How to do a closed loop System(Push Pull) for rudder and elevator

lovely article here.

http://members.cox.net/bdfelice/Pull-pull/pull-pull.htm

Some interesting Facts about Balsa Wood

Bet you didnt know all these things hey ? check out the link below

http://web.archive.org/web/20021016081157/http://www.bomarc.com/Misc/interesting_facts_about_balsa_wo.htm

Wifly Up And Running

Hi Guys

Well. its been long time coming, but Wifly(ex Flights Of Fancy) is back up and running. products are being loaded everyday and new features are being added.
Registration on the site is still disabled but this will come back online in the next day or so

go check it out at www.wifly.co.za

Cheers
DS

Sat 23rd Jan 2010

Filled with trepidation and angst i awoke on sat morn...aahhh screw the poetry

kak week with rain expected more on fly day. fortunately none was about.
Fanie was busy mowing the runway(i kid you not) getting rid of the weeds etc, its looking good. but in some places the runway is lifting a bit. needs a second coat of bitumen. anyway care to get dirty again :) so hopefully we can do that soon.

Also started digging the foundation holes for the lapa. gonna be nice and big. provide a bit of shade. somewhere for the ladies to sit. and for us to sit during the braais.

as for flying. well it was mainly a day of helis. with the occasional interlude from a aircraft.
dennis has his gorgeous Astrohog there. brings back memories :)
I retired my Calmato low wing sportster(A.K.A trainer) after 83 successful and somewhat hair flights, with 2 midairs inbetween. Considered giving it a Norse funeral(ie light it on fire and see how far you can get) as per lukes suggestion but decided against it. flew twice. more and more stuff falling off it. went home and took the radio gear out and relegated it to the loft. perhaps oneday to see the sky again. i doubt it though.

I must admit. after all that flying the motor still starts with a back flick on the spinner. and this is a cheapie kysoho motor. im impressed. it lost a bit of power over time. but still pulled it with respect.

had 3 new heli arrivals on the scene on sat. I brought out another hk450 v1 which im going to put into my scale hughes fuz which i got from Wifly. Shaun davies brought his out as did luke

all flew well. luke had an untimely meeting with a pile of gravel though so its a bit bent. shauns flying no problem. my older hk450(the demo model) had a mishap. i took off. did a climbing turn and then lost all power. the main gear stripped and i tried to auto it in. no blade momentum left though and it hit HARD and bounced.
all thats damaged is a bent spindle and a bent frame. not bad at all. and of course the stripped main gear. Turns out it stripped becuase the motor had come loose. this is something to be aware of if flying these helis. what happens is that the plastic motor mount compresses slightly over time and every so often you should just check the screws for tightness. OR get a metal motor mount. either will work. if you get a metal motor mount dont forget to use locktite on the screws.

also one thing weve noticed is that the modern 2200ma batt is too light for these helis. they were designed for the older heavier v2 lipos. the modern v3 lipos are 20% odd lighter and hence the heli tends to be a little tail heavy. not an issue if you are just hovering but the minute you transition to forward flight it becomes pitch sensitive. tends to nose up and down.

to sort this out use a 2600ma turnigy or 3000ma turnigy(available from wifly) prices about R250 i think. added avantage is longer flight time.

otherwise a good day had by all

see pics above of the heli im building.

HK 450 size V2 heli

The succesor to he popular wifly(HK) 450 heli has just been released. its basically the same heli but they have fixed a couple of niggly problems on the v1.
for instance the tail drive shaft pinion is now better secured. as the v1 occasionally started slipping.
it features more metail bits. eg main rotor block and head button
it features a double fork tail control mechanism. this helps with extreme aerobatics as well as less effort required to move the tail rotor now. means you can use a lighter servo if you want.

the main gear looks as if its been upgraded to a stronger nylon. nothing wrong with the old one. but it did tend to strip if you overpowered the heli too much(duh....)
the main rotor block is now metal as well. no perceived gain from this for mosts people. just looks nice. for 3D is supposedly mkes the blades slighter stiffer making the helis response from crisp(A.K.A) Twitchy.

Anyway same price. R450 from Wifly. still a bargain.

see pics below.

Sat 16th Jan 2010 and club fees

well. i cant comment really since i wasnt there. So if anyone has interesting news. Email me on flightsoffancy@webmail.co.za, perhaps send me some pics etc

Remember Guys its the start of a new year so club fees are payable again. R200 Please pay to Ian Saunders.

