Official Freewing MiG-29 Fulcrum Twin 80mm Thread

[HK111]

Based on prior posts, I decided to upgrade to the MKS HV69 high torque servos. Mainly because they are an exact dimension match and with higher torque at 4.8V than the MRC upgrades. They also are spec’d to function down to 2.7V in case the voltage gets low in the tail.

To avoid just reversing one of the servos, one could also use the elevators as tailerons. It looks very cool, and as I have learned from other posters, apparently really flies well. That would justify using two channels.

Regarding the flaps: If one eliminates the blue box, one could also consider full-width flaps, using the ailerons as flaperons. Of course, not with enormous travel, but still. I assume it would also look cool :-).

Regarding reversers: My impression is that the newer generation of digital reversers are high quality and present no risk anymore. Nice. There are also short, high-q V-cables which contain a programmable reverser for one of the two outputs ("DPSI V-Match"). So you don't even need two extra parts (V-cable and reverser), but one.

Cheers,
Henrik

[HK111]

(and i have less throw than some others)

Did you consider upgrading the tail servos beyond the FW exchanged servos, in order to regain more throw (AFAIK you are currently using the innermost hole on the servo tail)?

Tx and cheers,
Henrik

[janmb]

To avoid just reversing one of the servos, one could also use the elevators as tailerons. It looks very cool, and as I have learned from other posters, apparently really flies well. That would justify using two channels.

Not just cool, and not just flies well. I would go so far as to claim the advantage being so huge that it should be considered almost mandatory. In short, those who fly modern FFS jets without tailerons are really missing out.

I find it a bit hilarious that FW/MRC generally shy away from taileron setups (to save channels I presume) where this is both scale and awesome, but on the other hand goes overboard with rolling canards on the Gripen - which despite looking fancy is neither scale nor beneficial in terms of flight characteristics.

[Airguardian]

Not just cool, and not just flies well. I would go so far as to claim the advantage being so huge that it should be considered almost mandatory. In short, those who fly modern FFS jets without tailerons are really missing out.

I would go even further and deem 'blasphemous heretical offenders' those that fly such jets without tailerons.
The Gods are ashamed of you.

But you can easily remedy that, convert today, redeem yourselves!
Absolution is within reach, take the right choice and make your ancestors proud!

[Evan D]

His real problem is using a 6ch radio, without more channels he is really limited...


The tailerons work awesome on this.

Full span flaps are cool but totally not need as well as this plane lands. It does need elevator comp (up) if you use it.

To avoid just reversing one of the servos, one could also use the elevators as tailerons. It looks very cool, and as I have learned from other posters, apparently really flies well. That would justify using two channels.

Regarding the flaps: If one eliminates the blue box, one could also consider full-width flaps, using the ailerons as flaperons. Of course, not with enormous travel, but still. I assume it would also look cool :-).

Regarding reversers: My impression is that the newer generation of digital reversers are high quality and present no risk anymore. Nice. There are also short, high-q V-cables which contain a programmable reverser for one of the two outputs ("DPSI V-Match"). So you don't even need two extra parts (V-cable and reverser), but one.

Cheers,
Henrik

[GliderGuy]

Sigh.....Maybe Santa is listening?

[HK111]

Hello,

for completeness, this is the V-cable+programmable reverser that I use. You have very little power loss, as the "switch" of the V-cable is a circuit board. Plus you can program the direction, the mid point and some more for one of the two channels of the V. Programming is initiated with the red "programming magnet", also on the picture. Good enough for me.

Cheers,
Henrik

[Mr.Stang]

Based on prior posts, I decided to upgrade to the MKS HV69 high torque servos. Mainly because they are an exact dimension match and with higher torque at 4.8V than the MRC upgrades. They also are spec’d to function down to 2.7V in case the voltage gets low in the tail. Torque Spec is 6kg-cm at 4.8V.

I decided against manually re-wiring one HV69 servo to reverse it, so I also ordered a Futaba SR-10 servo reverser (I have a 6 ch Futaba TX/RX). Some have suggested against reversers, some say “no issues”. The SR-10 was more expensive than the el cheapo reversers, and I have had good luck with Futaba for like....forever.

The HV69 servos have a 25 tooth 6 mm output spline but a smaller servo arm screw and thinner servo arm. The servo arm from the MRC upgrades won’t fit on the HV69. MKS does make an aluminum arm option which I will order.

Bottom line, I took out the one positive MRC upgrade servo and the upgrade MRC servo which I had to manually rewire/reverse because my upgrade kit had 2 positive servos in it. AND....I added a reverser + increased the torque and also got a lower min voltage spec for functionality. I am more comfortable, now.

Still am not gonna put flaps down at high speed!

-GG

EDIT: Correction min working voltage is 3.8V not 2.7V as originally stated.

Hello GG

They Servoarm from the FW Upgradeservos fits perfekt on the MKS HV69😉

Fred

[GliderGuy]

Thanks Fred....For some reason, I could not make it fit. I will take another look at it. I hope it does because the servo horn that came with the new servos is less robust.

The HV69 is a 25T 6 mm output spline for those reading.

-GG

How about that! It is a TIGHT fit....took quite a bit of pressure, but they do fit! Thank you! I’m much happier now.

[Mr.Stang]

Thanks Fred....For some reason, I could not make it fit. I will take another look at it. I hope it does because the servo horn that came with the new servos is less robust.

The HV69 is a 25T 6 mm output spline for those reading.

-GG

How about that! It is a TIGHT fit....took quite a bit of pressure, but they do fit! Thank you! I’m much happier now.

