Conversation with Bruno Gaboriaux – Colab Systems

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I had a long conversation with Bruno who is a model plane builder with long experience with this concept of wings. (Sounds like he’s been involved in building Lucien’s prototypes from when Lucien invented the concept)

At first we discussed about the air-foil profile of the wings.  His opinion was the RG-15 profile was just for performances.  It would fly fast, but he prefers using a FX-62k profile that has been design for better handling flaps.
Perhaps we should build the prototype using the RG-15 and see how it goes, knowing Bruno has the experience of the FX 62-K-153/20, we could always fall back to this if ever RG-15 was giving us issues and that we needed more brake power.

He then explained me the proportions to respect.  They are very simple: the back wing has to be 2 cords further back and 2 cords further down.  The tail of the plain being 3 cords away.

Side view (corrections / suggestions by Bruno)

Something he mentioned is to use balsa leading and trailing edges that we can by from a local model shop.  It helps making strong solid wings saving us using fibre glass or carbon rods.

He prefers to use tricycle landing gear.

He send me two documents.

One is just pictures of an existing model converted to the COLAB System

WAYFERER COLAB (pdf)

The second document in French who describes more in detail the COLAB.

Initiation_au_COLAB

A bit of math

Starting on the bases of a total of 3m of wings with a cord of 16cm, that gives us a surface of 300cm x 16cm = 4 800cm²
If we aim for a plane of about 1kg and that we add 4l, that gives us around 5000g/48dm² ≈ 104g/dm² (commonly acceptable values for the wing load can go up to 150g/dm²)

Safety Rules

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Flying a model plane is not an easy thing to do… much harder than driving a car.  How long does it take to pass a driving test?

It must be understood that probably none of our team (not even me 🙁 ) will get a chance to ever fly the real model as the real model can only be flown under the supervision of a British Model Flying Association (BMFA) instructor.

Under no circumstances will any members of the Mosaic Clubhouse be allowed to power on the plane without the presence of someone the BMFA would regard as of “trusted experience”.

The engine is about 450W of power… about as a much as this

Any tests during the building process requiring powering the receiver will be done without a propeller fitted on the engine.

The only time a propeller will be fitted on the engine will be in presence of a BMFA member.

THE MODEL WILL ONLY BE PERMITTED TO FLY UNDER SUPERVISION OF A BMFA INSTRUCTOR.

Even though members of the Mosaic Clubhouse won’t be able to fly the actual model, we’ll make every effort to put together a version we can fly on a simulator (X-plane free is limited to 10min flying… the competition is 10min 🙂 )  If we do well on the simulation, there is always a chance we’ll be able to convince a BMFA instructor we could have the commands for a few minutes 🙂

After speaking with Terry Eato (Club Support Officer BMFA) I have no doubt we will have, that day, a pilot to fly the plane at it’s best.  To honour all those people paid with a smile, who are so candidly offering their help, we’ll have to build the nicest and smoothest plane to fly that day!

Thanks you for reading this 🙂

The wings

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Information on how wings fly: http://www.cfse.ch/site/topics-wings.htm

Links:

Notes:

All the experienced modellers I’ve met, each time I mentioned heavy lift, would always come up with the RG-15 profile… must be something about it 🙂

profile RG15 A ?? 150~160mm cord, wingspan 1.5m
Ailerons of about 20% on all the lengths

The wings would be cut into a block of foam using a hot wire.

The wing will be reinforced by a carbon tube (8~10mm?)

A layer of grade 160 fibre glass and a thin layer of balsa is added around the foam core (sounds solid to me).  Covered with solar film, the wings will have a nice gloss finish. (Is it a sandwiched wing?)

rg15a213

This is a Rolf Girsberger RG 15A 2.5/13.0 air-foil

rg15a111

Rolf Girsberger RG 15A-1.8/11.0 air-foil

FX 62-K-153/20

FX 62-K-153/20

Victor Rojas

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I’m Peruvian and I’ve been living in London since October 2004. I came to the UK to face new challenges in my life.
Trained as a structural engineer (BSc in civil engineering, 1990 UNI-Lima, Perú, postgraduate studies, 1994 Chiba University, Japan and short-term consultant, 2008 Imperial College London). From 2001 at 2004 working as regional advisor in disaster management for the World Health Organisation in South-America.
Now, working in volunteering positions in the mental health sector in my recovery process as service user of SLaM-NHS.
I met Stefano at Mosaic Clubhouse in Atkin Road. He told me his ideas of flying and to participate in a competition out of London. I became very interested and excited. I want to contribute in this project with my expertise in resistance of materials, stability, structural design and optimisation. I strongly believe that the success of any challenge is working as a team, creativity and motivation. If you dream it, you can do it!

AIRCRAFT CONFIGURATION

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E.3    AIRCRAFT CONFIGURATION
E3.1    Only fixed wing designs will be permitted to enter the competition. The maximum total wingspan is to be 1500mm.
E3.2    Propulsion unit is to consist of one E-flight Power 10 motor and one E- flight 40A speed controller (available at cost direct from the BMFA office). The battery must be a 3 cell Lithium Polymer with a capacity not to exceed 2500 mAH, the pack must have the manufacturers label with the capacity shown. A separate battery may be used to power the aircraft’s radio receiver. No modification to the motor is permitted.
E3.3    Only one flight battery may be used per flying round.
E3.4    A propeller spinner or rounded safety nut must be fitted on forward facing motors.

Deadlines

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All members of the team MUST READ this document!
ElectricLiftRules2011

[…] transport the greatest quantity of water around a predetermined triangular course in a prescribed 10 minute time slot utilising a standardised propulsion unit. […]

The competition will take place on the 6th of June 2011.

We’ll have to hand in by the 6th of May the drawings of the plane.

The judges will evaluate the drawings based on a professional standard format. Areas of evaluation will include.
Detail Completeness Explanation of structures Readability Graphical standards
A maximum of three sheets of drawings is required. The drawings will be worth 25 points.

[…]

Each team must submit a report which outlines the design philosophy of the aircraft, team roles and responsibilities, choice of configuration, payload distribution, manufacturing techniques and any practical testing undertaken. No prediction of the total payload to be transported is required. Any original or innovative ideas should be described, together with the use of unique or advanced structural techniques and materials. The report is worth 25 points and should comprise no more than six double-spaced, typewritten pages of A4 paper, including any appendices and diagrams. Minimum type size to be 12 point.

Budget

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The budget we have to start with is of £746.
With this we have to build at least one plane… and I think it would be a good idea to actually build two!
I think we should build a prototype before we start building the one that will fly on the actual competition day.

Power

First we should buy two engines + controllers from the BMFA.

  • Eflight 40amp speed controller £32.19 (rrp £72.00)
  • Eflight Power 10 motor £22.07 (rrp £49.00)
  • total: £54.28  (+ shipping?)
  • Order to be sent to <admin [at] bmfa.org> addressed to Julie Cole.
  • Props: 9×6 ??

Batteries

  • 2x 2500 3S Lipo

Building materials

Foam

I’ll look at good deals to by some EPP foam blocks. still needing to math out the volume and quality needed.

Balsa

Glue

  • Epoxy (slow + fast)
  • uhu foam glue

Carbon

  • 8x 10mm x 1m carbon tubes

Radio equipment

Servos

note: could be we can have a few standard size servos from the Thamesmead Model Club