Luna E-V Warmliner

[Rory Gillies]

Hi Folks,

My first post on Model Flying, but having read many threads here for several years I thought it would be time to contribute! In fact it was when I was researching my latest project I found more information here than nearly anywhere else.

Having been a mainly scale flyer I was bitten by the glider bug earlier this year with a Radian Pro, followed by a Diamond D2500. Both great machines, both heavily modified for strength, and both great fun to fly. I live in Shetland which is very windy (hence the foamie strength mods), and although I've had the Radian Pro out in a force 6 it really is at the limit of flying being a "pleasurable" experience with a foam model!

I decided to build a composite warmliner for general purpose, flat field, coast and slope, and after several weeks of research I came down to a choice between a Mini Graphite E or Luna E-V. Both very similar in design, look and airfoil, but quite different in quality and price!

The Luna E-V won, and I'm currently waiting on several boxes of goodies "winging" their way to Shetland to start my winter project. I've gone for a Hyperion Gs3014-16 motor on 3S with 13x8 for warmlining and 12x6.5 for slope and general flying around. I'm using high torque low profile TGY778s on the wing and 306Gs on the tail, and it will be a full house affair with a 7008SB Rx and my14SG Tx.

The buid logs here on the Luna have been very helpful and will certainly keep me in the right direction on my first composite (plenty balsa and ply experience!). Just wondering if anyone else has the Luna E-V or even flown one?

I'll post some pics when the stuff starts to arrive

Cheers,

Rory

[simon barr]

Don't know the model, but welcome to the forum, and to the delights of gliding, and in particular slope soaring...

There can't be many modellers in Shetland are there?

[Rory Gillies]

Hi Simon, no, we're a rare breed up here! I'm actually in the process of trying to form a club, and have 26 "likes" on the Shetland Model Flyers FaceBook page which is a start. We intend to convene over the coming months in a location with liquid refreshments and get things started. The ultimate aim, apart from bringing like-minded folk together, is to secure a flying field and some sort of clubhouse or workshop.

Back to the Luna E-V, it's basically a Luna 2 with a V tail and spinny nose. Much of my soaring is over the sea, so I like the idea of a motor to get her back - we have cliffs with great lift that in certain points have sink that will quickly take you to the water! There's some great soaring sites here, and being an island I can always find a slope or cliff facing the wind. If there's even a light westerly I can keep my Diamond or Radian Pro up all day at The Knab, which happens to be a one minute wings-on walk from my front door (the neighbours don't bat an eyelid anymore with me walking out the house carrying the 2.5m span Diamond).

i chose the Luna E-V as I wanted a composite about the size of the Radian Pro that will fly in a wide range of conditions and survive landing in heather - it bites big chunks out of foam even with an almost backwards full crow landing! I also wanted to have a go at putting together a composite and choosing all the stuff I want to put in it. Both my Diamond and RP have very little of the supplied kit in it, in fact bar the motor there is nothing original in the Diamond. I fly these things in winds that they were never really designed for, and - reaching for the wooden table - never broken one yet in the air or landing. It came very close with the RP once when a big gust caught me about 1' off the ground when landing. She did a perfect loop in about the length of her fuse and plonked herself belly first on the ground - would have been cool if I meant it to happen

I'm not into the idea of hotliners, and from my scale days I tend to fly gracefully, preferring to soar around on the lift rather than tear up the sky and perform crazy aerobatics. And as old age doesn't come by itself, specifying out even the chunky Diamond is only about 500' due to my eyesight!

The first part of my project dropped through the letterbox today - the rear bearing plate for the motor! Well it's a start

Rory

[Steve Hargreaves - Moderator]

Sounds like you're well on the way to enjoying your new model Rory......

Welcome to the forum....

[David Ashby - Moderator]

Hi Rory and welcome.

Quite a few Luna threads on the forum here (pop the word in the search box) so they may help.

[simon barr]

Yes, Rory, the beauty of an island is, like you say, there is always an available slope. We can fly in virtually any wind direction here in Jersey...

