Fueling system replacement, what would you do?

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rsrguy3

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Around a month ago we bought a pzl frank 220hp powered 801..

An Interesting issue reared it's head on the condition inspection I'm working towards completing on the 801. My IA pointed out my fuel supply lines may be a bit too small (3/8) ID. Neither he or I were comfortable with the rubber auto fuel lines used to connect the tanks to the solid lines in the fuse. That is what prompted the question, "are these lines to small for the application?" .

Further research indicates other a/c's with this PP utilize 1/2" lines and the 43.13 suggests the lines it was built with are too small.

I understand that ex aircraft are not necessarily held to the 43.13, but this looks like a solid benchmark to aim for. I looks like a complete retrofit is in order...

Speed seal was suggested as a good option, it looks like a good one, what do you experienced builders think?
 

TFF

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With that much power, 3/8” is probably marginal. AC43 is always good to follow unless you want to experiment.
 

rsrguy3

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I don't want to experiment, I'm certain .5" is the way to go. I'm surprised the two ia's and Der before our ownership didn't catch this.
 

wsimpso1

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I gotta ask: How has it been flying? Does it make good power on take-off and in climb? Does it give any hints that it is starving for fuel at high power?

If it flies now without fuel starvation, wouldn't this be fixing something that ain't broke?

Alternatively, if it is short on power during take-off and/or climb, maybe you retrofit with 1/2" tube.

I do agree that hose that can be changed out for tubing is a good idea.

Billski
 

Pops

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I couldn't find all the 5/16" fitting I needed so I used 3/8"dia fuel lines on the JMR. Fuel flow test was 37 GPH with min fuel. Over kill, ( Cont C-85 engine ),for any engine that I could put on it. 1/4" dia lines would have been to small. Fuel flow test at 18 degree AOA, more than required with the airfoil.

Bob Barrows uses 3/8" fuel lines with the Lyc- 540 on the Bearhawks. Fuel flow depends on dia of tubing, fuel line resistance in fitting and bends and fuel head.
If I remember correctly the fuel flow test is 150% of the WOT fuel used at the highest AOA possible.
 
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Marc Zeitlin

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...and the 43.13 suggests the lines it was built with are too small.
Do you have a pointer to what section of AC43.13-1B might suggest that?

All canard aircraft (with engines from O-200's to O-540's) use 3/8" tubing/hose for fuel feed lines, and none have any fuel flow issues with respect to restrictions to flow.
 

Mad MAC

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If you have doubts about it, do a fuel flow test. Fuel flow should be 1.5 x the maximum continuous fuel flow. Ensure the line where it is disconnected at the carb is open to atmospheric pressure at the attachment to the carb (stops it siphoning).
 

rsrguy3

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Yes we're looking at the 150%figure. We're also looking at the stc a friend has for the 220 frank on a his Stinson, it requires 1/2".

The aircraft was completed in 03 and the hours were never Flown off, I'm pretty sure the engine was never properly broken in either. Lots to unpack there.

The gut-o-meter is telling me the more extreme aoa's on the zenith could be an issue with 3/8" line.

For right now we'll r&r 1/2" or whatever dash it works out to from the tank to the root, and use proper flex line from there to the 3/8" hard lines in the fuse for our flow test.

The hard lines weren't even flared to hose barbs just hose slipped on and clamped (with signs of leakage).

I'm probably wrong but I'm sure the rag wing pipers I've worked on had short lengths of rubber hose terminated at barbed fittings..

I'm sure this kind of install is common in ex-plane ville, I guess my surprise is misplaced as I thought a DER would have called bravo Sierra.
 

TFF

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It’s not a DAR problem in the US. They might not like it, but it’s your experiment. They only care if the clamp is tight.
 

Pops

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If the fuel flow is marginal as some C-172's with the Lyc- 360 conversion a backup electric fuel pump is required. By daughter's 172 with the Bush Conversion for the L-360 required the backup electric pump.
 

Pops

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It’s not a DAR problem in the US. They might not like it, but it’s your experiment. They only care if the clamp is tight.
I wish that was true. I have a friend in WY that could change your mind.
 

