Ragwing fuel line reroute

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gobrien
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Ragwing fuel line reroute

Post by gobrien »

I have read the various posts about 48 rag wing fuel pump replacement, necessity, mechanical versus electrical and finally removal and replacement with rerouted fuel lines. My preference is to route the fuel lines down the b posts at the back of the doors in the manner of the 170 A, B and subsequent 172s and delete the check valve and fuel pump.

Questions:
1. Does anybody have a 337 for a 48 rag wing with this done?
2. Is it possible to do this without removing the floor and the seat rails? Cos I really really would rather not! 8O

Thanks

Gareth
1948 170 Project (N4180V) now EI-AEN SN:18513 - Dublin, Ireland
https://www.taildragger.eu/
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n2582d
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Re: Ragwing fuel line reroute

Post by n2582d »

Gareth,
You'd have to be Houdini to install those lines without removing the floor. I'm not too familiar with the '48 but wouldn't the cabin heat ducting be in the way? If the goal is to get rid of the mechanical pump there is field approval 076-2 filed here for replacing the mechanical pump with an electrical one.
Gary
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GAHorn
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Re: Ragwing fuel line reroute

Post by GAHorn »

The problem with field approvals is that FAA no longer automatically accepts them as approval for new installations without engineering support.

I do not believe the fuel line size is any different between the ragwing and later models (all being AN6 if I recall correctly...don’t have my IPC available just now to reaffirm that)...but it is the routing that makes the fuel flow at high power/high AOA that restricts the ragwing because the certification-required fuel flow falls off in a gravity system routed such as the ragwing has.
I do think the re-route could be easier to obtain approval than the change to an electric pump by reference to later design by Cessna. My opinion only. Before undertaking either venture check with your FSDO.

The problem for a ragwing in a re-route might be more an issue of which fuel selector valve location is in the particular serial number airframe more than the heater ducts I would think.

If it were me, I’d simply install/add the pump and check valve and get on down the road with an original design.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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gobrien
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Re: Ragwing fuel line reroute

Post by gobrien »

n2582d wrote:Gareth,
You'd have to be Houdini to install those lines without removing the floor. I'm not too familiar with the '48 but wouldn't the cabin heat ducting be in the way? If the goal is to get rid of the mechanical pump there is field approval 076-2 filed here for replacing the mechanical pump with an electrical one.
I went throught the STCs and 337s today and N4180V had an electrical fuel pump installed previously on a 337. According to the last owner it was removed before they bought it; the placard and switch are gone. I'm told there was no mechanical pump was on the last engine (I don't have that engine) in which case she was illegal. Either way my replacement engine (O-300-B from a 172) has no mechanical pump. Best price I can find on the Tempest 40585 rebuilt FUEL PUMP 3.5 - 4.5 PSI is over $1000 including core whereas the Facet pump from the 337 Gary references above is a whole GBP80 brand new with a 60 year track record. I'm redoing the whole electrical system anyway so adding the electrical pump is no big deal to add. Keep in mind I don't need a new 337 signed off; this is a technical enquiry rather than regulatory:

Questions:
1. Can anyone suggest a reason why the electrical pump might have been pulled?

2. Has anyone currently got a 48 flying with an electrical pump rather than the mechanical one?

3. Given the reason for the mechanical pump is the forward routing of the fuel lines in the 48 model (which I'm trying to avoid rerouting) can anyone see why the electric boost pump for TO and landing wouldn't solve the problem nicely?

Thanks!
1948 170 Project (N4180V) now EI-AEN SN:18513 - Dublin, Ireland
https://www.taildragger.eu/
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Bruce Fenstermacher
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Re: Ragwing fuel line reroute

Post by Bruce Fenstermacher »

Member Duane Shockey has a '48 legally flying with an electric fuel pump . Duane does not frequent the forums.
CAUTION - My forum posts may be worth what you paid for them!

Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
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gobrien
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Re: Ragwing fuel line reroute

Post by gobrien »

Perfect. Thanks Bruce!
1948 170 Project (N4180V) now EI-AEN SN:18513 - Dublin, Ireland
https://www.taildragger.eu/
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GAHorn
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Re: Ragwing fuel line reroute

Post by GAHorn »

For reasons Duane can remunerate IIRC, his is the only airplane which is approved for an electric pump and it’s only applicable to his. As this is a technical question (and not a legal one) ... Duane is doubtless the guy with which to visit.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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