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Aug 10, 2008, 03:46 AM
My plans are in my blog
Rusty-Gunn's Avatar
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Adam and I went out to fly the SR-71s tonight, with fading daylight happening. My SR-71 must be jinxed, another problem. This time a servo quit, at launch time no less. I landed it with no damage though.
Adam was next, and flew quite well for someone who has practically no experience with elevon planes, and hasn't flown much at all the past year. We did some circuits with his, even checking its speed range. It hit the tundra with no damage, just cartwheeling. He let me fly it next, and I proceeded to drill holes in the sky! Rolls and loops. Slow and fast. Very enjoyable to fly this plane. I also hit the tundra a few times doing low go-arounds so my wife can video the plane, but the spongy tundra just lets the plane bounce, with no damage, but a tail did pop off, so I flew it with one tail. The nose of his plane did become creased though.
We've decided to retire these planes, with him building a Rebel KF, and I'll do an improved SR-71 (I didn't like how the batt stuck out the rear of the cockpit). Adam's little brother and his cousin got the planes now, as chuck gliders.
Here are some pics. We'll work on the new vid soon.

Heres the link to the Youtube video.
SR-71 Baby Blackbird prop jet, vid 2 (0 min 52 sec)
Last edited by Rusty-Gunn; Aug 10, 2008 at 07:31 AM.
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Aug 10, 2008, 03:59 AM
Look outside the Square
Boxhead's Avatar
Hey Rusty, if its not Tundra its snow banks, but they just keep bouncing back . Great to see the young fella's getting the retired one's. Got to start them early . I'm looking forward to V2. This is one great looking model.

B x
Aug 10, 2008, 04:27 AM
My plans are in my blog
Rusty-Gunn's Avatar
Thread OP
Thanks Kev, I enjoy this one a lot. I'm getting better at flying elevon planes, This "yank and bank" system was a bit unusual to me, but i'm getting the hang of it. I love doing rolls at high speed, having not done this simple maneauver before. I'm currently helping Adam with his Rebel, so he can play "catch-up" with his flight training. I'll begin the next SR-71 tomorrow.
Aug 13, 2008, 01:19 AM
My plans are in my blog
Rusty-Gunn's Avatar
Thread OP
Finally had time to do an improved SR-71 Baby Blackbird. This has a larger and longer fuselage/cockpit and has the prop slot further backwards.
I have not installed the electronics, but expect to do so tomorrow.
I took build pics, for a future build log and plans.
Aug 13, 2008, 09:40 AM
TJC
TJC
Crossweave king
TJC's Avatar
Rusty, that is just exellent! Looking forward to the plans.
Aug 13, 2008, 09:16 PM
My plans are in my blog
Rusty-Gunn's Avatar
Thread OP
I finished the plane. Although all the equipment can fit inside the cockpit, I didn't have enough room to move the battery rearward to fine-tune the balance statically. Its about 1/4" nose-heavy. I can solve this with a lighter battery, but will need to make a JST-to-Dean's adapter.
I'll fly the plane as soon as the weather allows. Plans coming soon.
Aug 18, 2008, 02:45 AM
My plans are in my blog
Rusty-Gunn's Avatar
Thread OP
I needed to retest the Version 2 SR-71 Baby Blackbird (original #2 was jinxed), and we went out tonight. She flies very well indeed. Here are some pics. Vids and plans to come tomorrow. Yippee!
With us we flew with Ryan, who flew his Cub, and yet a new flyer, Abe, who flew a EDF F-22 made by SAPAC. We don't have pics of the F-22, and hope to do so another time.
Aug 18, 2008, 06:32 AM
Registered User
Congratulations Rusty. Glad it has all worked out, it looks so good it just had to fly well.
My next build

Rudolf
Aug 18, 2008, 06:58 PM
Insert comment here:
totalywicked's Avatar
Well that’s the problem with planes all of them go up and all of them come down but the difference is some of them come down better then others…

So Rusty when are you going to share plans with us????
Aug 18, 2008, 08:46 PM
My plans are in my blog
Rusty-Gunn's Avatar
Thread OP
Plans are posted. Any questions, please ask, and I'll get right back to you. YThanks for the interest. This plane, in both short-nose, and long-nose, flies very well. I'm sure you'll all enjoy flying the SR-71 Baby Blackbird. I expect to head out later to fly mine again.

Edit :CG is 12.75 inches from the nose of the long-nosed version, and 10.5 from the short-nosed version, measured down the center.
Last edited by Rusty-Gunn; Aug 21, 2008 at 08:30 PM.
Aug 18, 2008, 09:11 PM
My plans are in my blog
Rusty-Gunn's Avatar
Thread OP
Here are some build pics. A few notes...
I don't know what the actual angle the tails are slanted at, so I merely guessed on mine, TLAR method.
You most likely will need to trim a few spots here and there, depending on the foam you use.
You may skip the KFm step if you choose, and use a spar of your choice to stiffen the wing set, as this should lighten up the AUW some.
You can change the actual size of the elevons if you want to. Mine were two inches full-length per side on the short-nose, but were tapered two inches at the inner (center) area, and about 1.5 inches at the ends.
You can also change the position of the prop slot, but I'd recommend near the rear, so as to keep all electronics under the cockpit.
Cut the prop slot to fit your prop length.
Aug 19, 2008, 02:30 AM
Registered User
Rusty, which 2805 motor are you using the 2840kv or 1600kv has always been a problem having the same part no. You do say you are using 3's batteries so at a guess the lower kv motor. I have made this mistake before running 3's on the higher kv motor and it eats batteries real quick and from memory the thrust was half my problem.

Rudolf
Aug 19, 2008, 10:24 AM
My plans are in my blog
Rusty-Gunn's Avatar
Thread OP
Rudolf... lower KV motor IIRC. I spin an APC 8x3.8 slow fly prop, using a 1000 mah 11.1v 3 cell pack, 20 C.
To me, speeds are very fast, vertical climb is excellent, and slow flight is also very good. I enjoy this plane a lot. The weather is a bit high, so once it calms down a bit I'll give more flights, and report back with more info.
Good luck on the build.
Aug 20, 2008, 12:10 AM
My plans are in my blog
Rusty-Gunn's Avatar
Thread OP
Rudes, as it turns out, the 2805 motor doesn't want to spin well (after dunking it in water last week), so I had changed it to a B2208/14 1450 kv motor. I apologize for the misinformation I posted above.
Aug 20, 2008, 12:13 AM
My plans are in my blog
Rusty-Gunn's Avatar
Thread OP
Here is the vid #3 from Youtube of the SR-71 I flew yesterday.
SR-71 Baby Blackbird vid 3.
SR-71 Baby Blackbird vid 3 (0 min 35 sec)


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