Wednesday, December 31, 2014

New Year best wishes !


My best wishes to all RC glider pilots from all over the world for a successful and healthy New Year, plenty of happiness, joy, friendship, successes, with plenty of unforgettable moments, many new planes, a wonderfull flying season with good wind, thermals, new slopes, and much more if possible ! 

Mes meilleurs vœux pour la nouvelle année, que je vous souhaite pleine de succès, de joie et bonheur, d'amitié, de bonne santé, avec plein de moments inoubliables, de nouveaux planeurs, un super saison avec du vent ou des thermiques, de nouvelles pentes et bien plus encore si possible !

Wednesday, December 3, 2014

RC Pilot, december issue

My review (in French) of the Vagabond from Hacker Model has been published in the december issue of RC-Pilot (http://www.rcpilot-online.com/).



RC Soaring Digest, december issue

I forgot to relay the information that the december issue of RC Soaring Digest is available. It is very large with many articles and includes my report about the F3F worldchampionship in Donovaly and the review of the Vagabond from Hacker Model.

You can download this issue here:  http://www.rcsoaringdigest.com/


Tuesday, December 2, 2014

Video: Fly in Iceland

Filmed with a quadricopter (TBS discovery pro) by Thibaud Ringenbach, who is also a F3F pilot. Behind this 5:40s, they are  41 flights corresponding to 7 hours in the air, "only" 85Gb of data and 4 month of editing.

The result is this hauntingly beautiful video !


Sunday, November 30, 2014

A world premiere ?


Thierry Monnot 3D printed the fuselage master of his new VTPR plane called the Minilimande. After many hours of printing, and a cost of 40 euros of material, Thierry obtained this multipart fuselage.


The approach is very innovative, for a super result. The rest of the work remains usual with sanding, gelcoat before to obtain a final master to be moulded.

You can find more pictures and information on his blog: The Breizh Maker


Thursday, November 27, 2014

Flying the Rotmilan Midi


Read also:
Part 1: Kit overview
Part 2: Assembly

After testing many many F3F sailplanes over the last 20 years, I can say that I can split them in 2 main families: the "Slippy" and the "Grippy". The Slippy includes planes having a fast natural speed, even with low ballast. The grippy are  planes providing lots of lift in the turn and that can carry lots of ballast, and most of the time need a minimum weight to fly fast. The Rotmilan is part of the Slippy family, that is to say using a section which is more naturaly fast.



In small condition, the Rotmilan is fine but cannot do tight turns with low lift. It starts to breath in medium condition and is an easy and well mannered plane. In stonger condition, it doesn't need too much ballast, and can manage the crossed wind good.  The Rotmilan is also doing excellent bank and yank turns, very aggressively, where some other place doesn't like it. Energy management turns or half roll half loop turn are also possible. The turn technique will of course give different result depending of the slope, the edge, the wind speed, etc ...

In medium to strong condition, as soon as it reach it's flight regime, the Rotmilan retains its energy very well, and can bank and yank hardly with an excellent exit speed. HN sections are know to be optimized without the extensive use of flap to change the camber. Therefore the amount of snapflap must be low otherwise the plane slow down in turn. I found a good compromise with a CoG at 106mm.

Compared to his larger brother the standard Rotmilan, the Rotmilan Midi is more agile and can be flown more aggressively. I also found that it turns better with a bit more grip, thanks to the equivalent tail for a shorter wingspan and shorter fuselage.

My Settings
  • CoG: 106 mm from the leading edge
  • Elevator: 6 mm Up / 6mm Down
  • Rudder: 10 mm Up / 10 mm Down
  • Ailerons (measured at the intersection between flaps and ailerons)
- Ailerons: 30 mm Up / 15mm Down
        - Flaps: 15 mm Up / 5mm Down
  • Snapflaps(measured at the intersection between flaps and ailerons)
- Ailerons: 6mm Down
        - Flaps: Aligned
  • Camber -  thermal position (measured at root)
- Flaps: 5 mm Down
- Ailerons: aligned
  •    Camber - speed position (measured at root)
        - Flaps: 1mm Up
- Ailerons: aligned
  • Butterfly  (measured at the intersection between flaps and ailerons)
- Ailerons: 10 mm Up
        - Flaps: 40mm Down
- Elevator compensation: 4mm down

To conclude, The Rotmilan Midi bring some improvements compared to the standard version, mainly agility at the ailerons and a bit more grip in turn. It remains a very affordable and still competitive F3F plane, with a superb moulding quality.

Hereafter are 2 videos I did in October and November:



Sunday, November 23, 2014

Breaking news: New DS world record at 813 km/h !!!



The 800 km/h barrier has been broken by Bruce Tebo flying his Kinetic 130 at Weldon (California) the 22th of November. After a first flight at 503 mph, Bruce improved it with 505 mph (813 km/h). For information, he doesn't use any gyro in his plane.









Saturday, November 22, 2014

Fresh air and some snow !




This afternoon, I went to col de Faisses again despite some snow falls the previous days. The ride to the top was a bit difficult because of the snow, even with a 4 wheels drive, certainly because of the summer tires. Temperature was cool, about 8 degrees, and conditions smooth, with around 6 to 8 m/s. I was alone adn had the entire slope for me :) !


I used the mobius action cam in photo mode, and timelapse to take to onboard picture with the cam attached at the wing tip. I also did some video with the mobius and also the GoPro on the ground.


Friday, November 21, 2014

Zepsus Magnetic BEC

Life, Lipo or more recent Li Ion receiver batteries are usually in 2S so deliver high voltage. However some servos released few years ago have not been designed to support high voltage and can at least reduce their lifetime when used with high voltage, or even can burn. Zepsus, well know for the magnetic switch that became very popular all around the world and equiping lots of F3X glider, recently released a new magnetic switch that includes a voltage regulator.

This Magnetic BEC features an impressive 14A max output current, operates with a 3 volts to 10 volts input voltage, is configurable to deliver 5, 5.5 or 6V output. It is compatible with all chemistry, from a 5S NiMh or NiCd to the more and more used 2S LiPo, LiFe, LiIon. The big advantage of the Lixx chemistry is that they can deliver higher current corresponding to the very demanding modern servos. The voltage regulation is linear, so what I would call RF friendly (ultra low RF noise) at the opposite of the usual U-BEC that can create problem with the receiver depending of the installation. 

Zepsus magnetic BEC is deliver in a small plastic bag with a small magnet and 2 stickers to install on the fuselage to indicate where to apply the magnet to switch on and off the magnetic BEC. It has a dimension of 59 x 26 x 5mm, and has a radiator face to dissipate the heat if needed.



The quality of the Zepsus Magnetic BEC is really nice with silicone JR type extension on the receiver side (2 times 0.5mm2 section). It has 2 connectors to provide some redundancy, but first to allow higher current. On the battery side, it is also large silicone wires (1 mm2 section). I installed a JST connector (crimped) to be compatible with the batteries I uses. On one side you have a jumper allowing to select the output voltage you want. When ON, a bright green LED allow to see the state of the switch. It is so bright that you can possibly see it through the nose cone. A small magnet is provided, but I recommend to use a bigger and stronger magnet like the Jeti magnet. It eases operation greatly from my point of view.

So if you have gliders with LV servos but you still want to migrate to HV batteries that provide higher capacity, low self discharge, higher max current, this Magnetic BEC is definitively the way to go. For small plane there is an smaller version of the magnetic switch delivering 5A, and with a single connection the receiver. I have 4 or 5 Zepsus switches in my competition planes that I uses for several years and I'm very statisfied by the quality and reliability of them. It is so convenient to close and tape the nosecone at the beginning of the day and switch on and off easily with the magnet that I couldn't return to a mechanical switch ! I definitively recommend Zepsus switches and this new magnetic BEC as Zepsus's owner (jesper Christensen) is also a F3F pilot and competitor so he knows what he is talking about !

