You are invited to the next Aeronutz Fun Fly on Saturday 24th January 2004 5pm until 11pm. Parklands Centre, Wigston Rd. Oadby. £8 per flier, Bring a warm jumper as the heating will be off, tables are provided. All fliers with models over 10g must be insured. Remote control machines must have semi scale appearance - on sticky looking things please! If your are unsure please check before travelling. Max. Weight for any model will be 80g. This would have been lower but we are pleased to see the super scale Falcon kit's balsa machines from Chris at RCS Technik. News Letter Jan 04
- Mark attempts second flight with Reno Corsair
- Tiny timers with everything.
- Mark / Bob in world championship glider tow attempt
Tiny Timers On Toast
Testing testing .......... Matt writes "this is my little test plane for Nick Leichty's, 3 channels, 27MHz system. It's 6.5 inch span, 6.5 grams. Etec 90 cell, and motor from an old Wes 2.4 servo. First flight attempt showed trim problems, so we'll give a try again tomorrow. Various thicknesses of foam sheet, some from Kenway. I'm calling this one the 'Light Mite'."
New 35MHz Rx. Falcon models are about to launch a new Rx. It will be very light and drive servos initially but hopefully the reseach laboritory behind the project will do us outputs for actuators. Its very good to see some new 35MHz Rx's coming along. Maybe a Schneider Supermarine challenge down on the south coats in the Autumn? 10g flying weight should be plenty
Wanted: Several years ago Potensky made some little servos to go with thier super 4 channels 35MHz Rx. These servos have little iron core motors that are quiet high resistance makign them ideal for high voltage use. We are thinking miro ducted fan etc. Let us know if you have any knocking about looking for an F18 or Euro fighter.
Wanted. Anyone know where we can get some 30 tooth gears that can be fixed to 20 thou' music wire (0.51mm) prop. shafts? I was thinking brass gears migth be good as we could glue 'em on? Or solder then? These are for the next generation of micro planes ....... 5 and 6 gram Corsairs etc. The idea is to make thinner, lighter props from styrene sheet and then use 20 thou wire prop shafts glue to the prop. The shaft then goes through the gear and through the tube bearings. The shaft is fixed with a plastic tube thrist washer at the back. This should be much lighter and the prop will be more flexible so it don't rip the motor out the plane! The prop. will handle about 4g of thrust at the most.
Caution: This news letter contains few nice pictures and goes on and on about boring technical stuff. Readers are advise to give up and watch TV. Even digital, wide screen Dads army repeats will seem intresting if you look for the continutiy errors.
Caution: Boring techinal item A.
If you want to fiddle about with Flexinol, coil actuators, testing motors you will need so specify a voltage. The following dull circuit allows you to select a voltage from 1.3v to 10v by turning the potentimeter. Not as exciting as a Lara Croft interactive video game, but it is nice to think you have managed something electronic without killing anyone. Total cost of the parts is about £3. You can use any DC output transformer that generates as much power as you are likely to use. I have a 12v Maplins transformer that can do 1 Amp. You could use a transformer from a Dremmel drill? 18 volts is Ok.
