Hello everybody! Glad to find this forum. I've got a tri gear Hummelbird that was built by someone else out in Ohio. It came to me via Enid Oklahoma a couple of years ago. I'm in Minnesota. Anyway, the original builder made a fully castering nose wheel assembly, no connection to the rudder pedals at all. The castering nose wheel would get into a wobble from time to time, just like a castering grocery store cart wheel. The 4th time i flew the plane the metal that the nose wheel yoke was made of broke right next to the weld that attached the yoke to the front strut and the nose wheel flopped over on its side. Bad luck i guess, and bad judgement on my part for flying the plane knowing it had this problem. Anyway, i've converted it back to the original plans configuration where the nose strut is linked to the rudder pedals with several bits, including two springs referred to in the plans as 'cot springs', and that's what this post is about. If anyone has any familiarity with this set up i'd sure like to know what you used as 'cot springs'. I've tried three different sets of springs and am not at all sure i've got a suitable set of springs in there right now as i'm waiting for the weather to clear off enough to taxi test it. Tried to get the hangar door open yesterday, an actual above freezing day, but no luck, the door was frozen to the floor at the bottom edge seal. Any advice or info appreciated. Thanks! Bruce
Hi, I don't have a Hummel (yet) just a set of plans. But I do live in MN, Mpls area. Where are you located? Thanks, Mark
Hello Mark,
I'm in North Branch, about 50 miles straight up I35 from down town Minneapolis. My HB is at Rush City (KROS) maybe another 12 miles north. BTW I taxi tested the nose wheel steering springs mentioned in the original post, they work great! I have the Grainger part number of the springs if you need it for your build. Bruce
Bruce,
If the geometry is right, the castering nose wheel can work great. That said, You are very wise to change it on the HB. As for the springs, I am sure when Morry was doing the plans for the HB there was a cot in the corner of his shop that he took 2 springs from for his nose gear. I will apologize for not fixing that on the plans in the last 18 years. Hopefully Matt and Laurie will find time to update the HB plans. My recommendation would be to eliminate the springs altogether and connect the nose wheel directly to the rudder pedal with rods and a belcrank same as the H5. We also learned with the UC and H5 that 7-10 degrees positive rake on the nose strut is about right.
Good morning Terry, good to hear from you!
I actually thought about running a direct link instead of the springs but then immediately remembered how fragile nose struts can be so I'm sticking with the springs for now. The problem (in my real life influenced imagination) is that if you damage the nose strut and can no longer make the nose strut turn, you also lose rudder control with the direct link setup. With the spring linkage you still have rudder control even with a locked up nose strut. I'm hoping to test fly my 'back to plans' nose wheel set up within a couple of weeks. I'll post the spring numbers here if they work as well flying as they do taxi'ing around between the hangars. Bruce