Official Freewing MiG-29 Fulcrum Twin 80mm Thread

[Yellowbird911]

Agreed! Just curious

[HK111]

If I could find servos that are much higher torque and still have them fit in the same hole, I'd consider it.

MKS HV69, direct fit, much stronger than the Freewing upgrade servo. I have them built-in and they seem good.

[radfordc]

After adding 120 g of lead to the tail the CG is about 10-15mm aft of the wing marks with two 6000 packs (850 g each). Yes, she's a big pig for sure but the flights are good. With no wind the takeoff from grass was uneventful. It flys smooth and stable with good speed and enough vertical to pull big loops. Flight timer set to 4:00 and batteries are fine upon landing. After two dozen flights I've decided that it probably isn't going to dive into the dirt at any moment. I use half flaps for takeoff and immediately retract them. I don't drop the flaps for landing until the gear is down and speed is slowed significantly.

[Evan D]

The big MiG has really good energy retention. On 6000's I'm getting 6 minutes, take off roll to full stop on the runway.

[GliderGuy]

For the exhaust nozzle touch ups, I got a close match by mixing the following in the approx ratios. You will need to eyeball it:

TIMIYA TS-29 / 90% / semi gloss black
TIMIYA TS-30 / 15% / silver leaf
TIMIYA AS-14 / 5% / olive green (USAF)

If anyone has an exact match, please post.

-GG

[xviper]

MKS HV69, direct fit, much stronger than the Freewing upgrade servo. I have them built-in and they seem good.

Thank you.

[xviper]

It may be in here somewhere but can't find it. Has anyone had an uncontrolled dive that have upgraded to higher torque servos. Not the Freewing higher torque but something with 2 to 3 times the torque. The fellow on Youtube that put a K55 in his has got to be doing over 125mph but has larger servos.

Going by the poll conducted by Evan D on the "other" forum, nobody in that category has responded, so the answer is "no" but that doesn't mean it hasn't happened. I'm of the opinion that anyone who would go to lengths to upgrade those servos to something that much stronger, is on top of these forum discussions and very likely knows about that poll. The only crashes where the user were likely not on these forums are the first several in SE Asia where they flew those things a month before the rest of the world got theirs and they flew them with wild abandon and likely not reading the manual first. Which, BTW, I have not seen anymore reports from that part of the world since those early days of this plane, of crashes happening. Did those flurry of crashes put the nix on the MiG and nobody there has since purchased it?
My top curiosity for the K55 guy and the guy with the 8s system would be ................. what would have happened if the flaps were deployed during those high speed runs, even 1/2 take off flaps? (Not that I would advocate either of them to try it just to satisfy our morbid curiosity.)

[radfordc]

The big MiG has really good energy retention. On 6000's I'm getting 6 minutes, take off roll to full stop on the runway.

I'm not far off that. I fly until the timer goes off at 4 min. By the time I get the gear and flaps down, fly the approach, land and taxi in I'm over 5 min. Last flight my batt was still above 25% so I've got a little cushion if needed.

[radfordc]

My top curiosity for the K55 guy and the guy with the 8s system would be ................. what would have happened if the flaps were deployed during those high speed runs, even 1/2 take off flaps? (Not that I would advocate either of them to try it just to satisfy our morbid curiosity.)

As long as we're wondering....I wonder what would happen if the full size Mig dropped flaps at Mach 1?

[GliderGuy]

I'm not far off that. I fly until the timer goes off at 4 min. By the time I get the gear and flaps down, fly the approach, land and taxi in I'm over 5 min. Last flight my batt was still above 25% so I've got a little cushion if needed.

Always best to keep a safety margin in case something requires a go-around. And, longer flight times equate to longer charge times which I must consider to keep the batteries/charging stations rotating to minimize time on the ground.

A 4 min flight keeps my charge time to a little less than an hour (6000). This is perfect for my battery/charger set-ups. Last flight of the set = first batteries almost ready to go. I put in a few P-38 flights after the last MiG flight for good measure and a little time pad between MiG sets.

