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May 16, 2017, 11:47 AM
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Build Log

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.


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