PPRuNe Forums - Guimbal Cabri G2

This is the first article, hope you've got an hour or two......

At the beginning of 2006, the flight tests had known a certain deceleration following the non-availability of the test pilot. It is true that the French administrative system is not simple. Thus, impossible to fly when we had met the CABRI for the first time. But fortunately, the administration counts also people with a clear vision and it is besides an arbitration on the most level which made it possible the CABRI project to find its test pilot. Since, the small helicopter does not cease flying to achieve the program of certification as fast as possible. It is thus with enthusiasm that we put the course on the ground of Aix the Miles when Bruno Guimbal telephoned to us to announce the availability of the CABRI for a trial flight. The helicopter being always at the stage of certification, the structure of our article will be by definition different from our usual screen. For those which did not have the occasion to read the article of April, it should be known that Aviation International put on line on our Internet site (www.aviationinternational. aero) for free consultation. Click on the heading "the Articles" in the general menu then "Tests Helicopters". In this article, we especially will speak about our impressions at the time of our first flight in CABRI. Few people having had this privilege before us, information seem important. For obvious reasons, other aspects which we usually treat at the time of a test could not be evoked. All the financial considerations, the procedures governing the maintenance or the availability of the parts are not yet really on the agenda. For the moment, Hélicoptères Guimbal is polishing its machine and to take it along towards certification. The figures published are thus a statement of our flight and will know still certain modifications. It is a project as ambitious as promising which rose in our editorial priorities. It goes without saying we will follow the CABRI of loan. Then you in regular articles wait which will inform you of the progression of the project. Hello N°1 the CABRI of our images is the first machine in conformity with the specifications of series. A second CABRI is in the course of assembly and will take part in the validation of the parameters for certification, primarily with regard to the electric circuit and optional air-conditioning. It is thus the same machine that you already saw in our preceding paper. In preliminary documentation, Guimbal announces an empty weight of 430 kg for a MTOW of 700 kg. The first CABRI weighs 448 kg. This weight includes/understands 23 kg for the material of acquisition of the data, there are sensors really everywhere. Moreover, screen LCD present side pilot is precisely used for the visualization of this information. The standard appliances will of course be deprived of these instruments. At the time our trial flight, the tank posts 64 liters and the crew adds up 180 kg, which gives us a mass on the takeoff of 675 kg. Holding account of an average time consumption of 35 liters, our two hours endurance close would have made it possible to carry 25 more kg of luggage. Exchanging the test pilot of Guimbal against my wife, I would have gained 30 kg, but since the women travel with beautycase and other ustensils, the situation for my luggage would hardly have changed... But let us cease joking and retain that the CABRI truly makes it possible to leave with two people and luggage with reasonable autonomy carburizing; it is a very good point. Extremely of this theoretical information, it is time to go on the tarmac and to begin the pre-flight. Annoyed with Internet? For those which have bad memory and are annoyed with Internet and which thus could not consult our last article, here nevertheless a small recall: Bruno Guimbal is old of Eurocopter which in 1984 had the vision to want to build a light piston helicopter for two people profiting from current technology. CABRI, fruit of this reflexion, is an helicopter whose external forms cannot deny a certain influence of last Eurocopter de Bruno. With force to see Squirrels and Hummingbirds, normal that that leaves traces. The three-bladed rotor in composites is pulled by a BTP house which distributes a part of the 145 cv towards an anti-torque device Fenestron style. Lycoming O-360 receives a system "antigrivrage carburizing Guimbal". Hear by-there Bruno Guimbal invented an automatic defrosting equipment to electric drive which is ordered by the MFD, which posts the operation of the device besides. The nominal nominal output of 180 cv is détarée to 145 cv. The conceptual principle of a helicopter wants that one establishes the size of the BTP compared to the engine output available to ceiling HES. On the sea level, the density of the helping air, the requirement in power is less. These 145 cv correspond to 2' 650 rpm and a pressure of admission of 24,7 inches in conditions ISA on the sea level. Thus, the pilot reads 100% on his MFD. The electronics of the CABRI allows a variable use of the turns rotor. You will thus read 520-540 NR according to the need for the margin of power. The posting of the power on the MFD is calculated by holding account of the altitude-density of the moment. The CABRI will be the first light helicopter certified according to standards' EASA SC 27. That implies in particular very strict anti-crash landing measurements. All modern technology is used on board CABRI. Olivier Gensse While I discuss with Bruno Guimbal, the test pilot arrived. Olivier Gensse is a strapping fellow with a pleasant smile. Graduate of Epner with Istres and having taken part in the development of the EC-225, Olivier knows what it speaks. Its course as a test pilot in the center of the