To me,water line CG is how it balances from top-bottom,like a boat in water or a car/SUV,SUV's are known to have a high CG,not too good for high speed turns-roll overs. An inverted mounted engine hangs the weight lower on the fuse which I believe helps in self righting,especially in upright harriers. Fore/aft and lateral CG still has to be set.

If you are not locating the tank over CG,you probably can run without a Cline or Perry pump,just follow the closed carb procedure to minimize flooding.(or use forceps to clamp the line)

The landing gear blocks do come loose quite easily,the formers come loose also. Just add some tri stock to the vertical formers and for further strength add hard balsa block or bass wood to join the 2 formers together. If any oil gets on the joints, it will soften the glue, you can coat the joints with epoxy thinned with isopropyl alcohol.You can reach inside to the gear block&formers thru the front of the wing saddle area.Dont be fooled by the tri-stock at the bottom and the 2 small dowels,they are not enough.


If you are not good at soldering and dont trust glue,use 4/40 all threads with carbon fiber tube glued to the threads,I like Gorilla glue for this,dont need much as it will expand inside the tube,you could just glue the ends & middle. Du Bro ball joints are probably best but I use Sullivan 4/40 metal ends with the little clip on keeper,I solder the clevis to the threaded rod on one end to keep the rod from rotating under vibration,I dont trust the 4/40 nuts to hold permanently.


I am on my 2d 60 UCD,have flown other peoples UCD too,none of them would harrier well,they didnt "lock in" for long and would snap out sometimes. I fixed this problem by Beveling the wing trailing edges using a Dremel tool sanding drum.The wing edges should be just like the aileron leading edge,tapered to 45 deg. angle. This will allow aileron travel above 45 deg. which is needed to completely stall that big fat airfoil that only fun-fly type planes have.To do harriers all day long if you want,you need "spoileron mix", which is elevator to flap/aileron mixing. The elevator is Master,ail/flap is Slave. When up elevator is pulled the "Spoilerons"(both left and right ailerons)go up also. I put this on a switch so I can shut it off when not needed. How much travel is needed requires some experimenting during flights.So you will need a computer radio with lots of mixing functions and some "open" mixes help too.You might be able to get the travel needed without beveling but the hinge gap will have to be wider than I like,either way,you should seal the hinge lines with clear Monokote or tape to help prevent flutter.