Anyone else have the alphasim SR-71?

toddbreda · Trainee Joined: Feb 01, 2008 Posts: 59

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.

warlord40 · Posted: Sat May 31, 2008 2:23 am Post subject:

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.
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toddbreda · Trainee Joined: Feb 01, 2008 Posts: 59

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.

chez64 · Posted: Sat May 31, 2008 9:06 am Post subject:

i love how the 2 engines just dominate the "wing"
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toddbreda · Trainee Joined: Feb 01, 2008 Posts: 59

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).

chez64 · Posted: Mon Jun 02, 2008 11:02 am Post subject:

toddbreda · Trainee Joined: Feb 01, 2008 Posts: 59

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.

chez64 · Posted: Tue Jun 03, 2008 3:59 pm Post subject:

i fly rescue planes if you need them!!
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