Originally Posted by SlydWyz

I did see in another thread that someone made a 3D printed SR-71, specifically for use with the Ultrix electronics. I’ve been contemplating getting a 3D printer ever since.

If it's the one I'm thinking of, then not printed: https://www.rcgroups.com/forums/show...s#post43682137


He's done several Ultrix-based birds:

It was in the UMX Addiction thread....

This is the post, if I linked it right... https://www.rcgroups.com/forums/show...&postcount=199

If I had a 3D printer, I'd be all over this already. The B2 is pretty sweet, but if there was 1 super cool plane that I remember seeing pictures of and hearing rumors about when I was a kid, the SR-71 stands out

Originally Posted by SlydWyz

If I had a 3D printer, I'd be all over this already. The B2 is pretty sweet, but if there was 1 super cool plane that I remember seeing pictures of and hearing rumors about when I was a kid, the SR-71 stands out

As someone who owns a few, I'd caution against letting lack of a printer mislead you into thinking of the printer as more key (or easy to get good results with) than it is. The whole foaming filament thing sounds quite tricky to get dialed in.

I suspect you can do better with foam board and hand tools.

I am 100% certain you can do better with balsa.

At least in terms of ending up with something that looks like an SR-71 and flies well.

Well I have one of the SR-71 mentioned above. For me it printed quite easily and flies great. I believe I posted in that thread. I loop it, roll it, fly it inverted and a lot of the time simply cruise around. The Ultrix receiver and power is just magic. The bottom line is it flies great and just bounces when you crash. I have yet to even damage the original. I was going to print a spare.....but so far no need.

As for the printer- I agree with UncleChris- just buying a printer isn't the goal, you need to spend time with it to get it printing properly. It takes time, so you have to have an interest in learning it. The LW-PLA foaming filament is pretty easy to dial in once you have the printer working properly with regular PLA.

I’ve been thinking about one for a while, as I think it’ll be great to print my own parts for some of my ground vehicles as well. This was the first time I’ve seen it used for airplanes where I’ve really thought to myself that I need to stop thinking about one, and finally commit to buy.

All the talk of diminishing UMX choices and a recent encounter with a hungry tree branch has me ordering a third Ultrix. Took in a large amount of old welding cable to the scrap yard and they gave me $536. I took it a a sign! I also bought a 14 ounce throw bag and 200 feet of throw line for my next tree assault.

I duct taped some PVC pipe together with a dowel between each link to get my planes down, easy to disassemble, but only good for 50 or so feet.

Originally Posted by queadlunnrau

I duct taped some PVC pipe together with a dowel between each link to get my planes down, easy to disassemble, but only good for 50 or so feet.

Mine was 51 feet apparently!

I use a very long tent pole from a portable marquee to get mine down. It's one of those poles that's made up of lots of small tubes connected together by an internal elastic rope.

Originally Posted by Torburner

Mine was 51 feet apparently!

Fly lower?

Originally Posted by AirDOGGe

Fly lower?

Crash less!
That sucker was in a great spin and headed down fast. Snapped it back level and it beelined for the tree. Problem with snapping back into safe mode is the slow turn response it imposes. The fact that I am getting older has absolutely nothing to do with my glacial response rates. The high rate mode is so intense! I have a hard time getting enough altitude without running out of space. One of the problems with the 18000 kv motors is the speed it can move at.

Your turn rate will be much better in safe mode if you use the rudder. Of course with the ultrix rudder is differential thrust so you have to also have the throttle up.

That's how I make sharp turns with my X420 VTOL. It has the shallowest bank angles I have ever flown assist with. A little diff throttle and it practically makes a U-turn.

Originally Posted by jayb79

Your turn rate will be much better in safe mode if you use the rudder. Of course with the ultrix rudder is differential thrust so you have to also have the throttle up.

I really like how well the yaw steering works, especially with the 18000kv motors. My problem was getting my fingers back on the sticks after flipping the mode switch! The plane flipped out of the spin so damn close to the Ultrix eating tree that the reaction time for evasive action occurred at the same millisecond my brain also had to process the sound of the plane swacking into the foliage. I need more room than my narrow field to really push the envelope of what this plane can do.

I'm having a hard time typing over the deafening noise of the crickets, but here goes....
I was working on a friend's Ultrix, putting in a new board, and 13500kv BB motors in it, when I discovered one of the servos wasn't working((he had a real bad crash).
So I put in a spare servo I had. The servo came with, what I thought, an extention. When I plugged it in the board it made a couple of beeps. When I tried it it didn't work. So I took the "extension " off and it worked.
Off to the field to try it and the elevators and ailerons were reversed on the radio.
Long story short, I think my "extension " was some kind of reverser. So I plugged it back into the servo, waited for the beeps, took it off, and all is right with the world. The bad servo is still bad.
I'm a little disappointed in the performance of the 13500kv ball bearing motors. The stock motors are better performing. Maybe if I try the stock props on it ( after drilling of course).
After putting in a new board and stock motors in my plane, it is flying very well. Oiling the shafts of the new motors really helps. 20 flights on the new set up so far, 270 flights on the plane.
Best plane in the world.