Gerry,

Yes, there is a lot of economy to be had by leaning to peak, or even LOP. GAMI injectors will further improve the fuel flow slightly. All three techniques, ROP, peak, and LOP are approved by Piper on the 310 hp Turbo Navajo. At 75% power, at peak EGT, the fuel flow drops to 30.6 gph. Pretty good economy. LOP, as you know better than I do, there is an incredible potential to increase the MPG's. I haven't completely dismissed the Turbo Navajo. In fact, it might be my only chice. According to the POH, the long lockers do mess-up the performance somewhat.

If you need a pdf PA-31 POH, let me know.

KW

You are comparing planes at different weights.

Further up, someone involved in the attempt to develop the STC is telling you that the 300s performance was 'marginal at best'. For the application they were talking about, requiring lots of short hops with a regulatory requirement (at the time) for a second engine, eliminating the turbos may have been a worthwhile project. Unless you have a really unusual usage pattern for a private aircraft, I just dont see that there is any payback on removing the turbos.

If you want to spend money, hire a DER and follow Dougs recommendation above to hang a 330hp IO580 on a Navajo. For that project, dont start out with the 310 but a 325 and get it certified on a known icing airframe. There are several thousand Navajos out there, you may even be able to sell a couple of copies of that STC.

By the time you are done hanging different engines on a Navajo, you would probably be better off buying a high-time Caravan.

Krzystof,

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.

Sorry, I just don't "get it".

Jgreen

Jesse,

I also think running those Turbo Lycomings LOP, an approved technique, would be very efficient. By the way, what's OP?

KW

I would certainly like a pdf copy of a PA-31 POH. You can pm me or email me at gparker@pmkc.com.

Just buy a Beech58 if you want to stay normally aspirated.

Gerry,

I just sent both of them to you.

KW

Just buy a Beech58 if you want to stay normally aspirated.

That would be you, "Original Post"

KW,

Do you own a 310 Navajo now? You are referencing performance info for the turbo Navajo but it seems like its all coming from the 310.

I have a 350 Panther Short Fuse Navajo and the performance is considerably better than what you have posted. I only cruise these engines LOP as they are powerful and economical...and its in the POH! 197ktas on 32.5gph at 12,000 with 2,000 lbs of fuel and pax on a recent trip. Crank up 750HP at 10,000'DA (Pagosa Springs in Summer) and a 1,700lb payload comes off the ground in 2,500' with an initial ROC of 1,800fpm.

You've received some good advice in this thread. I personally would avoid an NA Navajo.

That would be you, "Original Post"

Hi Jesse,

I don't own one, but I am looking, and monitoring the market. Back in May I contacted the seller of a Canadian Navajo 600 (normally aspirated 300 hp engines), and received the airplane documentation, but soon afterwards they informed me that they sold it.
The performance numbers are coming straight out of a 310 hp Turbo Navajo POH, and a 300 hp Normally Aspirated Navajo POH.
I think a Panther would be too much of an airplane for my purpose, and if I wanted that much power, I would just get a Mojave, pressurized and all, and get over with it.

KW

There have been previous discussions about the Navajo on this site. It would get me wherever I and my family want to go with payload and space to spare. Based on comments from prior owners, I thought that there is some value in the 310 vs. the 325. However, when I started browsing for sale ads, I found that most of the 310s on the market had very high airframe hours, were old in years and looked quite rough. Many had canadian registrations and lots of charter hours. Otoh, there was a good number of nicely updated 325s and Panthers on the market, most probably from owners and businesses who upgraded to a turbine.

Given the poor ROI of most aircraft refurbishment projects, you are probably better off buying an updated aircraft, fly it and see whether it fits your needs rather than buying a runout 310, spending money on a field approved conversion and ending up with a oddball of a plane that may or may not sell if you decide that it is not the right tool for the job at hand.

Florian,

It seems like there are many more, nice, low time 325's than 310's, indeed. I don't want a runout 310. If it's a 310, I want it as good as they come, then do a conversion on it, or maybe, just maybe, keep it a turbo. Right now there is one very nice, well maintained, low time, fully equiped, built in the eighties, 310 hp Turbo Navajo, for sale for under $150,000.
A Normally Aspirated Navajo on the other hand, would probably require a ground-up rebuild, spanning 3 to 4 years, and costing probably upwards of $200,000 to $250,000, assuming I did a lion's share of the work myself, plus the acquisition of the subject airplane for another $75,000 to $85,000 or more, or a lot more, if you could find one. In the end you would have almost a brand new airplane though.

KW

Hi Mark,

Thanks for another awesome, informative, and illuminating post. I will get back to both of them soon.
You, or anybody else, can post here about the Beech 18 or anything else.
Happy New Year to you, and all Beech Talkers.

KW