Official Freewing MiG-29 Fulcrum Twin 80mm Thread

[GliderGuy]

Congrats radfordc for the comeback! ;)

Update: I am almost done repairing my MiG-29 after my later crash, and this time I'm adding the TV nozzles, so expect some interesting stuff coming up soon on my end! ^^
(Though I still have a few unvectored videos to publish! ;) )

The crash / What happened?….If you don’t mind sharing.

Your inverted high alpha flying looks impressive!

-GG

[Airguardian]

Congrats radfordc for the comeback! ;)

Update: I am almost done repairing my MiG-29 after my later crash, and this time I'm adding the TV nozzles, so expect some interesting stuff coming up soon on my end! ^^
(Though I still have a few unvectored videos to publish! ;) )

[jasmith41]

I flew my new Mig today. I don't mind saying I was a little nervous after destroying one last year. Three good flights with no squawks.

You have bigger balls than me thus far. I still haven't even flown my EF SU-30 i bought and built a year ago, let alone unbox the Mig-29 I have...🤣🤣🤣
And now i'm thinking i need the FW SU-35 to learn on...

[Evan D]

Congrats!

[radfordc]

I flew my new Mig today. I don't mind saying I was a little nervous after destroying one last year. Three good flights with no squawks.

[jasmith41]

Mine is about 5mm behind the marks but sometimes I do 10mm. I do have the full span reflex in mine and TVs. Before the reflex and TVs I was a little further aft, 10-15mm behind the mark.

Thanks man...

[Evan D]

Mine is about 5mm behind the marks but sometimes I do 10mm. I do have the full span reflex in mine and TVs. Before the reflex and TVs I was a little further aft, 10-15mm behind the mark.

[jasmith41]

There is no golden rule of thumb but most manufacturers tend to recommend overly nose heavy setups.
The way to go is through in-flight testing to determine whether a CG is too far forward or aft and converge on a more neutral spot (accounting for pilot preferences, obviously).

Thankfully for you, this jet has been tested thoroughly by many people in this thread and others, and mostly everyone will agree and recommend to set the CG 15mm behind the factory-molded CG marks on the wings. Not any forward, not any further aft.
Fwd of that is too nose heavy, and aft of that the plane's capability to recover from a high alpha lock without help of thrust vectoring nozzles diminishes substantially.

If you are using vectored nozzles, then you should be fine to experiment beyond 20mm aft of the CG molded marks without much trouble (always doing so with common sense, in incremental steps and following a sound method, of course).

Thank you...! Seems most lean back on CG from book rates...

[Airguardian]

There is no golden rule of thumb but most manufacturers tend to recommend overly nose heavy setups.
The way to go is through in-flight testing to determine whether a CG is too far forward or aft and converge on a more neutral spot (accounting for pilot preferences, obviously).

Thankfully for you, this jet has been tested thoroughly by many people in this thread and others, and mostly everyone will agree and recommend to set the CG 15mm behind the factory-molded CG marks on the wings. Not any forward, not any further aft.
Fwd of that is too nose heavy, and aft of that the plane's capability to recover from a high alpha lock without help of thrust vectoring nozzles diminishes substantially.

If you are using vectored nozzles, then you should be fine to experiment beyond 20mm aft of the CG molded marks without much trouble (always doing so with common sense, in incremental steps and following a sound method, of course).

[jasmith41]

Time for some more Fulcrum shenanigans!

Great vid - mine is still in box in office. I may actually buy and fly their SU35 before the 29...

What's your general rule of thumb on CG? Do you always go by the book, back a bit, forward a bit, depends on the jet, etc....?

[Airguardian]

Time for some more Fulcrum shenanigans!

[GliderGuy]

Here is a question. I see this Mig29 reguires two 6s batteries. Are these batteries connected parallel or series? I am thing they are connected in parallel and is set up for 22 2 volts. Am I correct?

Actually….Neither.

The MiG-29 has two “systems” totally separate. One battery drives one ESC/motor and the BEC. While the other battery drives the second ESC/motor only.

The + of one battery never sees the + of the other battery. Ditto for the - battery terminals.

I have my P-38 systems wired in parallel. When one battery Is connected ALL systems become alive….both ESCs, and the BEC. When I connect the second battery….nothing more becomes live. The + of both batteries now “see” each other. Ditto for the - terminals. I did this because the P-38 instantly and violently rolls when one motor fails. Now wired in parallel, EITHER battery can keep both props turning.

Now you COULD wire the MiG-29 like I wired my P-38. But why? The MiG-29 won’t violently roll if just one motor stops. A parallel wired MiG-29 would, however, keep ALL systems working if the critical (BEC) battery started to sag.

