Official Freewing B-2 Spirit Bomber 86" Twin 70mm EDF Jet

[xviper]

(If I ever get mine. It's currently "lost in Yonkers [Singapore]".

It wasn't "lost". They gave me the wrong tracking number. I've been tracking NOTHING. It's supposed to go onto our mailman's truck this morning and be delivered this afternoon.

[kallend]

„REFLEX“
It‘s about the „camber line“ (a curve halfway between upper and lower surfaces) of an airfoil. For tailless aircraft, an airfoil with a „reflexed camber line“ will help to improve stability.
When looking at the FW B-2 wing, there seems to be such an airfoil at the inner portions, but it soon changes to a conventional „semi-symmetrical“ airfoil (look at the outer wing root). To keep „the reflex“ over most parts of the wing, the control surfaces need to be trimmed up.


https://en.wikipedia.org/wiki/Camber_(aerodynamics)

Indeed.

An airfoil where the camber line curves back up near the trailing edge is called a reflexed camber airfoil. .

[Radar-Guy]

„REFLEX“
It‘s about the „camber line“ (a curve halfway between upper and lower surfaces) of an airfoil. For tailless aircraft, an airfoil with a „reflexed camber line“ will help to improve stability.
When looking at the FW B-2 wing, there seems to be such an airfoil at the inner portions, but it soon changes to a conventional „semi-symmetrical“ airfoil (look at the outer wing root). To keep „the reflex“ over most parts of the wing, the control surfaces need to be trimmed up.

https://en.wikipedia.org/wiki/Camber_(aerodynamics)

[Amahoser]

Hey all.
I'm learning an editing software so I recut the previous B-2 video with the on board camera. Let me know if this is a better format for future videos please.

old cut

https://youtu.be/rmQOo2E0fRs

new recut

https://youtu.be/LFn-5J1sh3I

Thanks
Jose

[xviper]

Here’s a company that builds a position control box for the RV-10 type aircraft. They use the term REFLEX for negative (up) control surface position.

https://www.aircraftextras.com/FPS-PlusReflex.htm

Good ‘nuff for me as are the other posts which define reflex as up control position. I won’t hesitate to use the term going forward to indicate “up”.

Therefore, for the B-2…

Setting the inner surfaces to 8 mm reflex and the outer (non-clamshell) surfaces to 4 mm reflex as a starting point for a maiden is a perfectly acceptable use of the term REFLEX…IMHO.

-GG

This is interesting. It’s the first time I’ve heard of this. I guess you just showed an old dog a new “trick”.

[GliderGuy]

Here’s a company that builds a position control box for the RV-10 type aircraft. They use the term REFLEX for negative (up) control surface position.

https://www.aircraftextras.com/FPS-PlusReflex.htm

Good ‘nuff for me as are the other posts which define reflex as up control position. I won’t hesitate to use the term going forward to indicate “up”.

Therefore, for the B-2…

Setting the inner surfaces to 8 mm reflex and the outer (non-clamshell) surfaces to 4 mm reflex as a starting point for a maiden is a perfectly acceptable use of the term REFLEX…IMHO.

-GG

[xviper]

Full-scale sailplane pilots use the less ambiguous terms “positive” and “negative” when discussing flap and aileron settings for take-off and landing configurations.

Flap down or aileron down with flap down = positive configuration

Flap up or aileron up with flap up = negative configuration

Sailplane aircraft owner’s manual often just say flaps down or flaps up.

Very often negative flap and negative aileron is called for in the POH the first part of then take-off roll to enhance aileron control. Going back to this configuration for the last part of the landing roll.

-GG

So true for a plane like a sailplane, which can have flaps and ailerons. However, this plane, being a flying wing, doesn't really have flaps and ailerons. They only used those terms to differentiate the inner and outer control surfaces. Regardless of them being "innies" or "outies", they are still elevons and they should have called them inner and outer elevons. That being the case, I've always considered "reflex" as being UP elevator and nothing really to do with flaps/ailerons. All my other flying wings have always referred to using some "reflex" to aid in launch. This was also suggested for the A-10 models.

[xviper]

I guess my thought with the steering gyro is to be able to adjust gains independently.

But I would definitely say I'm not familiar enough with the gyro yet.

The thing with the E-52 RUD gyro is that those who have connected the master gain have indicated that there is little difference between 100% and 0% on the "air" rudder. So, adjusting that gain on the gyro isn't really all that important for flying. What I'm sensing from those who have played with it, have suggested that perhaps the AIL gain could be lowered by a few % and the ELE gain could be raised by a few %. What happens with the RUD gain appears to be of little consequence to the "flying" rudders, only to the steering ground rudder. To be able to adjust the gains independently, one would need the programmer.

[GliderGuy]

I always thought that "reflex" was UP elevator.

Full-scale sailplane pilots use the less ambiguous terms “positive” and “negative” when discussing symmetrical flap and symmetrical aileron settings for take-off and landing configurations.

Flap down or aileron down with flap down = positive configuration

Flap up or aileron up with flap up = negative configuration

Sailplane aircraft owner’s manual often just say flaps down or flaps up.

