Official Freewing MiG-29 Fulcrum Twin 80mm Thread

[fredmdbud]

Where's the video?

[Turbinefancy]

Agree GG.
TV would cure that though.



Not necessarily. Flaps down typically have a pitch-down contribution, particularly at high AoA.

My MiG is coming back together. She's almost ready to fly again minus a few cosmetic touch-ups...

I find it very interesting that after adding reflex to my flaps, I had to re-trim stabilator (less up) for level flight. But dropping flaps does not induce pitch change for both half & full flaps. I don’t overspeed my flaps though, only dropping them after speed stabilizes at 50% throttle or lower. I suppose the flap induced downwash increase the negative angle of attack on stabilator to offset the down pitching moment from the flaps. Or is there another explanation?

[Airguardian]

I suppose the flap induced downwash increase the negative angle of attack on stabilator to offset the down pitching moment from the flaps. Or is there another explanation?

No, that is correct :)

Depends on CG and particular airframe and speed though, so the effect is not consistent through every aircraft and condition.
Su-35 behaves very similar and even the F-18...

BUT, different stuff applies at different AOA.

Can't compare effect of flaps on stab effective AoA with plane flying level or 40º plus alpha.
Of course with such high angles of attack, the wing is stalled and CP can vary wildly depending on airframe planform and design.

With MiG locked in high alpha, I'm pretty sure the flaps would have a net pitch-down contribution.
You can even see fullscale Su-35 and Su-30SM using the flaperons as tailerons to control pitch attitude when flying at extreme high alpha.

[Shaun Evans]

Hi

My MiG pitches UP with flap deployment, so there's quite a bit of stabilator trim for level flight with flaps. Who knows..

Do these ARF's come with the camo decals already applied? My new one should be there when I get home.... ;)

[viper1gj]

Hi,

So yesterday I found that not-so-sweet spot with the nose-high stall/falling leaf deal. I was experimenting with MCAS, with full flaps down, and before you knew it, the plane was not responding to anything I did. Not throttle, not control surfaces... nada. Before I realized I was stuck, I'd lost enough altitude (by trying to get out of it by throttling back) that sustained idle wasn't really an option. For the second time in the plane's life, tall weeds saved the day. She went in, somewhere in the Tijuana River estuary--full of bones, sewage, snakes, ticks, all manner of detritus and bacteria--and emerged with only two bent missiles. Turbine was still running! Other than the ordnance, there was zero damage. Someone must've been praying for me....

Now to figure out how to get out of that regime should it ever happen again...

Hi Shaun,
I'm running somewhere between 6-8 degrees down thrust in my X-45 conversion. Mine will normally fly out of the deep stall pitch hang up with full down elevator.
Gary

[Shaun Evans]

Has anybody used the Top Design struts, wheels, and brakes that are supposed to be a drop in replacement on the Mig-29?

Did anyone ever respond to this? I have some on order.....

[Shaun Evans]

Nobody?

[Airguardian]

Guess that's a no.

[viper1gj]

Did anyone ever respond to this? I have some on order.....

I gave up on getting feedback on the struts and ordered some JP 75mm wheels and brakes so I could fly my Mig from pavement.

[Shaun Evans]

Hi

Haha, I did the same, but they wouldn't mate up to my stock struts, so I used some Intairco pneumatic ones. I went ahead and order3d some of these for my new one.

[GliderGuy]

Hi

Haha, I did the same, but they wouldn't mate up to my stock struts, so I used some Intairco pneumatic ones. I went ahead and order3d some of these for my new one.

Brakes sound good. I just flew off a 400 ft piece of pavement with calm winds. It needs to be wide enough to make the far end turn wide enough so you won’t tip over if you are a bit hot. But, otherwise the pavement is sufficient. Most landings used about 300 ft.

With any wind at all…400 ft is more than enough without brakes. Distance derived from Google Earth.

Conditions:
75F
calm
29.86 inHg
elevation 600 ft MSL
No “S” turning to manage energy on roll out


-GG

[viper1gj]

Hi

Haha, I did the same, but they wouldn't mate up to my stock struts, so I used some Intairco pneumatic ones. I went ahead and order3d some of these for my new one.

Putting mine on tomorrow. WIll let you know how It goes!

[Shaun Evans]

Hi

Well I'm flying turbine, so I need brakes to be legal. With a bit of headwind, I can get her off in 200' and stopped in 250'.

[Airguardian]

My MiG pitches UP with flap deployment, so there's quite a bit of stabilator trim for level flight with flaps. Who knows..

Perfectly possible.
Re-read the part of my comment about these dynamics being angle-of-attack/CG/speed dependent. ;)
Again, at high angles of attack, the net contribution should still be pitch down.

I bet you weren't flying at 45º AoA when you noticed flaps induced pitch-up on your jet.

In this (your) case, this would happen because the flaps change the angle of attack of the stabs (more negative -> more pitch up). So despite the flap contribution alone being pitch down, the airflow wake deflection affecting the stabs (pitch-up) can have a net balance towards pitch up.

[fredmdbud]

Angle of attack on the stabs from the post-flaps air could very well stall them, rendering them ineffective, not more.

[Shaun Evans]

Angle of attack on the stabs from the post-flaps air could very well stall them, rendering them ineffective, not more.

I'm pretty sure my entire airframe was stalled.

[Airguardian]

At about 45º and higher AoA, I'm pretty sure the stabs on the MiG are getting most of their airflow from UNDER the wings anyway...

They will be stalled all the same (45º is a lot) but that's not to say there is not an aerodynamic resultant force from their interaction with the air (Of course there is).

[viper1gj]

Putting mine on tomorrow. WIll let you know how It goes!

Well they didn't. No way with out machining or JB weld. Not going to do either. I returned them and ordered the Top Design struts. I replaced my K-45 with an X-45 and its flying great from grass but no way to stop on pavement. I'll just have to wait for the mail now.

[Shaun Evans]

Well they didn't. No way with out machining or JB weld. Not going to do either. I returned them and ordered the Top Design struts. I replaced my K-45 with an X-45 and its flying great from grass but no way to stop on pavement. I'll just have to wait for the mail now.

Yep

The flanges on the hub were way too shallow. I had to either machine (or cut) some G-10 or metal to make a shaped shim and bolt it onto the strut or glue it on. So now I have a set of 75mm wheels/brakes for something else I guess...

[Shaun Evans]

My struts showed up. Gotta say, the springs are so heavy, you can barely compress the struts at all. I've got 1/4 scale birds that don't have springs this stiff....