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May 16, 2017, 11:47 AM
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Sukhoi Su-35 Flanker twin edf 70mm


Got this one from HK for $215, airframe only - but with complete metal landing gear, some servos (gear door) and a simple gear door sequencer.

http://sz-freewing.com/

http://www.f-hobby.com/freewing-su35-pnp-and-kit-p-66

https://www.motionrc.com

https://www.motionrc.eu/collections/jets-and-ducted-fan

https://www.rc-castle.com/index.php?...th=470_507_508

Had no use for the junk fans, junk outrunner motors and escs that the pnp version comes with for an extra $150

The original Sukhoi Su-35 has a wingspan of ~ 15.3 meters and a length of ~ 21.9 meters,

https://en.wikipedia.org/wiki/Sukhoi_Su-35

whereas the model has a wingspan of 108 cm and a length of 163 cm, which gives as an approximate scale ~ 13.8 : 1 .

Some but not all Su-35's have thrust vectoring ... the Su-37 variant does as well.

The original is not a slow floater jet ... Top speed is ~ 2400 km/h or Mach 1.94

Will be repainted in a different camo scheme, similar to the one shown below.

Power will be from twin WeMoTec MiniFan EVO 70mm or a comparable 10-bl setup, with either a HET 2w, Arc or Mad Thrust, or similar , quality in runner motor on 6S.

A proven setup very similar to what I have in my Sukhoi Su-47 Berkut :

https://www.rcgroups.com/forums/show...0mm-EDF&pp=100

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Video of the maiden :

Su-35 Flanker by Freewing Maiden - Twin CS-10 70mm Inrunner Fans (3 min 54 sec)
Last edited by Herb; Jul 19, 2019 at 12:52 PM.
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May 16, 2017, 12:02 PM
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A few pictures of the original (some Su-35's and Su-27's mixed in), there's lots of different cool camo schemes to choose from:

http://www.airliners.net/search?keyw...display=detail

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Last edited by Herb; May 16, 2017 at 08:43 PM.
May 16, 2017, 12:04 PM
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The Su-27 / Su-35 is also - for good reason - quite popular as a large turbine model (single or twin) : (btw one is a MiG-29)

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Last edited by Herb; May 16, 2017 at 12:10 PM.
May 16, 2017, 12:07 PM
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The plan is to paint mine in a scheme that will vaguely resemble the one below,

[reference : http://www.naritafamily.com/scalemodelTOP.htm ]

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Last edited by Herb; May 16, 2017 at 08:37 PM.
May 17, 2017, 12:10 PM
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I ordered the fan-less version ...

But the original Freewing kit came with two plastic 6-blade fans that look a bit like cheap wemotec copies, the sound seemed horrendous from the videos ?

https://www.motionrc.com/products/fr...pare-parts-tab

The newer version includes a new improved (soundwise) 12-bl Freewing fan:

https://www.motionrc.com/products/fr...p#upgrades-tab

For some odd reasons the twin FW fans are counter-rotating (perhaps a sebart mig29 heritage) which makes swaps & upgrades even more challenging, as there's now two versions of each

I could not find any weight figures anywhere for any of the fans. EDIT found some on RCC.

But I suspect the new 12-bl with metal shroud & parts are quite heavy ~ 270g (like the FW F-16 90mm stock metal fan which weighs a rather hefty 600g with motor). So two of them here in the Su-35 would be a hefty 540g ...

The new Freewing "2938" 2085kv, 165g inrunner is ~ comparable in weight to a HET 28mm 1W-40 motor : http://www.effluxrc.com/HET-2W-40-17...r-HET1W-40.htm

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Last edited by Herb; May 17, 2017 at 06:45 PM.
May 17, 2017, 12:46 PM
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In setting up the model, I always like to see how the original flies

Here's a representative video, taken at the Paris Airshow at Le Berguet :

Paris Air Show 2013 - Su-35 vertical take-off + Air Show (HD) (8 min 16 sec)
May 17, 2017, 12:48 PM
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Here's a nice video of a twin turbine one in the UK, set up with just tailerons & flaps. No thrust vectoring, like the original one...

GIANT 1/6 SCALE RC CARF SUKHOI SU-27 "FLANKER" - TWIN TURBINE COLD WAR FIGHTER - 2017 (9 min 48 sec)
May 17, 2017, 11:44 PM
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This is a really nice airframe, it looks great in flight, flies really nice and has a nice size to it. A friend of mine had one, I loved seeing it fly but I always hated the fans. The Mini Evos will be a nice addition! One thing I noticed is the design was at times prone to pulling in foreign objects from the runway. The nose wheel location is a contributing factor, and the nose fender does not actually work like the real one does so some of the kick up can be thrown / pulled into the inlets at high power takeoff runs. I am not sure how the Evo will handle FOD. The cheap 6 bladed fans disintegrated upon threat of FOD let alone any contact with it. One method of controlling FOD by my buddy was to place a mesh screen in front of the fan... for some losses obviously.

