Catalina wings on a Mk4

[Aaronavid 0]

Hi folks.  Its been many years (and two other projects) since i last flew my Mk4 Speedwing and I have decided to get it flying again!  I have a set of Catalina wings that I am finishing off to turn the plane into a super STOL machine.  Each Catalina wing panel is 15' long compared with the HH panel at 12' long.  The normal avid wingtip adds another 18" per side to make the HH wing 30' overall wingspan and the Catalina 36'   My thinking is that i will not add the large wingtips and just put end-plates on the tips so my wingspan will end up at 33'.  Aside from the extra 3' in wingspan, the only other difference is that the lift struts are mounted further outboard and, obviously, the flapperons are longer.  So I think this will work out pretty well but I'm interested in your thoughts about whether there is enough tail volume to give me sufficent control and stability.  I havent done the tail volume calculations yet but plan to.  I dont want to have to modify the stabilizer if i dont need to.  

Do you guys have any thoughts about how well this will work and any other considerations? 

Two other quick questions - (1) I have the old fiberglass wing tanks and dont plan to use ethanol. Any problems with those?  (2) what do you use as guages for fuel level (sight tubes?) 

Thanks in advance.  Nice to be back!

Allan (Sydney) 

AVIDMK4, MustangII, Safari Helicopter, Cozy Mk4 (still building) 

[flywise 169]

Hey Allan,

I fly the Catalina with original fibreglass tanks. I use non ethanol fuel and it's working fine. For the fuel level, I have a section of fibreglass from the tank visible (not painted over) in the cabin showing me the fuel level in flight.

These wings give a lot of lift for sure...

[ChrisBolkan 130]

If my Catalina project turns out to be a bust (i suspect it will be fine) I have fantasized about how cool it would be to put the wings on my Fat Avid.

[Aaronavid 0]

So I got the wings fitted today. It all lines up well and the dihedral and washout are identical. I need to drill / ream the holes in the spars now. One issue is that the Catalina wing struts are longer and therefore mounted further outboard. So you can't fold the wings all the way back because the struts interfere with the stab. I guess if I don't have enough tail area I could just extend the fuselage about 6".  Something to think about later... 

[Aaronavid 0]

Oh and tanks for the feedback on the tanks!