Magnetic BEC Specifications

  • Input voltage range: 3~10V
  • Designed for 2s Lipo/Liion/LiFe or 5s NiMH/NiCD batteries
  • Output voltage choice: 5,0V/5,5V/6,0V
  • Output current continuously: 14A
  • Output current burst: >30A
  • Ultra low stand-by current: 6µA (micro-ampere)
  • Max power loss continuously: 8 Watt
  • Max power loss burst: >40 Watt
  • Ultra low dropout voltage: 63mV@8A
  • Connectors: JR-type “Double connector to receiver”
  • Wire: high-quality 1mm2 and 2×0.5mm2
  • Weight including cables: 14.5grams
  • Length including cables: 19cm
  • Dimensions including heat shrink: 59 x 26 x 5mm
  • Operational temperature range: -40C to +125C



Wednesday, November 12, 2014

[Movie] Interstellar

Seen on RCgroups:

The opening sequence of the movie INTERSTELLAR with an indian drone flying alone over the fields was done using a 33% scale Predatorish miniature, 5.5 meters wingspan, weight from 10kg, powered by  a Neu propulsion sytems. The group of south california soaring modelers composed of Larry Jolly, Ben Clerx, James Turner, Dennis Brandt, Dean McCoy, Chris Jolly, and Anya Ellis all pitched in, and helped get things done in time..

For information, Larry also participated to the movie Armagedon, and plenty of other nice project in Hollywood !

The full story can be read here

Interstellar is a super movie from Christopher Nolan, with a nice story (A group of explorers use a newly discovered wormhole to surpass the limitations on human space travel and conquer an interstellar endeavor.), excellent actors, superb visual effects. It lasts almost 3 hours, but the time passes very quickly. I really recommend it !




Tuesday, November 11, 2014

3D printed radio installation

Today, I could see a very nice radio installation in a Electro Alpina 4001. All the different part have been 3D printed. The servo tray use an inner honeycomb structure. the propulsion battery support can move to change the center of gravity. The orange box host the receiver and the power switch. I have no picture, but the servos covers were also 3D printed. All parts uses PLA material and are made on a printer having a volume of 20cm x 20cm by 15cm for the height. The result is very neat and clean as you can see on the pictures.


Monday, November 10, 2014

2 new color schemes for the Vagabond

2 new color schemes for the Vagabond from Hacker Model. The honeycomb is very popular now ;) !

VV Stinger

While the Stinger 2 is about to be released soon, here are pictures about the kit of the Stinger. This one is not belonging to me, but stayed at home for few days before to be delivered to his happy owner.


Col de Faisses

Some pictures taken at col de Faisses the 1st of november. My F3F planes stayed in the car and I flew only my Weasel Black Edition. Other planes were mostly powered as the conditions were very light. Still a nice and cool afternoon with a super light for pictures.


2 weeks before, I had another session there where I could meet some pilots from Lyon area. Conditions were much better.


Aerial pictures: Castle of Bon Repos

While some stupid people are flying with drones over french nuclear power plants, there are many better things to do with a quadricopter like photographying the Castle of Bon Repos near Grenoble. The Quad is aTBS discovery and the cam is the GoPro3 black edition in timelapse mode. From the 580 pictures taken, I selected only 33 to create this photo album.


Zepsus Magnetic BEC

Zepsus just released a new product called "Magnetic BEC", which combines a magnetic Switch and a 5-6V linear voltage regulator. It allows to power a F3x glider equiped with Low Voltage servos from a 2S Life/Lipo/LiIon battery. It is available in 2 versions: 14A for F3x plane and 5A for HLG gliders. Given the excellent quality of Zepsus products (I have 5 Zepsus magnetic switches in my F3F planes), there is no doubt that this new Magnetic BEC will be a best seller !

More info at http://zepsus.com/


Wednesday, November 5, 2014

Rotmilan Midi Assembly


Note: you can read the first part here: kit overview

The rotmilan doesn't reserve any real surpise during the assembly. There are however some particular points to to take care so I will develop. On the fuselage, the most delicate operation is the wire routing from the front of the fuselage to the green plug print location. Because of the bassat tube already in place, there is very little remaininf space on each side to route the 4 wires. They must be under the ballast tube, then go on the side to reach the wing plug hole. Here is the technic I used. I prepared the servo wires, around 45 cm long (the standard 30cm servo wires is too short). then using a thin piano wire (0.8mm) or a thin plastic sleeve, I passed it from the joiner location to the fron of the fuselage, then taped the wire extremity to it, and pull carefully until the wire exits. You need to do it 4 times (2 on each side), given that the second wire has even less space since the firt one is in place. Doing like this, it is not painful, but still requires some patience. The plug holes doesn't have recess to block the plug in place. I created it by gluing a 1mm plywood piece going from one plug print to the other, top and bottom. Once done, yuou can exit the wires, sloder them on the green plug, protect the soldering with hot gun glue and glue them in place with rapid epoxy.
On the rear side of the fuselage,



I used MPjet brass threaded coupler. There were with a 1.3mm, so I drilled to 1.5mm. The linkage provided has a layer of teflon that you need to remove first. The core of the linkage is fiberglass. I glued the coupler on it with some rapid epoxy, and crimped twice (at 90°) to secure it totally. To finish I glued the metal clevise on it to suppress any slop. The rear end of the linkage being done, I connect them to the tailplanes. I neede to sand the inner side of the fuselage to gain some space and allow the clevise to move freely. I also cut the recess that receive the end cap, and milled the end cap to allow the elevator horns to move. The result is very clean, simple and nice. No slope, free moving nice fit and junction of the parts together. This is obviously well designed and moulded.

Let's continue with the elevator servos. The tray is designed to receive 12mm servos like the MKS 6125e or equivalent. The hole is at the right size to not damage the wire when inserting the servos in its location. Here again, I used brass MPjet coupler after cutting the linkage at the right length. I then installed plastic MPjet (with metal axis) on them to have a tight mounting without any slop.

We can then start the wing servos installation. I used 2 MKS 6125 mini at the ailerons, and 2 MKS 6125 glider at the flap. As I said in the overview, the LDS is factory installed on the control surface, and is removable which is clearly a plus for any maintenance, or for the installation. for this a tool is provided. This is a long brass rod with a threated hole at one extremity. The LDS axis hae also a threated end. From the root of the wing, it is easy to screw the axis, then pull to extract it or push to install it. This is really well designed !


The linkages are epoxy board arms, the short ones being for the ailerons, and the long arms for the flaps.
On the servos side, after putting 2 extra layers of 93g/dm2 carbon fabric to avoid any deformation of the skin once the servo is installed, I sanded the surface, glued in place the wood servo frame. Make the operation carefully as the likage, LDS, servo head is mounted tighly and that any deviation will create friction or blocking point, so the servos will not work properly and the return to the neutral position won't be accurate. There are 2 servo head types: one with the hole at 5mm from the center which is for the ailerons, and one at 6mm which is for the flaps.

Once in place, I added a S-BEC in front of each servo as I use 2S LiIon battery, so high voltage. The wire extension done, I glue the green plug in the wing with the wing mounted and connected to the fuselage, and using some PVA release agent everywhere it is needed, in addition to some thin tape to protect the fuselage or the root of the wing. The flat servos covers are finally cut a the right dimension (there is a thin line to indicate where to cut) and taped in place.

Let's finish with the battery installation, and balance lead melting. As I said, the battery is a 2S LiIOn 18650 cell format, providing 2900 mAh. Once in place, the receiver takes place on top, with some plastic sleeve to guide the antennas. I needed 150g of lead to do the balance for a CoG at 106mm.

