Posted 4 Apr 2022 I'm just getting into building my " longer, wider " gear for my modded KF1 project and noticed on Youtube there is a couple of fellas down South who have not only a cabane style bungee shock system but that is actually supplemented by a secondary shock cord system. It appears to be just a wire from one inboard axle fitting over to the other inboard axle system with enough slack in it wire to allow two extra " floating " shock "straps" to get attached up to the aft landing gear leg / fuselage fitting on each side. The theory is that the main shocks can be set up looser for smooth ops in normal landings but if the going gets tough, the upper supplementary shocks come into play to assist. Kinda hard to explain, but if you search Youtube for Kitfox Tweety Bird you'll see the system in operation. If this is a good idea, where would one find a " flat strap " type of bungee for the upper part pulling on the wire ? Any thoughts appreciated... Share this post Link to post Share on other sites
Posted 5 Apr 2022 never seen that. looks pretty cool. thanks for the link! Share this post Link to post Share on other sites
Posted 4 May 2022 I'm getting further along on the new landing gear and have built both sides and the cabane and now just getting into the shock struts. Fuselage height will be about 31" off the ground with the 20" tires and center to center "track" of the tires will be about 76" sitting with wheels vertical. The fuselage is upside down on the floor of my garage for all this fitting. Now the bungee situation is getting very interesting....at least to me. I referenced the "Tweety bird" vid on youtube above and took many notes/ideas from that. I bought a 30' piece of 3/8" "marine grade" bungee for testing. My bungee attach points on the shock strut are about 12" apart from another with the gear " up tight " ....or collapsed inward as if in the air flying. I made a single bungee with a short loop on one end to fit the shock strut attach point and made another short loop about 30" away. Hook the one loop on one end, go around the other end, wrap around the first end and attach the bungee loop to the second end. For sake of simplicity, we have 3 lengths in play now. I then put a second, similar bungee on the other side of the shock strut with the same three lengths and gave it the pull test. Seems interesting and progressing nicely. Then I took one bungee off one side and pulled it on harder and got it hooked up with four lengths. Harder to pull but felt smooth and predictable. Took the other bungee off and and pulled it up to four lengths too and couldn't budge the bugger. It then dawned on me that we have almost endless possibilities here with tuning the suspension any way I like / need it. I could even introduce any number of bungees of slightly different lengths to get some " progressive" resistance in the tuning of the gear. I know all will be different on the field ready to fly but it seems to show that I will be able to conduct more serious tests in the garage with the wheels on and enough weight loaded onto the fuselage to approximate a fully loaded airplane in the hangar. Any thoughts ? Dave. Share this post Link to post Share on other sites
Posted 4 May 2022 I would like to see some pictures. I'm thinking of building a gear for my new Kitfox 4 project. JImChuk Share this post Link to post Share on other sites
Posted 4 May 2022 Well i dont know it all, havent seen it all, but,,,,, thats about one of the dumbest setups ive seen, y do u need extra bungies on the back hooked to a cable, and deadmaned to ur axels, when u have the regular bush gear setup, seems to me ur addin junk, and dont have ur main gear setupmright for ur airpplane or ur type of flyin there a video of him flyin around so u get a good look. That just seams like a not needed idea Share this post Link to post Share on other sites
Posted 5 May 2022 To be clear, Buckchop...I referenced the Tweety bird setup because it seemed innovative and seems to work for that guy. Who knows what "really" works for stuff you see or hear on the internet I guess. You do seem to be well informed on landing gear setups. Could you please offer an opinion on my approach which is outlined above ? Thanks, Dave 1 person likes this Share this post Link to post Share on other sites
Posted 6 May 2022 Yes i know ur refering to the Tweety Bird, i like the plane, but not the gear, gave my opinion on it, just seems like more stuff thats not needed, we been runnin the cabane vee gear since piper started and it works, most everyone copies it in some form or another, so y add more bungies to do the same job. A good buddy told me to KISS those airplane builds. Keep It Simple Stupid. Share this post Link to post Share on other sites
Posted 7 May 2022 Yep, I agree. KISS is good. Just looking for open opinions / ideas. I think my arrangement will be just fine with a variety of bungee combinations that could be installed. I will add separate tangs from the front and rear gear attach points for skis anyway. I built a Christavia with springs and my current Headwind has springs too. I got the calculation right and they work fine. The trouble with springs is that they are non adjustable while with bungees, the possibilities for adjustment are just about endless. I'll put up some pics when they are finished and in primer. Man....Aircraft Spruce is really short on tubing selection right now. Share this post Link to post Share on other sites
Posted 7 May 2022 Springs r adjustable, they make different rate springs and then u can shim the spring to fine tune it. Share this post Link to post Share on other sites
Posted 18 May 2022 Springs R not adjustable....you have to buy different springs if the ones you buy don't work right. Yes, you can shim springs if they are not strong enough but then you loose compressible length. Not trying to argue here....I just think bungees add more opportunity to tweak . We'll see. Share this post Link to post Share on other sites
Posted 19 May 2022 Yes thats y u go thro all the spring on the spring chart, have a startin point and when i say shim the spring im NOT talkin a 1/4 inch, only the thickness of a washer in that diameter. Im not going argue we both have good points, but i know what i did to get my gear to work right and it works right for my use, and im not easy on it by no means and others have done the same to thier gear also, hell i just copied the springs and rate that others did on thier gear on this same site. Leni has all the info that started the skidoo spring mod Share this post Link to post Share on other sites
