DESIGNING A NEW KITFOX SHOCK GEAR - PART 01 🛩🔧⚙ 

Guys. What an overwhelmingly positive feedback from all of you. Thank you. I didn't expect so many comments and questions. I will do my best to keep you all posted and up to date during the installation and test progress. I loved the design part and if this turns out to be a solution to a problem, I've done my job. cheers!!

As a retired aircraft structural analyst from Lockheed, I can say that I'm glad someone is out there with new gear shock systems that are low drag. Your's is basically a small automotive "4 link" suspension. It's not clear from these pictures how the connections are being made at the end of each link to prevent the 'heel toe' reaction at each of these connections generated by the guided cantilever bending moments. The overall design may be more than capable of reacting the loads you've applied, but the very high bending loads at the connections must also be considered. Also the 4 link suspension that is very well proven normally has an "A" shape so that the over turning loads are more reacted as tension and compression rather than a lot of bending. Also, maybe not a problem here, at least short term. is 7075-T6. This material has not been used on any military and most civilian airliner aircraft in the last 20 years due to it's intergranular stress corrosion cracking tendency over longer periods of time. Use T753 or similar to avoid this problem.

Can’t wait to see how it works out!

Great to see some technical talk and modifications as part of a persons posts.

So cool! Love that you are thinking outside the box.

Thanks for taking us through your thinking and design concepts so that it's easier to appreciate your final product. Looking forward to Part II.

I don't even own an airplane, though, watching Trent Palmer's amazing videos made the youtube algorithm bring me here and I am glad!!! I am a mech engineer undergrad and interest in mechanics made me love this video. Hat's off to you sir, looks like a sweet design!!! I like how you explain the whole process of starting with a design and then improving on it, the process is what makes it enjoyable!

It might work great but you're not kidding anyone about the aerodynamics!

Brilliant. Simply brilliant.

I am checking in every single day for part 2. Very interesting!

Very cool Alex, I can't wait to see the next vlog...

I really like this solution, it's much more elegant than the cabane gear.

Nice presentation. I use Super Cub style gear myself, with bungees and a Fox air shock to help control rebound, everything faired. One thing about any gear drag, is it can also translate into trim drag, as the extra drag is as far below the plane as it can get. Your drag calculations may be a bit optimistic, I'll hazard a guess: 5 to 7 mph off your normal cruise speed.

I think you knocked this one out of the park with that design. I look forward to flight testing and evaluation in real world applications. Congratulations on a great invention. As a suggestion, seeing as you are using pressurized shocks. How about using adjustable pressurized shocks, so they can be field changeable to account for differing loads and expected landing conditions.

Very good idea. Can't wait to see the test flight!

ok..here we go.. Mike Patey Jr. love your content.

Mike Patey is designing a new system that puts the shocks inside the plane, out of the wind.

Clever design; should make for an easily tuned two-stage suspension system.

Looks real promising can't wait to see the real world testing ,GOOD LUCK

Very interesting. Im impressedwith all the thought and planning

Alex, I love the way your mind works. Very well thought out. I will be looking forward to part 2.

Pretty awesome! A lot criteria to meet, interesting ideas as you went.

Thank you for showing your improvements I look forward to seeing more about this new shock setup best of luck to you

KICK. ASS. Brilliant design and engineering proof. Can't wait to see the flight test series!

Very cool. Looking forward to the next video.

Wow! I'm very impressed. Great great idea. I would think this should be standard equipment.

wow.. nice job, plug n play makes this sound necessary for kitfox owners

Good idea Alex....

Good job Alex. Although I don't have the Grove Gear on my Kitfox 5, I'm looking forward to seeing how your design works on yours. Good luck for positive results.

Looks very good, nicely engineered. Best of Luck on the test flying.

Well done, Alex! Very impressive, I’m sold on your endeavours, wingman. I’m sure I’m not alone in saying, I’ll be watching your progress closely. 😉 Thank you for sharing.

Awesome Alex,, Keep us informed!! Am excited to see next video!!

Awesome job! Hopefully patent and get it commercially produced. Best of luck with a great idea.

Another excellent video from a cowboy. Wish you well with the new main gear. Of course it will place a longer lever against the fulcrum of the leaf spring original gear. Probably not significant given the weights you are using. Looking forward to the results.

Alex, great job. Way to think outside of the box.

Great video!

Alex this is awesome. Love engineering and building my own stuff... so it's very cool to see you doing this.

Love the idea, love the video. Great to see other inventor-types doing creative work to advance bush flying. I just ordered a small airplane that holds the wheels in a very similar manner... though I think the piece that bolts to the bottom of the airplane is carbon fiber instead of metal. Nonetheless, if your idea works, it might work great for me too, since I'm planning to do a lot of bush flying too. Awesome.

Nice job Alex! Can’t wait to see your tests

Outstanding! Looking forward to seeing it at work.

Beautiful CNC machined components!!. awesome design

You are forgetting that the existing strut acts as a spring. Your dampers don't do anything to absorb that energy, and the extra leverage will reduce the spring rate and possibly overload the strut or its connection to the fuselage. Engineering tools and terminology doesn't always correlate with good engineering.

