Nose gear spring replacement

This entry is part 37 of 39 in the series 07 - Landing Gear

Bouncing along on a amusement park ride.

That’s what one of my landings felt like. But it wasn’t my fault!  Runway 05/23 at Sebastian is not a very smooth runway.  Lots of dips.  On the above referenced landing, I hit one of these dips and got catapulted into the ceiling.  Now even with my seat and rail system modified, I don’t have much headroom… so at least I didn’t develop much momentum.

I think it was the day after that landing I was rolling up to the builders service center and Scott was watching me taxi up.  He had a very concerned look on his face.  Which was causing me to get a very concerned look on mine.

I shut down and got out and said “What?!?!”. He said “Something’s not right with your nose gear strut.”  Then he walked over and with one hand pushed down on the nose. When he did, the nose when down and the nose wheel sprung forward.  Then he said “This spring is too weak.  I shouldn’t be able to compress the spring at all.”

Normally, it would take a putting the weight of your whole body on the nose to begin to compress the spring.

At some point in the past, Velocity had some weak-ass springs. Scott asked what color my nose gear spring was. I told I wasn’t sure but I would check tonight. He said it felt like one of the white ones.  So I put the airplane away for the night and once back at the hotel, I looked through my pictures.

From January 25, 2008…

2008-01-25 1026 IMG_5873


The next morning, I taxied over to the Builders Service Center.  Scott was waiting.  “Well?” he asked.  I just shook my head.  He was visibly unhappy. “I thought that we found everybody that had a white spring and replaced them.”

He said the biggest danger is that when the spring compresses enough, the top of the gear is not supported against side loads.

Here’s a diagram that shows the nose gear assembly from the left side.

Nose Gear

This is showing the “Down and Locked” position. At the bottom of the nose gear is the wheel (out of the diagram, bottom left). At the top is the spring (in red). The blue “captivator” is a U-shaped steel bracket which prevents the top of the assembly from moving left to right. When weight is put on the nose of the plane, the spring compresses, the wheel moves up (and forward) and the top of the assembly moves back. If it’s just a little, it’s not a problem. If the top moves back enough, the top is no longer in the captivator.

The big problem with my weak-ass spring is that with just my weight in the pilot seat, the spring was already compressed some. Any bump (or another person in the front seat) and the spring is compressed enough so the top of the gear assembly is now out of the captivator. Which means a nose gear collapse is just a matter of time.

Scott then asked about my takeoffs. I told him the plane stays firmly on the ground until I pull up. He nodded and said “Yep. That’s what I figured.”  With the pitch trim set for takeoff but the spring compressed, the canard was not at the normal angle of attack. So it’s not creating any lift.  But once I pulled back on the stick just enough, the spring would uncompress, and the canard would then generate lift and the plane leaps off the ground.

So now what?

Scott said it’s not too bad of a job to pull the shock out.  So I started by removing the canard. Then it’s just the two bolts at either end of the shock.  It took me about an hour.

Then we rode over to the machine shop where Scott had already pulled a new (red) spring. With a special fixture for the press, the old spring was removed and the new one installed in about 3 minutes. Without a press, that would have taken me a whole day to figure out how to do that.

Another hour to put everything back together and Charlie Mike was ready to go. Total time, about 2.5 hours. That right there made the numerous trips back and forth between Panama City and Sebastian worth it.  If I hadn’t been there, Scott wouldn’t have noticed it. And I wouldn’t have since I didn’t have enough Velocity time to know that is was too soft.

The next takeoff was so much nicer. The plane literally flew off the runway. And the landing was so much better as well.

Series Navigation<< 11.1.4 Lower Cowling to Wing Flanges7.2 – Nose Gear Door Actuator Replacement >>