TFF

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The question is, did he get a second DAR? Not to go behind the back, but I want a second opinion if I put in that much work in. If I think it’s good, it’s worth it. If some anomaly from standards is there, pull out the calculator and prove it’s still safe. If not, you agree with the first by default. If I was stuck with this problem, I would make sure whoever is in charge of the DARs knows beforehand that you did not believe you had a fair shake and are not trying to slip by.
 

Map

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The length of the fuel lines from tank to engine is also a factor. The longer the lines are, the more resistance there is to the flow and the bigger should be the diameter.
If there is any chance of relative movement between wing tank fitting and fuselage (there practically always is), a short piece of flexible hose should be used before switching to a hard line. A hard line connection may break over time.
 

Pops

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The question is, did he get a second DAR? Not to go behind the back, but I want a second opinion if I put in that much work in. If I think it’s good, it’s worth it. If some anomaly from standards is there, pull out the calculator and prove it’s still safe. If not, you agree with the first by default. If I was stuck with this problem, I would make sure whoever is in charge of the DARs knows beforehand that you did not believe you had a fair shake and are not trying to slip by.
FSDO says you can't go DAR shopping if one DAR doesn't like some rivets that are not perfect and turned it down and sent in a rejection slip to the FSDO office. DAR said they were safe along with a couple of IA's. But, he rejected it because some are not perfect. FSDO office says its the DAR final word and can't take it to any other DAR. It will probably get scrapped.
The DAR is trying to inspect to Certified Standards, not Safe Operation and the FSDO seems to be OK with it.
 
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TFF

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Not DAR shopping. That’s why I would contact above FSDO first and call foul. The next DAR doesn’t have to certify, but if he does say it’s good, a review at the top needs to happen to see why there is a difference.

The issues have been loaded into a database so the next person doesn’t miss it. This is not a fight of trying to get something over on the last DAR, this is a fight about consistency.

Cost wise, it might be a fight. I met a local that had to get one of the state senators to tell the FAA they had to make a decision on his medical instead of limbo of more testing please. That is hard to get in at that level. I would want this case to end up in a training class if I wasn’t going to get to fly my plane. Make them work as hard on this case as I did on the airplane.

No emails. Real paper. Has to get scanned and goes into a file cabinet. Emails just stay on a computer. Make it sticky.
 

Pops

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We have been friends for over 20 years and this is the third homebuilt for him. He is so upset I believe the airplane will be scrapped and he will quit flying. I have seen his other builds and they may not have the nicest paint jobs on them, but his work is very, very safe. He said two other IA's has looked at the project says the same thing.
 
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Vigilant1

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Not DAR shopping. That’s why I would contact above FSDO first and call foul. The next DAR doesn’t have to certify, but if he does say it’s good, a review at the top needs to happen to see why there is a difference.
In the real world, inhabited by us fallen humans, it seems unlikely that DAR 2 would over-rule DAR 1. The incentives are all aligned for him to agree with DAR 1. They surely know each other and probably want to remain on good terms professionally. DAR 2 will know of the issue and know the FSDO is aware of it. Will DAR 1 "repay" DAR 2 next time he gets the chance? If the work ever >does< fail, DAR 2 is squarely to blame, and the issue is fully documented, served up on a plate for the inquiry board. And which course of action makes the FSDO's job easier (reference your comment above)? In all, why would DAR 2 go through all that just to save some builder, a guy who he may never see again and who has no authority over him, a bit of re-work effort?
Now, if the situation were different and DAR 2 was being called to re-look something DAR 1 had approved that was now suspected of being unsafe, DAR 2 has a big moral obligation and a professional interest (liability) to disagree with DAR 1 if he thinks he's wrong. Going the other way, not so much.

Unfortunately, I think that's just the way things are set up. There's no impartial judge and no advocate for the aggrieved builder.
 
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Pops

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I don't like the whole DAR system. No checks and balances.
You are correct. I really don't see any good end for this.
 

TerryM76

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Previously found in 14 CFR Part 23.955 FUEL FLOW

(b) Gravity systems. The fuel flow rate for gravity systems (main and reserve supply) must be 150 percent of the takeoff fuel consumption of the engine.

(c) Pump systems. The fuel flow rate for each pump system (main and reserve supply) for each reciprocating engine must be 125 percent of the fuel flow required by the engine at the maximum takeoff power approved under this part.


While not pertaining to Experimental, it is still good guidance.
 
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