This is more interesting, Chuck sends details of his super looking B17. Note the unusual colour pencil? "MyR/C B-17 is made from a Carl Goldberg "Airwings" profile glider. Weight: 55 grams Wingspan: 430mm (17 inchs) Power: Four direct drive ultra-high resistance M-20 motors (each motor draws appox 300 ma at 4 volts) All four motors are in parallel and all turn CCW so total current drain is 1.2 amps at 4 volts Props: and pencil from Matt. Battery: One E-Tech 250 mahr Li-po Flight time: 4 minutes and 30 seconds timed outdoors (Indoor flight in Burbank gym was not timed ) Radio: Micro Joule 4ch recr with GWS crystal on 72 mhz ESC: Custom ESC by ARCOX -cutoff 3.0 volts with 4 to 5 amp capability Servos: Two Falcon 1.7 gram servos Pushrods: 0.5 mm brass rod Controls: Throttle,elevator and (strip) ailerons coupled to rudder Ailerons are set down about 3 mm as flaps( Top of wing leading edge is sanded down and back about 12 mm to create a small airfoil) Flies very well wih coupled rudder .Does not fly as well without rudder. Feels nice in the air but have not tried a LOOP. Enjoy!!! Chuck
Well they look like Matt's props but that pencil sure dont look ike Matt's from this angle? I saw it at the NEAT Fair in September, sure looked a lot more orange then. I'm sure it was Stabler H7? Not the ones with the rubber in the end though (loosing the will to live?, Dad's Army must be on one of the 238 channels somewhere Ed)
Voltage Switch
If you have a plane that is very effecient it will still be flying below 3v. 12 months ago Mark got a tiny ciruit to switch on an LED at 3.0v to want R/C pilots its time to land. This circuit then stopped working. It now turns out his multimeter was not working properly and Farnell's catalogue information is wrong!! These problems have been descovered and rectified. So now we can switch at 3v again. The simplest way is to switch on "landing light" which is a compact red flashing LED. Mark original 10" Jigglet had one, at 3v we coudl throttle back and switch the LED off again !! The Jigglet was still up in the roof flying horizontal when it was at 3v. Which reminds us this was the same problem the 14" Albatross had with WES Tech servos - which would zoom off to one end when they died! Not helpfull. Which is when we started using Z Tron IR and coils. The parts used in the voltage switch are cheap but you have to buy lots get get the minimum order value. Mark has bought lots of parts so it would be easier to buy via Aeronutz. Voltage switch and flashing LED complete and assembled £3 each profits to Aeronutz. The chip used is SOT 23 size so it weighs practically nothing. When used to drive a small pager for retracts a capacitor is require, the motor upsets the voltage switch (Back EMF?) Here is a sketch of that test circuit ............
Here the flashing LED is switched off at 2.95v Latest version switches at 3.1 volts, which leaves time for a nice circuit
Last month Aeronutz lacked any long range recon capacility. With the new Corsair's just sitting around on tables it was obvious a sneak attact could cause considerable setbacks to indoor micro plane develpment. So this month Mark has put his original free flight Catalina into the workshop to be brought back online. The nose was pretty chewed up so it was decided to fit a new one. Having the original patterns is very helpfull. So! cut off the nose at the blue foam bulkhead, re-use the cockpit, noseblock and front former. Draw out some new sheet parts.
Glue on the top, glue on the two sides. Squidge it about a bit with your fingers .........
The 22" Catalina will be powered by WES Tech 3 0.15 iron core motors from Falcon models. These weigh just 2.4g each and produce plenty of grunt and have 1mm shafts so we can just push fit the grey Potensky props for (blissfully quiet) direct drive. 145mA Kokam gas tank should give plenty of range, crusing up in the steelwork. Z Tron Twin motor steering is all that is needed to miss the walls.
Above. Mark's test of the U80 with 4:1 geared Didel 4mm pager (13 Ohms) shows some promise. It's eas to make, cheap and weighs just 1.71g at is it shown top left. Running directly from a transformer it achived 2.8g of thrust at 3.3v for 165mA of current. At 4.7v supply it ripped the sky appart with 4.75g of thrust for 230mA. The U80 was turning a bit slow so maybe a little more pitch if you are trying to use the 90mA cell? Mark will put this one in the new PZL Wilga with a 40mA cell to test Bob Bailey's BBA Flexinol actuator. 40mA migth be overloaded a little, where or where is that 60mA cell?
New carard
John has been playing with f/f canards all winter, this one is Mark's version which was successfully trimmed as a glider. It has now been fitted with a 4mm pager and Ikara prop giving about 5g of thrust. It will be interesting to see if it will climb. Another step towards the F18's .........
Free flight goes Lithium
Last month we covered Andrew H's F/F timer which allows us to use Lithium Cells. Your editor completly forgot about that and re drew it all again - doh! So here it is again. Mark has since made some and they are great considering the cost / efort and weight. Mark's use super small surface mount components, The output transistor is size SOT 23 and the resistor and capacitor are so small they fit between the transistor's pins !! Nope it aint heavy. The transistor can handle a massive two Amps!
