 BMFA club affiliation No 0340
May 08
FLY SAFE - Fly Again
Next gathering at St Andrews Rugby Club, May 5 2008 then June 2nd
Mike is keen to get £30 off members, which must be paid before end June. I know what you lot are like - you will forget, do it NOW, thanks
Don't forget Lads, check the website frequently for any breaking news and info, and please pass on info to make sure everyone knows.
Our Webmaster is always on the lookout for pictures and useful info to make the site appealing and worth browsers visiting. It is one of the clubs recruiting grounds and our face to the world.
Another web site that needs support to make it a useful recourse is http://www.bmfamid.co.uk All with e-mail should have received this link from Mike recently. I have had a look and with support from BMFA members in the region it should prove to be a good discussion and information point.
Now a warm welcome to some new members. Robert Seymour, an old hand but somewhat rusty in model flying. But he does know about big planes, he is a semi retired airline pilot. Lee Russell, Kevin and Ashley (son) Woodward are all novices, and will be glad to have help advice and mentoring. Rally round lads to give them a good start and encouragement. You new lads will soon discover that the newsletter arrives approximately bi-monthly - sometimes more frequently if you are lucky!
Now here is a bit I have found that may well save a multiplicity of different battery types on the flight table.
Using Li-Po's to power your receiver and transmitter! Advantages:
 Li-Pos are always ready for use, they have hardly any self-dischargeThey're lighter than equivalent capacity NiMH They wont drop voltage to the level that the radio may stop working. Larger capacity means longer flying sessions. Li-Po batteries are getting cheap - cheaper than NiMH batteries in some cases. Disadvantages:
Li-Pos need more care needed when handling - especially charging/discharging. Other components are generally required to adapt to purpose. A Li-Po compatible charger/balancer is required.Before we get stuck in, lets do a brief, and hopefully simple to understand overview of our needs, and how the normal set-up operates
The average club-size model has around 4 or 5 standard servos, powered, along with the radio gear, by a 4-cell (4.8V) nickel battery pack, of maybe 1000 - 2000 mAh capacity. Some set-ups use a 5-cell battery (6V) and it is generally the servos that must be checked for compatibility with this higher voltage
A single Li-Po cell has a nominal voltage of 3.7V, this means the average middle road voltage of the cell, fully charged it is 4.2V and when empty, approx 3V. Nickel is 1.2V nominal, 1.4V full, approx 1.0V empty.
It can be seen therefore that a single Li-Po cell is too low a voltage to power our radio. Two cells together in series, is a bit too high (8.4v when fresh off the charger) so we need to adjust things a bit. The normal way to achieve this is with a device commonly known as a B.E.C. (Battery Eliminator Circuit) This component is basically an electronic regulator which can receive a varying level of 'Input' voltage, but always supplies a steady (usually fixed) 'Output' voltage.
BEC FOR ME?
There are things to watch for when choosing such a device - one obviously being that it supplies the correct output voltage required. Many have a little switch which can be set to give either 5V or 6V but we will aim for 5V for now, as this is approx the voltage from a loaded 4 cell nickel based battery after charging.
Another factor is the current capacity of these devices. Many cheaper and smaller ones can only handle 2-3 amps. I would say that for most everyday types, a 5A capable device should be fine.
So, having got our BEC regulator, we hook the input to our 2s (8.4V when full) Li-Po pack, and the unit has a fly-lead with a plug on the other end which simply plugs into our receiver where the battery normally connects. Voila!
Having previously suggested that you should use a 5A capable BEC, I have actually just installed 4A versions in my last two conversions, but as they are not 3D extreme machines, and no digital servos I am happy that this current handling limit is fine. These particular devices also have a great built in extra. A loud, low-voltage warning alarm.
Now, I should return to one of the claimed advantages listed earlier: “They won't drop voltage to the level that the radio may stop working”
Now this is potentially true because in the case of the flight pack system, the BEC device I use has a low voltage alarm, which sounds when the pack drops to 6V. This is really good news for 2 reasons… 1) 6V is the level at which our 2s flight pack should be recharged, Li-Pos should NOT be allowed to drop below approx 3 volts per cell as this can do irreversible harm. 2) Even at this 6V level, the BEC device is still supplying 5V to your receiver and servos - which is about the same as a fresh nickel based pack!
So effectively you never have a flat battery onboard.