[Rory Gillies]

Well she's arrived! Far better finish than I was expecting, not a single blemish on the gel coat and everything appears to line up perfectly on a quick dry layup. The Hyperion outrunner is going to be a tight fit, with less than 1mm clearance for the heat shrink where the wires exit, so I may cut a small slot in the fuse under the motor bell - that will add a wee bit of cooling as well.

Now that nearly everything I need is here I'm going to have to start making some decisions about the build. Wings or fuse first? And where to put the tail servos - I'm quite keen to go down the Mini G setup and put them under the wing, leaving plenty room up front. That would mean cutting a bigger opening under the wing but then I could get the battery back nearer the CoG. I've never done top driven flaps before; there's already a hole for the aileron horn but nothing for the flaps. Looks like that's going to be a jelly moment cutting through that beautiful wing!

My foamie gliders seem cavernous in comparison to trying to fit everything in the Luna fuse, welcome to the world of composites I suppose But I am very, very impressed with this little soarer, just can't wait to fly her! I'll post some photos up over the weekend - old hat to a lot of you I know, but a revelation to this composite convert!

[Rory Gillies]

Well the build is progressing well, motor and tail servo tray installed. There's plenty clearance between the motor bell and the wires, so no need to make a cut under the nose. I opened out the fuse under the wings to fit the servo tray for the tail, far better back there out the way. This will give me lots of options for placing the battery, so once I've wired up the ESC and ubec I'm going to put the wings on and have a play around with battery placement for the best CoG.

She'll be running on 3S, so the idea is to use a 2200mAh or smaller for general use, and a 3500 or bigger for when the wind is howling

Motor mount in place, there's a 2º down and right thrust set

Trial fit of the spinner - might go for a 38mm instead of the 36mm

The opening marked out, just enough to give easy access

After a bit of cutting and filing, looks tidy enough!

Servo tray test fitting - it will actually be a bit further back, with the Rx on its side in front of it

Really enjoying this build so far

[Rory Gillies]

Tonight's job will be to fit the tail control horns and linkages then bind the R617 to my 14SG and have a go at setting up the v tail mix. I'm planning on connecting all the servos directly to the Rx as the wings will remain on the Luna most of the time (it will fit in my car wings on). So the idea is to use Rx ports 1 and 2 for the tail servos, 3 for the motor, 4 and 5 for the ailerons and 6 and 7 for the flaps. This way it will be easy to unplug the wing servos if I have to remove the wing for whatever reason, and easy to plug in again. The Rx will be sitting just in front of the tail servo tray (see photo in last post), so will be easy to access.

Then it's on to the wing. I'm planning on making a basic tray for each wing servo out of 3mm ply which will be epoxied to the skin, then the servo will be wrapped in tape and epoxied to the tray - I figured this would give a secure setup but the servos can be easily changed if need be, without having to remove epoxy from the skin. Does this sound a reasonable way to go about it?

Rory

[Steve Hargreaves - Moderator]

Looking good Rory but just a quick 'elf & safety comment......please remove the prop before powering up for the first time.....electric motors can start when you least expect it...usually due to operator error (knocking the throttle open, reversing the throttle channel...etc etc) & a spinning prop can really make a mess of your fingers/hand/leg.....

So play it safe & take the prop off won't you....

[Rory Gillies]

Good advice Steve. That was just a test fit, the motor wasn't wired up and is now removed until the final stages of assembly, and won't be run with the prop until I do some static tests with the current meter.

It was a fiddly bit of work tonight fitting the tail horns, but they're now installed inside the control surfaces. The control rods are made up at the servo ends, waiting for the slow cure epoxy to set on the horns before cutting to size and fitting the ball ends. Looking good for starting on the wing later in the week.

[RGPuk]

Rory, as a fellow Luna E (t-tail) owner, may I suggest, while you have easy access before the tail servo tray is fixed in place, that you put some glass or carbon cloth reinforcement around the inside of the access aperture corners, as even a slight spin on landing when a wing tip catches heather or a tussock of grass, will produce stress fractures at the corners.

It would have been better to radius the corners of the hole as much as possible - but some reinforcement would still have been a good idea.

You'll love Luna E - I got mine for exactly the same cliff flying as you. The motor will avoid many a drowning when pushing the limits and / or over-optimistically misreading the lift.

