The Nelly

John Barnes

Or Highlight 1.8, or Omega E in the US. A 1.8m span, 5 function lightweight electric soarer for Speed 400 motors and beyond. At least the bare airframe is lightweight, mine tipping the scales at an interesting 9.6 ounces.

Mine flies like a dream straight off the board (at 34ozs), and it was fun hunting down TwinJets at the Hazlehead event. It also handled the very windy Saturday conditions with authority. I'm tickled pink with it.

What you get for £99 is a glass fuselage, composite D-box, open bay, film covered two piece bolt-on wing with full-span ailerons, and a pair of V tail halves. That's it. There is no fittings kit and no instructions with the model from SoarHigh, so it requires some experience to see it through to completion. These items are not provided by the manufacturer.

As I generally find it desirable, often essential to make up my own fittings kit when completing a model, the lack of these items wasn't a problem. The absence of a balance point (CG) for the model was an annoyance, although a US test report on this model gave some useful start-point setup tips.

The quality of the parts is excellent, but be warned. The impressively light V tail is foam with a very thin glass skin over it. While this form of construction is more than tough enough to handle in-flight aerodynamic loads, it is also incredibly easily dented. Dents are permanent, well mine are, and a reminder to everyone who sees it what a clumsy git handled it! My first error was forgetting to cut my fingernails before handling these items. My second was not taking the time to make up a protective transport bag for the tail before whizzing off to Hazlehead. On the journey in, a seat belt was laid on it to keep it in place. That's where the Britax logo on the tail has come from Rats...!

My build philosophy goes along the line of that if something can be accessed and removed for repairs, it'll never have to be. If it's glued in place or built-in, it'll break or need repairing. So I haven't glued in servos and I've made a removable V tail. But don't do this if you want the lightest model possible!

Lightness wasn't top of my list of priorities in completing this model, although the airframe weight after servo installation, fuselage reinforcement for a 100A+ motor option and heavy tail attachment system (two 3x25mm steel bolts) was still sub 13ozs. The reason for the overkill in tail attachment bolts was to get some weight at the back of the airframe so part of the battery pack would be forward of the TE!

I've used four Ripmax SD150 servos to drive everything, partly because they are just thin enough to go into the wings below rib height and partly because I like the side mounting lug option which they come with, and mainly because it's all the shop had in stock at the time! I have to say that to me the SD150s looked too small for driving the large, very light ailerons when at higher flying speeds, but so far so good. There's no sound of flutter in power off dives yet. As to longevity with this servo, with only about 2 hrs of air time on them at the time of writing it's too early to say. The control surface servo hook-ups are slop-free at present, so regular checks will reveal the onset of free play in any of the servo gear trains, at which point it'll be time to renew it.

The Gods? Well, I'm pretty sure that someone watches over me because my life has been riddled with lucky breaks, like, um, joining ADS. A little tale to demonstrate this fact.

Mr Robertson kindly offered to come and assist with the test flight day at my local field, so Derek and I duly met up on a sunny, breezy day. As part of the prep work for the day, I'd been so impressed with the performance of the little 1200 nicad cells that I'd made up a pack of 8 for Derek to try in his TwinJet, reason being that the 1200 pack at10oz weighed about half what the 8 cell 3300 NiMh pack weighed that Derek was using in the model; a difference of 25% in the model's weight.

Models assembled, Derek decided to try the TwinJet first. The Nelly was plonked in the grass, soaking up the sunshine for the next 20 minutes while Derek discovered that control throws for much lighter TJs can be handsomely reduced. As this was obviously an in-flight discovery, rapid on-the-job training was a mandatory exercise.

Now the Nelly's turn, where a function check before heaving it away revealed that both ailerons had jammed in their wing recesses at the tip end thanks to the afternoon sunshine. I'd been impressed with the closeness of fit of the ailerons in the workshop and haven't experienced this heating effect before on any model. 10 minutes work with a scalpel had both ailerons working freely. And they'd cool off in flight of course.

A clean launch, the model accelerating away straight as an arrow. A touch of 'up' to clear the trees, which rotated the model to vertical, where it continued for the next few seconds until it was high enough to perform exploratory handling checks. A touch of down trim and a whisker of aileron trim and she just cruised sedately along like a trainer. Another climb to height, more fooling around, and another, and another... Later analysis of the onboard altitude logger (LOLO) results - also being tried for the first time - showed that I enjoyed eleven climbs to height during the first flight. Initial climb rate was 2500ft/minute, dropping to 1300ft/minute as the throttle timer approached the 2 minute mark. I landed before the BEC cut-out activated because the model had become increasingly erratic in its control behaviour.

