OHM NASA_747_SCA

[OrbitHangar]

Author: hutchison66

Hi There, here's the Boeing 902 SCA whith a higher quality model and Accurate undercarriage, I've spent along time getting model and the undercarriage working in Orbiter, and trying to get photo realistic textures for the 747.

The shuttle model is the Orginal model by Kev Shanow but it was just static so I've started to animate  the gear extends and have started to do the aero surfaces (not working at the moment  Done something stupid fix on the next update)

I've made up an Enterprise for the ALT missions based on Kev's model and using the textures from David 413

Thanks to Kev for the Shuttle Model and to David 413 for the textures for the Shuttle's( Kev's model used these)

Keys

Left Shift Numbpad   3   start Engines

K      Extend/ Retract Flaps

G      Retract/Extend Undercarriage

J     Jettison payload   tail shroud first  then Shuttle  (will Have to sort that, with an update  so both separate together)

Shuttle---   G  for undercarriage extend

have a nice flight

We're Jusst a Dot

Happy Christmas

David

 



DOWNLOAD

 

[Marg]

This model is quite good, only cockpit missing. But I noticed something (also on C-5) - shadowed areas of the plane are very dark. Isn't it something in material settings?

EDIT: It is - ambient settings were 0.2 0.2 0.2, was easy to correct.

 

[hutchison66]

Hi there thanks for that I'm not good at textures I took the texture from the best photo I could find but will look at sorting it ASAP.
The cockpit is a texture BOE-Cockpit I've no idea why its not showing up as it works fine on my machine but will try it on one of my other machines.
I was trying to make a better SCA for us, but it is a work in progress I always fiddle with my projects will continue to improve it
thanks for the info on the materials but it is some thing I'm still trying to get my head round.thanks
david

 

[DaveS]

If you need high-res photos of the SCAs (which has the tail numbers of N905NA and N911NA respectively), go here and download 747 SCA.7z. Note that as the file is in the 7z format, 7-Zip is required to open the file.

---------- Post added at 03:14 PM ---------- Previous post was at 01:58 PM ----------

I'm getting a CTD when I try to take-off. As soon as I apply any thrust at all, Orbiter CTDs. This is true for all SCA versions.

 

[hutchison66]

CTD on Thrust

oh that's strange Have you tried any of the other keys like K or G I've checked it on a bare Orbiter and the addon worked fine, Have you installed spacecraft 3 first maybe if you post the log might get an idea what is going on and I can fix it

 

[DaveS]

oh that's strange Have you tried any of the other keys like K or G I've checked it on a bare Orbiter and the addon worked fine, Have you installed spacecraft 3 first maybe if you post the log might get an idea what is going on and I can fix it

Seems like something got seriously screwed up with my original Orbiter installation for whatever reason. A fresh installation and now everything is working fine.

 

[Spook27]

Thanks for sharing your efforts David. This is great work; the working undercarriage is much appreciated, good animation, and it will be feasible to fly Ferry and ALT missions with this great combo.

However, with respect, despite the improved textures and 3D, why not go for D3D9 Client compatibility? Going back to the heavy black umbras and solid shadows of pre D3D9 Client really looks and feels like a step backwards. D3D9 Client at last managed to get Orbiter looking really good. Without D3D9 Client, the sim is pretty much obselete graphically and no 3D or texture improvements will help this.

Therefore; please consider making your addons compatible for latest best looking version of the sim.

 

[AssemblyLanguage]

I have this excellent addon mostly working on Orbiter 2016 and I modified it to work with Spacecraft4.

To stop it from falling under the ground on Orbiter 2016, I moved the rear landing points back 20 meters. I don't know if that is a correct value but it is the first value I tried and it worked.

I increased the main thrust to 4.44e5 which I think is correct for a B747. Now it will reach takeoff speed before the terrain at the end of the Shuttle Landing Facility runway bounces it into flight.

As noted elsewhere, the Spacecraft j key payload jettison doesn't work on Orbiter 2016

This is my first go at Spacecraft addons. I tried adding flap lift values but it didn't appear to have any effect. I haven't played with the wheel brake values yet.

 

[DaveS]

I increased the main thrust to 4.44e5 which I think is correct for a B747. Now it will reach takeoff speed before the terrain at the end of the Shuttle Landing Facility runway bounces it into flight..

The correct total sea-level thrust for the JT9D-7J gas turbine engines should be 863136 [N].

The basic empty weight is different for each of the two SCAs. NASA 905, the first SCA has a empy weight of 144396.062 kg while NASA 911 has empty weight of 146657.436 kg. The Maximum Take-Off Weight (MTOW) for both is 323702 kg. Maximum Landing Weight is 272400 kg.

Maximum fuel load is 143603.378 kg.

 

[PhantomCruiser]

I must admit I haven't fiddled around with this addon much, but have anyone tried "ReleaseMe MFD"? I'm not sure which Addon I'd gotten it from (pretty sure it was on of the Greg Burch spaceplanes though). It might be worth a shot since the [J] key isn't working. :shrug:

 

[gattispilot]

Why not just attach versus payload.

 

[Donamy]

Jettison works for me.

 

[AssemblyLanguage]

Jettison works for me.

On Orbiter 2016?

 

[Donamy]

Yes . I use it with my cubesat launcher.

