Friday, January 19, 2018

Quantum update !

The Quantum n°001 is out of the moulds !!!!! Remain the cut ot the flaps/ailerons. It should land at its new home end of next week :) . Stay tuned !

Sunday, January 14, 2018

Home made tail protection covers

F3X competition planes are sometimes damaged during transportation, especially because we let the V-tail in place.

Tail covers provided with the glider, or bought as an option, a nicely made, but appears to not fully protect from shocks and prints.

I'm now using home made covers using a 2.5 thick foam called "Isolene". This foam has on one face a thin aluminuim sheet.  It costs around 5€ per square meter, given thatt he roll is 1.5m large.

Icut at the shape of the tail with a 1.5cm margin all around the tail.

Then I glue using hot glue, but proceeding 20 to 30 cm at a time, let dry, and continue. Then, with scissors, I cut the excess (around 5mm).

The covers are staying perfectly in place and are never sliding. They also keep the control surface aligned.
The density of the foam is protecting well the surface, and the 1cm excess all around is a good shield against unwanted shocks while manipulating.

I recently found in the same shop a even more dense foam, all white this time, called Isol'choc. Price is a bit more expensive (7€ per square meter). I haven't try yet to glue them, but I think it should worl the same.

Wednesday, January 10, 2018

Quantum F3F

I'm proud and quite happy to say, that finally the Quantum F3F should be alive soon !

It has been a long project since the beginning, project which has nearly died when the initiator and manufacturer just abandonned the design team "in the middle of the river". But after all the effort Dirk Pflug, Gian Marco Occhibove and I put in this project, we just couldn't let it die so we found another manufacturer (ISM), much more serious this time, and resumed the project by revisiting the CAD drawings, doing some changes here and there to help manufacturing, then start milling.

Molds are now finished and the first prototype should be ready beginning of 2018. The time to build it and maiden it, and I will keep you informed and share my first impressions.

The Quantum has been designed only with F3F in mind, starting from an aerodynamic study about optimum turn radius vs plane weight/wind/flight time/Cz/Cx/etc ... 

What has been considered during the design is:

  1. Turn radius versus Wind speed
  2. Turn radius versus plane weight
  3. Turn radius versus initial entry speed
  4. Relative speed/air and Re
  5. Cz in straight line
  6. Cz during the turn
  7. What pourcentage of the time is spent in the turn

From this we could identify and optimize for a certain Cz - Flight Regime, and target the ideal thickness and camber. This allowed us to obtained the necessary requirements to design the section that Dirk then created especially for the Quantum. Wing planform is a pure elliptical lift wing, with a 2.98m winspan and 15.7 aspect ratio. We payed attention to the wing-fuselage and tail-fuselage junctions to reduce the drag with a dedicated root airfoil.

Here are the main data:
  • Wingspan: 2980mm
  • Length: 1465mm
  • Wing area: 55,6 dm²
  • FAI Wing Area: 61,0 dm²
  • Empty Weight: 2,2kg
  • Empty Wing Loading: 39,6 g/dm²
  • Max FAI Flying weight: 4575gr
  • Aspect Ratio: 15,74

The Ballast compartiments in the wings and in the joiner allow to incrementally increase the flying weight up to the max FAI wing loading of 75gr/dm2 without moving the CoG of the plane, so no need to add or remove balance lead in the nose. Also the maximum weight can be achieved without using very expensive tungsten slugs, brass being enough.

I also prepared a simple color scheme proposal that will be available is different color combination (comments are welcome).

You will easily understand that I'm very excited to receive the first prototype and fly it to see how it performs. I'm like a child ... and I have even prepared the 3D printed spacers file to go with the ballast ;)

Ivan Sanda Models will manufacture and sell the Quantum F3F. But please be patient and give us some time to fly the model first and do adjustments if necessary.

F3F season 2018 will be definitively very interresting and challenging for me !

Stay tuned !

Tuesday, January 9, 2018

The perfect F3F slope ?

It is funny to realize that your mind is always polluted by your addiction to slope soaring as soon as you see something that could look like a usable slope :) ...

This week-end, I was in the very south of France (Camargue) where the largest salt production field of Europe is located. Visiting the production fields I could see these nice salt mountains (called "Camel". each of them correspond to a one year of production = average 300 000 tons each), 20m high, more than 100 meters long ;) and exposed to the mistral wind ...
However maybe be too much salty for our material (corosive).

Should I start my detoxification treatment as soon as possible ? :)

JR Propo went bankruptcy

Sad news from Japan, JR Propo went bankruptcy on December 26. Even if the press release is not declaring that the brand will disappear, we all know that this means the futur of JR is very uncertain.

I have been a team JR pilot from 2012 to 2014. I still believe they have the best 2.4 protocol of he market, combining the best of the 2 worlds of frequency hopping and spread spectrum. Even if their radio hardware was very good, the firmware was not at the level of the best brand in term of flexibility and mixing.

Anyway, we will watch carefully what happens to them in the coming months. I sincerely hope they will survive and resuscitate !

Digital CG balancer

A good F3F competition plane deserves a good CoG setting, which requires the appropriate tool :) !

After testing and explaining the concept with 2 kitchen scales few months ago, and needing an excel spreadheet to obtain the CoG value, I wanted to reach the next level, and use one of the numerous digital CoG tools available on the market. Initially, I wanted to build mine and I had even printed all parts. But, I have too many thing in parallel, so I abandonned after this step, and ordered one when I saw this version, that is foldable, and personnalized ;) !
I just need to add some soft pad or rubber pad and it will be ready.

Many thanks to Kolosun Leung, and also thank you to the designer for sharing his work.

Sunday, January 7, 2018

First flights of 2018 !

Yesterday, I went with 2 clubmates (Joël and Pierre) to Quincieu as the forecast was very good: 12° and a 30 to 40 mk/h wind allowed us to fly all the afternoon. The wind start to die around 4pm, so we finished the session flying with AHIs.

Some pictures below.

Quantum update !

The Quantum n°001 is out of the moulds !!!!! Remain the cut ot the flaps/ailerons. It should land at its new home end of next week :) . S...