Freewing Su-35 Twin 70mm 12 blade

[seaviper]

I will be putting in the F-15 main struts as soon as they come back in stock. The stock gear is doing great so far though. It's so easy to land slowly. I guess most of the gear damage occurs on takeoff.

Here is my final battery tray mod. Very secure battery with moderate pressure on the strap. The original was hard to cinch down.
The extra pieces of shelving liner were glued-in with Tacky Glue.


I found this post from another thread here at Hobby Squawk where someone melted EPS with Foam Tac.
https://www.hobbysquawk.com/forum/rc...9389#post49389

[xviper]

Yes, I use a small (1" wide) foam brush. It goes on a bit white, with visible streaks but as it dries, it gets clear and the streaks are very hard to see. When completely dry, you can't tell anything is on it except that slight sheen.

[seaviper]

My wife has mod podge. Im more interested in how it's applied. Do you just brush it on?

[xviper]

I don't think there's anything on a retract strut that the solvent in FoamTac can attack. I also took apart my canopy to reattach the little pilot (didn't have a cartoon to put in there) and used FoamTac to glue the guy back in and to glue the canopy back on. I just checked and it's been over an hour and it didn't eat anything. Your report is the very first one I've heard of FoamTac doing anything nasty like that. I've used it quite liberally on other models made of the same foam and those didn't have any bad results either. Now, "Welders glue" .................. that stuff I know for a fact will eat and dissolve foam and on certain types of foam planes, they want you to use it for that reason. The Twisted Hobbies EPP planes specifically say to use that type of glue.
I've done many planes in Mod Podge. It does give a nice protective layer and a kind of sheen to it. Here is a picture of my last Mod Podged plane. It's the Ozzy theme Freewing F/A-18, 90mm. The SU-35 and F/A-18 are both made of EPS foam, so the SU should turn out very similar to the 18. I also used FoamTac to put together the F-18.

Here's the Mod Podge (can be bought at Michael's) ................................ https://www.amazon.ca/Mod-Podge-Wate...45395944&psc=1

[seaviper]

Interested to see how the mod podge turns out.

[seaviper]

Be careful with the foam tac. I melted some stuff with it.

I use Gel Tacky Glue for that long wire cover on bottom of fuselage. Thought about several ways to make it removeable. Right now the glue is my best option.

Can't wait to see some video of the bird.

[xviper]

I'll be using a gyro for those times when I want to play around with hovering. Flaperons won't work with a gyro.
I've inspected and tested all the parts. All servos work as they should. Bound it up to do the throttle calibration and make sure the motors are spinning in the right direction. Will start with the Mod Podge when the weather turns crappy again. I've already embedded a CF square inside that nose strut brace, then reinforce the crap out of that nose retract. My last SU-35 showed that the main struts came loose quite easily bouncing along that rough terrain. I'll go in and put some FoamTac on as many of the grub screws as I can reach without taking the things out of the plane. The rest, I'll deal with as they become known to me. Hopefully, there won't be too many.

[seaviper]

Nice! great video! Yours looks like it flies similar to mine. I love the way she lands. Good job.


Good luck on the build. She is a great jet. Just go in and fix a few things first.

I did not have to shim the nose wheel. Just used some epoxy. She flew great on cut grass yesterday.

My battery strap decided to start coming loose after 6 flights though.
So I made some new parts, dug up a T-45 battery strap and voilla. One strapped battery. And you don't even have to tighten it much, which puts less stress on the battery bay.

Oh and I did a lot re-programming. I have it where when flaps go down, ailerons are gone, but tailerons are active. This will work well based on my flights yesterday.

[xviper]

MIne just came. Unpacked it to do a cursory inspection. All seems present and accounted for. The little pilot came unglued. I guess if I'm going have take the canopy apart, I'll put in a cartoon character instead. I had forgotten just how big this plane is, even by today's examples. Next, I'll test all the servos and retracts before Mod Podging it prior to assembly. Maybe I'll get to maiden it before the snow comes for good.
I dug up an old video from 6 years ago of my second flight of my first SU-35. It flew quite well and if not for the Deans plugs melting and fusing together, I may still have it flying today.

[seaviper]

I took off that aluminum foil from the wire harness and just put a piece of aluminum tape between the two esc's to kind of insulate the harness.

[seaviper]

Three more flights on her today. Nose gear did fine. Hit 107 mph according to the airspeed sensor. A lot of fun.

I did trim the screws that secure the fan hatches. I cut off three threads on each to keep them from protruding into the duct and catching grass.

The ESC's get hot for my taste. But I think they are OK. Today they were running about 140F in the air and 160 on the ground parked. That's about 20F cooler than before I did the mods. OAT was about the same at 90F.

Still experimenting with flaperons. I may just program her such that when flaps are selected, ailerons are locked out and tailerons take over. I flew one approach today with flaperons and tailerons. She slows down nicely with good roll control. But I had too much up-elevator mix for the flaps. I need to dial that in. I think the final values will be maybe 3% and 5% for 1/2 and full flaps.

With flaperons engaged, at either 1/2 flap or full flap, the ailerons felt very sluggish and non-linear. So I engaged tailerons and everything went back to happy again. I did takeoffs with 1/2 flaps and also with no flaps but with TV on. No difference in my book. If using TV on takeoff keep your hands off the rudder. Otherwise you will have a wild ride

More test flights on Friday.

[xviper]

The fans were soooo dirty. Got them cleaned too.

That's one thing I remember about my first one. The front tire is just in the worst place for kicking up stuff and right into the intakes. My first one flew off a gravel runway. The fan blades got dinged up really bad even after the maiden.

