Cessna 170

Note on engine designations: The Continental C-145-2 and O-300-A are closely related engines. The O-300 designation reflects Continental's adoption of the standardized military naming convention; the core engine is the same 6-cylinder, 145 HP horizontally-opposed design. TBO for all variants is 1,800 hours.

The 170B's book cruise of 104 KTAS at 65-70% power is honest and achievable in real-world conditions, burning 7-8 GPH at altitudes below 8,000 feet. At 75% power, expect 110-115 KTAS while burning 9.6 GPH. The aircraft does not have a POH in the modern sense; Cessna issued an Owner's Manual (unapproved) and a one-page AFM for the performance data required by CAR 3 at the time of certification.

The 170B's standout performance feature is its Fowler-type flap system. These slotted, rearward-traveling flaps, borrowed from the military L-19 Bird Dog, provide dramatically better short-field numbers than the 170A's plain flaps. The 170B can put a competent pilot into strips that would give a stock 172 serious pause. Ground roll at sea level on a standard day is 728 feet for takeoff and 460 feet for landing, with 40-degree flaps providing steep, draggy approaches ideal for short strips with obstacles.

The 170A, by contrast, has plain flaps with 50 degrees of deflection that produce more drag than lift at high settings, making the airplane sink rapidly on approach without meaningful lift benefit. This is a critical distinction for backcountry work.

Real-world climb performance with the 145 HP Continental is adequate but not sprightly. At gross weight on a warm day at elevation, expect 400-500 fpm. Density altitude management matters in this airplane. The relatively low horsepower-to-weight ratio (approximately 15 lbs/hp) means departing high-altitude strips on hot days requires careful planning.

Best glide is approximately 65 KIAS (75 mph) with a tested glide ratio of roughly 7:1 clean with the prop windmilling.

The 170B's 980-lb useful load is generous for a 145 HP four-seater, but real-world loading requires thought.

Scenario 1: Full Fuel + 2 Occupants (Touring / Backcountry)

This is the sweet spot: two people, full fuel, and enough margin for camping gear or a third lighter passenger. The 170 is a genuine two-plus-two in this configuration.

Scenario 2: Four Occupants (Full Seats)

With four standard adults, you can carry nearly full fuel. However, with four large adults (200 lbs each), fuel must be reduced. This is not a four-large-adult airplane at full fuel, but it handles a typical family (two adults, two children) with full tanks comfortably.

Scenario 3: Backcountry Mission (Modified 170B with 180 HP)

This configuration leaves comfortable margin below gross weight, which is exactly what you want when operating from unimproved strips at elevation. The 180 HP conversion does not change the gross weight (still 2,200 lbs per most STCs), but it transforms the airplane's ability to use that weight at high density altitudes.

The 170 vs. the 172: Understanding the Succession

When Cessna replaced the 170 with the 172 in 1956, the primary change was swapping conventional gear for tricycle gear. The early 172s shared the same Continental O-300 engine, the same basic airframe, and nearly identical performance. Cessna made the switch because nosewheel aircraft were dramatically easier for new pilots to land, and the post-war flying boom demanded accessible aircraft.

What the 172 gained in accessibility, it lost in backcountry capability. The nosewheel is vulnerable on rough surfaces, the prop is closer to the ground, and the aircraft sits with less angle of attack. The 170's tailwheel configuration gives it inherent advantages on grass, gravel, and unimproved strips. The 172 also adopted a straight tailfin (the 170 has a distinctive rounded fin), and later 172s moved to Lycoming engines, diverging the lineage further.

Today, a stock 170B and a stock early 172 are remarkably similar airplanes in the air. The difference is on the ground, and for many pilots, that difference defines the experience.

Flight Training (4/10): Not a primary trainer, but a reasonable tailwheel transition platform for pilots moving beyond the 150/152. Four seats allow an instructor plus student with room for a safety pilot or observer. Insurance for training use is expensive. Better tailwheel trainers exist for primary instruction (Citabria, Decathlon, Super Cub).

Backcountry (7/10): This is where the 170B truly shines relative to expectations. The combination of tailwheel gear, effective Fowler flaps, high wing for ground clearance and visibility, and 980 lbs useful load makes it a legitimate backcountry four-seater. With big tires (26-31 inch Bushwheels), a STOL kit, and an engine upgrade to 180 HP, a modified 170B approaches 180 Skywagon capability at a fraction of the cost. Stock, it scores lower than a purpose-built bush plane, but modified examples are serious backcountry machines. Docked points for the 145 HP engine being marginal at high density altitudes and gross weight.

