29 Mar 2024, 05:45 [ UTC - 5; DST ]
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Post subject: Turbo Navajo to Normally Aspirated Navajo Conversion Posted: 28 Dec 2015, 01:41 |
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Joined: 09/05/13 Posts: 125 Post Likes: +7
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Hi Folks. We started talking about this subject on the Beech Twins forum, and I am sort of trying to 'move' it to this forum.
KW
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Post subject: Re: Turbo Navajo to Normally Aspirated Navajo Conversion Posted: 28 Dec 2015, 02:03 |
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Joined: 09/05/13 Posts: 125 Post Likes: +7
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Just to digress for a minute. Mark, or anybody else, would you know who does the Turbo Navajo to Normaly Aspirated Navajo (Navajo 600) conversion? Any lead will be much appreciated.
KW
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Post subject: Re: Turbo Navajo to Normally Aspirated Navajo Conversion Posted: 28 Dec 2015, 02:18 |
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Joined: 09/05/13 Posts: 125 Post Likes: +7
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IO-540s.
Last edited on 28 Dec 2015, 11:38, edited 1 time in total.
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Post subject: Re: Turbo Navajo to Normally Aspirated Navajo Conversion Posted: 28 Dec 2015, 08:31 |
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Joined: 05/23/08 Posts: 6059 Post Likes: +702 Location: CMB7, Ottawa, Canada
Aircraft: TBM - C185 - T206
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Why would anybody want that? Piper had it at first and it was discontinued. Nobody wants a lower performing aircraft.
_________________ Former Baron 58 owner. Pistons engines are for tractors.
Marc Bourdon
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Post subject: Re: Turbo Navajo to Normally Aspirated Navajo Conversion Posted: 28 Dec 2015, 11:33 |
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Joined: 09/05/13 Posts: 125 Post Likes: +7
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First of all let me just say that I spent most of my flying in the thirties, twenties, and teens. When I get back into light aircraft, I won't really care to fly above ten thousand feet, or wear an oxygen mask. I also like to live at or near sea level.
There are several reasons I am interested in this coversion. The engines are lighter, cheaper to overhaul, simpler, run cooler, have longer TBO, higher dispatch reliability - one item less to break - burn a lot less fuel, especially on take-off and climb. The performance below ten thousand feet is very similar of both the turbo and normally aspirated Navajo.
KW
Last edited on 28 Dec 2015, 11:42, edited 1 time in total.
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Post subject: Re: Turbo Navajo to Normally Aspirated Navajo Conversion Posted: 28 Dec 2015, 12:32 |
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Joined: 03/30/10 Posts: 490 Post Likes: +225 Company: Parker Flight Training Location: Georgetown, TX (KGTU)
Aircraft: 2018 Other
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The first Navajos in 1967 were equipped with normally aspirated IO-540's rated at 300HP. Although I never flew one, the talk around the airport was that it was a dog, especially single engine. The turbocharged model at 310Hp, in which I have over 500 hours, is quite a nice airplane and I suspect the CR model (325HP) is even better. I usually flew 7-10,000 feet and only went higher when necessary. All turbocharged Navajos were sold with high capacity O2 systems so I could operate at higher altitudes if I chose. My kids were small but never objected to wearing the mask. I made several trips to the west coast and really appreciated the turbos on that trip.
The fuel burn might be a bit lower at cruise but the speed might also be slower. As for takeoff, probably not a lot of difference in fuel flow at sea level. However, you are correct about the heat - the tightly cowled Navajo runs hot at high power settings and hot starts can be a real challenge.
Resale would definitely be a problem with a normally aspirated Navajo. I don't know if there are any still around but have never seen one for sale since the early days. If memory serves, someone offered an upgrade to the TIO-540 for the early models.
Just my tuppence worth.
