Evening all.

I have recently bought a Vladimir's model Graphite 2E kit from Neil at www.hyperflight.co.uk, I thought this would make a nice build thread, so here goes.  I ordered the kit because I have been hankering after a bigger electric glider for a while now, and I had the money spare, so why not?!

The Graphite 2E is a 3.1m, all moulded "electric hotliner" and should be a very capable glider for pretty much all the types of flying I intend to do.  I have gone for the Glass layup for now, and this sports a very nicely set of moulded components.  Details of the construction can be found on the Hyperflight website.  Interestingly, the fuselage is a kevlar moulding, so it will be perfect for a 2.4GHz install

The kit arrived in very sturdy box, and had been packed very carefully to avoid transit damage, so top marks to Neil for doing that!  The quality of the moulded parts, is simply outstanding.  All the surfaces a free from blemishes, and all the seams are nice and smooth, even and neat.  I chose a yellow kit with a red underside, and wingtips, and it looks very smart.  The wing is a 3 piece item, a centre section that bolts to the fuselage and houses the bottom hinged flaps (2 servos), and two wing tips that houses the bottom driven ailerons.  The control surfaces have very smart little carbon gap seals too, which is nice.  There are moulded in recesses for servo covers, and carbon skin reinforcements moulded in to attach the servo mounts to.  Incidentally, I'll be using the little moulded servo frames in the wing.

The wing parts are held together with a pair of very sturdy looking solid carbon joiners, and the fit in the sockets is nice and snug, with no apparent play at all.  As I chose the cross tail variant, the fin has a mounting system for an all moving tail, which looks very well engineered.  The pivot is nice and stiff, and the control linkage is a neat little moulded carbon affair.  The rudder and AMT servos will fit in a opening in the tail, which is also reinforced with carbon.

The front end of the fuselage is a removable nose cone, and this is sized to fit a 600 sized motor.  It also has a neat carbon platform to mount the battery pack(s) on, and a removable hatch to access the speed controller, and motor (and most importantly, the final battery connection!).  It slots into the main fuselage, and is held in with a single 3mm bolt.  I'm intending to fit a Hacker B50 11L motor coupled to a 6.7:1 gearbox.  It fits nicely in the nosecone, and just needs the mounting plate drilling to suit.  I'm not entirely sure on the battery/prop combo yet, but the motor is going to be well suited to around a 6s lipo setup, pulling around 60A or so.  I'm aiming for "adequate" power

So far, I am VERY impressed at this kit.  The parts are of excellent quality, and the accessories are of good quality, and seem to be very complete too.  That's it for now, here's some pictures to begin with.  I'll update the thread when I get a moment, but so far, the wing install is nearly done   If anyone wants to see any specific pictures, just shout!

Cheers
Andy

Hi folks,

I've been on holiday for a week or so, so no real updates to speak of.  I've weighed most of the parts I will be using to get a feel for the all up weight, and so I can start to spec the power system with a little more confidence.

Fuselage = 195g
Nose cone = 95g
Horizontal Stabiliser (both halves weighed as one) = 70g
Wing tip panels (pair) = 450g
wing centre section = 630g
Servos (futaba s3150) = 25g each - 6 off = 150g
accessories (linkages, joiners, bolts etc) = 100g
Rx (Spektrum AR9000) = 15g
Hacker B50 11L motor plus 6.7:1 gearbox = 315g

So, barring the wiring loom, batteries and rx power supply (or rx battery) and any glue used, the weight is going to come in at around 2.02kg (~4.5lb).  so, allowing approximately 500g (~lb) for a flight battery and wiring etc, and I should be looking at a 2.5kg all up weight.

I'll be looking to run the motor on either a 6s or 9s lipo pack (made up of 3s packs in series so I can use them in other models!).  I will then choose a prop that works with the hacker motor to get the current level (and therefore input power) up to the level I am after.  I belevie that for "adequate" performance in terms of climb rate and speed, I shoul dbe aiming for in excess of 200w/lb, so that means I am looking at at least 1kw.  On a 6s pack, that equates to a current draw of around 52A (assuming a loaded voltage of 3.2v per cell).  On a 9s pack, that equates to around 35A, which is easily acheivable with 2100mAh rated cells....

I'll try and get some pictures up of the progress later this week.  In the meantime, if anyone knows of a good supplier for big folding props that can handle this sort of power level, I'm all ears!

Cheers
Andy

Doh!  I've only just realised that the post before had no pictures attached for some reason...  Should be sorted now though!

