How to build jacks for your Navion

Jacking a Navion is necessary at least once a year for performing gear swing tests during an annual inspection, but can also be needed any time you may need to do maintenance on the undercarriage, brakes, or tires.

According to the service manual, jacking the Navion is done by placing jacks under the tie-down rings under each wing and using a tail stand. The requirements for each are :

Wing Jack

• Supports at least 1,500 lbs
• Minimum height 27″
• Extension 15″

Tail Stand

• Able to support 200 lbs

 

However, I’ve found that in practice, wing jacks can be up to 34″ tall and fit, and you probably need a minimum of at least 7″ of extension. Tail stands work best when they orient the airplane approximately like level flight, and that works out to be between 33 – 36″ tall. 

Aircraft jacks are kind of pricey, with the cheaper ones starting at around $400 a piece, and jacks that were appropriately sized for the Navion were a bit hard to find. I definitely didn’t want to use something sub-standard, but I also didn’t feel like the going price was justified, so I decided to build my own.

My goal was to use as many off-the-shelf parts as possible, keep costs reasonable, and have the end result meet or exceed requirements by a healthy margin. Here’s what I came up with for the wing jacks:

Parts List

• 2 Sunex 1410 10 Ton High Height Jack Stands – sold as a set of two (2) for ~$230
  • For other aircraft, such as a Bonanza, Mooney or Arrow, which are a bit lower to the ground than the Navion, Sunex has a similar Low and Medium height versions of the same jack stands.
• 1 Mophorn 1/2″-12″ V-Head Pipe Stand (28-52 inch height) for the tail stand ~$100
• 2 long ram 3-8 ton hydraulic jacks with flat bottom. There are several options here, and any of them will work, the key is that the barrel of the jack must be no bigger than 3″.
  • Strongway Hydraulic Long Ram Jack – 3-Ton Capacity Flat Base ~ $60
  • Sunex 5041B 4-Ton, Long Ram Jack ~$100
  • Central Hydraulics 3 Ton Heavy Duty Long Ram Flat Bottom Jack  ~$50
• 2 Grade 8 5/8″ x 2″ bolts, with nylock nuts (from the local Ace hardware)
• 2 pieces of 5″x 2″channel steel approximately 14″ in length each (sourced from a local steel supplier) cost ~ $10 per piece

Total cost :  ~$460 for the entire set

 

Assembly

1. First order of business is to toss the center steel posts which come with the jack stands – you won’t need them. My initial plan had been to place the jacks on the ground and have the jack push up the post, but I found this to be way too unstable. You need the weight of the aircraft transferred to the legs of the jack stand for stability.
2. Test fit your long ram jacks into the jack stand legs. The center hole is 3″ in diameter, and given the thick coats of enamel on both the legs and the jacks, it may be a very tight fit. In my case, I wound up removing the paint on the legs, and widening the opening with a grinder a bit so that the jack fit snugly through both holes. If you purchase the Strongway jacks above, they are slightly less than 3″ in diameter, and you might be able to avoid the grinding, but I prefer the tighter fit for increased stability.
3. When fitting your jacks into the legs, be mindful to remove the dust cap over the fill hole of the jack, or you may soon have need to replace it.
4. Cut the channel steel into 14″ lengths, if the steel shop didn’t already cut them for you. Place the steel across the leg supports. Mark where the 1/2″ leg supports intersect the steel, and cut 1/2″ wide notches so that the flat of the channel rests on the cross-supports. I also trimmed the corners so there is less material hanging down. When you’re finished, it should look like so :
   
5. Slide the jack into the legs, and then place the channel steel over the leg supports, and push the jack down so that it is flat on the steel. Put the 5/8 inch bolt through the end of the jack (this will go through the tie-down ring when jacking). When you’re done, it will look like so.
   

Notes

1. Because of the way the leg support rail is welded to the legs, it’s primarily designed to keep the legs from spreading, and is not designed to hold up a vertical strain. Granted, these are 10 ton jack stands, so an 1900 lb airplane won’t likely be a problem, but it would never hurt to stuff an appropriately sized block of wood under the channel steel just for added safety.
2. Make sure the tail stand’s legs are oriented in a way that it won’t potentially tip backwards while jacking up the airplane.