SonexBuilders.net

Anyone notice or have the issue where past 120knots there's a very pronounced flutter in the nose? It feels like a out of balance tire. I can see the aluminum on the floorboard moving and I know it's not the engine. (New mount, engine, and bushings 10 hours ago due to improper installation and running too lean)

I've heard the fin on the fairing can flutter and the tire is also known to start spinning in the prop wash. At cruise the plane hauls.. but I can't stand the whole thing shaking.

Hi brendan,
Try flying with the nose pant off. See if that helps. If not try balancing with glass beads in the nose tire.
Any others with tri gear have ideas? Let us know how your testing goes....


WaiexN143NM
Michael.

I discovered my nose wheel spins pretty good while cruising. If it's a balance problem, you might try swapping the nose wheel with a main - if they are the same size.
Bob Sonex 550 trigear Jab 2200.

You call it flutter and if it truly is flutter it's very serious. Your nose wheel steering should be spring loaded like my Onex. I highly doubt that the nose wheel pant would flutter unless there is a lot of play in the steering. I have seen 160 mph on mine with no vibration. Tires spinning fast enough to be out of balance? Doesn't happen. Flutter is a serious problem and if it's a control surface it can be fatal. Zenith had four or five fatalities attributed to unbalanced ailerons and they made a major engineering change to prevent it. Flutter should not happen on a Sonex.

Maybe mount a GoPro in such a fashion. To have some eyes on the situation

I have observed the nose wheel spinning pretty fast when flying formation with a Grumman Tiger leading, with a nose wheel pant on. When replacing tires, I plan to avoid tires with any cross wise tread for this reason. This is surprising because when I remove wheels, repack the bearings and reinstall, there is a little friction for the wheel turning. I go to the tighter, versus looser, setting to get a cotter pin through the castellated wheel nut.

Onex107 wrote:You call it flutter and if it truly is flutter it's very serious. Your nose wheel steering should be spring loaded like my Onex. I highly doubt that the nose wheel pant would flutter unless there is a lot of play in the steering. I have seen 160 mph on mine with no vibration. Tires spinning fast enough to be out of balance? Doesn't happen. Flutter is a serious problem and if it's a control surface it can be fatal. Zenith had four or five fatalities attributed to unbalanced ailerons and they made a major engineering change to prevent it. Flutter should not happen on a Sonex.

Its not flutter per se, its just vibration. I know its not the airframe. it feels exactly like a out of balance tire. I noticed recently that on takeoff i feel the same vibration and it slows down. if i hit the brakes it doesnt go away meaning its the nose wheel. I think ill try to balance the wheel and see if it helps.

Had the same issue on my Glastar. Puzzled me for a long time. Finally figured out the problem was the nose wheel axle nuts were too lose. At speed the nose wheel would start turning (with or without the wheel pant) and not being in good balance it would shake the whole dang airframe, even the main wheels. Tightening the axle nuts mire fixed that. :)

We finally got it figured out.

Noticed if I did a high speed pass down the runway with a crosswind the shake went away if I crabbed to the right. I landed and took a look, and noticed the nose gear was turning left when the rudder was centered. I had a friend eyeball the nose gear and fairing, while I adjusted the end link on the rudder pedal so the nose gear was in trail with the rudder. That fixed the issue and it's been smooth since!

I would always experience a shutter/vibration during climb out as the front wheel slowed down. I also experienced an intermittent vibration after hitting a groove or bump in the taxiway/runway. It literally felt like the airplane was going to shake apart. I swapped wheels and tires, new wheel pants, bearings, new tires and nothing seemed to fix the issue. I also had the issue of the front wheel spinning in flight but didnt really notice a vibration from it. Decided to convert from the trigear to a tailwheel over the winter. first flight coming soon. Im running a jabiru 3300. Good Luck I just gave up on finding a solution plus needed to put my new tailwheel endorsement to use.