I always wondered if a servo actuated screen could be tied into the gear channel so you could have FOD prevention on takeoff but not the losses in flight.

Hopefully you will not have to deal with this on your field. The runway my friend was flying from had large but light weight chucks of asphalt chips that would go into the inlets. I wonder if it would be less an issue on dirt or decomposed granite.
May 19, 2017, 04:30 PM
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The old version must have had some cheap junk plastic fans that were horribly out of balance, I think the sound might have been a lot better if an effort had been made beforehand to balance them a bit

The newer PNP version has some 12bl fans in with some cheap outrunners. I did not want those either.

I went with the "no fan" version so I can install my own, better fans with better motors.

Yes there is always a risk of ingesting something on takeoff, I have old fans that came out badly chipped after one or two years of flying, on the DS carbon fans I would plug the chips with hysol and sand smooth after that

I agree that with the WeMoTec EVO fans the blades are quite thin, so fod ingestion would most likely take all the blades out. A metal sieve fod screen in front of the fan might work, I use plastic fod screens for the cheaters. I guess I will take my chances

I also agree that the nosegear wheel is often the culprit, my Hawks love to ingest stuff, but never on F-16s ...
May 19, 2017, 04:36 PM
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Here's what I have used as fod screen on the bottom of edf jets (at the cheesegrater intake) :

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May 21, 2017, 12:12 PM
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Here's a few pictures of the model itself, there's a few steps and sharp angles at the intakes that need to be sanded out.

The two cheesegrater intakes are actually almost invisible, and at more or less the right angle.

The measured intake is about 85% FSA for a 70mm, which is quite adequate even without the cheater intake.

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May 21, 2017, 12:17 PM
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Even though not all Su-35's have thrust vectoring,

https://en.wikipedia.org/wiki/Sukhoi_Su-35

the model TV setup, requiring three extra 9g servos, is nicely made and works quite smoothly. It does require a 9-ch receiver to do all the TV-to-flying surface mixings appropriately (and still have one channel open for the gyro gain) ....

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Last edited by Herb; Jun 21, 2017 at 03:50 PM.
May 21, 2017, 12:21 PM
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Mine is an airframe only kit, so it came with no fans ... I believe they must have been rather similar to these Su-47 6-bl plastic Banana fans that I tossed,

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May 21, 2017, 12:24 PM
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The first fan option would be twin WeMoTec MiniFan EVO 70mm fans, the would require inrunner motors that are 29mm diam (Arc, HET) so that they fin in the shroud,

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Last edited by Herb; May 25, 2017 at 12:33 PM.
May 21, 2017, 12:26 PM
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The second option would be the Freewing $12 plastic 12-bl fans, which again fit nicely and seem to perform decently, fan weight with plastic spinner = 59g

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Last edited by Herb; May 24, 2017 at 01:24 PM.
May 21, 2017, 12:31 PM
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The third option would be the almost exact same setup I ended up with in the Su-47 Berkut which has worked very well, twin $18 CS 10-bl V3 fans with alu spinners (12-bl shrouds with more efficient 10-bl rotors) with twin MT 29mm long can inrunners, fan weight with alu spinner = 63g

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Last edited by Herb; May 24, 2017 at 01:27 PM.
May 23, 2017, 09:40 AM
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Did you make a final decision on power??

Also, are you planning to use the TV setup or immobilize them?
May 24, 2017, 11:55 AM
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Hi, I have ordered most of the components ...

I have two WeMoTec EVO 70mm setups tied up in the FW F-104 and FW F-16, so on this one I will go instead with a setup that is almost identical with what I have in the Sukhoi Su-47, which seems to work quite well. : https://www.rcgroups.com/forums/show...0mm-EDF&pp=100

* Ultra reliable Twin yep 100A escs from HK, 81g

* Twin HET 2W-27/2W-30 inrunner motors, 115g ... or MT 2960 2200kv 195g motors

* Twin CS 10-bl fans, 63g (I have also the 12-bl and 14-bl, sound is good but the efficiency is pretty bad, tried them out in the Me-262).

The freewing 12-bl looks a bit flimsy to me, the CS 10bl seem a lot more solid, both in the rotor/alu spinner and the shroud.