Finished component weight are the following:

  •     Left wing: 692gr
  •     Right Wing: 690gr
  •     Fuselage: 742gr
  •     Wing Joiner: 88g
  •     Left tail+ joiner: 40g
  •     Right tail + joiner: 42g

    Total 2294gr

French F3F League

Hereafter are some pictures of the 2 last contests of the french league. First of all the Vosges 2 contest beginning of October, where ae flew on Staurday in very variable an light conditions on the south west slope. Aubry Gabanon won the competition on his FS 4.3, taking a good option on the league victory. He is followed by Arnaud Leger (Pike Precision) and Elian buchholtz (Arsen).



Last contest of the french league was the week after in Laurac. After 12 rounds and an hard battle between Aubry Gabanon (FS 4.3) and myself (Shinto and Pike Precision slim), I missed the contest victory by 4 points over 1000 at the last round, and as consequence, the french league winning by 9 points (over 4000). Aubry deserved his victory as he piloted very well and did no mistake. congratulations to him ! Sébastien Lanes (Target and Stinger) is finishing in 3rd position of the contest after a very good climb the second day. JB Deguelle is 4th and Frederic Hours is 5th. A great contest, with good weather, good wind despite sometimes crossed, some thermals. Friendly people on the slope and good ffod in the south west of France, in brief a good week-end to close the season. Hereafter are some pictures taken this week-end.



Below the final league results (70 participants):


Real size gliding at Saint Eynard

Last sunday afternoon, I went to the Mont Saint Eynard, above Grenoble to see real size glider doing slope soaring along the cliff. Impressive, especially the noise. Few days ago I was in the plane (Taurus), this time I was on the ground. It was mainly ASK13, but I saw also a duo discus. Nice moment !


F3F Season ended

F3F season 2014 is finished for me. It has been a great season with nice results:

- Team world champion  in Donovaly (F3f WC)
- 5th in individual at the same F3F worlds
- 4th at the Eurotour, only 0.07 points from the podium !
- National F3F champion 2014 (7 titles)
- Second of the french F3F league
- New personnal best time with 28.01s (Needle 100 DSL)
- 1 worldcup/Eurotour contest victory at Col de Tende

I would like to warmly thanks my sponsors MKS and JR. DMSS 2.4 is rock solid and new MKS HV servos are just incredible. The HBL 6625 is for me the best wing servo ever ! With the new HBL 6625 mini, the 6125e HV and the 6100 HV, without forgetting the 737 HV and the 747 HV, the family is now large and provide a solution to each situation.


Thursday, October 16, 2014

Rotmilan Midi, kit overview



This is the shorter version of the Rotmilan which just won the F3F WC 2014 in František Ruisl's hands. With a wingspan of 2.86m and length of 1.47m, it features the same HN section than the Standard Rotmilan, It is made by RTGmodel (Website not updated yet with the Rotmilan Midi). I received my Rotmilan Midi in Donovaly when I was there for the F3F world championship. The color scheme is mine and based on the constraint that the control surfaces are moulded with an angle to allow the moulding of the wipers at once.

Let's have a look to the kit. Fuselage is made from Kevlar and Carbon. It is 2.4 friendly as the front part is kevlar only. The ballast tube and the servo tray, as a single piece is already installed in the fuselage. The tray is designed to receive 12mm standard servos like the MKS 6125e or equivalent. The hole is at the right size to not damage the wire when inserting the servos in its location.

Canopy is fiber glass with the lock system already in place.

The ballast tube occupies lot of place in the fuselage so the routing of the wires from the wing connectors to the receivers is pretty tricky. It requires to solder the green plug with the wires in place.

The elevator control rods are snakes using fiberglass core and teflon sleeve. They are guided into a plastic sleeve. No clevises or couplers are provided. In brief, the fuselage requires very little work.

The tailplanes are identical to the standard version and include the carbon rod joiners. 2 metal pins are here also for a better positionning. They still use the very simple and efficient aluminium control horns to be connected to a metal clevis

Wings are simple carbon using herex and spread tow fabric. The servos holes are reinforced with some extra carbon to avoid skin deformation while installing the servos frame. There is no ballast compartiment in the wings. The large carbon joiner allows to use brass ballast in it (not provided), to be added to the 900g of fuselage ballast provided with the kit (10 slugs).

RTGmodel has been the first manufacturer to use RDH/LDS. As it is built in, the installation on the control surface side is finished, and removable using a tool provided in the kit, a long brass rod that allow to extract/put the RDH axis from the root chord.

What to say about the moulding and finish quality. The Rotmilan moulding quality is absolutely top notch. Fit and finish are just superb: The illustration is how the joiner fit in the wings and the fuselage. no blocking point and no slop at all. When removing the joiner, you ear the "pop" sound.

To finish with the kit overview, here are the component weight:
  •     Fuselage: 387g
  •     Right Wing: 586g
  •     Left wing: 592g
  •     Wing Joiner: 88g
  •     Left tail+ joiner: 40g
  •     Right tail + joiner: 42g
  •     Total 1735g
  •     Ballast provided: 892g


Wednesday, October 15, 2014

Font D'urle 2014, the french longpan slope !

Font D'urle 2014 will remain in the memories for a long long time. The reason is that conditions were super fast and that the french F3F record has been beated several times in few minutes, by different pilots. The contest took place on a high cliff in the south vercors (french alps) with strong wind (14 to 16 m/s vertical). We have the authorization to fly there only once a year, and were are accompagnied by an eco-guard to check that vultures living there are not disturbed by the gliders.
On sunday, the wind was so strong that we had to stop the contest after two rounds, because almost all pilots damaged their plane during the landing in a huge rotor, despite walking far from the edge to escape this rotor. With 27.28 seconds, Frédéric Hours established a new french F3F record flying an Alliaj HM (in fact the early prototype of Alexis Maréchal). Jean-Luc Foucher and Allan Cohen joined the 27.xx club, both also on Alliaj HM. Personnaly, I achieve my personnal best with 28,01s with my Needle 100 DSL.



Below the video of the record:


Icare Model show 2014

The 20 and 21th of september.

The now famous and popular Icare Model show (Coupe Icare) is since few year having also an aeromodelling show where it is possible to see all type of aeroplanes from the drone to the big aerobatic plane, etc ... Weather was not exceptionnal this year but we could however do many demonstrations from 10am  to 4pm. Less spectators because of the weather. Here is my photo album shooted on sunday

The Beaufortain, Savoie

End of september, I visited another slope paradise (Beaufortain, Savoie) not very far from Grenoble. I took only my Weasel and flew 5 minutes at le Cormet de Roselend. There are plenty of slopes in the area and some of them have the Mont blanc in background. If you add to this the fact that the beaufort cheese (http://en.wikipedia.org/wiki/Beaufort_cheese) is produced there ... yum yum ...
A very nice place to go with stunning landscapes as you can see on this photo album !

Flying over Grenoble

I had the chance to enjoy a flight but also pilot few minutes a Taurus from Pipistrel (World’s first side-by-side ultralight powered glider). We did some slope soaring on a cliff above Grenoble. A 1 hour flight in excellent conditions, ended by a smooth kiss landing at Le Versoud airfield. Thanks to Olivier Finck (http://www.airtech-rc.com/) for this flight !


 

Saturday, September 20, 2014

Pikes Slim radio installation and maiden flight


Installation is (very) tight, but fine as after some thinking, each element finds its place naturally.
Some changes however: I installed the super tiny and powefull MKS DS6100 for the elevator (note: The MKS DS6125e can fit).  I replace the 8 channels receivers by a 6 channels receiver, installed on top of the fuselage. The battery is a 2S LiIon 2900 mAh, so I have S-BEC in front of each servo. Satellite is in the nose. First antenna is below the receiver, in a plastic sleeve glued in the fuselage, the second antenna is on the side of the receiver with an angle of 45 to 60° (not 90° as idealy recommended).



At the end I needed about 130g of lead in the nose to retrieve my optimal CoG of 107mm. I will keep my current settings as the rear boom has the same length. Empty weight is 2170g for a double carbon ST wing version, which is a very good weight for F3F.

