Sloping Off - September 2005
Fournier 4B Quarter Scale Motor-Glider
by Terry Antell
Occasionally in life we all have the chance to fly something new, to us that is. My opportunity came during the Spring of this year. I was looking at other club websites, particularly the ‘For Sale’ sections, when I happened upon the Fournier on the Thames Valley Silent Flyers or TVSF. This 1/4 scale beauty does need a runway to get into the air as it weighs almost 10lbs.
Details: 3 metre wing span (2 part wing), quite a large bulky fuselage and a fixed single wheel undercarriage, also two wing tip wheels (to keep the wing from the tarmac!)
It was built from a Mick Reeves plan pack and assembled as an electric powered model. The 2 A4 sheets of instructions suggest a .40 to .60 2 stroke glow motor!
It came with servos ready installed. One for each aileron, one for each airbrake, plus one for rudder and another for elevator. Naturally, I spoke to John Emms at Puffin Models. Powered gliders use quite small propellers so a powerful higher revving electric motor would be required. I bought a Mega (in runner) 22/45/3E, a Jeti 70 opto speed controller, a 14 cell Nimh 3300mah pack and a 12 x 8 fixed elec prop.
The undercarriage presented a problem. I could not make a retract work as there isn’t room cos the battery packs use the allotted space! Problems are there to be overcome, are they not? I made a single wheel undercarriage using a .60 size engine mount. The 3.25in wheel fitted a treat.
Its first flight was off Barton cliff top. A hand launch was decided upon. Not the right decision, I can tell you. She went almost down to the beach before commencing a sedate climb out, (insuffient air speed) I did the stall test and dive, which told me the C of G was too far back. This was followed by a loop, inverted fly past and a roll, I mean Roooooooll. It took forever to right itself! The top brakes are effective, too!!!!!
The landing was not a problem as I kept up the speed (air and ground speed).
I didn’t know where the C of G should be so emailed Mick Reeves. A swift reply was received, telling me it should be 3.25 to 4 inches back from the leading edge. Oooops, I had flown it with the point at 5.5 inches!!! (It’s now 3.5ins). The overall weight came out at a little under the prescribed amount, it being 10lbs.
I have since flown it from Stanpit on a quiet afternoon before the schools broke up. I’ve also flown it a couple of times from Beaulieu Airfield site.
The latest amendment has been to change the trailing tail wheel to a steerable one. The airbrakes were on a 3 position switch. I’ve now changed the channel for both servos which are now controlled via one of the two, side half rotary switches on my JR PCM9X Tx. I’ve also added a pilot. It’s a young looking shapely lady!!!
Thanks to David Enticott for the girlie.