Next up was finishing the wing wiring loom, and cutting a hole for the connector in the wing centre panel.  I'm using the Multiplex 6 pin connectors to join the wing wiring to the fuselage, and the same connectors to connect the outboard panels to the centre panel.  Soldering the main connector was strightforward.  I grouped all the +ve connections at one end, the -ve at the other.  The four signal wires then use the middle pins.  These connections were given a good check (to make sure the soldered joint was sound) before potting the lot in some epoxy/microballoons to act as a strain releif.

The next job was to cut a hole in the centre of the wing panel to feed the wiring through.  The aperture does not need to be huge, so I cut a 20x10mm hole with rounded edges using a dremel and a half round file.  The rounded corners should help minimise any stress crack appearing.  The location of the cutout is aft of the spar (see photo).

I will put a bit of heatshring tubing over the wires where they are in contact with the wing surface, to minimise the risk of chafing.  With the wiring fed through the wing, the outer panel connector was soldered in place (and potted as per the main connector) and finally the outboard panel connector soldered in place too.

All the connectors have been left "floating" mainly so that the wiring loom can easily be replaced if required.

The next step I shall tackle, is installing the servos in the main fuselage, and then installing the receiver, along with the wiring to the wing connector.  That will allow me to install the wing servos, setup the correct centrepoints and endpoints using my radio, and then install the control surface linkages/fairings.

Cheers
Andy

Me too!  Fingers crossed it will be ready for a maiden at the aerotow this weekend.  It probably won't be at full power (not ordered the packs yet), but I'm sure it will fly on the packs I already have, just not as much climb as I have got planned!

I've been having a ponder this morning on the way in to work, about the receiver install.  I'm going to be using a Spektrum Ar9000 with two remotes.  The main recevier is going in the fuselage, just aft of the wing seat.  one, or possibly two of the remote receivers are going in the wing centre panel, just outboard of the flap servos.  I can't decide whether it would be worth popping one of the remotes in the tail, and do my best to keep it clear of the AMT linkage though.

Maybe I should do both, and see what performs the best?!

Cheers
Andy

Evening all.

I've done a bit more work on the Graphite, and it is really starting to take shape now.  I'm still really impressed at the quality of this kit too!  So far I only have a couple of things that are not quite perfect, but I'll save them until the end

I spent a fair bit of time perfecting the flap linkages, and with a bit of help from the guys on this forum, I now have a flap that can attain the 6-7mm up required, and almost 80° down travel, using the full range of servo movement.  It did require the grinding of the clevis keeper back a bit to clear the horn at full travel, but it works a treat!  The best bit is that I have managed to end up with around 0.5mm of play with a bit of load on the flaps and ailerons.  Apparently this is pretty good All the servos were set up to get the linakes and travel as close to equal mechanically.  Some minor subtrim will be required as always though, hopefully it will be minimal though.

I've masking taped the servo covers in place, after trimming them to size and sanding the edges to remove roughness.  The flap servo covers have a moulded in bump, which is not really needed, as I have managed to install the linkage within the wing entirely.  This is probably only possible because I used quite thin servos (S3150).  Annoyingly the covers provided for the flap linkage exit on the top surface of the wing, are coloured red.  The wing surface is yellow, so I think a bit of spray paint should sort that out

I've also done a bit more wiring, making up the harness to link the receiver to the wing connector.  This is long enough to allow the receiver to positioned well forward, or aft of the wing connector, depending on the final positions of the equipment.  I'm probably going to install it (the receiver) aft of the wing seat, to provide maximum room for the battery packs.  The othe bit of wiring I have done, is make up a pair of extension leads for the tail servos.  These are around 36" long, and are held in the boom using a couple of EPP foam plugs that are slit for the wiring to slot into, and then pushed down the boom.

More pictures in the next post

Cheers
Andy

Evening folks.

I've spent a couple of hours today sorting out the motor mounting arrangements.  This required four M3 clearance holes cutting on a 25mm PCD to suit the Hacker motor and gearbox, and the centre hole opening out to 17.5mm diameter.  To do this accurately, I drew a template up in Solidworks, and printed it out,  This was then cut out, and glued to the motor mounting plate using some pva glue.

It was then a simple job to drill some pilot holes, followed by opening the holes out using a 3mm drill (cutting holes in fibreglass using standard drillbits tend to give slightly oversize holes, perfect for clearance holes!), and finally routing the centre hole out using a dremel and a routing bit.