Maiden flight occured end of august, few days before my departure for the World championship on Slovakia. Conditions were light and it was difficult to say if there is a small of big improvement over the standard fuselage. Only time will says, with competitions and a panel of conditions. It seems however that the plane is a bit more pitchy which would indicate a lighter fuselage moment because of the shorter nose.For the rest, it is very subjective to write any conclusion.

Below is the video of the maiden flight at Puy de Manse:



Report: Alpine F3F cup, Briancon


1 weeks after the FAI of col de Tende (eurotour/worldcup), most of the pilots met again in the french alps in Briançon for a contest of the Eurotour. the specificity of this contet is that we reach the slope using 4x4 cars therefore the number of participants is limited to 30. This year, I have been honored by the organisers to be responsible to drive one of the 4X4 cars. This is my first experience ever, and I really enjoyed it, with my copilot Mickael Krebs. The first day os the competition we went to the south slope, waited a bit for the breeze to install, then started some rounds. Conditions were very variables from one flight to another. At the end of the day, we had 4 rounds in the pocket. Matthieu Mervelet was in first position, followed by Frédéric Hours and Stephane Riccobono. On Saturday, we changed to the North slope located at 2400m of altitude. The wind was blowing strongly so we could expect lots of additional rounds and a change in the ranking. This slope is very technical and challenging. Gain of altitude during the 30 second was very important so pilots were flying along the rocks and cliff on the right and wait until the maximum before to start. Then the best strategy was to do bank and yank turns and manage some diving, keeping in mind the antidiving rule of 5 seconds. At this game, Stephane Riccobono has been the best, well served by his Stinger that was flying great and super fast, like all stingers this day. The landing area was fine, but needed some attention, some some plane has been damaged. We saw also 3 spectacular crashes on the slope with 2 plane totally destroyed. Saturday evening, the counter was at 11 rounds, Matthieu dropped down in the ranking, Stephane was now first followed by Sébastien Lanes and Fréderic Hours. Monday, despite very encouraging forecasts, has been very disapointing as we got no wind so didn't do any round, and the ranking became the final ranking.

Overall a super competition, very friendly, in a superb place with a nice ride in 4x4. A great thanks to Alain Gallinet and Frederic Hours for organising it !



I have made the following video to capture the atmosphere of this contest. I think it tells a lot about it:



Flying the Vagabond from Hacker Model

I programmed several flight modes with different amount of elevator. Normal flying with normal (but still agile) elevator, full elevator position with lots of exponentional to keep the Vagabond controlable and a thermal position with some camber and little elevator mouvement. Despite this, the Vagabond needs an adaptation time. It reminds a very agile plane, without inertia, and very neutral which needs always some attention to pilot. It is possible to fly the Vagabond in small conditions and thermals with it. Now don't expect to do long transition to catch the thermal. I you go through sink air, the plane will show it clearly and loose altitude quickly. At the opposite, I flew the Vagabond in strong and turbulent wind. The structure is flexing in all direction, but the plane remains controlable. Now this is not fun and there is no means to ballast it. No, the best conditions for the Vagabond are a gentle breeze creating a stable lift at the edge. Here everything becomes possible and you enter in a new dimension of the flight. Roll, reversal, looping, flip, inverted flight, knife edge flight, stall roll, all combination of them, plus new manoeuvers that you can create.



We haven't noticed much differences in flight between the light version (not covered and 500g) and the heavy version (610g). This is why I recommend the covered version that will improve the lifetime greatly.
Have an eye on the battery consumption because the 4 servos and big control surfaces drain the battery quickly, and as the plane is addictive and that you cannot stop, you could easily drain all the battery power :)

Finaly, Hacker suceeded to proposed a VTPR plane that requires a short assembly time, with a nice looking and that have the main characteristics of a VTPR plane, bringing lots of fun and joy to its pilot. For me the goal is perfectly achieved even if the purists will find some negative points.

Below are 2 videos made this summer of the vagabond. First one is at le col du Glandon is a strong and turbulent wind. The second one is at le col de Tende in ideal conditions.

Flying the Vagabond from Pierre Rondel on Vimeo.

 
Enjoying the Vagabond from Pierre Rondel on Vimeo.

Wednesday, September 17, 2014

Report: FAI Col de Tende

The 18th, 19th and 20th of July was the first edition of the FAI contest of the Col de Tende at the border between Italy and France. In fact this contest was formerly the contest held in Caussols, but organisers decided to move it to Tende to use this exceptional slope with good breeze conditions in summer. For this first edition, plenty different nations were represented among the 32 competitors coming from France, Germany, UK, Poland, Cezch Republic, Switzerland, Netherland, Austria.

Friday, after the briefing at the end of the morning, we could complete 2 rounds, the third one couldn't be validated because of too many reflies and also because of the wind dying

Saturday was a great day as we could fly 8 rounds. Conditions has been very stable as expected. Only the clouds appearing time to time because of the pressure and humidity had to be carefuly followed.

Sunday, we could add 4 more rounds to reach a total 14 rounds. Unfortunately, it was 1 round less than the number required to active a second joker. Anyway, it was a great competition organized by Paul Eytan and Allan Cohen. We all get a bottle of Limoncello :) !!!

For me it was my first competition with the Shinto. After 14 rounds over 3 days, I won the competition by a good margin. The Shinto worked great, from small conditions to strong conditions. I flew up to 1.1 kg of ballast because the high altitude and the low air density. My best time over the week-end was 2 times 34 seconds. At the last flight, I almost atomished my plane on a big rock while pumping to gain altitude. Hopefully for me, I avoided the rock by 30cm. 

MKS servos HBL6625 and HV6125e worked great, in association with the LDS from Aerotec. I always have an observation periode when having a new plane to "secure" it, see what must be modified, or tuned. At the moment, everything is perfect. 





Video: Needle 115V onboard cam

A flying session at puy de manse with a Mobius attached on the wing tip or on the fuselage:


Video: New launch method !!!

Michel Leroyer launching ... well pushing Gérard Prat's Air 100 into the slope. We had about 70km/h of wind at that time


Video: Asw-15 aerobatics

Roland Stuck doing aerobatics with his home made 5 meters wingspan ASW15. A super pilot and a nice plane for a magic moment.



Picture of the 16th of July

A 4 meter Air100 doing aerobatics at Corps, near Grenoble.


V-Venture, le prêt à voler selon Graupner



Introduction

Le V-Venture est le petit nouveau de Graupner sur le segment des moto-planeurs de début avec moteur propulsif. Il rejoint le Rookie vendu par la même société. Il vise davantage le jeune débutant pressé de voler et ne voulant pas s'embarrasser avec la construction. Il est du coup disponible uniquement en version  RTF, livrée avec un émetteur MX10 ou en version RFH qui signifie «ready for Hott» le système 2.4ghz commercialisé par Graupner. C'est cette deuxième version que je vous propose à l'essai aujourd'hui.

Présentation du kit

Le V-Venture arrive dans une large boite, bien calé dans son fond de boite en polystyrène.
Ce qui attire immédiatement l'attention, c'est ce stab en V déjà assemblé, non démontable et ne fournissant que la fonction profondeur. Ce choix de conception est de prime abord curieux et prend à contre pied les modèles de débuts traditionnels «dérive-profondeur». Nous verrons lors des essais en vol si ce choix est finalement judicieux ou non. Le fuselage est entouré par les ailes posées sur la tranche.



Une notice de 9 pages est fournie avec le kit. A mon goût, elle contient un peu trop de texte et pas assez de schéma simple et clair, donc elle demande un peu plus d'attention pour suivre et comprendre les quelques étapes du montage et réglages, un point à améliorer.

Le fuselage est complètement terminé, décoration posée, verrière peinte en noir, fermant à l'aide d'un aimant à l'avant. L'unique servos de profondeur (un DES 281BB MG) est situé au fond du fuselage. Devant se trouve le récepteur GR-12 Hott déjà câblé. Petit soucis du détail, un bout de gaine collé verticalement permet de bien positionné le brin d'antenne de manière idéale, on apprécie!