Ro.

Edited By RGPuk on 27/11/2013 09:42:41

[Rory Gillies]

Good plan Ro, I did wonder about stress around the opening, so I'll put in some carbon cloth. The servo tray is actually fitted now, but there's plenty room above it to work the cloth and resin.

The tail is now pretty much complete, control rods attached and mechanically centred. I've started programming the model into my 14SG, and at the moment have 9mm up/down on the rudder and 8mm up/down on the elevator. The servo limit is set at 10mm for combined rudder/elevator input as that's about the maximum down throw available on the hinges. In practice I probably won't need anything like these throws, other flyers of this v-tail model are only using 5 or 6mm max.

Dry fit of the tail horns

Tail horns and control rods fitted

The finished tail

Tonight's work will be reinforcing around the servo access (and maybe a bit near the motor mount while I'm at it) then soldering up the electrics and planning the fit. That will see the fuse just about finished so it's on to the wings, my work for this (non flying weather) weekend - not relishing cutting into that beautiful wing to fit the flap controls

[RGPuk]

By way of inspiration - and looking a bit raggy as it was my first mouldie from over three years ago - but if I could do it, anyone can.

The slot in the wing for the pushrod extends about 2/3 under the cowl.

Ro.

[Rory Gillies]

Thanks Ro, any pics like that are a great help and inspiration for a bottom flapper like me! I see the horn is angled slightly towards the LE, is the servo shaft nearer the LE or TE? I've read somewhere that having the control rod as long as possible makes it easier to get good throws at a better angle.

At least there's a vowel to cover the shaft and slot!

Rory

Edited By Rory Gillies on 27/11/2013 18:24:31

[RGPuk]

The horn is angled forward in order to get the pivot point as close to over the hinge-line as possible, to get the best geometry.

Luna is in dock for a service (ahem ... repair ... ) at the moment - so tomorrow I'll whip off an underside flap servo cover and take a snap of the servo install for you.

I'll also dig out the link for the very best flap install guide I've ever come across.

Ro.

[RGPuk]

Pics as promised Rory - plus the link for flap install:

**LINK**

[Rory Gillies]

Ro, thanks for this, it's really helpful. I have slim servos for the wing which I plan to mount on 3mm ply trays, so I should end up with a very similar geometry to yours.

Cheers,

Rory

[RGPuk]

An important detail to try and accommodate is to sort your linkage geometry so the servo arm is in-line with the pushrod at your desired full flap position.

This means that if you whack a flap on landing, the energy isn't transfered to the servo rotationally, which strips gears far more easily. This is easier if you aren't excessively greedy with the amount of up-flap for linked flaps and ailerons for full-span aileron.

Ro.

[RGPuk]

Rory,

You've gone quiet. Hope you haven't epoxied yourself to the workbench.

Ro. ...

[Rory Gillies]

Haha, not quite Ro! All the electrics are done, but based on some reports over on RCGroups the Luna E is prone to stress around the canopy so I've been glassing that up, as well as the fuse under the wing where I cut the servo access.

On the wing I've got as far as setting up the aileron servos and linkages, ready to glue in, then on to the flaps. I probably won't get much time working on her until the Christmas break as I'm having to fly down to Aberdeen twice a week at the moment which is taking up a lot of evenings.

Rory

[Rory Gillies]

Hi All,

Well the Luna is finally finished and maidened in very calm conditions! I didn't complete the build myself as due to the treatment I'm on (I have a rare cancer of the blood called myeloma which has relapsed after five years remission) I find it very difficult to manipulate small objects such as wing control horns. I have no problem with the transmitter sticks however! I packed her all up and sent her off to Tony Fu at Sloperacer. He did a fantastic build on her, complete with Fu-Fix external bearing kits on the wing servos. These make the links really solid with no slop at all, and as they are fixed to both the upper and lower wing skin there's no skin flex, I'm really impressed! He also sanded the nose to the thrust angle so there was no offset gap when the spinner was installed. I had tried 36mm and 38mm Aeronaut Cool Nose spinners and neither of them were an ideal fit. Tony installed a very lightweight RFM carbon spinner which is a perfect fit, and also gives me a few more RPMs from the motor.

