Analysis of longitudinal static and dynamic stability for commuter floatplane

Tema ovog diplomskog rada je analiza statičke i dinamičke uzdužne s tabilnosti putničkog hidroaviona nalik na DHC-6. Za provedbu te analize potrebno je odrediti uzdužni aerodinamički model te su metodom projektne aerodinamike određeni koeficijenti otpora, uzgona i momenta propinjanja za svaki segment konfiguracije te ukupni stacionarni i nestacionarni koeficijenti. U aerodinamički model je uključen i utjecaj plovaka, a u opisu ukupne normalne sile i momenta propinjanja uključen je i utjecaj motora. Nakon toga analiziran je ravnotežni horizontalni let i utjecaj promjene mase i položaja težišta na ravnotežne kutove otklona kormila visine i ravnotežnog napadnog kuta . Također su ispitani uvjeti uzdužne statičke stabilnosti te određena neutralna točka. Za analizu dinamičke stabilnosti određeno je nekoliko karakterističnih linearnih modela obzirom na masu, položaj težišta i brzinu krstarenja. Zatim je provedena usporedba njihovih modova uzdužnog gibanja te odziv na dvije pobude u vremenskoj domeni. U zadnjem poglavlju provedena je ocjena kvalitete direktnog upravljanja za analizirane linearne modele u horizontalnom letu prema MIL, ICAO, ESDU i CAP kriterijima.The subject of this master's thesis is the static and the dynamic longitudinal stability analysis of the commuter floatplane similar to DHC-6. In order to define longitudinal aerodynamic model, the drag, lift and pitching moment coefficients were estimated for each configuration segment and stationary and nonstationary total coefficients as well. Influence of the floats was included in the aerodynamic model and influence of the propulsion system was taken into account for the calculation of total normal force and pitching moment. The horizontal steady flight was analyzed, as well as the influence of the variation of the weight and center of gravitiy position on the elevator trim deflections and angles of attack. The static longitudinal stability conditions and neutral point were also examined. For dynamic longitudinal stability analysis several characteristic linear models were defined considering different weights, center of gravity positions and cruise speeds. Their longitudinal modes and time response due to two different control inputs were compared. Flying and handling qualities based on MIL, ICAO, ESDU and CAP criteria were examined in the last chapter of this thesis for different horizontal linear models