Basic aeros - testing the flight envelope

Stu and Jas prepping for the flight

Under Stu's guidance I thought I'd run through a few 'basic aeros' today, both to increase my flying skills and test the flight envelope of the Skywalker X5. I have no carbon fibre spars reinforceing my wings so I was interested to see just what they could take.

I wasn't sure how we were going to go as I have very minimal throws on my controls (20%) and I haven't setup dual rates.

Doing a loop was no problems at all, she handled that just fine. However I tried doing a roll and that didn't work, all I got from that was a wingover and a steep bank towards the ground! I might try again next week and this time I'll program in dual rates and test the high rates out.

So I called it quits and decided a few loops would be good enough for me, a successful morning of flying is a tick in the box for me.

Setting up for a loop with the Skywalker X5

Read More

Round and round we go

A stiff hand throw and the Skywalker X5 takes flight 

Hand launching the Skywalker X5 has proved to be the toughest part of testing so far. Getting a reliable launch is a real challenge, she doesn't handle crosswind well and needs a dang hard throw to get her moving.

So today I thought  I'd take the X5 up for a series of circuits, to get as many hand launches in as possible. The drill was launch, do a couple of circuits, land and then repeat. This not only gave me plenty of practice at what is required for a successful hand launch, it also gave me an opportunity to hone my landing skills.

The real gem that I discovered was that after about 20min of running time the batteries started to run lower and hand launching became very dangerous because the takeoff thrust was noticeably less. Not that this is likely to happen in a 'real world' situation, but it's an excellent piece of flight performance data to know.

It wasn't the best landing of the day!

Read More

Beefing up the motor mount

The beefed up motor mount just prior to installation

I've had one too many 'poor launches' which have sent the Skywalker X5 cartwheeling across the field, this has resulted in the top screws being ripped out of the motor mount!

The broken Skywalker X5 motor mount

I guess it was inevitable, whilst the bulkhead for the motor mount glues well to the airframe, the bulkhead it's self is only a thin piece of ply. I expect only one or two screw threads to be gripping the ply and the rest are just sitting in the foam.

Anyway, I decided to 'beef' it all up with a set of longer screws, wall plugs and metal washers and have glue four wall plugs into the foam and have used longer screws.

Hopefully the combination of the new beefed up motor mount and successful launches in future will mean that I have no more problems.



The components used to reinforce for the Skywalker X5 motor mount 

Wall plugs, longer screws and metal washers, all part of the new motor mount

Read More

Stall and spin testing

Pulling the Skywalker X5 up into a stall to create a spin!

Today I had scheduled to do some more flight testing, I needed to see how the Skywalker X5 would behave in a stall and spin. This would be my first time ever testing a model aircraft in a spin!

Overall I was pretty happy with the testing for a couple of different reasons.

Initially I took the X5 up quite high and then started throttling back and giving her up elevator until she stalled. Most of the stalls were quite mild and I could hardly notice much more than a slight nose drop, I was happy with the results.

Next I tried a stall at a lower altitude as well as on a downwind leg, this is where things turned a little pear shape! Yep she stalled alright and she spun, quite hard, what made things worse was that it caught me by surprise, I panicked and instinctively pulled up on the elevators hoping to pull her out of the spiral dive ..... you can guess what happened next can't you, yep she spiralled all the way to the ground head first, POP!

When I went to investigate the damage I was pleasantly surprised, a very slight crinkle in the nose but that was it. I did a five minute check over everything and decided it was all ok and hand launched it back into wind, no worries she took off like a dream. The X5 is one tough mudder!

So, I had received my wake up call and luckily had been given and second chance. Undeterred I took the X5 but up to altitude and induced a series of full spins and recoveries, this time keeping my cool and using the correct spin recovery technique. I have the X5 with a forward CoG so the technique for me was simply let go of the controls, within one full spin rotation the X5 had built up enough airspeed and had broken herself out of the spin, all I had to do was pull up.
 and the recovery was complete.

I continued with the spin recovery practice for a good ten minutes, entering the stall and then a spin  and then recovering. Sometimes I even held the spin for a good three, four maybe five rotations (just to see how she would handle it) before starting the recovery procedure. I declared it a successful testing session and bought her in. I haven't built up the courage to try a low level spin again yet but I will try one again soon.

Next on my list for the flight testing is basic aerobatics, you never know I may need to call on my newly found spin recovery skills then.

Read More

Visibility markings

I added some cloth tape to both sides of the wings in order to give the Skywalker X5 some better visibility when she's in the air. Often with the glare from the sun I would momentarily loose ..... which can be un-nerving. I think I have solved this with some clear markings.

