Initial Pirep of Aeromotors overhauled Dukes Fuel Pump.

[Shadrach]

Greetings folks,

Given my anecdotal experience with the short life span and marginal performance of the Dukes 4140-00-19 electric fuel pumps, I thought I would give y'all my initial impression of the newly overhauled unit I received from Aeromotors LLC (Browntown, WI).  After speaking with Ole Bartlett (company owner) about the methods used to overhaul this pump, I am hopeful that this recently overhauled pump will last a long time. He explained the many enhancements that they made to the original Dukes design. I am going off memory but those enhancements include the following:

1) The old design utilized a sleeve bearing for the drive assembly located on the wet side of the pump (fuel lubricated).  The new design utilizes a sealed bearing on the dry side of the pump.

2) The old design used a sintered stainless cam ring which worked fine with carbon vanes. At some point Dukes "upgraded" to Nylatron (plastic) Vanes to prevent pieces of broken vane from entering the fuel system. The new Nylatron vanes did not interact well with the sintered stainless cam ring and over time the vanes would strip material from the cam ring that would then become embedded in the vanes essentially transforming them into a cutting tool. Aeromotors uses a nickel alloy cam ring.

3) Motor drive shaft coupling - Dukes used several different couplings over the years none of which were particularly reliable and caused alignment issues. Aeromotors redesigned the coupling to correct this issue.

There are likely other upgrades that I am unaware of, but I think Ole explained most of the old designs weaknesses and how they were remedied.  He's a very nice, down to earth gentleman who was happy to take the time to explain why he believes his products are the best.  The new design has been bench tested for 1000s of hours including nonstop runs of 200+ hours and dry runs in excess of 10 hours. No wear or degradation in performance was noted during testing wet or dry.

Operationally I have noticed the following differences with the new pump:

1) There is almost no audible change in load on the new pump. It starts and spins at what sounds like a constant RPM.

2)  It sounds robust and builds fuel pressure much faster than it did previously. 

3) Pre-overhaul, my pump sounded like it was laboring from the first day it was installed.  It was wheezy, slow to build pressure and would surge and wane during the prime.  Those symptoms are gone.

Time will tell if the new pump is as robust and reliable as it initially appears. I am not sure if I will have to shorten my prime count due to the increased pump volume.  I typically depart with the electric fuel pump on in aircraft so equipped. I had modified my SOP and stopped using the pump during take off because it had repeatedly demonstrated its fragility in the past decade.  I now feel comfortable using the pump during takeoff and landing operations.  I am also confident that it will serve as a reliable back up in the unlikely event of a mechanical pump failure. Something I was always dubious about previously.

[lukejb]

This sounds like a really good solution.  My boost pump sound like it is struggling and going to need an overhaul or something soon.  Do you mind sharing the cost for the overhaul?

[Shadrach]

22 minutes ago, lukejb said:

This sounds like a really good solution.  My boost pump sound like it is struggling and going to need an overhaul or something soon.  Do you mind sharing the cost for the overhaul?

$450.00, which is less than half of what QAA ($1350),  CJ Aviation ($1050) or Spruce ($1481) are charging for an Overhaul exchange without any upgrades. It's a no brainer.

http://www.aeromotorsllc.com/aeromotorsllc/

Edited February 5, 2019 by Shadrach

[Igor_U]

Aeromotors OH'd my pump 2.5 years ago. It is still running strong, same speed and fuel pressure.  

[jaylw314]

14 minutes ago, Shadrach said:

$450.00, which is less than half of what QAA ($1350),  CJ Aviation ($1050) or Spruce ($1481) are charging for an Overhaul exchange without any upgrades. It's a no brainer.

http://www.aeromotorsllc.com/aeromotorsllc/

What was the turnaround time?

[Shadrach]

 They turned it in a day but I don’t think they guarantee that. The only inconvenience is that you must send a return shipping label and a check In the box when you ship it out. I did UPS ground both ways. I think I shipped it out on Monday and got it back that Thursday. I think they will do an exchange if they have the right model pump in stock.

Edited February 5, 2019 by Shadrach

[Bob - S50]

They did ours about 5 years ago.  Still working great... even though we occasionally forget to turn it off after takeoff.

[Yetti]

You would like to think that "certified" and lots of paperwork would lead to a higher quality longer lasting product.  In the business I am in where we talk about collecting data and then predicting failure, you would think that would be part of the certification process.  

[sgrooves]

They overhauled my Weldon pump last year. Still running strong. Took 2 weeks because a parts supplier had a 1 week employee holiday....

[1964-M20E]

They did mine a number of years ago ans still going strong.

 

 

[Mark89114]

1 hour ago, Yetti said:

You would like to think that "certified" and lots of paperwork would lead to a higher quality longer lasting product.  In the business I am in where we talk about collecting data and then predicting failure, you would think that would be part of the certification process.  

You would think....we seem excited about vacuum pumps that last 500 hours, speed brakes that need overhaul after15 hours of use, gyros that aren't worth a scheisse, and a simple fluid pump that can't even last 1000 hours.  I have industrial equipment that runs thousands of hours before we do anything to it.  Just grin and bear it I guess. 

