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ArtVandelay

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Dukes vs Weldon.  The old Dukes would grenade their plastic parts and then send them on downstream to the engine.  So there is an SB to add a filter to keep that from happening.  It is the silver thing in the lower left of the top picture.  I am glad I found that I have a Weldon.   Upon fix repair replace.  Make sure the check the finger screen on the servo and the inline filter.  Someone will be along to post the SB.  And now the AMUs to switch to weldon don't seem so bad do they.

Edited by Yetti
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Part of the Weldon conversion back in the 1990s involved new tubing that was installed. Based on cnoe's message above, if they sell a direct drop in, I would jump on it. The impeller is not plastic on a Weldon. I also stopped by the Weldon booth at Oshkosh (poor guy was all alone) and talked about the Weldon pumps. Seemed to have a good handle on the right way to build a pump.

I also can't tell you the number of times I have flown with Mooney owners as a safety pilot and watch them leave the boost pump off. When I ask why, I get the "It's a Duke" comment. Sure it is a startup pump and one if the engine driven pump dies, but why cut corners on something that will keep you airborne?


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My Duke pump was overhauled by Duke Inc back in 94, and mine is 1499-00-19, notice no A, so don't know if non A is candidate for Weldon swap. I only use it for start and takeoff, assuming 50 flights per year, that's maybe 2 hrs per year, or 46 hours of operational, assuming POs used it the same way. But even though not operating it's still in the path of fuel flow, and seals are probably more time dependent than hours used. If this fails in short time, I will go swap route next time.

 

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  • 1 month later...
  • 1 year later...

Looks like I found out the hard way that the Dukes are not rated for continuous use... I had been turning it on during takeoff as it seemed the fuel return was keeping the CHTs a few degrees cooler so I wouldn't pass 400F.

Went to start today and the pump went WAH for 1/2 second then nothing. Looks like I'm in the market for a new pump.  @teejayevans how's your Aeromotors rebuild holding up? 

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Looks like I found out the hard way that the Dukes are not rated for continuous use... I had been turning it on during takeoff as it seemed the fuel return was keeping the CHTs a few degrees cooler so I wouldn't pass 400F.
Went to start today and the pump went WAH for 1/2 second then nothing. Looks like I'm in the market for a new pump.  [mention=11849]teejayevans[/mention] how's your Aeromotors rebuild holding up? 

So far so good, including forgetting to turn it off on a 2 hour cross country.
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3 hours ago, SantosDumont said:

Looks like I found out the hard way that the Dukes are not rated for continuous use... I had been turning it on during takeoff as it seemed the fuel return was keeping the CHTs a few degrees cooler so I wouldn't pass 400F.

Went to start today and the pump went WAH for 1/2 second then nothing. Looks like I'm in the market for a new pump.  @teejayevans how's your Aeromotors rebuild holding up? 

The mixture knob is for keeping things cooler.  A couple of PSI above the Mechanical pump is not going to do anything.

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1 hour ago, Yetti said:

The mixture knob is for keeping things cooler.  A couple of PSI above the Mechanical pump is not going to do anything.

On TCM engines there is actually a fuel return line that returns unused warm fuel to the tank.  It has kind of a radiator effect.  I’ve found it lets me cool my CHTs by 10-20F when I have that extra couple PSI.

 

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6 hours ago, SantosDumont said:

Looks like I found out the hard way that the Dukes are not rated for continuous use... I had been turning it on during takeoff as it seemed the fuel return was keeping the CHTs a few degrees cooler so I wouldn't pass 400F.

Went to start today and the pump went WAH for 1/2 second then nothing. Looks like I'm in the market for a new pump.  @teejayevans how's your Aeromotors rebuild holding up? 

There is no fuel return line in fuel-injected Lycomings, that is only in Continental fuel-injection.

