! LaTeX Error: Illegal character in array arg. appeared while executing the .tex code for Table

Question

When I tried to run tex code to generate table, I encountered the error stating that

! LaTeX Error: Illegal character in array arg.

And The code goes like this. How can I fix this error?

%Table
\begin{table}
\caption{Drag Breakdown - Component method}
\label{table:PWDT}
\centering
\small
\renewcommand{\arraystretch}{1.25}
\begin{tabular}{1 1 1 1 1} 
\hline\hline
\multicolumn{1}{c}\textbf{Components} &
\multicolumn{1}{c}\textbf{C${}_{d-sf}$} &
\multicolumn{1}{c}\textbf{C${}_{do}$} &
\multicolumn{1}{c}\textbf{C${}_{di}$} &
\multicolumn{1}{c}\textbf{C${}_{D}$} \\
\multicolumn{1}{c}{(1)} &
\multicolumn{1}{c}{(2)} &
\multicolumn{1}{c}{(3)} &
\multicolumn{1}{c}{(4)} &
\multicolumn{1}{c}{(5)} \\
\hline
Wing & 0.1 & 0.2 & 0.3 & 0.4 \\
\hline
\multicolumn{2}{l} {} \\
\hline\hline
\end{tabular}
\normalsize
\end{table}

Tried to check column and symbols.