Just another note of caution, please remember to disconnect the onboard pack at the end of your flying session, to avoid the possibility of a very small trickle discharging of the pack which could allow the battery to fall below this critical 6V level. This is just good practice really, as in all electric flight procedures. Also remember to use a good Lithium capable charger for any Li-Pos. A balancer with the correct multiplug fitted for your chosen pack is another worthwhile investment.
Tx details next time, I know you are all hanging on every word.
As always FLY SAFE. Stu'
|
May 07
BMFA club affiliation No 0340
Hi all, just came back from flying (Sunday May 20th). The weather today was absolutely perfect for flying. There were eight people there - not many considering we have fifty members in the club and it's an absolutely perfect day! Also considering that the weather has been horrible for the last two weeks.
As Safety Officer there are no incidents of any dangerous flying or people acting daft. Just a couple of reminders to all members that you must at all times avoid flying over the cars. I have noticed that the people who do this are good flyers and have no excuse for this at all. Just one other small complaint; I have noticed that when people are flying together they are not standing together. It is advisable to stand together so that you can communicate with each other on what you are doing and where you are flying, especially when taking off or landing. That's it for the moaning!
I have also noticed today that the fishermen are out in force. They held a match on the dead arm of the canal but luckily finished at 12.30 pm so this was no problem as we can't fly until 1 pm on Sunday. Please be aware that the might turn up to fish at any time so try to give them a wide berth when flying.
On a flying note, we were having great fun today. Myself and Bob were flying two scale Cub's. Mine is new and has only flown twice and Bobs is quite old and flies absolutely brilliant, slow and smooth. We were flying around in formation. It was noted by other members they haven't seen a Cub flying in quite some time and it was very rare to see two flying at the same time. My Cub has a seven foot span and has no dihedral, this means when trying to land it can slide sideways, in order to stop this rudder has to be used as well. My Field Force Nine Transmitter has a mixing program so this is not a problem. This makes landing quite straightforward.
The flying field is looking great after all the rain we have had in the last two weeks. If you have all been looking at the website recently you may have noticed my ugly mug has been turning up all over the place. This is getting embarrassing, there are an awful lot of other members in the club with nice planes but we don't see a lot of you at the field and it would be nice to see some of your planes and ugly mugs for a change and maybe we could get some of your pictures up on the website.
For anyone who may be interested we are currently trying to organise a barbeque one night in the next few weeks. If you are interested can you please get in touch with me as soon as possible so we can fix a date.
The AGM meeting is coming up soon. This will be held on the 9th June. I have attached Mike Pearsons financial report for you all to have a look through.
Fly safe, happy landings.
Miles.
|
 May 06
BMFA club affiliation No 0340
FLY SAFE - Fly Again
No meeting on May 1st due to the Bank Holiday
Next gathering at St Andrews Rugby Club June 5th - Monday
In the quest to encourage new members I am pleased to announce that the FFF website is back up and running. Many thanks Gez, I know the time and effort it takes to develop and maintain a website. So lads give it a look over at http://www.fennisflyers.org.uk/ or http://fennisflyers.org.uk
There have been good flying days this month but mainly falling in the week, but the weekends have not been great, and even when the sun has shone the wind has been decidedly cool. But decent consistent flying weather must soon be here!!!!
Don't upset the neighbours! Let this be a warning to all who have noisy engines. I hope it is something that could only happen in the US.
CHELSEA, Mich. - A man has been sentenced to six months' probation for shooting at his neighbour's radio-controlled model airplanes with a shotgun.
David Nuttle, 41, of Washtenaw County's Webster Township, pleaded guilty to one count of malicious destruction of property worth less than $200, a misdemeanour.
Nuttle used a .410-gauge shotgun to shoot at the planes. He said his shots hit only one plane, causing two tiny holes in it. The plane he is paying for crashed when the child who was operating it lost control of it after being frightened by the shots, Nuttle said.
Judge Richard Conlin of 14-A District Court in Chelsea sentenced him Thursday to six months of probation and 50 hours of community service. Conlin also gave him a 20-day suspended jail sentence, deferred as long as Nuttle complies with the conditions of his probation, which includes no alcohol or drugs and no contact with the planes' owner.
A reminder of how to trim a model and what to look for. Use the chart as you wish but remember that not all planes will respond the same, so don't try to get your trainer to complete all of the tests!!
Notes:
Trim in calm conditions.
