Locally the Feds require a gascolator be installed in the low point of the fuel system. This is not quite possible on an RV as the wing tank drains are the low point, but it was either follow the regs or don't fly.
I chose an Andair gascolator. All was fine for about 200 hours. The DV125 drain valve started to produce a blue stain on the tip of the drain for a few months. Then one post flight I found a blue streak on the belly about a foot long. This was in close proximity to the exhaust exits. Flushing did not cure the issue, so I gave up and replaced the valve.
However on my next take off I discovered considerably more take off thrust.
Almost like adding afterburner thrust.
Evidently the leak had been allowing air to enter the fuel system at take off power and reducing power.
I have disassembled the old drain valve and found the O-ring to be in poor condition and need of replacement.
Perhaps heat and or vibration from the exhaust stacks contributed to the degradation of the O-ring. I think that this area(between your feet) of an RV-4 or Rocket is a less than ideal location for a gascolator.
I'll be looking for a safer solution in the long term. In the short term,a #006 Oring has too thick a cross section. Only the 1/8" ID is the same. the #6 is the smallest available locally.
The one that was in the valve is .125" ID x.206" OD x .037" cross section dia.
Does anybody know the proper # designation to buy these Viton O-rings for the Andair DV125?
I sent Andair an e-mail.
I chose an Andair gascolator. All was fine for about 200 hours. The DV125 drain valve started to produce a blue stain on the tip of the drain for a few months. Then one post flight I found a blue streak on the belly about a foot long. This was in close proximity to the exhaust exits. Flushing did not cure the issue, so I gave up and replaced the valve.
However on my next take off I discovered considerably more take off thrust.
Almost like adding afterburner thrust.
Evidently the leak had been allowing air to enter the fuel system at take off power and reducing power.
I have disassembled the old drain valve and found the O-ring to be in poor condition and need of replacement.
Perhaps heat and or vibration from the exhaust stacks contributed to the degradation of the O-ring. I think that this area(between your feet) of an RV-4 or Rocket is a less than ideal location for a gascolator.
I'll be looking for a safer solution in the long term. In the short term,a #006 Oring has too thick a cross section. Only the 1/8" ID is the same. the #6 is the smallest available locally.
The one that was in the valve is .125" ID x.206" OD x .037" cross section dia.
Does anybody know the proper # designation to buy these Viton O-rings for the Andair DV125?
I sent Andair an e-mail.
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