I was very exited about the Horn fits in the Servo
I was also happy about that 💪
Wish you allways good Flights👍

Fred

[themudduck]

Hmm, so two of those HV69 servos will set me back about $110 plus I have to get a reverser, and maybe pay shipping costs (depending on the vendor). About 20% of the cost of this model.
.
How much more power do the Motion upgrade servos put out if you're using the inner hole? In theory wouldn't that extra torque capacity mean that the servos won't be working as hard, and will be less likely to overheat/stall/draw too many volts and then stall?
I plan to use the inner hole (I was using the middle hole, which is the outer hole on those snipped control arms) and increase the throw to 125% on the radio. Thoughts?

[Evan D]

I put all the numbers in this or the RCG thread. The servo makes a specific torque, that does not change. But moving it in a hole it can provide more force but moves a smaller distance. I think it was about a 40% increase in applied force. Another important thing is the angle between the servo arm and pushrod. You want it at 90deg. You do not want the arm 90deg to the fuselage, as the manual says, you want it 90deg to the pushrod.

Once you do this then adjust the radio to get the manual throws. I didn't need much, it was still close to 100%.

As many have said this plus a better pushrod and a couple mm of reflex and the MiG is flying great.

[mshagg]

Just rewired mine to have seperate channels for each ele/ail servo. Any tips for how much pitch/roll mixing on the tail? Do you also reduce throws on the ailerons or is the idea here to get the thing spinning like a drill bit?

[GliderGuy]

Hmm, so two of those HV69 servos will set me back about $110 plus I have to get a reverser, and maybe pay shipping costs (depending on the vendor). About 20% of the cost of this model.

I wasn’t having any issues with the MRC upgrade servos (probably 300+ flights on them). But I could not shake from my mind Firebird’s loading / testing results showing the voltage getting down to 4V at the tail servos.

When I saw that the HV69 servos have a working voltage spec down to 3.8V, that’s what made up my mind to order them.

That’s the only reason I spent the $$$. Otherwise, I would not have spent the money. The upgrade MRC servos did all that I expected from them.

Each will need to weigh the options and decide. I am more comfortable with the added margin....decided to spend the $$$.

I added a potential point of failure with the reverser, but I removed one, too....my hand rewired servo (to reverse it). How good was my soldering job in tight spaces?

-GG

[Evan D]

I think I have 50%. Just use low rates if it rolls too fast..

Just rewired mine to have seperate channels for each ele/ail servo. Any tips for how much pitch/roll mixing on the tail? Do you also reduce throws on the ailerons or is the idea here to get the thing spinning like a drill bit?

[HaroldAnderson]

I put all the numbers in this or the RCG thread. The servo makes a specific torque, that does not change. But moving it in a hole it can provide more force but moves a smaller distance. I think it was about a 40% increase in applied force. Another important thing is the angle between the servo arm and pushrod. You want it at 90deg. You do not want the arm 90deg to the fuselage, as the manual says, you want it 90deg to the pushrod.

Once you do this then adjust the radio to get the manual throws. I didn't need much, it was still close to 100%.

As many have said this plus a better pushrod and a couple mm of reflex and the MiG is flying great.

Same here. Upgraded FW servos in the inner hole of the horn. I adjusted the horn to line up for the best throw. Added carbon fiber rods for spacers inside the carbon fiber of the stock pushrods and it has been flying great. 42 flights to date and I'll be putting 6 more on it in the morning. :-)

[Nero]

Please please please! I've been trying to get the centerline tank you have for fuel printed because I don't have a 3d printer. I keep reaching out via PM but no response from the creator. Can you get ahold of him got me?

-Thanks

This must be the file, get someone close to you to print it.

https://www.thingiverse.com/thing:4651488/files

[GliderGuy]

Follow up report - Several flights made with the MKS HV69 tail servos this morning. All went well. They are so quiet you almost have to visually confirm movement during the pre-take off checks (not that a visual check isn’t required for assurance).

it was comforting to have a more confident feeling of security.

As a side note and for you pilots with 6 ch radios, the trimmer on the Futaba SR-10 reverser appears to be temperature stable. It allows you to trim the reverse servo. I set it up at room temperature then it chilled in the truck all night.

When I fired it all up in the chill of sunrise after cold soaking all night, there was no change in the trim setting. Futaba states, “ Use of a precision internal power supply and temperature compensation circuit makes circuit operation stable as the temperature changes.”

-GG

[Borat]

Quick update for everyone. I had previously posted flight condition that leads to loss of elevator control and followed up with picture of the bent stabs just prior to crash. I have been working with MRC, providing them with information about the crash. This information was also sent to FW as well. I received a call from MRC yesterday and offered multiple options for compensation. They were all good. I was told that the production for this model has been stopped until FW does a thorough investigation to come up with a solution. My opinion is that this airplane flies just fine as long as you don't find yourself in a situation where you have flaps deployed, even if partial, nose down attitude while you advance the throttle. A clear example would be if you have to go around while attempting to land for whatever reason. Does this explain all crashes? Probably not. My goal was to find out why some of these Migs were crashing in a very similar way at a time when there was no clear explanation. To that extent, what I did and others who provided video evidence were able to show at least one condition where you could lose the plane. What's important is that MRC and FW listened and they took action-big credit to them. I look forward to seeing a better version of this Mig 29 take to the skies hopefully in the near future

[xviper]

What's important is that MRC and FW listened and they took action-big credit to them. I look forward to seeing a better version of this Mig 29 take to the skies hopefully in the near future

Perhaps a mod or upgraded part for those of us who already have the plane and haven't yet crashed it.