 

[ArtVandelay]

I have industrial equipment that runs thousands of hours before we do anything to it.  Just grin and bear it I guess. 
 

But airplane equipment has to be relatively light, industrial equipment can be made of steel and be as robust as you can make it, airplane equipment is always a compromise.


Tom

[carusoam]

2 hours ago, Mark89114 said:

You would think....we seem excited about vacuum pumps that last 500 hours, speed brakes that need overhaul after15 hours of use, gyros that aren't worth a scheisse, and a simple fluid pump that can't even last 1000 hours.  I have industrial equipment that runs thousands of hours before we do anything to it.  Just grin and bear it I guess. 

 

Similar to speed brakes....You left out the landing gear drive system that gets about an hour or two of use in its lifetime... before the spring gets replaced with a chance of being replaced with a faulty one... no back clutch spring...?

keep in mind the gear and speed brake motors only actually operate for a few seconds each flight.

Is the certification process getting overhauled, like the part 23 plane certification is getting..?

Great write-up, Ross!  Including speaking with the Key guy.... my favorite kind of conversations in aviation! 

Thanks for sharing the details.

Gents,

The certification process puts the decision making into the wrong hands... has done it this way since the beginning of time... modern manufacturing including how the FDA works is slowly putting the certification process into the hands of the people that know how stuff is supposed to be designed and made...

Seeing how Ross’s pump got tested for the most likely failures... long runs and dry runs.... by the guy who knows pumps the best... looks like we are going to be in good hands going forwards...

Ross, See if they have used serial numbers on everything with traceable lot numbers and other evidence of good manufacturing procedures... (GMP)  this would be the evidence of knowing what is in there in the unlikely, out possible, event that it needs to be recalled...

Computer science has modernized manufacturing to an incredibly high level... making good processes even better... for less. 

Best regards,

-a-

[Shadrach]

2 hours ago, ArtVandelay said:

But airplane equipment has to be relatively light, industrial equipment can be made of steel and be as robust as you can make it, airplane equipment is always a compromise.


Tom

I would put any modern auto fuel pump  against the Dukes for both lightness and reliability.

[ArtVandelay]

I would put any modern auto fuel pump  against the Dukes for both lightness and reliability.

Key word is modern. I see no point in complaining about a pump designed in 1960s not being as good as today’s version.
You can say that about the whole plane.


Tom

[Shadrach]

24 minutes ago, ArtVandelay said:

Key word is modern. I see no point in complaining about a pump designed in 1960s not being as good as today’s version.
You can say that about the whole plane.


Tom

The complaint is that a modern pump cannot be retrofitted legally and easily. 

You must’ve missed the story I told in an earlier thread about the 47-year-old Jaguar E-type that had not run in 20 years. I put a battery in the car and the pump came to life immediately.   It’s a nearly 50-year-old Lucas (not known as a benchmark for electronic reliability) pump. That car only has 51,000 miles on it but it’s still on the original pump. The Mooney is on its fourth.

Edited February 6, 2019 by Shadrach

[Andy95W]

Not to play devil's advocate, too much, but isn't the deal with automotive fuel pumps to just get the gas, at low pressure, to the engine?  The engine driven pump then gets the required psi for the fuel injection to work.  

The electric pump on the IO-360 has to be a fully functional backup to the engine driven pump in case of inflight failure, and must put out 30psi on its own.

The electric pump on the carbureted engines only have to put out 6psi, and seem to last much longer.

[EricJ]

5 minutes ago, Andy95W said:

Not to play devil's advocate, too much, but isn't the deal with automotive fuel pumps to just get the gas, at low pressure, to the engine?  The engine driven pump then gets the required psi for the fuel injection to work.  

The electric pump on the IO-360 has to be a fully functional backup to the engine driven pump in case of inflight failure, and must put out 30psi on its own.

The electric pump on the carbureted engines only have to put out 6psi, and seem to last much longer.

Automotive fuel pumps generate a lot more pressure than the IO-360 fuel injection needs.   Typical auto fuel injection systems are anywhere from 40-80psi,  and are the only pump that supplies pressure.   There is no engine-driven pump on most cars, (the newer direct-injection systems are an exception as they require *much* higher pressures).   The system pressure on my airplane (IO-360) seems to run around 22psi or so.   Automotive pumps flow a lot more, too, when they're feeding something making 300-500hp as compared to 200hp or so.

On the other hand, most auto pumps are the sole pump rather than boost pumps, so they don't have to be have pull-through capability so that a mechanical pump can draw through them.

But I am generally in agreement that the technology in most airplanes has been progress-inhibited by excessive qualification standards and a smaller market.   Both forces have conspired to keep much of GA at a technology reliability level that was state-of-the-art 30+ years ago.  We don't get the benefits of many  modern advancements that would likely improve both costs and reliability.

[Andy95W]

Eric- had no idea- thanks!  I've hated working on cars ever since they got more complicated than my old 1967 VW Karmann Ghia.