X-Twin, Aeroace - post your mods, links etc.

[epilot]

Hi All

I though I would get a thread going about the Silverlit X-Twin. There is already a thread: http://www.rcgroups.com/forums/showthread.php?t=382167
but the title does not say which model it is about and it has mainly been concerned with availability.

I propose we use this thread to share links to information about the models, possible modifications and scratch-built models that uses the X-Twin R/C equipment.

There are currently two models in the range; a monoplane and a biplane. The ones I have seen so far are all on 27MHz but are designated "A", "B" or "C". They rely on digital coding/decoding and have no crystals. This means that 3 can fly at the same time.

The models are currently available in at least a couple of European countries in Toys'r'us stores and from Internet stores. It looks like they will be released in the USA by Airhogs under the Aeroace name:
http://www.airhogs.com/airhogs/aeroace.html

There is a forum for these models in Germany:
http://www.nottoxic.com/wapcc/xtwin/bbs/index.php
It is possible to post in English. In this thread there is a nice video of the models flying indoors: http://www.nottoxic.com/wapcc/xtwin/bbs/viewtopic.php?t=27

Some modifications have been posted in other threads but it would be nice if you could post your modification here with a short description of what you changed and what effect it had on the flying qualities of the model. Picture would be nice too.

I have a couple of the X-Twins and a set with the biplane on the way. First impressions are good and I hope for a spot of nice weather this weekend so I can test fly. I won't be able to make any modifications for a while since I will be moving shortly and all my workshop equipment is in boxes.

The R/C equipment lends itself well to experimentation and it should be possible to build light profile scale twins from Depron or balsa.

Hope to hear from a lot of X-Twin owners so we can give the Bit mod thread a run for its money :)

Michael

[aerogel]

I have yet to see one of these in the u.s where can you get one?

[epilot]

There is already a thread: http://www.rcgroups.com/forums/showthread.php?t=382167
but the title does not say which model it is about and it has mainly been concerned with availability

It looks like they will be released in the USA by Airhogs under the Aeroace name:
http://www.airhogs.com/airhogs/aeroace.html


Sorry, but I can't say it much clearer than that ;)

Michael

[micro_builder]

Michael,
Good timing on this thread, as i just finished my own Bipe for use with the stock bipes electronics. i started to have reservations about stripping the bipe, at first i didnt like it as much as the Eagle wing, but after getting to fly it in dead calm air, i realized that it was a very nice flyer. its turns are much better and there's more overall controll. i think the Eagle wing can fly a bit slower though. but, i had to build something for it. i did some other mods, but they're in the other thread you listed above.

the bipes fuse, wings, and tail section came in at around 9 grams, all the electronics + lipo comes in at 10 grams. i was surprised the fuse weighed almost as much as the electronics.

anyway, i split the bipe again and removed the electronics and set them aside. i then built my CF and balsa twin boom bipe. its technically a staggerwing, as the top wing is a bit further back, but not much. 9" WS, 2.3" chord, bare weight of 3 grams (as much as just the top wing of the stock bipe).

transplanting the electronics was about as easy at it gets. the motor holders have a flat side for easy flat mounting, which also had some two sided tape on it, so i just stuck it to the underside of the top wing along the wing rib, which gives it a few degrees of down thrust. the lipo sticks out on the little CF rod which also acts like a bumper of sorts during crashes.

i came out with an AUW of only 13 grams. not bad, i wish i had 2 4mm pagers with appropriate props so i could use a 60 or 90mah lipo to really put the weight down. i've yet to be able to sucessfully fly either the Eagle wing or the Bipe indoors, but this one might be able to.

the winds are too strong right now so its maiden will probably be a little later tonight. it glides very well, i hope it flys just as nicely.

nick

edit: i'm pleased to see that AirHogs is getting these planes on their line of products. if they dont mess with anything, they'll be the best plane they've ever had - and i've flown a lot of them, usually just bricks with wings :rolleyes:

[FFFlier]

When someone eventually takes theirs apart, I would like to know how heavy just the receiver is.

Thanks,
Bill

[micro_builder]

Hi Bill,

i havent unsoldered any wires off the PCB yet, so everything is still on there, BUT, the lipo weighs 3 grams, the two motors+props+motor case weigh about 5 grams or so, so i believe the RX is around 2 grams (others have said this as well). this is inline with the AUW of the electronics of 10 grams.

i could be off, my scale is only accurate to a gram, and it seems like the rx should weigh less than 2 grams, maybe someone else can give a more accurate weight breakdown.

i got a chance to try my home-made bipe this evening. it took a lot of adjustments here and there, more so than any of my other planes. the incidence angles, motor angles, tail feather angles, not to mention finding the CG on a stagger wing biplane - what a pain. but, it did eventually fly, still a bit too tail heavy, but thats easy to fix. turns are no problem, tighter than the stock bipe/mono too. this was my first succesfull bipe, first successful pusher setup also, i just might have to add this one to the working pager powered models sticky.

nick

[FFFlier]

Sounds great Nick, good job on the bipe,
Last bipe I made was a peanut Sterling Jenny about 20 years ago. Shows how much I hate trimming 2 sets of wings.