 

[AssemblyLanguage]

FLAP_LIFT with Spacecraft4

I haven't been able to make FLAP_LIFT have any effect with Spacecraft4.

Does it work?

I've watch the Flight Data Recorder while trying values from 5 to 50,000 with no effect. What is a good value for the B747 SCA?

Help appreciated.
Thanks

 

[Donamy]

Not sure if that works or not. Vinka would be the one to ask.

 

[AssemblyLanguage]

The correct total sea-level thrust for the JT9D-7J gas turbine engines should be 863136 [N].

The basic empty weight is different for each of the two SCAs. NASA 905, the first SCA has a empy weight of 144396.062 kg while NASA 911 has empty weight of 146657.436 kg. The Maximum Take-Off Weight (MTOW) for both is 323702 kg. Maximum Landing Weight is 272400 kg.

Maximum fuel load is 143603.378 kg.

Thanks to DaveS I updated the [AERODYNAMICS] .ini file. Now it will not takeoff.

I am an Electrical Engineer that needs a crash course in Aerodynamic Engineering. The wing cord, length and area look reasonable for a 747 so I'm guessing I need to add a lift profile and an efficiency value. Any help would be appreciated.

[AERODYNAMICS]
; lift/drag attack point of the vertical airfoil
VAIRFOIL_ATTACK=(0,0,-0.5)
; wing chord length of the vertical airfoil
VAIRFOIL_CHORD=20
; wing area of the vertical airfoil
VAIRFOIL_AREA=270
; wing aspect ratio of the vertical airfoil
VAIRFOIL_ASPECT=2.266

 

[AssemblyLanguage]

With research on 747 specs, I have aerodynamics settings that will get the 747 SCA off the ground and handle reasonably realistically. However, takeoff speed is over 160m/s. The acceleration rate is OK and it reaches takeoff speed at about the correct point on the runway. I've moved to the dry lake at EDW with a runway long enough for testing.

I think I am missing lift from the flaps. The flap animation works but according to the flight data recorder, the flaps do not have any effect on the lift.

Here are a subset of the .ini file:

[AERODYNAMICS]
VAIRFOIL_ATTACK=(0,0,0) ; lift/drag attack point of the vertical airfoil
VAIRFOIL_CHORD=14.63  ; wing chord length of the vertical airfoil
VAIRFOIL_AREA=511  ; wing area of the vertical airfoil
VAIRFOIL_ASPECT=6.95   ;span squared / wing area  59.6^2/511
VAIRFOIL_EFFICIENCY=17.7   ; CL/CD
VAIRFOIL_CD0=0.031
VAIRFOIL_LIFT_1=(-10,-0.6,0)  ;vertical airfoil lift profile for 747 DU1
VAIRFOIL_LIFT_2=(-7.5,-0.4,0)
VAIRFOIL_LIFT_3=(-5,-0.2,0)
VAIRFOIL_LIFT_4=(-2.5,0.10,0)
VAIRFOIL_LIFT_5=(0,0.3,0)
VAIRFOIL_LIFT_6=(2.5,0.6,0)
VAIRFOIL_LIFT_7=(5,0.70,0)
VAIRFOIL_LIFT_8=(7.5,1.05,0)
VAIRFOIL_LIFT_9=(10.0,1.25,0)
VAIRFOIL_LIFT_10=(12.5,1.5,0)
VAIRFOIL_LIFT_12=(15.0,1.75,0)

FLAPS_ATTACK=(0,0,0)
FLAPS_AREA=112.54
FLAPS_LIFT=15.0
FLAPS_ANIM=5

Comments appreciated.

 

[AssemblyLanguage]

By moving the rear landing points forward, I was able to pitch up at takeoff rotation speed and takeoff before the end of the runway.

Now, I'm attempting to get the correct rotation moment. If I use values from this Wikipedia page https://en.wikipedia.org/wiki/Pitching_moment, the forces are too strong to achieve rotation. Does anyone know where I can find the correct moment coefficients for a 747?

Thanks.

[AERODYNAMICS]
.
.
VAIRFOIL_LIFT_1=(-10,-0.6,0.15)  ; 0.15
VAIRFOIL_LIFT_2=(-7.5,-0.4,0.1) ; 0.1
VAIRFOIL_LIFT_3=(-5,-0.2,0.05) ; 0.05
VAIRFOIL_LIFT_4=(-2.5,0.10,0.0) ; 0.0
VAIRFOIL_LIFT_5=(0,0.3,-0.1) ; -0.1
VAIRFOIL_LIFT_6=(2.5,0.6,-0.15) ; -0.15
VAIRFOIL_LIFT_7=(5,0.70,-0.2) ; -0.2
VAIRFOIL_LIFT_8=(7.5,1.05,-0.27) ; -0.27
VAIRFOIL_LIFT_9=(10.0,1.25,-0.34) ; -0.34
VAIRFOIL_LIFT_10=(12.5,1.5,-0.5) ; -0.5
VAIRFOIL_LIFT_12=(15.0,1.75,-0.65) ; -0.65

 

[Marg]

So - now I am into this... I noticed that .ini files for SCA contained mass 15000kg, and i wondered why B-747 flies like a charm, almost Cessna.
But there was a problem - when I detached shuttle from mate-demate device on the top of SCA-747, plane "fell" through the ground. Changing the mass to ~ 144000 kg (values proposed by DaveS), solved the problem.
But flying is problematic...