Ballasting a F3X sailplane

It is always a problem to know exactly how to ballast a F3X plane given that they are several ballast compartiments with different size/volume, and none of them is exactly at the center of Gravity. I created the following spreasheet to help you how to determine the ballast, and also calculate the CoG variation.

How to use this spreadsheet ?

Enter in the yellow cells:

• The position of the CoG
• The position of the different ballast compartiment (measured at the center of the compartiment)
• The weight of the ballast slugs for each compartiment
• The empty weight of the plane

As ouput, it will give you:

• The total ballast weight
• The flying weight
• The wing loading
• It will highlight in red when exceeding the FAI wing loading of 75gr/dm2
• More importantly, it gives the variation of the CoG.

Feel free to report mistakes, bugs if you find some. Thank you.

- Download the spreadsheet -

Schwing 88 kit overview

The Schwing 88 is the first allround slope model born from the partnership between James Hammond (the father of the Strega, Typhoon, Vector, Minivec, and some others ...) and Tony Fu from SlopeRacer.co.uk.

The Schwing 88 is a very nice looking 2.23m wingspan slope plane which includes improvement from previous JH designs, based on feedbacks and learning experience. It features new combination of airfoils, semi eliptical lift distribution, large control surfaces. The fuselage is slim and with a canopy, but still host a massive ballast tube and the servo tray for 2 servos, the receiver and the battery.

The plane is distributed worldwide by SlopeRacer.co.uk or by its distributors in some countries (i.e SoaringUSA). I received one exemplar of the first production batch.

So, what do you get ?

The wings are fiberglass. The finish is clean and the level of completion is high, as expoxy wipers are done, brass control horns are installed, and a carbon reenforcement is in place in the servo bay. On the root, the hole for the wing connector (green MPX connector size) is done, and the aluminium centering pins are installed. Servo bay can host any wing servos (10 mm), and possibly some micro 12mm servos.

The wing joiner is massive, especially for the plane size. It will certainly survive to all abuses you will do to the plane !

The Fuselage is a nice piece of moulding. It comes with  bell crank installed, control snakes in place. The rudder is finished with a brass control horn in place.A large carbon reinforcement goes from the fin to the canopy, the front of the fuselage is in fiberglass to be 2.4 friendly. The Canopy is in fiberglass, painted in black. The 2 pieces tailplanes with control surfaces are also finished.

In the accessories pocket, you find the servos covers (flat), the tail joiners, a superb carbon prepeg ballast tube, to host 19mm ballast slugs, an awasome servo tray, laser cutted, perfectly ajusted to the fuselage (no adaptation required), designed to receive 2 tiny 12mm servos, the receiver, and the battery. I would say that a 4 cells 2/3 C (1500 or 1600 mAh) seems the best choice given the space.

Connecting all the parts together allow to see that everything fit perfectly together. No misaligment, no hard point, no slop. This is excellent.

My only "negative" point, but I was aware of, is that the balance point of the fuselage empty and alone is far rear, at the middle of the boom when usually it is around the trailing edge. This means it will need lots of lead to balance it well. This is not surprising because of the fin, and I remember I had the same problem on the Typhoon, which didn't prevent the plane to fly superbly.  According to SlopeRacer, the Schwing would require around 170 to 190g of lead. Overall, I'm very pleased with the kit quality, the level of completeion and the quality of the accessories. Let's have a quick look to the parts weight. This gives the following:

• Left Wing: 431g
• Right Wing: 423g
• Left Tail: 25g
• Right Tail: 26g
• Tail joiners: 6g
• Fuselage: 239g
• Wing Joiner: 115g
• Ballast Tube + servo tray: 27g
• Total: 1292 g

The RC equipement I choose: In the wing, I will use 4 DS 6125-H that I had in stock. For the rudder and the elevator, I will go for 2 x DS6100. They are tiny but strong and powerful servos. I used them already in my Willow and my Needle 100 and I'm very statisfied with them.

Assembly will start in the coming days, and you will be able to follow the progress here. Stay tuned !