Le fuselage est rigidifié en son centre par un tube carbone. Le moteur Compact 260 7,4V est fixé à l'extérieur, garantissant un bon refroidissement. Le contrôleur ESC de 18 Amp est dissimulé derrière
la verrière à la base du pylône moteur. Il est facile à retirer si besoin.

Les ailes sont également prêtes à l'emploi: elles sont équipées de servos DES 261BB, servos numérique sur roulement de la classes des 11gr. Là aussi c'est un bon point. Le montage permet des débattement mécaniques conséquent ce qui permettra par programmation de l’émetteur de satisfaire tous les pilotes, du parfait débutant au pilote dégrossi désirant un planeur plus maniable.

La décoration est déjà posée sur l'ensemble du modèle. A la sortie de la boite, elle est du plus bel effet. Il s'agit de décalcomanie extrêmement fin, probablement posés à l'eau comme sur les maquettes de ma jeunesse (maintenant lointaine). L'avantage est que la décoration épouse parfaitement les formes même non développable du planeur. Elle est de plus bien visible et offre un bon contraste.

Le V-Venture est livré avec un accus Lipo 2S de 2500 mAh avec une prise JST. Il faudra d'ailleurs prévoir une prise d'équilibrage Graupner si vous n'en avez pas encore.

Montage ... vous avez dit montage?

Et bien non, rien à faire, puisque même le récepteur est branché. Il suffira donc de chargé l’accu de propulsion et de la placer dans le fuselage. Il se loge pile poil, bien calé à l'avant du fuselage, sans risque de se déplacer en vol.

J'ai trouvé le montage soigné, aidé par une conception simple et très rationnelle. J'ai juste rajouté un bout de blenderm à l'intrados pour empêcher les fils de servos d'ailerons de sortir de leur saignée. Petite parenthèse: Le blenderm de 3M se trouve en pharmacie et est l'adhésif idéal pour les modèle en mousse. Son accroche est meilleure et sa souplesse permet d'optimiser sa tenue.

Les ailes s’emboîtent fermement l'une dans l'autre grâce à une découpe façon puzzle. Le maintient est excellent. La clé d'aile est un tube carbone de 10 mm de diamètre extérieur.

Par contre la connexion des servos d'ailerons sur le récepteur est peu pratique à l'usage, car aucune rallonge n'est fournie obligeant à chaque fois d'enlever l’accu de propulsion puis de sortir le récepteur de son logement pour y brancher les servos. Ceci étant dit, le V-Venture est compact donc on peut se permettre de le laisser monté la plupart du temps.

Bien que le centrage soit indiqué dans la notice, et que le modèle soit centré correctement avec la batterie de propulsion fournie, j'aurai aimé une petite marque de moulage comme cela se fait généralement pour bien identifier le Centre de Gravité. Ce ne coûte rien et c'est très formateur pour un débutant de vérifier l'équilibrage avant le vol.

Le réglage de la radio est un jeu d'enfant. Vous pourrez prévoir un dual rate pour les ailerons. La notice recommande également le réglage de ce qu'ils appellent «speed brake» en relevant les ailerons vers le haut. Bon allons voir maintenant ce que cela donne en vol!


Essai en vol

C'est sans inquiétude aucune que je suis allé effectuer le premier vol dans un champ non loin de chez moi. Petit contrôle du centrage et des commandes et c'est parti!

Mise en route du moteur, le V-Venture part tout droit sous une pente douce. Le moteur n'est pas un foudre de guerre mais suffit a monter gentiment le modèle. Par contre il est clair que la motorisation a été calculée au plus juste, et l'on ne pourra pas rajouter de charge supplémentaire comme par exemple une petite caméra.

J'ai été tout de suite surpris par la docilité et la stabilité des trajectoires. Le double, voir triple dièdre, en est la raison. Les ailerons sont doux, sans être pour autant mous. Contrairement à un 2 axes dérive-profondeur où l'on doit maintenir l'ordre à la dérive, ici on incline aux ailerons puis on relâche et on soutient légèrement à la profondeur. J'avoue avoir été un peu dérouté au début par l'absence de dérive, mais on fini par s'y faire. Le V-Venture fait preuve d'une certaine auto-stabilité sur l'axe du roulis: S'il est légèrement incliné et qu'on laisse les manches au neutre, il revient doucement à plat. C'est une caractéristique intéressante pour un débutant. De même, le décrochage est tardif et tout gentil, une autre qualité d'un planeur de début.



Malgré un profil annoncé sur le papier comme étant un HQ 3/12, on ne peux pas dire que le V-Venture soit un moto-planeur fin, cela étant due à sa faible charge alaire, qui est à la fois un atout et un handicap. Certes, il marque bien les changements de portance, mais malheureusement ne permet pas de s’échapper facilement  d'une zone de déportance. Moteur arrêté, l'hélice ne traîne pas trop et on se laisse prendre au jeu à enrouler les petites bulles de passage.

Le V-Venture ne rechigne pas à remuer un peu. Il passe la voltige de base, en s'aidant du moteur pour compenser la faible charge alaire et donc le manque d'amplitude des figures verticales. Le tonneau est plutôt bien axé, le vol dos avec moteur peut durer longtemps, preuve d'un calage aile/stab/moteur bien calculé

Gros point noir à l'usage, la déco s’abîme vite partant par petit bout sur les éléments exposés et sollicité. Je vous conseille de prévoir un marqueur permanent noir et rouge pour faire des retouches afin de garder la décoration dans un état correcte.

L'atterrissage même sans les aérofreins ne pose aucun problème. Le V-Venture se ralenti sans aucun problème permettant d'envisager des posés très court si nécessaire.

Coté autonomie, excellent surprise car en fonction de l'usage moteur, on oscille entre 20  et 30 minutes, voir beaucoup plus si les conditions s'y prêtent. Ceci n'est pas surprenant à la vue du choix de la motorisation en 2S et de la tension nominale du moteur à 7.4v.

Conclusion

Bien que surprenant dans ses choix de conception, le V-Venture  remplit parfaitement son contrat. Il constitue un bon modèle de début, avec peu d'inertie, donc plutôt résistant  aux chocs. Équipé d'éléments radio/moteur de qualité, son montage est soigné, sa docilité et stabilité en vol en sont ses atouts. Et puis son autonomie moteur est excellente. On regrettera juste que la jolie décoration soit si fragile à l'usage.


J'ai aimé:
  • Conception rationnelle et montage soigné
  • Très stable et docile
  • Excellente autonomie moteur
J'ai moins aimé:
  • Décalcomanies très fragiles
  • Stabilisateur en V non démontables
  • Pas de marquage du CG à l'intrados de l'aile
Caractéristiques techniques
  • Envergure 1350 mm
  • Longueur 860  mm
  • Poids du modèle testé 535  g
  • Surface totale 26,7  dm²
  • Surface du stabilisateur 5,0  dm²
  • Surface des ailes 21,7  dm²
  • Cordes 19/18/12 cm
  • Profil de la profondeur NACA 009
  • Profil de l'aile HQ 3,0/12
  • Charge alaire 20  g/dm²


Planet-Soaring is back













Hello  all!

After a summer break, planet-soaring is back with plenty of work on the table. I just returned from the F3F world championship in slovakia where I got a team gold medal with my team mates ! the week before, I also kept my national champion title in Ardèche on a super spot. We did 20 rounds in 2 days with plenty of fast time and a sub-30 (29.40s) for me which is not so often. Erlier in the summer I broke my personnal best in the vercors with a 28.01s. I also won the eurotour/world cup contest of the col de tende on the France/Italy border. In brief, a very sucessfull summer with plenty of nice memories, and pictures that I will share with you in the coming days !

