Which model to buy.
 

Not to ad to the nauseum, on turbo vs NA, but I'm still unable to make the call. I've read just about everything I can find on the subject from Mike Busch's treatise on turbos, to the information found here. I get the cost considerations (I think), and the operational challenges (I think), but not the mission requirements part.

In short, the mission will be 1-3 hour trips (and back) twice a month, and a few $300 burgers ($400 with engine reserves). The base is the NY tri-state area. Destinations are like Quebec, Winston-Salem, Maine--that sort of thing. So nothing a cowboy would refer to as mountainous (though one day I'd like to cross that stuff too--at least once). Steering me toward a turbo is the prospect of stranding anxious passengers far away on a Cumulus-filled Sunday afternoon (say 17k-footers) because I don't have a turbo. (still part 91, to be clear). I don't fancy the choice between stranding them and terrifying them. Then of course there's weather that you really need to climb out of. The turbo could rise above all of that (couldn't resist--sorry). With only a POH to go on, it looks to me like a 71 C-model full of friends isn't making any hasty climbs out of bumpy stuff or ice.

Should I buy a turbo for the occasional cumulus-soaked Sunday? I don't know--a lot of Sundays are that way in northeast summers, and I'm concerned those outings will become more occasional with each stranding/terror.

Thoughts?

Plenty of people fly NA over the rocks, and plenty of others fly turbos over the plains. The turbo gives you capabilities the NA doesn't, but also bills the NA doesn't. And they weigh something too.

This pilot's opinion: If flying above 10k feet regularly, a turbo is an extremely nice to have. If flying out of high DA airports, also extremely nice to have.

I think the concerns about climb performance to get over weather, or stranding passengers, are not the right ones. Why? Because if the weather is marginal without turbos, it will still be marginal with turbos. At 17k feet with passengers and fuel, even the turbo aircraft are not climbing more than ~600fpm without getting really hot. So climbing through 3000' of icing means 5 minutes -- long enough to build up a fair bit of ice, which in turn will make that climb even longer.

Bottom line: If you get the turbo, I doubt you'll regret it even if you rarely need it. But it will cost more to buy and maintain. If it were me, I'd buy it, but ... it isn't me, it's you :)

Dan

Turbocharging is nice to have especially when one engine quits on a hot humid day, particularly if there is weather/terrain below you that you don't want to descend into. Trade-off weight, more likelihood of needing a top overhaul, and overhaul costs of the turbo/waste gate/controller.

It's only money $$$$$$
The turbo will cost more $$$ all the way around.
Just like gas via diesel pickup truck

This happens a lot less than you think. Will the turbo get above the afternoon turbulence into drier, cooler air for a smooth ride? You betcha.

Can you safely navigate through the mid-afternoon crap down at 9000ft in an NA plane? Yes, but it's not as comfortable.

"Need" is a relative term.

Turbo in a 337 usually means a P337 and now we are talking about a very heavily loaded/equipped plane. The Riley Sky Rocket I look after has a measly 500lbs pay-load, so no-way you are filling it with friends !


On the other hand a nice NA 337 will have a payload closer to 900lbs, so you could indeed bring the buddies albeit, you're not going to FL200.

When you talk about "payload", I'm assuming that you're talking about what's left after the fuel weight. I assume, because the numbers I see put something like a 1400 useful on the P.

Regardless, I've been dissuaded by the local 337 A&P from getting into the P, in spite very appealing comfort. He put a number like 1.5-2x on the recurring costs (but I don't want to (re-)start those threads). So I'd be looking for that rare Turbo II, or putting up with hydraulic power-packs and doors that go like this <--[]-->.

To turbo or not to turbo, that is the question
 

I was a heli-chopter owner pilot first, and originally saw no valid reason to go over 1,000 ft. Nothing the see up there.

But when getting a 'thrasher years ago, original mission to/from WashDC/Boston, I experienced the anemic hot summer climb of a non-turbo above 9,000 ft with 3.5 people aboard up the east coast. One of my instructors could have been a linebacker, the other a skinny french guy.

So not sure, I got a turbo, and have had it for 25+ years (during which time, I must note, like Dorian Gray, I've not aged a day). It's a full RSTOL which has other advantages.

On hot summer days, it is really really really really nice to quickly pop up over the convective layer quickly with family, friends, kids, dog on board. Around Wash DC that's often 6-9k.

On a x country to OSH last year, below 9-10k it was hot and humid. Lots of near convection, bump bump bump.

We quickly popped up on top, dropped down for lunch in Port Clinton, popped up again. All nice an cozy, all the time thinking of the poor slobs stuck down below bouncing and sweating.

There was a line of WX between Clinton and OSH. Easily and quickly popped up briefly to 14k over the top, Piece of cake. Like skiing giant moguls at 200 mph.

Whole trip would've been a slog below 12k, or climbing to/from, coming and going.

That said, we have a beach house in NC. I often fly low along the shoreline, down the Potomac river, across the Chesapeake bay, wrap around NAS Oceana, along the NC beach, then climb UP (!) to pattern in Hatteras. (Re3member, a heli pilot. To us 1k ft is high).

When I do that, throttle back, music playing, turbos are just idling at lower power.

Things could be a lot worse...

Yep, figure 150 gals@ 900 lbs, so you're left with about 500.

I would agree with your A&P .

I thought the P models gross went up to 5100 lbs?

My T337D has a RSTOL increased gross takeoff of 4,700 lbs
About 3k empty, so about 1700 lbs payload.

Minus 128 gals x 6lbs/gal = 768 fuel, plus almost 1,000 lbs of people and stuff.

There was one trip to start the summer,
family of 4, (2 SMALL kids)
large afghan hound (skinny, but huge)
100 lbs of flowers,
two violins, a cello,
plus boxes of tiles to redo the kitchen
..AND a new kitchen sink.

I literally head everything in there INCLUDING the kitchen sink.
That was at gross.

D

4630, without modification

And what mod allows more ?

(When I researched this, I found nothing but an empty sales pitch …)

Other than the proprietary increase that Air Scan did the only increase I am aware of is Robertson STOL. This was an increase gross weight for take off but defaulted back to certified gross weight for landing. It's a lot more work and money to change the weight for landing than it is for take off. VG's on the Skymaster did not gain any GW like a lot of other twins benefit with. There are some early (pre 73) Turbo models that have R-STOL but very few later model Skymaster had the R-STOL. It's cost prohibited to install an R-STOL system today, even if Sierra would do it. The P models are heavy birds and will work pretty good for 2 adults and gear with long range fuel but for 4 adults the fuel load is going to be compromised.

We've had OUTRAGEOUS wx in the Great Lakes the past couple of weeks...afternoon CB and TCU popping up with tops over 40'000'

No turbo is helping you out there.

Ewww...no... Those are not the clouds I mean.