Official Freewing MiG-29 Fulcrum Twin 80mm Thread

[GliderGuy]

For all the new recipients and soon to maiden, would be advise able to read back through this forum and pay attention to these topics:

- CG location
- Beefing up the elevator push rods
- RF Chokes
- Set-up
- Falling Leaf recovery
- Other lessons learned so far

Have Fun!

-GG

[Evan D]

Throws are a personal thing, as are expo. I have triple rates and fly with elevator and rudder on mid. I take off on aileron mid and flip to high after I get moving. I also have tailerons on my high aileron rate.

The better thing with the collar on the stab shaft is to see where the screw will tighten and grind a flat at that spot. I also use red loctite.

As noted stronger elevator pushrods are a good idea as well as stronger servos, and use the inner hole if you can get proper travel there. I also moved ailerons in a hole to get better mechanical advantage there. Also as noted you can maiden on the CG marks or 1/4" behind and then start moving your balance back as desired. Having steering on a seperate channel to be able to reduce it's movement and have separate centering is a good idea.

I hate a bunch of spaghettis wiring and put my receiver under the battery tray and the MCBe off to the side of the rear battery. I helped in getting a much neater battery area and made the center battery spot more usable.

[janmb]

I hate a bunch of spaghettis wiring and put my receiver under the battery tray and the MCBe off to the side of the rear battery. I helped in getting a much neater battery area and made the center battery spot more usable.

Big +1.

Putting in the extra effort when building to make everyday use clean and tidy is so worth it.

Usually, I would definitely gone rx under aft tray as well. In this particular case I have a slightly different approach though, using tiny satellite rxes up front (they weigh nothing), a cortex pro in the aft end of the front bay, and a Jeti Central Box 200 to the side of the aft battery bay. The Rxes and gyro are all communicating on serial bus, so just single leads running from rx through gyro and back to the CB, then sort the spaghetti there. Will also wire almost everything directly into the CB rather than the blue box. Will keep the BB, but pretty much for lights only.

[kallend]

I'd like to recommend a new burner on the market. (At least it's new to me.) I believe I've tried them all except Kallend's do-it-yourself kit.

Just to be clear, all I provide are details of how to do-it-yourself from readily available components (Amazon has everything you need). The details and firmware code are free, as are the STL files for 3D printing the necessary adapters. It isn't a 'kit" and I'm not attempting to sell anything.

If you're competent with a soldering iron and willing to invest about 2 hours of your time, you can make a 'flickering" system for a single for around $15, and for a twin for around $25.

[Raydar]

I realised due to posting here and at rcgroups I never updated on my tank fitment, well it was a bitch and although it fits it can be a bit brutal making it work. Found a video today of a guy flying with x45 and mig-29 and what looks to be the sullivan 32oz V tank, it looks to be simpler fit with perhaps less foam hacking though more fuel will be slightly further forward as its longer. https://www.youtube.com/watch?v=XdNK...OOla8ha5vglZcI

Mine is in though so job done.

[Raydar]

dup

[leithalweapon]

The problem is that the inner diameter is much too large, making the tube next to useless

Sure, it will prevent the rod from bending double, but it is still allowing bending equalling about half an inch travel at the taileron leading edge

Yep. All the tube does is prevent the rod from permanently bending and not returning to it's original shape, which is straight. Where I live we call that Tennesse engineeeing.

[janmb]

Yep. All the tube does is prevent the rod from permanently bending and not returning to it's original shape, which is straight. Where I live we call that Tennesse engineeeing.

My solution below....

Also replaced flap servos with Hitec D85MG and adjusted geometry to gear it as low as possible.

Honestly not surprised about the elevator issues. Did some manual testing today, and the force required to stall the stock setup is next to nothing. Even my upgrades, tested at 6V, 5.5 kg/cm torque, with identical geometry as the stock setup, takes surprisingly little effort to stall. Those elevator surfaces have a huge leverage, even with decent geometry.

[mshagg]

Is the D85 reference correct? I am using them but they only have one screw at each end.

Edit: disregard, I just saw you were referring to flap servos.

I'm eyeing off the D645MW for ~8.5kg @ 5v, which will require some carving to fit but is more than double the torque of the D85MG and only an extra $10AUD per side.

[janmb]

Is the D85 reference correct? I am using them but they only have one screw at each end.

