Another Aviation Design Scorpion Build Thread

[pylonboy]

I know there has been a couple build threads already for the AD Scorpion, but I thought I might throw my hat into the ring on this one!

I got this plane a few months ago and have been slooowly doing a build in my odd spare hours.

First thing.....this is a nice kit! Well built and reasonably light. I have a couple friends with standard size Scorpions, and another with a Super Scorpion. All of them were happy with their planes, so I thought I might get one too!

I first started to assemble the horns and servos into the wing panels. The horns on this plane are quite deep and you have to make sure you don't cut too far into the bottom of the aileron or flap and cut through to the top of the panel! I measured the thickness at each area of the aileron and flap and made sure to cut just to the inner surface on the opposite side. This gave me the maximum strength and adhesion for the horns. I cut holes in lower portion of the horns for glue to seep through, and also roughed them up before gluing.

The gluing was done with Hysol and I masked the area off first to prevent glue from escaping the intended area. After the Hysol is partially set, but not firm, I remove the tape and let it settle to a smoother radius on it's own. This makes a relatively neat (for a sport plane) glue job of the horns.

[peter w h]

Hey Brent,

I Like it. What motor?

Peter.

[pylonboy]

JetsMunt 140xbl.

[pylonboy]

Here is one of the wing panels finished with the horn/servo install.

I did not use the factory hardware for the servo linkages which were 3mm. Instead I used Sullivan 4-40 clevises as they are a little beefier.

Not much room for any length of connectors as the clevises almost touch each other!!

Servos used throughout are Savox 1256tg digital coreless on the main surfaces. The rudders are using BlueBird BMS-390DMH as they require a mini servo. The system will be running on 5.9 volts through a Powerbox Baselog.

[pylonboy]

Anyone who has built a Scorpion must know that it is a bit of a PITA to install the elevator servos!!

My servos were a bit sloppy in the cutout, so I installed a sub-plate to mount them. I took ply and machined it to fit the original pocket. Basically it is keyed in and then glued with Hysol. Then all the linkages are matched side to side and installed. Very important to have the geometry exactly correct to ensure that the elevators move in sync with each other.

[bbdriver]

Looking good Brent.

[pylonboy]

Looking good Brent.

Thanks Sandro, this thread is behind the actual build.

Work gets in the way of my fun sometimes, but I hope to have it ready in a few weeks!

[pylonboy]

Next up is the landing gear install.

I decided to go with the Behotec 36 air retract system. Drop-in fit and durability. I have heard really good things about the electric systems too.

As it says...........just a simple drop-in fit. I went with Jetronics valves for actuation. No-loss Jetronic brake valve seems to work very nicely too. This is the first time trying this particular air brake valve, and it seems very proportional.

One really nice thing about the Scorpion is the landing gear is installed in the fuselage. Strength, less air connections when you put it together, and you can put the fuselage on the ground with the gear down and run up the turbine without installing the wings. Downside...............narrower stance on the mains.

[bbdriver]

Thanks Sandro, this thread is behind the actual build.

Work gets in the way of my fun sometimes, but I hope to have it ready in a few weeks!

YUP that 4 letter ugly word keeps getting in the way.

[pylonboy]

Next up is the airbrake. I have seen many flights of standard size Scorpions and Super Scorpions and the common theme is that you NEED an airbrake!

The instructions that I have from Ultimate Jets (I purchased the Scorpion from Peter at Altecare) show to use the round Hobart style hinges through blocks in the airbrake canopy. I looked at how Peter Woo's (Trevor Brum's now) Scorpion was done, and I decided to do a similar style installation. This allows for more travel of the airbrake if needed.

Offset hinges, mounting blocks for the hinges, mounting blocks for the cylinder/actuator and stops for the travel are all required. I also decided to go with a Firgelli actuator 100mm long with a 100:1 ratio for operating the airbrake. Nice speed and plenty of power. After the installation, everything fits nice and snug!