The first landing was interesting. The ailerons were set-up to reflex up together for glide path control. Activating this function on the landing approach caused an attempt to fast roll, unexpected when both surfaces deflect by the same amount. Only this time they hadn't. One aileron was seized in its tip recess again. So much for cooling off during flight. Scalpel, nurse! The field surgery took the clearance to about 1mm or so, and no jamming occurred during subsequent flights where the reflexed aileron trick worked a treat for landings, the 2nd flight coming to rest close to our toes.

If Derek hadn't been there and flown first, the poor old Nelly may not have survived its first flight, the almost complete absence of dihedral requiring the model to be flown most of the time. If it hadn't been sunny, I'd have been in blissful ignorance of the problem, waiting for the first hint of sunshine to pounce. And if I had wrecked it, by the time the bits were back in the shop for autopsy the ailerons would have cooled and the problem never been discovered. How lucky can one get? Thank you, God of Soarers and Derek, of course, now where were we...

Interference. With the Rx as far back as it will go the aerial was taken out of the fuz side at that point, taped part way down the fuselage and left to dangle. On its first flight the Nelly suffered the odd power-OFF glitch. On its second flight the glitching became more pronounced. For the third flight, the aerial was untaped from the fuselage side and routed directly to the tip of the V tail to get it as far from the fuselage as possible. This flight was glitch-free.

At Hazlehead, during the one flight on the blustery Saturday, there were again signs of the odd glitch, the motor kicking in gently on the glide as well. Sunday's flights turned out to be glitch-free. Mmm? I've subsequently discussed this matter with a few folk and have been advised that some Jeti receivers aren't quite as good as others. At Hazlehead, ever-helpful Jack Fisher suggested I try one of the new Schulze units specifically designed for electric flight. Not only that, he had an 8ch one with him for me to try! Good on yer, Jack.

I haven't had a chance to try it in the Nelly yet, but was talking to Andy Lewis soon after about his Pike Plus (F3J soarer) experiences when Andy mentioned that he'd changed the Rx in his Pike + to a Schulze 8ch unit. Andy hadn't been suffering any flight range problems with the old Rx, but with the Schulze in place his Tx aerial-off range check distance has gone from 2.5ft to 25ft! (Tranny is a Mpx 3030). Reason for the change in Rx is that the Schulze apparently has very good interference handling capabilities. Anybody in the club have experience with these units they'd like to share?

The Nelly after six flights

1. Reflexed aileron landings are done tail-low or horizontal at best (well, that's what mine have been so far). This has resulted in the underside of the V tail, very close to the ground anyway with the super-slim rear end of the fuselage, being damaged by contact with grass tufts, weeds, etc, despite the fact that all landings have been gentle ones. The damage is in the form of scratches and creases in the glass skin. It is this skin which gives the weigh nothing foam tail 100% of its strength, so an early modification will be to bond 2 thou carbon plate to the entire underside as a sump shield, the few grams well-worth the protection and associated in-flight peace of mind. This problem won't occur if your flying site is smooth, very short grass. Mine isn't. I'll pass this observation on to Guy to discuss with the manufacturer because the tail as-is has to be handled so carefully to avoid damage anyway.

2. The model is an absolute hoot to fly despite the fact that I haven't yet had time to spend harmonising controls or optimising the CG. At 34oz it has a wide speed range but can be slowed to a perfectly mannered crawl without a hint of dropping a wing or stalling. I fitted two servos to get rudder control, but apart from testing that the rudder actually waggles the fuz from side-to-side I haven't used it as a control yet, finding that turns can be made very smoothly without it, so the ship will happily operate on ailerons and elevator alone, saving the cost, weight and space of the extra servo.

The roll rate is pretty sedate and barrelly, loops rapid and consistent, but inverted flight requires full down elevator - which is quite a lot on my set-up - to hold it level, a sure sign that the CG can come back a bit. I haven't tried aerobatics under power yet so don't know if it'll knife-edge loop, but it'll certainly hover!

The least efficient, but most fun way to gain height is to do it with the fuselage vertical, and you can really only do that when it's pretty calm. On the very windy flight at Hazlehead, the wind was whistling over the tall tree line in front of us. The fuz angle was held at 45-50 degrees in the climb while the model ascended almost vertically, aided by the slope lift from the trees, all of which led to a much faster climb rate than previously experienced. Big grin stuff!

Verdict. A versatile, elegant, excellent design with terrific flight performance on modest power inputs. Highly recommended.