4 min allows for hot doggin’ too. But everyone’s flight styles are different. Best to keep an eye on the after-flight cell voltage and decide for yourself.

-GG

[HaroldAnderson]

As long as we're wondering....I wonder what would happen if the full size Mig dropped flaps at Mach 1?

Don't stop there. How about a high speed diving pass for the spectators!!

[RudyD54]

For the exhaust nozzle touch ups, I got a close match by mixing the following in the approx ratios. You will need to eyeball it:

TIMIYA TS-29 / 90% / semi gloss black
TIMIYA TS-30 / 15% / silver leaf
TIMIYA AS-14 / 5% / olive green (USAF)

If anyone has an exact match, please post.

-GG

I’ve touched up my nozzles (they came missing some spots of paint out of the box) with Tamiya Gunmetal X-10 which was recommended by Alpha and I’ve found it to be an exact match.

[Airguardian]

Fred’s video and Borat’s photo = I’m done making upgrades after the CF sheeting on the bottom back there to harden the structure (against possible glue joint separation) for an extended number of flights.

You missed half the point of that video, which is that not only stab housings bend, but also the stabs themselves... even much more so than the stab assembly, judging from my own tests. Glassing the stabs or strategically adding flat CF spars to their top and bottom surfaces would be in order.

For sure, the root cause appears to be extreme force in certain situations. I guess it's the mode of failure which is the question. Servo overloaded? Mechanical binding? Surface effectiveness when it takes on the shape of a bannana? Regardless, efforts to support this area of the fuse should head most of them off.

The video made it pretty clear IMO that the stabs were deforming regardless of what happened to the servos.

[GliderGuy]

Hi Airguardian - The stab deformation was max in the flaps down/high speed/dive part of the video....not going there! Also - I am concerned about inducing flutter if messing with the stab mass balance.

How are you avoiding the potential for flutter if changing up the FFS? Re-mass balancing? Should this be a concern? YouTube shows various RC birds eating dirt when they flutter!

Looking at the base of the vertical stabs and tips of the rudder photo published later by Fred....not seeing much housing / structure deformation. Mainly FFS deformation. That’s why I added CF only to the bottom to stave off rectangular box / foam glue joint separation.

-GG

[viper1gj]

My buddy Keith (Yellowbird911) and I working on K-45 turbine conversion have upgraded out stab mounts using this method and it stops the flexing and twisting of the stab mounts. Used 6mm aluminum rods 190mm long to anchor the stab pivot rod into the nozzle using E6000 glue. I found the RustO spray dark bronz metalic to be a close match for the nozzle color. The Tamiya X-10 Gunmetal matches the silver covers forward of the nozzles.

[Jet jocky]

Reinforced the elevator mounting area on my mig. Used 1/32 ply on the inner and out sides and also the bottom. Sanded and used 30 min epoxy. Also upgraded the servos to promodeler 150 oz. torque servos, yes servos are a little pricey but better for my piece of mind.

[GliderGuy]

Looks good Jet Jocky. Watch the FFS root to support clearance with the 1/32 ply being there. You may consider adding a flat washer spacer.

As the FFS bends down under high loads (especially flaps down high speed) that gap may close and jam any servo motion.

-GG

[Jet jocky]

Thanks for the like gliderguy , repainted with the paint from Home Depot can't tell there was a mod done. Won't get a chance to fly till spring though. Will do my othere mig next.

[HK111]

Reinforced the elevator mounting area on my mig. Used 1/32 ply on the inner and out sides and also the bottom. Sanded and used 30 min epoxy.

Thanks for sharing the pictures. How happy are you with the result? Do you get a significant reduction in bending / torsion? I'd sure hope so.

[mshagg]

Here's some clips from flying this morning, rigged up a camera mount that fits on a weapons pylon to get a view of what's going on back there.