Christen Eagle II

The Christen Eagle II is a two-seat, tandem aerobatic biplane designed by Frank Christensen and introduced at EAA Oshkosh in 1977. Christensen — an aerobatic pilot who managed the 1972 World Aerobatic Champion U.S. team — set out to build an airplane that would fly as well as the aviat-pitts-s1-s2 but offer more comfort, better visibility, and enough cross-country manners to actually tour in. The Eagle II was conceived as the Pitts' more refined competitor.

Beyond the airframe itself, the Eagle II changed the face of homebuilding. Christensen's kit was the most comprehensive, well-documented, and revolutionary build system produced up to that point — 26 sub-kits shipped sequentially, with detailed manuals, pre-welded assemblies, and photographic step-by-step instructions. It opened aircraft building to people who had never before considered it possible. The Eagle's manual set a new standard that every modern kit manufacturer has since emulated.

The Eagle II features a small single-bay, equal-span staggered biplane with streamlined flying and landing wires, an I-strut forming a box truss, symmetrical airfoils, tandem seating under a large bubble canopy, and a fixed tailwheel undercarriage. Power is a Lycoming AEIO-360-A1D rated at 200HP, typically swinging a constant-speed Hartzell or MT composite propeller.

The Eagles Aerobatic Team (Charlie Hillard, Tom Poberezny, Gene Soucy) famously chose the Christen Eagle in 1979 to replace the Pitts Specials of their "Red Devils" act, flying Eagles in formation airshows until 1995.

Christen Industries sold nearly 500 kits by 1982. More than 350 completed Eagle IIs had flown by the early 2000s, with over 320 in the United States. Aviat Aircraft in Afton, Wyoming acquired rights from Christen Industries in the 1990s and continued marketing the kit as the "Aviat Eagle II" alongside its certified aviat-pitts-s1-s2 line. As of 2025, a newly formed Christen Industries has renewed production under the original Christen Eagle name.

The Eagle II is fundamentally a single-configuration aircraft — the kit has remained largely unchanged since 1977. Variation comes from builder choices rather than distinct factory models.

Builder-selected options that materially affect individual aircraft:

• Propeller: Hartzell 2-blade constant speed (traditional) vs MT 3-blade composite (lighter, smoother, preferred in modern builds)
• Smoke system: Oil injection smoke system — nearly universal on Eagles used for airshow or formation work
• Canopy tint and panel fit: Significant variation between builders
• Panel complexity: From bare-bones VFR to full EFIS glass with GPS

The Eagle II cruises at approximately 165 mph (143 KTAS) on 9 GPH — noticeably faster and more fuel-efficient than a comparable 200HP aviat-pitts-s1-s2 S-1T, and with a lower fuel burn thanks to the cleaner aerodynamic package. The 380 nm range on 25 gallons usable makes the Eagle genuinely viable for touring — something the Pitts with its 277 nm range cannot honestly claim.

Climb performance is strong at 2,100 FPM solo — not Pitts-level vertical (the S-2C does 2,900 FPM with 260HP) but more than enough for a full aerobatic sequence to altitude. Service ceiling is 17,000 feet. The aircraft will maintain vertical lines until airspeed bleeds to low values, enabling all the standard aerobatic vertical figures.

Roll rate is approximately 187 degrees/second, with some sources citing up to 204 deg/sec — faster than a Pitts S-2 but slower than a modern monoplane extra-300. The symmetrical airfoils provide identical performance inverted and upright.

G-limits are typically cited as +7/-5 G operational, with structural ultimate limits reported as high as +9/-6 G. These are builder- and inspection-dependent on an experimental aircraft and should always be verified against the specific aircraft's Operating Limitations.

Stall speed is 58 mph (50 KIAS), and like the Pitts, there are no flaps — stall speed clean equals stall speed "dirty." Approach speeds are 80-90 mph. Forward visibility on final is better than a Pitts due to the different seating position and fuselage geometry, but the Eagle still demands tailwheel proficiency and precise speed control.

Compared to a Pitts, pilots consistently describe the Eagle as "more forgiving on landing" and "easier to tour in," though still a demanding tailwheel aircraft. The Eagle's reputation is for aerobatic capability at near-Pitts level with meaningfully better touring comfort — exactly the mission Christensen set out to achieve.

Eagle II (AEIO-360-A1D, 200HP, 25 gal usable):

With a 553 lb useful load, the Eagle II is meaningfully more capable than a aviat-pitts-s1-s2 S-2B (475 lb useful load) in the payload department. Two 180-lb pilots with full fuel leaves 43 lbs for minimal soft-bag baggage — enough for a weekend trip. Two 200-lb pilots still fit with fuel reduced to 18 gallons, giving ~270 nm range — a genuine touring envelope that the Pitts cannot match.