Mark found that by using a massive value resistor we can get a short full power run and a slow throttle back. This should give a nice flight similar to rubber power characheristics? We will see on Saturday.
Circuit taken from articles by Robert Pearce (EFUK issue 39) and Rainer Krafft (Model World April 1997
Below: This is a the finished timer. If you charge the capacitor to 2.7 volts (two AA cells) the motor runs at full power for 35 seconds then starts to slowly loose power until 45 seconds when it drops down noticably and then runs slower and slower until it stops at 85 seconds. Should be a nice flight if you can keep the plane crusiing in circles and your plane is a tad under powered. If it is not underpowered you could reduce the full power period by charging the capacitor to say, 2.3v. Or just launch the plane after a few seconds. Depends on the plane etc ........ In this version the resistor is 18 M Ohms and the capaitor is 3.3 uF. The transistor has been tested up to two Amps so no need to worry about damaging that little chap then!
The 3 parts used for the timer weigh 0.02g
The two planes below are free flight electric using lithium cells and Andrew's timer'ses'ss.
Left: Regulars will instantly recognise the style here .... Depron and lots of bold colours
it's gotta be one of Barry's twins. Right is Andrew's York blue foam multi
R/C Model Flyer have details of Mark's APPA Flexinol actuator in this month's issue
Mark is playing with a DIY Vac former to see if we can use styrene sheet to make very light props? More details later
Warning: Conceptual geometery is everywhere!
Square-you-like Oil rig, tee pee, satalite dish? Nope. If we want to put a prop shaft on the back of a propellor we need to get the shaft square to the prop in both directions. So, is each of the three legs is the same lenght, and the 20g SWG wire is touching the centre os the circle it would be reasonable to assume it is all square up to the 1/2" thick plywood? If the three legs are long then the inaccuracy will be small. So if we fix the prop shaft to the prop with a long piece of 20g wire and then cut it down to length our shaft should be pretty accurate considering the amount of time and money spent?
Add a solid tower Fix "Vee blocks" to solid tower
Tilt jig through 30 degrees
20g wire now rests in Vee block
square to plywood base
Remove the three legs Vee blocks are pieces of brass rod
one above balsa and one below so you dont
make a corner for the 20g wire to get stuck in
Bernard reports that the new Collall foam glue from Flitehook is very good, almost the same as good old Bison. Suspicions are that it is Bison ! Well same formular differnt company?
New ! PZL Wilga
So thanks then to Bob Bailey in Florida for not only inventing but then posting Mark a BBA double Flexinol actuator. As it has evelator and rudder it migth be nice to put it in a high wing stable model where we can check out the flying qualities. But then it would be nice to do something usefull with the elevator ......... so how about some Aerotowing? A little stall allways helped release the glider way back in the free flight days and would be good for short landings in small fields too. Did you see the rise off table aero two in the hangar at the Barkstone Heath Nationals that time ........ wow, you had to be there!
Here is a picy of the original F/F rubber power Wilga
The new three channels version will be the same size, 8" span, 40mA cell, BBA actuator, U80 and 4mm pager geared 4:1 as above, Z Tron infra red three channels, propotional. Hopefully the flying weight will be 8g so we migth get 50 percent pwoer to weight. Stalky undercarriage give plenty of prop clearance.
If the Wilga goes well maybe we could use Nick's super light 27 MHz R/C for a glider? Rudder only, Minimoa, K13?
Andrew H is doinging some tests to see if we can use an altimeter for F/F planes ......... a sensor looks down and shuts off the motor when it gets dark. Sounds easy enough? Until you define dark .......
Starting in the Autumn we will reduce the maximum flying weight from 80g down to 40g. It's easy to make a nice little R/C plane at 40g, you should be able to do that with stick and tissue. Graham's Gemini twin motor infra red plane only weighs 15 grams !
Pagerhell : Mark has been testing pagers, props and gears, A new web page is available with confusing data that will be straightened out a bit in the near future !
Maplins are selling multi meters for £2.50. That's silly money. You can't buy the leads or the box for that. Might be as well to buy a couple to use the LCD and current / voltage meter for charging NiCd cells or making variable voltage cicruits?
Maplins multimeter
madness