Make multiple tests before adjustments. Continued from last month
5. Tip Weight (course adjustment)
Fly model straight and level upright. Check that aileron trim maintains wings level. Roll model inverted, wings level. Release aileron stick
A Model does not drop a wing: No adjustment required
B. Left wing drops: Add weight to right tip
C. Right wing drops: Add weight to left tip
6. Side Thrust
Fly model away from you into any wind. Pull it into a vertical climb (watch for deviations as it slows down).
A. Model continues straight up: No adjustment needed
B. Model veers left: Add right thrust
C. Model veers right: Reduce right thrust
7. Up/Down Thrust
Fly model on a normal path into any wind. Parallel to strip, at a distance of around 100m from you (elevator trim should be neutral as per test No.3). Pull into a vertical climb & neutralize elevator.
A. Model continues straight up: Adjustment needed
B. Model pitches up (goes towards top of model): Add down thrust
C. Model pitches down (goes towards bottom of model): Reduce down thrust
8. Tip Weight (fine adjustment)
Method 1: Fly model as per test No.6 and pull it into a reasonably small dia. inside loop (1 loop only).
Method 2: Fly the model as per test No.6 and push it down into an outside loop (1 loop only & fairly tight).
A. Model comes out with wings level: No adjustment needed
B. Model comes out right wing low: Add weight to left tip
C. Model comes out left wing low: Add weight to right tip
9.(a) Aileron Differential Method 1:
Fly the model towards you, before it reaches you; pull it up into a vertical climb. Neutralize controls, then half roll the model
A. No heading changes: Differential OK
B. Heading change opposite to direction of roll commands (i.e. heading veers to models & your left after right roll): Increase differential
C. Heading changes in direction of roll command: Reduce differential
9.(b) Aileron Differential Method 2:
Fly the model on a normal pass and do 3 or more rolls
A. Roll axis on model centre line: Differential OK
B. Roll axis off to same side as roll command (ie. right roll, roll axis off right wing tip)
Increase differential
C. Roll axis off to opposite side of model as roll command: Reduce differential
10. Dihedral
Fly model on normal pass and roll into knife-edge flight, maintain altitude with top rudder (do this test in both left & right knife-edge flight
A. Model has no tendency to roll out of knife-edge flight: Dihedral OK
B. Model rolls in direction of applied rudder: Reduce dihedral
C. Model rolls in opposite direction in both tests: Increase dihedral
FLY Safe, fly again and enjoy - the better weather should be here soon. Stu
|
 May 03
Free Flight Rules, Okay?
Just where are we going with electronically assisted flight? Most of us have been to shows and seen model helicopters performing amazing manoeuvres controlled by people with apparently superhuman piloting skills. But how many realise that most of these manoeuvres would be impossible without the considerable assistance of modern electronics?
Take for instance, high speed backwards flight, without the assistance of a heading lock gyro no one would be able to perform this feat. Take hovering inverted nose in, who would be able to perform this without a gyro holding the tail? Even with the model upright a nose in hover of more than a few seconds would be virtually impossible.
With a heli' it's maybe not so bad because it's all for its own sake. They are after all, amazingly boring things to fly unless you can perform a few aerobatics. Even loops and rolls become dull all to soon and so the electronic enhancement of the flight envelope becomes attractive simply because it opens up a whole new world of 3D aerobatics. So with heli's there is a legitimate excuse for the use of electronic enhancement.
Now consider the scale fixed wing model. In national competition it has been decided that gyro's are to be allowed in competing models to “level the playing field”. Oh yeah? How does that work then? Some poor guy turns up to compete on a blustery day but can't put in a good flight score compared to the other flyers because his model is not equipped with a gyro(s), even though he may be a better pilot than anyone else taking part! It's only a level playing field if you can afford it then. And how are you awarded a flying score if a box of electronics is virtually flying the thing? Also the “builder of the model” rule is to be dropped, so a mediocre pilot can buy a finished model and turn up and win thanks to plenty of money and electronics!
 And don't even start me on pattern aerobatics. The winner is generally the person who can best exploit the programming intricacies of his 9 ZAP transmitter! An exaggeration I know, but you get the drift. If I had my way they'd have to compete using a standard four channel radio without even rate switches! That'd sort the men from the (money) boys! Even fixed wing 3D models are being fitted with switchable gyros all over the place just so the owner can pretend to his mates that he can prop' hang! How lame and sad is that? A hero at any price, eh? So, he didn't build it and now he's not flying it either! I mean, what is the point unless you are controlling the thing?