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Last edited by Herb; Jun 05, 2017 at 10:54 AM.
May 24, 2017, 12:15 PM
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Regarding the thrust vectoring, I am still thinking about it ...

Not all original Su-35's have TV, so that might be one reason not to have it. Also, those TV units cause a lot of turbulence when deflected, there's a rather sharp step in there, on one side. Also, to do it right, you need a 9-channel receiver, so I would have to use one of my my Futaba S-bus R3008SB receiver on the T14G. Remember, one channel on mine is for gyro gain. The TV needs three additional channel/mixes (eg. FLAP, AUX1,AUX2).

If no TV is used then you can just fix the TV units in place with screws and/or dabs/fillets of silicone, which are both removable later.

Nevertheless the additional complexity/weight for TV is just 3 x 9g MG digital servos, which is not too bad. Also, I think it is possible to set up the TV units with just some simple combination of inexpensive & lightweight v-tail mixers & possibly servo reversers (which work fine with my Futaba receivers), since the original mixing are just simple linear mixes. The relative throws on the TV units can then be adjusted mechanically to suit taste (eg low setting on first flights). The downside is that now the TV is always ON, since it gets difficult to put the whole TV 3-servo setup on a single switch (setting just some TV's on a switch seems silly).
Last edited by Herb; Jun 21, 2017 at 03:51 PM.
May 25, 2017, 01:51 PM
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Another very nice video of a turbine Su-27 flying jet-like, like a Sukhoi should fly From what I recall the original Su-35 has thrust/weight ~ 2
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RUSSIAN R/C SUKHOI SU-27 FLANKER TURBINE MODELL JET with a JetCat P180-RX (5 min 36 sec)
Jun 01, 2017, 07:50 PM
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Motors and fans (but not esc's) are here, time to statically balance the 10-bl rotors, install the motors in the fans, and test-run both of them ...

CS 10-blade fan V3 with alu spinner $18 :

http://www.rc-castle.com/index.php?r...roduct_id=3106

http://www.rc-castle.com/index.php?r...roduct_id=3037

MT 2860-2200kv inrunner motor from HK $32 :

https://hobbyking.com/en_us/dr-mad-t...___store=en_us

YEP 100A 6S esc from HK $44 :

https://hobbyking.com/en_us/hobbykin...___store=en_us




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Last edited by Herb; Jun 05, 2017 at 12:08 PM.
Jun 01, 2017, 07:52 PM
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I got these inexpensive & simple servo reverser and v-tail mixers to see if I can dispense with some channels on my Futaba FASST receiver ...

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Jun 03, 2017, 03:02 PM
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Rotors were a bit out of balance, and needed to be balanced on a magnetic balancer. The rest of the fan setup will have to be re-checked later...

The alu adapter could be off-center as well, and the motor itself could be slightly off balance too.

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Last edited by Herb; Jun 05, 2017 at 12:20 PM.
Jun 03, 2017, 03:03 PM
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One of the alu adapters needed to be reamed out a bit so that it would go all the way in on the motor shaft, otherwise it can cause extra vibrations at high power...

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Jun 03, 2017, 03:05 PM
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There is a problem with the way the fan shroud is designed, it works well presumably on an outrunner, but for an inrunner the front cooling holes are completely blocked

They need to be opened out to give plenty of airflow inside to motor, otherwise there is a good chance the motor will roast eventually or melt the shroud

Also on this CS 10-bl V3 fan the fan rotor looks pretty strong (fiber-reinforced plastic), but the shroud seems cheap flimsy plastic.

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Last edited by Herb; Jun 03, 2017 at 03:11 PM.
Jun 03, 2017, 03:17 PM
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Sometimes I have checked again for fan vibration after the whole thing was installed in the plane, but I think there is a better way to do it on the bench, with the fan very solidly mounted ,

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Jun 04, 2017, 02:01 PM
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Almost done putting the fans together Took a bit of work to do it right ...

To avoid any sort of vibration the motors need to be supported at the back, I used masking take and ge silicone ii.

To four m3x6mm screws received loctite and ge silicone as well.

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Jun 04, 2017, 02:07 PM
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Finally put together and balanced

The inrunner motor was pretty well balanced to start with, and so was the aluminum spinner, so no further balancing was needed.

The complete fan unit weighs 233g ...

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Fan no. 1 :

Fan no. 1 (0 min 8 sec)


Fan no. 2 :

Fan no. 2 (0 min 7 sec)



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Last edited by Herb; Jun 07, 2017 at 07:21 PM.
Jun 05, 2017, 09:56 PM
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Thanks for the update.... I enjoy watching your builds!!