flight tests allows a scientific approach of the phenomena of the flights. After a small briefing, we move towards the machine. The pre-flight is not complicated, all is easily accessible and two side caps open allowing the inspection of mechanics. A footboard on the right makes it possible to check the head rotor. All is made to facilitate the detection of a possible problem without finding the hands in dirty oil, the pilots of helicopters of old generation know what I want to say. It is time to settle on board. Each detail... To open the CABRI, anything simpler! Forget the ancient bunch of keys of your Agusta or Dolphin and support simply on a remote control! What became normal on board each Renault CLIO finally made its entry in the general aviation! It is true that I always had much evil to include/understand why it was necessary to spend several million euros to have an helicopter provided with the locks with Renault Gordini! It is not that a detail will say some. Admittedly, but it is precisely the good proportioning of the spices which will make that a dish made up of the best ingredients will leave an unforgettable impression in your palate. This remote control allowing the unlocking of the doors of the CABRI and at the same time the desactivation of the antidémarrage is a good example to illustrate the state of mind of Bruno Guimbal. Contrary to the genious engineers from Sikorsky or Dassault, Bruno is not satisfied to invent an innovating head rotor. The man thinks of any detail allowing the future purchaser to obtain a product close to the perfection. The orders side copilot are dismounted without tools to line up in a small interior trunk, space luggage add up 192 liters; very at thought and reflected summer. That seems so perfect that it is already almost equivocal. On board Installed on board, I find nevertheless with râler. Ouf, finally! Wouldn't the CABRI thus be perfect? You reassure, my criticisms are thin and besides Bruno Guimbal indicates that this kind of comments is more than welcome to polish the product before the final definition of any part. It is true that installed on board, I miss a little place. The base of the seats misses length for the large ones, the support of the legs is not optimal. From their anti-crash landing design with energy absorption, the seats are fixed, but a lumbar adjustment could have been integrated into the great pleasure of customers mainly "hard-working of office" with more or less accentuated back painses. For the moment, the position of the swing bars is still fixed, the later possibility to regulate them will improve certainly the situation for the large gauges like besides for the small ones. No the problem on the other hand for the shoulders or the head, space is generous. The safety belts standard harness four points with roller marrying safety and comfort are excellent. The catches helmets, the circuit breakers, the horameter and the containing hydrocarbon tap are placed on the electric control panel between the two pilots. The closing of the doors highlights a simple and effective system. The joints do well their work, the sealing of the doors is not a problem. The position of the orders of flight is pleasant, the cyclic fall well into the hand. The pitch control for the pilot is on the central console. For the large ones, the position is thus a little high, but that gene not too. To facilitate the access on board passenger, the pitch control on the left is located 3 cm lower. The linkage throttle style traditional handle of motor bike has a first position which makes it possible to regulate the power between 0 and 100 %. a second position maintain the order to 0 % to avoid a handing-over in accidental power at the time of autorotations. Ordered by springs, this system makes it possible to return quickly of normal use while ensuring a good safety in drive, it is very well seen. At its end, the order is hollow to place the switch for the governor as well as the button of starting. Richness control as brake rotor are with the ceiling. Let us recall that an helicopter with pistons controls normally always full rich person, it does not matter altitude. The current flight manuals do not lay down to impoverish even if that could decrease consumption in cruising and increase the longevity of the engine. On the CABRI, Bruno Guimbal wishes that the informed pilot be able to use the mixture in cruising speed in altitude, but attention, an engine of helicopter stops very quickly and it is not a question of mixturer on the thin side. Despite everything the modernism on board CABRI, the richness control is of course used to choke the engine at the end of each mission. Also with the ceiling switches for lightings 1&2. It should be remembered that with its lighting electronic TDCI, the engine of the CABRI has only one magneto which is useful in backup in the improbable case of a failure of Plasma. This ignition system was the subject of a STC by Hélicoptères Guimbal. The central console is sufficiently large to lodge all the instruments while keeping a beautiful visibility for the crew. Surprising in the medium of the table, the presence of a MFD of beautiful invoice of a diagonal of 26 cm. The screen comprises especially an account turns intelligent engine-rotor with detection of desynchronization and a calculator of margin of power which posts the gross margin of power available, while indicating if this margin is due to the couple or gases. In option, a gauge of precision with posting of remaining autonomy in minutes is also present. The additional functions are: pressure and temperature of oil, gasoline pressure, temperature cylinder head, temperature carburettor with indication of the interlocking of the automatic carburizing heating, ammeter, EGT, detection