Official Freewing MiG-29 Fulcrum Twin 80mm Thread

[GliderGuy]

My 0.5 mm carbon fiber sheets/planks arrived today. But, a 67F day and calm winds took me away from the planned work this afternoon.

I had plans to sheet the bottom and sides back there. But, once I got into the project tonight and studied the way the plastic rectangle is glued, I decided sheeting the bottom is sufficient to prevent any potential glue joint separation with flight time aging/fatigue.

Of course, doing the sides would add more stiffness, but just doing the bottom added quite a bit of additional stiffness. May need to add a thin washer between the FFS and support area if the sides of the support area are covered in CF to keep the clearance reasonable once the CF is added between the FFS and side of the support area.

You can see the incorrect color covering the area of the CF. Going by HD tomorrow and get the matching paint. Thought I could get close with what I had on hand....LOL = NOPE!

-GG

[RC30Flyer]

Nice work glider... mine is still sitting on work table as ive kinda lost motivation to finish. Going to get back to it soon tho. I reversed my elevator servos so that the horn is closer to the stab and get a slightly shorter pushrod for possibly more strength. Going to use 4-40 pushrod with dubro ball links on both ends.

[Scale Master]

Getting close to finishing the turbine conversion with K-45 and 3D printed CL tank. Initial calculations look good for weight and CG of about 13.5lbs TO weight and -15mm from factory. Here are a few happy snaps of the tank and turbine mounting so far.

Awesome! Where did u get the tank? I'd like to get one. This is my second attempt

[viper1gj]

Awesome! Where did u get the tank? I'd like to get one. This is my second attempt

Scale Master,

It was designed and printed by my friend Keith (Yellowbird911). He plans to upload it to Thingiverse and you can download and print as many as you want. He is not allowed to sell them because of free design software restrictions.

I plan on doing weight and balance today with the Xicoy CG machine and hope to report findings later tonight.
Gary

[Lcacing]

One thing that I’ve been wanting to fix is the angle of the elevator pushrod. Going trough my spare helicopter bin, I found a solution. I found a canopy spacer and added a swash plate ball link. This gives me just the correct space needed to move the pushrod near to 90 degrees. The ball link is bigger so will need to upgrade the pushrod to 4-40 and dubro links.
a lot easier that moving the servo outboard.

[janmb]

Getting close to finishing the turbine conversion with K-45 and 3D printed CL tank. Initial calculations look good for weight and CG of about 13.5lbs TO weight and -15mm from factory. Here are a few happy snaps of the tank and turbine mounting so far.

Great job, looking forward to the videos :D

[janmb]

One thing that I’ve been wanting to fix is the angle of the elevator pushrod. Going trough my spare helicopter bin, I found a solution. I found a canopy spacer and added a swash plate ball link. This gives me just the correct space needed to move the pushrod near to 90 degrees. The ball link is bigger so will need to upgrade the pushrod to 4-40 and dubro links.
a lot easier that moving the servo outboard.

Not to criticize, but I would be careful with going down that route. We've seen how fragile the alu horn is to torsion, and this will add a lot more arm in that regard.

I believe a much safer and stronger solution is to move the servo outboard.

[leithalweapon]

One thing that I’ve been wanting to fix is the angle of the elevator pushrod. Going trough my spare helicopter bin, I found a solution. I found a canopy spacer and added a swash plate ball link. This gives me just the correct space needed to move the pushrod near to 90 degrees. The ball link is bigger so will need to upgrade the pushrod to 4-40 and dubro links.
a lot easier that moving the servo outboard.

I think you will definetely twist the control horn. It may not permanetly bend, but will make the elevator feel mushy as the horn flexes. If you stiffen the horn you may be ok.

[RC Rich]

My 0.5 mm carbon fiber sheets/planks arrived today. But, a 67F day and calm winds took me away from the planned work this afternoon.

I had plans to sheet the bottom and sides back there. But, once I got into the project tonight and studied the way the plastic rectangle is glued, I decided sheeting the bottom is sufficient to prevent any potential glue joint separation with flight time aging/fatigue.

