Hi Mark,

According to the -310 POH, some performance differs with the long nacelles, but especially single engine climb performance suffers, where the rate of climb decreases from 245 fpm to about 210, a significant reduction at this already marginal performance level. I like the short nacelle look.
I read about the Millard family misfortunes, sad. C-GMLJ and C-GAFF were the airplanes for sale on Controller during about the first six months of 2015. Around May I contacted the seller of C-GAFF, they sent some of the airplane's documentation to me, and told me that the airplane is still available for sale, as one potential buyer is having a problem arranging financing. Soon afterwards they informed me that this person's financing went through, and they sold it. C-GMLJ was last seen on Flight Aware heading down to Nassau, while C-GAFF is plowing the Canadian skies. Interestingly, C-GAFF has three bladed props, in my opinion giving it more "curb appeal".
I am serious about buying one, but am still evolving, and not sure whether I should attempt to get a Normally Aspirated, original or converted one, and get involved in a restoration project spanning years, and a lot of dough, as I think it would be very unlikely that I could find a really nice, ready to fly normally aspirated airplane, if I can find one at all that is, OR for about $150,000 I can buy a very nice -310 Turbo, low time, very well maintained (to be verified of course), fully equipped, eighties vintage, and attempt a Field Approval or an STC, or just keep it Turbo.
How expensive, and time consuming would a Field Approval, or an STC be, what do you think?

KW

Hi Krzysztof,

Thank you for the thoughtful comments, and for posting the pic of C-GAFF. Noticed the tail of C-GMLJ in the background. As mentioned, I can help guide you toward some of these normally aspirated aircraft should you decide to do that... or steer you toward some turbo ships. At this point in the evolution of general aviation, with its' attendant escalating costs and hassles, I feel it would not be worth your time, money and trouble to convert a turbo Navajo back to normal aspiration. It is a marvelous plane, but you'd be miles ahead to find and purchase one already converted. As previously mentioned, unless you're going to convert a commercial fleet of Navajos, you would end up with a very negative ROI trying to tackle this conversion for a one-off 337 field approval. An STC would be even worse. And if you don't do it in a very aviation friendly FDSO district, they can run you out of patience and money. You could easily sell a plane like that if you needed to, but you'd never come close to recouping your investment. For starters, the IO-540-M1A5 (-300) has a different crankshaft than a TIO-540-A2B/C (-310), so you could plan on having to purchase or overhaul two engines just for starters. Of course, there are other differences, as well. By the time you've hung new engines, possibly put the heater mod on since it is opened up, as well as a myriad of other items you'll need to do, pay a DER for the engineering and paperwork, etc... you're going to easily have between $150-200K JUST in the mod itself, not including purchasing the airframe and getting it up to speed, possible interior, radios, maybe paint, etc... Do you see where I'm going with this? You can purchase a decent 1970's-vintage run-out for $50K, but by the time you're done with it, you could easily have over $300K in that one airplane -- that you could turn around and sell all day long for $150K. Or... you can go buy a good normally-aspirated or turbo Navajo for between $100-125K and tweak on it while you fly until you get it 'right'. Something else, about 2/3 of the normally aspirated fleet has deice... the rest are fair weather flyers. Good deiced turbo-Navajos are relatively easy to find. Not sure why you're only interested in 1980's-vintage, because the late 'C' model of the '80's is very similar to the straight turbo-Navajos and B & C models of the 1970's. About the only advantage I can think of is possibly in the instrument panel -- but it's going to cost you for that, and it's something you can deal with over time. You're probably going to want to change some of it anyway. I like beige or gray instrument panels over black ones myself, but I'm not going to pay an extra $100K+ for a plane because it has one. We'll just fix it when the panel gets upgraded. Of course, if you don't blush at those costs, then by all means... carry on. Newer is generally better -- but not always.

Again, it is not impossible, it just may not be worth the trouble [read: $$$$] unless you have others lined up to convert their aircraft and pitch in to pay for it. We ran into this trying to put rear passenger doors in Piper Aztecs and Cessna 320 Skyknights (converted by Colemill to normal-aspiration), so people could actually get in the rear seats without having to scale the Matterhorn. Whether you get a normally aspirated or turbo-charged plane, you're still going to end up having to tinker with it for several years until you get it where you want it... even if it "looks good" to begin with.

