I want to confirm if in real life, multi engine aircraft (748 f.example) uses asimetric thrust to draw sharp curves at taxing.- In my case is the only way to do it, as the 748 ground handling is really tricking 

56 minutes ago, solito said:

In my case is the only way to do it

Do you use tiller axis or just rudders?

Just rudders, I cannot map the tiler action to some device

I use CH Yoke, Pedals and Quadrant

It depends on the airplane and the nose steering system.  For light GA twin engine airplanes, differential or asymmetric thrust can help tightly turn the aircraft. Ever for larger, transport category airplanes with hydraulic nose steering systems, differential thrust can aid in turning, but the turn has to be a very tight one.  Generally, pilots of transport category turboprops or turbojet airplanes do not use differential thrust when turning, but rely on the nose steering. I have no clue about the real HS 748.  There are some models of the King Air that pretty much require differential thrust to turn. 

Keep in mind that turboprop and turbojet airplanes that use differential thrust to aid in turning are pushing a lot of air behind them, and things do not react well to that on the ramp.  We have to very cautious with what is behind the airplane as we do a lot of expensive damage in a hurry if we're not careful.  That's another reason why we avoid differential thrust.  

In the business jets that I fly, I can't recall the last time I used differential thrust to aid in turning the airplane.

Rich Boll

3 hours ago, solito said:

I want to confirm if in real life, multi engine aircraft (748 f.example) uses asimetric thrust to draw sharp curves at taxing.- In my case is the only way to do it, as the 748 ground handling is really tricking 

@Solito,

Unfortunately, MSFS2020 aircraft have many flaws regarding handling and aerodynamics. IMHO the C152 and C172 (steam gauges) are close, we have some real-life drivers on these airplanes that can share their experiences.

Regarding the 748 (F x I) they got it wrong, to be specific on that matter yes, we use asymmetric thrust during turns exceeding 70 degrees. The amount of thrust is very low (just a tad above idle) and there is no concern of any damage in the vicinity.

Usually on the 744 748 up to gross weights of 330 Tons as soon as we release the parking brake (at idle) not adding any power the airplane will start slowly moving and accelerate to speeds up to 30 KTS or even higher in a straight line. 

The nose wheel is also controlled by the rudder for up to 7 degrees left/right while the nose wheel steering tiller turns the wheels up to 70 degrees left/right overriding the rudder steering.

The only hope is that "maybe" Asobo programmers to fix the correct coding or you can wait for other experienced developers to do the right job.

In GA asymmetric braking is common.

It is worth noting that the POH for the Cessna Caravan specifies the minimum turn radius on the ground as 33.65 feet pivoting on the inboard wheel with the inboard wheel locked -

 

Edited September 1, 20214 yr by Glenn Fitzpatrick

BOOMDA boomda boomda boomda BOOMDA boomda boomda boomda...

 

Diferential braking works OK for me at most aircraft, but the 748 doent seem to response to it

2 hours ago, solito said:

Diferential braking works OK for me at most aircraft, but the 748 doent seem to response to it

I don't think real 747 use either differential brakes or asymmetrical thrust for taxi. I believe they use tiller wheel. Until Asobo makes it as dedicated axis I think folks will struggle with airliner taxi

1 hour ago, sd_flyer said:

I don't think real 747 use either differential brakes or asymmetrical thrust for taxi. I believe they use tiller wheel. Until Asobo makes it as dedicated axis I think folks will struggle with airliner taxi

Please look at my previous post.

Yes we do.

Thank you.

33 minutes ago, killthespam said:

Please look at my previous post.

Yes we do.

Thank you.

Oh I missed that! Thanks! Is that normal for all 747 or particular company SOP? 

 Once I witnessed  myself as corporate jet used asymmetrical thrust while trying to turn around on the ramp and flipped two 152s that we parked 100 feet behind. From my experience with smaller twin when we use asymmetrical thrust to swing around, it usually calls for way more power on one engine vs if we used two.

31 minutes ago, sd_flyer said:

Is that normal for all 747 or particular company SOP? 

It's not a company SOP, they can't really have a procedure for everything.

As I said, usually a 747, 340, or 380 at weights up to 330 T as soon as we release the brakes the airplane moves on idle power on leveled taxiways (no slope), the asymmetrical power if used is just a tad over idle (maybe 5-10% more) and is enough providing that the other engines are running. Lots of power on these engines, actually at light weights below 300T we have to apply brakes when we taxi due to constant increase of the groundspeed.

Sometimes we taxi in 2 or 3 engines inbound or outbound.

Regarding braking during turns, it has to be a very tight turn, tiller is the king.

For the record, I was an AWACS driver and we did use differential braking and Asymmetric Thrust to aid on turns on the E3's - we even applied the same technique at times on C-130's.l  Just saying.  I never flew 74's but would find it hard to believe they don't use a similar technique.

Edited September 1, 20214 yr by DMullert