Ramblings from The hangar 12/01/2010

So....

what will 2010 bring model wise i wonder? a fat kate moss? no man...not that type of model. i mean the flying type! well these are some of the hot up and coming items to look out for this year

Telemetry Systems
FPV Systems
High Power EDF
Autopilots

Telemetry systems is essentially a system where you can send and receive feedback from your model. sooo if you want to know your current battery voltage in the plane it would show up on your radios lcd screen, or if you wanted to know the fuel level or airspeed etc. it would show up on a screen or be outputed as a verbal instruction.
sound odd? far fetched? not really its here already. the New Hitec Aurora 9 Transmitter has it. also commercially available now are systems to plug into your exisitng radio where you can monitor battery draw, current, power consumption etc. we are edging closer and closer to full instrumentation as in full size aircraft. will it make the hobby more difficult or easier? i dunno. but i reckon its going to add a new dimension to the hobby for those who want to go down that route.

FPV Stands for (First Person Video) this is a system where you pop a camera in the cockpit of your plane, strap it to the wing or watever. hook it up to a transmitter, then on the ground you have a receiver connected up to some sort of monitor. whether it be video glasses or a laptop.
all very nice to "sit" inside the cocpit of your plane and fly but it lends a sense of surrealness to the flight unless you can look around as you would in a real aircraft....BUT WAIT THERES MORE. the latest FPV Systems have a head tracker. this is a device which you would strap to your hat/cap. it then measures the movements of your head and sends them to a pan and tilt device on your camera. so picture this. you strap the head tracker to your cap. swithc on the FPV system. and your looking forward. now turn your head slightly to the left and voila the camera turns and looks out over your left wing. etc etc. this makes the flight quite a bit more realistic. so much so that when some guys where the video glasses for the first time they fall over from disorientation

current costs for a full system is around $700. but you can build your own far cheaper

check out www.fpvvideo.com

High Power EDF(Electric Ducted Fans) are making a splash into the hobby market. with the advent of serious lipo power with high C ratings and high power Brushless motors its becoming more and more practical to have electric jets now instead of nitro ducted fan or turbine motors.
and its not just park flyers im talking about. you can get some serious power from bob violett systems. thrust in the region of 15kg is attainable. still expensive...but its getting cheaper.

Autopilots have been around for a while with mixed success. the old batch of autopilots used a optical sensor to detect the angle of the horizon problem with these was that when it got dark(dawn dusk) they didnt work. and would turn the plane upside down or watever as they could no longer tell the difference between the horizon and the ground. also. the best they could do was to level out an aircraft if it got into problems.

NOW the latest autopilots have also been designed with helis in mind. so much so that a heli poiinted straight at the ground will pull itself out and go into a steady hover if you leave the sticks go. kinda takes the fun out of it but its there to help beginners. cost is around 2k for a autoplitor system.

then the next level up is one step short of a military system. an autopilot whose movements you can plot in a pc and program into a pre defined flight plan. itll take off. go where you tell it. do something or other then come back
all on its own.
guys are using this for aerial photography on larger models.
cost is $5000+ i dont see this becoming viable anytime soon, besides. i dont know many people who would use it anyway. but its interesting to see the new technologies

begs the question though. when does it stop being a hobby and become an obsession?

How to choose and electric motor for your plane/Heli

so one question i often get asked is, how do i choose a electric motor for my plane. cos MOST electric motors(with the exception of Eflite) do not give the equivalency rating to a glow motor. they say a motor is a 41/50/8 or something which to most guys means...dick.

ok. its quite simple

Firstly se the table below to work out the power requirements roughly that you will need for your particular plane

Glider - Powered Glider. Eg lone Ranger 60-80watts per pound of weight
Trainer = High Wing Kyosho Calmotor. Thunder Tiger Pegasus etc 80-90watts per pound of weight
Sport Plane = Ugly Stick 100-120watts per pound of weight
Aerobat/Pattern = 120-150watts per pound of weight
Fighters/Scale = Spitfire, Harvard, Tiger Moth 120-160watts per pound of weight
3D = Any 3d Aircraft(Foamies included) 200+watts per pound of weight

Ok youve got a trainer. it falls into the 80-90watts per pound of weight category. lets say you work it out that your plane is going to weigh roughly 2.5kg when its ready to fly. this is equal to 5.5 pounds
So you would need a motor that can supply 440watts(5.5 x 80) at LEAST. but its better to er on the side of cauting and go for slightly more power.(you can always throttle back)
so lets use 5.5 x 90 = 495w, call it 500w

ok so now we know the power we need. but how does this compare to a .40 size glow motor.
ok quite simple. MOST 40 size motors put out roughly .8hp, this equates to 600w, remember that glow aircraft are generally heavier due to fuel and extra batteries so ignore the subtle difference.
so off you go now and look for a electric motor putting out 500-600w of power.
but now you see that there are 20 different motors putting out this power. and the only difference between them is something called a KV Rating??????