Bill

[Pjotrrr]

Replaced the tailboom and plastic parts for a 1,3 mm carbon rod, saved me 1,4 gram
Added 2mm LEDs parallel to the motor-wiring (0,2 gram)
Video with pictures of parts on scale:

http://194.109.150.81/Web/Upload/Pjotrrr/XTwin.wmv

As you can see it can be "flown" in a 4x4 meter space with a lot of left rudder ;)

Peter

[aerogel]

Kewl vid thanks peter....Nice plant : )

[CAFplanekid]

has anybody found them in the US yet? I am going to run by Toys R Us later today, and buy one if they are there. I think I am going to build a 1/32" balsa/ grocery bag wing and tail group for it, I think I could get one to about 2 grams at 15" span.

Jonathan

[micromad]

They will be sold soon in Britain from: Maplins (http://www.maplin.co.uk/module.aspx?ModuleNo=47500&doy=). :)



Alex

[epilot]

Making it lighter will make it fly slower but not turn better because it relies on differential thrust for steering. This might be the deciding factor for how small a room you can fly in. Moving the motors furter apart would of course help but might make trimming more tricky.

I have measured the motors to be 5.3 ohms. On a fully charged cell the current draw is 390mA. This would mean that the props might be a bit too much for the 4.5ohm pager so they would need a bit of trimming to be used with this motor (unless you don't fly a lot at full throttle)

The receiver including antenna but with charging socket and switch removed weighs 1.35 grams.
Motor with leads and prop weighs 1.83 grams
Cell weighs 3.8 grams
Fuselage pod 1.4 grams
Wing 3.42 grams
Stab/rudder 0.71 grams
Tailboom assy 1.8 grams
Motor mounts 0.42 grams

This means that with a plug added for the cell/receiver the equipment weight can be as low as app. 9 grams.

One of my X-wings will receive a JMP or Plantraco RX transplant and an actuator for the rudder.

Michael

[epilot]

Alex, good find. Typical high UK price though :( I paid EUR 27.99 at TRU here in Germany and there are shops that sell them for as little as EUR 19.99. Online you can get them for EUR 25.00 and EUR 29.00 for the set with two models and one TX.

Michael

[micro_builder]

Michael,

thanks for posting the weight breakdown and ohms/current draw.

after putting a few days of flights on the planes, i've found myself rarely ever going full throttle. most of my flights tend to be head-level which only requires the lowest level of throttle input, which makes for nice long flights.

my motors are about an inch further apart than the stock on my bipe, which accounts for its better turning radius, as you mentioned. i hadnt considered that the further apart they are the more difficult it might be to trim it. i'll have to remember that.

i think i'm starting to wish i had waited a bit for AirHogs to get these planes in. i dont know what the currency conversion is between USD and EUR, but i paid 110 dollars, including shipping, for my two plane set. oh well, its the price you pay to be the first on the block with a new toy :rolleyes:

nick

[poulsbobill]

has anybody found them in the US yet? I am going to run by Toys R Us later today, and buy one if they are there. I think I am going to build a 1/32" balsa/ grocery bag wing and tail group for it, I think I could get one to about 2 grams at 15" span.

Jonathan
I called the phone # that was in the backyard flyer ad and the guy told me he had no idea when they would be in the U.S. He was supposed to call me back when he knows...3 days ago.

Looking forward to giving these a try!!

Bill

[Malmen]

If there are any swedes out there looking for this model, I can inform you that I bought one at BR Leksaker for 199SEK (22 EUR). Flight characteristics are entertaining, espacially if there is some wind, plane seems virtually indestructible. I let my girlfriend try it, resulted in some treeclimbing, no damage to the aircraft or the climber thogh.

/Malmen

[epilot]

How do you like the model itself? I can't decide if it is ugly or not but I like the crashability and the paintjob is not bad either. That is why I think it would be worthwhile to fit "proper" R/C and use a singe motor (7mm pager or M-20) and add a rudder actuator. The ideal "knock-about" model. I found that 2mm Selitac (un-sanded) is lighter than the material used for the tail so with sanded Selitac you could get the weight down to 0.5 grams. One of the Germans sanded the paint off and that made the model 1.2grams lighter. I'm keeping it on though.

