Saturday, August 31, 2013

Video: ASW15 aerobatics

Here is a video I did 2 weeks ago and showing my friend Gérard Prat doing low speed aerobatics with a 4m wingspan ASW15 from Airtech. You will notice the intensive use of the camber to slow down the plane and create lift as conditions were light.

Tuesday, August 27, 2013

Needle 115, the video

Below is the video I filmed on sunday while doing the maiden flight. The wind is starting from around 6m/s and increasing to 9m/s, so the plane is empty at the beginning, then with 200g, then 640g of ballast. Nothing replaces a real confrontation in competition, but this video allows to glimpse that the N115 is well born and has a real potential for F3F. I will do new videos as soon as I can fly the Needle again.

Needle 115 from Pierre Rondel on Vimeo.

Monday, August 26, 2013

IAR 35, a Romanian acrobat glider

Thuro, the designer and father of the popular Needle serie is working in parallel on a very interresting project of a big aerobatic semiscale.

The choice is a nice looking Romanian Aerobatic Glider, called IAR 35, an all-metal full acrobat glider. Only 4 exemplars remains in the worl, all in Romania. After the accident of one of the prototype, the IAR 35 has been grounded, and the production has even not started.

The semi-scale is 1:2,18 scaled which will give a 5.3 wingspan.

No or very few information are available for this plane, so Thuro didn't find any sketches or 3 views plan. He simply started from good quallity pictures and a Romanian contact of Thuro did some measures on request. Then Thuro developped the whole model in CAD, and also created new airfoils for it.

The project is at the beginning. The master of the fuselage is done, and the mould too. The next challenge is now to mould a llight but strong fuselage which is not that easy with such size.

Below is an interresting video Thuro sent me about a new technic using vacuum infusion of the epoxy resin, in order to put the minimum of resin in the fabric:

Pike Electro Maiden Flight

I finally had a chance to try the Pike Electro last week-end but, again, had some trouble with the motor (Kontronik Kira 480-43) and ESC (Castle Creation ICE Lite 100). Hopefully maiden flight was at the slope, so I could fly without motor for the launch before to start the motor. Problem is that each time I was starting the motor, the ESC was cutting it after 2 sec (over current detected, according to the logs ! ). This is very surprising because following advises from  specialist, I sized down the propeller to 13x8 in order to stay in the confort area, and the current was not supposed to exceed 70Amp maximum. The cut threshold was set at 100A. Several attempts has been done, and each time the ESC was cutting after 2s, except during the last start where I got more motor time (about 10s), but this time when I stopped, I didn't have any break despite it is correctly configured and it was working well earlier !!

To be honest I'm lost with this setup. This ESC is a brand new one, and has been replaced by Castle under warranty because the first one melted the shrink tube and shown 200A current peak !!!

Has the Kontronik motor been damaged (having micro shortcuts) after the very first attemps with the Rotmilan and the first ESC ? is the new ESC malfunctioning again ? No Idea...

In the meantime a friend of mine crashed his Electro Dingo with  CC 75A ICE Lite ESC from the same brand, while he was circling (motor off !!!!). He lost the radio control of the Dingo (as he was using the BEC) which dived from 200m with the plane totally destroyed as a result. The ESC "just" burned, despite the plane is 2 years old without any damages, or hard landing with the same setup. ununderstadable. Yesterday, another modeller burned his 100A ICE lite ESC while starting the motor.

In my case, I know that I did a mistake by choosing this high Kv motor requiring high current in 3S, but it should work according to the spec and simulation, even with some margin.

As a consequence, I don't trust the ESC and have no idea about the shape of the motor, so I finally decided to order a new motor first, then a new controller. the new motor is an interresting combination with a Leopard motor and a Reinauser gear. This combination is proposed by SlopeRacer in UK and gives plenty of satisfaction to the happy owners that I discussed with by email and on the forum. Depending of the propeller choice and battery, it can deliver up to 1.4 kW of power !!

In my case, I opted for a 3s battery, and a 17x11 or 18.5x10 propeller, resulting in a about 750W, which is good enough for my use. For the ESC, I chose the YGE90LV, a "made in germany" controller. YGE has an high reputation in the helicopter and & airplane world. The Controller is on its way to my home at the time I'm writing these lines.

The good news is that the layout I chose with the MKS DS 6100 in the tail is prefect, and that the Electro Pike is fling exactly as the "normal" Pike, which is no surprising as I just copied the settings to another memory on my XG11 and added the Motor command.

I will of course keep you all posted of my progress !

Needle 115 maiden flight

Yesterday, I took the opportunity of a few hours weather window to maiden the N115.

It weights 2371g, but I needed about 300g to obtain the right CG at 89mm. With the new fuselage coming, I hope I can go down to 2200g which should be ideal from my point of view.

