Parrthd

Vaccum sheeting the wings in this build is refering to apply the balsa sheet to the foam core wings under vaccum. This ables one to use much less epoxy resin compered to regular sheeting technique, and to avoid any possible bubble formations meaning parts of the sheet that did not glue down properly to the foam core. Hence a better and much lighter weight (several ounces) end result.

Considering you have a 27% plane and are going for a gas engine I would like to have it glassed. However, as I recently found out when I was asking and doing research about glassing for my plane, there is skills and a lot of work into getting a good fiber glassed model. If done properly and correctly this is the way to go as it has superior finish and is only then as light as balsa sheeted foam core wing with plastic film. If you dont have these skills, including excellent painting skills, or does not knowing anyone that have done successfull jobs previously that could help you I would cover it with plastic film as in my case. Also one needs a proper workshop for glassing. Having this said, I think most CA Extra's out there is covered with plastic covering. If one does not have the meantioned skills it would be wise to learn the techiniqe before attamting such a nice model as the 27% CA Extra.

Im thinking to use Hitech digital HS-5645 all around on this plane (169 oz/6 V system) as they are affordable and has good performance but have not decided yet. However I will not use anything less than 100 oz servos on this 1/4 scale. Perhaps you should go for 130 oz? While on rudder I will follow the old saying "use as powerfull as the planes weight" wich has been proven great for me so far. This would translate to a 11 lbs plane to have a 176 oz rudder servo, or a 14 lbs plane 224 oz. I could accept dull servos on the ailerons and elevator if needed but not on the rudder. This is my opinion.

I plan to use a 1500 mAh Lipo battery running 6 decent servos. If you have all high tourqe servos and perhaps more than 6 servos I think using 2000 mAh is a good idea but not any bigger unless you want more than perhaps 6 flights without recharging. You will also need to think about your all up weight and to prioritice what you want out of your plane.