Wednesday 29 August 2012

Some settings for my F3F Skorpion and how I arrived at them.


 
On the weekend I finally tackled trying to improve the handling of my Skorpion and have had a couple of requests to share my settings and how I arrived at them, so here I go.

Firstly I should clarify that I am by no means an expert and any information I pass on has been gained from others at race meetings and from articles such as Kevin Newton’s brilliant ‘how to set up a racing glider’ article from his website (http://kevin-newton.blogspot.co.uk/2001/01/how-to-set-up-racing-glider.html) and Andy Ellison’s article (On The Edge Special 2010 – Setting Up A Slope Racing Glider) in RCM&E. Another clarification from my point of view is that my plane’s CofG is at 110mm from the leading edge at the root of the wing on my Skorpion F3F and I understand that most people don’t fly quite that far back so any measurements or settings need to have the twitchiness of my CofG kept in mind.

One thing Kevin’s article definitely taught me was that experimentation and tinkering are key. Although I haven’t been disciplined enough to record the results of any Tinkering and would suggest doing so to others as it saves all sorts of hassle.

Right then. On Sunday I decided to correct the handling issues I had been ‘flying around’ on the Skorp. I wasn’t comfortable with how the plane was entering or exiting the turns on simulated F3F runs especially using the reversal turn (my preferred turn style). I felt as though I was constantly correcting the plane and fighting it to stay on the course and I noticed that the nose was slightly high through the turns, along with shifting towards the slope with the application of rolling away ailerons. On the ground I checked the current state of aileron differential and they looked to be moving almost an equal amount up and down. This setting was giving me the poor flights. Using the aileron differential mixer on my transmitter I adjusted the differential to have almost zero downward travelling aileron (I was working on the theory that I will see the change markedly if it is a BIG change!). I had to remind myself before the test flight that I would have much reduced aileron authority, especially when landing and turned the aileron-flap coupling and snap flap off for landing (looking forward to getting a Transmitter that can set a landing phase with those mixes OFF at the flick of the Landing switch). Test flight time and the change was pretty extreme! The plane was now pulling away from the slope when ailerons were applied and the nose was very low in the turn. But it was WAY too much of a change as the plane was now barreling back towards me out of the turns and trying to fly behind me! Although it was only a short flight, it told me that I had changed the plane in the right direction. I had just made the adjustment too large. After remembering to flick the three switches and successfully landing I adjusted the differential slightly back towards the starting point giving approximately 8mm down aileron, 20mm up aileron and 4mm up and down flap. These eyeballed (not measured) settings gave me the results I was after on my next test flight (very much a fluke to get it in 3 flights!!) and suit my CofG and my flying style. My plane now exited the turn along the slope at a trajectory that I didn’t have to fight and it’s line was such that I hardly had to adjust it before entering the next turn.

Next up was Snap-flap (SF). The amount of flap/aileron linked to the movement of the elevator (ele-flap mix on my transmitter). Again I subscribed to the more is more school of thought and for the first test flight I tested the difference between my current settings and none by switching it off during some test runs. I hardly ever pull full elevator and don't feel like the plane is close to flicking so didn’t see the benefit in doing the three loop test. I prefer to test for energy efficiency using the reversal turn as per my racing. After practicing with your own plane and learning what is pinging back out of the turn or not, you will know what is best for your plane and flying style.

The first test flight taught me that the amount of SF I was using at the time was an improvement on not using SF as the plane slowed down less when the elevator was used to complete the reversal turn when SF was used. The plane did not maintain it’s energy as well as I had experienced before, so I knew changes needed to happen.

For the second test flight I reduced the amount of SF by half. This change was wrong. The plane lost more energy in the turn. The third test flight increased the SF from my starting point giving me a maximum of around 6mm SF with the full 5mm up elevator travel.  Again I will reiterate two points. A) I hardly ever pull full elevator and B) my CofG is at 110mm. These eyeballed (not measured) settings gave me a much more energy efficient glider which completed it’s turns giving what seemed like acceleration out of the turn.

With my broken F3B Skorpion, I experimented with having the SF on a curve to deliver the SF biased to the start or end of the stick elevator travel. I found that early SF worked better for me than late although Linear SF works best for me. I think I would like to try late SF again though for using the EM turn style.

