Check Valve PN 475-GG-1/4D
Posted: Tue Feb 17, 2009 9:50 pm
Be advised that this check valve (required only on C-170 ragwing aircraft) PN: 475-GG-1/4D has been superceded to PN:453/1/4/26 (this may be a typographical error due to computer-speak and may actually be PN:453-1/4-26 )
Recent inquiries have been rec'd by me regarding this check valve, which is used in conjunction with an engine-driven fuel pump on the original fabric-wing fuel system. That system's fuel-line routing may contribute to low fuel-pressure without the mandatory pump and check valve. During takeoff and climb insufficient fuel pressure exists due to fuel line routing down the forward door posts of the fabric-winged aircraft. (Metal wing A/B models routed the fuel line down the aft door post.) The purpose of the check valve is to prevent the fuel pump from back-feeding itself with pressure, while allowing gravity-flow to continue supplying fuel to the carburetor in the event of pump failure.
Member Duane Shockey is attempting to assist ragwing owners obtain a replacement source for these check valves. Any owner of a ragwing 170 should confirm the presence of their pumps and check valves. Anyone needing a pump can obtain them from Aircraft Spruce and other suppliers. Anyone needing a check valve should contact either Duane Shockey or myself to add their request to the manufacturing-order.
PS: Just for everyone's enjoyment: I rec'd a phone call yesterday which started out just like many other phone calls from fellow members looking for assistance on their airplane. It went like this:
Rrriinnnng: Hello.
Caller: Hello, I'm looking to speak to George Horn.
Me: Speaking, how can I help you?
Caller: We've got a customer with a Cessna 170 in for service and his airplane doesn't have a check valve which is called for in the parts catalog. Can you help us?
Me: Is the customer a Int'l Cessna 170 Assn member?
Caller: No, but I found you thru the 170 dot-org website.
Me: That's fine, I always help all callers, I just like to know which Member airplane I might be discussing. I take it that the airplane in question is a 1948 ragwing?
Caller: Yes, and we can't seem to locate any references or sources for that check valve PN: 475-GG-1/4D. Do you have one or know where we can obtain one?
Me: That's another reason I asked if your customer is one of our Members, because we're presently attempting to put a manufacturing-order together with the original mfr'r.
Caller: Oh! So you KNOW who the OEM is? .... and have a contact?...
Me: Yes, but we need to place an order for at least ten before we can obtain them at an affordable price, and I wanted to make certain that we weren't duplicating efforts for one of our own Members.
Caller: OK, I see. Well, we've tried everything we can to find information on the original vendor and we simply didn't keep that information and was hoping you might be able to help us since you are the resource our single-engine propulsion folks recommend for information.
Me: (after a pause trying to figure out all that terminology/buzz-words): And exactly WHO are you representing?
Caller: Oh, I'm sorry. I should have told you. I am John Doe, fuel-systems support engineer, single-engine populsion unit, Cessna Aircraft .
Me: (pause) You mean you represent the Cessna factory in Wichita?
Caller: Yes. ... ... ...
===================================
I thought you guys might enjoy that. This is now the third time in the last couple of years that someone from Cessna has called us directly seeking information on their own design. BTW, the fellow that called is with the design engineering team on the new Skycatcher. We had an interesting discussion following this one. He's a very nice fellow (his real name not used above) and it seems that a great deal of original engineering data was not kept by Cessna from the late 1940's. He offered to buy several check valves if we got anywhere near to filling our order, so you guys who need check valves better speak up while the opportuity exists.
Recent inquiries have been rec'd by me regarding this check valve, which is used in conjunction with an engine-driven fuel pump on the original fabric-wing fuel system. That system's fuel-line routing may contribute to low fuel-pressure without the mandatory pump and check valve. During takeoff and climb insufficient fuel pressure exists due to fuel line routing down the forward door posts of the fabric-winged aircraft. (Metal wing A/B models routed the fuel line down the aft door post.) The purpose of the check valve is to prevent the fuel pump from back-feeding itself with pressure, while allowing gravity-flow to continue supplying fuel to the carburetor in the event of pump failure.
Member Duane Shockey is attempting to assist ragwing owners obtain a replacement source for these check valves. Any owner of a ragwing 170 should confirm the presence of their pumps and check valves. Anyone needing a pump can obtain them from Aircraft Spruce and other suppliers. Anyone needing a check valve should contact either Duane Shockey or myself to add their request to the manufacturing-order.
- 170 fuel system schematic.JPG (16.96 KiB) Viewed 4198 times
Rrriinnnng: Hello.
Caller: Hello, I'm looking to speak to George Horn.
Me: Speaking, how can I help you?
Caller: We've got a customer with a Cessna 170 in for service and his airplane doesn't have a check valve which is called for in the parts catalog. Can you help us?
Me: Is the customer a Int'l Cessna 170 Assn member?
Caller: No, but I found you thru the 170 dot-org website.
Me: That's fine, I always help all callers, I just like to know which Member airplane I might be discussing. I take it that the airplane in question is a 1948 ragwing?
Caller: Yes, and we can't seem to locate any references or sources for that check valve PN: 475-GG-1/4D. Do you have one or know where we can obtain one?
Me: That's another reason I asked if your customer is one of our Members, because we're presently attempting to put a manufacturing-order together with the original mfr'r.
Caller: Oh! So you KNOW who the OEM is? .... and have a contact?...
Me: Yes, but we need to place an order for at least ten before we can obtain them at an affordable price, and I wanted to make certain that we weren't duplicating efforts for one of our own Members.
Caller: OK, I see. Well, we've tried everything we can to find information on the original vendor and we simply didn't keep that information and was hoping you might be able to help us since you are the resource our single-engine propulsion folks recommend for information.
Me: (after a pause trying to figure out all that terminology/buzz-words): And exactly WHO are you representing?
Caller: Oh, I'm sorry. I should have told you. I am John Doe, fuel-systems support engineer, single-engine populsion unit, Cessna Aircraft .
Me: (pause) You mean you represent the Cessna factory in Wichita?
Caller: Yes. ... ... ...
===================================
I thought you guys might enjoy that. This is now the third time in the last couple of years that someone from Cessna has called us directly seeking information on their own design. BTW, the fellow that called is with the design engineering team on the new Skycatcher. We had an interesting discussion following this one. He's a very nice fellow (his real name not used above) and it seems that a great deal of original engineering data was not kept by Cessna from the late 1940's. He offered to buy several check valves if we got anywhere near to filling our order, so you guys who need check valves better speak up while the opportuity exists.