The first flight was in light condition, let's say around 6m/s. The Needle has been launched and every thing went perfect, no trim needed! In the air, the N115 was very smooth, tracks exceptionnaly well, less noisy than average, and already showing a good speed in straight line, and excellent energy management turns capabilities. No bad habits detected.

Later in the afternoon, the wind increased a bit, so I put first 200g in the joiner, then later 1 slug in the wing compartiment (240g) and 1 more slug in the joiner (total 640g), as the CG is approximatively located on the rear half of the joiner.

I did some runs starting with altitude and has been impressed by the acceleration, the speed and the energy in turn (EM turn). the Needle is happy whatever the turn style like bank and yank or larger turns like energy management.

My settings need definitively some adjustements, and I need more flying time, but first feelling is extremmely positive, and I see an excellent potentiel in the N115 for F3F.

I did plenty of pictures you can find below:

I also filmed with my GoPro and my EOS 650D so I would be able to edit a first video about the N115 in the coming days, so stay tuned !

Anyway, I'm excited to fly it again !

Needle 115 assembly

Nothing special to say about the assembly of my Needle. In the fuselage the work consist in installing the servos tray. I made a longer one in order to go almost up to the wing root as reinforcement. The tray is glued first with epoxy, with some carbone in the corners. Then I applied 2 layers of 110g.m2 fiberglass going on the side of the fuselage to make the traya nd the fuselage as one piece. I do this on all my F3F ships and I'm very satisfied with the robustness it gives. The Elevator servo is a MKS DS 6125-H a,d the rudder one is a MKS DS 6125-e. I used a tiny RG611B  receiver, DMSS modulation, 6 channels. The battery is an hyperion LiFe 2100 mAh which fits very well in the nose. The Zepsus magnetic switch is connected between the battery and the receiver. This means I'm in HV, no voltage regulator in front of the receiver. For this reason, I installed 2 S-BEC in front of the rudder and elevator servos.

I didn't follow the standard servos installation in the wing, using epoxy horns and fixed metal rod, bended at the exact size, like on my Needle 100. For the N115, I wanted to reused the system I have on my 2 Pikes Precision and that give me entire satisfaction as after 2 seasons of intensive use, I have still no slop at all on the servos !
The system consists in using the RDH and Fu-Fix external ball bearing, mounted on MKS DS 6125 Mini on the ailerons (with a 1.5A S-BEC in front) and MKS DS 6125 glider on the flaps (with a 2A S-BEC in front) . This requires more attention during the installation, but the result is absolutely slop free. On the ailerons/flaps side, I now used MPjet brass horns as I have been disapointed by the MPX metal horns which can bend, then break during hard landings. The M2 MPX clevis is perfect to use with the MPjet brass horn. Of course at the end you see the clevise exiting on the upper skin, but I prefer a good servo and slop free installation than a invisible one that gives flutter, and some maintenance at the end.

With the preproduction fuselage, I needed lots of lead in the nose to obtain the recommended CoG at 89 mm. The N115 weights 2371gr. With the production fuselage, I think it is possible to end around 2200gr which is ideal for F3F.

For the maiden flight, I programmed the settings quickly, knowing that I will need ajustement. Let's go the slope !!!

Friday, August 23, 2013


During the summer, Corps is often visited by people spending their holidays in the area to enjoy mountains, but also flying conditions. The week-end of the 17th of August, I wend again woth Joël Marin to the slope of Corps and met there Gérard Prat from Bellegarde, Michel Leroyer from Britanny, Eric Merlin from Nice and Christian Magnus from Germany. Conditions were small at the beginning but growed a bit during the afternoon, so we could have lots of flying time. It was the opportunity for me to try the Alpina 5001 from Tangent, thanks to Eric who kindly propose me the transmiter, which I couldn't refused ! I flew the Alpina 2 times 15 minutes, did some thermalling, some flyby and some aerobatics. The plane has lots of presence in the air, has a high cruise speed, and the wings are very stiff. Overall a very nice plane that will probably become a collector if Tangent is not waking up quickly, because after retrieving their freedom after the acquisition of Graupner by SJ propo, Tangent didn't move at all. This is a shame because they have a very nice product range.

Friday, August 16, 2013

Livre: RC Aero Design, l'aérodynamique à la portée de tous

(Note: English version to come soon)

Quelques mot sur l'auteur tout d'abord. Ingénieur de formation mais surtout aéromodéliste de longue date et pigiste pour les magazines spécialisés, Franck est un concepteur insatiable qui a commis déjà beaucoup de modèles (donc beaucoup ont été publié d'ailleurs dans les revues) qui ont marqué les esprits, je pense notamment au Crobe qui est un best seller. Il est aussi l'auteur du Logiciel PredimRC, décliné en 2 versions (l'une freeware et l'autre plus évoluée et intégrée, payante).  Après avoir écrit un certain nombre d'articles/dossiers technique sur la conception de modèle et sur l'aérodynamique qui est son pêché mignon, Franck a décidé de passer à l'étape supérieure en nous proposant cet ouvrage RC Aero Design.

