Monday, 23 September 2013

Videos of the 'Brit Schwingey' maiden test flights

Brit-E-Schwing from Jonathan Wells on Vimeo.

Brit-E-Schwing-TFu from Jonathan Wells on Vimeo.

The ‘Brit Schwingey’ has flown and it was better than we had hoped for! Here are some videos, they don't really do the speed justice, look at what happens when diving straight down from height- well it certainly felt faster (and scarier) than that! 
We had a 6hr outing and I can’t say I’ve had a better or more memorable flying session, never mind this being it's maiden test flies! We flew off a slope in light Westerlies probably no more than 10mph and very little thermal activity and conditions so poor for sloping that a big 4m Ash we shared part of the day with struggled to get away and only managed to get high enough before the worried owner cut his losses and came in to land. 
We, on the other hand, we’re having a ball- the best way I can describe it is as though we were on a fantastic hill and best thermal passing through but continuously! 
It wasn’t like that on the first few flights which was trimming and altering the cg and crow brake settings.Here we were just testing the motor on climbs and dives until we had the plane trimmed- now that was fun with big dives down with a few antics on the way down and a few loops and rolls until the speed bled off.
On the glide for the conditions it felt like a heavily loaded plane at 2.4kg which it is but as the speed got up it felt rock solid. Then I started to merge the power with the glide not to gain height necessarily but to kick the plane with more and more speed especially at the ends of each pass across the slope. The fun really started! Once it got going it just needed a blip of power to get faster and faster. We did the big loops right in front of us powering on the bottom and climbing up then off as it went round and it just speeded up with each revolution. It just felt like DS’ing! Flying the power like this just made a poor slope with poor lift far more entertaining. The props folded pretty much immediately so it could be dived as soon as the power was off which was then seamless flying between power and glide. The videos just look like a Schwing on a good day, on a good hill, only it wasn't and you certainly couldn't throw around a heavily loaded glider in the way we were on just slope lift. I guess having this capability is the whole point of flying electric for ,me.   
Jonathan Wells, our local wonder kid turned up late afternoon and put the Brit Schwingey through it’s paces. It wasn’t all perfect, the power on did produce a climb with the plane wanting to do a massive loop but it wasn’t too bad and it wasn’t crazy amounts of power but looking at my tranny timer we were getting around 2 mins power on with each battery before you could tell the motor beginning to flag, which is much better than expected. Back in the workshop looking at the Castle Creations logging it was clear we were getting between 1500 to 1200w in the air and about 60a current draw average. This was confirmed with the charge back into one of the packs which was around 2000mah so dangerously close to fully depleting the 2250mah pack! Each power on was only short the longest being about 3s and usually just a second or so. If you recall the static test showed 1971w with a pack straight off the charger. I guess the lower power rates compared to static is that the way it was flown fast meant that the prop had less load on the motor.   
Even so when checking the packs and motor on landing they were barely warm. a sure sign that nothing was stressed. Certainly the power system is under propped but it was just effortless speed at will and the last few sessions was just prolonged aerobatics and F3F style racing at break neck speed! I'll leave it for others to tune the power set up to get the maximum power. We'll try a 3s set up next with a second prototype around 950w static, still a decent amount of power but lighter (I reckon under 2 kg) and less frightening for us slope boys, not used to high power E planes! 

Tuesday, 17 September 2013

Brit. Schwing-E

The 6s (2Kw) version of the prototype Schwing E has been ready for it's maiden test flight for a few days now but the weather is holding up play!

The 'Brit Schwingey'  is waiting menancingly and patiently.

In the meantime, here's the latest info about this particular prototype.

The build for 6s has been a bit of a head scratching excercise but it all fits beautifully and comes in at just over 2.4kg so like the standard glider with 6 or 7 slugs of ballast. Incidentally, a 3s version will come in at well under 2kg and 4s just over.

Power set up is with a Reisenauer Micro Edition Plus 5:1 with a Leopard 2860/2040Kv using a Castle Creations 100a Edge Lite. Tests with a RFM 16x16 wide gives 1971w, static, with 6s Thunder Power 70c 2250mah. (power to the RX and servos is via 2s 1200mah lipos). For the first few flights at least this should be more power than ample but there is room to 'prop' harder and get even more power from this set up!

