RE: p-51 mustang
Air retracts with funtional oleo struts is the way to go.
A simple search for "H9 AND Mustang" yields:
* [link=http://www.rcuniverse.com/forum/m_1726059/anchors_1726059/mpage_1/key_H9+AND+Mustang/anchor/tm.htm#1726059]Hangar 9 P-51 .60 size - RETRACTS[/link]
* [link=http://www.rcuniverse.com/forum/m_262704/anchors_262704/mpage_1/key_H9+AND+Mustang/anchor/tm.htm#262704]h9 p51 mustang[/link]
There are many more posts on the H9 Mustang. Do a search for them.