Mike
Jun 06, 2017, 11:34 AM
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Thanks !

Things that at first look rather simple end up taking quite a bit of time ... still waiting on ESC's and some servos.
Jun 07, 2017, 12:24 PM
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Pretty much set on setting mine up same way as the Composite Arf twin turbine one, which flies like a charm jet-like with good speed.

TV setup will be epoxied in rigid, removing all that junk hanging off the bottom..

http://carf-models.com/en/products/sukhoi-su-27-su-30

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GIANT SCALE Sukhoi SU-27 TWIN ENGINE JET (CARF Models): Weston Park 2016 (9 min 33 sec)
Jun 07, 2017, 05:26 PM
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Always works like that doesn't it.

It's worth the time to do right though. Your Fan sounds very nice. It should be a sweet setup

I recently balanced some CS70 fans with HET 5W motors. I have the entire range nicely balanced except for a band at somewhere around, estimated, 10,000 rpm. It vibrates there. I have been avoiding that specific throttle setting as a result in flight. I have two fans in this model and they both do it at that exact range. The spinners are nice and true but I suspect the rotor mold for the spinner on these CS70's is slightly off... the spinners need to be "clocked" at a certain spot no matter what the balance is due to the fit. It's been a challenge to find the right spot for a slight amount of weight inside the spinner as a result. I have two more identical fans and motors as the project was originally a 4 engine one so I'll spend more time on those other two fans and see if I can get it better - then I'll swap those units into the working shrouds if it works as hoped.

Like you said... at first seemingly simple things, and time.
Jun 07, 2017, 07:17 PM
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Hi Eddie, thanks.

Mine ended up pretty well balanced, clocking the alu spinner and adding tiny weights to the inside of the spinner did not improve anything. So I called it a day.

The fans, even if perfectly balanced, can resonate with some natural frequencies of the shroud. That is hard to eliminate, unless you use a very stiff (alu) shroud.

With multiple fans you have the problem of fans resonating with each other (beats). How and when they resonate depends on how they are mounted. The more rigid, the higher the damping.
Jun 11, 2017, 12:56 PM
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Will definitely put a sieve net protection on the two cheesegrater intakes (not the main ones at the) of the Su-35.

Had major blade wear - in just a month of flying, maybe 10 flights - on my F-16 from fod intake at the bottom cheesegrater intake, will put a screen on that one.

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Jun 11, 2017, 01:01 PM
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$12 S-bus signal converter for Futaba receiver from bangood, increases channel count from 8 to 8+4 on my standard Fuataba s-bus receivers.

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Jun 15, 2017, 02:05 PM
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The two ESC's have finally arrived (from the Netherlands ??) so work can continue.

Need to solder connectors, fabricate extension wires, reprogram both esc's with the prog card, then re-test each motor separately.

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Jun 18, 2017, 03:05 PM
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Twin fans ... twice the work

Soldered up the connectors, programmed both esc's, check for rotation direction, ran up both fans again for a test ...

Prog card setup : 6 deg (low) timing, brake off, low volt cutoff off, freewheeling on, spoolup plane medium, pwm freq 8kHz.

That's the same identical setup I have in all my other edf's with YEP (6S or HV).

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Last edited by Herb; Jun 18, 2017 at 03:25 PM.
Jun 21, 2017, 12:31 PM
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Found a suitable fine steel mesh in the cooking section at welmert ($3 strainer), easy to cut and install

https://www.walmart.com/ip/Mainstays...ainer/15042727

Seems to have just the right mesh spacing, not too coarse and not too fine. Testing it out in the FW F-16.

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Jun 28, 2017, 09:40 PM
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Herb

Do you use the internal BEC on the yeps or are you using separate power for your servos?
Jun 29, 2017, 12:10 PM
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The two YEP BEC's are plenty, no need for extra weight from one more BEC

Been busy with work & flying lately so not much progress yet ... all the parts are here though.
Jun 30, 2017, 09:27 PM
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Cool.... I'm doing the same type project with a fly fly mig.... was wondering if I could simply Y the two yep becs
Jul 01, 2017, 04:06 PM
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Absolutely ...

Occasionally in the old days there could be a problem, the fix was a "buffer" receiver pack added on that would even out any resonances between the becs. That is what I have in the twin90 Rafale, with two Kontronic esc's both with bec plus a rec pack. But today I think that's superfluous.

