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Old Jul 17, 2013, 09:36 PM
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Joined Jun 2012
4 Posts
Random Nose Dives!?

Hey guys, I'm relatively new to RC and I've had quit a few experiences with planes crashing. However, I've never had a problem like this one. My friend and I build him a FT Flyer (Blue Dart). Looks great and construction seems to be very sound.(will post pics if needed.)
However we popped the electronics in the swappable fuselage and tried to maiden it. It would fly true for several seconds and then all of a sudden it would plunge into a violent nosedive. It is properly trimmed and flies level, but has a tendencies to dive randomly without user input. Checked everything and I can't detect the issue.
I figure it could 1 of 2 things.
1) Perhaps the radio is glitching from interference causing the servo to twitch? It is DSM2 only
2) The elevator servo is broken and moves unpredictably.

However I have not seen any of these issue in preflight and it has no other bad tendencies. I will further dissect this issue with field testing, but it looks like it may be a very hard mystery to uncover. Hopefully this is a basic beginner issue that you can set me straight on. Thanks in advance for your superior knowledge

Plane Specs.
1x Park300 1600kv motor
1x 18A Plush Speed Controller
2x HXT900 9g servos
1x Turnigy 500mAh 3s Lipo
1x Orange 6ch Rx w/o failsafe
1x T-SIX 6ch Orange Transmitter(DSM2)
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Old Jul 18, 2013, 11:56 AM
3D? I only got two thumbs!
United States, MA
Joined Jul 2012
1,627 Posts
Perhaps those are actually stalls?
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Old Jul 18, 2013, 01:44 PM
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Joined Jun 2012
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From flying my Flyer, I know how extremely docile this plane tends to be even at stall speed. Unless there is something very aerodynamically wrong with the air frame(which seems impossible, the thing looks great), the stall would not be nearly this violent. Also this occurs well above stall speed. Thanks though. Keeps the ideas coming!
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Old Jul 21, 2013, 07:05 AM
An itch?. Scratch build.
eflightray's Avatar
South Wales U.K.
Joined Mar 2003
14,400 Posts
Have you tried a radio range check ? (Try a genuine walk away with the servos working, not pressing the 'range check button', assume the Tx has one).

Rx antenna away from any metal, wires, carbon, and straight not bent ?

Tx antenna angled over to one side, (shouldn't point straight at the model).

If a servo has a problem, replace it. They are cheap enough, and it's not really worth risking ruining the plane, motor, prop etc.
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Old Jul 25, 2013, 09:07 PM
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Parkflyer81's Avatar
Australia, TAS, Brighton
Joined Dec 2005
1,443 Posts
Ive had the same issue with DSM2 products. I've changed out to another type of radio module and RX units, never had a problem since.
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Old Aug 04, 2013, 09:05 AM
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Wilson, NC
Joined Aug 2009
229 Posts
Hi ttrando
You state that the elevator servo is broken and moves unpredictably. The elevator controls the pitch and you have unpredictable pitch motion. Seems you have answered the problem. Replace the elevator servo.
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Old Aug 06, 2013, 05:21 AM
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Joined Aug 2013
20 Posts
I had the same problem

I had the same problem and it was my radio. I upgraded to a better radio and things are fine now.
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