Ok this means RPM per Volt. so if you have a KV Rating of 1000kv it means that for every volt the motor receives it will turn at 1000rpm so if youre using a 3cell lipo pack which is 11.1v then the motor will turn at 11000rpm(under ideal conditions)

great. how does this equate to glow? between the .25 to .60 size area the rpm range is between 14000rpm and 10000rpm more or less. so go somewhere inbetween and you get 12000rpm

so now you now that to fly your .40 trainer you need a motor which can supply between 500 and 600w of power and a kv rating that will spin whatever prop it recommends at between 10000 and 12000rpm

so please dont go buying a motor with a kv rating of 4000 this means it will spin at 44000rpm on a 3 cell lipo pack. useless for aircraft unless youre flying ducted fan.

most aircraft use 3 cell packs. if you want to use a bigger pack, for a larger aircraft. say a 4 cell(14.4v) pack. then bear in mind it will UP the rpm of the motor. so when considering motor choices you have to look for one with a slightly lower KV rating say 750kv
this means 750 x 14.4 = 10800rpm? you see how it affects it?

anyway. post some comments if it sounds greek but the process can be summed up in the following steps

1.) Find out the type of plane youre flying(should be pretty obvious)
2.) Find out its weight in pounds
3.) establish how much power you need to fly it
4.) look fore the appropriate motor with the necessary power and appropriate kv

voila. done.

C Rating on Packs

so on sat a couple of guys were asking what the heck the C Rating on a lipo pack means. ie 20c 30c 35c etc.

Well c stand for its capacity to supply amperage. so 20 c means 20 times the batteries capacity. so if the pack is a 2200ma(2.2a) pack and its C rating is 20c this means it can constantly supply 44amps(2.2 x 20) to the speed controller without burning up and turning your aircraft into a fireball.

Now what will be the difference if you buy a 30c 2200ma pack? well essentially this
it can supply the power in larger amounts. Ie it can safely supply a constant amperage of 66amp(30 x 2.2a)

how does this affect your flying? not much unless you you are flying high powered EDF(Electric Ducted Fan) Or 3D helis which need large amounts of power in a light weight setup.

A 450 sized heli needs a 40a ESC or so. So using a 30c pack which can supply 66amp is pointless. as the speed control can only handle 40amp
In the long run you might notice that the 30c pack will last longer as its not using its full capacity all the time. but the price difference does not justify getting the large C rated packs in my opinion.

20C rating should be fine for most applications. if you need more amerage. go to a larger sized pack.

Turnigy VS Flightmax Packs

Hi Guys

As you know Wifly has both the turnigy and flightmax packs available. both seemingly identical, just the flightmax is R20 cheaper or so sometimes. ive been asked why. here is the simple reason

1.) both batteries have the same stated capacity. ie 2200ma. but if you compare them side by side you will see the turnigy is ever so slightly larger. 5% or so.
2.) when you fly them you will get slightly more flight time out of a turnigy
3.) when you recharge them the flightmax will take 2200ma and the turnigy will take 2300ma+ odd...but true.
4.) the Turnigy does not come with deans connectors. and the flightmax does.
either way they are both excellent packs.

HK 450 Helis Short term report

Ok so weve been flying the Hk450 heli for a while now. this is one of the helis available from WiFly Hobbies(Ian)
So far so good. its excellent value for money. as with all helis there are some things to take note of
1.) Unless you are just learning to fly throw the standard plastic blades away. they have a thick profile and suck at least 30% extra power. fine for learning on though
2.) Check all the frame screws for tightness when it arrives. we had one come out on the motor frame and it stripped the main gear. you should actually check all the screws on any heli when you build it. remember to use loctite on metal to metal screws
3.)If youre using the telebee gyro. remember it mounts SIDEWAYS. not flat
4.) If youre using a HK401b gyro use a fast digital for the tail, otherwise you will get wag

Remember to get yourself some nice painted canopies. they are Cheap (Between R80 and R95 rand) and the quality is very good.
when your flying improves go to the fibreglass blades(bout R60) or CF blades(bout R150 from wifly), the CF blades are excellent, in fact i prefer them to Align Blades

otherwise there are no issues to report with the heli. it flies beautifully. so much so that im going to get a couple more of them! :)

Sat 9 Jan 2010

RAIN RAIN RAIN. got there early. nice and sunny, but round 3pm 2 storm fronts hit us at once. jumped into the cars. most guys left but afterwards flying was nice. still spitting and dropping but we got some good flying in. I left my low wing trainer under fanies car. to protec it from rain but there was so much it got into the wood on right right hand wing. so when i was flying and i pulled tight turns it would stall to the right heavily and go into a spin. landed it and turned it on its side and water poured out the wing. hehe. i think its time to retire the old girl

Not much other flying went on. Most people left. I did prang louis 3D plane(DOH...) pulled a loop to close to the ground, couldnt pull out and splat. my bad....