I am a first time T.C. buyer looking for a '66 or later but not a C/R. I read somewhere that circuit breaker panels were relocated in later years to a more "modern" location. Where can I find documented configuration differences through the years of production? What are the "important" differences?

I read that the 200 hp Miller climbs better but at most altitudes goes the same cruise speed on more fuel as the 160's ? True?

What effective sound proofing exists for TC'S? Who could I discuss these and other questions with on the phone?

Bob. 312.401.8080

bob.rubens 757@gmail.com

Bob,

Welcome to almost Twin Comanche ownership.

I see by your area code, you are in the Chicago area somewhere. Learned to fly at Elgin airport before it became a Venture parking lot in the early 1970s.

Probably the shortest answer to your question on configuration is that since all Twins are nearly 40 or more years old now, owners have made a lot of changes and even though my 1970 has most of the circuit breakers on the panel below the co-pilot yoke, that doesn't mean that older models that had them in a different location couldn't have updated their panel to have the same circuit breaker location. yeah, I know that doesn't answer your question but does let you know that when someone does, it will not be cast in concrete. Newer TC have 6 windows and access to the rear which I prefer.

There are some really knowledgeable twin owners in the north central Tribe so attending a fly-in will help but frankly a lot of the questions just get answered here.

When you get your magazine or read it here online, you'll notice Heritage Aero in Rockford is a really good Comanche shop. Whenever you settle on a plane, be sure to get a pre-buy by a Comanche knowledgeable mechanic and regardless of your hours, the CPPP course comes highly recommended. http://www.comancheflyer.com/NS/hold/h1/cf_ppp.htm

Rather than stress over sound proofing - did put in some new stuff with the new interior but it weighed more so I used judicious placement in the side panels above the floor - we got noise cancelling headsets. Although, I ditched mine for a less head-clamping spongy ear insert approach with Mach 1 by Lightspeed and it works well for me.

Hope this helps a bit.

The C model is the only factory model, non C/R with the revised location of the breaker panel, as well as the rocker switches and the standard T panel layout, a thicker stabilator, and factory installed alternators. However, many other aircraft have been modded to similar standards due to complete panel replacement upgrades and rewiring to include relocation of the breakers above the floor, or in the panel (each aircraft these days is truly a one of a kind custom job. There really is no such thing as a stock aircraft at this point). 1969 is the year of the C model, with 1970 seeing the C/R configuration as factory standard, and the aircraft redesignated as a PA-39 (really as simple as a C/R C model, no real differences other than the LIO engine).

Other major model year characteristics are :
63-65 - 4 window cabin, rear bench seat, dual fork main gear legs, Southwind heater, rear battery, 200 lb separate baggage area, starboard bagage door, Turbo available starting in 64.

65-68 (B model)- 6 window cabin, rear bucket seats, Janitrol heater, Single fork MLG legs, 250 lbs baggage limit with provisions for 2 "family seats" in lieu of baggage (making it a marginally 6 place aircraft), Port baggage door that doubles as emergency exit, forward mounted battery.

69 (C model)- Standard T panel layout, rocker switches, rams horn yokes, breakers on panel, thicker stabilator, dual alternator charging system

70-72 PA-39- Counter Rotating C model

As Zach notes, they are all different at this point. Many older twins have had a Ron and John's panel (or equivalent) put in with the breakers moved up to the co-pilot's panel. There is at least one with a custom switch/breaker panel on the left side wall. Mine has the "breakers in a box" in the floor. It's been a minor annoyance, but not enough to make me spring to move them up. To me the more important thing on the electron front would be, has the electrical system been modernized? After 50 years insulation cracks, things get brittle, breakers fail. Good things to look for are copper wiring upgrades, Bogert battery boxes, replaced breakers and new wiring harnesses for radios and the landing gear. I also think PlanePower alternators are a plus, but some like the older systems.

My experience with Miller twins is limited to some passenger time, but my observation is that you are right. They do climb better, but are not much faster. If fast cruise is an objective then a turbo twin above 12,000 feet will get it done too. I have a turbo and like it, but I also have mountains with permanent glaciers on them right out my window resulting in MEAs of 10,000 and up on most of my frequent routes. If I lived in Chicago, I think I'd go normally aspirated, FWIW.

Jay