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3 hours ago, SantosDumont said:

On TCM engines there is actually a fuel return line that returns unused warm fuel to the tank.  It has kind of a radiator effect.  I’ve found it lets me cool my CHTs by 10-20F when I have that extra couple PSI.

 

You have a Mooney 20F listed in your profile.   Might want to update that if you have TCM in your plane.

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8 hours ago, Yetti said:

You have a Mooney 20F listed in your profile.   Might want to update that if you have TCM in your plane.

Yup. M20F with the ModWorks STC. Has all the speed mods and a TCM IO-360-ES. I’ve heard there are two planes with this STC, I don’t know who has the other one. 

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  • 2 weeks later...
1 hour ago, SantosDumont said:

Aeromotors now charges $450 to overhaul the Dukes pump.  Got mine back on Thursday, put it in.  It seems louder than the original pump, but other than that works as advertised.

Iirc it’s IRAN not overhauled. 

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  • 3 weeks later...

My dukes failed during yesterday's prime for an early morning flight. the pump started to prime in the usual manner and then the made a quick pitch change and was running what sounded like a higher RPM.  I surmise that the impeller failed and the now  unloaded motor is turning faster. This pump was IRAN'd just under 8 years ago. The plane has accumulated approximately 475hr since it was in service.  A generous account of its actual cumulative run time in service is likely about an hour (I do not use it for anything other than priming).  This is its 4th failure in the 3200hours on the airframe.  I do not understand how an "aircraft grade" components can be so fragile and unreliable. The regulatory environment should be ensuring the best and most reliable.  I'm trying to contrast this pumps reliability with that of my autos.   I can't compare service intervals because I have never had an automotive fuel pump fail.  I recently unearthed a 1971 Jag E-type.  This car was last started by yours truly in 1995 and has been stored indoors but without climate control since then. I put a battery and fuel in the car and turned on the ignition. Sure enough, after 23 years dormant the pump came on and delivered gas to the carburettors. 

I think it's appalling that 47 year old system comprised of Lucas and British Leyland components is more robust than what I am compelled to install on my aircraft.

Edited by Shadrach
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17 minutes ago, Marauder said:

I know when my Duke’s failed it was the plastic impeller that did it in. I went with the Weldon and haven’t looked back.


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I am considering that option.  There are a great many differences in aircraft and automobiles. Sending pressurized fuel to the injection system or carburettor is an area of over lap.  I am confident that there is a reliable auto pump out there that would work very well and allow aircraft owner't the rare benefit of economy of scale.  Perhaps I'll find a suitable pump and start STC process!:D

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I just spoke with Ole (sp?), one of the owners of Aeromotors.  He spent a solid 20 mins on the phone with me detailing all of the upgrades that Aeromotors has made to the Dukes design. It's primarily materials changes but there are also a few design mods that improve reliability. The original duke's design utilizes a sleeve bearing on the rotor shaft that needs fuel for lubricant.  This has been replaced with a sealed ball bearing that has been relocated outside of the rotor cavity (Dry).  The shaft seals have been upgraded from O-Rings to Lip Seals (crankshaft seals are a type of Lip Seal) in addition to a host of other small changes and refinements.  Ole told me that he personally ran one of their overhauled pumps dry for a continuous 10 hours with no sign of wear afterward.  He then ran that same pump wet for 200hrs continuous with no wear.  Aeromotors also overhauls Weldon pumps which he said are robust but have their own set of issues that Aeromotors has addressed.  The impression that I was given is that any advantages to switching to Weldon have been mitigated by the minor changes Aeromotors has made to the Dukes.  I came away from the conversation feeling that either pump should be far more reliable after being overhauled by Aeromotors. I'm hoping that's the case because I accepted his offer to build an exchange for me so that they'd have next day turn around when my core arrives.  Ole seems a genuinely nice guy, if Aeromotors does what he says it does then this is a big win for folks that have been living with the fragility of the Dukes pump. Cost for OH is $450 before shipping. 

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