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Anyone else have the alphasim SR-71?

Pro Member Trainee
toddbreda Trainee

I recently purchased the FSX-ready SR-71 from AlphaSim and the level of detail and flight dynamics is incredible. In fact, almost too good. It comes with an extensive flight manual that they recommend mentally consuming before flying. The wording is taken from the actual SR-71 flight manual so needless to say half this stuff is going right over my little flight sim head.

I'm finding it extremely difficult to fly a full flight. If you're not totally aware of the proper gauge watching, CG, fuel tanks, weight, et al, the engines shut down or you lose control completely.

Is there anyone else that owns the FSX-ready SR-71 from alpha sim, and if so, any step-by-step instructions on how to fly it in layman's terms?

It's a totally bad ass plane and I would love to fly it without emergency landings.

Pro Member Captain
Luke (warlord40) Captain

Yeah I've got it too, along with about 20 alphasim planes however, havent had time enough to look through the manual as yet, I'll get back to you.

Pro Member Trainee
toddbreda Trainee

Okay, I just had my first successful supersonic flight with it tonight...From O'Hare to Seattle...Took it to 85,000 @ 3.5 Mach...Fun!!

The key (for me at least) is to take it up to the max ceiling very gradually with minimal AOA throughout the climb. Full afterburners and I used AP pretty much the entire flight until I got within 50 miles or so of my final approach. I don't use AP much when flying (I like the symbiotic nature of flying) but for the SR-71 it's almost mandatory.

(Make sure your pitot and de-ice switches are on!)

Once I was at max speed and ceiling, I switched to tower view just to get a sense and appreciation of how fast this sucker would be going by if you were watching from the ground.

Making constant adjustments to the AP was critical for a smooth flight. I switched the CG control panel to Auto so it pretty much takes care of the fuel management issues sense my flight was under 2 hours. If you're going for transonic flight, you will need to study the manual to learn how to manually adjust the fuel tanks for CG purposes (Make sure Forward Fuselage is set to on for climb...I actually kept it on for the whole flight).

The Fuel Management and CG aspect of the SR-71 is still Greek to me.

One of the things I was running into trouble on my earlier attempts were because of compressor stalls. In the flight procedure manual it states: The aircraft will experience compressor stalls at angles of attack above 10 degrees at altitudes above 25,000 feet if the indicated airspeed is below 300 KIAS.

When you are used to flying very forgiving planes (by comparison), that spells a lot of compressor stalls in the novice stages.

Landing is different too because the delta wing creates a high level of "float" on landing, so you need to make sure you are pressing the stick forward instead of the flare we all are used to with normal planes. I couldn't figure out why it didn't want to land at first!

When I first flew the alphasim SR-71, I was disapointed that it was so hard to fly. I was spoiled with the freeware versions which is ridiculously easy to fly. Now, I love it. I figure if I can master the SR-71, most anything else I fly will feel like a piece of cake.

I have nearly 2,000 landings in FSX but none feel as satisfying to me as the 6 or so from the alphasim SR-71A.

Pro Member First Officer
zakk hutton (chez64) First Officer

i love how the 2 engines just dominate the "wing"

Pro Member Trainee
toddbreda Trainee

Well, I spoke too soon. Ever since my successful supersonic flight, I haven't been able to repeat it. Around 55,000-60,000, even with the AP running, the compressor stalls occur. I switch on the restart button and eventually I can get them started again before I have to emergency land, but somehow I end up losing all control and all I can do is watch it crash.

FRUSTRATING!!

(I need to read the whole manual from start to finish).

Pro Member First Officer
zakk hutton (chez64) First Officer

toddbreda wrote:

Well, I spoke too soon. Ever since my successful supersonic flight, I haven't been able to repeat it. Around 55,000-60,000, even with the AP running, the compressor stalls occur. I switch on the restart button and eventually I can get them started again before I have to emergency land, but somehow I end up losing all control and all I can do is watch it crash.

FRUSTRATING!!