I suppose the next step will be a transmitter or receiver that can analyse your stick inputs and, just like an infernal Micro$oft word processor program, carry out the manoeuvre it thinks you wanted to perform!
My God, the way we're going on with all of this electronic enhancement and other technology, such as GPS, we'll soon be able to throw the transmitter away altogether! The average club site will consist of a lot of blokes sitting in deck chairs watching their models perform some preset routine entirely alone from take off to landing. You'll be able to load in the 19xx winning routine of Hanno Prettner and sit back and watch the model perform it, just like watching a replay of some grand master chess game on your home PC!
So at the end of it all we'll be right back where it all started, free flight!
At The Field
Recently a flyer, who shall remain nameless, was observed complaining about the lack of power his OS .91 four stroke powered Acro Wot was developing. The take off run was protracted and the flight slow and mushy, and yet the motor was making good revs and sounded as sweet as a nut. “I can't understand it,” says our man, “it was fine last week.”
All those gathered fired off questions at him to determine the problem. No obvious solution presented itself. No, he hadn't done any work on the model over the week, the same fuel and propeller was being used. Nothing had changed.
Eventually it was decided that large tappet clearances were the culprit, especially as they had never been adjusted from new, and the model had done a fair bit of flying. Our man didn't know how to do this himself so someone volunteered and a feeler gauge and tools were duly found and adjustment commenced, and yes, they were very slack.
I wandered off to fuel up and fly and after a couple of minutes I heard a voice drift across, “'Ere X, this bloody propellers on back to front!” J
The farmer let cattle into the field on Friday April 4th, which caused a few hectic moments for the electric fence crew. The battery was removed over the winter, as there were no cattle in the field. When the “sealed” plastic underground container was opened to install a freshly charged battery it was found that the container was full of water and the electronic pulse unit was completely submerged in it! Erk!
Derek Kent took the pulse unit home and stripped it and dried it out, (just don't ask how!) and the next morning, thanks to the sterling work of Derek and Flymo Jeffs, it was back working! Now that was a good job - well done guys!
So be warned, the fence is now live again. Switch down is on, switch up is off. Remember, “U P** Off” J
Field Reminder
Slapped wrists all round this month. There have been a few complaints about people not using frequency pennants on their transmitters. You must use one for the safety of everyone. No excuses.
More serious complaints concern the over flying of the pit area. This is highly dangerous and should be avoided. A momentary glitch could easily result in a serious injury. Recently a model crashed in the pit area very narrowly missing someone starting his engine. Try to imagine for a moment how you would feel if your model did strike someone and injured or even killed them - don't do it.
You have all probably heard of the tragic death of 13 year old Tara Lipscombe after being struck in the face by an Acro Wot on Tuesday 15th April. It appears the owner of the model was letting someone else fly it when the accident happened. Both men were said to be in a state of shock. So… think!
A brief reminder for newer members and those who turn up to fly in carpet slippers! You know who you are…
1. Please ensure you connect the electric fence if you are the last to leave the strip.
2. Please make sure the gate is bolted and padlocked if you are the last to leave.
3. DO NOT switch on transmitters at your car.
4. Try and remember to check frequencies when you arrive at the strip.
5. Try not to over fly the canal if fishermen are present.
6. Try not to over fly horses and riders on the bridle path and in the lane.
7. DO NOT over fly the pit area.
Thanks!
The Next Club Meeting
The May 6th club meeting will be held at the St Andrews Rugby Club, Ash Lawn Road, Rugby, at 7.45pm as usual.
This month there will be a chuck glider competition.
Rules:
1. Must be constructed entirely from balsa.
2. Maximum wingspan must not exceed 6 inches.
3. No covering allowed.
4. Maximum duration wins!
You can have any configuration you like: multiple wings, canards, tandem wings, lifting bodied, discs, squares or anything else you can think of.
Previous best duration was 8 seconds. Good Luck!
Quote:
Never stop being a kid. Never stop feeling and seeing and being excited with great things like air and engines and sounds of sunlight within you. Wear your little mask if you must to protect you from the world but if you let that kid disappear you are grown up and you are dead.
Richard Bach, 'Nothing by Chance' G :-)
|