Reviewed by: Barrie Purslow
After reading Martin Bell’s review of the Sprite Thermal E in Q&EFI I just had to have one. A few hundred pounds later and I had one. I was immediately impressed by the quality of the moulding. It is first class and the whole structure is incredibly light and so rigid.
I immediately set about installing the R/C gear using Hyperion HP-DS09AMD digital servos and my trusty Futaba 2.4 Gig 10C. The motor is a direct drive Mega 16/25/6 with a 10 x 6 prop. With a light motor and servos in the fin I was disappointed to find the C.G. was too far forward even with the 2200 3S Lipo shoved almost under the wing. I really didn’t want to add ballast so, after some thought, I cut over 2" off the nose! This brought the C.G. exactly into the middle of the allowable range. The only other problem was the neutral setting for the all-flying tail. An exchange of emails with Neil and Vladimir established that the it should be set parallel with the bottom of the fuselage tail boom.
Now all I had to do was wait for the worst winter in recent history to fade away and I was off to the nearest big hill. On the first flight, despite setting the all-flying tail to Vlad's instructions, the model was seriously over elevated, even full down trim was insufficient to fix it. A quick landing and some Sub Trim put that right and I was then able to enjoy a beautiful R/C glider with immaculate handling and an excellent speed range. On a blue day with virtually no hill lift but blue thermals it proved to be good at showing when it is in lift and is very easy to circle.
The C.G. felt right and this was confirmed by the dive test when it carried on without deviation when I removed my thumb from the elevator stick. The acceleration was quite impressive too for such a light model. A few runs of the motor gave a climb angle of about 40 degrees - more that enough for me in my post comp. era.
The landings were just fine although I hadn't set up full crow braking - only the flaps being used - it really needs the full monty as the braking effect of the flaps alone was rather poor even with almost 90° of deflection.
Is it worth all that money? - you bet!!
Barrie.
Reviewed by: Skip
Looking for a follow-on model to my lightweight 2m Pulsar I came across an article in QEFI (September 2009) by Martin Bell describing the 2m all-moulded Sprite-e. This sounded just the job for next season’s eSoaring! Martin wrote enthusiastically about the model’s quality, design and flying capabilities; it came from Vladimir’s Ukranian stable and was available from Neil at Hyperflight. All plus points in my book – so I ordered one in white and red. Martin was definitely correct - the model quality is absolutely superb. All the small components are included so you can start building immediately using the enclosed instructions along with Martin’s helpful QEFI article.
Up front I used one of the Hacker A20-6XL geared outrunners on a 14 x 10 folder with a TP Pro-lite 3S 2100mAh lipo via a Jeti Spin 44 controller. A very neat cranked 38mm Hyperflight spinner completed the installation up the sharp end after some trimming to fit the Aeronaut blades. Hyperion Atlas digital DS09AMD servos are used for rudder, elevator and ailerons, with the slightly thicker DS095FMDs for flaps. Getting the aileron and flap linkages set up correctly was definitely the most involved part of the build for me as this was my first moulded model with a 4-servo wing. Confidence was boosted by the RC Groups Sprite thread (www.rcgroups.com/forums/showthread.php?t=1042724?pa). In conjunction with an offset servo neutral I managed to obtain around 75-80 degrees of down flap. Just what the doctor ordered!
To make life more complicated I treated myself to a new Futaba 8FG 2.4GHz transmitter to control this wonderful beast, spending many a long dark winter evening trying to get to grips with all the new programming features. The templates supplied for the Sprite’s camber settings along with Martin’s notes were very helpful at this point. Eventually confusion receded and the snow melted about the same time. So off to the flying field wearing my best brown trousers!
Fortunately the maiden flight was something of an anti-climax. A CG at 93mm aft of the wing LE (requiring 15gm of tail weight) saw the Sprite climb away nicely transitioning to a fairly fast glide after cutting the motor. Switching into thermal mode slowed it down nicely, exhibiting well-controlled tighter and flatter turns, allowing me to follow two buzzards that appeared as if by magic at that point. Flicking into reflex mode produced a significantly increased speed to cover the sky much better than my Pulsar ever did. Deploying flaps brought the speed right down for a relatively easily-controlled nose-down descent back to earth for high-fives all round.
A couple of week’s flying has enabled me to explore the trims and mixes to learn more about the capabilities of this wonderful model. Moving the CG back a few mms has given a better balance for thermal hunting and I’m starting to seriously enjoy the qualities of the Sprite. No excuses now for turning in a poor competition performance!
Skip
