Warning for "A" gear models

terrykohler · #1 05-21-2007, 06:14 AM

I'm currently conducting a condition inspection on my 9A and noticed a broken exhaust hanger on one side (one of the flattened end tubes that fit into the rubber hose had fractured at the crimp). The broken hanger had allowed the exhaust to move a bit more laterally and had begun contacting the nose gear brace. Wear on the gear structure was noticable and would have resulted in fracture if left unchecked.
My friendly AI advised against my plan to pin the exhaust stacks into position and told me that 1/2 inch movement should be allowed in each direction. The fix was to move the stacks outboard as much as my cowl would allow and then cover the six inch section of gear tube with 3/4in. I.D. heater hose which had been split and fixed with hose clamps.
This wear on the gear structure was also discovered on another "A" on RV Row at KPTK. In this case, no broken hanger, but pipes mounted too close together. INSPECT YOUR NOSE GEAR SUPPORT STRUCTURE. CHECK YOUR PIPE CLEARANCE.
Terry
RV9A
N323TP

godspeed · #2 05-21-2007, 07:58 AM

I would love to see pictures , so I can be preventive before it happens..

Danny..

khm · #3 05-21-2007, 08:34 AM

Terry,

If your plane may still be apart Saturday I would like to stop by and see it.

Keith

Jeff Vaughan · #4 05-21-2007, 09:56 AM

Where does one find 3/4" ID heater hose?

Vern · #5 05-21-2007, 12:23 PM

It's a common item at an auto parts store. I mounted the screw side of a hose clamp towards my exhaust on my 6a when I noticed some chaffing from exhaust vibration.

terrykohler · #6 05-21-2007, 12:32 PM

Danny: No pictures available, but if you look at your engine mount/gear tower you'll see that the pipes may be capable of contacting one of the lower tubes that supports the nose gear socket. These tubes are 3/4 in dia. and connect the lower firewall frame to the socket. General direction is fore/aft. The damage surprised me in that the exhaust pipe was hammering a flat spot about 3/4 in long onto this tube. Of course, paint was worn off.

Keith: Cowl is back on, but the split hoses I have added to the structure are visible by looking into the cowl outlet. Hangar will be open from 0845 to 0930 if you want to take a look. You can also see 3-4 other RVs at that time if you wish. Call beforehand, I'll need to use my pass to get you thru security. My cell is 248-417-8585.

Jeff: What Vern said. You'll need 12 inches if you're going to cover both sides.

Terry
RV9A
N323TP