 105, 50.18v - 43.7v, 75.6A, 142.0 oz T, 3335.5 W, 42,975 RPM, 980 kv under load, 200mph eflux.

The 80mm long motor has 51mm of its length protruding from the rear of the fan. The Medusa heat sink is 38mm long so you'd get full contact w/ this long motor.

ARC motors tested 1/9/09 SEE PAGE 27 for photos and opinions
Thunder Power Extreme V2 3850 packs used as well as Zippy 3500 30C packs as noted.

ARC 36-75-1 1680kv 75mm long motor, 12.7 oz w/ connectors
No load Kv test,
11.43v, 1.98A, 22.0W, 19,225 RPM, 1682 no load Kv
Installed in Midi fan
6s 7700ma (3850+3850) heated to 104F
24.95v dropping to 22.38v, 70.7A, 88.1oz T, 1589.5 W, 34,450 rpm 1536kv under load, 165mph eflux

7s 7700ma 106F, 29.1v-26.1v, 94.4A, 118.3oz T, 2475 W, 39,225 rpm, 1501 kv under load, 194 mph eflux

ARC 36-55-2.5, 1100kv motor 55mm long, 8.2 oz with connectors
No load, 11.58v, 0.685A, 7.0 W, 12,950 rpm, 1,118 no load kv
10s 3500 30C htd 104F,
41.95v - 38.0v, 52.8A, 105.3A, 2026 W, 37,000 rpm, 966.6 kv under load, 182mph
11s 7700ma 105F,
45.98v - 41.3v, 60.3A, 121.2 oz T, 2517.5 W, 39,575 rpm, 950kv under load, 193mph eflux
12s 7700 98F,
49.94 - 43.58v, 66.7A, 133.9 oz T, 2931 W, 41,250 rpm, 945 kv, 202 mph eflux

The ARC motors came with 4mm bullet connectors attached and with female bullets for the ESC. Nice touch. The wire inside seems a bit thicker than the Medusa motors I've tested in the past but the wires leaving the motor to the ESC are smaller than the Medusa's. The 75mm can ARC doubles up the wires to address this issue. There are two yellow wires to one bullet, two greens and two reds. Not judging as I honestly do not know how thicker wire inside or out affects performance or what draw backs or gains could be involved. Passing along what I see, you be the judge.

Previous test of another ARC motor
ARC 36-55-1.5 motor tested in Midi fan
My tests use the Midi inlet ring. A custom built thrust stand and Medusa Power Analyzer Pro and Medusa's software so that the computer controls the entire test. The exhaust cone is about 9" long and the exit diameter is 72mm. My basement is cold so the packs are heated to perhaps the average temperature the packs would see in flight.

6s Thunder Power Xtreme cells heated to 105F. These cells have 45 cycles and are not holding voltage as well as newer packs as you will see further below w/ Zippy packs.
24.95v dropping to 20.28v, 73.46amps, 85.4 oz Thrust (5lbs 5.4oz), 1490W, 33750 rpm, Kv under full load was 1652.8, efflux velocity of 168mph

7s Thunder Power Xtreme cells heated to 105F, again packs not holding voltage great.
29.17v-22.9v, 89.88 amps, 106.7 oz T (6lbs 10.7oz), 2080W, 36950rpm, Kv
under full load was 1604, efflux velocity of 186mph

6s Zippy 3500 30C packs that are much newer. Heated to 102F
25.0v-21.41v, 79.94 amps, 95.5T (5lbs 15.5oz), 1716W, 34850rpm, Kv under
full load was 1617, efflux velocity 176mph

No load test
11.73v - 11.56v, 1.385 amps, 15.5W, 21,750rpm, no load kv 1879.9

At 80amps on 6s there was no need to test fresh packs on 7s as the amp draw would have easily exceeded 90 amps and my HV85 could get unhappy. The motor may well handle 7s but you may want to have an HV110 in use.

I encountered no problems w/ these motors and intend to test the 1100kv 55mm long motor in a jet eventually. Will report on longevity when that opportunity comes. Would prefer it to be longer to better handle the 12s I want to put it on. May be fine but I'd feel better if it were longer.

Earlier testing from mid 2008 ish.
More testing of Medusa Research Afterburner motors. Now testing the new V2 series long can (60mm) motors.