I have a kitfox 4 in New Zealand with a hammer head gear Same as grove except it's made From 7075, instead of the grove Gears 6061 alloy. It's very strong but will bounce very easily on rough strips or any landing that You don't greeze it on, which can be quite a pain. Very interested to See how this works.

Brilliant.

Excellent idea! Best of luck Alex!! :)

That looks so epic!!

Well done. This us great content.

Very interesting Alex!

Way cool! Great job

Cool project. Can't wait to see the testing videos. Subbed....

Looks awesome

very innovative. good job

Great job Alex! If your design proves to be a viable solution, I can foresee how you may be able to easily adapt it to many other airplanes with similar landing gear. Best of luck.

coefficient of drag is only part of the equation, the surface area also increases. Though it's probably not as big a difference as going from small wheels to big wheels.

look at the off road racing cars and trucks long travel shocks. smooth landings ahead!!!

Awesome......I can't wait to see it in action. My Kitfox V with the Grove gear could use a little more give on those backcountry excursions.

damn great idea, looking forward to the vid's

So we had some members of an engineering team use the in CAD simulation (which is why it looked like was used here) they had results that validated the design choices. During the build and test phase the parts failed when they should have survived. Another member in the team reran the simulation on ANSYS and found that it would fail which matches the real data. Since this is a vital part of the airplane I would try and get more simulations done. I would suggest find someone who knows ANSYS and see if they will run it for you. I really like the design, and I want to see this do well. Just a word of warning.

Yepper yepper yepper. Main thing Alex keep it cheap. And I’ll buy a set

Alex, I respectfully request that you consider these questions. Did you consider the fact that the spring gear will flex in addition to the travel of the suspension system? Is it possible that the lower shock connection point could contact the ground which would put a torque on the gear leg and cause a sudden and severe tire misalignment? Do you have video of your spring gear in action which clearly shows how much it flexes under a hard landing condition? I recommend that you get a sense of how much the gear legs typically flex and how much your tires compress, then run a simulation with that taken into account. If the lowest point of the linkage comes within some uncomfortable distance to the ground (less than half the radius of the tire perhaps), then please rethink your design. I am concerned because the simulations that are shown in the video show a perfectly rigid gear leg and no tire flex. That is not reality. I know it is expensive, but perhaps a drop test that allows the tires to deflect out to the side is in order, similar to this: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-X384Z55XHT8.html What about water, sand and tall grass? Are you concerned about these factors? You designed your system such that each structure could withstand twice mgw. What is the margin of safety? What is the highest g loading your aircraft has experienced on landing? Is it possible that your aircraft will have to withstand a 4g landing? I enjoy watching your videos. Keep up the good work.

Wow. Excellent idea!! I love the analytical pragmatic engineering thinking. I wondering about the springy gear legs interaction. I see this might be a tremendous asset on Cessna taildraggers.

Very interesting. Ciao, Marco.

looks heavier and definitely not more aerodynamic - but it looks Cool!

I'm not a flyer but have watched a lot bush flying videos. The open cross shock system on the KitFox always gave me a bit of a cringe. Not only drag but ground clearance. With places these planes can land , all it would take is an unseen stick or poll or rock and rip those shocks right off. Well done

Awesome! Nice work

Great idea, Alex! The analysis you had done prior to fabrication should prove the design viable. Have you done any simulations with the change in track width both in straight and turning scenarios as well as opposite loading situations, i.e. 1 wing low . I would assume the parallel linkage would work better than the swing of the spring arm of the Grove gear. Will be looking forward to Part 2!

What are you landing on to require such a complex and heavy system. 7075 spring gear with aired down bush wheels should provide all the suspension you need. Want more ? Dump the heavy spring gear and go with conventional cabane struts with shock dampers. Keep it light!

I’m a aviation buff and my last name is Sessa as well crazy I didn’t know that they had more of us out there lol. Also used to be a mechanic love this video man I’m

Really cool

Alex that looks Incredible, and Lighter than i thought it would be. When you ran the actual weight I was amazed, with all the mounts and shocks 16# Total is superb... Do you have any idea what the weight difference (Total) is between a Grove with your design, and a set of Shock-Monster Cabane Gear??

Amazing!!

As an A&P with +15 years of commercial and general aviation maintenance experience, this is my honest opinion... Your taking a very simple and good landing gear system (not great but gets the job done) and basically making it more complex... This is awesome in terms of engineering and for better shock absorption but by making it more complex your also making it less user friendly in terms of maintenance. Hardware failure will be your enemy #1.

You could also put it on the zenith aircraft models!!!!!

How did this turn out? For me the kinematic has one disadvantage over the sweet package: low stroke on the dampers. Would be nice to hear about the results. Vid 3 yrs old I know. Thx.

I like it!

Might be interested in the design for an 801 I'm building. Might be paying you a visit to discuss design fees.

Top!

Whilst the coefficient of drag hasn't increased much, the frontal area has.

