REFLECTOR: Retractable Gear Issue--- long story

[Jack Prock via Reflector]

Hi,

 

I just wanted to follow up with what I found and how I fixed it. So others may not need to go through this stress.

 

Scott B. and several others had suggested that it was probably the gear going into the gear sockets that seemed to be the culprit. So I disconnected the locking arm, then wrapped the gear in sand paper and moved each gear through the socket a few hundred times. Both sockets seemed too rough and quite tight. I had rubbing on each leg when it entered the socket. On the ground this friction didn’t seem to be of any consequence, but once in the air with the air loads, the gear flexed just enough to put more pressure between the socket and the forward gear face. I also sanded off the micro I had on the front part of each leg where it touched the socket. I then coated both front legs and the gear socket with lithium grease.

 

I then exercised the legs as two guys pulled on ropes attached to the bottom of the gear. 

 

All went smoothly, so I went flying this morning and raised the gear. As Scott B. suggested, I carried a big stick just in case I got stuck in the same situation. 

 

Everything worked great. Went up and down just like it was supposed to.

 

I was very lucky, this whole thing could have turned out much differently. 

 

Jack

 

From: Reflector [mailto:reflector-bounces at tvbf.org] On Behalf Of Jack Prock via Reflector
Sent: Sunday, September 28, 2014 11:27 AM
To: 'Velocity Aircraft Owners and Builders list'
Subject: REFLECTOR: Retractable Gear Issue--- long story

 

HI,

 

So I have been doing test flying of my new XL-RG and I was having an issue with the oil not cooling. Turned out the Vernatherm was not closing completely. Made every flight under 15 minutes, which was frustrating. Anyway, this morning I went out to test my latest change to see if the oil temp would stabilize. So within 15 minutes it was steady at 220… YEA! It was nice to not be able to fly and not worry about that.

 

So after 20 minutes, oil temp steady, I decided to raise the landing gear. Mind you, I had raised and lowered the gear probably 40 or 50 times over the past 8 years, and every time they came up and went down perfectly. I had also made sure that the wheel wells had clearance, since a friend had that issue in his Velo. So they came up great, I was sitting fat, dumb and happy. I then went to lower them and they lowered fine… or so I thought. I looked down and I had two yellow lights on the rear gear. I looked back and they had lowered 90%, but the over center arms had not locked. They were about 2 inches above locking. 

 

I cycled them a half dozen more times, and every time the rear gear would stop at the same point. I don’t have the rear cover panel on, so I can easily see the gear arms. Man it was so frustrating to be sitting there, be able to see them, and not crawl back there to push them down the last two inches. 

 

So I flew around for a while and tried yanking on the yoke a bit to see if I could get them to budge. Mind you I have about a total of 1 hour on the plane at this point, so I am still being very cautious about any sudden movements of the control surfaces. 

 

Long story short I declared an emergency, and told somebody on the ground to let 911 know there may be an issue with the gear. He got them on the line but they didn’t send anyone out, since to the guy on the ground it looked like the gear was down.

 

Lincoln Ca is 6000+ feet long, so I had time to touch the gear on the ground and try and get them to lock. And luckily, that is what happened. I touched the left main, raised the plane up a few feet, and I heard the gear lock. A quick look at the indicator lights and I had 3 green. Landed uneventfully and felt very lucky this didn’t turn into a very expensive flight.

 

So now the question to the group. Does anyone grease the landing gear bolts? Something is binding. Anyone have any experience with this? There are 5 total joints in the rear gear landing mechanism and one of them is binding when there is a rearward force being applied. 

 

I think the best way to test this moving forward is to lower the gear with two people pulling ropes attached to the gear so that I can make sure the gear isn’t binding with a rearward force. 

 

Anyone have any experience, guidance, snide comments?

 

Jack

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