I have the same exact twin bec yep setup in the Su-47, no issues.
Nov 12, 2017, 10:18 PM
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Did you ever finish this SU??
Nov 13, 2017, 01:01 PM
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No ... not yet ! I do have all the components though, just short of space.

The Su-47 Berkut twin edf lasted a lot longer than expected ,

https://www.rcgroups.com/forums/show...0mm-EDF&pp=100

so this one is still waiting for space to free up in the garage !

The Su-47 Berkut has had many flights and is a major show stopper, but is still a labor of love & work in progress since I had to swap out taileron servos twice due to them going bad.

The very nicely made Freewing 70mm F-104, 70mm F-16, 70mm Hawk and esp. the 80mm A-4 have been a distraction too ...

How is yours doing?

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Nov 13, 2017, 03:45 PM
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Long story short, while a buddy was setting up to take off at Jet Jam, one of the power systems opened up full throttle and stayed open. I was standing next to him and saw he had the throttle off... It ran off the field and did damage. I returned the fan/esc to motionrc and they gave me some credit. Im waiting on hobbyking to hopefully get some of the ARF versions like got so I can simply rebuild with a new airframe and more power. I'll either use two of the light weight FMS fans or two XRP 13bs.

You're right... so many new planes coming out, it is hard to keep up. I just dug out a 90mm aeronaut F9 that I've had for years to possibly start that build, I'm replacing the power in basically all my current jets and I've got a pile of kits. Hard to keep up sometimes

And that 47 IS WOW COOL
Nov 13, 2017, 08:27 PM
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Two FMS inrunner 70mm fans sounds like an excellent option to me !!

http://www.fmsmodel.com/fms-70mm-duc...v1850-motor-6s

https://www.banggood.com/FMS-70mm-6S...r_warehouse=CN

(note that it says inrunner in the title but the picture shows an outrunner which is slightly confusing )
Jan 24, 2018, 02:08 PM
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Got around to doing a bit more work on the Flanker ...

This was an airframe-only kit so it had no servos.

Installed a bunch of Corona 9g and 17g digital servos (from HK) in all the right places, the only concern was to have plenty of torque and no slop on the two tailerons.

All the servos were installed with their plastic cover on top, nevertheless they were all glued into place as well with GE Silicone II.

Replaced the flimsy taileron plastic clevis with a steel one.

I did add the two servos required for thrust vectoring ...

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Last edited by Herb; Apr 23, 2018 at 12:20 PM.
Jan 24, 2018, 02:13 PM
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I might go with my standard Futaba TG 14-ch radio, or try out my new 16-ch Taranis Q X7 (full range with telemetry) I got from Amazon for $105 :

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Jan 28, 2018, 01:33 PM
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Here's what the FrSky X8R 16-ch full range telemetry receiver looks like when installed in the Freewing Su-35.

8-ch pwm outputs are on the right, s-bus output is on the bottom right (hidden from view), and telemetry input is on the left, next to the two diversity full range antennas.

My Taranis Q X7 Thread : https://www.rcgroups.com/forums/show...io&perpage=100

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Jan 30, 2018, 01:36 PM
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Done with a few more little things

This a very well engineered airframe, everything fits perfectly ! (unlike my BH Su-47 Berkut )

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Jan 31, 2018, 03:18 PM
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Even though my fans (esp. the HK MT long can motors & YEP 100A esc's) are a bit heavier than the stock cheap plastic ones, the CG came out just fine with a 5000mAh Roaring Top 6S battery in the nose !

Tested and re-tested everything (including esc endpoints, telemetry, TV mixing and switches) and she's about ready to go !

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Feb 02, 2018, 12:35 PM
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A few more simple straighforward modifications before the maiden ...

One is a very solid backstop on the nosegear, I do this on almost all of my edf jets (can't be done with that scale plastic rail since it's way too flimsy and won't do anything).

This prevents the nosegear strut steel pin from possibly bending back in a landing.

If needed, it can be removed just by pulling it out ... it is glued in with GE Silicone.


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Last edited by Herb; Feb 02, 2018 at 12:50 PM.
Feb 02, 2018, 12:46 PM
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The second mod is a steel mesh over the side cheesegrater intakes. One foam piece just broke off by looking at it, so it was time for the steel mesh.

The square intake on the Su-35 is ~44 cm^2 area, so that's about 147% FSA for the 70mm fans I am using - which is plenty. The Su-35 does not really need the cheesegraters, in fact they are probably quite detrimental in fast level flight...

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Feb 03, 2018, 01:38 PM
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I decided to add some very minor weathering to the Sukhoi, mostly using Tamiya weathering powders / pastels.

