It works at my pc this way:
.h
GENERATED_BODY()
UPROPERTY(VisibleAnywhere, BlueprintReadOnly, Category = Helicopter, meta = (AllowPrivateAccess = "true"))
USceneComponent* SceneComponent;
public:
// Sets default values for this pawn's properties
AMyPawn();
.cpp
SceneComponent = CreateDefaultSubobject<USceneComponent>(TEXT("SceneComp"));
SetRootComponent(SceneComponent);