Practice session at Le Col du Glandon

This place is where french F3F was born in 1994. With the coming yearly french league context next week, I drove there to meet with 2 F3F mates and enjoy the north slope. This is the first time this year that I go there, but I should really go more often as the north slope is really appropriated for F3F with its sharp edge. But the main characteristic of this slope is the fact that the breeze is very laminar and consistent, with no or very few thermal influence. Even if the time achieved are not impressive, the flying experience is absolutely excellent, and you can do 200 laps with the same regularity, you can work on the trajectory, the turns, the ballasts, etc ... Wind was blowing around 6 to 7m/s. I started the afternoon empty to finish with 390g of ballast. 
It has been also the opportunity to try my brand new and shiny Canon EOS 650D, a important but necessary investment to continue to propose you premium photography on Planet-Soaring.
Here are the very first shots taken yesterday afternoon.

Font d'Urle video clip

I just finished the video clip about Font D'urle F3F contest. Hope you will like it. I has been film with the GoPro on a 3m boom and my Lumix FZ100. No animals were harmed during the filming, but some sailplanes did (at the landing) ! Enjoy !

JR Propo XG8 / XG11 field charging solution

The XG8 and XG 11, powered by a 2S 1400 mAh LiFe battery, have the particularity to integrate the battery charger into the transmitter case. They need a 220VAC / 9VDC adapter, provided with the radio. This solution works great at home but the downside is when you want to recharge your transmitter on the field/slope, and that you don't have 220V source available.

I found a smart solution to recharge my transmitters on the field. I bought a CCBEC from castle creation, which is programmable using the USB link to purchase separately, and which is the only UBEC to be able to go up to 9V, at the opposite of all other BEC which deliver 5 or 6V, not more.

I prepared some cable to use with the CC-BEC, on one side to connect to the transmitter plug, on the other side to connect to a 3S Lipo battery, or to connect to a 12V power source. I will also prepare soon a cigar lighter plug.

This charging solution is very convenient, in addition to be an excellent backup solution. It's light, can stay in the transmitter bag, so you have it always with you.

Greatly recommended !

Video: slope soaring patrol flight

The second video from Jean-Marc Zuliani has been filmed on the slope of L'Alpe D'huez. this is an action video with onboard camera and unfortunately a mid air at the end. Story doesn't tell about the damages :( !

Video: A sailplane trek to the "Plateau d'Emparis"

Jean-Marc Zuliani released 2 new videos recently. This first one has been filmed on the "plateau d'Emparis", a wild and protected place in the heart of the Alps, between L'Alpe D'huez and the "Ecrins' National Park", offering one of the most beautiful landscape of the area. Nice video and editing !

Font D'urle 2012

This competition is a special event in the french F3F calendar because the organisers have an authorization to fly there and because this is forbidden the rest of the year, being in a very restricted/protected zone. This difficult access make it a sort of pilgrimage for all the french F3F pilots, but also for our friend from Switzerland like Reto and Christian. This year has been an excellent year, in term of participation with almost 30 pilots, but also because of the weather and 2 days of south wind.

On saturday, the wind was not very strong but in round one, but Sebastien Lanes did a 34s that remained the fatest time of the day. We ended with 5 rounds in the pocket, and also with some planes damaged during landing as some pilots experimented time to time rotors during the approach. At the end of the day, Alain Galinet from Briancon was leading, followed by Sebastien Lanes and Matthieu Mervelet in 3rd.

On sunday, we started earlier as the wind was already blowing. Conditions grew up all the day to become huges in the afternoon. We managed 7 rounds, and last rounds were mainly sub-40s !!! Arnaud Kreps did a 31s, his personnal best, but also the new record of the slope. but on the ranking side, it was clearly Matthieu's day as Matth  did only sub 40s, including several 33s. He won the competition by a good margin.

In addition to be a unique and superb place, this second day allowed us to touch the potential of the slope to produce very fast time, and we can even imagine one day to break the work record on this slope.

We all hope that next year the National championship will be organised there, but this depends of lots of administration authorisations so we will cross fingers for it to happen !

I did lots of video sequences during the week-end. Give me some time for the editing and I will try to not disappoint you.

Stay tuned !

Alliaj HM Slim

Aeromod release a new fuselage for the famous Alliaj HM. The new fuselage follow the current F3X trend, so is slim, with the servo tray inverted, with a big ballast tube in the fuselage. This week-end, Jean Luc Foucher used the new Alliaj HM during the competition of Font D'urle. A good opporunity to have a look to it and take some pictures and video. The new Slim fuselage, event it is difficult to say that it improves perfomances, clearly gives a totally new look and elegance in flight as ou can judge on the video below.

