After a recent email from Neil at Hyperflight, A big, but very light box turned up on my doorstep yesterday. The majority of the contents in the box were fresh air, but also taped up nicely was one of the first production ELF gliders. The ELF is made by Vladimir's Models, and is a Mini DLG that weighs next to nothing! The ELF is from the same stable as the Blaster 2, and a number of other excellent little gliders! It is a pretty simple model, just a wing, pod/boom/tail feathers and the controls are rudder/elevator only. Estimated all up weight is going to be around 95 grams (3.5oz), and the wingspan is 1m. The wing loading is going to be in the region of 2.7oz/sq.ft, which means it should stay aloft on the slightest of updrafts! It will be available from Neil at Hyperflight imminently.

The parts that turned up in the box were very high quality indeed. The boom is a wrapped carbon affair with a pre-milled slot for the fin, and a flattened section at the front for mounting the RC equipment on. The fin looks like it has a rigid foam core with a vac-bagged glass finish, and live hinged rudder too.. The horizontal stab is similar to fin, although it is designed to mount to a carbon little standoff/pivot providing an all moving stab. Both the fin and the stab have carbon inserts to stiffen it up, and some kind of filler on the leading/trailing edge to provide a degree of ding resistance.

Also included is a rather neat little pod assembly that has been moulded from transparent plastic. It is designed to be bonded to the boom, and has some threaded lugs to locate the wing onto. There is also a nosecone from the same material. The plastic is relatively thick, I was expecting a wafer thin part, but it is nice and sturdy (perfect for my landings!) The wing fit is brilliant, no gaps or fettling needed.

The biggest bit of the kit, and the nicest, is the wing though. It has a large amount of dihedral, but as it is a rudder elevator model, that is to be expected. The construction is a blend of carbon, balsa and film. The spar is made up of carbon, with a vertical grain shear web. This interfaces with balsa ribs that have carbon cap strips, and a moulded carbon D box. The trailing edge is a carbon strip, and aft of the spar is covered with film. The D box and spar are nicely curved, and at the wingtip there is a slot for bonding in the launching blade. The centre of the wing has some reinforcement for mounting it to the pod/fuselage, and a recess to clear a receiver in the pod. The whole affair is amazingly light, and incredibly strong. It also looks rather nice

The accessory pack looks to be quite comprehensive too, some carbon rods for the pushrods, end fittings, screws for the wing, the rudder horn, two launch blades (one for each end of the wing so it can be an ambidextrous model!), the elevator mount/hinge/horn and a few other little bits and pieces too.

I've not had chance to weigh any of the parts yet, so I'll get that done when I get some workshop time on Sunday. Suffice to say it is featherweight though! I'll be fitting a pair of Ripmax SD100 servos for control duties, and a trusty Jeti Duplex R4 . The power source is also a new product that will be available from Hyperflight called the Shread RC Smart Lipo. It consists of a single 240mAh lipo cell, and a small chunk of electronics to provide a regulated 5v output at up to 1A. It also has a warning buzzer to report the cell voltage/low voltage, and a little 2 pin jack. The jack has a jumper fitted to power the device down (remove it to turn on) and the same jack is also used to charge the pack. Interestingly, the charge control is all done by the device, so you just need to connect it to a 5-15VDC power source. The charge rate and cut-off are all controlled by the Smart Lipo, and protection from over-discharge are all integrated too. All this weighs a paltry 11grams, and fits perfectly in the nose cone of the ELF

I'll be taking some pictures of the build, and describing what I am doing, but that won't start until Sunday, but for more information, here are some links:

www.hyperflight.co.uk - UK distributor of Vladimir's models (ELF, Blaster etc) and Shread-RC.
http://f3j.in.ua/index.php?id=190 - ELF product page on Vladimir's website
http://shread-rc.com/?p=6 - Shread-RC product page for the Smart Lipo

Cheers
Andy

I like the ELF it is a lot of fun. Got mine from Barry at Kennedy Composites.

How much from Barry?

It has been a long time ago I think it was $199.00 not to sure.

rcgeorge, is your version the prototype V tail one, or like the one I have with the all moving stabiliser, and seperate fin/rudder? I'd be keen to hear a few more details on it, such as All up weight, flight characteristics etc etc...

Andy

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Before you go off classifying this as a Mosquito class glider, it is NOT a Mosquito class glider.

Mosquito Class was by definiton a glider with a wingspan of 0.75 meters. Since this plane has a span of 1 meter, it is way out of of the class.

There is a big difference in performance increase with the extra 25 cm. If you want to see Mosquito class gliders go to http://spieltek.com/SunbirdSoaring/M...aring-MHLG.htm.



Chris

I've now put up a product page for the Elf:
http://www.hyperflight.co.uk/product...i-dlg&code=ELF

I've also got a few of the amazing SmartLipo regulators:
http://www.hyperflight.co.uk/product...SMART-LIPO-240
Until I get more stock initial SmartLipo 240 units are reserved to Elf purchasers. The other sizes are available for all.