The Luna resting after her maiden flight

One of the flap servos showing the external bearing kit

​RFM carbon spinner is a perfect fit, and the nose was sanded to the down thrust angle so no gaps

Under the canopy with the battery in place

When I installed the tail ball links the elevator linkages were causing the pushrods to bend, caused by the ball links being too high for the servo position. Tony set them lower which also helps with the geometry - there was far too much servo movement for the required travel leading to more slop and less torque. Tony reconfigured the ball links and soldered them at a lower position. He also added a former half way down the fuse to guide the pushrods as they were quite bendy in compression. I now have the required control surface travel without any binding.

The reconfigured tail ball links, no binding at all with the recommended control throws!

I had to add 10g lead to the nose to get the CG within range, and by moving the battery back and forward I can get the full CG range of 95 to 102mm.

I'm absolutely delighted with the Luna build. Even though I could have completed her myself had I not had medical issues I now have a very solid e-soarer with a much higher build quality than I could have achieved myself! The next post has a full account of the maiden...

Cheers,

Rory

Edited By Rory Gillies on 05/03/2014 10:49:24

Edited By Rory Gillies on 05/03/2014 10:49:51

[Rory Gillies]

Radio Setup

She's fitted with a Futaba R617FS Rx which is tucked away in front of the tail servo tray. Tony installed a wiring loom with two 4-pin Deans micro connectors which is very neat, and just two connectors to the wings. My original intention was to have the wing servos connected directly into the Rx as I'll rarely remove the wings, but this is a much neater solution. The antennas are taped to the side and across the fuselage under the wing.

The recommended throws are 16mm up/down for the rudder, 10mm up/down for elevator, 16m up / 9mm down for the ailerons, and for crow 35mm down on the flaps, 16mm up on the ailerons and 7mm down on the elevator. I'm using a Futaba 14SG and the Luna is set up with five flight conditions:

1. Normal: the normal flying condition, control throws as listed, -25% expo on aileron and elevator and motor disabled
2. Motor: motor active on J3, 40% differential on ailerons, 50% aileron to rudder mix, -25% expo on aileron and elevator
3. Crow: motor disabled, proportional crow on J3, no expo, 60% aileron to rudder mix, 40% aileron differential
4. Reflex: as normal, 1mm up on flap and aileron
5. Camber: as normal, 3mm down on flaps and ailerons

The Motor and Crow conditions take priority over any other, and conditions are selected using just two three position switches: switch 1 selects Motor - Normal - Crow and switch 2 selects Reflex - Normal - Camber. For normal flying both switches are in the centre position. The trims are separate for each condition allowing fine tuning. The conditions all worked fine in flight, but I've since added 10mm down flaps controlled by the two position switch in the Motor condition only, used during launch.

This is the third full house glider I've set up on the 14SG so I'm pretty familiar with it, but I'd strongly recommend Malcolm Holt's great ebook on this radio which helped me get my head around function based programming and conditions. There's also examples of programming various scenarios including a four wing servo glider, although it uses the motor on a switch and I prefer a joystick.

With the radio programming all complete she was ready to fly! With an AUW of 1640g (57.8oz) she's a bit heavier than the published weight, but the motor pulls 380W on a fully charged LiPo providing a very respectable power to weight ratio of 133W/lb.

The maiden follows in the next post

Cheers,

Rory

[RGPuk]

Rory,

Ah - I guess the regular trips to Aberdeen are explained. I do hope the treatment for your relapse quickly has the desired effect.

It's strange to think that your Luna was down in Leeds and only just up the road for a time - Tony's workshop is relatively local to me. To be fair, it's likely it was there on the bench during one of my visits.

A Mr. Fu fit-out is indeed a class act and it looks like he's really done the business for you. The wing servo bracing and shaft bearings make the handling really crisp.

That shot of Luna by the Loch is lovely - she looks the business - and what a place to fly.

Keep us posted about further flights - and try and get a pal to grab some flying pics that include some of that glorious scenery too.

Keep safe and well.

Rog.

PS. Me and the Missus are contemplating a trip up to the islands - maybe even this summer. The likely toy I'd lug along would probably even be my Luna E.

