Monday, 22 September 2014

More Test Flying Aresti 108

Some more flying of the Aresti 108 at the Firle Beacon on the South Downs, East Sussex yesterday. It's fairly light wind around 15-20mph but occasionally thermic and no ballast was necessary. Much smaller hill than Bopeep and in fact the bowl was the poorer one as the hang gliders were using the best one! So this really is showing the big 108 doesn't need a massive hill/conditions.
Greg Lewis flew then Dave Woods had a go and well, you can see the results! Greg tells me he then had difficulty getting it back off Dave! Dave is a 'top' classic acrobatic pilot and he put the Aresti 108 through it's paces- enjoy! One of the characteristics of the Aresti 108 that has been commented on over and over that in the air it looks like it's flying slow. However pull the elevator and it does a tight loop, which you would not expect from that 'speed'. No doubt its a scale effect thing and it's actually going quite quick but the size just makes it look slower. So, the energy retention and needs a bit of adjusting too but of course this is what is making this plane so amazing to fly. It's graceful and still has plenty of oomp for manoeuvres.
Dave makes a tongue in check joke for James about the revised enlarged rudder still being too small, it's not but obviously Mr Woods wants to keep James on his toes! BTW, I'm told Dave never got out his own plane yesterday and Greg had to fly his Crossover because he could get another go with the Aresti 108!

Thursday, 18 September 2014

Aresti 108 video

The Aresti 108 flew yesterday at the Bopeep Hill in the downs near Lewes, East Sussex. Conditions were much better than the maiden just a few days ago and around 15-20mph. Only its 2nd outing it was flown by 5 pilots including Greg Lewis, who nonchalantly handed around the transmitter! Despite it’s size it’s actually very easy to fly with no vices. The energy retention just keeps it going and she looks beautiful carving big shapes. The roll rate is outstanding especially for a big plane and it was even ballasted up with 1kg of fuse provision (12 slugs of 19mm, ¾’’, 35mm long brass) making a total flying weight of approx 4.8kg. There’s approx another 1.4kg to go in the wings with a 610mm long 19mm round brass bar that wasn’t felt necessary.
Here it is, a very honest unadulterated raw video shot with Gro Pro on Greg’s head. You’ll get an idea of what it did but what isn’t conveyed so well is the sheer size and presence not only of the airframe but those loops and bunts are enormous!

The airframe shows no sign of stress, which is as well as the joiner and spars are enormous and because the wing is thick and has a broad chord, it’s not bendy or twisty. The fuse is also very strong especially along the boom fin juncture with a full carbon except for the canopy area.

Proto radio tray built mostly in 6mm ply
Production one will be moulded and factory fitted, but
same principle and will add a huge amount of strength
to the nose area.  
One of the features of the Aresti design is the 2 piece tail and elevator design. The tails are very firmly held in place and no wobbly tail plane as you’ll find in most all moving tail designs but more importantly pitch control needs very little deflection only +/-8mm with 40% expo. This all contributes to the energy retention and efficiency that the Aresti 108 is showing. Aside from the deep sides it’s actually a very clean design. Even with full size servos in the wing the covers are flush!    

It clearly doesn’t need a gale or epic hill to do this and looks so smooth it’s one of those rare planes that can make your flying look better! The guys had a blast, what more could we have asked for so early on in prototype testing. I have a feeling we are not far off, just minor installation details to make the build pain free and linkages optimised. This is going to be very easy to put together and thoroughly complete!

Aresti family!

Monday, 15 September 2014

Aresti 108 maidened!

Aresti 108 prototype
Most UK slope fliers will have bemoaned the complete lack of wind for virtually 2 weeks as we have been sat under high pressure- very unusual for the time of year and frustrating indeed, as we had the new Aresti 108 prototype ready to fly. So seeing that there was an end in the conditions yesterday we dashed across to the east coast of Yorkshire, at Reighton Sands and the prototype was finally maidened! Wind was light, only around 8-10mph but enough to prevent us from having enough doubt or common sense (!) from lobbing off the 3.8kg prototype for it’s first ever flight. However, CG was set at 130mm, about 6mm (scaled up) in front of the position that we fly the Aresti 2m, which was our only attempt at any precautions!
Big plane about to be launched, like a 1/4 scale but with low aspect ratio wings
The elation as this big bird soared effortlessly away was blatantly felt by all, except it seemed by the Aresti 108! She just majestically carved through the sky in a rock steady path. Big planes just sit in the air so steadily, it had presence and cut through the air with such authority. No twitchiness, no bumpiness just creamy smooth progress. Sure we could have done with much stronger conditions to show case its potential but after so much anticipation it was enough to see vindication for building such a large acrobatic slope plane. The size just brings another element, doubts about being too big for anything other than flying in the Alps was immediately dispelled. It doesn’t fly slower but the scale effect makes it look as though it does and even on the coastal hill flown yesterday you could see that it’s going to work on a lot of our hills!

It was also satisfying that the trims were left alone and no changes made- even the thermal setting seemed about right as the camber really made a difference to height gained. This was about the same ceiling as anything else flown before. A dive to check the feel of the CG and yes it was nose heavy which of course is no bad thing for a maiden flight. The roll rate was good but the differential needed a tweak and the elevator with couple camber and reflex was a tad too much, other than that the first ever flight. piloted by Greg Lewis, was exactly what we hoped for. It’s just beautiful in the air with such presence that got everybody’s attention as unusually the slope was quite busy- must be the break in the weather that got fliers out to the East Coast!  
Low pass for the camera!