Edit: disregard, I just saw you were referring to flap servos.

I'm eyeing off the D645MW for ~8.5kg @ 5v, which will require some carving to fit but is more than double the torque of the D85MG and only an extra $10AUD per side.

As long as you can make it fit, there is absolutely no downside to overdoing it for sure. I would do some homework on depth first though - the elevator servos don't have a huge deal of excess foam to remove before punching through the topside. I managed to get my 5245 in without too much carving, but any much deeper (taller) than that might be a challenge.

[mshagg]

As long as you can make it fit, there is absolutely no downside to overdoing it for sure. I would do some homework on depth first though - the elevator servos don't have a huge deal of excess foam to remove before punching through the topside. I managed to get my 5245 in without too much carving, but any much deeper (taller) than that might be a challenge.

Yes, good call - as you also run the risk of interfering with the vertical stab mount (I understand the assembly for the horizontal stab/vertical stab/elevator servo is all essentially one complete plastic 'box'). Measure twice grind once (ok maybe grind two or three times).

[Rcfiddy1]

Did my maiden today with setup as per manual. I felt it was nose heavy and carries a lot of speed due to weight. I flew with Zeee 5200 mah packs in the mid and back position. I needed to add a small 2 cell up front to achieve CoG as per manual so next time I will move it back a little. Also I fly on high rates and the roll rate seems a bit slow. Might try tailerons next mixed in. But she does look and fly pretty good with Hitec servos and linkage upgrade. 2:40 for mig.

[Evan D]

Congrats! I have my tailerons mixed 50% and I’m happy.

[mshagg]

OK, now to figure out how to make them do stuff...

[vduniec]

Sorry Kallend. I apologize for the incorrect statement. Although I haven’t had an opportunity to try your setup yet, I really do appreciate you taking the time to help others learn how to do it.

Just to be clear, all I provide are details of how to do-it-yourself from readily available components (Amazon has everything you need). The details and firmware code are free, as are the STL files for 3D printing the necessary adapters. It isn't a 'kit" and I'm not attempting to sell anything.

If you're competent with a soldering iron and willing to invest about 2 hours of your time, you can make a 'flickering" system for a single for around $15, and for a twin for around $25.

[mshagg]

Still need to seperate parts and try a test print (need to figure out the offset for hard point), but here's a WIP of a FAB M62 500lb bomb. Ill put it on thingiverse when it's done - not a lot of ordnance there for soviet jets

[gooniac33]

My solution below....

Also replaced flap servos with Hitec D85MG and adjusted geometry to gear it as low as possible.

Honestly not surprised about the elevator issues. Did some manual testing today, and the force required to stall the stock setup is next to nothing. Even my upgrades, tested at 6V, 5.5 kg/cm torque, with identical geometry as the stock setup, takes surprisingly little effort to stall. Those elevator surfaces have a huge leverage, even with decent geometry.

Before a maiden one of the things I always do it check the strength of the servo. If it doesn't meet my expectations then I change something before I fly it. Simple as that! I think that most people would still have their planes if they had checked this before flying. Once I get mine then even with the new servos in place I will still check to make sure that I have it set up in the way that will give the servo the most amount of torque. Last thing you want is a servo to stall at the bottom a pull at low altitude!!

Also the Mig-29 was the subject of my live stream last night! Take a look!!

[Evan D]

I posted how much force applied to the elevator would stall it, both stock and FW upgrade servo. 300g vs 400g.

[PaulZ]

Successful maiden! Here is a video of flight #4: https://youtu.be/CqV0Z66s-5k

One observation - there is certainly a non-linear response to the elevator, it feels awkward. I have the upgraded servos from MRC. I think it is due to the flex on the control rods. Even with the carbon fiber tubes the rods flex. Funny enough MRC sells rods for the F-14 Wing sweep mechanism that are perfect length and are much thicker. I'll be installing these soon: https://www.motionrc.com/products/fr...ng-pushrod-set

[janmb]

I posted how much force applied to the elevator would stall it, both stock and FW upgrade servo. 300g vs 400g.

Without having made similar measurements, definitely sounds about right.

I never tested the upgraded FW servos yet though, went straight to bigger stuff. And even that feels fairly weak tbh. Clearly more than 400g, but still would love to have more.

Might look into how much throw I can actually get if moving in one more hole.