It is very possible that I will get to the slopes next time out and the conditions will be different and my settings will be wrong. It is also possible that I will want to fly a different turn style on a different slope and the settings I have will make that style hard work.

The best piece of advice I ever received regarding settings is to ‘just play around with them and learn what works for you’.

I hope this encourages some of you to have a play and learn what works best for you and your planes.  

Sunday 26 August 2012

Bwlch session today.

The weather played nice today and we managed to get a great flying session in on both the Westerly and normal faces of Mickey's slopes.
 
Arrived at 1030 after a nice relaxing drive and met Rog in the parking area. Loaded my gear onto my back and started the long trudge walk to Mickey's West. "Wotcha flyin today?" asked Rog, "the Skorp and Wasa...... just the Skorpion, the Wasabi is still on the bench" was my sheepish reply.

We were greeted at the slope by three keen flyers making the most of the smooth, substantial lift in the form of local boyo Mark and two Whitesheeters Graeme and Tony. Quite an impressive assortment of planes between them.
A crew from London parked themselves along the slope a little and kept to themselves for the day, although I did have a quick chat at the carpark later.
Andy arrived, said hello and then Roger and Mark were feeling a little bit clostrophobic so they upped sticks and moved to a different part of the Bwlch to steer clear of the rest of us. I don't think And's personal hygeine had anything to do with the exodus, but my nose isn't as sensitive as it used to be, so you never know.

I started to rig the Skorpion and then realised that I had left my transmitter at home, sitting next to the Wasabi on the bench!! What a div!!
I walked back to the car, drove home, grabbed the Tx and Wasabi, drove back and walked back to the slope. That took about 1.5 hours, which I would have preferred to have spent flying and chatting.

I finally got to have a few flights of the Skorpion and Wasabi. Landing on the Westerly Slope of Mickeys is soooo nice, I love the amount of room and smooth wind. Even landing the Wasabi was simple as it was possible to fly a figure of 8 until the airspeed was low enough to land safely.

While flying the Skorpion, I kept analysing it's flight, thinking that I should play with the differential and snap-flap as it doesn't quite seem right. I didn't do anything about it and kept putting it off. I am the king of procrastinators.

We ended up shifting to Mickey's at about 2pm as the wind had shifted sufficiently to the south west to make the flying uncomfortable and the rewards for moving were substantial (if you like compressed air!).

Our numbers slowly dwindled until just Andy and I were left flying and I finally decided to tackle the Snap-flap and Aileron Differential. It only took me an hour and about 4 or 5 flights, but I am MUCH happier with the way the Skorpion is flying and am now relishing the thought of competing at the Welsh open.

Andy took a quick clip of one of my flights this afternoon.
I carried my camera, a tripod and my video and didn't use them at all.

Here is the clip Andy took.




I am well worn out tonight but very pleased to have had a full day of flying with my mates.

Bring on the next session!

Font d'Urle video by Planet Soaring

Pierre Rondel uploaded this fantastic video from a recent F3F comp in France. Fantastic.


Font d'Urle 2012 from Pierre Rondel on Vimeo.

Saturday 11 August 2012

Kinetic on the Crest

Popped up to the Crest of the Bwlch today to catch some sun and hopefully have a couple of flights with the Wasabi and Skorpion.

Keith arrived just before me and we got chatting about his Kinetic while we trudged out to the Crest.
Keith has been working on his Kinetic aerobatic glider project for a while now and by the sounds of things this 2 and a bit span hollow moulded aerobatic glider is not too far away from realising Keith's dream of producing the Kinetic for public consumption.

It fly's very impressively and managed to scratch around in minimal lift looking for the thermals pretty well too.

I took some video and pics that I would like to share with you. I don't have Keith's contact details, so if any of you know him, point him here for a squizz.









Thursday 9 August 2012

Andy Evans first F3F run

My mate Andy had his first F3F run on Sunday at Slopeglide and I managed to catch it on film.

I thought he did very well and successfully recovered from a cut too (even if it was towards the slope!). Congratulations Butt!

Monday 6 August 2012

Slopeglide 2012

Finally I have managed to compete in an F3F event! I have added my version of a race-report on the race reports page here

Thanks Clare.