152 pages pour tout savoir !

Le livre se présente au format A5 avec une couverture souple. La qualité de l'impression est d'excellent qualité, ainsi que les nombreux schémas explicatifs qui accompagnent le texte. Les quelques photos par contre ressortent un peu moins bien, le papier n’étant pas un papier glacé. Globalement, c'est du tout bon, qui n'a rien a envier aux produits de grands éditeurs largement diffusés. Un grand bravo donc à Laurent Michelet pour cette première publication très réussie !

Après avoir rapidement passé en revu le contenant, passons au plus intéressant, le contenu: RC Aero Design se veut un livre de vulgarisation qui permet au plus grand nombre de comprendre la mécanique du vol, en proposant 2 parties, la première pour poser les bases, la seconde pour expliquer pas à pas les étapes et la méthodologie de la conception d'un modèle.

La première partie, longue d'une grosse  vingtaine de page, s'attaque aux concepts de base mais néanmoins essentiels qui permettent de mieux appréhender les bases de l'aérodynamique comme le vocabulaire, comment se créé la portance, le nombre de reynolds, le CG, la notion de foyer, de traînée, traînée induite. Pour certains ce sera nouveau pour d'autre, une bonne piqûre de rappel ou même une remise à niveau.

La seconde partie, beaucoup plus importante, rentre davantage dans les détails en proposant un cheminement bien structuré qui démarre à la définition des besoins, le dessin de l'aile le choix du profil, avec une bonne explication sur comment lire une polaire, la conception du fuselage, du stab, les interactions entres les différents éléments, le calage. Puis est abordé ensuite la conception des gouvernes avec quelques détails sur la mécanique et cinématique.
Une grosse partie est ensuite consacrée à l'analyse des performances en vol, du plus basique avec le test du piqué au plus technique avec l'utilisation des volets, snapflaps, l'influence de la charge alaire. Quelques paragraphes sont dédiés également à la motorisation, bien que l'on sente que cet ouvrage est d'abord écrit par un planeuriste pour les planeuristes, et cela je ne vais pas m'en plaindre !!!

En tout cas on sens de la part de l'auteur le soucis d'expliquer simplement et clairement les choses. C'est ce qui permet d'ailleurs d'avoir plusieurs niveaux de lectures, du débutants dégrossi au pilote chevronné, car chacun y trouve son compte. Il n'est pas besoin de lire le bouquin d'une seule traite, on peut picorer dedans, en fonction des questions que l'on se pose, des problèmes que l'on rencontre. Je pense d'ailleurs que c'est comme cela que l'on retient mieux les choses.

Bref, cet ouvrage et le genre de livre que l'on achète et que l'on garde longtemps, servant de référence, de filet auquel on se raccroche. Ensuite rien n’empêche de creuser un point particulier en allant pêcher des infos ailleurs. RC Aero Design a le mérite de regrouper beaucoup de chose, et de manière facile à appréhender, dans un format compact.
Alors si vous n'avez pas encore ce livre, vous savez ce qu'il vous reste à faire ! La commande se fait le plus simplement du monde en ligne sur le site web du magazine RCpilot.

Editeur : KoolPress. 152 pages, Format A5, couverture souple, Prix 25 €

Wednesday, August 14, 2013

Some pictures

Here are some pictures taken last saturday in Corps, with some nice gliders, with pretty good flying conditions.

La Meije - La Grave

La Meije (3984m high) is a mountain in the Massif des Écrins range, located at the border of the Hautes-Alpes and Isère départements. It overlooks the nearby village of La Grave, a mountaineering centre and ski resort, well known for its off-piste and extreme skiing possibilities.
While driving several times from Grenoble to Briançon, I always promised to myself to stop there one day, and do some aerial video of the place. I did it last sunday by a beautiful summer afternoon. It was very windy (probably more a strong thermal breeze created by the valley), so I found a place with a slope facing the wind. I flew the Solius equiped with the keycam 808 # 16 V2 Lens D. Lots of turbulences, I had many difficulties to land safely, but I least I flew there and obtained this video.

La Meije La Grave from Pierre Rondel on Vimeo.