These are applied wet with a brush, let dry and then wiped off in the right direction with a wet sponge.

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Feb 04, 2018, 02:01 PM
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Had the maiden yesterday and it flew like a charm ... really no issues, had a bit of "up" in the elevators for safety which I then took all out in flight

A few clicks of aileron trims and she was going nicely.

With the most rearward CG at 155mm she was porpoising a bit on landing, maybe the elevators are not centering well, may need a stronger digital servo on those.

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Feb 04, 2018, 02:03 PM
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Unfortunately on the second flight I sucked in a stone on takeoff (presumably kicked up by the nose wheel) which destroyed my right fan entirely and caused a mild crash. Su-35 needs to go back to the hangar for some work

I have to find a way to prevent debris from getting sucked in in this one, the intakes are really low and this is going to be a recurrent problem.

A steel mesh at or near the intakes seems to be required ...

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Feb 05, 2018, 03:17 PM
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Looking at ways to configure the Su-35 intake grille without completely destroying the airflow (and thus the performance);

Here the Su-27 and MiG-29 as a guide.
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Last edited by Herb; Apr 02, 2018 at 03:13 PM.
Feb 07, 2018, 02:28 PM
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Took the trashed fan out and replaced the rotor with a brand new spare one (it's good to keep spares ).

Statically balanced the new rotor on a magnetic balancer, and then re-tested the complete fan unit on my test stand.

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Mar 31, 2018, 01:14 PM
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After sucking in a stone on takeoff and trashing the right fan (and some damage to the airframe) I decided I was not going to have that happen again

So I installed a steel wire mesh (cut out from a $3 welmert strainer) on the intakes, and a plastic mesh on the two side cheaters.

The steel mesh on the intakes is angled, so as to allow pass through more area.

The penalty in thrust, by comparing before and after, is about ~10% which is not bad at all and still flies the Su-35 exceedingly well.

I flew it again, and as expected there is some noticeable decrease in thrust but nevertheless it still flies fine on my setup.

A rather annoying fact was that yesterday I had in it a brand new FrSky XR8 receiver which would not give more than 50db no matter what the antenna orientation. Defective!! A friend at the field told me there has been a batch of bad XR8 receivers lately, a bad chip set, he had a few and retur
ned them.

With another good XR8 receiver now put in, I re-maidend it again, which showed that

(a) the thrust angle was still a bit off, needed a bit (a few mm's) of up thrust otherwise it would ballon with power off,

(b) it was a bit tailheavy and pitch sensitive at my CG (which turned to be aft of the the manual recommended CG)and

(c) on of the two taileron plastic linkages (the white plastic control horn) came loose.

After gradually adding 3 oz (84g) of lead in the nose, and massively re-securing all control horns with generous amounts of hysol inside and outside, I kind of re-maidened it again and this time finally it flew pretty well

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Last edited by Herb; Apr 02, 2018 at 09:24 PM.
Apr 02, 2018, 09:25 PM
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It seems I flew it originally with a CG that was behind the recomended 145-155mm manual CG (marked below by the two blue lines) ...
as a result it was a bit pitch sensitive.

.
Apr 06, 2018, 12:05 AM
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Will fly it some more to wring out all the throws and trim issues ... Installed a HobbyEagle gyro A3 Super II :

.
Apr 06, 2018, 12:07 AM
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Then after that it should be ready for a complete repaint

Will try these new acrylics from Spain ("Ammo by Mig") , they look nice !
.
Apr 12, 2018, 09:25 PM
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After a good flight last week the X8R receiver decided to just go dead - an not come back. Luckily the plane was back on the ground, see description here:

https://www.rcgroups.com/forums/show...er&perpage=100

It was suggested that I switch to a more robust receiver, the RX8R Pro (16-ch s-bus telemetry)

https://www.frsky-rc.com/product/rx8r-pro/

which apparenly does not suffer from the signal losses that some have experienced with the X8R (also 16-ch s-bus telemetry) I had in before.

I also update the firmware on all three X8R and the new RX8R, using the very convenient FrSky usb firmware updater :

https://www.frsky-rc.com/product/stk/



.
Apr 22, 2018, 01:33 PM
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Had three good flights with it today ... I really like the way this thing flies Very smooth & responsive.

It looks like the rear struts are a bit under-dimensioned ? Have been looking in my parts box for some thicker alu struts, the FW G-91 are close but about ~10mm longer. Could work with slightly smaller wheels.

Taranis QX7 radio with R8XR receiver & frsky lipo voltage monitor.

It's about time Freewing re-issues one of these with the new production quality standard (even though I like the lightness of eps here).