Hints and Tips: using a heater cable for fuselage repair

During the FAI contest of Briançon, I learned a great way to repair quickly and solidely a fuselage boom. The idea consists in using a ground heater cable that guarantees a regular and even heating.

This heating cable is usually used in aquariums, as well as in terrariums. I bought mine in a Botanic shop. 3 models exists: 25, 50 and 100W. For our purpose, the 25W is the one to choose, as it is already 4.30 m long.

One you have done the repair with carbon/glass cloth or tape, you first surround with some large tape or thin plastic sheet, then you roll up the heater cable around the boom and plug it to the 220v. According to the people using it, it provides a temperature around 30 to 40°.

You can also use a sheet of aluminium around the boom before to roll up the heater cable. This will help to propagate the heat all around.

After the night, the fuselage is ready for sanding and painting (if you have time) or flying if you are on a hurry :)

Technical data: Hydor Hydrokable Ground Heater 25 W:

• Heating Power: 25 W
• Cable length: 4.30 m
• for aquaria: 40 up to 65 litres
• 230 V/50 Hz, with Euro plug
• Price: around 30 Euros

Col de Menée

This afternoon, I went to a super F3F spot that has been discovered 2 years ago and that we used during one day of contest of the french league. The only problem of this slope is that it is difficult to reach: 40 minutes of walk, and about 300 meters of altitude to climb, so you need to not take too much planes or equipement to stay light. I took only one Pike, my compact camera, the Go Pro, but also the 2 kg of ballast ...
The slope is very deep, and "capture" the wind very well. Because it is facing north, it is not too much influenced by thermals. Time to time you fly a bit faster, but the difference is not huge.

I was alone on the slope all the afternoon, so flew 2 hours non stop with 700g of ballast. The lift has been consistent during all the time, really a super spot !

Here is a short video I did.

T9 Hobby Sport Magnetic switch

Magnetic switches become very popular in the F3X world because they are very convenient to use in slim fuselages and because they are finally safe as they are passing if faulty during operation.
After testing 3 other magnetic switches, I received this new one from T9 Hobby Sport for review. It is now installed in my Willow F3F and worked flawlessly until its installation.

This T9 hobby sport Hall effect magnetic switch is a nice piece of hardware, with double side board and lots of surface mounted components. It differs from the competiton by proposing 2 things:

1/ A battery charge lead: This is very convenient because now you dont need to unplug the switch when charging. You can really locate the switch in a unreachable place. The charge lead is directly connected to the battery wire so in theory, there is no limitation in term of current or delta peak détection.

2/ A temporisation when switching off: To switch on, just present the magnet over the circuit and the effect is immediate. To switch off, you need to let the magnet 3 seconds over the circuit to really switch off. I measured several operations and mine is more around 4 seconds. This protection prevents to power off inadvertently. But the downside is that you need to mark precisely the location of the switch if you don't want to become crazy, searching where it can be can.

A blue LED indicate brightly when the switch is in use.

Mine came with Futaba connectors so I needed to cut the keyway. The wire has a section of 0.5 mm2 which means that you can pass 5 to 7A without problem. This is more than enough for our use. IT can be used with 1 Lipo Cell, 4 or 5 NiMh, or 2s Lipo or Life batteries. As usual, the standby current is negligeable compare to our battery capacity, so you can let the switch connected (but off) for months.

Specifications:

• Supply Voltage 3V -8.7V
• Dropout voltage (Input vs output) 100mV @10.2A
• Continuous Operating current - ~ 20A
• Peak Output current - ~ 50A
• Standby Current (Off State) - ~ 50μA
• Operating temperature range -40°C 80°C
• Dimensions: 27 x 11.5 x 6mm
• Total cable length Approximatively 28 cm
• Weight Including all cables ~ 9g 
• Distributor: T9 Hobby Sport (UK)

I will prepare a short video in the coming days.

New pictures of the French Alpine Cup (Briançon)

Joël Marin, one of the 2 CDs at Briançon for the French Alpine Cup took some pictures during the contest. Here is the photo album. The idea of Joël was to have at least a picture of each competitor. Hope he doesn't forget somebody :)