Best wishes in your search! ~~ Mark

My understanding of upgrade projects is that you want a runout with tired paint and interior but the best airframe you can find. Turbo lycomings can nickle and dime you to death with expensive hardware if you do a field overhaul. More than once, I have seen the recommendation to go with factory remans as they come with overhauled turbo and transition. If you are going to trade the engines as cores, all that counts is that they turn over with a wrench on the crank-shaft when they get to the factory.

The best deal is to find a plane that is 'good enough' and to spend your money on flying it.

Which of the Navajos have the dual magneto ? Is that something that can be remedied at overhaul time ? I remember something about an STC to that effect.

350HP IO540-J2BDs have the dual. J2Bs don't.

Yes. The one recently dropped from factory support. As noted above, they seem to be limited to the 350hp Chieftain and Panther conversions.

What an interesting thread... and I don't normally get into the non Beech planes.

But after having a Chieftain, this was interesting. I considered the NA Navajo at the time, but just not available. I think it would be a great plane for some applications, and keeping the operational cost in check.

One of the reasons I got rid of the Chieftain, is that for 2 people on board it just didn't make sense, and I was doing less and less "load hauler" trips, and even when I did, I footed most of the bill.

Had the NA plane been available, I could have easily just kept it.

The downside of the turbo'd plane what the costs... gas was high, the engine cost got brutally high and the maintenance was high. But if you NEEDED that cabin and load capability, it was hard to beat. I didn't like the dual "one shaft" mag either.

As for high altitude performance, the Chieftain wasn't that impressive. With the maximum manifold restrictions, it wasn't practical above 22K, and really wasn't that fast up there. It would scoot along pretty good in the mid to high teens, but had a drinking problem. (Had mine high many times)

Overall, for light load, cost, speed and range the B58 was significantly better, and that's what I ended up with.

But loved the Chieftain for the right mission.

How about a straight Aerostar 600 or 600A? 5,500 lbs. gross weight, add wing extensions and get another 200 lbs. Empty weight around 38, 3900 lbs. 165 gal. full fuel. 200 kts. sea level through 10,000, 30 to 34 gph. Plenty of room. Actually enough room to put a make shift bed in for long trips.

Hi Tom,

I did look at the straight Aerostar as well, very nice bird. However, once you look at the cabin of the short body Navajo, everything else pales in that regard. It's a very comfortable eight seat airplane. With six seats, a bar/galley in the place of the seventh seat, and a seat/toilet in the place of the eight seat, you'll have a mini airliner. Not as fast though as an Aerostar.
Thanks for your input.

KW

Hi Larry,

Guess what? With 14 built by Piper in 1968 and 1969, and six turbo conversions to normally aspirated power, and some of them lost in accidents, they are still not available. Finding one would be like winning a lottery. Finding a top notch one would be a Heavenly miracle. So if you want one, you have to take a turbo, and go through an ordeal of a Field Approval, or worst, an STC, as there apparently is no STC.
Originally I was looking at Twin Comanches, the original 1963 to 1965 version, and similarly to the Normally Aspirated Navajo, in order to have a really nice one, you would have to rebuild one up from, or almost from the ground up. As much as I like tinkering, and "turning screwdrivers", I am not looking forward to the daunting task of a complete restoration. So then I looked at none other than the beautiful Beech Baron B55. With it's 260 hp IO-470's, you can fly fast on higher fuel flow, or you could pull the power back, and just about match the Twin Comanche's fuel economy. Plenty of them on the market, some fully equipped for all weather operation, some in mint condition. Presto!
After monitoring the B55 market for a while, it started dawning on me that by "adding" just another meager 40 hp to the B55's 260 hp, I could be in the 300 hp, dream Navajo territory. In the mean time I looked at everything up to and including the B58, P58, a Mojave, and a Chancellor, the latter three being too much of an airplane for my purpose.
Thanks for your thoughts.

