For the telescoping strut idea, you may want to contact Bill Kelly at Northwest Dynamics (360)253-3656. They've been involved with several landing gear developments over the years and were the producers of landing gear components for sevral experimental and certified aircraft. About a year ago Bill developed an idea for a telescoping Oleo sytem for one of his customers. I'm not sure I have the details any more but they'll be the ones to talk to.
I think Northwest does production, not consulting. They also do traditional single telescoping Oleos, which is not what I am doing. No web page. Not interested.
As usual, my design may require a double telescoping Olea, and better yet a tripple. The main Oleo is 4.5 inch diameter with a 12.25-15 inch stroke and the subsequent inner telescopes are hydraulic with a 12.25 and 7 inch strokes. It is pure axial with no side loading so it can be very light.
What I am after is someone with an open mind that knows hydraulics enough to point out some of the pitfalls that may be there. I have a hangar partner that used to work at Parker in hydraulics, but he is too busy setting up Subway restaurants to be bothered, and he is a management type.
A classical design will never get the weight and utility saving I am looking for.
So, the question is: Have you ever seen a double or trible telescoping Oleo strut with one main air chamber and the rest hydraulic?
Northwest Dynamics does do consulting as the design I mentioned is actually their own. The telescoping idea was developed for a customer who needed a longer gear for clearance but did not have a lot of room for retraction. The mechanism allowed for the gear to get shorter before it retracted into its available cavity.
True, their primary function is manufacturing, but personally I like that since their experience can identify practical fabrication difficulties prior to initiation of actual production.
However, I do not remember whether their design was was a double telescope or triple, nor do I remember the layout of the cavity nor how many chambers it incorporated. I'll dig though my drawing files and see if I have the design around. If I do I'll post a subsequent note.
I would hazard a guess that the length change feature was just added on the tire end of the strut as a hydraulic rod to which the tire is secured. A classical Oleo strut with all the internals would work fine.
What I need is to do is to use the area for a hydraulic that is typically used for the dampening pins and orifices. This would require a new orifice design that would shut the fluid along the sides, perhaps, instead of down the center where the hydraulic must go.
I have not found any designs that would work for what I want to do, or which I can draw inpiration from. Leading edge has nice shock they sell (http://www.leadingedgeaircraft.com/ipl.htm) but it would be too long in concept with a hydraulic down the center. There are a lot of utility, system and safety advantages if I can get it to work.
Maybe I need to turn it around and go with the hydraylic on the outside of the Oleo ram instead of a classical telescope with smaller and smaller rods.
The telescoping system for the strut was actually at the top. The bottom was a standard Oleo setup. The sliding mechanism and actuation was all done on the upper part so as to minimize possible slop that could be introduced by lengthening the piston and scissor mechanism.
For a custom design, you may want to look at several of the organizations that provide shock and Oleo systems for custom applications such as off-road racing vehicles. I just had a customer who was looking for a custom shock absorber for his new bush-plane idea. In the end we actually didn't use the concept but his search did lead him to several of these organizations that he indicated were capable of delivering pretty much anything he could think of.