This is the most recent post in my FS/Trade thread in the For Sale section. I thought I would move it here since it no longer involves that topic exactly. I ended up with a P337.
Quote:
Ken,
Beautiful bird. Congratulations! I am curious as you have owned both seneca and 337 how you would compare them. Similar vmc and engines. Just wondering what tipped the scales for you. I will need to upgrade at some point, growing fam of 5. Any insights appreciated.
Excellent question. While the Seneca does have a low Vmc, the P337 does not have one at all. It does have a blue line of course, best single engine rate of climb.
I owned a Seneca III and this is my second P337. The engines are both variants of Continental TSIO-360. -KB at 220 HP in the Seneca III, 1800 TBO and -CB at 225 HP in the P337, at 1,400 TBO. All three had air conditioning. The Seneca was Piper original, the first P337 had Horton and the current one has Keith. Keith is the best air conditioning, followed by Horton followed by Piper, in my opinion.
The Seneca did not have automatic waste gates nor intercoolers. Both can be added and I would suggest doing so. Due to this, the Seneca was probably the most complex airplane to fly that I have owned. The P337s had automatic waste gates from the factory and both of mine had intercoolers too.
The Seneca and P337s all ran well LOP without GAMIs although the Seneca was a bit more challenging to balance at higher power settings. As long as you run these engines properly, they live long and happy lives with minimal top end work needed during a TBO cycle. That's no greater than 65% power in cruise. I chose to run 65% power LOP. Run 75% power = buy cylinders.
Since it wasn't pressurized I flew the Seneca between 8,000 and 12,000 ft normally. There is benefit of the turbos at the higher altitudes, and of course in high dentistry altitude takeoffs so turbos were still a benefit. I flew the P337 often at 16,500 & 17,500 ft just because it is pressurized.
As many have said and I agree, "pressurization is a game changer."
For me, today, the P337 is a better choice, although the Seneca could work. For you, I think just the opposite. The Seneca is a better choice for a family of five. As you know the Seneca is a 6-7 seat airplane with a huge back door for passenger entry and club seating. It is also 7" wider than the P337. The useful load was greater in the Seneca and at least for the III, zero fuel weight isn't a huge concern.
The P337 is at most a five seat airplane. Since there is no second "emergency" exit it cannot be certified as a six seat airplane (normally aspirated and turbo models are six seat). Even though a P337 can be configured with five seats, the fifth seat removes half of the baggage space. The only baggage area in the P337 is behind the second row of seats. Configured as a four place, the baggage area is adequate in a P337 but a Seneca has a baggage area behind the third row of seats in addition to a large nose baggage area.
The Seneca III (worth the extra purchase price over the II) purchase price was 50% more than my current P337 and almost three times what I paid for my first P337. I bought the Seneca 15 years ago so consider that time difference too. Operating expenses are higher in the P337 simply because insurance is higher due it being pressurized. Fuel flow, maintenance, hangar and database updates are similar between airplanes. Both airplanes are similar in cruise speed but the edge goes to the P337. Not enough to make a difference.
I fly solo 95% of the time so the smallest pressurized twin made is right for me. I never have more than three passengers so I have mine insured as a four place airplane with sufficient baggage space. For you, with a family of five and needing baggage space and seats, the Seneca is my recommendation.