Stay tuned !

 




Thursday, August 28, 2014

On the road !

The french national F3F team will be on the road from tomorrow until the 15th of September, starting by the national championship in Ardèche during 3 days, followed by a world cup contest then the world chammpionship in Donovaly (Slovakia). We will try to post update and pictures daily on our blog, so feel free to visit us often and let a message !


Tuesday, July 8, 2014

New Pike Precision Slim fuselage

Samba Model is releasing a new slim fuselage for the Pike Precision. Philip Kolb, one of the designer says about this new fuselage:

"As we are always interested in areas of improvement on our planes we are especially intriegued to save drag - especially on fast flying aircraft like the Pike Precision.
Honestly it is very difficult to reduce drag on the wings' sections as the wing needs to operate within a wide variety of lift coefficients. Reducing airfoildrag at low lift coefficients and high Reynolds numbers - so to say at high speed - will almost certainly result in worse performance in other flight phases than speed.
One easy area of improvement though is to reduce the surface of the fuselage. The latest state of the art equipment (batteries, recievers and servos even became smaller than before and thereby allow to reduce the length and diameter of the fuselage nose. This reduction will mainly result in a reduction of inertia, as the nose can be shortened to some extend.
Higher modulus carbonfibre and spreadtow technology allow for a reduction in diameter, especially on the tailboom, where the airflow is fully turbulent and thereby very draggy compared to all the other parts of the glider.
We tried to implement this considerations in the new fuselage design making it even more slim and sleek than its predecessor. The structural buildup is certainly a challenge, but managable with modern fibre technology. The aerodynamic gains will be noticeable and result in better highspeed - and turning-performance."

The new fuselage is 38mm shorter on the front, slimmer everywhere, nose, boom, root, needs obviously a new joiner, and can receive previous tailplanes with light adaptation of the elevator arms. Jane sent me the following pictures to give you a better idea.



Vagabond assembly

The Vagabond is ready ! It weights 620g. Overall, the assembly went well, the design for an EPP glider is pretty good. I started by the fuselage and carbon rods to stiffen the boom. Then I also installed the elevator and rudder control rod sleeves. Be careful to not bend them while installing them into the foam because when bent they can make the mouvement of the rod less smooth and bad neutral position return. The servo tray is glued on the EPP using fluid cyano. Once done, I focused of the tailplane, that I wanted absolutely to make removable. My first idea, what to modify the joiner extremity (4mm carbon rod) to lock it in rotation with a corresponding print. Problem was that I still could twist the tail because of the rod torsion. My clubmate Joel Marin, who build a Vagabond too, found a clever and simple solution for the tail: use a small aluminium tube at the root, and drill a small hole in the tube and the carbon rod to install a stop pin. The pin have a L shape to secure it with some tape. As final solution, in addition to the aluminium tube, I added on both side of the tail a small epoxy plate to improve guidance. Now, it is fine, the tail is perfectly secured in rotation and translation.

Remaining task mainily consists in the radio installation. I used 9gr, metal gears in the wings, a 13mm old analog but strong servo for elevator, and a tiny plastic gears 9g servo for the rudder, which is a bad idea as I quickly broke the gear. To metal gear everywhere is my recommendation.
Initially I wanted to use a 4cells 2 A eneloop battery, but it is clearly too heavy, even if there is plenty of space in the nose front. I finally installed a 4cells 800mA eneloop battery. I didn't need any lead to achive the 100mm CoG. Flying weight is 620g. For comparison, the uncovered version of the Vagabond is 500g, so 120g less.

Please find below the assembly log photo album that tells more that hundreds of words !


Nice video using a Drone

A superb video from Thibaud, using his TBS Discovery Pro.


How to make very inexpensive 2.4 ghz antenna sleeves

I use a cotton bud (Q-tip) that I cut to keep the center part. Diameter is perfect for 2.4 Ghz antenna, even with shrink tube around. Then I put some hot glue on one side to block the antenna. In the fuselage I glue one guide with cyano. For the second antenna, I let it free but use a piece of coroplast to position it correctly (vetically), along the receiver. The cost ? 500 cotton bud cost 30 cents so cost is 0.12 cents for 2  !!!!

PS: of course, you can use the cotton bud in your ear before to cut it, so it is even cheaper !!!!!


Fully moulded, 3.5m, Fox

On sunday, I went to the col des Faisses, near corps. I met there Pierre Emery with his very nice Fox, 3.5m wingspan, fully moulded, originaly sold by Graupner, but in fact made in china by Launch Model (ex zoom model). The plane is beautiful and flies very well in addition to be georgous in the air. Hereafter are some picture I did.



Shinto maiden flight

Maiden flight of my Shinto went very very smoothly. I went to the col du glandon again because the weather forecast was indicating no wind or 5km/h maximum from west, south west. I was however expecting some thermal breeze created by the valley. when I arrived, the wind was coming from the north east valley. The time to walk to the slope, the wind stopped and switched to south valley. So, I drove 1 km, climb to the slope. The gentle breeze was about 4 to 5 m/s, not more. So I launched the Shinto unballasted and everything was perfect from the beginning: no trimming needed, CG fine, settings fine with the right amount of snapflaps, differential OK. Empty weight is 2103gr and CG is set to 86-87mm. The Shinto is very easy to fly, very precise, and manoeuverable on the ailerons. I found the flaps to work very well in thermal position and efficient in butterfly mode to slow down the plane (empty, that's right). The Shinto, as soon as it takes its speed is impressive and easy in turn, with excellent grip and EM capabilities. I need more flying time in various conditions, and some competitions to go further.


I captured my maiden flight with the GoPro. Here is the video of it. I know ... this is an ugly place for a maiden flight :) !!!


Graupner V-Venture review in Modèle Magazine

My 4 pages review of the V-Venture has been published in the July issue of Modèle Magazine.



Shinto assembly

Below are some pictures of the assembly of the Shinto. the LDS installation requires some attention as everytinh is very tight. The result is perfect, with no slop at all, removable servos despite they are bigger than recommended. In the fuselage I used the new HV 6125e from MKS, so the plane doesn't need any S-BEC, as I 'm powering it with a Li Ion 2S 2.9A battery.
Empty flying weight is 2100gr. I didn't need any lead except the one moulded and provided by Vladimir. I also produced a spreadsheet for the ballast. I found that above 1.7kg of ballast you need to put some balance lead in the nose as the CoG is moving backward of 3mm. 



Tuesday, June 24, 2014

Hacker Model Vagabond: Kit Overview

After a long long wait the Vagabond finally landed, and the wait was worth it. What is the Vagabond ? It is the first widely commercial VTPR glider, made from EPP foam and printed for a nice color design. It exists in 2 versions: uncovered, and covered with a laminate film (wings, tails and fin/rudder). It features a SB96V section, nearly 90° tail rotation and weight around 500 and 600 depending of the version.

 Below is the photo album of the kit as it arrives:
Unlike other EPP plane (foam cutted), the Vagabond assembly is well advanced. Wings are nearly finished, just needing the servos, control horn and rod installation. The fuselage need some work, like insert the carbon rods for the stifness, the sleeve for the rudder and elevator control rods, the servos tray, the root section in the middle of the fuselage.

Overall degsign is well thought, except the tail plane which is not removable. This is a shame because the wings are. Now this is perfectly understandable as the easiest way to make the tail to rotate up to 90° or nearly is to articulate it around the carbon joiner, and there the only way to secure the first half tail with the second is to glue definitively the joiner in place.

I will propose a modification that allow to remove the tail easily.
Quality of he kit is very good like this large canopy in thin black plastic that give a wide access to the radio and allow to give a nice finish to the plane.

Next time we will speak about the assembly. Stay tuned !

