What's Included:

• 603 Series Retracts (4.0 oz less struts)
  
  
• Small air storage tank
  
  
• 1/8" wire struts
  
  
• 6 feet of air hose
  
  
• One way air fill valve with filler nipple
  
  
• Servo controlled actuation valve
  
  
• Air line Tee fittings
  
  
• Installation / operation manual
  
  

What's Not:

• Air pump
  
  
• Quick connect air fitting (for removable wings)
  

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Installation:

For the purpose of this review, I am going to walk you through the 603 Series retract installation in my Prince America Starship 46SS, an ARF type airplane with retract mounts already installed in the wing.

First step is to slip the retract into the mount, insert the wire strut and manually retract the gear. This can be accomplished easily by connecting your air pump directly to the retract and giving it a pump or two. Some slight bends in the strut were required before I could mark the location of the wheel. My wire bending tool made quick work of this.

Once I had the strut bent to fit the wing properly, I installed the strut back into the gear and marked the location of the 90 degree bend for the wheel. It is important to make sure you get this bend in the correct location in order for the wheel to fit properly in it's well. A good quality wire bender really helps with this process.

In the picture above and to the left you will also notice I soldered (silver solder) a retaining washer to the strut to avoid the wheel binding at the bend. This can also be accomplished by using a wheel collar but prefer the washer since it allows the wheel to be closer to the strut. Any excess wire can easily be cut off with a rotary tool and a cutting wheel. I placed the assembly back in the wing to check the fit.

When I have completed bending the strut to fit I duplicate the bends to the opposite side making sure to do them in mirror image. I then remove the struts and grind a flat spot into the shaft where the set screw secures the wire strut to the pivot block. This will also help prevent the strut from rotating in the retract.

With the struts completed and wheels installed, I then route the air line through the wing and attach it to the nipple on the retract, make sure you push the hose completely onto the nipple to avoid any air leaks.

With both retracts installed in the wing and screwed in place I proceeded to flip the wing over and install the "T" fitting to the air lines. Again, it is important to make sure the hose is pushed completely over the nipple to assure the air does not leak.

I then connected the air line to my hand pump and pressurized the system to check for air leaks and any binding of the gear. Any binding of the wheel in it's well should be corrected now. When air pressure is released from the system, the gear should immediately extend on their own.

Next, I found a location in the fuselage to install the air tank. From installations in the past, I have found the easiest way of holding the tank is place is with a product called Shoe Goo which can be found at most Walmart locations. A small bead of Shoe Goo is spread on the tank and then the tank is pressed into place in the fuse and held in place with either a block of foam or masking tape until the Goo has cured. Use of Shoe Goo will allow easy removal in the future by simply pulling on the tank.

The fill valve is installed by simply drilling a 1/4" hole in the side of the fuselage and using the provided nuts to secure it in place.

I had enough space left in the radio tray for the retract actuation servo. I simply drilled a hole in the radio tray to mount the control switch. A "T" fitting is used to connect the switch to the air canister and filler valve. The exit fitting on the side of the switch connects to the retract line installed earlier.

A mini servo was used to actuate the switch. The control linkage was bent from 1/16" piano wire. A small piece of air hose slid over the end of the wire will help retain the linkage from sliding off the switch. To set up your servo travel volume, reduce your ATV to 0%, center the servo horn and activate your gear switch. Dial in the amount of ATV required in each direction making sure you do not over travel the servo and cause it to stall!

Since the wing is removable on this airplane, I installed a quick connect fitting to the retract line. Just a simple twist of the connectors will lock/unlock the airline to the retracts and assure a leak free connection.

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Final Thoughts:
The new Spring Air 603 Series retracts were a perfect match for my Prince America "Starship". Installation was simple and straight forward. Their light weight frames are surprisingly rugged and the spring return feature works extremely well. The only downside to having this feature is the wing cannot be stored with the gear in the retracted position. The 603 series is just another addition to an already superb line of retract products Spring Air has produced over the years. Give Spring Air Products a try on your next project!

I give Spring Air Products 603 Series retracts a total of 5 out of 5 stars