[seaviper]

I went and trimmed some heat shrink off the stock esc's and lined the bay with aluminum tape. I also added some emergency heat protection in the form of a foil wrap on the flight control wires passing through the esc bay.



Nosewheel is fixed. I decided not to shim it. I just gave it a proper gluing and replaced the scale brace.



The fans were soooo dirty. Got them cleaned too.

"Volkhova" is back on duty.....

[seaviper]

Well the grass is cut every week. This day it had been 6 days since the last cut. It was ridiculous to fly in that grass. But I wanted to test her out.

She did take a long time. The first flight she got off much quicker because I had TV and flaperons (1/2 flaps). On subsequent launches I did not use flaps. She really likes flaps on takeoff in grass.

I did check the mains. They seemed good. Today I am going to build a plywood plate to mount the nose gear and steering servo on.

I forgot to mention that I did all those flights at a CG of 155mm. I started out with elevators at 11mm as per the book (10-13). I ended up putting a half turn of up elevator on each clevis. So I am probably running like 13mm now.


My battery placement. I also have a pitot sensor in the nose, two receivers, and other sensors ahead of the CG. With this heavy Turnigy HD 5000, I balanced at 155.



Currently I am shimming the nose gear and steering servo, cutting away heat shrink from the stock esc's, and lining the esc compartment with aluminum tape. I may go ahead and order some YEP 80's. I don't know. More than likely, I will fly these again to see if the temps are better.

[xviper]

Bummer about the nose gear. Those weren't even hard landings. You have very plush grass. My field grass is not nearly as plush but it is very bumpy. I think I'll take out that nose gear and build in wood blocks to mount the whole assembly. I'll also reinforce that "leg brace" with CF strips on each side. My first SU also had this problem. How did the mains hold up? I may take a close look at those as well.
The Phantom also looked like it took a long distance to get off that grass.

[seaviper]

Yesterday I flew three flights with the Su-35.

Stock 12 bladed power system
Turnigy Heavy Duty 6s 5000 all three flights, pushed all the way forward
Flight controls at 40% expo
Nose wheel steering at 75% expo (really gentle in the middle, but I have full throw for turning around)
Taranis X9D Plus SE
Dual X8R receivers


Weather:
91F
High humidity
Week old uncut Bahia grass (not optimal for this bird)

ESC temps shown below are after landing with no airflow. Temps climbed about 20-30F after the bird was stopped on the deck.
In-flight temps were about 135-150 F.

Flight 1 duration 4:44 due to trimming and go-arounds, not a recommended practice

Flight 2 duration 4:04 formation flight with F-4

Flight 3 duration 2:47 formation flight with F-4


Observations:

1. Stock power is really good. More than enough.
2. Thrust vectoring is just a non-issue. The bird flies fine both fast and slow with TV on. I will leave it on all the time.
Freewing provides handy alignment marks on the gimbals. Use them and there will be no problem with bad thrust lines.
3. I tried takeoffs both with and without flaperons; And with and without TV. It likes TV and flaperons in high grass.
Just be aware there may be a slight asymmetric throw with ailerons. Dial this out or you will have roll with flaps. not good.
Flaperons require a healthy dose up-elevator mix. Further flights will show how much.
4. Rudder brakes worked nicely. Because I didn't use flaps due to asymmetric throw and because I had to come in over the tree line, I had to deploy brakes to get down. There were no adverse affects. And they work.
5. Tailerons. I used them fast and slow. I did not like the corkscrew effect. They might be useful on some 3D maneuvers.
6. Flight times are about 3 minutes at high throttle on a 5000.
7. The nose gear mount is not glued very well. I had no hard landings yesterday. All three were greasers. My nose gear still came unglued.
I recommend just going ahead and re-gluing the nose gear and doing the shim mod while in the process. I will do that today hopefully.
The only damage from this was some chipped foam in the wheel bay, a broken plastic support arm for the nose gear, and a broken steering clevis. I also got a little dirt in the pitot tube.


Nose Wheel Collapse

8. It fits in a Jeep Patriot in one piece. I couldn't take my wing apart anyway due to the lighting system. And my nose cone is glued on with a spear (er pitot) on the end.

Now I know why people love this plane. She flies really fast, sounds great, looks great, and also flies some insane maneuvers. On flight three, I did a hover and a back flip. She used a little altitude getting her flying speed back. Crashing an Su-35 is not hard to do. But the aerobatics are just too much fun. That thrust vectoring and the Leading Edge Root Extensions (LERX) , aka "wing root glove", just begs you to pull the nose up and kick the rudder boy...lol. Just make sure you have some alt.

[seaviper]

Maiden flight

See post below

[xviper]

I think those 60A ESCs are a bit on the marginal size and they will run a bit warm. Even my 4s Mig-29 runs bigger ESCs and those are exposed to outside air and still come down warm.

[seaviper]

I will have my wife filming with the Canon. I will upload tonight if we fly. My buddy just re-painted his F-4 in snow camo. So this will be first flights on both.

I calculate less than one half of one percent difference. Can't hear it. Actually that could be a difference in the sensors themselves.

I was reading on the Hobbywing site and got confusing numbers on esc temp. I expect these to be hotter than normal as they are not in the direct flow to the fan and there are two of them right there together. I'm just wondering what I should consider as a baseline for them.

I'm just guessing that 130F might be expected. Temp here is in the 90'sF.

[seaviper]

I'm thinking I will name her Volkhova, the daughter of the sea king in Russian mythology.