I'm having a hard time figuring out how this is supposed to work. Like, I get the parallel links keeping the camber as it compresses, etc. What I'm not understanding is a couple things. When you say "shocks" do you mean an oleo strut, some kind of shock-strut (spring and shock dampener), or just shock-absorbers like on a car, which are just dampeners? I'm also confused about how this system will interplay with the Grove gear. If the springs in the shock-gear are too stiff most of your forces will be taken up in the Grove gear legs. Please bear with me as I think this through aloud. If they're soft enough to keep the deflections within the new parallel link system, they may be too spongy to do much by themselves, once again putting the forces onto the original Grove gear... As the landing gear takes weight the Grove gear will deflect outwards, increasing camber and acting like the spring it is. This will try to extend your shock-absorber, but most of the force will be a side load on the shock mounting bolts. At the same time the parallel links will allow the gear to move up, also extending the shock, dampening that movement, but also reducing ground clearance. I worry that in hard landings the end of the parallel link the shock mounts to may have too much travel allowing the mechanism to contact an obstacle on the ground. Looking again at the animation of the gear at full travel there seems to be stops to prevent this. It's a very interesting engineering problem and I look forward to seeing how well your solution works. Subscribed.

What are you using for bearings in the pivots, paper-thin nolathane bushings and polished pins? old-school automotive style threaded bushes and threaded pins? polished pins in the parent metal? I appreciate your endeavour to minimise weight. My sense is the upper articulating link pairs and lower articulating link pairs need to be bridged together as single upper and lower control arms automotive style. Your pivot pins need to be entire across both link pairs not the short pins you have now which may deform along with their matching holes under bending and shear loads. I suspect that you may experience too much compliance in the links for brakes to work without severe, possibly destructive vibration caused by interaction with the compliance of the existing suspension. The links may wind up firm under momentary brake lockup, brake friction cracks free, links rebound, then brake friction grips and winds up the links again. It has been an issue for automotive engineers for many years and remains in modern coaches with control arm front suspensions supported by airbags. They require careful braking techniques by drivers when pulling to a halt or the rebound in the compliant suspension will make standing passengers uncomfortable. Even with pairs of links bridged together to stiffen your assembly, compliance and vibration may remain an issue which will worsen as parts wear. You are also introducing an extra unsprung mass between the runway surface and the airframe. As wear occurs, you may experience sudden transitions between toe-in and toe-out alignment independently in the main wheels as the tail raises or settles or one or the other tyre meets an obstruction like other wheeltracks in soft ground. It will not be a major movement but you do not need any in a tail wheeled aircraft. Please do not take notice of my comments directly but test them by asking a good engineer. I know only just enough to get myself into trouble. I wish you all the best in your endeavours and of course the joy of flying. I myself am a groundfowl. I have to content myself with watching.

Instead of a shock I would run an airbag because it gives you a lot more cushion but gives you the stability of a shock

Can you give us a video tour of your KitFox por favor?

what software did you use to simulate?

I wonder what the Cd is on the cabane gear is?

So the shock has an internal extension spring?

i am more of a cabana style kind of guy for performance over look, but i think you design is interesting and deserve tow thumb's up, every thing factored up , what is the weight of it, it think cabana is lighter and steadier with more travel but yo are right it's not as appealing to every buddy eyes .

this is awesome! Could something like this work for the gear on a C-170 or other similar airframe?

I was about to get the new gear that Trent Palmer has but will have to wait until you get yours tested. Keep me posted.. can you put something on your site so I can get in touch with your without being on utube.. Thanks Kitfox 6 owner w/o200.. Gene

Zenith Stol planes use the same type of gear. I am interested. I fly a Zenith 701

Is your kitfox shock gear available now and how much would it cost me?

what is the the shear of the pivot bolt ?????

How does the inevitable flex of the main aluminum spring factor into the travel or range of motion on the suspension system? Also, why have so much mass on the outside of the "knuckle" or the new mount position of the axle?

Brake lines? Itching to see your tidy solution!

at 5:08 this adds concentrated force at the point of attachment to the grove gear top side off shock? also the linkage system is pushing forces inward on grove gear at the axle axis. which is opposite of the normal design stress on the grove gear which goes outward.?

Very interested in your new gear. You've taken care of camber, but are there any adjustments for caster? I'm converting my Kitfox 7 to a tailgear and find I have to put some shim tabs on my Grove gear to get camber correct. Are you going to market this thru Kitfox or TK1??? Waiting on your test video. Thanks Rodney Wren

Alex keep me posted

WILGA GEAR HIDEOUS ? ...... Maybe on a Kitfox but on the Wilga DRACO they are AWESOME, just look at the flex or deflection when it lands ( absorbing the energy )..... LOVE some of the design ideas I see in your video, if you can make something work( light & simple ) I'm sure lots of us would like to see more..... how about those VG's you were going to install ?

Alex If its so over engineered for stress why didn't you reduce the mass to a more acceptable level ? After all weight is the "devil" on small planes...

What's the cost on a set? I've been fiddling with some designs for gear mods myself but I think your grove mod is a winner!! Well done, hopefully they will be available for purchase soon.

not much ground clearance under lower shock mounts