Відео

It's an adaption of the circuit detailed by Chris Stoddart in the 2020 NFFS Symposium here: www.freeflight.org/complete-symposium-contents/

@lpense8510 I make them myself. They are based on the push button version of this circuit: peterboroughmfc.org/technical-articles2018/FET_Timers_consolidation.htm but with smaller components and on an etched circuit board.

It's in the current AeroModeller - May 2024 Issue :)

It starts the motor an stops it again

@marcinlipinski1149 Thanks, the circuit is described here: peterboroughmfc.org/technical-articles2012/11ModifiedFETtimer.htm but I haven't published the etched board pattern anywhere - it's fairly simple though. The MOSFET is a SOT-23 package, there are many suitable but AO3404 is a common cheap one allowing up to 5A current. The capacitor is a tantalum 47uF B-Case. The trimmer potentiometer is a 1M ohm Bourns 3313J-1-105E - possibly a bit pricey now but if you don't mind some extra weight then there are lots of cheap 6mm trimmers available. And yes this replaces the resistor to give variable time. The push switch is a 6x3mm tactile momentary push-to-make SMD from ebay: www.ebay.co.uk/itm/223869218283 Lots of similar available. I added a 100R resistor to protect the switch (limits the current accross the switch while charging the capacitor) but it's probably not needed. Yes, it works as a monstable, it's the same as the original design but using the onboard Lipo to charge the capacitor instead of an external 9V zapper battery. Hope this helps, feel free to ask more questions if you need to...

Thanks a lot! I run a modeling workshop for children and I would like to build simple models with them using XPS foam. I initially chose the supercapacitor based drive method, but now I see that a fet timer is a better solution, provided it can be operated like yours on the Twin DC-5.

@@marcinlipinski1149 If you would like to contact me by emailing the Peterborough Club, I will send you the circuit board details. Jon

@linsfunbox4952 This one is a Turnigy Nanotech 1S 210mAh from Hobbyking. They are discontinued now I think but sometimes come up on eBay or hobby shops. There are lots of similar small one cell lipos available for small drone fliers.

@@slowmatch7612 Thank you!

@linsfunbox4952 I think this one would be an Eflite 1S 70mAh from their mini RC models such as the vapour. But any small one cell lipo should work.

@@slowmatch7612 Thank you for your replying. I tried to use a fully charged 551521 3.7 V lipo to connect to a 3.7V motor with JST, but it was not working. Only ran for 1 second and stop. Not sure if I picked a wrong batteries. This is what happened when I connect lipo to motor... ua-cam.com/users/shorts7Ao4u8hs4Wg

@@linsfunbox4052 Unfortunately that battery is intended for long duration, low power applications. It has a discharge protection circuit limited to 0.12 Amps current. Your motor will draw more like 1-2 Amps so it triggers the cut off. It is possible to remove the small circuit board in the battery but it's a fiddly job!

@@slowmatch7612 Thank you so much! I think I will pick a right one for motor. It is not safe to remove something from battery. Thank you!

@@linsfunbox4052 the circuit board is not within the battery capsule, just under the yellow tape. But yes, obviously it's wise to be careful and not do something you are not comfortable with. Look for batteries with a 20C rating or more - the Eflite and Nanotech ones do not have a protection circuit. The circuit is not a problem as long as it is rated for the current your motor draws, for example: www.micronradiocontrol.co.uk/lipo_1s.html

You can't ;) I designed and built it...

It's just a timer I built myself with a 1S Lipo and a 8.5mm Coreless motor.

Yes, no problem.

thank you very much for your help! 😁

Hi Andy, have a look on Ebay and search for "N60 25500RPM Motor" and you will find some available from China for a couple of quid. The original GWS CN12 was slightly better but this is a reasonable replacement. If you're struggling feel free to get in touch with me via the PMFC website and I'll send you something. Are you building a Ferry 500 specifically?

@@slowmatch7612 thankyou, I'll try there, yes I'm going to build one with my grandson, he's starting to show some interest in flight and i can't wait to show him how cool it is.

@@1410walt They are a lot of fun! I hope you both enjoy it. PS there is a Facebook page for E20 if you're interested: facebook.com/groups/252734703568141 Jon

@@slowmatch7612 I've downloaded the plan and going to see if i can print it off. Thankyou

Hiya, yep I have been looking at the ATtiny85 but I'm no coder...yet!

Yes, I think so - it was hard to get a consistent flight pattern with the wing warps.

@@slowmatch7612 Thanks for your reply.

I designed and made it myself. I do build a few timers for people commercially but these are fiddly and expensive. Where are you based?

@@slowmatch7612 based Uzbekistan

@@slowmatch7612 will not you share one of your timer designs?

@@deltaslope1422 There are some of the simple timer designs available on peterboroughmfc.org/technical-articles2018/FET_Timers_consolidation.htm

@@slowmatch7612 very kind of you!

This is a converted rubber powered plan :) I've built a few of the Junior Series as rubber models and they are fun if built light enough.

In the end I didn't pursue that circuit as it had some issues. It needed a fairly large battery to be reliable and it didn't work well with onboard supply for an electric model. I have since developed more reliable DTs based on a double 555 Timer.

Oh... they are actually birds? Sparrows?

ua-cam.com/video/YYVJlxg85yk/v-deo.html

Yes, no problem with this circuit and components.

Trade secret I'm afraid ;) I will publish details as soon as it's finalised though.

@@slowmatch7612 I look forward to trying it myself, I suppose if you told me now you would have to shoot me.

Hi Urs, this one has flown in my 13" DC-5 Twin. The E20 Timer is yet to be flown :)

There was zero discernible wind at ground level on this day. Very few Free Flighters that would think launching downwind is a good idea...

that is a cool story!! :)

ua-cam.com/video/YYVJlxg85yk/v-deo.html ;)

Hi Pat. The motor/lipo circuit does not run through the trim pot - it runs through an LDO Volt Regulator chip. The chip has a variable output voltage determined by a feed back pin. The trim pot sets this feedback voltage and carries virtually no current. I've added a link in the description so you can see more details including the circuit diagram.

@@slowmatch7612 That is really helpful, thank you ! I am on HPA also so will check back in through there, appreciate the feedback Pat

What components did you use? To get more time you need either: 1) A bigger capacitor (higher uF value) 2) A bigger resistor (more ohms) 3) More voltage in the zapper (up to the capacitor max voltage obviously) - check your 9V battery is fresh. The voltage in the circuit (ie 1S or 2S lipo) shouldn't make much difference providing you have a suitable FET.

My friend has had the same problem. No big deal. The timer is great with a bigger resistor and a 500k trimmer. I’ve made several now