Gear doors slow to close

hew · #1 11-02-12, 05:31 PM

This does not happen on jacks with the test rig. It also does not happen on gear extension. It happen during climb, usually full power, haven't tried reduced power. Suggests to me three possibilities. 1. Not enough pressure from the pumps but I have two of them. 2. Something in the power pack. 3. The snubbing valve on the main gear actuator needs adjusting.
If anyone else has had a similar problem we might know where to start looking.

hew · #2 11-02-12, 05:49 PM

BTW, in the parts catalog the snubber valve is called a metering pin, #17 on figure 160 p/n 294604-1. Don't want to mess with this if it's not known to cause a problem.

hharney · #3 11-04-12, 12:20 PM

When you test it on jacks on the ground, what is the source of energy? Are you using the engine pumps or a mule? It is very easy to use the engine pumps on the aircraft to test the system. See my video

http://www.youtube.com/watch?v=w67UYBa48Lg&feature=plcp

hew · #4 11-04-12, 08:58 PM

Thanks Herb, yes we used a power pack which may have had a better pressure than the engine pumps. I love your electric drill adaptor to turn the engine pump. Saves a whole lot of hassle. Did you have a pressure gauge on the pump outlet side to see what was going on? What size drill (watts)?
I am leaning toward the hydraulic filters partly blocked or the solenoid sticking or intermittent electrical fault on the up lock switches / up-down switch. We've had a few other problems where soldered connections are broken but held together just enough by the heat shrink insulation.

hew · #5 11-05-12, 10:34 PM

Herb, the video raised a couple of questions.
1. did you have a torque arm bolted to the pump to stop it spinning on the end of the drill?
2. The vortex generators in front of the wheel wells, do these come with the kit & do they help?

hharney · #6 11-06-12, 11:16 AM

I am not following your question about the torque arm spinning on the end of the drill. The pump is removed and the drill provides the energy to run the pump. Just hold it in hand to operate

The VG's are part of the Horton STOL kit. Not sure on the effectiveness but must provide some benefit in stability at slow speed. Originally from the R-STOL system and copied by Horton

hew · #7 11-06-12, 07:40 PM

OK, I guess the hoses and a strong hand prevents the pump spinning on the end of the drill. I'll try it and see.