LevelUp 737-700 porpoising at cruise

[Jetmechanicdave]

I had some porpoising issues on my flight in the LU -700 at cruise with LNAV and VNAV engaged.  Cycling the AP fixed the issue temporarily, but then issue returned several times within my 2 hour flight. The -800 did not have this problem FYI, and I did a 2 hour leg in it.  Couple other sim pilots experienced porpoising in the -700 in a Facebook post as well.

Edited January 2, 2022 by Jetmechanicdave

[Dhood320]

I had this issue in the -800 earlier. Hopefully it gets fixed!

[Junafani]

I have had this on -600 on climb and descent. I think most of these have happened when I alt-tabbed out and came back but I think it once happened without alt-tabbing. F-sim was 19.900/sec after coming back for few seconds so that might be connected?

[samy_k97]

Hi,

Well I learned a new word today.

We've been getting feedback regarding Thrust and Flight Modelling not acting correctly. We are actively looking towards this and will see if we can improve this a lot.

[Torkermax]

Great. I may need some hemorrhoid treatment to keep flying.

[JumboAg]

same in the 600 late in cruise.  Not overspeeding at all. Normal flight until it randomly started.  Immediately started bleeding off speed when it happened.  Was near enough to TOD that I just started down a bit early to stop it.  

[WiredWomble]

I had the -600 oscillate above and below the G/S on approach.  Did it twice on the same approach (I performed go around first time), no issue with winds as was 7kt headwind.

I have heard it also happen on an RNav and if you watch FD2S stream before he disconnects the AP you can see it suddenly go to -1000fpm then back to 0.

[FlyingVulpes_]

Same here!

[samy_k97]

Hi,

Can you guys please confirm that you had "Experimental Flight Model" enabled on the X-Plane settings? It seems as the option on the Plane Maker isn't working reliably.

[chasekelly21]

@samy_k97 Can you confirm we need to have "Experimental Flight Model" enabled when flying the aircraft? I had this issue as well but EFM was not enabled.

[samy_k97]

22 minutes ago, chasekelly21 said:

@samy_k97 Can you confirm we need to have "Experimental Flight Model" enabled when flying the aircraft? I had this issue as well but EFM was not enabled.

Current finding of the Team suggest that it's best to activate "Experimental Flight Model" in order for the aircraft to behave better.

If possible could you give me your Log from when you were experiencing problems with the aircraft?

[jiffyJet]

Hi there, 

Any update on this, please? Having the same porpoising  issue as others are or have experienced. 

[jamalabama]

I have found in the 800 when I change the view to outside certain angles produce the porpoising I use sim speed at max. The only way I can get back to normal is go back inside the cockpit hit vnav and it settles. Its a pity as I like to look up from under the plane to help my poor old pc with frames haha

[deltabravo1123]

Is there still no solution to this issue? It happens every single time the sim speed increase above 1.5X. Really starting to lose patience and confidence with this aircraft. 

Edited October 14, 2022 by deltabravo1123

[jamalabama]

7 hours ago, deltabravo1123 said:

Is there still no solution to this issue? It happens every single time the sim speed increase above 1.5X. Really starting to lose patience and confidence with this aircraft. 

Its such a pity cause i use flightaware to choose my flights and 737-NG comes up a lot and I love this plane it is done so well but I have to keep hitting the vnav button every 30 seconds or so drives me nuts hoopefully theres a solution somewhere.

[deltabravo1123]

I think I might have found something.. Make sure the "Experimental Flight Model" is chosen and then reload the aircraft. I hadn't done that previously. Also, do not increase the sim speed over 2X. For me at least, I can do 2X and it is okay, but anything above that it will do the bouncing.

[jamalabama]

I haven't reloaded before as I am usually at or approaching cruise I will try that. I found sometimes I can use 2x but then sometimes I can't random!