[Rory Gillies]

Hey Rog, it would be great to see you and the Missus in the summer and get our Luna's up together. I'm going for a stem cell transplant (second one, I had one in February 2009) hopefully mid-May, so should be well into R&R by the middle of June if all goes to plan. I'll be off work for about 4 months and planning on getting a lot of stick time!

Back on topic, the Luna maiden!

The Maiden
The forecast was excellent for Wednesday 19 February so I booked the morning off work. The day dawned as beautiful as forecast, clear skies and no wind, perfect conditions for a glider maiden! I charged two Gens Ace 3S 2200s, packed my kit and loaded the Luna with her wings on into the car.

I chose the Ness of Sound as the flying site, a peninsular just to the south of Lerwick that juts out into Breiwick Bay. This site has slopes facing east, south and west, and the fields are short grass that runs down to the sea. It can be quite muddy in the winter, especially the west facing slope. Although conditions were flat calm the forecast wind was from the east, so I set up in the middle of the east facing field (thankfully free of sheep) complete with GoPro on a tripod and #16 keycam Velcro'd to my hat to catch the action!

The range check was completed without issue, in fact it's the furthest I've walked with this radio and I could still hear the aileron servos operating from the far end of the field - no worries there. After a final preflight she was ready to fly, and there was nothing else to do to put off lobbing my shiny new glider into the sky.

I'm used to launching my Radian Pro and D-2500 gliders at around half power with my right arm, just slightly up from horizontal, so I adopted the same for the Luna. Half power certainly produced a lot of wind from the Hyperion motor compared to my foamies! A good throw had the Luna taking to the sky, although she wasn't ready to climb at the launch power setting. I quickly got may right hand on the aileron/elevator stick, added some more power and off she went with a respectable climb, although she did roll a fair bit to the left as I added the power.

 

Short video of the first launch and landing

I took her up to about 500' and set the normal condition. Once into the glide she required no trim adjustments and I spent some time doing lazy circles. I must say I'm very impressed with the glide ratio, she floated along at a graceful pace in the calm conditions. I tried a stall which comes on very quickly, dropping the left wing and dropping out the sky. Recovery is quick and she was gliding again, just above the stall.

The dive test was almost bang on neutral, I couldn't really discern any change. This is what I expected with the CoG right in the middle of the range and no trim on the elevator. I tried the reflex and camber conditions, both doing what they said and again without any trim changes required. The camber condition allowed me to slow her to a snails pace, I'm amazed she was still flying at such a slow speed.

I was still up around 300' from the first launch, so tested out the crow condition before coming down for a low pass. The proportional crow showed no change in pitch, and with full crow I pointed her 45º down; she descended beautifully at a very slow speed and in full control, excellent stuff!

I brought her down to about 50' for an overhead pass and selected the motor condition. As I powered her up she violently rolled to the left and I ran out of aileron to correct her. At about 5' above the field I killed the power and managed to straighten her up and land her into the mud without damage.

Five minutes spent removing mud from the spinner and tail and she was ready for launch number two. This again caused a violent roll to the left as I applied power and she was into the mud again! Another few minutes of cleaning then the third launch I used a bit more power and a slightly higher launch attitude. This was very messy but once I got her under control and added full power she went up like a rocket, reaching 500' in just a few seconds.

I spent the rest of the flight exploring the flight envelope and trying a few loops and stall turns, then work beckoned and I had to pack up - all good things come to an end!

Final Thoughts
Well I can honestly say I'm delighted with the Luna. She's very different to what I'm used to, but once I master the launch I think she'll quickly become my soaring fix of choice. I think she'll really come into her own in a good breeze on the slope, and the motor and battery will become expensive ballast!

This is my first venture into composite high performance gliders, and it's a journey I've really enjoyed. I've learned a lot about this side of the hobby, and made some new friends on Model Flying and beyond. It's a shame we have such a bad forecast for the next few weeks as I'd love to get her up again, at least I have the Spring and Summer to look forward to, I think the Luna is going to spend a lot of hours in the air!

Cheers,

Rory 

Edited By Rory Gillies on 09/03/2014 10:56:12