Wednesday, August 7, 2013

Flying session at col des Faïsses

Below are some pictures of last sunday afternoon at col de faïsses near Corps. Flying conditions were disapointing with a very light south wind. On top, I discovered that I forgot my Pike Precision fuselage at home, some had only my Needle DSL which was not really adapted for such light conditions. Anyway, I could fly a bit. Thomas Delarbe did a flight with his brand new Stinger, and Frederic from the 2013 national team  did some laps with his freestyler 3. It is a shame because the day before (Saturday) and the day after (Monday), conditions were great with strong wind. This is slope flying, everyday is different, even on the same slope.

Transport/Protection bags from is based in Austria and manufactures premium quality wing/fuselage/tailplane bags for modelers including airplanes/gliders and helicopters. I received the N115 set of bags and I can tell that I'm impressed by the quality, finish, design.

Bags are made of high-quality 3-layers padded fabric (200 g/m² and 300g/m² are available), silver color with a light reflective effect that protect from the sun. An orange reinforcement fabric binding stip is used all around the bag to make a nice finish, a perfect combination with the grey from my point of view. Binding strips are available in the colors black, red, yellow, blue and orange.

Bags are closed with large velcro strips, and the fuselage bag is finished with a premium quality zip. Tail bags and fin bag (for the N115 which is a crosstail glider with a removable upper fin) can be used with the tailplane mounted on the fuselage.

All bags are really beautifully made, and components fit perfectly in them.

To know what glider bags are available and if your beloved glider is in the list, I let you see on website (which is unfortunately only in german).

Monday, August 5, 2013

Needle 115: New Kid On The Block !

I'm a very lucky man as I received the very first Needle 115 (except the prototype of Thuro). This is a preproduction model in the sense that the fuselage is the original one with removable upper fin, a one piece tailplane, and a fuselage moulded in 2 piece. This will be changed soon to a more standard fuselage as the current fuselage is harder to produce. The Needle arrived in a very well packed parcel, everything was solidely secured, so normally no damages could happen.

The Needle 115 is the intermediate model between both famous Needle 100, which is a super fast model in medium to strong condition, but handicaped by it smaller size, and the Needle 124 who desmonstrated to be very competitive in F3F, but sometimes too large with its 3.15 wingspan. The Needle is the new kid on the block, who will fill in the gap between the 2 other Needles.

How does it look ? Esthetically speaking the new Needle 115 is mixing the wing shape on the Needle 124 with the Needle 100 like fuselage, but with a larger fin and tail, which makes him better proportionned visualy. The fuselage is 2.4Ghz Friendly, with plenty of kevlar in the front part of the fuselage. The rear boom of the fuselage is very rigid and strong.

Moulding quality is absolutely superb, shiny finish, prefect details, the wings come together on the fuselage with no hard point with the joiner, and fit perfectly on the root of the fuselage.

No fuselage ballast, everything is in the wings or in the joiner. I took the brass ballast set option which weight 2.288g (Wing Ballast: 1445g, Joiner Ballast: 843g). With this set all the wing compartiment are not occupied. The front compartiment can accept shorter slugs. I will look at the ballast distribution soon, by using my spreadsheet that I will modify for the N 115.

Weight of each Component  is as follow:
  •     Right Wing: 575g
  •     Left wing 579g
  •     Fuselage: 311g
  •     Upper fin: 31g
  •     Tailplane 63g
  •     Joiner 84g
Total empty weight: 1643g

I let you look at the pictures of the kit I took yesterday. It is now the time to start the assembly. Stay tuned !

 The F3F contest of Briançon is always a week-end apart in the season because of all the specificities like the 4x4 ride to the slope, the high altitude slopes (2200 and 2400m), but also the warm and friendly hosting by Frederic Hours with a BBQ the first evening, and a Pizza party the second evening. This year, we have flown the entire contest on the south slope, a large and deep slope without real edge. On Saturday, we managed to start on time and did 7 rounds with 30 pilots before to end the day. We had some fast times below 40s, but also some slow times with some cross wind from the left. At the end of the day Frederic was strongly installed at the first place of the ranking, followed by me, Andreas Fricke and Sebastien Lanes. 

Sunday, the wind was supposed to be stronger, which was the case but finally it was not better because was a bit crossed and was increasing the te difference between pilots having a thermal, and pilots flying without. We did additional 4 rounds for a total of 11 rounds, but we had lots of refly because of the wind direction. I paid cash in the round 10 with a 50s against a 36s. Frederic remained very solid, Sébastien too, and Andreas, with his new Pike Precision was really consistent and good, finishing at the second place. Finally at the end of the compétition, the 2013 national team trusted the podium, which is a good news with the coming european championship. We all left Briançon very happy and statisfied to have spent a really good week-end in a splendid place. A big "Thanks" to our hosts Frédéric and Edwige ! Thanks you also to Alain, the co-organiser, and all the other people (pilots included) who contributed.

Below is a short video clip I did during the week-end.

Briançon 2013 from Pierre Rondel on Vimeo.