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Old Apr 16, 2011, 02:20 PM
Fly the Discombooberator!
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XB 70 Valkyrie Bomber by Nicesky

Originally bought from BRC Hobbies, full retracts (non Std) 4S Power, fantastic flyer, fast or slow, very stable, ROGrass and near vertical performance
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Old Apr 16, 2011, 06:23 PM
On the Edge of Space
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Exit 4, South Jersey, USA
Joined Dec 2007
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Very cool model. Have fun with that.
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Old Apr 18, 2011, 03:17 AM
Fly the Discombooberator!
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Quote:
Originally Posted by dLdV View Post
Very cool model. Have fun with that.
Thanks - is that a model SR 71?? I have a BP hobbies one still in the box I keep meaning to put together. Do you reckon it might need a gyro for roll stability??

Richard
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Old Apr 18, 2011, 09:01 AM
On the Edge of Space
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Exit 4, South Jersey, USA
Joined Dec 2007
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I fooled around with some on mine but only kept them a few flights. They did not seem to help much, but that may have been incompetence with gyros on my part. The part that helped most was to mix for more elevator travel than aileron travel.

I found the plane slow to respond to pitch control but quick to respond to roll control. I mixed to compensate for that.

My best advice for success would be to set it up for power to weight similar to the final stock version. It won't be a speed demon, but it will be a solid reliable model.
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Old Apr 18, 2011, 09:32 AM
Fly the Discombooberator!
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Joined Nov 2003
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Pitch response

Ah, OK. so lots of elevator but small aileron. Similar on the Valkyrie, need lots of elevator. Did you get down - pitching with increased throttle?? I have this on my GWS F15 , but compensated for that by mixing in some up elevator with throttle
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Old Apr 18, 2011, 09:54 AM
On the Edge of Space
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Exit 4, South Jersey, USA
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There were two issues in pitch. At normal flying speed it was fine in straight level flight.

During turns it would drop the nose, more so than a more conventional layout. Mixing so that it kept more reflex on the elevons through the turns solved that.

The other problem was at low speeds. The tail can stall and sink, and there will be more lift under the long, wide flat bottom nose than under the tail, resulting in an unrecoverable stall. The cure was simply to stay above that stall speed and avoid nose high attitudes.

I smashed mine to smithereens, so I may not be the best advisor. That said, I have one in the box to replace the old one. If you get going on your project, you could drop me a line and I'll start mine too. I like to compare notes on this plane.

The end came for mine while flying straight and level at altitude and cruising speed, it suddenly went sideways and fell from the sky. I couldn't determine the exact cause.
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Old Apr 18, 2011, 02:24 PM
Fly the Discombooberator!
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Hey that's a shame. Was it the BP hobbies one?? Must look up on here I think there is probably a build thread.

Maybe it may be better to modify it with the rear of the centre section as the (huge) elevator, with separate ailerons, dunno.

I think the Multiplex Sonic Liner will be next, already started to build, will start a build log. Will let you know when I start the '71
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Old Apr 23, 2011, 11:49 AM
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United States, FL, Sebring
Joined Feb 2006
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I've been flying the heck out of mine. The first weakness was the soft wire material used in the front strut. It folds so easily, I upgraded mine with better material and it has been holding well. Ditto on the dropping of the nose in tighter turns. Wide sweeping turns and/or reflex cures the problem.

XB-70 Ducted fan jet (3 min 3 sec)
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Old Apr 26, 2011, 12:31 PM
Fly the Discombooberator!
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Originally Posted by Joe 1320 View Post
I've been flying the heck out of mine. The first weakness was the soft wire material used in the front strut. It folds so easily, I upgraded mine with better material and it has been holding well. Ditto on the dropping of the nose in tighter turns. Wide sweeping turns and/or reflex cures the problem.

http://www.youtube.com/watch?v=di05t_BTQ_E
Same here - I changed my nosewheel retract for an E Flite electric one - I don't have the luxury of a hard strip, short grass instead so the U/C gets a bit more stress.

In fact, the only stock parts left on mine are the fan unit and main retracts
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Old Apr 04, 2013, 10:40 AM
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Joe

How much travel are you using on both Aileron and Elevator?
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