Peter Jenkins

Well, we are in official Spring and today did feel very Spring-like

Nice morning for a maiden flight. Bought a second hand contra drive and second hand airframe. Needed a new ESC and props - expensive. Got in 4 flights and lots of progress on trimming. Probably needs another 10 flights or so yo get it completely dialed in.

I have given up using Wattmeters and use on-board telemetry. The system I use is called a Unisens-E and is made by SM Modelbau (link). This unit can be set to speak Futaba, JR, Spektrum, Powerbox and a lot more. You get both real time indication of current, voltage, power, as well as a max and min in the flight provided you don't turn off the Rx before checking the max/min figures. You also get a height read out and a vario if you are into thermalling. I found on a static ground run, full throttle gave a reading of 3,600 watts and 99 A! I shut that down PDQ. In the air, the full throttle reading was usually around 2,70 W and 80A. Only once, did I see a max of 2850 W. So, if you set up your system on the ground and, quite naturally, don't want to exceed the maximum power/current for your motor/ESC, you will always be underusing your motor's power. In the case above, the difference between static and dynamic tests is 28.6%. Now, I only ever check for max power in the air. I recently ran a test on a contra drive using a 10S pack and this was the outcome of the values I was prepared to inflict on the drive. The motor has a max power of 2,800 watts and 80 A. These figures were with the throttle stick at around 65% open. I fully expect that the full power in flight figures will not be too far off these ones. The screen shows the max values during that particular operation. So, the Watts show 2,709.8 for an rpm of 3,789 and Amps of 71.9 A. Ignore the voltage figure as that is showing the maximum voltage that the system saw and that would be at the initial plugging in of the flight pack. The min values would have the voltage that corresponded to these power figures. The props, by the way, are a pair of 22 x 20 Falcons. The Unisens-E is a very small device and you don't need any other sensors other than what comes inside the less than 20 g unit that costs Euro 65.90 + shipping. No doubt it can also fall foul of customs but it shouldn't at that price. It is easy to swap from model to model provided you have leads to the Rx that you can plug into as well as a lead from one of the motor 3 phase wires to give you the rpm signal. I just use servo plugs to make swapping the Unisens-E between models very easy. SM Modelbau also sell a device called the Unilog 2 that has a micro SD card that records every flight and can be read off line but that costs Euro 99 plus you need to buy the SD card.

And close to a MATZ and the London TMA. Narrows it down a bit more.

I do hope this wasn't a BMFA Club or originated by a BMFA member. I hope that Manny or Dave will take this further and if it turns out to be a BMFA Club/member, then put them in the right as regards the rules of the air. One has to wonder who this person is that they think a NOTAM about an activity means that absolves them of the usual rules of the air!

Are you able to reduce the control throw by moving the pushrod to a more inner hole on the servo or more outer hole on the control horn?

Can't have been much fun for those who didn't have his marksmanship! 🤣

Two cracking games today where the underdogs came out on top. I just hope both England and Italy continue to play in that way. George Ford seemed to be having an off day on the kicking front but loss of 8 points (1 conversion and 2 penalties) rather made the game the exciting spectacle it turned into. Marcus Smith played a blinder with that very last kick in the red time zone. But well done to all 4 teams for the most exciting 6 Nations day. What will Wales-France bring tomorrow?

Do you use Rates?

Dare I ask which make of servo? Alternatively, were they main stream brands (Futaba, JR, Savox, Align etc) or lesser brands?

That would make up a schwarm or two rotte.

Hi Richard I'll take it. Don't know why as the Spitfire is still in its box! Peter

Hi Jim Firstly well done on getting your first YS. They are highly specialised engines used primarily in competition aerobatics before the advent of electric power. They are more powerful than you would expect for that size of engine as they are supercharged and fuel injected. They require some special handling but I'm assuming that you have read up about it and have the necessary understanding of this device. They also need an anti vibration mount and they can be hard to come by. The Hyde mount (made by Chip Hyde) is still the go to mount for a YS. £360 for an ARTF that has a 10 lb weight is quite reasonable IMHO. I would just point out that the YS was aimed at aircraft that weighed 11 lb. If you were to buy the sort of aircraft that the YS used to go into (a 2 mtr pattern aircraft or F3A) you'd be talking about paying £2,000 +. The Ultimate will be a bit overpowered with the YS and it is a good deal heavier than a 20 cc petrol engine. You are no doubt aware that the YS needs high nitro fuel, ideally 30% but that's now all but impossible to get. 20% seems to be the limit for legal reasons. Enjoy and do let us know how you get on.

Must be the first time a seagull photo bombed the Red Arrows eh? Beaten by Eric!

I did charge a guy who was learning how to fly but as he didn't have a suitable trainer I charged him £1 for every flight with my trainer aircraft which I thought was fair as I'd paid over £300 to get it up and running. He was quite happy with that especially since it was all properly setup and we didn't waste ages getting the motor started etc! Choke, back flick or two and engine running.

Did you check how much charge went into it? If that was what you expected that is a bit worrying. I've ddcided to use Eneloops for NiMHs but I also use 2 cell LiFes and LiPos. So far, touch woid, not suffered your problem. I didn't like yo use NiMHs that had not been used for a year or else do a cycle to check capacity.

What type of battery?

England were too inaccurate to capitalise on the many strong positions they held. Congratulations to Scotland on an emphatic win. Finn Russell and Duhan van de Merwe were the outstanding contributors to the score sheet.

Well, all to play for in the 2nd half. Who wants it most and will England cut out the handling errors? Van de Merwe's 2nd try was pure pace!

I think the outcome of the next match rests with how England perform. We know the Scots will be on the top of their form against the auld enemy!

I'll start the ball rolling today! Can't see Wales winning against Ireland so I think that should be a done deal. England/Scotland on the other hand is very difficult to call. Scotland always seem to play out of their skins when facing England and England seem to be tentative when they've played Scotland in the last few years as they've tended to lose. My feeling is that England will win this by a very narrow points margin but it could easily go either way.

The alternative is to retrim twitchy models so they aren't twitchy - quite often reducing the control throws is sufficient but you may also have a rearward CG. I was scared stupid when I offered to recover a chaps Angel 30 when it got too far away for him to see what was going on. I found it almost impossible to fly till I acclimatised to the huge control throws he had. After landing the Angel, beautifully I might add(!), I took him to see how much movement I had on my aircraft. We turned down his control throws to the same as my set up and his flying was immediately improved and the aircraft no longer scary to fly. The other thing is to learn how to land in a gusty cross wind but always be prepared to overshoot if things get out of hand. You can always use the gyro as a back up to dealing with the cross wind yourself.

Plus you have to be "caught" in the act!

I suspect that under the UK spec, assuming it has a CE label, its range will be limited because we are not allowed to have more than 10 mW transmitter output power. I think in the USA you can have 100 mW of power but that is illegal in the UK.

Continuity is the best way of learning anything.