Of course, doing the sides would add more stiffness, but just doing the bottom added quite a bit of additional stiffness. May need to add a thin washer between the FFS and support area if the sides of the support area are covered in CF to keep the clearance reasonable once the CF is added between the FFS and side of the support area.

You can see the incorrect color covering the area of the CF. Going by HD tomorrow and get the matching paint. Thought I could get close with what I had on hand....LOL = NOPE!

-GG

Nice job! What's the thickness of the CF sheet and what kind of adhesive did you use?

[GliderGuy]

What's the thickness of the CF sheet and what kind of adhesive did you use?

Thanks - I ordered off Amazon. 0.5 mm. I sanded off all the paint, cleaned with isopropyl alcohol, applied J-B KWIK (JB Weld) 5-min epoxy to the CF, set it in place and held it for a few minutes.

Used a Dremel tool to cut the CF.

Here is the link to the CF. 1 sheet is all you need, but I ordered 2.

https://www.amazon.com/dp/B082PX95QL...ing=UTF8&psc=1

-GG

[DForbes]

OK, so I have read this complete thread. Is it just me or is there not a solution to the lawn darting issue yet or is this just a case of watch your speed with flaps and move along LOL?

[bandetx]

OK, so I have read this complete thread. Is it just me or is there not a solution to the lawn darting issue yet or is this just a case of watch your speed with flaps and move along LOL?

There is a solution that will work. Wait for v2

[GliderGuy]

OK, so I have read this complete thread. Is it just me or is there not a solution to the lawn darting issue yet or is this just a case of watch your speed with flaps and move along LOL?

Depends.....There is still a few that have had loss of elevator control for an unknown reason.

Mostly, it appears to be: Get the CG 10 to 15 mm aft of the mark AND don’t fly fast with flaps down.

Do any of the other upgrades you choose to do for added piece of mind.

Many are having a fun time with this MiG!!!! It is a sweet flying jet.

-GG

[xviper]

OK, so I have read this complete thread. Is it just me or is there not a solution to the lawn darting issue yet or is this just a case of watch your speed with flaps and move along LOL?

I don't not read any definitive solutions or reasons why some MiGs are doing the dirt dive. So far, I see only theories and visualizations as to what solutions may be for unknown problems. I'm going to start flying this thing with a bible in one pocket, a horseshoe in another and my lucky rabbit's foot hanging from my neck.

[janmb]

OK, so I have read this complete thread. Is it just me or is there not a solution to the lawn darting issue yet or is this just a case of watch your speed with flaps and move along LOL?

As long as you do, you will more likely than not be just fine.

The question is, at this point, what it takes for the model to earn (and deserve) confidence. There are a number of proposed (and demonstrated) reinforcements and upgrades that will certainly remedy any marginal design issues anyway

[GliderGuy]

I don't not read any definitive solutions or reasons why some MiGs are doing the dirt dive. So far, I see only theories and visualizations as to what solutions may be for unknown problems. I'm going to start flying this thing with a bible in one pocket, a horseshoe in another and my lucky rabbit's foot hanging from my neck.

Man....,If that doesn’t prevent a loss of control event, we’re all in trouble.

-GG

[mshagg]

Is it just me or is there not a solution to the lawn darting issue yet

Nope, and anyone who tells you otherwise is being disingenuous.

Plenty of good ideas but no definitive explanation for the crashes and thus, no sure fire way to avoid them. Xviper may be on to something in seeking solace in the occult.

[janmb]

Nope, and anyone who tells you otherwise is being disingenuous.

Plenty of good ideas but no definitive explanation for the crashes and thus, no sure fire way to avoid them. Xviper may be on to something in seeking solace in the occult.

While there are several factors in play for sure, I dare say Fred's video and the previous pics we've seen of the same effect, is pretty darn definite.

[GliderGuy]

While there are several factors in play for sure, I dare say Fred's video and the previous pics we've seen of the same effect, is pretty darn definite.

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.

Pretty convincing stuff and thank you for their sacrifices and contributions.

-GG

[xviper]

Man....,If that doesn’t prevent a loss of control event, we’re all in trouble.

-GG

I tried 4-leaf clover enemas for a while but I couldn't stand still for the whole flight. Didn't crash, though.