filings BTP and PTA, outside temperature, stop watch, show and carbon monoxide detector. I note a perfectible legibility however. Without sunglasses, the screen appears not very luminous to me and once my Ray-Round of applause with polarizing glasses fitted, the reading of the MFD becomes really difficult. But attention: that is only one personal perception and I must add that I know my eyes since knowing sufficiently a long time that they need much luminosity. However, a thing is certain: in the current state of the things, the MFD is less readable than the traditional clocks, even if Guimbal announces a profit of luminosity of 30% on the future flagstones of series. To each potential buyer thus to test, it is a really subjective feeling. On the models of series, the luminosity will be also modifiable, essential besides for the night flight. Startup the procedure of startup of the CABRI is simplest that I ever met on a piston helicopter. All is simple and logical. Lycoming is cold, therefore four injections with the throttle lever. Then the sequence of the switches is logical, one starts on the left to finish on the right. Thus: battery, pump, strobe, alternator, clutch, headlights, then side-lights. The gases remain with the neutral when Olivier says to me to start. A small blow on the button, Lyco awakes, it is as simple as on board Mercedes, thank you the electronic ignition made by Guimbal. Olivier makes me assemble the power to 15% to couple. On the models delivered to the customers, starting will be done with the idle, which is very stable, thank you once more modern lighting. The temperatures are in the green, we are ready to relocate. In this end of afternoon of June, a small back wind of 15 kts cherishes the CABRI. Olivier, very trustful, crosses the hands and lets me take off. Performances surprising As of my first stationary following back takeoff wind, the stability of the CABRI is surprising. But I also immediately note a certain hardness in the orders. We are far from the flexible controls of a hydraulic assistance as to edge of a one or turbine-powered helicopter that of a Robinson R44. For stage this established fact, the CABRI has a trim in the shape of Chinese hat on the cyclic one. That resembles with the device met on certain rigid rotor machines like the EC-135. According to flying conditions', it is thus necessary to find the position of the trim which is appropriate. With the beginning, that can appear diverting, but gradually, the use of the Chinese hat becomes instinctive. Moreover, the piloting of the CABRI is not without evoking a certain resemblance to that of this twin-engine of Eurocopter. Each action on the handle results in an immediate movement of the cell, it is not as on Bell where one perceives initially the rotor tilt before the movement of the cell. After a little work on the ground, I proceed to the first takeoff. Useless to post more power, it is enough to incline the rotor forwards then the rotor of the CABRI devours the air with a rather frank acceleration, it is surprising for a small power of 145 cv. 50 kts is the good value to be retained for the rise and that is also worth for the approach as for autorotation. On the level, acceleration towards 90 kts is very fast, then it is necessary to look after the line of flight to reach the cruising speed maximum that Guimbal announces with 100 kts. The day of our test, we butted against 98 kts, but let us not forget that we are on board first CABRI and that it still will undergo adjustments and improvements. The noise level is rather low. I measure 94 dBa on the ground then 95 dBa during the rise. As soon as the helicopter takes speed, the relative wind starts to mask the noise of the rotor, the posting of our sonometer drops to 90 dBa in economical cruise (90% of power give 90 kts) then is stabilized to 88 dBa in fast cruising. We have flown now for 20 minutes and I start with better smelling the machine. Us here ready for a first approach. With my eyes "eaters of luminosity" masked by glasses, I have evil to see the indication of the power on the MFD. I thus regulate with the conk and that seems to be appropriate to Olivier as in the CABRI because I stop the machine at the point wanted in hover. I am really impressed by the disconcerting facility with which this light helicopter is controlled, even if I continue to force too much on the cyclic one not having bored all the secrecies of the compensator yet. And here, it set out again for a turn. In back wind, arrived at cruising speed, the CABRI is stable but vibrates. It is not worse than on some other machines, but we are far from a flying carpet. Of return on the ground, Bruno Guimbal will explain that it did not develop the procedure of balancing bus yet with the present stage, the blades are still dismounted permanently. It is time to proceed to autorotations. Once more, the CABRI surprises by its extreme handiness and a stability which refers to machines much heavier. Definitely, the helicopter of Guimbal makes much more than to only resemble a Squirrel visually! In autorotation, the rate of descent is frank, it is not a sailplane like Bell 47. But I note a beautiful inertia rotor which forgives with thoughtless not immediately not to lower the collective once the engine failure noted. The regulation of the turns rotor during the descent is easy. Moreover, the beach between 400 and 630 turns NR is comfortable and allows autorots in full safety for mechanics, even if the pilot, stressed by the situation, neglects to monitor his turns. A good 50 kts with the airspeed indicator corresponds at a vertical speed of 1' 400 ft/min. In approach of the ground, the flare resembles a good rounded as on a light plane, which breaks the variometer well. Thereafter, it is enough