VHF Com. Ant. for Biplane

Hello
A young friend of mine is in the process of restoring an EAA Biplane ,
last weekend we started working on his new engine mount , he started to
discuss the fact that he is installing his VHF Com. antenna inside the
fuselage , this experimental is the older tube and fabric design , cockpit
is about 24 in. wide and narrows to the tailpost , being an old HAM radio
operator , a lot of red flags went up , he want's to mount a standard 1/4
wave vertical somewhere aft of the cockpit area , width in the proposed spot
would be about 14 in. , all of my experience with radiating elements says
that it will not work , I think the element will try to couple with the tube
structure , SWR will go sky high and it will be a no go , I will bring an
MFJ 259 to the airport next weekend and try to give him a graphic demo. of
my perceived doubts .
I know that the guys with the glass and wood are doing OK with there
internal Ants. , wondering if someone else has had any luck with getting RF
to exit a 4130 airframe , he wants it to use in the standard 118- 136
portion on the band , plane has an alum. turtledeck , I told him that the
deck should make a good gnd. plane for the 1/4 wave vert. , he is concerned
about aesthetics , any thoughts would be appreciated .
Thanks
Phil
W8KLK