Read More

Fixing the hatch lock down

Everything you'll need to complete this task

The hatch lock down screws have slowly been getting harder and harder to tighten. I'm not sure whether I failed to align them correctly when building the Skywalker X5 or not. Anyway it seems that the screw is made of a harder steel than the bolt/nut and what is happening is the bolt/nut is slowly getting crossed threaded. I think I'd prefer that is was the other way around, the screw broke before the nut as the nut is the one that is cast/glued into the airframe!

The old system with bolt/nut glued under the plywood bulkhead

So I cut the plywood bulkheads off the base of the hatch and took the stock bolt/nut out. I then got a couple of M3 screws and nuts from the hardware store, re-aligned and glued them into place.

I used longer screws and put a nut at the right length along the screw as to tighten the hatch properly. Hopefully this will also help with me not loosing the screws in the field as this time they are longer and therefore easier to find in the grass.

The new system with longer screw, locking nut and double bolt glued to the plywood bulkhead

Read More

Takeoff and Landing Tests

Skywalker X5 initial flight testing

Cousin Tye dropped in today on his way from Alice Springs to Bunbury ..... so it was a good excuse to go for a fly.

Wind was a westerly at a gentle 10km/h today. Today we trimmed the Skywalker X5 up a little more and practiced hand launching as well as landings.

First off the X5 seemed a little tough to trim but we persisted for a few minutes and in the end she flew straight and stable. I'm still getting used to her speed. Landings were straight forward although I can probably come in with less airspeed.

Overall I was very happy with the flight testing, I'm getting more confident with the X5's handling and my abilities. Next time will focus on hand launches and landings again but see if we can test stalls and spins as well.

Successful hand launch

Launch, circuit, go-round and landing

Last landing of the day

Read More

Launching challenges

Catapult bungee setup for launch

Launching wings has been a bit hit and miss for me, until I got my confidence I would often get a wing over and cartwheel them into the ground. Because of these past experiences I was quite nervous about following up on Stu's successful first launch of the Skywalker X5. Developing a system for launching it reliably by myself I knew was going to be a challenge and may possibly involve a few crashes.

I had a bungee catapult in the cupboard so thought it could be a way of getting airborne with the least amount of heartache. The thing with bungee catapults is that they help to give a more consistent launch, something that hand launching is not known for.

So Harry and I built it in the morning (didn't take long) and tested it on the back lawn. I loaded the bungee about half way, connected the X5 to it and got Harry to trigger the foot pedal on my command. The very first time we did it Harry got a little overzealous and stomped on the foot pedal as soon as I asked him to come over and get ready, lucky for me the bungee barely had enough in it to get the X5 off the frame and it flopped onto the grass unharmed. the couple of tests were a little more controlled and we got it to launch a metre or so into my open arms (very serious wicket keeper pose).

With initial tests complete we headed to the Woodbridge flying field for the real deal. It was 32 degrees, the wind was E/SE 19km/h gusting to 27km/h so we had a nice breeze to head into.
The bungee catapult launches were not that successful, all of them resulted in wing overs and one with the X5 doing three cartwheels over the grass, the only saving grace was that I had the wisdom to make them all no-power launches so the inertia was low.

Fed up the bungee catapult I decided to give the old hand launch a crack. Again I decided a few power off glide tests would be prudent before trying a full power launch. The first attempt resulted in a mild right hand wing over but I just managed to recover. I trimmed the aileron and tried again, success! Three more just to make sure I had the right system and all was looking good. I then went the 3/4 power hand launch and she went off like a dream.

She climbed quite quickly and I noticed that the up elevator I had set last week was too much as I could barely make her fly level. I gave her full down trim and the Skywalker X5 felt much better. I flew a couple more circuits, flying across in front of me where I could see how she was responding. Trimmed her up a little more and other than being bounced around a bit by the wind was happy with the end result. I'll now make the current trims permanent mechanical trims and put the Tx trims back to neutral.

It was an excellent flying session and I'm very pleased with what I have learnt. I was really hoping I would be able to reliably launch the X5 without a bungee catapult, for such a small airframe I thought it was going to be a shame to have to lug all the extra gear around. So I'm happy that the catapult didn't work for me but the hand held launching did. The catapult can go back in the cupboard and may come out when I get a much larger airframe to launch.

The next step is to continue to work on perfecting the hand held launch, confirm that the latest settings give a stable flight and practice landings. Hopefully I can get back to the field this week for a good 30min flight of simply taking off, flying a circuit or two then landing and repeating that process over and over again.

Read More