user: You are a structured reasoning expert tasked with solving problems step by step. 
You first think about the reasoning process in the mind and then provide the answer. The reasoning process and answer should be enclosed within <think> </think> and <answer> </answer> tags, respectively, i.e., <think> reasoning process here </think> <answer> answer here </answer>. 
Given a question and the associated knowledge graph triplets (entity, relation, entity), you are asked to answer the question with these triplets and your own knowledge. 
You can break down the original question into several sub-questions and explore the given knowledge graph to solve them step-by-step. If there are multiple possible answers, choose one as the final answer. 
After thinking, when you finally reach a conclusion, clearly state the answer within <answer> </answer> tags, i.e., <answer> answer here </answer>. 
Question: which aircraft model is of the experimental vtol fighter aircraft type? 
Knowledge Triplets: Convair XFY Pogo, base.schemastaging.aircraft_model_extra.manufacturers_empty_weight, 5310.0
Convair XFY Pogo, aviation.aircraft_model.passengers, m.0x0nl4_
m.02hvzcw, aviation.aircraft_ownership_count.aircraft_model, Convair XFY Pogo
Convair XFY Pogo, aviation.aircraft_model.aircraft_type, Fighter aircraft
Convair XFY Pogo, aviation.aircraft_model.cruise_speed, 640.0
m.0fs6p7s, aviation.comparable_aircraft_relationship.aircraft, Convair XFY Pogo
Convair XFY Pogo, aviation.aircraft_model.aircraft_type, Experimental VTOL fighter aircraft
Convair XFY Pogo, aviation.aircraft_model.maximum_speed_km_h, 981.69984
Convair XFY Pogo, aviation.aircraft_model.number_owned_by, m.02hvzcw
Fighter aircraft, aviation.aircraft_type.aircraft_of_this_type, Convair XFY Pogo
m.04cp9jh, aviation.comparable_aircraft_relationship.aircraft, Convair XFY Pogo
Convair XFY Pogo, aviation.aircraft_model.maiden_flight, 1954-11
Convair XFY Pogo, aviation.aircraft_model.manufacturer, Convair
Convair, aviation.aircraft_manufacturer.aircraft_models_made, Convair XFY Pogo
m.04cprsz, aviation.comparable_aircraft_relationship.aircraft, Convair XFY Pogo
Convair XFY Pogo, aviation.aircraft_model.comparable_aircraft, m.04cp9jh
m.0h7kr5v, dataworld.gardening_hint.last_referenced_by, Convair XFY Pogo
Convair XFY Pogo, aviation.aircraft_model.comparable_aircraft, m.0fs6p7s
Convair XFY Pogo, aviation.aircraft_model.wingspan, 8.43
Experimental VTOL fighter aircraft, aviation.aircraft_type.aircraft_of_this_type, Convair XFY Pogo
Convair XFY Pogo, aviation.aircraft_model.length_meters, 10.66
Convair XFY Pogo, user.avh.default_domain.ellerdale_topic.ellerdale_id, 009e-14b1
Convair XFY Pogo, aviation.aircraft_model.range, 640.0
Convair XFY Pogo, aviation.aircraft_model.comparable_aircraft, m.04cprsz
Convair XFY Pogo, aviation.aircraft_model.engine_type, Allison YT40

Answer: Convair XFY Pogo