KW

Hi Mark,

Your preamble says it all.
$150,000-$200,000 for the mod., plus the airplane I am eying now another $145,000, plus about $15,000 for an electric air conditioning - the only item this airplane doesn't have - brings the grand total to $310,000-$360,000 of initial investment. If I don't bother with the conversion, $150,000-$200,000 would buy me 30,000-40,000 gallons of avgas at say an average of $5 per gallon. Assuming an average fuel flow of 26 gph, and 200 hrs. per year, that would fuel a turbo model for about 5.8-7.7 years. Interesting math.
I like Janitrol heaters, as you can plug your bird to an A/C outlet, and warm up your cabin before starting the engines. Also, I like the clean nacelle look, without the scoops, though it's interesting how the "Canada-Mod Heater" came about, in Cleveland! Same thing with the landing gear doors - I like them fully enclosed, and so I probably will skip this mod as well.
Speaking of Canadian mods, included in the paperwork I received from the seller of C-GAFF back in May, is a copy of a Canadian STC for this bird, done by Deca Aviation... This must be associated with Millard Air. I can't post it here as it is copyrighted.
The airplane that I am looking at right now is 1980's vintage, but I am not limiting myself to the eighties. It can be a B or a C model, or anyone starting at the 1967 model. Another airplane I am looking at is in fact a 1975, and another one a 1976 model. All weather capability, full anti ice/deice is essential. Grey instrument panel would be neat. Short nacelle it must be, as the long ones do "mess-up" the performance, indeed.
I do expect to tinker quite a bit. In fact, I enjoy "turning screwdrivers". I might even consider taking some A&P classes at the Teterboro School of Aeronautics, or at least learn how to work on my airplane.
Your IO-720 powered Chieftain is an interesting concept. I think some Chieftain operators would gladly swap those fire-breathing TIO-540's for the 720's.
Sadly, people like Mr. Millard, and Mr. Soloy, whose ingenuity and perseverance could have paved the way to more freely breathing IO-540-M1A5 powered Navajos, have left us for good.

KW

One thing to keep in mind, at the lower levels a normally aspirated plane will perform better than a turbo pressurized model. It is substantially lighter and turbos do take time to wind up.
You're really not going to see any improvement in speed until you get up to and above 10,000msl. However, the turbo models will always burn more fuel at all levels.

Last night I was comparing the normally aspirated vs. the turbo fuel flows. During full power take-off and initial climb, the normally aspirated Navajo burns about 48.5 gph, the turbo... staggering 69 gph, 20 gph more, while producing only 10 hp extra. I guess that's what happens when you pump 41" of manifold pressure into the engine. These numbers are out of the Piper and Lycoming manuals. You are correct Tom, turbo models always burn more fuel, or a lot more. I wonder how do the turbo-normalized models compare.

Just so we're reading off the same page here, most of the aircraft with the muff heaters (Aerocrafters [Bullock] mod), also keep the Janitrol heater, as well. Good redundancy... particularly inflight when your Janitrol breaker pops on the coldest flight. It's not a question of "IF". They are completely separate systems except for some of the ducting. The scoops you see on the bottom of Navajo cowlings have nothing to do with the heating system, they are for turbo intercooling - like the 'Turbo-Plus' aftermarket intercoolers for the turbo Senecas, except the latter aircraft uses NACA ducts versus an under-cowling scoop. As far as the gear doors go... well, you'll like them fully enclosed until a sequencing malfunction leaves them hanging, and you possibly stranded somewhere - at the worst possible time. It's actually quite a good mod that I'm glad someone took the time, trouble and money to STC. You don't just 'remove' the inboard doors, it actually has sheet metal formed that has to be riveted in place with circles cut out for the tire to retract into, cutting down on the already minimal drag. Those are now marketed by Mike Jones Aircraft in Murfreesboro, TN. I've chatted at length with the fellow that developed this mod, although we have not actually installed one ourselves just yet. We will if we stay in the Navajo business. Denali Air put them on theirs and they love 'em. Good Stuff!
Happy New Year! ~~ Mark