CAD Project - 3D Printed Taildragger Landing Gear With Shock Absorption

BayDesigns

Active member
Hey! I'm working on a lightweight hinged taildragger landing gear system to be installed on RC aircraft- it's intended for smaller planes- it'll probably take a maximum 3-inch wheel, but it's still in early stages, plus, you're free to scale it up. Once I actually test it, I'll make it available for your use! Just to give you an idea of how it'll work, there will be a central piece attached to the fuselage. This part has mount points for a hinge on both sides, and the gear struts will hang from those. The gear struts themselves will be roughly 4 inches long (at this point in development, I will almost certainly change this), and they'll have attachment points for 2 shock-absorbing options- they can either be held to each other, or they can be attached independently to a central point on the main plate. The actual shock absorbers themselves will be rubber bands- Eclipson inspired me with their trailing-link style gear, but there wasn't a cheap bungee option for taildraggers that I knew of- this one will be free! The end goal for weight is for the printed parts to be under 20 grams, and currently, the estimated weight is 17 grams. The all-up weight will be somewhat higher, since I'm not including bands, wheels, and screws or other fasteners, because those parts will vary from model to model. However, the end product will be a low-to-no-cost, lightweight product that should be able to take a beating and move on. I love flying, but I hate breaking things and having to wait for new parts to be delivered or printed, so rest assured, this will be a quality product. And if it does break, it's not like you need to pay to replace it! Ultimately, this project will protect your airplane, whether you fly STOL or aerobatics!
 

BayDesigns

Active member
Yep, I’m working on it. At the moment I have several projects going on plus school. It’s not gonna be long.
 

BayDesigns

Active member
@quorneng I'll have some pictures of the design soon!
An update for the current weight of the printed parts (that's all I'm going to estimate, because I will RECOMMEND certain parts, but everyone's setup will have a slightly different weight): the total weight is just a little over 9 grams! In the end, I think I may have to lengthen the gear legs, but I think that the total weight will be less than 75% of the projected weight.
 

Dudley1001

Member
I found these a couple of weeks ago and have been using them on my STOL Buschtrottel and they fit and work well. I would like to see your design to see if it will be lighter. I didn't have any 4mm carbon so used 4mm wood dowel from $store. https://www.thingiverse.com/thing:3603111
 

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BayDesigns

Active member
Here's the (probably way over-engineered) Main Gear Truss. This one's probably the closest to the final state of things, but if A) someone makes a good point, or B) if in the course of testing I find an issue, I may change it. I'll just be adding band attachments to the cross-pieces. Limiters will also be added to restrict the downward movement of the legs.
MGT Mk1.PNG

And here's the Main Gear Leg. It's designed so you can print 2 of the same piece (mostly so my lazy self doesn't have to make a reverse version :). This one's probably going to be re-done soon, I'll be moving the band attachment points to the other side and moving it further down the leg, since I think a bit more leverage will be good.
MGL Mk1.PNG

Work will soon begin on the tail piece!
This project is designed with flat-bottomed aircraft in mind, but for me personally, I'll be modifying the pieces so that they curve with the fuselage of the Model A.
 

BayDesigns

Active member
Here's the tail mount point! The band post is the part on the upper left. I'm working on the tail arm now, and it should be done soon! Next, I'll be putting band posts on the main gear truss and moving the main gear leg posts to get a more useful position. After I finish these parts, I'll try to run them through SimScale for both aerodynamic and mechanical strength analysis. I won't be able to get rid of all the drag, but if there's a ridiculous amount at some location, I can hopefully get rid of some of it. I'll also be strengthening locations that look weak.
TMP Mk1.png
 

BayDesigns

Active member
After a CFD run of the main gear truss with astonishingly bad results, I'm redesigning that part to offer a bit less drag, so here's a look at Mk2!
MGT Mk2.PNG
 

BayDesigns

Active member
After 2 more runs through SimScale, it turns out that the above design produced a large reduction in drag! Dragging landing gear through the air is always going to create drag, but at least it's minimized!
 

BayDesigns

Active member
Hey, for all the people watching this project, it's going on hold. Sorry. I'm not giving up on it, and I plan to make it available eventually, but I can't really work on it for now. I'm getting serious about taking real-life flying lessons, and I need to make some money for that, so I'm working on developing CAD models to be sold online in the near-ish future. Because of this, I'm spending a lot of my spare time on getting a variety of models prepared for testing. Rest assured, however, that this project will continue once I'm happy with the stuff I'm doing now.