 Anyway we'll know soon enough...
Affectionately dubbed the 'Brit Schwingey'

Some fancy wiring circuits to allow switch and RX charge plug in the removable nose cone but the practicality and convenience was worth the effort

Well it needed some stripes! 

Cooling exit holes and just make out the external antenae position.- It's carbon reinforced from nose cone back.

On this nose heavy 6s version both elevator and rudder servos are in the fin. We used KST DS113MG and external bearing kits. This servo is 11.7mm thick.

Here's details of the motor installation with a carbon ring supporting the back end of the motor

The gearbox mounting just fits using the upgraded gearbox in this 6s version, normal motors will not be so close!

Here's the bottom of the fuse. The larger M4 bolt is to retain the nose cone and works really effectively. The smaller M3 bolt is to retain the RX lipo which is held on a flat plate going down the boom. The length adjusted the Cg to within range allowing fine tuning with main flight lipos location. The glass cover is a cooling exit with the scoop going into the fuse. It covers an opening making RX access much easier. Then lastly, there's the external aerials held 'out there' with a thin piece of G10.    

Just plug in the lipos and push on the nose, all the RX connections are made automatically, the flat sides and shape in general helps with positive alignment. Then one bolt to do up and it's good! 
Here's the female MPX located in the rear fuse which auto mates with the corresponding male attached to the nose cone. It's very securely bonded in! All 6 pins are used for the ESC, RX lipo (switched) and 2s balanced charge. Took some figuring!  Of course 3s and 4s versions will probable use the ESC BEC and no need for this type of circuit but the MPX 'greenies' are great for auto mating like this.

Well love or hate the scheme (we love it of course) the design of the E fuse is an exercise in function over form! This has all the credentials for a really great hotliner.

Tuesday, 3 September 2013

The E Schwing is born!

Just beautiful,retaining much the same lines as the glider version  
It's finally a reality! We have 2 prototype E Schwings to build up and test fly and to say I'm excited is a huge understatement. The design is capable of being an outright hotliner with the option for anything between 3s and 6s and I'll be building both versions at around 900w and 2kw+. Of course this is just to demonstrate a hot set up for these size batteries and I've no doubt the Schwing will tootle around on much less. However, we've done a lot of motor testing already and the best power/efficiency/weight is with a 4s set up.
Right from the start it was designed as high power electric so it has a removable nose cone- much stronger than a canopy with a big opening! The functional shape is flattened and widened just enough to take the power system.

The nose cone has a cooling air intake moulded in on the top. The battery extension forms a strong platform to carry the lipos. The lay up is glass and has come out very strong.

It was sized for Thunder Power 3s 70c 2250mah which is the biggest that will fit in this format.

A 6s set up is just 2 x 3s packs joined in series. (Of course this also means 4s systems will have no problems as a 2s +2s). Here's a very special 6s version of the Sloperacr Motor using a lower wind (2040Kv) and upgraded gearbox, Reisenauer Micro Edition Plus. I'm expecting well over 2Kw!   

And here is the baby set up using a 5:1 geared outrunner (4300Kv). Tests with an Aeronaut 14x12 gave 950w static (using TP 2250, 3s, 70c and CC Edge Lite 100a)! It's very light as the motor and g/b weighes just over 100g! Basically, anything 28mm diameter will fit but nothing much bigger. The front hole is sized 32mm diameter.  

The bottom of the battery extension has a mould chine for strength but also forms a nice channel for the ESC wiring to the RX.   

Views of engorged rear fuse. The lay up is glass kevlar and carbon reinforcement behind the battery area and all the way up the fin. The area just behind the rear incidence pin is big enough for Rx and rudder servo and elevator (if not putting in fin).
Here is the air exit slot 

The nose is long enough for decent size props. Here is a long skinny RFM 16x16 and a 32mm spinner

It's still very sleek and skinny and retains the sleek lines of the glider version- just a bit more to grab now which is no bad thing launching!  

So much power in such a small space, well at least it's been designed for the capability!  

Same wing and tail spacing making the glider and E fuse interchangeable

Just got to build up and fly them!