Business Travel (3/10): Limited by modest cruise speed (104 KTAS), lack of modern avionics in most examples, and the tailwheel configuration that most FBOs and rental car agencies find unfamiliar. Not the mission this airplane was built for.

Aerobatics (1/10): Not approved for aerobatic flight in Normal Category. Utility Category limits (2 seats, reduced gross weight) allow steep turns and stalls but not aerobatics.

Cross-Country (5/10): Capable but not ideal. With 42 gallons and 7-8 GPH burn at economy cruise, range of 410 nm with reserves is reasonable for weekend trips. The rear seat is comfortable enough for two adults on shorter legs. Drawbacks: modest cruise speed, wind noise, and the fatigue factor of a 1950s airframe on longer flights. A well-equipped 170B with a modern GPS makes a pleasant 200-300 nm touring airplane.

Cargo Hauling (4/10): The 980-lb useful load is good on paper, but full fuel (252 lbs) and two front-seat occupants leave limited cargo capacity. The rear seat folds for bulky items. Not a hauler, but adequate for camping gear and supplies for a backcountry trip.

Local Fun Flying (8/10): This is the 170's sweet spot alongside backcountry. A beautiful Saturday morning, a grass strip, the satisfying rumble of a Continental six-cylinder, and honest tailwheel handling make this airplane a pure joy for recreational flying. The high wing provides excellent sightseeing visibility. Landing a 170 well on a grass strip is one of GA's simple pleasures.

Surveying (5/10): High wing provides decent downward visibility, and the relatively slow speed is actually an advantage. However, no modern examples come with survey-specific modifications, and the tailwheel gear complicates operations at unfamiliar paved airports.

Most 170s still flying have panel configurations spanning seven decades of avionics evolution.

Budget / Minimalist ($0-$5,000 upgrade): Many 170s retain original or near-original panels with analog six-pack, a single NAV/COM, and perhaps a handheld GPS mounted on the yoke. For VFR backcountry and local flying, this is adequate. A panel-mounted Garmin GPS (used GNS 430W or GTN 625) is the single most impactful upgrade.

Mid-Range ($10,000-$25,000): A Garmin GNS 430W or GTN 650Xi paired with a modern transponder (GTX 345 for ADS-B In/Out) transforms the airplane's cross-country and IFR capability. Many owners add an electronic attitude indicator (GI 275 or uAvionix AV-30) as a backup or primary.

High-End ($25,000-$50,000+): Full glass conversions are rare but not unheard of, typically featuring dual GI 275s, a GTN 650Xi or 750Xi, and an audio panel upgrade. At this investment level, owners are typically building a "forever airplane" with a concurrent engine upgrade and airframe restoration.

The 170's panel space is adequate but not generous. The steam gauge panel accommodates standard 3-1/8" instruments, and most modern retrofit displays fit without major panel rework.

The 170 has a rich STC ecosystem, reflecting its popularity as a platform for customization.

Engine Upgrades

The 180 HP Lycoming O-360 conversion is the gold standard upgrade. It improves takeoff roll by 20-25%, climb rate by 200+ fpm, and provides meaningful margin at high density altitudes. It also moves the airplane to a Lycoming parts and overhaul ecosystem that many owners and mechanics prefer.

STOL Modifications

Bush / Backcountry Modifications

A fully built-out backcountry 170B with 180 HP conversion, STOL kit, 29" Bushwheels, and heavy-duty gear can easily represent $25,000-$40,000 in modifications on top of the airframe purchase price.

Parts Availability — Good

The Cessna 170 shares substantial parts commonality with the early 172, 180, and other Cessna singles from the same era. This is a significant advantage:

• Airframe parts: Wing skins, ribs, control surfaces, fuselage skins, and hardware are available from Cessna (Textron), Univair, and Wag-Aero. Supply is adequate for routine maintenance; exotic or model-specific parts occasionally require patience.
• Engine parts: Continental O-300 parts remain available through Continental (now Continental Aerospace Technologies), Univair, and the used/surplus market. The engine's long production run and use across multiple Cessna models helps.
• Landing gear: Spring gear legs, tailwheel assemblies, brake components, and tires are readily available.
• Fabric (170 only): Ceconite, Poly-Fiber, and other STC'd covering systems are readily available. Fabric-wing 170 maintenance is not a parts problem; it is a labor and skill problem.

Mechanic Familiarity — Common

Any A&P familiar with Cessna singles can work on a 170. The airframe is simple and well-documented. The Continental O-300/C-145 engine is straightforward. However, tailwheel-specific rigging (tailwheel springs, cables, steerable vs. free-swiveling configurations) benefits from a mechanic experienced with conventional-gear Cessnas.