Very often symmetrical negative flap and symmetrical negative aileron is called for in the POH the first part of then take-off roll to enhance aileron control. Going back to this configuration for the last part of the landing roll.

AND….many POH’s avoid the confusion all together. The POH simply lists 1, 2, 3, 4, 5, 6, flap position markers. 3 may be 0 or neutral flaps with 2 and 1 = symmetrical flap up/aileron up positions and 4, 5, 6 = symmetrical flaps down/aileron down.
-GG

[SanExup]

I guess my thought with the steering gyro is to be able to adjust gains independently.

But I would definitely say I'm not familiar enough with the gyro yet.

[xviper]

My understanding is they are the same? May need to research it. Wash out is twisting the wing to reduce AOA at the tips and reflex is adding up ailerons to do the same.

I always thought that "reflex" was UP elevator.

[Evan D]

My understanding is they are the same? May need to research it. Wash out is twisting the wing to reduce AOA at the tips and reflex is adding up ailerons to do the same.

[mongo]

Thanks for the enlightenment of the "reflex". It's just ingrained in my head and it's easier to say.
Agreed on the second point, but I have a couple laying around, I'll see how I feel about it after the maiden. (If I ever get mine. It's currently "lost in Yonkers [Singapore]".

isn't twisting the wing so as to have less AOA at the tip than the root called Washout?

[Gravythe clown]

I think you might be mixed up about the gyro gain. High gain causes control surface induced oscillation as speed increases. Wind buffeting that causes your bouncing around should get worse as you lower gain, but that's another discussion.

I had the LX YF-23. Flew it twice and barely got it back in one piece. I gave up on it and gave it away to someone who kept it as a static model.

Yeah I got that, it was oscillating more than I liked last weekend even at low speed. So today I thought I would lower the gain off the git (bad day to play around with it because of wind). I really wont Know where my happy point is until I get a clean air day.

I will say the first flight on the YF-23 had me excited to fly it more. This let me know she is tamable.

Gravy

[xviper]

Good reports...

Reflex... We are using the term incorrectly. Reflex is twisting the wing to have a smaller angle of attack compared to the root. When we add up elevon we are just adding pitch up, we are not adding reflex.

I really like the Assan steering gyro. I have them in more than a few planes. That said the gyro in the B-2 does a good job of keeping it straight. I think that it has so much gain programmed in that it does a good job. It does so well I don't see any reason to bypass steering on this plane.

Thanks for the enlightenment of the "reflex". It's just ingrained in my head and it's easier to say.
Agreed on the second point, but I have a couple laying around, I'll see how I feel about it after the maiden. (If I ever get mine. It's currently "lost in Yonkers [Singapore]".

[Evan D]

I agree 100%.

I think you might be mixed up about the gyro gain. High gain causes control surface induced oscillation as speed increases. Wind buffeting that causes your bouncing around should get worse as you lower gain, but that's another discussion.

I had the LX YF-23. Flew it twice and barely got it back in one piece. I gave up on it and gave it away to someone who kept it as a static model.

[xviper]

Got 2 more today. Wind was choppy and switching between S and E. Take off going S into wind, 7 minutes later landing with E cross wind. While flying the thing bounced all over the place because of the choppy wind. I did lower my gain down to 60%, but she was still bouncing. The wind chop was even noticed on my mirage which usually cuts through with no issues.
One perfect landing one that had two small skips.
I was showing a buddy the difference in preloading the bank with rudder verses not. He could see the difference easily. She’s not a trickster or a hot rod, but man does she look good in the sky.
I do have my steering on a separate channel, but may try it back again off the gyro.
I haven’t had much issues until second flight today. And yep I over corrected and did a drifting take-off. If I had intended to do it, it would have been the coolest thing ever, however instead it left a little brown in boxers.

Also did a re-re-maiden on the YF-23. She’s still in one piece, but that’s another story.

Gravy

I think you might be mixed up about the gyro gain. High gain causes control surface induced oscillation as speed increases. Wind buffeting that causes your bouncing around should get worse as you lower gain, but that's another discussion.

I had the LX YF-23. Flew it twice and barely got it back in one piece. I gave up on it and gave it away to someone who kept it as a static model.

[Evan D]

Good reports...

Reflex... We are using the term incorrectly. Reflex is twisting the wing to have a smaller angle of attack compared to the root. When we add up elevon we are just adding pitch up, we are not adding reflex.

I really like the Assan steering gyro. I have them in more than a few planes. That said the gyro in the B-2 does a good job of keeping it straight. I think that it has so much gain programmed in that it does a good job. It does so well I don't see any reason to bypass steering on this plane.

[xviper]

The big difference is that the Assan is a heading hold gyro and the stock one is a rate gyro. Assan will track the centerline of the runway much better.

That explains why the Assan works better as a ground steering gyro. I should not have said "works" the same. However, the way the front wheel responds to the plane being yawed on the ground "looks" the same, except that the Assan returns to center much slower because of what you stated.

[radfordc]

No reason except that you're just substituting one by another. The one in the stock gyro works exactly like the Assan. My friend did his ground test this morning with his B-2 and the response is exactly the same.

The big difference is that the Assan is a heading hold gyro and the stock one is a rate gyro. Assan will track the centerline of the runway much better.