Pics from today at the field

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Apr 24, 2018, 08:10 AM
Dont forget the velcro straps
corsair nut's Avatar
those are great looking models! ive heard they fly real nice
Apr 24, 2018, 01:55 PM
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Yes if they don't disintegrate in mid-air ... thin beercooler styrofoam
Apr 25, 2018, 05:42 PM
Dont forget the velcro straps
corsair nut's Avatar
Keeps them nice and light though... i prefer eps honestly
Apr 26, 2018, 12:08 AM
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Yep they are nice ...

.
Apr 27, 2018, 11:58 AM
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Found the original factory paint still a bit unconvincing (mostly in texture) and went for a simple complete airbrush repaint,

.
Apr 28, 2018, 11:08 AM
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Cousins at the field yesterday Put a few flights on both (luckily or un-luckily they use different packs) ...

.
May 02, 2018, 12:28 PM
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I still get occasionally a low RSSI (receiver signal) warning message from the FrSky RX8R receiver, in the ~38db to 36db range, so it was time to add a second XM+ satellite receiver, way up in the nose.

The XM+ satellite (slave) s-bus receiver is tiny ! : https://www.amazon.com/Receiver-Fail.../dp/B01N5INCBH

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Last edited by Herb; May 02, 2018 at 12:34 PM.
May 03, 2018, 10:30 AM
Dont forget the velcro straps
corsair nut's Avatar
herb, it turned out fantastic with the new paint!!!! awesome!
May 03, 2018, 12:38 PM
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Thanks Brent !
May 03, 2018, 01:50 PM
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Resisted the temptation of giving the Su-35 that authentic "Russian badly worn look" , where eventually every panel line shows up as rust and black soot, and no two panels have the same shade / color

Somehow many times "showroom clean" or "airshow clean" and "Russian jet" don't go well in the same sentence ...

.
Last edited by Herb; May 03, 2018 at 01:55 PM.
May 09, 2018, 11:41 PM
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The grey one with a 74 mark is actually a Mig29UB. Just thought I'd put that out there. I know that you were referring to the weathered look, but I rarely see anything about the UB even though it's the far more attractive variant.
May 19, 2018, 01:04 PM
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Minor detailing on the engine, using Tamiya pastels ...

.
May 22, 2018, 02:27 PM
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the UB looks like its shortened
May 26, 2018, 07:44 AM
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Nice work Herb!
May 26, 2018, 11:20 AM
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Thanks Kevin !
Aug 19, 2018, 12:25 PM
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More details on the Su-35 steel mesh intake grilles ...

Due to the very low intakes the Su has a propensity to suck in any object (stone, twig, grass etc) on the runway . This is the only way I know of avoiding rather costly repairs

.
Aug 19, 2018, 01:34 PM
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nice ...looks clean
Aug 19, 2018, 03:56 PM
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Thanks
Aug 21, 2018, 10:59 AM
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Another thing that might be worth mentioning - besides the steel mesh on the intake, and the totally flimsy FF stab linkage setup - is the arrangement of the two esc's.

On mine one had the heatsink right against the outer foam wall ... not good, it gets no cooling air.

Best to rotate them out so the heatsinks get cooling, I cut some more black shrink wrap off of mine as well.

.
Aug 27, 2018, 01:05 PM
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After total destruction of my previous Su-35 due to complete signal loss with my Taranis QX7 + R8XR

https://www.rcgroups.com/forums/show...7-XR8-Receiver

https://www.rcgroups.com/forums/show...nis-Q-X7-Radio

I re-maidened the new one, this time with a Futaba FASST receiver & T14SG radio

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Aug 27, 2018, 01:07 PM
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On Saturday I had five good flights, it's nice to be able to parallel charge multiple packs at the field,

The CG comes out just right with the RT 6250's, anything smaller an it would start drifting towards tail heavy.

.
Sep 03, 2018, 11:57 AM
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Flight times : 3-4 mins is normal, depends on how far you want to stretch it ... The Su-35 is a very light airframe so throttle management works very well here !

I don't have the old six-blade (?) setup to compare, but I would think - given the current chinese foamy trends - that the new 12-bl setup is a lot more power hungry.

On mine the stock outrunner 12-bl Su-35 setup sucks ~2650W on that battery @ 57Ax 2, and delivers ~2.55 kg of thrust installed, which is not bad for a relatively inefficient outrunner setup. That gives a thrust^1.5 to watts ratio of ~48.6

On the Su-47 below the twin CS-10 inrunner motor (M.T.) setup sucks 3270W at 75A x 2, and delivers ~3.51 kg of thrust. That gives a thrust^1.5 to watts ratio of ~63.5 which is significantly (by ~ 30%) more efficient, as expected.

