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