This is a plane that has real presence in the air!
Next it was my turn for a flight and we moved further round to the North to get a better vantage of the light lift. 
Greg Lewis holding- this shows a perspective of the size of this model as we walk towards a more northerly spot launch
Now I’m just a competent, average flier and definitely no acrobatic pilot but even in my hands it made my flying look good. It was so smooth which now made my big cheesy grin even bigger! It just felt so steady and coming close in, it whooshed past with a sound unmistakable that this is indeed a big plane. It seemed to just plough through and if anything, easier to fly than the smaller Schwing E and Aresti 2m I’d been flying earlier. I had a Mobius cam strapped to my head to film the flight but regrettably in the anxious moments before my flight I had it pointing a little high so no great footage. 
However, even in the conditions we had which needed an efficient airframe, it could cover so much sky and cruise along with ease which considering it’s fully symmetrical section I didn’t expect quite so much efficient use of the lift available. I fly with the same transmitter as Greg (but a different mode hence the prototype was set up on 2 transmitters with slightly different throws) and consequently had slightly better settings for roll, although I had reduced elevator throws, discovered from the first flight. This was approx 8mm up and down.
A few tweaks to the programming!
As predicted for the forecast wind strength increased as we got later in the afternoon and Greg took the Aresti 108 up again for it’s 3rd and final flight of the day. 30g trimming weights were removed which put the big Aresti at the same cg as it’s smaller brother.  In addition the throws were altered in line with my settings. The inverted flying was now pretty bang on. Stall turns with rotation at the top from the massive rudder was impressively round and seemingly in one spot- which was very gratifying as much work had been done on this with 6cm (!) throw either way (30 degrees). One surprise was how tightly it could loop without getting upset. The diameter looking quite small indeed!
All in all, a dream of a first day’s flying that really could not have gone better. Overall the leaving impression was this plane has so much presence- it’s going to be a show stopper in better conditions, I’m sure and that’s exactly what an acrobatic plane should do! 

We shall be test flying at various slopes, building on the valuable information gained today. It might be near you! I keep you posted here, as we’ll also be bringing along the Aresti 2m, Carbon Schwing and new Electric Schwing hotliner prototypes.  

All prototypes- Schwing E on 6s, Aresti 2m and Aresti 108- fantastic days flying!

For those that want more info about the build of the prototype, here they are:

Servos 6 x Hitec HS5496MH, full size 20mm wide and HV, used on all surfaces, including Aero Tow release (well why not!) except elevator, which used a Graupner DES 448 BB, 10mm servo mounted in the fin and regulated with a MPX servo voltage regulator.
Fu-Fix bearing kit used on all servos (including rudder servo mounted in the canopy area) except Tow Release servo.
Battery is Thunder Power 2600mah 2s Rx lipo
Ballast in fuse is 12 of 19mm round, 35mm long brass slugs approx 1kg. Additionally 19mm round brass bar 610mm long in wings, 1.4kg. Total ballast provision is 2.4kg
Total ready to fly wt is 3.8kg and with full ballast 6.2kg.
Nose wt required to balance is approx 200g.

CG flown, 136mm from LE at root.  
Full size Hitecs in the nose, rear rudder servo even has a bearing kit using a 14mm arm for massive rudder throw. Front servo is for Aerotow release!!

Tuesday, 2 September 2014

Aresti 108 prototype

It's been a while, not only since the last time I made an entry but also for the Aresti 108 which I can now finally say has been born! It's at the Sloperacer workshops and busy getting it installed for it's first flight. The quality fit and finish for this huge, full carbon acrobat is definitely what you would call top notch 'EU quality'! Which shouldn't really be a surprise to us as our manufacturing partner is a renowned competition glider manufacturer in CZ. They have done a great job and all helps with the pride and excitement of seeing this project coming now nearing it's final stages.  It definitely deserves the accolade of being a flagship model for us and this is only the prototype! It's designed by Dr James Hammond and though I'm obviously biased, dare I say it's his best to date! I and many others have always wondered what a Hammond design could do if it was built by a top EU manufacturer. Well we won't have long to find out!
Even though it's a proto, it's beautifully made- simple stripe scheme for now but at least it isn't our usual 'white ghost' proto! 

It has some of the modifications from the 2m Aresti prototypes and so yes the rudder is enormous but then so is the whole plane, much bigger than you would expect for it's 108'' span. The pleasing thing though is that this prototype comes in at 2.7kg empty so reckoning on around 3.5kg ready to fly. To put this in perspective, I guess the X Models Stingray is a simlair size and aspect ratio. These are around 7kg empty! So we are really hoping for light wing performance too with the Aresti 108 someting I know a lot of acrobatic pilots have been asking for. However, there will be plenty of ballast provision with 20mm round tube in the wings and I'll be putting in 20mm tube in the fuse too. Aiming for around 2.4kg so approx 6kg fully laden. I'll guess we'll find out soon enough if this is going to be adequate!  
Did I mention it's full carbon? That's all the tail surfaces too, only the front nose section is glass for 2.4 purposes.

Massive joiner!
The joiner is 40mm x 20mm in section and over 1/2m long! After all it's a huge plane, let's see if the following pictures do it justice.
Yep, that's the chord!

Can't wait to get this flown! It's going to be a show stopper on the slopes!
The space for wing servos will allow full size 20mm thick all round but a bit of a squeeze in the aileron well so probably best with a midi 15-17mm servo.
Flap well about 25mm

Aileron about 20mm
The horn geometry and servo well positioning has been very well thought out and designed for flush covers
Servo wells opened up on LHS wing, note they are angled to be at 90 degrees to the hinge line- no binding here! 
Well we know how the 2m Aresti flies and this big Aresti prototype has ticked all the boxes in terms of weight, strength and most importantly quality. It's exciting times, stand by for maiden report!