_________________ Gerry Parker, CFII, MEI Insurance Approved Training 58P, C340/414/421, PA31 KGTU (Georgetown, TX)
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Post subject: Re: Turbo Navajo to Normally Aspirated Navajo Conversion Posted: 28 Dec 2015, 14:23 |
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Joined: 08/03/08 Posts: 16179 Post Likes: +8782 Location: 2W5
Aircraft: A36
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Username Protected wrote: The first Navajos in 1967 were equipped with normally aspirated IO-540's rated at 300HP. Although I never flew one, the talk around the airport was that it was a dog, especially single engine. I have heard the term 'lead sled' used for those. The PA31 got the turbo to achieve the required performance, not for high altitude ops or pressurization. Spending 100k+ to reduce performance and make the plane a one-of would seem an unusual step. Putting the 350hp chieftain engines on the 'short' navajo seems to be a popular mod.
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Post subject: Re: Turbo Navajo to Normally Aspirated Navajo Conversion Posted: 28 Dec 2015, 15:26 |
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Joined: 03/17/08 Posts: 6052 Post Likes: +12360 Location: KMCW
Aircraft: B55 PII,F-1,L-2,OTW,
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IO-580's anyone??? 330 Hp, no turbo, should be a bolt in replacement....
I would not see why a straight Navajo with NA -580 would be hard to sell...
_________________ Tailwinds, Doug Rozendaal MCW Be Nice, Kind, I don't care, be something, just don't be a jerk ;-)
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Post subject: Re: Turbo Navajo to Normally Aspirated Navajo Conversion Posted: 28 Dec 2015, 15:38 |
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Joined: 11/20/14 Posts: 6452 Post Likes: +4524
Aircraft: V35
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I believe there were some normally aspirated Queen Air conversions that found market acceptance - Excalibur conversion with 720's I believe.
If the goal is to carry a big load in a big cabin with normally aspirated engines, that would seem to fit the bill.
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Post subject: Re: Turbo Navajo to Normally Aspirated Navajo Conversion Posted: 28 Dec 2015, 18:01 |
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Joined: 08/03/08 Posts: 16179 Post Likes: +8782 Location: 2W5
Aircraft: A36
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Username Protected wrote: I believe there were some normally aspirated Queen Air conversions that found market acceptance - Excalibur conversion with 720's I believe.
If the goal is to carry a big load in a big cabin with normally aspirated engines, that would seem to fit the bill. Someone posted about owning one here. Very impressive performance. A whole fleet of them is operated by Bemidji air flying parcel contracts with a mini-hub at MSP. I believe their DOM is a member here. Is there any normally aspirated IO540 that mkaes more than 300hp ?
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Post subject: Re: Turbo Navajo to Normally Aspirated Navajo Conversion Posted: 28 Dec 2015, 21:38 |
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Joined: 11/25/11 Posts: 9168 Post Likes: +17159 Location: KGNF, Grenada, MS
Aircraft: Baron, 180,195,J-3
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Username Protected wrote: Sounds like you need a B55 Krzystof, I'll go with Max, if you don't want turbocharging then buy an airplane designed/built without it. What minimal savings you might find from lower fuel consumption would take thousands of hours of use to overcome the expense of such a conversion. As for "lower temps, higher dispatch" really? The turbo Navajos seem to run regularly to TBO with an absolute minimum of maintenance. Sorry, I just don't "get it". Jgreen
_________________ Waste no time with fools. They have nothing to lose.
Last edited on 28 Dec 2015, 23:47, edited 1 time in total.
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Post subject: Re: Turbo Navajo to Normally Aspirated Navajo Conversion Posted: 28 Dec 2015, 23:31 |
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Joined: 11/20/14 Posts: 6452 Post Likes: +4524
Aircraft: V35
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The OP may also be interested in all the GAMI data from running the Navajo engine on a test stand LOP. It may be possible to run the existing Navajo engines with the cool CHTs and lower fuel flows the OP is looking for, thus solving the problem without an engine change. There are probably still slots for the March 2016 live APS class in Ada, and the online APS is always available. I would also bet that Deakin or Atkinson would be reachable here on BT for a quick question about Navajo engine ops.
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