to relieve with the step and to put the machine flat. It is then on its solid anti-wear aluminium shoes with tungsten carbide shoes that we slip on the tar during a few meters to stop us carefully, it is rather magic. It is a procedure simple and easy to repeat, even if that does not give an absolute precision to touch exactly the point envisaged. With a little less speed, autorotation gains in precision but the operation is reserved to the experienced pilot. The tests showed a smoothness of 3.6, which is remarkable. We set out again for some evolutions close to the ground. Well trimé, the CABRI is able to hold the stationary one during good two seconds while we release ALL the orders, it is rather remarkable. It should be said that the last helicopter which enabled me to remain in hover was the EC-155, a monster of technology equipped with a numerical autopilot four axes of last generation. Set out again in flight with our CABRI and sensitized on the fact that the machine seems balanced very well, I realize that it is completely possible to fly in....... continued next post

........cruising without swing bar because this one keeps its position well once the ball centered in the medium. It is thus a very balanced helicopter which Bruno Guimbal is on the point of certifying. Small Tiger or Olivier? During all our evolutions, I am bluffé by the extreme handiness and the reactivity of the CABRI. Considering his careened anti-torque rotor, I expected to have to anticipate with the foot as it is of habit with any helicopter having a Small window. But it of it is nothing. Each action on the swing bar results immediately in a movement into lace. To anticipate? You speak! Of course, that is also worth for the cyclic one. It is true, the handle a little hard, that is really made think of a rigid rotor. But just like on rigid rotor helicopter, each movement of cyclic makes react immediately. One then obtains a very reactive helicopter without giving to the pilot the feeling of an unstable machine. I think that improved helicopters of combat as the Tiger must convey similar feelings, all things considered. After having abused the machine, I yield the orders to Olivier to discover the possibilities of the CABRI. And there, I am truly époustouflé. Between Olivier Gensse who is a test pilot out par and the small CABRI with the unsuspected performances, the cocktail is clashing. At all events, the small demonstration highlights several points: the CABRI has a so broad flight envelope that the normal pilot will fly in all circumstances with a beautiful safety margin. For the pilot beginning, the CABRI will be much easier to tame than R22 and the experienced pilot will be able to find at each hour of new possibilities and reasons to open out. Only 145 cv? It is necessary to acknowledge that by seeing this machine planned for a maximum weight of 700 kg, I have instinctively dreaded to miss power. It is true, 145 cv, that does not make much. But after my meeting in flight, near to the maximum mass, I am obliged to regard my first judgement as hasty. It is true that if industry were finally able to propose a reliable and light engine developing 200 cv, the rotor of race of the CABRI could certainly be still well better expressed. But while waiting, the new tricolour helicopter is placed with the same sign as all the other manufacturers. The day of the test, the conditions weather were ISA +9°C, which did not seem to disturb the CABRI. During all my flight, I seldom had the feeling to miss power. It is true that at the time of a a little fast approach with strong slope, one does not have the same power as with a turbine to force the CABRI to stop. But it is enough to pull up a little more because the capacity of the rotor slightly charged, with its modern profile with strong capacity of bearing pressure, still makes it possible to fly with only 380 turns rotor. In comparison with all the other helicopters with pistons, it should be said that the machine of Bruno Guimbal is very astonishing. Very appreciable also this reactivity with the orders which makes it possible to carry out even the operations most dared with a perfect ease. For the small history, let us note that the CABRI holds several records of world (approved FAI): Olivier Gensse carried out inter alia the machine to 6' 658 m of altitude, that corresponds to the FL 220! Not only for the schools It is necessary to acknowledge that the traditional two-seater helicopters have especially a vocation as a teaching aid. Imposing a fine and pure piloting, I always liked small R22 to learn "If you can control R22, you will be able all to control..." told me the instructor of my beginnings. But to travel, the absence of trunk and a reduced payload penalize small Robi. Schweizer 300 makes it possible on the other hand to take along some personal effects and its broad front bench is convivial even enough for three people. But by this concept, resistance in the air is considerable and a cruising speed rather timid results from it. Bruno Guimbal understood well that to design a revolutionary helicopter, it was necessary well to exceed the stage of the machine which nothing but does "well fly". The small trunk inside makes it possible to place the orders of flight, two helmets and various small equipment and even your picnic. For those which hope to use it for special missions, the place could also be useful for the installation of material various like equipment of transmission for video uses for example. The external baggage hold makes dribble of desire any owner of a MANDELEVIUM 500: to carry two bags of cabin does not pose a problem for the CABRI. At the time when we write these lines, of many parameters are not validated yet. Thus, the figures of performances and the abacuses