Solo aerobatic missions with full fuel leave substantial weight margin for smoke oil (typically 5-8 gallons / 35-55 lbs of aerobatic oil). This is the Eagle's sweet spot: a committed 1.5-2 hour aerobatic session with generous reserves.

The Eagle II delivers on Frank Christensen's original design brief — an aerobatic biplane that can also tour. It doesn't quite match the Pitts in unlimited competition or the extra-300 in raw performance, but for a pilot who wants one airplane that can do aerobatics on Saturday morning and a 300 nm cross-country Saturday afternoon, the Eagle II is arguably without peer.

• Flight Training (3): Not a primary trainer. Used for aerobatic instruction for experienced tailwheel pilots. Somewhat more forgiving than a aviat-pitts-s1-s2 but still demanding.
• Backcountry (1): No. Fragile biplane, minimal prop clearance, no baggage, no soft-field capability.
• Business Travel (2): Two tandem seats, no real baggage area, weather-limited VFR operation. The 380 nm range is workable for short hops but the aircraft is fundamentally a toy.
• Aerobatics (9): Outstanding. +7/-5G operational limits, ~187 deg/sec roll rate, symmetrical airfoils, inverted fuel and oil systems standard on AEIO engine. The Eagle competes in IAC Sportsman, Intermediate, and Advanced categories effectively. At the Unlimited level it gives up ground to the aviat-pitts-s1-s2 S-1 and modern monoplanes like the extra-300, but for 95% of aerobatic pilots it offers essentially everything they need. Not scored 10 only because the 200HP class cannot match the 260HP Pitts or the 300HP Extra in unlimited vertical performance.
• Cross-Country (4): Meaningfully better than a Pitts. The 143 KTAS cruise on 9 GPH with 380 nm range is a genuine touring envelope. The Eagle was specifically designed with this in mind. Limitations remain: VFR-only in practice, no baggage, tandem cockpit, tailwheel fatigue on long days.
• Cargo Hauling (1): No.
• Local Fun Flying (9): This is what the Eagle was built for. A stunning biplane profile, strong aerobatic capability, genuine dual-cockpit fun with a passenger, and enough range to make the $100 hamburger easy. For a pilot who wants "Pitts-level aerobatics with touring ability" the Eagle is arguably the best answer ever produced.
• Surveying (1): No.

See aerobatics for mission scoring methodology.

The Eagle II is experimental, so builders have complete freedom in panel design.

• Traditional build (1980s-1990s): Minimal VFR steam gauges — airspeed, altimeter, VSI, tachometer, manifold pressure, oil/CHT/EGT, slip ball, G-meter, handheld GPS, single comm radio. Many Eagles flew for decades with nothing more.
• Modern build: Dynon SkyView HDX or Garmin G3X Touch EFIS, Garmin GTN 650/750 GPS/nav, Garmin GTR 200 comm, Trig TT22 transponder with ADS-B Out. Lightweight and vastly more capable than what the Pitts S-2C offers as certified equipment.
• Aerobatic instrumentation: Dedicated G-meter (recording min/max), Alpha Systems AOA, smoke system switch, and inverted-system annunciators.
• IFR: Technically possible with experimental IFR GPS and two-axis autopilot, but essentially nobody does this — the Eagle's mission and cockpit environment don't suit IFR operation.

See avionics-pricing for experimental avionics costs. A modern glass Eagle panel runs $15,000-$25,000 installed; a traditional steam gauge panel runs $3,000-$6,000.

As an experimental aircraft the Eagle II is not subject to the FAA STC system — builders and owners may modify it freely within Operating Limitations.

Common modifications:

• MT 3-blade composite propeller: Replaces the original Hartzell 2-blade. Lighter, smoother, better ground clearance, and reduces vibration-induced airframe fatigue. $8,000-$12,000 installed.
• Smoke system: Oil injection smoke with cockpit-controlled pump. $2,500-$5,000 installed.
• Inverted fuel and oil systems: Standard with AEIO-360 engine — the "I" in AEIO denotes inverted oil. Required for competition aerobatics.
• Engine upgrade to AEIO-360 with 210HP or AEIO-390: Some owners have upgraded to higher-output engines for improved vertical performance.
• LED nav/strobe/landing lights: Weight reduction and reliability.
• Lightweight starters and batteries: Every pound matters on an aerobatic aircraft.
• Composite cowling and fairings: Weight reduction and cleaner aerodynamics.
• Canopy tint upgrades: Reduced cockpit heat and glare.

• Annual condition inspection: $1,500-$3,000. Experimental aircraft require an annual condition inspection by an A&P (or the builder if they hold a Repairman Certificate). Less onerous than a certified annual but still involves thorough structural and fabric inspection.
• Engine overhaul: $30,000 for AEIO-360 at 1,600-2,000 hour TBO (shorter in aerobatic use).
• Fabric maintenance: Re-cover every 15-25 years depending on storage and exposure. $15,000-$30,000 for a full recover. Spot repairs are routine.
• Rigging: Periodic flying wire tension checks and re-rigging. Requires specialist knowledge — not every A&P can rig an Eagle correctly.
• Parts availability: Good. Aviat Aircraft continues to support the Eagle kit line, and the revived Christen Industries (2025) is supplying new parts. Most wear items (tailwheel, brakes, engine accessories) use common Lycoming / GA components available from Aircraft Spruce and similar suppliers.
• Mechanic familiarity: Specialist. Biplane rigging and fabric work require specific expertise. Owners typically develop relationships with a small number of known Eagle-competent shops or maintain the aircraft themselves.
• Annual all-in cost: $12,000-$18,000 for moderate use (50-100 hours/year).
• Operating cost: $90-$130/hour all-in.

See maintenance-ecosystem for broader context on specialist aerobatic aircraft maintenance.

Per valuation-methodology:

• Project or rough condition: $40,000-$60,000. Needs fabric, engine work, or major restoration.
• Flyable mid-condition: $60,000-$95,000. Solid airframe, mid-time engine, basic panel. The typical Eagle.
• Well-equipped, low-time: $95,000-$130,000. Fresh engine, glass panel, MT prop, smoke system, quality paint and interior.
• Showpiece or recent restoration: $130,000-$150,000+. April 2025 restorations have listed in the $110,000-$120,000 range; exceptional examples push higher.

Value drivers:

• Engine time since overhaul: $30,000 overhaul cost is the biggest single variable. Fresh engines add $20,000-$25,000 to value.
• Fabric condition: Fabric age and condition directly impacts value. Fabric with 10+ years of outdoor exposure materially reduces value.
• Builder reputation: Eagles built by well-known, meticulous builders command premiums. Unknown builders or first-time homebuilders discount the value.
• Airframe hours and aerobatic intensity: Aerobatic hours stress the airframe; competition-use Eagles have more fatigue than local-fun Eagles.
• Propeller: MT composite prop adds $5,000-$8,000 over the original Hartzell.
• Panel modernity: Glass panel adds $10,000-$15,000 over steam gauges.
• Smoke system: Adds $2,000-$4,000.

Compared to a aviat-pitts-s1-s2 S-2B (260HP, certified), the Eagle II typically trades at a $20,000-$50,000 discount for equivalent condition — reflecting its experimental status, lower horsepower, and smaller market.

Experimental aircraft are not subject to Airworthiness Directives the same way certified aircraft are. However, Lycoming AEIO-360 engine ADs apply, and the FAA issues Special Airworthiness Information Bulletins (SAIBs) for experimental aircraft.

Engine (Lycoming AEIO-360) ADs:

• Crankshaft AD (applies to various Lycoming models; verify by serial number)
• Oil pump drive gear inspections
• Fuel injection servo inspections

Common airframe problems:

• Wing wire rigging: The flying and landing wires require periodic tension checks and re-rigging. Improper rigging causes handling quirks and accelerated airframe fatigue. Specialist knowledge required.
• Fabric condition: The wings and fuselage are fabric-covered. Sun damage, tears, and fabric deterioration are the #1 long-term maintenance issue. Full recover runs $15,000-$30,000.
• Canopy hinges and latches: Bubble canopy hardware wears and cracks. Replacement canopies are available but expensive.
• Landing accidents: Like the Pitts, the Eagle's short-coupled tailwheel design and limited forward visibility make ground loops the most common accident mode.
• Builder quality variance: The Eagle's exceptional kit reduced builder variance compared to other homebuilts, but Eagles built by inexperienced or rushed builders still exhibit weight, rigging, and workmanship issues. A thorough pre-buy by an A&P familiar with Eagles is essential.
• Engine fatigue from aerobatics: Aerobatic operations accelerate wear. TBO is nominally 2,000 hours but practical overhaul intervals for heavily-used aerobatic Eagles often fall to 1,400-1,600 hours.
• Tailwheel assembly: Standard wear item, frequent maintenance required.

Per insurance-underwriting:

• Hull insurance: $3,000-$5,000/year. Experimental aerobatic biplane category. Premiums are similar to a Pitts, reflecting the shared risk profile (tailwheel landing accidents, aerobatic ops).
• Liability: $700-$1,400/year.
• Pilot minimums: Tailwheel endorsement required. Most underwriters require 25+ hours dual in type or documented aerobatic training before solo coverage. Low-time pilots face either high premiums or outright declination.
• Aerobatic coverage: Must be specifically requested. Standard policies exclude aerobatic operation. Aerobatic hull coverage typically costs 25-40% more than equivalent non-aerobatic coverage.
• Experimental surcharge: Some insurers apply a 10-20% surcharge for experimental/homebuilt aircraft compared to certified equivalents; others treat the Eagle as a well-known quantity and don't penalize it.
• Formation and airshow coverage: Requires a separate endorsement or policy.