(I need to read the whole manual from start to finish).

a mug of cocoa and some bed time reading then eh?

Pro Member Trainee
toddbreda Trainee

Okay, I've finally deciphered the problem. It's actually quite simple, really.

You can basically never allow the SR-71 to dip below 300 KEAS once you are over 25,000 feet. What's confusing with the SR-71 at first is the KEAS/KIAS values versus Mach speed. It's quite confusing because even if your Mach speed is increasing, your KEAS can still be decreasing, so you can't let it dip below 300.

So as long as I watch the KEAS and make sure I do what I need to do to keep it above 300, it never compressor stalls. Once you've played around with the gauges/AP/fuel management, there's a method to the madness and then it becomes an absolute ball to fly.

Now that I'm getting comfortable with it I'm going to go for my first transonic flight complete with refueling midair!

I hope my crash course is helpful for those who get the alphasim SR-71.

Pro Member First Officer
zakk hutton (chez64) First Officer

i fly rescue planes if you need them!!

Pro Member Trainee
lcorthell Trainee

Im having some major troubles to. ill be crusing at 80,000 ft at about mach 3.2, and sometimes randomly the sr will go out of control and yaw violently. not too sure whats its caused by, the only the i can think of is a compressor stall, or imbalanced fuel. The fuel to me seems unlikly because i do follow the fuel chart. anybody know?

Pro Member Trainee
toddbreda Trainee

Hmm. Normally, once I'm at 85,000/3.2 Mach she's steady freddy. Do you have your CG set to auto (forward fuse set to on), and AP engaged? With these settings I've never had a problem.

Getting it to 85K/3.2 is the hard part. This is the only plane I have to use AP for most of the flight in order to avoid compressor stalls in unstarts.

Pro Member First Officer
rob (Habu) First Officer

What's confusing with the SR-71 at first is the KEAS/KIAS values versus Mach speed. It's quite confusing because even if your Mach speed is increasing, your KEAS can still be decreasing, so you can't let it dip below 300.

It's not that confusing if you think about it. You are accendind and as you do, the air density is getting less and less. This affects KEAS, which is really amount of airspeed over the wings, which is also amount of air to engines. On ascent, you ascend by KEAS, so try ascending at 320 KEAS.If you can set auto pilot to do this, it will control the rate of climb and probably throttles. Real SR Pilots used 320, I believe and fuel management could be manual or auto. Try opening fuel crossfeed valve if it's like the real SR.
I have no experience with this SR for Flight Sim but I worked on the real SR-71 for 17 years. Back to Airspeed. Did you know that the SR-71 never flew faster than aprox 450 KEAS? At sea level 450 KEAS would be aprox 450 knots groundspeed. But at 80000 ft, 400 KEAS is over 2000 MPH gound speed (due to less air density at 8000 ft. With the SR, the limiting factor to speed was always the engine inlet air temp which is limited to 427 degrees C

Pro Member Trainee
toddbreda Trainee

Thanks for the information Habu! What an honor it must have been to be part of such an exclusive, elite unit. I sure wish this plane was still active today.

Pro Member First Officer
rob (Habu) First Officer

Me Too ! And it was a honor to work with The Best maintenance people, The Best pilots and The Best Aircraft ever built !!

Pro Member Trainee
cookedinlh Trainee

Does anyone here experience warninglights going GREY during climb. Some of the edges of the gauges do to but if there is an emergency a warning light will go RED but not all of them do just some.'

Have I got an install problem maybe or missing some textures?

Pro Member Chief Captain
RadarMan Chief Captain

cookedinlh wrote:

Does anyone here experience warninglights going GREY during climb. Some of the edges of the gauges do to but if there is an emergency a warning light will go RED but not all of them do just some.'

Have I got an install problem maybe or missing some textures?

It could be that you have most of the slides up too high and the video card can't keep up with the graphic intensive lights.

The add-on shockwavelights has been known to cause problems if you have that.

Radar

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