IBIS, say what?
Ornithologists call these colourful birds Plegadis Chihi, at least if it's the white faced variety.
Just to preempt remarks from astute readers: the observer depicted on the right is indeed at home in the Plegadis taxonomy, but obviously is not of the white faced variety...
In 2007 it was exactly 20 years ago that Jean Claude Junqua and his father Roger Junqua presented F-PJQA, their proof of concept "RJ.02 Volucelle", at the 1987 RSA Fly-in, which took place at Brienne-le-Chateau (LFFN).
Since then, Volucelle was developed into the first IBIS prototype (intially registered as F-WZGY and then after certification as F-PZGY). The next development step was the RJ.03 IBIS as we know it today, of which P-PBSM (built by Stéphane Malandain and Frédéric Barbeau) was the first to fly. Twenty years of development and incremental refinement is a milestone allright. Congratulations to Jean Claude and his team!
I've written an article about my visiting the 2007 RSA fly-in, check it out.
- Wooden construction - except for the nose cone and the canopy, there are no compound curves, so it's easy to build with the usual hand tools. Some powertools ease the process, but tool requirements are still extremely modest.
- Flaperons on the main wing - as far as I know, no other canard homebuilt aircraft, Cozy, VariEze and the like sport a control surface on the main wing that acts as a flap. This reduces landing speed, alleviating part of what some consider to be a disadvantage of canard aircraft in general.
- Low power requirements - meaning low procurement, operating and maintainance costs. IBIS requires an engine between 60 - 80 HP. Most of the time, a VW derivative (Great Plains, JPX, AeroVee, Limbach, Sauer, etc.) is used. The designer's son re-engined his IBIS with a Jabiru 2200, but after about 300 hours decided to revert F-PBIS back to a VW-based aero engine. Depending on installed power, a different maximum take-off weight needs to be respected: with VW-derived (or similar) engines of up to 1835 CC the maximum take-off weight is 470 kg, for larger engines (from 1915cc upwards) the AUW is 490 kg.
- Decent performance - what can I say, see the table below:
|Performance at AUW (470Kg /1034 lbs) with 60 HP VW-engine||Knots||MPH||Km/h|
|Normal cruise @ 65% power setting||108||124||200|
|Long range cruise||97||112||180|
|Maximum range is 485 NM (almost 900 Km) + VFR reserve|
The fuselage is a spruce, douglas fir or pine structure set up with 7 frames, 4 longerons and some diagonal struts. It is covered up with thin birch plywood, in the cockpit area both inside and out - the void in between filled with foam.
Both tandem seats have full controls, with the exception of a flap actuation, which is only available in the front cockpit.
The instrument panel is in front. If needed a tiny pod with the most essential instruments can be mounted in the rear. Some Ibis builders put essential instruments on the outside of the front cockpit panel, so that the GIB (gal/guy in the backseat) can observe these by looking over the shoulders of the front seat occupant. This saves weight and money, both always important, but you end up with a non-standard instrument layout in the front.
The canopy is a single piece of Lexan or Plexiglass, much like those of modern sailplanes. It opens to starboard, so you mount the ship on the port side.
This is where the term composite comes in. Basically, the structure is rather conventional, employing a wooden box spar and wooden ribs. Where it gets interesting is how foam is used to fill up the space between the ribs. Also, the 1 mm plywood wing covering is vacuumbagged while the glue/resin sets. This combination of vacuumbagged birch plywood covering, stiffened up by foam underneath, results in a very light and smooth wing skin structure.
The main wing is a single piece of structure, so finding a place to build it can be a bit awkward. Then again, the constant chord configuration - no wash-out, mind you - makes it simple to build.
As to the aerodynamics: the main wing sports a NASA/Langley LS-GA(W) section. I think it's the 0417 GA(W)-1, but I'll edit this sections as soon as I have verified this.
The canard wing is built similarly: wooden box spar, wooden ribs with the spaces in between filled with foam.
This structure is completely covered by 0.8 mm birch plywood using a vacuum bagging process. Light and strong! Hans Holsink (from The Netherlands) reports a weight of 7.5 kgs for his completed canard + elevator, sanded and primed as well - but without the paint job.
The canard uses a single slotted NACA 23012 section profile with a 25%c elevator.
The designer's website used to state that any engine from 60 - 80 HP with a maximum weight of up to 75 kgs may be mounted. Since then, his website has become a bit more specific (perhaps to bring it in tune with the building manual ?) and mentions only four or five approved engines.
The published performance figures were those of an IBIS that uses a fixed pitch prop mounted on a VW 1835 CC (60 HP) engine.
Come to think of it, did I mention that the engine is in the back?
The tricycle non-retractible landing gear has a steerable nosewheel carriage that is fabricated from steel tubes. The main gear is an arch laminated from solid wood (ash).
- Payload restrictions - first and foremost I must mention that with two grown-ups on board, IBIS is not a long range travelling machine. 'Weight & Balance' is important on any plane. The 'balance' part is easy, as the rear seat is almost in/on CG. As long as the pilot flying in the front seat is within weight limits, the CG will be within its designated range. With two adults on board, it's likely that you can't fill up the tank to the rim, as you would go over the maximum take-off weight.
©2004-2012 IBIS RJ.03 "The French Canard" homebuilt aircraft project
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