These holes were then deburred, and checked for the correct size, before applying a smear of thin CA to the edges to seal them, and prevent splits etc.  The motor needed some connectors putting on it, so I soldered some 3.5mm gold bullet connectors to it.  This will allow easy changes of either the motor or the ESC.  I did wonder if 3.5mm gold connectors would be man enough for a powerful setup, we'll have to see how they go though.

The motor was installed using some M3x8mm stainless socket head screws and washers.  I need to put a dab of threadlock on these to make sure they don't vibrate loose, but I have run out of the tamiya type stuff I prefer to use in this sort of situation (i.e. externally).  The motor fits nicely, but popping the spinner (38mm aeronaut one) on reveals a 3mm gap.  I may need to grind a couple of mm off the gearbox output shaft to remedy this.

You can see from the picture that there is bags of room in the nose cone, even with a big motor, gearbox and ESC (Phoenix 80 at the moment).  It is going to be a tight sequeeze getting a decent sized pack in the nose cone/fuselage, but it should be ideal for a number of smaller packs.

The other thing I have done is installed the two Spektrum remote receivers (well, JR ones) in the wing.  No photos for this, as it is incredibly difficult to get pictures inside the wing.  They are mounted just outboard of the Flap servos (using double sided foam tape), and have extension leads running to the hole in the centre of the centre wing panel.  This is then terminated in a 6 pin multiplex plug, and there is a socket on the fuselage side too.  All  pretty simple stuff really, and as the wing is glass fibre, it should work a treat.

The only jobs left now, are to install the Rx, and sort out whether I can use my existing 3s 2100mAh packs connected in series, or whether I need to invest in some more, slightly bigger packs!  I also need to decide how to power the receiver and servos.  AS I have 6 digital servos on board, I don't want to underspec the power supply, so I am thinking that a couple of BECs in parallel might do the trick at the moment, taking power from the main pack.

Before I decide though, I'm going to assemble airframe fully, and see where the CG is at.  As the motor is on the large side, I have a feeling it may turn out to be a bit nose heavy, in which case a RX pack stuffed down the tailboom will work nicely

Cheers
Andy

Right, having done a few tests this afternoon, and heard from various people, it seems the Futaba S3150 servos pull less than 1A when stalled at 5v.  That means a CC-BEC running off a 3s pack will power the radio gear nicely (rated up to 7A continuous apparently!).  I've just ordered a couple anyway.

As the weather wasn't too bad when I got in from a flying session this afternoon (been sloping on the Orme, fantastic!), I assembled the Graphite in the back garden.  It is surprising how a 3m glider eats up the space in the back garden!  Everything went together easily, the wingjoiners being a nice snug fit.  I'll probably give them a few coats of wax polish, just to max sure they don't stick at all.

The Centre of gravity (with no batteries, rx or prop onboard) is around 25mm behind the recommended position of 110mm from the leading edge.  Once the receiver is installed, and the spinner/prop is installed, it is still going to be in this position, so I think a heavy battery pack is going to require a bit of tail weight unfortunately.  I may look at swapping the Hacker B50 11L motor for one of the B50 s types, to save a couple of ounces in the nose.  This would mean a slightly lower power handling capability, but loooking at the specs, it shouldn't be too much of an issue.

The all up weight (minus rx, prop and batteries) is currently coming in at  2116g  and that is made up of:

Wing centre panel - 704g
Wing tip panels - left - 298g, right - 295g total - 593g (inc wing joiners)
Horizontal stabiliser (both halves) - 56g
Fuselage (including nose cone) - 749g

So the weight has crept up a bit, but not much.  That is not far of my estimate, and not bad considering I have used heavy duty wiring everywhere.

The other thing I have done tonight, is fit all the servo covers and  linkage shrouds.  Dead easy with a roll of diamond tape, a sharp pair of scissors, and some alcohol to degrease the surfaces.  It is a bit difficult to take a picture of diamond tape though, as it is so clear!  The only tricky bit, was trimming the flap linkage shrouds that are fitted to the wing upper surface.  Nothing a bit of sanding couldn't sort out though!  Oh, the other thing I did, was to put a layer of diamond tape down on the wing seat.  This is just to try and minimise any scratching in that area.  I'm not sure if it will be worthwhile or not, but we'll see.

The next job is to get the receiver fitted, and the motor test run, to see how much juice it needs for the various props I have.  After that it is just a case of decide on the battery configuration, wire in the CC-Bec, and juggle things around to get the CG right.  Not far to go now!

