Titanium Struts — an Explanation

When Central Hobbies first began offering titanium struts, a lot of pattern pilots were curious as to why they might want to use them, and whether or not the extra cost is justified.  And we get still the same question from pilots who are looking for ways to improve performance and stability.

The answer depends on your aircraft and your style.

We sell Great Planes and Robart retracts.  Both kits are dependable and widely used on pattern planes.  With sturdy molded base, a locking mechanism that is very secure and low installation profile, these are excellent retracts. They come with 5/32" steel struts. For virtually all 60 and 90 size planes and the smaller 1.20/1.40 planes they are a good choice.

But there are times when the 5/32" steel struts are not enough. As pattern planes have evolved, several factors have contributed to the need for more substantial struts. Those factors include:

• Higher wing locations

• Higher weights of the newer 2-meter aircraft

• More powerful engines that turn larger diameter props (16-17" diameter vs. the old 12" - 13" standards)

As a rule of thumb, titanium has only three fifths the weight of the steel used in steel struts.  So if your steel struts weigh in at 60 grams a pair (roughly 2.12 ounces), you can cut 24 grams off the gross weight of your plane by simply switching to titanium struts of the same diameter and length.  Yet, while saving weight, you also add a lot of durability and strength to the landing gear.

Obviously the higher weights put more load on the struts. But even more significant are wing location and prop diameter: both are factors that require LONGER struts.  As you extend the standard 5/32" wire struts beyond a length of 7-8 inches, they become too spindly and bend too easily.

You could simply modify the standard Great Planes units to accept 3/16" music wire struts. However, the added weight of longer and larger struts is significant. Also, 3/16" music wire may actually be too stiff, increasing the chance of inadvertent gear plate removal.

So, enter the titanium strut. Made from Titanium alloy, at full length the struts are lighter than the much shorter standard struts, and offer better rigidity. They also tend to bend further WITHOUT taking a permanent "set" requiring re-bending.  For the larger planes and props, these struts offer the support and clearance needed with lower weight than the shorter standard struts. 

You may also want to consider building your aircraft to accept the larger -- 2-3/4" to 3" -- wheels to further enhance the ground handling of your aircraft and allow slightly shorter struts.

Are there any negative aspects to the titanium struts?

In a word, yes.

Titanium is expensive material and is also more demanding to work and machine. These factors make titanium struts more expensive than music wire.  Also, if there are defects in a strut, or with a very hard impact, the struts may still break.  We've had a total of three strut failures reported to us in the entire time we've been selling titanium struts (to hundreds of pilots all around the world).