Small two to four place twin engine aircraft with each engine having up to 115 hp (Rotax 914) power which is optimized for high altitude and long range flight.

Concept requirements 60 hp per engine model aka letter to the Santa Claus (HKS700E)

 (Please NOTE: Calculations proved that twin with two HKS700E engines is too underpowered in single engine situation, therefore this alternative is not realistic, at least it is not going to meet this performance criteria set above, this requirements matrix is subject to drastic change)

Concept requirements 100+ hp per engine model

Possible ways to achieve the goal

• high aspect ratio wing
• low frontal area
• low drag fuselage
• low drag wing profiles
• high Clmax despite of low Re (sophisticate high lift devices)
• retractable landing gear
• ability to fly at high altitude (high speed in TAS for given low power)
• negative sweep in wing
• zero degrees twist in wing
• best compromise trapezoid with leading edge of wing being as straight as possible despite of trapezoid and possible negative sweep (these should be on the trailing edge). This is to maximize laminar flow and minimize spanwise cross flow.
• V-tail (favorable for spin recovery and looks)
• no protrusions in the front of fuselage
• smooth accurate surface in fuselage and wings (sailplane quality)
• molded composite construction
• turbo conversion (single or twin cascade turbo)
• electric turbo compounding (hybrid propulsion)
• wing tip turbines (hybrid propulsion)
• additional electric motors (brushless DC) (hybrid propulsion)
• 5 minute lithium-ion battery pack for improved takeoff performance for escaping single engine situation in engine failure occurring in initial climb out from the runway, without a crash
• Consequence of the first points: high L/D ratio -> acceptable climb performance despite of low power
• Tip airfoil stalls at higher angle of attack than the root airfoil
• wing cuff
• aileron fence
• turbulator tape (transition fixed before separation bubble)
• vortex generators

How range requirement affects all these parameters

The range calculator is here:

http://gforge.katix.org/gf/project/twinzygger/scmsvn/?action=browse&path=%2F%2Acheckout%2A%2Ftrunk%2Fdata%2FRangeCalculator.ods

FrontPage

The following alternatives have been considered:

Under consideration or selected layout

When selection process completes, there will be only 1 alternative remaining, other alternatives are moved under topic rejected layout alternatives. Each alternative is documented why it was either selected as a candidate or why it was rejected.

Conventional twin tractor

Trimaran tractor

This alternative looks quite much like Globalflyer. The difference is that the left and right pods have propeller
on front of them.

The configuration layout comprises of following items:

- three pods

- very high aspect ratio wing

- two tail booms, one behind each engine pod

- minimal fuselage pod, optimal fineness ratio

- the pods are connected to the wing from high wing position

- there are three landing gears in this configuration, nose gear in the center pod and main gear in the two engine pods

Open issues:

Effect of propeller slipstream to laminar flow wing behind the prop and compared to clean pusher config.

Historical examples:

P38 Lightning http://fi.wikipedia.org/wiki/P-38_Lightning
Scaled Global Flyer http://planetagadget.com/wp-content/uploads/2007/09/globalflyer.jpg

Twin fuselage tractor

The layout comprises of the followings:

- two pods

- two tailbooms

- left fuselage has cockpit on it

- right fuselage has no cockpit, but only engine and baggage space

- there are four landing gears in this configuration, nose gear for each fuselage and the main gear for each fuselage

Open issues:

Effect of propeller slipstream to laminar flow wing behind the prop and compared to clean pusher config.

Historical examples:

Scaled White Knight Two

Conventional twin tractor

"Doing it all without trying and learning anything new"

Open issues:

Effect of propeller slipstream to laminar flow wing behind the prop and compared to clean pusher config.

Historical examples:

Diamond DA42

Beech King Air

Conventional twin pusher

 Historical examples:

EM-11 Orka

Rejected layouts

Tandem wing

Tandem wing pusher

 Similar to Rutan Proteus. Rejected due to low Clmax and 1/2 effective span because of downwash.

Tandem wing tractor

Similar to Rutan Proteus but with tractor engines. Rejected due to low Clmax and 1/2 effective span because of downwash.

Three surface wing

Three surface twin pusher

Rejected because of complicated aerodynamic layout. 

Historical examples:

Piaggio P180 Avanti

Three surface twin tractor

Rejected because of complicated aerodynamic layout. 

Flying wing

Rejected because of low Clmax.

Canard pusher

 Rejected due to too low Clmax.