36-60-1500 Motor, 85HV ESC, Wemotech Midi Fan, 74mm exhaust diameter and thrust tube extends 9.25" beyond rear of fan, Medusa's Power Analyzer Plus system

8s 3850 Thunder Power Extreme pack heated to 105F before testing (cold in my work area).
Volts Amps Thrust oz Watts RPM
29.3 81.8 127.4 (7lbs 15.4oz) 2429 38525 Kv (taken from full throttle data after rpm and voltage leveled) 1310

9s 3700 (new 5s Evo 20C and older 4s Polyquest 20C) pack heated to 100F before testing
31.3 92.6 145.8 (9lbs 1.8oz) 2951.5 41225 Kv 1300 (sampled same as above as are the remaining)

9s 3850 Thunder Power Extreme pack heated to 106F before testing
32.5 99.5 155.2 (9lbs 11.2oz) 3295.5 42425 Kv 1294

Previous testing using version one 36-50-1600 w/ same outlet tube for comparison to above

9s 3850 Thunder Power pack don't believe I heated the packs for testing so likely 65F
30.8 90.8 138.4 (8lbs 10.4 oz) 2907 41125 Kv 1290

8s 3850 Thunder Power pack
27.6 76 113.9 (7lbs 1.9oz) 2180 37475 Kv 1320

Biggest difference is that I believe the 1500kv V2 can handle the 9s set up where I have been hesitant to hold full throttle for very long on just 8s with the shorter can 1600kv in my Savex L-39 and Fly fly Sabre.
Oh yeah, and an extra pound of thrust is nice too.

NEW TEST of 1300kv V2 long can
1300kv 60mm length V2 test in Midi fan. 74mm exhaust diameter.

10s 3700 older 20C Polyquest packs heated to 104F and this test after a very short failed test. Inlet ring came off. No recharge between.
37 73.8 138.1 (8lbs 10.1oz) 2756 40675 Kv 1095

11s 3850 Thunder power extremes heated to 100F
39.3 83 155.5 (9lbs 11.5oz) 3317 42975 Kv 1085

New info added 8/13/08
9s 3850 thunder power extreme V2 packs heated to 100F
33.5 61.9 112.6 (7lbs 0.6oz) 2084 37,300 Kv 1114

10s 3850 thunder power extreme V2 packs heated to 97F
36.84 76.2 138 (8lbs 10oz) 2836 41025 Kv 1106

By the end of April RC Sport Flyer Magazine will have printed the review of the Savex L-39 and I'll post a link here to the video which includes a radar set up to show speed from the speed passes on both 10 and 11s set ups.
www.rc-sf.com is where the video will be.
I have had many flights using the original 50mm can 1600kv motor on 8s with no issues in two jets. I run 15 - 20 second full throttle dive, pass and climb with mixed flying between speed passes.
The V2 60mm long can 1300kv motor was really kicking ass on 11s in the L39 at over 3300 watts installed. Sound was incredible. Got 5 flights before motor demagged (lots of full throttle passes). 3300 watts is many times the recommended rating. 10s was also tested in the L39 and proved to be incredibly fast even on the cheaper cells. I have another 1300kv motor on the way and will be flight testing 10s using some new Thunder power packs that will hold better voltage under these loads. 10s w/ some throttle management should work fine for this motor. I will find out and report whatever the verdict.
for previous 90mm fan testing see following

9/2/08 Medusa 1600kv 60mm long can motor tested. 74mm diam exhaust. Midi fan w/ inlet ring attached. HV85 controller.
6s 3850ma Thunder Power Extreme V2 packs heated to 101F
25.1V 59.6A 80.5oz (5lbs .5oz) 1266W 32,275rpm

7s same packs heated to 103F
25.1V 77.1A 105.8oz (6lbs 9.8oz) 1956.5 W 36,825rpm

8s same packs heated to 102F
28V 93.6A 130.9oz (8lbs 2.9oz) 2648W 40,550rpm

For tests on 96mm fan look here;

New test 11/3/08
Medusa's MR-36-60-1800-5 1800kv motor on 6s in the Midi fan

5s 3850mah TPx packs in Wemo Midi fan, packs heated to 95F.
20.92v dropping to 17.74v, 56A, 62 oz T, 1005W, 28,600 rpm 1607Kv under full load
3lbs 14 ozs thrust

6s new zippy 3500 30C lipos heated to 100F, Wemo Midi fan
25.06v dropping to 21.62V, 79A, 89.8 oz T, 1717.5 W, 33,875 rpm 1560Kv under full load
5lbs 9.8oz thrust

Here is the niche this motor fills. A Kv optimized for 6s lipo so that an expensive High Voltage controller is not necessary while keeping under 80amps. Keeps cost of other components down. Can also use 3850ma packs instead of larger 5000 ma packs.
Last edited by EDF Guy; Jan 07, 2009 at 10:07 AM.
Sign up now
to remove ads between posts
Apr 07, 2008, 09:50 PM
Registered User
Tempest's Avatar
Hi Carl!

