New Release SR-71-R Vers: 0.1.2 - May 2, 2015

[Blake]

Version: 0.1.2
Orbit Hanger: [ame="http://www.orbithangar.com/searchid.php?ID=6777"]SR71r 0.1.2[/ame]

- Fixed altitude hold bug.
- Tweaked atmospheric handling.
- Added 're-entry procedure' to the documentation.


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After several years of tinkering, I've decided now is good time to share this with the community.

What this is:
- A fictional modification of the SR-71 Blackbird to outfit it for orbital operations.
- A test-bed and playground for me to learn the various technologies needed to create Orbiter add-ons.
- Hopefully something fun to play with in Orbiter.

Driving concept:
The driving mission for this project was to create a vessel based on the SR-71 that would have the ability to fly to the ISS, dock, and then return and land. Obviously the Blackbird was never designed for such a mission so some modification had to be made along the way. I have tried to be true to the spirit of the Blackbird and stay as realistic as possible to its capabilities. However, I am not a pilot or avionics expert, so I may have missed widely on some points. Suggestions are welcome.

This add on is entirely self-contained with no external dependencies outside of the stock Orbiter distribution (2010 version). Code, meshes, textures are all created from scratch and when stable I do intend to release it all.

Some details:
- The Pratt and Whitney engines had to go. The 'R' in SR-71-R is for rocket.
- The RSO cockpit and the number 1 fuel tank have been removed to make way for a cargo bay that contains the docking ring. The fuel from #1 has been moved to the now empty forward end of the nacelles.
- The nacelles themselves normally point down 3 degrees. Since the rockets must push through the COG, the nacelles are now aligned with the body. I hope SR-71 purists will forgive this alteration
- Fuel is fictional 'Delta Glider' fuel. 80,000 lbs allows the vessel to ascend and descend from orbit on one take of gas.
- The Blackbird was designed to take heat, but not re-entry heat, and I don't assume magical heat resistant paint. There is plenty of fuel for a powered descent. There is a trick for going from powered descent to atmospheric flight without over-stressing the aircraft, and I hope someone here knows what that is.

Features:
- Functional virtual cockpit.
- Atmospheric flight intruments.
- Atmospheric auto pilots (heading, altitude hold, speed hold).
- Animated control surfaces, doors etc.
- Simulated power system with fuel cell, APU, hydraulics etc.

I consider this basically complete, but with some rough spots. I honestly could spend another five years tweaking the various parts of this vessel but feel it is to a point to share and get feed back.

As I stated previously, I'm not an expert in these systems so any suggestions to improve reality or 'fun' factor are welcome.

Enjoy.

 

[WolfAngriff]

Hi Blake,

First thank you for this wonderful bird. I've made two flights, one athmospheric, one orbital. And will make other ones this afternoon. First feed-back :

The suborbital flight was a real pleasure. The "plane" is precise, very stable, and realy immersive. The touchdown was soft and on the runway. The plane is pretty slow in its manoeuvre, but i guess the real black bird doesn't move like a F16 ! Auto pilot works like a charm, only pleasure !

The orbital flight was good too on the ascent, no problem. I've made an Ecc=0.00003 using Burn Time MFD, 256km alt. without any problem. The reentry was more... artistic ;-)

The AP kept the AoA without any problem, but when i was at 130/140 km high, the plane began to move right-left and left-right with a strong banking. I used Base Sync MFD and AeroBrake MFD (only for the datas), 55° pitch AP, aiming Cape Canaveral, i've made my touchdown in Australia ! I'm not saying that there is any problem with the plane. First feeling is to say : more powerful RCS ! But an experienced orbinaut says : be careful with the joystick, keep calm, look at what you're doing, read the doc and give it another try. So I'll make other tests with other parameters, with a higher reentry angle for example, and give you the results here.

Even if this bird is not finished, it is already very fun to play with, very immersive, but i think needs some skills to be domesticated. Well... It's a Black Bird and Orbiter is not an arcade game ! I'll be back soon with other results.

 

[Blake]

Hi Wolf (can I call you Wolf?)

Thanks for the feedback. Yes, the maneuverability has been on the back of my mind. I suspect the real Blackbird is somewhere between the current setting and an F16 . I'm reviewing the specs, I believe my surface control areas are too small.

I've also found a bug in the altitude AP causing it to porpoise.

I'm glad you are enjoying it, I had a lot of fun creating it.

 

[Star Voyager]

I have a few Habu books in my collection and most pilots say the SR-71 handles a lot like an Airbus A300.

 

[mojoey]

I have a few Habu books in my collection and most pilots say the SR-71 handles a lot like an Airbus A300.

A300s probably don't disintegrate around the pilot at cruise, though.

 

[WolfAngriff]

Hello Blake,

As i said, the way the plane flies in suborbital mode is not a problem IMO. Just remember to not engage it in dogfight, except against an A300s.

But i can't manage to bring it back home. As i touch the upper athmosphere, around 80 km alt, it seems like pitch, bank and yaw become impossible to be kept. So i will try with a loooong aerobrake, nearly one orbit. I hope to be back soon with good news.

...and yes, you can call me Wolf

 

[Blake]

I appreciate the feedback.

I have put up a new version that has the correct control surface areas. I'm adjusting the lift settings for each to try and get something that feels realistic and is comfortable to fly.

The re-entry procedure is what I came up with through trial and error, and is not always very graceful. That should at least be a starting point. Any suggestions for refinement are welcome. Turns out the SR-71 manual I have is missing the atmospheric re-entry section