F3F in the Vosges (route des crêtes)

Excellent competition last week-end in the east of France (Alsace). We managed 16 rounds with 21 pilots (7 rounds on Saturday, and 9 on Sunday). Saturday, conditions were light with some crossed wind, best time at 44s. The rain came around 4pm. On sunday, we had a beautiful day, with stronger wind. Top pilots were always in sub-40. I personnaly achieved a nice 32s with my Needle 115V despite a very slow last lap after the plane stopped in the last turn . But the best time of the competition went to Frederic Hours with a superb 30.40s with his Stinger. The top 4 was very closed between Aubry Gabanon, Frédéric Hours, Mark Redsell (who came from UK) and myself. Frédéric finally won the competition, followed by Aubry (992 points), I finished third (987 points) and Mark in 4th position (986 points). A veny nice and intense competition, in a beautiful area. A big thanks to the organisers Renaud and stéphane !



And below is the usual short video from Aubry Gabanon, giving a different perspective of the slope.


[Essai en Francais] Libelle de Dream-Flight, le lancé-main pour tous !

Introduction

Suite à l'incroyable succès planétaire de la Weasel et de l'Alula, suivi coup sur coup de l'arrêt de leur production pour diverses raisons, tout le monde attendait avec impatience et fébrilité ce que pouvait nous réserver Dream Flight pour prendre la relève, quand début février son patron Michael Richter annonçait la sortie de son nouveau modèle et une première, un lancé-main moulé en elapor ! Alors que les prix des lancés-main tout composite atteignent des sommets en raison de leur construction toujours plus high-tech, le Libelle se positionne lui comme modèle de découverte de la catégorie, à moindre coût. Pari gagné ?… C'est ce que nous allons voir dans cet essai.

Un kit dans la pure tradition Dream Flight

Ce qui m'avait frappé lors de l'essai de la Weasel et l'Alula, c'est une conception particulièrement aboutie du modèle, dans ces moindres détails. On retrouve ce souci du travail bien fait avec le kit du Libelle. A l’ouverture du joli carton d'emballage vert, ce qui attire l'œil ce sont les 2 panneaux d'aile, très légers, parfaitement moulés avec un bord de fuite qui ne fait pas 5mm d'épaisseur comme sur certaines productions chinoise. Il n'y a aucune marque d'extraction sur l'extrados, les points d'extraction sont à l'intrados et sont particulièrement discrets. De plus, il n'y a  aucune marque de points d'injection, généralement un gros cercle de la taille d’une pièce de 2 euros.



L'emplacement des servos et les saignées pour le passage des fils de servos sont propres, comme les empreintes pour les pièces plastiques d'assemblage des 2 demi-ailes ou l'emplacement des guignols. Les 2 panneaux d'aile arrivent avec un jonc carbone plat installé et collé en guise de longeron, ainsi qu’une large pièce plastique au saumon prévu pour recevoir le peg de lancé (droitier ou gaucher). Les ailerons sont déjà découpés.

Le fuselage, bien que composé d'elapor, de plastique et de carbone, est terminé à 90% afin de garantir une mise en croix optimale. L'avant du fuselage est constitué d'une pièce en Elapor protégée par une coque en plastique noir brillant qui amène la solidité de l'ensemble. Le compartiment radio est moulé, que ce soit pour les servos ou la batterie de réception. La verrière en elapor a déjà les aimants collés, tout comme sur l'avant du fuselage. La poutre arrière est un tube carbone conique solidement collé avec le fuselage. Sur sa partie arrière, un pièce plastique collée reçoit le stab et permet à la commande de profondeur de déboucher sur le guignol. L'extrémité de la poutre est déjà préparée/usinée pour le collage de la dérive et la sortie de commande de direction. Au niveau de l'assise de l'aile, les inserts plastiques recevant les vis sont déjà posés.

L'empennage, en elapor a son renfort en jonc carbone plat déjà en place, idem pour la dérive. Dans le kit on trouve aussi les 2 joncs carbones pour la commande de profondeur et dérive, dont l'une des extrémités est déjà équipée d'une corde à piano pliée en Z pour la connexion au servos. Un sachet regroupe toutes les petites pièces comme les guignols, les chapes, les pièces de raccordement des demi-ailes, le peg et même un petit bout de papier de verre.

Pour terminer, le kit est accompagné d'un petit livret de 25 pages, en anglais (la traduction est en cours), très didactique, bien illustrée, pleine de conseils sur la construction comme sur le vol, en fait un modèle du genre dont bien des fabricants devraient s'inspirer. Bref, ce kit respire la qualité, et inspire confiance quant à l'assemblage à venir.

Avant de passer au montage, voici le poids de chaque élément:

Empennage et dérive: 17 gr
Fuselage 54 gr
Panneaux d'aile: 2 x 51gr soit un total de 102gr
Accessoires: 10gr
Total avant montage: 183 gr

Un assemblage sans mauvaise surprise

J’ai débuté le montage par le fuselage la dérive et le stab en guise de mise en bouche. Tous les collages ont été faits à la cyano medium qui laisse quelques secondes pour positionner les pièces à coller.

La première étape consiste à coller les guignols de dérive et de stab. Il y a une empreinte dans l'elapor pour permettre un positionnement sans erreur et un meilleur collage. Lors de l’opération, j'utilise des cotons tiges pour enlever l'excès de cyano. Puis j'ai monté le stab en place avec sa vis plastique pour m'en servir comme référence afin de coller à demeure la dérive, à 90°, en m'aidant d'une équerre.

On passe ensuite à l'installation radio. Le Libelle est conçu autour des servos Hitec HS-35HD. Ce servos n'est pas donné et 4 servos comme celui-là reviennent plus cher que le Libelle. Il existe des alternatives de taille équivalente, qui nécessiteront un petit coup de cutter par ci par là pour adapter les logements de servos. Personnellement, j'ai opté pour 4 servos Power HD DSM44, pignons métal et numérique, pour moitié moins cher que les Hitec, et plus puissant de surcroit. Les DSM44 sont un peu plus haut que les HS-35HD, donc il suffit de creuser un peu jusqu'à ce que les 2 servos se glisse afin que les pattes de fixation soient en contact avec le rebord (pas de soucis car la coque extérieure en plastique garde tout l'intégrité et la solidité du fuselage). Les servos sont maintenus en place avec un peu d’UHU-por entre les servos et entre le flanc du premier servo et l'elapor du fuselage. Les servos étant désormais en place, on peut s'attaquer aux commandes de profondeur et dérive. Les joncs carbones sont déjà à la bonne longueur. Côté servos, la fixation se fait par un bout de corde à piano tordu Z. Côté gouverne, il faut installer une petite chape plastique qui se plie et se serre autour du jonc carbone grâce à une petite vis. Attention à l'orientation de la chape, qui doit être avec la tête de la vis vers le haut pour la dérive, et vers la droite pour la profondeur. Le montage de la commande se fait en 2 temps. La chape montée mais non serrée, on connecte la commande coté servos, puis on règle le neutre et la position de la chape avant de serrer la vis de la chape pour l'immobiliser. C'est simple, léger et efficace. J'ai trouvé curieux que le jonc carbone ne soit pas plus guidé au moyen de petit bout en gaine plastique par exemple, mais une fois montée, la commande ne flambe pas, la rigidité du carbone et la petit section de la poutre en carbone aidant.

Pour terminer avec le fuselage, on revient vers l'avant pour installer le récepteur, qui devra être de petites dimensions (6 voies JR DMSS RG611B en ce qui me concerne) posé sur son flanc et  calé par de petits morceaux de chute d'EPP.  La batterie composée de 4 éléments 1/3 AA rentre pile poil vu que la partie avant du fuselage est moulée autour de ce type de batterie. Il y a même un petit compartiment en dessous pour du plomb, ainsi que sur les côtés de la batterie.

Passons à l'assemblage de l'aile.