I just finished reading your article in RC Sport Flyer and then I saw your new post. Nice job on the testing. The numbers you've posted look interesting enough to have me take a look at Medusa's offerings. In particular, I have a Jet Hangar Sabre that I'm looking to equip with a 8-9S midi fan solution. The 36-60-1500 on 8S could be a reasonable candidate. Do you have any partial throttle readings (i.e., 25, 50 and 75% throttle)? (81.8 Amps at full throttle would certainly burn through a 4900mAh pack in no time.)

Is there anything you can say relative to Herb's observations I have read elsewhere regarding the cracked shafts on some of these motors? Has this been addressed in the new V2 motors?

I've read on other posts that anything above 1800 watts on the midi fan might be asking for trouble, but you seem to be pushing this fan to over 3000 watts. Impressive to say the least. Does anyone else have any thoughts on the safety of this many watts in a midi fan?

Let me state up front that in no way am I trying to instigate anything, but rather I am a potential customer seeking to just understand the facts.


Apr 07, 2008, 09:59 PM
EDF rules... :)
AirX's Avatar
1500Kv is getting pretty close to a sweet spot in a Midi. I need to look into the new v2's.

Eric B.
Apr 07, 2008, 10:54 PM
Suspended Account
lavochkin's Avatar
Whats up Carl?? I think your on the verge of needing the hv-110 eh??? Your pushing that 85 pretty hard! Hey its making though right? You always do good motor reviews Carl. Keep em up. How much more $$ are the new longer can motors than the shorter can ones ??
Apr 07, 2008, 11:29 PM
corsair nut's Avatar
i think they are around 115$ im getting 1500W on 8s in my himark fan with a turnigy 36-56-1200. i need to try about a 1500 60mmL motor, or a 1100 kv 60mm motor on 12s. ive got a 12s capable esc. 115$ is a little much for the medusa for me right now, i guess ill have to save, and live with the 1500W for now. well, it should be about 1650W once i install inlet/exhaust ducting. its 1500W with no lip or pipe. i know with the lip it will go up quite a bit. thanks for posting all your info on the midi, seems that not too many guys rea posting about them, so its kinda a stab in the dark on 90mm stuff these days. thanks again.
Apr 08, 2008, 12:28 AM
smug in granny panties
monkamarm2000's Avatar
yeah very cool stuff! Specially on the medusa's heard things here and there yeah, but mostly when its being treated like a lehner or a nue, but I think they should have lots of potenial right in the 1500 to 2kw range, specially for midi. past that you throw away 400 kw for every 100 through the fan, but if you can find a nice reliable 8 or 9s combo at 2kw your golden. heck that's tad better and cheaper than a hacker will do actually!
Apr 08, 2008, 06:40 AM
Registered User
Tempest, the tests were computer controlled. 0-100% throttle over 10 seconds and then held at full throttle for 2 additional seconds to allow volts and thrust to level out. I was getting 6 minute flights on 11s 1300kv set up and using only 2500ma of 3700 available. Averaged 3-4 full throttle passes with throttle management between. Full throttle all the time is just not my style and would be pretty hard on lipos and motor.
Herb has been at this a long time and is a bright guy. I have not read his observations on cracked shafts but have not experienced this in my testing on the bench or in the air. I just sent the demagged 1300kv back yesterday and could see no problem with the shaft though I pushed it far beyond the ragged edge.

I am not sure of the limitations of the Midi. At some point I am sure it would through a blade out the side. I hide behind a 3/4" think sheet of plywood during bench tests! The sound is amazing but scary in a confined area.

Joe, the longer can V2 motors are not much more than the first series motors and the extra size should help it handle the heat from these high power set ups. The longer cans also allow more contact w/ Medusa's heat sink. I like that their heat sink fins are inline with the air flow. The HV85 is not having a problem with these set ups. It is my understanding that they are capable of higher amp loads than what is on the label but need to have some airflow. I am not flying the 1500kv set up on 9s as it pulls nearly 100 amps and I don't feel comfortable pushing the esc or the batteries that hard.
Monkamarm, you are spot on when it comes to diminishing returns on extra watts. I am not sure of the exact best sweet spot. I do look forward to testing the 1300kv set up on TP V2 packs to see how it compares to the 11s set up. This should give a good idea of how many more watts are needed to accomplish more thrust/speed. The thrust still seems to increase big time as I jump in lipo count. I think the inflight speed will diminish due to drag of the model. Will find out!

thanks for the kind words all,
Apr 08, 2008, 02:27 PM
smug in granny panties
monkamarm2000's Avatar
yeah long as fan holds most times the thrust will jump in some form. if there was no blade creep or destruction a mini would do the same, just climb climb. but even if it could do it a mini on 20s wouldnt be as worth while as a larger fan on less count. And thrust isnt everything either, you can waste too much power just to get thrust, and tyhen velocity is sacrificed and you have a model that could tow a car but only do 50 mph in the air. Thats why I look only at thrust to watts to weight, this gives you a balanced plane that flies fast and well and efficiently.

Apr 08, 2008, 02:59 PM
deltas are cool
AIR SALLY's Avatar
any one got a link to the Medusa motors and who carries them.
Apr 08, 2008, 03:21 PM
Registered User

Also, they have testing on 50mm, 70mm and 90mm fans on their site.
Apr 28, 2008, 10:27 PM
Registered User
Tumbler's Avatar

HAve you done any testing with the 1300kv?


Apr 28, 2008, 11:11 PM
Registered User
kevin's Avatar
from first post

NEW TEST of 1300kv V2 long can
1300kv 60mm length V2 test in Midi fan. 74mm exhaust diameter.

10s 3700 older 20C Polyquest packs heated to 104F and this test after a very short failed test. Inlet ring came off. No recharge between.
37 73.8 138.1 (8lbs 10.1oz) 2756 40675 Kv 1095

11s 3850 Thunder power extremes heated to 100F
39.3 83 155.5 (9lbs 11.5oz) 3317 42975 Kv 1085
Apr 28, 2008, 11:21 PM
Registered User
Tumbler's Avatar
How the heck did I miss that. Duh. Sorry about that! 9s might be what I am looking for. 73 amps on 10s is a little high for me.



Originally Posted by kevin
from first post

NEW TEST of 1300kv V2 long can
1300kv 60mm length V2 test in Midi fan. 74mm exhaust diameter.

10s 3700 older 20C Polyquest packs heated to 104F and this test after a very short failed test. Inlet ring came off. No recharge between.
37 73.8 138.1 (8lbs 10.1oz) 2756 40675 Kv 1095

11s 3850 Thunder power extremes heated to 100F
39.3 83 155.5 (9lbs 11.5oz) 3317 42975 Kv 1085
Apr 29, 2008, 05:50 AM
Registered User
After burning up the 1300kv motor on 11s I have put in a new 1300kv motor and no have 7 flights on 10s with no issues.

In just a day or two the video will be up of my Savex L39 with the 10 and 11s set ups using 1300kv motor in Midi fan. Check www.rc-sf.com. I'll post a link when I see it up.
Apr 29, 2008, 08:58 AM
Registered User
kevin's Avatar
no 1300 v2's in stock right now. i will probably get one for my tam f-16.

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Found used 90mm midi fan to test a motor MustangAce17 Aircraft - Electric - Jets (FS/W) 9 Dec 12, 2007 04:25 PM
WemoTech Midi Fan (90mm) - Actual Thrust Request AeroJDK Electric Ducted Fan Jet Talk 2 Jul 30, 2005 01:13 AM
1.2 lbs static thrust from MIDI fan alabamaboatguy Electric Ducted Fan Jet Talk 16 May 14, 2005 08:29 PM
How much thrust from a Wemotec Midi fan? KC10Chief Power Systems 3 May 27, 2004 11:52 PM
Hacker B50 11L and 90mm Midi Fan Arthur Knowles Electric Ducted Fan Jet Talk 5 May 21, 2003 11:40 AM