So what if the MiG-29 battery powering the BEC+motor sags? If the voltage gets low enough, you may have your hands full. In this respect, physically wiring the MiG-29 in parallel does add a measure of security. The decision is up to you!

One IMPORTANT note….flight times don’t change just because you decide to make the batteries parallel in the case of the MiG-29 or P-38. The total system before wiring in parallel is: 2 motors, 2 ESCs, BEC, and the loads on the BEC AND 2 batteries. After you do the wiring, the total system DOES NOT change.

Now take an AL37 (one battery driving everything) and wire in a SECOND battery in parallel, you will dramatically increase your flight time. But notice, you CHANGED the system. You went from one battery to two.

And some use a separate battery just for the BEC+ its loads. It’s not connected to anything but the BEC. Now you don’t depend on a heavily loaded flight battery to power the BEC and its loads = added security. Note: Read your radio manuals...some provide additional guidance for implementing this set-up specifically for their radio.

-GG

[xviper]

Hint: This is a 6s power system. Hooked up in series, it would be a 12s system.

[Falcon195]

Here is a question. I see this Mig29 reguires two 6s batteries. Are these batteries connected parallel or series? I am thing they are connected in parallel and is set up for 22 2 volts. Am I correct?

[radfordc]

I can see how it helps tie the gear into the two plastic wing retainer mounts. Good idea.

[GliderGuy]

Like so.

perfect!

[radfordc]

Like so.

[GliderGuy]

Are there pictures of what you did to reinforce the gear mounts? I'm starting putting a Mig together. Better to do the fix now than after the gear are loose.

For starters....here's the start of the posts about the plastic gear mount replacement process for your files and future reference. What a pain! The photo shows the mount area after you get the plastic mount out. WHAT A PAIN THAT WAS! it doesn't leave the area looking very pretty, either. But, this can be filled/repainted after the grunt work is finished and the new plastic mount installed. MRC support said, "The plastic mounts were not meant to be replaced."

https://www.hobbysquawk.com/forum/rc...385#post332385

PLEASE NOTE: YOU DO NOT NEED TO REMOVE THE PLASTIC MOUNT TO REINFORCE THE AREA!

I just happened to take the photo when I was doing the plastic mount replacement.

Now to answer your question: Primarily, the thin foam shelf on the outside (the side towards the wing tip) of the hole that the plastic gear mount sets in gets soft and mushy after a time.

Note: For the rest of my post, consider the MiG is upside down as in the photo. I wasn't concerned about how "pretty' this all looked because it is covered by the wing, once you put the wing on.

With the wing off, you will note on the fuselage there is an area of foam below (towards the floor) the thin outside edge of the plastic gear mount. If you carefully cut (watch for wires, spars, etc.) a notch into this foam and insert some carbon "under" the area of the outside thin shelf, it will strengthen this area significantly. It holds up REALLY well.

Glue in the carbon with your adhesive of choice, Foam Tac, epoxy, hot glue, etc. Whatever you think is best. I used JB Kwik Weld epoxy which has a 3000 psi strength. Slow cure epoxy will be even stronger.

-GG

Aside: Since one must cut the mount's 3 screws off with a Dremel tool to get the plastic mount out piecemeal (you gotta cut it out in small pieces), when I reset the new mount in the hole, I used epoxy to secure the plastic box and basically replace the function of the screws. Hundreds of landings later....the mount remains solidly attached.

PS: The reason the vertical wall is white is I glued some carbon sheet to this wall and then made an angle brace from the carbon sheet to the plastic mount. It turns out that this vertical wall is VERY thin and will tear easily when the carbon sheet is removed or the carbon sheet shears from a hard landing. In hind site, I don't think I would try attaching anything to this thin wall of foam that might put stress on the thin wall. It is not made to withstand any stress. It's only purpose is to form the wall of the air duct to the EDF fan. Lesson learned.....

[radfordc]

I also found that toe out can be a symptom of the main’s plastic mounting box becoming loose and/or the foam supporting the box becoming mushy.

A bit of carbon added in strategic places (remove the wing) around the plastic mounts works wonders.

-GG

Are there pictures of what you did to reinforce the gear mounts? I'm starting putting a Mig together. Better to do the fix now than after the gear are loose.

[GliderGuy]

Skosh25….here is the post

https://www.hobbysquawk.com/forum/rc-airplanes/rc-military-jets/267078-official-freewing-mig-29-fulcrum-twin-80mm-thread?p=326364#post326364

-GG