Thanks for the bandwidth.

Neil.

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Thanks Registerwing. BTW I can supply SmartLipos worldwide, and we only charge £2.95 (~ $4.50) postage for small orders. However I cannot supply Elfs to US customers, please get them from KC.

Neil.

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Originally Posted by bigandy

rcgeorge, is your version the prototype V tail one, or like the one I have with the all moving stabiliser, and seperate fin/rudder? I'd be keen to hear a few more details on it, such as All up weight, flight characteristics etc etc...

Andy

Yes mine was the V tail I did not look at yours hard enough. We recommended to do just what you have. The V is a nice flying plane however and it think it was 3.3/4 OZ. It was a lot of fun. It was a plane that we flew to test and then sent back to Barry and so other pilots could try it and enjoy it. It is a great toy.

Originally Posted by registerwing

One thought I had with the li-po is to run a extension lead off the jumper to then also use it as a on/off device while at the field and only remove the canopy [or whatever] when chg is needed.
In that case IM guessing the weight/cap etc along with the alarm is almost half the weight as the commonly used 2 cell li-po/reg/alarm and almost equal features.

Yes, an extension lead would work. Yes there is a big weight saving, obviously dependent upon the capacity of battery 2S you were using.

BTW you don't need to remove the sheath nosecone from the Elf, you cut a small hole for the jumper/switch instead.

Neil.

I've changed the title of the thread to reflect tha the ELF is not quite a Mosquito class DLG. You learn something new every day, so thanks for pointing that out Chris.

Anyway, on with the build. I didn't get as much time as I had hoped on Sunday to start assembling, but I managed an hour or so. The accessory bag has pretty much everything needed in it, the Stabiliser V mount, 3 little tube/wire pushrod ends, an L shape pushrod end for the V-mount, a little carbon rudder horn, wing retaining screws, two carbon launch blades and a pair of screws I don't know what to do with at the moment

The first job, is to fit the V-mount to the horizontal stabiliser. All I did was cut a 16mm line just aft of the carbon spar in the stab (centred of course!) with a scalpel. I only went through the lower glass surface. I then smeared the contact faces of the V mount (it has a little blade that is inserted into the slot) with some thick CA, Zap's finest btw, before inserting it into the slot. A bit of pressure to ensure it is seated correctly, and all is done. You do have to be careful not to get any CA in the hinge, I found using a cocktail stick to apply the CA worked great.





Next up is to cut a slot in the rudder to accept the little carbon horn. This is marked out as per the instructions (50mm from lower edge) and again one glass surface is cut with a scalpel. Thick CA was used on this part again, but I did give the horn a light sand to remove and release agents that my affect the bond. I was also careful to ensure the horn was butted up against the inside of the opposite skin, to ensure a nice rigid joint. At this point, I am going to deviate fro the instructions a bit. The rudder is designed to be actuated by a carbon pushrod. I'm a big fan of spring/pull linkages, so that's what I am going to do instead. I made a spring up by bending two 90° bends in a 50mm length of 0.4mm diameter spring steel wire. Bending them into a "C" shape, allows one prong to be inserted in the rudder, and one in the fin. The rudder will then automatically be pulled one way by the spring, and the idea is that a pull cord actuates it the other way. The picturs explain this better than words. I used some CA to bond the spring in place. The foam core is not the strongest material when a spring is acting on it, so I wicked a TINY bit of thin CA around the spring prongs to bridge the glass skins, and ensure it can take the loads without falling apart.











With the fin complete, it's time to bond that in place. I almost forgot to slide the pod on, which would have been a nightmare to remedy, but luckily I stopped to double check everything before applying glue! Lining everything up is dead easy, and I used more thick CA to bond the fin to the slot in the boom. When this has cured properly, I'll put a few wraps of kevlar around the boom at the LE of the fin. This is always a weak point on DLG's, and the weight is well worth the increase in strength/toughness.



More inna bit
Andy

More build time yesterday evening. A bit of careful alignment and checking saw the horizontal stab in position, and a wee bit of thin CA (Zap's pink finest) wicked into the V mount where it contacts the boom, saw it locked in place. There does seem to be a bit of flex in this mount, primarily in the plastic v mount (the carbon blaster one was rock solid). This may prove useful in the event of a botched landing. Hopefully Vladimir has got the amount just right though, and it doesn't cause any issues on the launch.



With the back end all bonded in place, it was time to move onto the pod. This was aligned with the wing in place to make sure everything was square. Once it was, Zap's finest pink CA came out again (the thin stuff) and it was wicked into the join between the pod and boom. With it tacked in place, the wing was removed, and more CA used to make sure the bond is good. Incidentally, I did roughen the contact surfaces with a bit of sandpaper, to remove mould release/and provide a bit of a key for the bond. I'm not 100% sure of using CA on flexible plastic, because it can crack (the adhesive), but I'll see how it goes.



More in a mo...


Andy