Rv-10 pilot reported losing directional control during the takeoff roll; consequently; the aircraft ...

Narrative:

While conducting my third flight of the afternoon. After an initial ground roll; tracking the centerline the aircraft began deviating to the left. I began to correct initially with right rudder but this had little effect. As the deviation progressed; we neared vr (rotation speed) and I felt the aircraft becoming airborne. Simultaneously; I attempted to apply coordinated right aileron and rudder inputs but the controls felt 'blocked' to the right. I immediately reduced power to idle; the aircraft settled and tracked into the grass between taxiway and [the] runway. There were no reported injuries. During the roll out the aircraft struck several lights and the taxiway sign (as determined by airport operations post incident). Flight control freedom of movement was normal during the control check in the run-up area; immediately post incident (I moved the control services by hand); and during the taxi back to the hangar. There was also no indication of a locked left brake during the taxi to the run-up area; the initial takeoff roll; or during the taxi back to the hangar.the co-pilot seat passenger's right hand was observed firmed grasping the co-pilot's stick immediately after the aircraft had come to a stop in the infield. However; I have nothing indicating as to when he placed his hand there or whether his feet were also on the rudder pedals.

Original NASA ASRS Text

Title: RV-10 pilot reported losing directional control during the takeoff roll; consequently; the aircraft departed the paved runway surface and struck a taxiway sign and several lights.

Narrative: While conducting my third flight of the afternoon. After an initial ground roll; tracking the centerline the aircraft began deviating to the left. I began to correct initially with right rudder but this had little effect. As the deviation progressed; we neared Vr (Rotation Speed) and I felt the aircraft becoming airborne. Simultaneously; I attempted to apply coordinated right aileron and rudder inputs but the controls felt 'blocked' to the right. I immediately reduced power to idle; the aircraft settled and tracked into the grass between taxiway and [the] runway. There were no reported injuries. During the roll out the aircraft struck several lights and the Taxiway sign (as determined by Airport Operations post incident). Flight control freedom of movement was normal during the control check in the run-up area; immediately post incident (I moved the control services by hand); and during the taxi back to the hangar. There was also no indication of a locked left brake during the taxi to the run-up area; the initial takeoff roll; or during the taxi back to the hangar.The Co-pilot seat passenger's right hand was observed firmed grasping the Co-pilot's stick immediately after the aircraft had come to a stop in the infield. However; I have nothing indicating as to when he placed his hand there or whether his feet were also on the rudder pedals.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	1514087
Time
Date	201801
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	RV-10
Operating Under FAR Part	Part 91
Flight Phase	Takeoff
Route In Use	None
Flight Plan	VFR
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Private Flight Crew Instrument
Experience	Flight Crew Last 90 Days 18 Flight Crew Total 409 Flight Crew Type 204
Events
Anomaly	Ground Event / Encounter Loss Of Aircraft Control Ground Event / Encounter Object Ground Excursion Runway

Rv-10 pilot reported losing directional control during the takeoff roll; consequently; the aircraft departed the paved runway surface and struck a taxiway sign and several lights.