Boom tail push-pull

Rejected due to prop inefficiency of this configuration.

Engine alternatives

Modularity is a design point in this design. The idea is that several different engine types can be used for the same airframe.

Read more about this on the ModularConcept -page.

Takeoff calculator spreadsheet was used to estimate rough gross weights for each different engine alternative.

Download takeoff calculator spreadsheet

HKS700E

• 60 hp
• wing loading and gross weight limit has to be set so that takeoff is possible with this engine and engine failure will be no worse than on Diamond DA42 Twin Star. 
• Rough estimate of gross weight: 880 kg long range, wing loading 20 lbs/sqft, 750 kg short range.

HKS700T

• 80 hp

Rotax 912UL

Rotax 912ULS

Rotax 914

Rotax 912-turbo

• This is the choice for the high altitude model
• Upper edge of the wing loading gets realized here
• Rough estimate of the gross weight: 1000 kg, ultimate long range = 1100 kg.

Jabiru 2200

Jabiru 3300

 Lycoming IO-235

Continental IO-240

Continental IOF-240

 FrontPage

http://www.asdl.gatech.edu/teams/ureti/AnnualReview2007/2.1.2_Methods_Soban_vFinal.pdf
http://www.national.spacegrant.org/meetings/presentations/2008-Spr_National/OSGC%20UAV.ppt -
http://www.gizmag.com/darpa-advances-plans-five-year-non-stop-flying-machine/9210/
http://www.aviationweek.com/aw/blogs/defense/index.jsp?plckController=Blog&plckScript=blogScript&plckElementId=blogDest&plckBlogPage=BlogViewPost&plckPostId=Blog%3a27ec4a53-dcc8-42d0-bd3a-01329aef79a7Post%3aed73c824-e7b3-4166-b19d-481355b28074
http://blog.wired.com/defense/2008/04/video.html
http://www.flightglobal.com/articles/2007/09/10/216711/pictures-qinetiqs-zephyr-claims-uav-endurance-record.html
http://www.flightglobal.com/articles/2007/09/10/216711/pictures-qinetiqs-zephyr-claims-uav-endurance-record.html

Project team members

KaroliinaSalminen (Project manager, Project Owner)

JukkaMakela (inventor)

KateAlhola (Project owner)

Project information

Product backlog: ProductBacklog

Current sprint : N/A - sprints not started

Sprint backlog: SprintXXXBackLog

Table of contents

1. Concept description ConceptDescription

1.1 Modular concept ModularConcept

2. Design alternatives DesignAlternatives

2.1 Limit curve analysis (rajakäyräanalyysi) for the design parameters. RajaKayraAnalyysi

2.2 Conceptual design for each alternative ConceptualContents

3. Enabling technologies EnablingTechnologies

4. Wing considerations WingConsiderations

5. RC test model RCTestModel

6. Chosen configuration alternative ChosenAlternative

7. Weight estimation WeightEstimation

8. Performance estimation PerformanceEstimation

9. Preliminary layout PreliminaryLayout

10. Detailed design DetailedDesign

11. Structural design StructuralDesign

11.1 Materials MaterialsList

11.2 Hardware HardwareList

11.3 Motors MotorsLinks

12. Flight testing FlightTesting

13. Reference Library ReferenceLibrary

13.1 Airfoil links AirfoilLinks

14. Design Software DesignSoftware

15. Miscellaneous Tech papers (NASA, AIAA, final reports etc.) MiscTechPapers

This page is a link list for brushless DC motors of adequate size to fit for the purpose

2.5 kW peak

http://www.rctoys.com/rc-toys-and-parts/HI-6332-230/RC-PARTS-BRUSHLESS-MOTORS-HIMAX.html

2 kW peak

http://www.hackerbrushless.com/motorDetails.aspx?series=A40%20Electric%20Turbine

3 kW peak

http://www.hackerbrushless.com/motorDetails.aspx?series=A50%20Electric%20Turbine

http://www.aero-model.com/motordetails.aspx?series=A50+Electric+Turbine&style=L

5 kW peak

http://www.hackerbrushless.com/motorDetails.aspx?series=A80

http://www.aero-model.com/motordetails.aspx?series=A80&style=10

7 kW - 8.8 kW peak

http://www.aero-model.com/motordetails.aspx?series=A100/200&style=8

15 kW peak

http://www.hackerbrushless.com/motorDetails.aspx?series=A100/200