Ducting is quiet comparable in the two, with the Su-47 having a slight edge due to the straight round intakes with no cheaters. Weight rtf is comparable too, although the Su-35 has a lot more space for batteries.

In either case a lot of throttle management (just like the originals) leads to pretty good performance & reasonable flight times, due to the very low airframe weight.

.
Sep 09, 2018, 04:39 PM
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As a follow-up on the previous post, from my simple measurements ...

the installed fan static efficiency for the stock outrunner FW 12-bl in the FW Su-35 is around η=0.32 ...

On the other hand, the installed fan static efficiency for the CS-10bl + MT 2200kv inrunner in the FW Su-35 is around η=0.37 (see below).

As a comparison, the overall static fan efficiency in my Sukhoi Su-47 Berkut which uses two Cs-10 (ten baldes) with inrunners (M.T. from HK) is around η=0.42.

For the CS-12 (12 blade) fan with MT (HK) 2200 kv inrunner motor I measure it around η=0.38 installed in the Freewing Hawk (which has pretty good ducting).

As a last comparison, a freestanding WeMoTec evo 70mm fan with inrunner(Hacker E40L) and intake lip has η=0.56 (WeMo measurements).

So in part one is paying the price of ducting. That might be a big or small step depending on your perspective...
Last edited by Herb; Feb 24, 2019 at 03:14 PM.
Sep 18, 2018, 01:32 PM
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The Freewing Su-35 flies quite nicely with the two 12-bl Freewing outrunner fans, power is good at ~ 2600W and the sound is very pleasant.

The two fans seem to be reasonably well balanced, there's no weird resonance and the esc's handle the load well.

Nevertheless there have been repeated incidents at my field (at least two that I know of) where the very same Freewing outrunner motors burned up in the FW 70mm F-16, bringing the plane down and causing some bubbling in the fuselage.

They eventually both got a free replacement motor from MRC, but that took forever (one month) as that outrun. motor was not in stock. As a result they already had switched fan to an xrp when the replacement arrived.

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Sep 18, 2018, 01:38 PM
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As a preventive measure I decided therefore to switch out the whole power system to twin CS-10 blade fans with MT 2200kv inrunner motors and YEP 100A esc's ...

The new Watts are ~ 3240W at ~136A and installed thrust at round ~ 3.22 kg, giving an overall efficiency of around η=0.37 which is comparable to, but not quite, what I get in the LX Su-47 twin 70mm (η=0.42)

.
Last edited by Herb; Feb 24, 2019 at 03:13 PM.
Jan 03, 2019, 04:18 PM
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Video of the maiden ,

Su-35 Flanker by Freewing Maiden - Twin CS-10 70mm Inrunner Fans (3 min 54 sec)
Last edited by Herb; Jan 08, 2019 at 12:58 PM.
Mar 06, 2019, 07:41 PM
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The two FMS 70mm inrunner fans have arrived, so I should be able to test them soon in the Su-35.

Since I use the same connectors on all my fans, the fan swap should be very easy...

I put both fans on the test stand, and did some minor extra balancing (a small piece of red electrical tape inside the spinner).

.
May 28, 2019, 11:51 AM
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Another good - but very breezy - day at the field

15+mph winds kept most fliers at home, the Hobby Eagle A3 Super 3 v3 gyro worked hard and was very effective !

.
Jun 19, 2019, 12:35 PM
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Incidentally it turns out that the new FMS 70mm inrunner fans have what looks like the exact same rotor as the CS 12-bl fan ...

That explains why the FMS fans do as well as the CS 12-bl in mine, and why the WeMoTec minfans worked so poorly here when I tried them two years ago (too much turbulent air from those huge cheaters).

.
Nov 14, 2019, 12:48 PM
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E-Flite / FMS is coming out with a similar (70mm twin edf) Su-30 :

https://www.rcgroups.com/forums/show...&postcount=442

https://www.horizonhobby.com/su-30-t...tery-efl01050c

Flight characteristics should be similar to the Freewing Su-35, except for the fact that the FW Su-35 weights 2.5 to 3.5 kg rtf (depending on fans & batts) whereas the FMS one weighs 4.38 kg

https://www.motionrc.com/products/fr...mm-edf-jet-pnp

The difference is most likely due to the fact that the FW Su-35 is made out of styro (ie beercooler white foam) whereas the FMS one is EPO, which is a bit stronger but also quite a bit heavier.

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