Official Freewing MiG-29 Fulcrum Twin 80mm Thread

[Airguardian]

[barneyb]

Thanks crxmanpat ... so I am well within limits at 5.3v (good to know).

GG,
In my case increasing the voltage increase (from 5.1 to 5.3v) fixed the servo chatter & automatic deflection of control surfaces that I was experiencing. I do have a choke on Bec cable but it seems my issue might not be related to interference else increasing output voltage from BEC (going to receiver and blue box) won't have fixed it (everything else being equal).

Gents I used an old school solution to driving the horizontal stabs with digital servos at 7. volts. I used a JR Matchbox. So only the stab servos see the higher voltage. Used a small 2s lipo regulated by a YEP regulator to 7 volts. Works great the Matchbox lets you reverse servos so there no searching for a reverse servo. The FW regulator doesnt have the extra load of the stab servos. Unfortunately the JR Matchbox isn't made anymore.
Mig is an awesome flyer. Easy as pie.

[Birdseed]

I posted back in post 5256 about my weird diving behaviour.
I posted vid of it on YouTube as per the link below.

I finally think i found the problem. I just test flew it today and the ac was on rails.

I think it was a gyro issue. I was settting up another model (a FW F22) and spotted one elevator acting as an elevator in response to the gyro, and the other elevator acting as an elevon!

Turns out my mig 29 is set up the same way and when i checked it, the exact same thing was happening.
I’m using a powerbox igyro sat.
For anyone not using one, it will be incredibly boring for you to continue reading…..

Id set up each elevator to Elevator A and Elevator B.
I set up one aileron channel to Aileron A

Turns out if you want a delta mix with a igyro you assign one elevon to AILERON A and the other to ELEVATOR A.

As a result one elevator (elevator B) receives a gyro input as an elevator, but the other acts as an elevon.
To make it worse, the aileron A (the single aileron channel feeding both aileron servos) would have been acting as an elevon when the gyro was active.

It’s basically an anomaly in the programming when you have two elevators and a single channel feeding both ailerons.

Problem is solved by assigning Aileron B to any of the other 26 unused channels and it works.

I had one flight today and it flew great. As the airframe is now “proven” i can start my X45 conversion.

[Ironside]

My Top Design struts and brakes showed up too. Nice stuff except for the stiff springs. Same as yours. I can barely compress the strut springs. They will probably barely compress with a hard slam down landing. I can't imagine why they are so stiff. We will see. I have not installed them yet.

I just got my Top Design struts and just as everyone has stated, these things are way too stiff. I mean I have to really push on them to get them to compress. Did anyone ever find a replacement spring or mod the strut in any way for more compression/cushion?

[jasmith41]

Thanks GG - i ordered more of the 9mm core diam ones, so i'll pop the 2 smaller ones off and put the one big one over both lines... i got an assortment originally, but used up all of the 9mm ones already. some of the planes already have what looks like an rf choke on their batt lines, so i'm leaving them alone...

[GliderGuy]

since i'm out of the bigger chokes, is there any reason i can't put one smaller one on each battery line...?

That works, too. Of course, maybe not quite as effective, but in my opinion you are still ahead of the game just by using them.

-GG

[jasmith41]

Thanks, but I was hoping for something more specific than a range from 3mm to 13mm, most of which would be redundant.

the next size down from the 11mm seems to work perfectly on the battery line in my 6s planes... not sure what wire gauge they are - sorry...

[jasmith41]

I have had several Eflite planes and I recall that on a couple of them, rather than using those green rings (like wedding rings), they use those "chokes" on the throttle lead. Even when using those chokes, they wrapped the lead in and out of the choke several times just like on the green rings.

since i'm out of the bigger chokes, is there any reason i can't put one smaller one on each battery line...?

[kallend]

Problem solved: it was the castle creations 10amp bec … moving back to stock bec solved the issue.

Thank you Evan & GG for your suggestions.

I've been building electric airplanes and helis since before it was fashionable (1980s) and have not had the greatest luck with Castle's creations. Not as bad as Detrum, mind you, 100% failure rate with those. I've never had a Hobbywing give any trouble.

[Luqman Khan]

Problem solved: it was the castle creations 10amp bec … moving back to stock bec solved the issue.

Thank you Evan & GG for your suggestions.

Many thanks for sharing your experience - i guess I'll have to start with process of elimination as you suggested.

Its good that i'm able to easily reproduce the issue on bench so I'll know for sure when it works.

[kallend]

OK, thanks, guys. Chokes on order.


Incidentally, it's not for a MiG. I'm using the PWM feature of an Arduino to drive a high power LED and want to avoid noise on the power line feeding back into the Rx.

[xviper]

I have had several Eflite planes and I recall that on a couple of them, rather than using those green rings (like wedding rings), they use those "chokes" on the throttle lead. Even when using those chokes, they wrapped the lead in and out of the choke several times just like on the green rings.

[GliderGuy]

Thanks, but I was hoping for something more specific than a range from 3mm to 13mm, most of which would be redundant.

You will use 2 of the 13 mm near the ESC body. Then I added a 3 or 5 mm by each FFS servo…not much room back there.

I ordered a multi-pak and have dipped into it on several occasions…and will again when my PJ50 gets here. Handy to have redundantly on hand.

-GG

[kallend]

Amazon.com: Ceedmon 20 Pieces Clip-on Ferrite Ring Core RFI EMI Noise Suppressor Cable Clip for 3mm/5mm/7mm/9mm/13mm Diameter Cable, Black : Industrial & Scientific

EDIT: Site (or my browser) went berserk and posted same thing 3 times.

[kallend]

Amazon.com: Ceedmon 20 Pieces Clip-on Ferrite Ring Core RFI EMI Noise Suppressor Cable Clip for 3mm/5mm/7mm/9mm/13mm Diameter Cable, Black : Industrial & Scientific

Thanks, but I was hoping for something more specific than a range from 3mm to 13mm, most of which would be redundant.

[jasmith41]

To those (GG?) who have put ferrite rings on the long servo leads, do you have a link to a source?

Amazon.com: Ceedmon 20 Pieces Clip-on Ferrite Ring Core RFI EMI Noise Suppressor Cable Clip for 3mm/5mm/7mm/9mm/13mm Diameter Cable, Black : Industrial & Scientific

[kallend]

To those (GG?) who have put ferrite rings on the long servo leads, do you have a link to a source?

[Evan D]

Pretty sure people have posted it before in both this and the RCG thread.

[Ironside]

Anyone know the total thrust (in newtons and/or lbs) the Mig 29 is pushing on two 6S batteries?

[Luqman Khan]

Many thanks for sharing your experience - i guess I'll have to start with process of elimination as you suggested.

Its good that i'm able to easily reproduce the issue on bench so I'll know for sure when it works.

In MY experience what you are describing is normally caused by feedback in the servo leads caused by resistance. Normally a bad connection at an extension connection or something similar. Remember the MCBe is basically a bunch of Y connectors. I think when you increase the supply voltage it’s pushing through this extra resistance causing the feed back.

What you need to do is track down the source of the resistance and correct or eliminate it. It may be dirty connections, bad solder joints in the MCBe, servo wires that are close to other wires (the chokes are a great fix if this is the cause but also twisting the servo wires can help if this is the issue ), or what ever.

The thing is that you still have an issue even though you are reducing the symptoms by increasing the voltage. If it was me I would bypass the MCBe with standard extensions and Y’s as a first step.