Cockpitbuilders.com

Main => General Discussion Board. => Topic started by: Bob Reed on February 10, 2018, 06:08:18 AM

Title: 737-800 flight model
Post by: Bob Reed on February 10, 2018, 06:08:18 AM
Well I am on the hunt for a good, 737-800 aircraft for P3D v4.. PMDG does not fit this goal! Is there anything else out there that I can use with Project Magenta? I am using their flight model but the thing is made of butter the way it flies through the air. No drag at all and because of that it is almost imposable to control the speed on a descent. I usually end up doing a circle on my way into approach to get me slowed down. So... What is out there? I have not found much....
Title: Re: 737-800 flight model
Post by: RayS on February 10, 2018, 09:21:13 PM
PM doesn't have any plans to update their flight model? Seems like a rather significant oversight if their incredible software has to be combined with a flight model that is apparently useless....
Title: Re: 737-800 flight model
Post by: jackpilot on February 11, 2018, 05:53:35 AM
Quote from: Bob Reed on February 10, 2018, 06:08:18 AM
I am using their flight model but the thing is made of butter the way it flies through the air. No drag at all and because of that it is almost imposable to control the speed on a descent.

It is, to some extent, how the 738 behaves. Speed control has to be managed carefully even in VNAV with decel points.
The best way when you control via the MCP is to reduce the VS from about 1800 to about 500 feet/min 2-3 miles ahead of the decel point and the aircraft will slow down. Spoilers at flight detent can help also .
I used briefly the PM flightmodel before switching to SimA and P3d4 and found it very well balanced.  (just my 2cents Bob)
Title: Re: 737-800 flight model
Post by: Trevor Hale on February 13, 2018, 02:19:20 AM
Apparently a 737 Pilot told Bob yesterday..  You can Slow down, or you can descend.... But you can't do both LOL...
Title: Re: 737-800 flight model
Post by: blueskydriver on February 13, 2018, 04:02:26 AM
I was thinking about this topic and it came to me that back years ago the biggest problem I saw was how the PM weights and balance would load into FSX (pre-Prepar3d). For some reason they would load wrong and really affect the characteristics throughout all phases of the flight, no matter what. If you think about it, a nose heavy plane is going to go down fast doing the descent; whereas tail heavy will cause oscillations since the trimming is trying to keep it level or in downward angle, but it just can't quite do it right.

Surely, some will say this is not the problem, but I tested many PM flight models during the beta phases back in those days, as well as even used TopCat, along with PFPX to manipulate the settings. And, what it always came back too was the weight and balance not setup right or transferring into the PM CDU correctly, then how FSX viewed it.

Therefore, I would always go into FSX weight and balance settings to make sure it matched what TopCat was telling the PM CDU to use...this always fixed the problem. Although, there are other things to look at, but I'd suggest for anyone having these problems to start with checking Prepar3d weight and balance settings. Also, if you're using TopCat or another program that injects these values, let me know if it comes over correctly and if it's correct when injected into PM CDU.

John
Title: Re: 737-800 flight model
Post by: crazydunc on February 13, 2018, 04:09:15 AM
Bob,

As we discussed last night (repeating it here for the wider audiences), A couple of our WorldFlight Team are 737NG Pilots for various airlines.

Their input was as Trev has quoted, "you can go down or slow down, but not both".

They all advocated the use of LVL CHG rather than VNAV when descending, to manage the Speed v ATC restrictions.

Regards,

Dunc
Title: Re: 737-800 flight model
Post by: FredK on February 13, 2018, 04:57:40 AM
I just want to report that the SimAvionics 737 model in conjunction with the most recent SimA update works extremely well operating in VNAV for me.

VNAV descents have become almost too easy now.  Just monitor speed and apply spoilers as required and you will comfortably get to your target altitude.  All works very smoothly regarding aircraft attitude and performance.   Previously I relied more on using V/S for descents when VNAV seemed to get a bit confused.

Fred K
Title: Re: 737-800 flight model
Post by: Bob Reed on February 13, 2018, 05:24:23 AM
I am currently testing the SimA flight model and I must say... What a difference! I can actually manage the speed in a decent. With the PM model I would slow the plane down to 220knts pull back the speed breaks to full and start down. Even in a 1700fpm decent, by 10000 I would be up around 290knts. Not this aircraft. Watch the banana and use the speed breaks and wow. Only thing I am experiencing on this aircraft is that it hand flies VERY differently. Not sure if I am just that used to the PM model or something is wrong. I do not remember Sam's sim flying like this. Left and right is the issue. I expect the plane to start returning to neutral as soon as I let pressure off the yoke but I do not expect it to snap back which this seems to do. This could be FSUIPC settings on my part. I will play with is some more....
Title: Re: 737-800 flight model
Post by: Trevor Hale on February 13, 2018, 07:54:41 AM
Quote from: Bob Reed on February 13, 2018, 05:24:23 AM
I do not remember Sam's sim flying like this. Left and right is the issue. I expect the plane to start returning to neutral as soon as I let pressure off the yoke but I do not expect it to snap back which this seems to do. This could be FSUIPC settings on my part. I will play with is some more....

Remember Sam is running ProSim Now and the ProSim model, so that may be the difference also.

Trev
Title: Re: 737-800 flight model
Post by: Bob Reed on February 13, 2018, 07:58:33 AM
Quote from: Trevor Hale on February 13, 2018, 07:54:41 AM
Quote from: Bob Reed on February 13, 2018, 05:24:23 AM
I do not remember Sam's sim flying like this. Left and right is the issue. I expect the plane to start returning to neutral as soon as I let pressure off the yoke but I do not expect it to snap back which this seems to do. This could be FSUIPC settings on my part. I will play with is some more....

Remember Sam is running ProSim Now and the ProSim model, so that may be the difference also.

Trev

I was talking more of the way it "feels" and yes the model is the difference. I want mine to "feel" more like his. It is adjustments I know that I will need to make.
Title: Re: 737-800 flight model
Post by: FredK on February 13, 2018, 09:42:59 AM
Bob -

Also remember that the SimAvionics model is specifically designed to work with the SimAvionics software suite which includes all the A/P tuning.  Otherwise there definitely will be anomalies.

Fred K
Title: Re: 737-800 flight model
Post by: blueskydriver on February 13, 2018, 09:46:34 AM
Hey Bob,

Look at this link and do the 30 day free trial:

https://prosim-ar.com/free-prosim737-trial/

John