Cheers
Andy

WEll, it's ready for a maiden!  The power system has been tested on the bench with a 6s 2150mAh pack (made up of two 3s packs in series), and a 16x10" prop.  This is pulling a shade over 800Watts at around about 40 amps or so.  It is pushing the batteries quite hard, but it should be okay for short bursts of power to get to height.  The batteries result in a CG that is a little bit further forward than the manual states (manual says 108-112mm back fromt he Leading edge, I currently have it set at 102mm back).  As the motor is not particularly stressed running at 800Watts, I may look at dropping down to a short can B50 to save a couple of ounces in the nose.  We'll see what the flight performance is like first though!

I've been setting my transmitter up too, and now have everything running nice and smoothly.  I can reflex the flaps slighty for speed, and drop them a few degrees for thermalling on one slider, and on another slider I have some rather natty crow brakes programmed in for the landing too...

I'm off to the field in a bit to get some assembled shots, do some range tests, and see how it flies!

Pictures (and maybe a video!) later...

Cheers
Andy

Well, it flew, and it flew really nicely too!  I now have a new favourite plane, and I honestly can't remember being this pleased with a model plane since I managed my first "crash free" flight of an electric Zagi when I was learning to fly! 

The take off was a non event really, the power available made it a doddle.  The climbout was nice and, er, vertical, and it seemed to impress everyone watching so that must be a good thing!  I have no idea how much height I was getting from a 10 second motor burn, but it was good for around 3 min of gliding before losing about half the original altitude.  I'll have to get the altimeter wired up to see whats going on.

I was surprised at how quickly it covered ground when cruising around, but no where near as surprised at how well the Graphite slowed up when I dropped the flaps by about 10mm or so!  I think when I get the full span camber control set up correctly, it is going to be brilliant at hanging around in areas of lift, but speed up nicely to cover ground when required.  There was a small pitching up moment with flaps, so a bit of mixing will be needed there.

Crow brakes were good, although I was getting a fairly big pitch up when the flaps start to drop past around 40°.  The roll was quite barrelly too, so a bit more differential might be needed I think.

The forward centre of gravity seemed to have no huge effect on the performance when the right way up, so I think I'll leave it where it is for now.  Inverted flight needed a smallish amount of up, so perhaps it can come back as per the instructions??  Something to play around with methinks!

I managed to squeeze my datalogger in the nose too, which revealed some interesting readings of the maiden flight (see attached pic).  Maximum power a shade over 1kW with freshly charged batteries, and a 20 minute flight taking around 1200mAh out of the packs.  As there was naff all lift around, and I was "exploring the performance envelope" somewhat, I expect 45 minute flights with no lift around should be the order of the day!  Add a bit of thermal activity in, and the flights should be as long as I can look up for!

All in all, I'm well pleased!  Slightly less pleased with my camera batteries lasting less than 20 minutes though, meaning no pictures, and no video as yet...  Maybe tomorrow!

Cheers
Andy

well, all's well that ends well.  Should be a great model. good all rounder with that wing. especially if you do the glider fuse.  plenty of ballast and you'll be up the orme tearing it up.  get her on the slope with some lead in and really see what that wing can produce. 

funny how that pitch up happens eh?  You probably need cactus et al to tell you how to set it up (even though they've never flown anything like it).

yes the supra.  Good old Neil has worked his charms on your credit card.  as a pure glider the supra is pretty light. then i am talking from a slopers perspective - it's not a model i would buy for that reason if i already had a graphite.  they are nice though.  I've had a look at a couple of Neil's. 

Hey folks,

I've had another hours worth of air time with the Graphite 2E today, this time with an altimeter sensor onboard too!  The weather conditions yesterday were almost perfect (no wind, nice and warm with plenty of small lift bubbles around), whereas today, there was a 15mph breeze with naff all lift.  Despite the breeze, the Graphite penetrates very well, and with a bit of flap, it sort of hangs in the air, which is brilliant for picking up the odd bit of lift passing through.

Landing was a bit tricky though, mainly because of low level turbulence.  It caught me out on one occasion, and I now have a slight dent in the leading edge of the centre wing panel, about 5mm wide, where The landing approach was cut short.  As luck would have it, I managed to slide in, stopping by hitting an electric fence post that was lying on the ground.  Nothing serious, just annoying cosmetic damage

Looking at the altimeter plot (ignore the big upward spikes, must be noise or something), you can see the climbs are nice and brisk, and I even managed to pick up a bit of lift to get a 12 minute glide from a 15.75 second motor burn.  The same motor burn was averaging around 775 watts (input), and resulted in a 13.2m/s climb rate, topping out at 209m.  In old money that is a 2600 feet per minute climbrate, which is alright I suppose, especially when it is straight up!

Cheers
Andy