Comme indiqué dans la notice, l'opération la plus délicate est le collage des 2 demi-panneaux d'aile. On commence par coller les 2 pièces plastiques faisant office de clé d'aile et donnant le dièdre. Le collage se fait toujours à la cyano, en évitant d'en mettre trop et que cela coule de partout. On vérifie à blanc que le deuxième panneau se positionne bien sur ces pièces plastiques et que les 2 panneaux sont bien jointifs, puis on passe au collage, en procédant rapidement mais proprement, en prenant le soin de vite essuyer d'éventuelle coulures de cyano. La cyano medium permet d'avoir quelques secondes pour positionner les éléments correctement. Une fois ce collage effectué et sec, on peut coller la pièce centrale à l'extrados.

Avant de procéder à l'installation des servos d'ailerons, j'ai collé les guignols en plastique, les mêmes que pour la dérive et la profondeur. Les servos d'ailerons étant identique à ceux utilisés dans le fuselage, donc un peu plus long, il faut donc enlever un peu d'elapor. Les servos sont ensuite collés avec un peu d’UHU-Por, palonnier en position neutre, c'est à dire perpendiculaire au servos. On pose ensuite les rallonges de servos d'environ 12cm (non fournies dans le kit). J'ai utilisé un bout de Blenderm 3M pour sécuriser les fils de servos dans leurs saignées. Les commandes reprennent le principe du jonc carbone (de diamètre plus important cette fois) avec un bout de corde à piano plié en Z coté servos et de la chape plastique emprisonnant le jonc carbone et serré au moyen d’une petite vis. Reste à poser le peg, un tube carbone, qu'il faut poncer sur les 2/3 avant de le rentrer en force (pas de collage) dans la pièce plastique située au saumon.

Je me suis permis de rajouter quelques bandes de couleurs peintes à la peinture acrylique en bombe spéciale polystyrène histoire d’améliorer la visibilité du planeur en l’air.  J'ai obtenu la position arrière du centrage indiqué avec 20g de plomb (5gr sous la batterie, 3x5gr sur les côtés). Comme ceci,  la balance indique 275gr, soit un poids légèrement inférieur à celui indiqué par le constructeur, c'est suffisamment rare pour être signalé. Globalement, je retiens que le montage du Libelle ne réserve aucune mauvaise surprise. L'aboutissement de la conception et la qualité des matériaux et accessoires y contribuent largement.

En l’air !

Quelle belle coïncidence que cette météo de début mars, son anticyclone et l'absence de vent pour l'essai du Libelle. Le premier vol a eu lieu sur la pente du club, sans aucun vent, puis plus tard dans l'après-midi avec une minuscule brise  thermique,  anémique. D’autres séances de vol en plaine ont eu lieu les jours suivants, et j'ai eu l'occasion de le faire essayer à plusieurs collègues afin de confronter nos impressions. Regardons dès lors les différents domaines de vol :

Le lancé

Le lancé standard par le fuselage ne présente aucun intérêt car ne permet pas d'insuffler de l'énergie au  Libelle, on le réservera à la pente. Le lancé avec la technique « discus » est facile même pour le débutant comme moi. J'ai installé un altimètre sur mon récepteur afin de mesurer précisément l'altitude atteinte. L'altimètre donne 25 à 27m pour mes meilleurs lancés. Un lanceur expérimenté pourra sans problème dépasser les 30 ou 35 m selon moi. Cependant la structure du libelle montre ici ces limites: L'aile se déforme facilement et dissipe une grande partir de l'énergie, ce qui n'a rien de surprenant vu la destination du Libelle. Alors oui les pilotes les plus expérimentés ou les plus exigeants risquent d'être déçus, mais le libelle n'est pas conçu pour rivaliser avec des machines 4 à 5 fois plus chères, qu'on se le dise. Et croyez-moi, avec 25m d'altitude, on peut faire déjà plein de chose, explorer le terrain, accrocher les thermiques, etc. … et c'est bien là l'essentiel.


La chasse au thermique 

Le Libelle nous montre là tout son potentiel. Tout d'abord, le Libelle est très agile et léger aux manches. Il fait preuve d'une vitesse de croisière rapide permettant de couvrir du terrain. A l'opposé, il est capable d'enrouler littéralement sur place, tournant presque autour du saumon. L'efficacité de la dérive est indéniable, et je me suis surpris plusieurs fois à engager le virage uniquement à la dérive. Autre point fort du libelle, c'est le changement radical de comportement en fonction de la courbure du profil. En lisse, le planeur est fin, très fin même. En position négatif (ailerons 1mm vers le haut), le Libelle traine encore moins, facilitant les prises de badin et la voltige malgré son faible poids.

En position thermique, avec 2 ou 3mm vers le bas, le Libelle s'assagit, signale de manière plus claire les zones de portance et de déportance. En spirale, grâce à cette portance supplémentaire, on peut extraire un maximum de hauteur, en volant aux grands angles sans aucun risque.

En jonglant avec les 3 positions de courbures, on peut bâtir une vraie stratégie de vol, en alternant transition, spirale, de manière assez dynamique, donc très plaisante. A l'opposé, en fonction des conditions (restitution du soir, air particulièrement neutre), le libelle aime aussi voler à vitesse réduite, en optimisant le taux de chute en jouant sur les volets. Le décrochage ne s'obtient qu'en insistant lourdement et se traduit par une petite abattée facilement contrôlable.

Voltige

Même si le Libelle n'est pas spécialement prévu pour cela, il est toujours intéressant de pouvoir en faire pour consommer l'altitude si chèrement gagnée ! Sans surprise les figures verticales comme les renversements ou les loopings manquent d'amplitude. On peut compenser un peu en utilisant la courbure reflex (ailerons vers le haut). Le tonneau et le tonneau à facettes passent sans problème. Le vol dos avec de la courbure reflex est une simple formalité.


Atterrissage 

 … de préférence dans la main ou dans les hautes herbes à cause de la sous dérive qui dépasse beaucoup, mais c'est normal, tous les lancés mains sont conçus comme cela. Je vous recommande de rattraper le libelle de préférence par le fuselage et de ne pas aller taper le bord d'attaque, car la mousse à ses limites mécaniques et aura tendance à se marquer. La position aérofrein vers le bas des ailerons ralenti bien le planeur

Conclusion:

Le Libelle fait selon moi un sans-faute et atteint parfaitement son objectif. Pour un prix abordable et avec une qualité de kit irréprochable, il fera les yeux doux aux pilotes désireux de s'essayer au lancé main sans pour autant investir. Et même si la hauteur des lancés est en retrait par rapport aux lancés main composite, les performances en vols sont excellentes et étonnantes à en oublier la matière dont il est fait. On se prend au jeu d'accrocher un thermique de passage au bout de quelques lancés, d'explorer le l'espace de vol, raccrocher à 2 m sol, revenir en transition d'assez loin pour poser dans la main. Bref, ce libelle est exaltant et se positionne d'entrée de jeu comme un bestseller et il y a fort à parier que certains d'entre vous, après y avoir gouté, se lanceront plus sérieusement dans la pratique du lancé-main ! Bon vols à tous !

Caractéristiques

  • Envergure 1.20 m
  • Surface 21.3 dm2
  • Poids en ordre de vol 275 g
  • Charge alaire ~ 13.0 g/dm
  • Allongement 6.8
  • Profil Propriétaire N.C.
  • Cordes 21,5 / 19,5 / 12,5 cm
  • Commandes 4 servos: ailerons, profondeur, dérive
  • Fabricant Dream Flight (USA)
  • Distributeur France Flash-RC
  • Prix Public 124,90 Euros

Réglages

CG: 8 cm

 (Note: «-» signifie vers le haut, «+» signifie vers le bas)

Profondeur : + ou - 14 mm
Dérive : + ou – 25mm
Ailerons : - 20 mm  + 15 mm
Courbure : 
Reflex (Lancé ou voltige): - 1mm
Thermique : + 3 mm
Atterrissage : + 15mm


quelques videos du Libelle: