110716 building dh-2 replicas - falcondesign · building dh-2 replicas challenges, learnings and...
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Building DH-2Replicas
Challenges, Learnings and Accomplishments
Ernie Moreno, Gary McCormick, Paul Sieber,Mike Pongracz, Frank Koch, Bill Osborn, Bruce Rose
and a Community of Support
EAA chapter 292 project in Independence, Oregon
Inspired by previous Nieuport 11 project of a few years back
Nieuport project had 13 builders and 14 airplanes
DH2 project has 5 builders and 5 airplanes
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Why the DH-2
Simple to build(we are naïve)
Docile in flight(hopefully)
Unique
DH2 selected because few replicas exist
Open construction appears simple
Flight reports indicate is should be docile
“Not trying to build flying coffins”
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Assemblingthe Team
• Interest in building airplanes
• Diverse backgrounds
• Worked together on other projects
• Each person builds their own aircraft– Pay into common bank account as we go
• Community members also contributing
Each owner builds their own aircraft
Small team is easier to work with than large team
Small team generates better ideas than a single individual
Team members need to be able to work together
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Pictures, Drawings and PlansExtensive internet search
Located articles, books, pictures, drawingsNo plans found
CalculatedWeightBalancePowerSpeed
Creating plans as we go
No plans have been located
Limited drawings available on the web and in books
Very much a ‘design as you go’ project
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In the spirit of the originalModern materials and tools
Riveted aluminumstructure
Wooden ribs, landing gearand cabane struts
Construction Techniques
Built to look like an original airplane
Designed to perform like a modern airplane
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Aircraft Scale
Scaled down would be too smallThis will be a slow flying aircraft70% scale has 50% wing area80% scale has 65% wing area
1:1 scale is HUGE!
Scaled down aircraft often do not perform well
Full scale aircraft are HUGE
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Construction LocationSpace is tight in the hangar- projects expand to fill available space
28 foot wingspan(2 wings per plane)
10 foot tail span
9 feet tall
Fortunate to have access to large EAA hangar and well equiped shop
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Engine selection• Need about 100 hp• Radial would be wonderful
– Radials are expensive
• VW with PSRU will work and be affordable
Would like to have an original appearing engine
Cost and reliability dictate a more modern choice
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Propeller
• 8 feet in diameter• Wood• Slow spinning• Original was 4-blade
Will have custom made propellers
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Fuselage
• Square aluminum tube with rivets and gussets– Simple, light, affordable, strong
• Jigs to insure accuracy, repeatability
Modern construction techniques save weight and build time
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TailFeathers
• Aluminum tube with rivets and gussets• Tubing bent by hand
– With and without bending forms
• Jigs for assembly alignment
Tail weight is a major concern
Aluminum is the lightest choice
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Wings
• Modern airfoil (Clark Y)
• Plywood ribs• Aluminum wing spars
Looked at airfoils from more modern airplanes
Need ‘simple’ ribs; many are required
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Landing Gear• Motorcycle tires• Custom built wheels• Minimal brakes
We will be using landing strips rather than airfields
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Instruments• Just enough
– No more
Not much instrumentation required
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Flying
• Flight speeds of slow and slower– Best in warm weather and calm winds– Glide ratio probably less than 4:1
• Experienced test pilot for first flights– Public will be invited AFTER successful first flights
Great for calm weather flying
Not an all-weather plane
Test flying is an important part of the project
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Partial Bill of Materials (5 planes)• 25 – wing center section ribs
• 40 – wing tip ribs
• 65 – wing short ribs
• 70 – wing tail ribs
• 140 – wing long ribs
• 230 – wing nose ribs
• 480’ – wing spar tubing
• 570’ – square fuselage tubing
• 2000 – 3/32” aluminum rivets
• 2800’ (1/2 mile) – wing rib cap strips
• 5500 – 1/8” stainless steel rivets
LOTS of parts required to build 5 biplanes
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283Fuel and oil
180Pilot
80Military load
D.H.2 Useful Load
Our replicas will be 75% of the weight of the originals
Weight and balance are critical design parameters
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49610Wing Loading (lb/sq.ft)
10121416Power Loading (lb/hp)
355548Stall Speed (MPH)
7096123Cruise Speed (MPH)
8013593162Max Speed (MPH)
300704543489Useful Load (lbs)
7001,93110041111Empty Weight (lbs)
10002,63515471600Max Weight (lbs)
100220100/110100Engine Horsepower
VolkswagenCont. R-670-5Gnome Monosoupape, Le RhoneCont. O-200Engine Type
25.224.825.224.8Length (ft)
249298249160Wing Area (sq.ft)
9.59.79.58.5Height (ft)
28.332.228.333.3Wingspan (ft)
8.288.25.8Propeller Diameter (ft)
2012193419151958Year Introduced
D.H.2 replica
StearmanPT-17
D.H.2original
Cessna 150
Comparisons to more common aircraft