I have been thinking about this for the last few years, and the Just Aircraft Super Stol thread has brought this subject to the forefront. What is possible with an Off Airport airplane if we had better suspension? Big aired down bushwheels do a good job of soaking things up, but what about when I want to land a logging road with a water bar cut in it, or a gravel bar that has a ditch from a stream running through the middle of it? When I am riding or driving offroad in the desert, I usually find myself wondering if I could land different sections of the trail, but many times, the ground is just to rough. One or two bumps, or whoops would be fine, but what about a 150ft section of 12-18" tall bumps? Or how about just soaking up a bad landing without a bounce resulting?

Just aircraft, the RAGE suspension, AOSS, etc have been toying with dampened suspension and this is interesting to me, but why is everyone hanging it out in the wind? Road race cars have been using pushrod suspension for years to keep the shocks out of the airstream and package them in a more centralized location for weight distribution. It seems that this would be possible with an airplane in the seat truss etc. and still be able to achieve "long travel" and highly adjustable dampening for a bushplane.

There is a lot of R&D that goes into every one of these cars to make them handle at speed in the rough. Airplanes wouldn't have the issue of building heat in the shocks because they should only be on the ground a few hundred feet at a time, so the shocks could be smaller/lighter and hold a lot less oil.

Other than approach angle of the tire to an obstacle, could we get the same performance out of 31" tires as we get with 35's if we had better suspension travel and dampening? Or is there another factor????



A basic example of pushrod suspension.

I think it is an issue of weight and drag. Those long travel shocks and big fat tires come with substantial amounts of both. Fine if you are looking for a purpose built limited use aircraft. Nothing remotely new there. The Just is a complete copy of the Feisler Storch of WWII vintage and that was an improvement over previous similar designs. Sure the technology has improved but most of the improvements are in weight. The drag is still limiting.
I give Just aircraft credit for tooling up production on a high dollar, low demand aircraft. Realistically how many do you think they will sell? The cool factor is off the scale but how many of us can use it in their average everyday flying?
There were a couple of replica Storch aircraft but neither sold more than a few units.
The Rage is much more main stream and I suspect it will be far more successful in terms of units sold. (my S-7 will have one someday)
Given that there are flying cars, it is not unreasonable to envision a flying ATV. But to what end other than novelty?
I applaude the drive to create a better suspension but with the every growing threat to our sport by the environmentalists I fear that the ability to benefit from off-road capabilities is shrinking.
If I ever find one of these for sale, I will buy it.

Highroad, I think you are on to something...

Not just suspension either, the auto racing industry spends millions in research and development around three things, speed (obviously), weight and safety, the very things we look for in a great aircraft. They study fluid dynamics as intensly as an aeronautical engineer.

I've often daydreamed about what I could incorporate in an experimental aircraft. Your example of pulling much of the landing gear "inside" the fusilage is a great idea. I've also seen racers hit a wall at 160+ mph and walk away so the development of a carbon fiber "tub" around pilot and passengers is interesting to me.

interesting topic.

For the most part GA is sewn up by older guys getting ready to or who are retired (and they are looking to "protect" thier investment not go out and take a chance on balling it up). There are not that many (in reality) younger more adventurous people with a pocket full of money to burn on the latest and greatest bad ass bush bird to come out. That is not at all to say that there are not a few of the older guys out there that will do shit that I think is frickin insane in a plane, but they are the exception, not the rule. The same as folks in the younger age group. There are a few here and there but they are far and few between. Until the 25-40 crowd are not spending damn near every dime they make trying to raise a family and make basic ends meet, then I dont see too many aircraft manufactures spending what it takes to research and develope new super suspension systems just to sell a couple of them a year.

All that being said, I LOVE the fact that some guys are making improvements and doing things I have thought about for years (like the rage system) but I also hope that they really test this stuff out before marketing it. Kind of like the new "bush gear" that Avid and Kitfox and a few others are making. ( cabane "cub" type spring suspention instead of the old wrapped bungees)... While it seems to work REALLY well on improved strips, it seems the loads it puts on the fuse were not really acounted for and it is buckling the fuse now on rough landings. Not enough R&D was done prior to releasing this "new" product to market. But I guess that is how the experimental world works!

I have had a rage system suspension on my highlander for about 10 hrs and 50 landings. If you are familiar with with the stock system on a highlander, you would know that it can bounce beyond your imagination if you dont get your landing spot on. With the new Rage system, you can drop it in hard and have very little rebound, if you change your load, you can add a little air or remove a little and you have infinite possibilities for adjustment. It is built tough and the welds are very high quality. I do not have any rough fields here in fl to try it out on, but the few bumps I have encountered are certainly less severe than before. It appears to have 8-10 inches of travel with the bungee assisted gas/air shock. So far I am very satisfied with the performance. It has changed how I approach my landings now that I do not have to consider coping with a wildly bouncing nearly out of control aircraft. pm me if you have questions and I will give you my phone numb er. RLM

I think the limitations are largely about money and prevailing best practices in the field. I think a practical controls theory guy can make an active system do what you ask...but control theory looks like sanskrit to most folks in mechanical disciplines...which is a shame.

I've had discussions with suspension specialists from the racing world and heavy vehicle world, and there was a 100% disconnect with control theory beyond a very simplistic, textbook level at best. I think there might be potential if there was a pool of folks lined up to drop several thousand dollars in parts (completely experimental class, of course) plus profit for dozens of systems, while adding significant weight. Otherwise, I think it might be challenging to justify.

There are still basic limits as well (approach angles,etc, as mentioned) that really can only be addressed by an active system unless some seriously clever alternative is planned.

So- how much would how many people spend? That is the question...