which we publish are the information provided on a purely strictly indicative basis. Even if there are very good lucks that the CABRI reaches these values, Bruno Guimbal indicates that the final values will be available in the months which follow. The acquisition of the data at the time of a certification is a long process comprising of many parameters. But we will follow this project of near and will deliver the evolution at the time of future tests to you. In the case of the CABRI, the compromise between performances, comfort and safety seems particularly well defined. The helicopter is announced with a cruising speed of 100 kts for Vne of 125 kts, knowing that Olivier Gensse validated the resistance of the machine at the time of tests to speeds of 140 kts, which is more than the margin of the 11% lawful. Moreover, a wind noise, left similar "flap-flap" to the noise of large Bell, appears gradually as of 130 kts. It is an excellent warning signal for the thoughtless pilot who would have omitted to notice that it was found with a rate of fall bordering the 4' 000 ft/min. This Vne high shows the great potential of this rotor. The ceiling except ground effect is not validated yet bus of the adjustments to contain the temperature of the engine are in hand. The ceiling OF was validated with 8 000 ft: that should be enough to go to the ski to two. The immense anti-crash tank of 170 L usable authorizes an endurance of approximately five hours. By this rather single combination of qualities, the CABRI will be of course a very good machine for the schools and clubs, but could also be useful afterwards for true voyages for the members of the structure having learned how to fly on the type. For the private one which is already pilot of helicopter but which did not cross the step of the purchase yet, the CABRI will be a very convincing argument. Made in France It is true that the French aircraft do not have the reputation to be cheap. In this moment, Bruno Guimbal accepts purchase orders relating to an amount of 240' 000? HT. This tariff includes/understands rather complete equipment. We note especially this locking centralized by remote control, the double dismountable orders without tools, a CO detector and an automatic carburizing reheating. This last point appears to us the of greattest importance on board a piston helicopter. In option, the customer will be able to make install an air-conditioning, a buoyancy of help, a dashboard VSV or a containing hydrocarbon flowmeter with posting of autonomy. For maintenance, Hélicoptères Guimbal aims a first visit at 100 hours, then one 500 H and a 4' 000 H, left major inspection. Lycoming requires a draining with change of the filters all the 50 H. The potentials aimed for the mechanical sets are of 4' 000 h. Bruno Guimbal indicates to want to manufacture a machine whose maintenance will not be compromised by calendar thrusts. It is highly desirable that this wish becomes reality. For this reason, it should be indicated that the company Hélicoptères Guimbal gives the impression to have succeeded in creating a fabulous machine but does not seem for the moment not too much to worry about the other aspects to propose a complete solution. Besides it is advisable to note that contrary to our practices, we are not able to publish curves of performances nor even a three-view drawing: although promised with repetition by Guimbal, we never received them. This Marseilles side disturbs and does not make serious. The man has only two arms and only one head, we agree on it, but the promises are made to be held and it remains to be hoped that the future customers who currently sign the purchase orders will not have nasty surprises on this side. The CABRI is placed as a direct competitor compared to Robinson 22 and the range of Schweizer 300. These two machines are tariffed in dollars, which is currently a very good news for any owner of euros. It as should be known as companies as Socata post the price of their machines in American dollar, contrary to Eurocopter which currency in euros. It is obvious that long-term, the success of the CABRI will be also closely related to its penetration of the American market. It is only while entering a true logic of industrial production that Hélicoptères Guimbal will be able to be established as a principal actor in the market of the revolving aerofoils. It is by a logic of mass that it will be possible to ensure a SAV the height of best, I think of companies like Bell or Cessna. Particular context That made now more than 30 years that the last two-seater piston helicopter was designed. With the CABRI, the company around Bruno Guimbal proposes a truly innovative machine. Very good performances, real versatility, great volumes for occupants and luggage, high level of safety, the result seems without call: us here opposite the first piston helicopter for two people of the third millenium. After my trial flight, the conclusion is obvious: if I were to buy a two-seater helicopter, my choice would go towards a CABRI. This decision and largely moved by qualities in flight of the machine and its level of safety. The small reserves issued in our article are a little normal insofar as it acts of the first helicopter of a new company.
Certification is always planned for the end of this year 2006 and the first customers will have their CABRI in 2007 according to current information's. A good idea is thus to go to see Bruno Guimbal at the time of your next Aix-en-Provence passage. But go ahead especially to sign orders because the man likes to chatter and any hour that you will fly to his kindness will delay for as much certification! And that, not, it would be really too regrettable according to what I could note at the time of my trial flight... Philippe Bavaria