Annual Cost Range

Expensive Maintenance Items

• Engine overhaul: $37,500–$52,500 for O-300. $45,000-$40,000 for Lycoming O-360 conversion engines.
• Fabric re-cover (170 only): $15,000-$45,000 for both wings.
• Prop overhaul: $1,500-$2,500 for fixed-pitch metal prop.
• Exhaust system replacement: $2,000-$4,000 for a complete exhaust.
• Magneto overhaul/replacement: $500-$1,200 each.

The Cessna 170 market has been appreciating steadily, driven by the convergence of two buyer pools: classic aircraft collectors and backcountry enthusiasts. The 170B commands the strongest prices, with the 170A following and the fabric-wing 170 trailing.

Price Tiers (2025-2026)

Key Value Drivers

• Engine time: A freshly overhauled O-300 or Lycoming O-360 conversion adds $15,000-$25,000 to value versus a run-out engine.
• 180 HP conversion: The single largest value-add STC. Adds $20,000-$35,000 to resale value.
• Avionics: A GNS 430W or GTN 650 with ADS-B adds $10,000-$20,000.
• Total time: Less impactful than engine time, but very high total-time airframes (5,000+ hours) warrant more thorough structural inspection.
• Corrosion history: Any history of significant corrosion repair substantially discounts value.
• Fabric-wing (170 only): Commands lower prices due to higher maintenance burden and re-cover cost, though mint examples have their own collector appeal.

Values are trending upward approximately 5-8% per year as supply naturally contracts (attrition) while demand from the backcountry community grows. The 170 is increasingly seen as a "poor man's 180" with genuine capability when properly modified.

Airworthiness Directives

The Cessna 170 has accumulated a significant AD list over its 70+ year service life. Key categories include:

Structural ADs:

• Wing spar inspection ADs — Recurring inspections of the wing spar attach fittings. Critical on all models. Ensure compliance is current and documented.
• Seat rail AD (AD 2011-10-09) — Applies broadly to Cessna single-engine aircraft including the 170 series. Inspection/replacement of seat rail and roller assemblies to prevent seat slippage on takeoff. One of the most important ADs across the Cessna fleet.
• Flap actuator inspection — 170B Fowler flap actuating mechanisms require periodic inspection.

Fabric-Wing 170 Specific:

• Early Model 170 (1948-1949) fabric wings require careful attention. Fabric condition, rib stitching, and internal corrosion are primary concerns. A fabric-wing 170 is not necessarily a problem airplane, but the annual inspection must include thorough fabric testing (punch test / Maule tester) and internal inspection of wing structure. Re-covering runs $8,000-$15,000 per wing.

Engine ADs:

• Various Continental C-145/O-300 ADs covering crankshaft inspection, oil pump drive, and accessory case. Most are one-time compliance or addressed at overhaul.

Common Pre-Buy Red Flags

• Corrosion — 70+ year old airframes demand thorough corrosion inspection, especially in the belly, wing roots, and around fuel tank bays.
• Landing gear attach points — Tailwheel aircraft see higher gear loads. Inspect spring gear legs, tailwheel mount, and associated fuselage structure.
• Exhaust system — Continental six-cylinder exhaust systems are prone to cracking. Inspect thoroughly with a mirror and bright light; cracks can be hidden.
• Windshield crazing — Original or aged plexiglass develops fine crazing that worsens visibility in sun glare.
• Control cable wear — Original pulleys and cables may show excessive wear after decades. Complete re-rigging is not uncommon in restorations.
• Fuel tank integrity — Bladder tanks deteriorate; wet-wing tanks can develop leaks at seams.

Insurance for the Cessna 170 falls into the tailwheel fixed-gear category, which carries higher premiums than equivalent nosewheel aircraft due to the higher ground-loop incident rate inherent to conventional gear.

Typical Premiums (2025-2026)

Qualified pilot minimums (typical underwriting): Private certificate, 300+ total hours, 25+ tailwheel hours, 10+ hours in make/model. Some underwriters require a formal tailwheel checkout with an instructor endorsed on the policy.

Underwriting notes:

• Tailwheel time is the dominant factor. A 1,000-hour pilot with 10 tailwheel hours will pay more than a 500-hour pilot with 100 tailwheel hours.
• Hull values have risen faster than underwriters have adjusted, so ensure your agreed hull value reflects current market replacement cost, not what you paid years ago.
• Backcountry use endorsements (off-airport operations) may carry additional premium or exclusions depending on the carrier.
• Some carriers restrict coverage for student pilots or renters operating the aircraft.

See GA Insurance Underwriting for broader context on GA insurance markets.