Michael

[Faronas]

Hi Michael et al,

Like the bitcharger thing I think, they are a nice primitive toy to have fun with, so we're working on it. I made a new project site on the Team K homepage :

http://sport.unisport.etc.tu-bs.de/~modellflug/klaustrophobia/klaust.htm

We're focussing on indoor pylon. The x-eagle is the fist model to do "one design races" right out of the box with. Problem are still the three frequencies, so you are limited to the combinations of pilots.

I think the main problems with the x-planes are as follows:

- at the range limit, they go on hold, which means in a climbing flight, that you'll lose the plane

- the planes are unsteerable in gliding flight

- the motors are too strong to lighten the plane. The x-eagle even rises on the lowest throttle position.

During summertime (no, it's not raining season in Germany), i'll try some parkflyerish models, during winter, I'll focus on pylon racing.

So long,

Patrick

[epilot]

Patrick, I have some 10 ohm pager motors that are a bit longer than the ones used on the Eaglewing. They might be a good substitute and the extra weight can be compensated for by using a lighter tail boom. That will allow better use of the throttle.

Your new webpages cannot be viewed with Mozilla Firefox directly because of the \ used in the URLs.

Michael

[Faronas]

Hi Michael,

good point, I just corrected it, should work by now.

I don't think that10 Ohm motors would be the best choice, as they are equal heavy, but weaker. Why not take smaller motors ? (not knowing the pager motors market..)

I just disassembled my X-Twin. It's nice, you can completely take it apart without damaging any part or needing any tools. Just take soft violence and star on the end of the fuselage.

So long,

Patrick

[epilot]

Patrick, with appropriate lightening of the model and the 10 ohm pagers you would be able to use the throttle better. You mentioned that it climbs even at the lowest throttle setting with the original motors. It would be an option to fit some of the long can 4mm motors but there are no commercially available props that I know of. I make my own.

Michael

[peter frostick]

Micromad/Alex
Thanks for the info regarding this aircraft being sold by Maplins --- we Brits seem to miss out on many RTFs available elsewhere! Lots of dollies and no planes!

Peter

[micromad]

Thats all right Peter, we just have to wait for maplins to get a batch in.


Alex

[micromad]

I have found this on koichi's site (http://babelfish.altavista.com/babelfish/tr?tt=url&url=http://blog.goo.ne.jp/toko0131/&lp=ja_en)



Alex

[epilot]

I just flew my bipe which arrived today. It was very windy but between gusts I was able to do a few nice circuits. It needs a bit of noseweight but other than that there is really no need to modify it. When freshly charged it flies on the lowest throttle setting. I don't like the fact that it cannot be controlled with throttle off so if the wind takes it you have to power up and hope it will spiral down.

I find that you can get the monoplane airframe down to app. 5.5 grams. With a light Plantraco receiver, a 90mah cell, a light actuator and one of the original motors it should be possible to end up at around 10 grams. I think the original motor might just be strong enough to fly the plane indoors. Place the motor at the centre of the trailing edge. It would make it a very robust trainer.

Michael

[micro_builder]

question: what would happen if i were to reverse the polarity on one of the motors so they both spin in the same direction?

the reason i ask is because i'd like to try using the Aero-X props, just to see the results, but they're not counter rotating as the stock ones are.

i dont know if the plane would want to turn more in one direction if the props spin in the same direction, so i thought i'd ask before i start any soldering.

anyway, i found that you can remove the bottom two wings of the bipe and fly it as a mono. its a bit quicker but the turns seem just as sharp. i also found that you can take those two wings from the bipe and stick them onto the Eagle to make it a bipe. i didnt really see much difference with the Eagle being a bipe, but, depending on the incidence angle it'll climb like mad, or it'll tip stall very easily. i'm keeping the bipe as a mono for a bit to play around with it, but the eagle is staying a mono, it doesnt need anymore help in lifting (i never thought i'd be "upset" with a plane for climbing too easily).

nick

edit: i've been flying the bipe as a mono all day today and i like it more than the bipe or the eagle. it turns sharper than the eagle, when the battery starts to drop the plane will actually come down on the first power setting so you can actually controll the plane as it decends, and it seems to handle the wind far better.

[derk]

michael, could you use the 4mm motors and make 2 gear drives to use the stock props? may save a bit of current than using them dd.

just a thought.

[brucej]

For those in australia you can buy these at Toys r us

[Hotflyer]

Anyone with one of these bipes has to try this! All you do is get a good straight run at a newer car with smooth paint and try to aim for the sloping back window. When you are just about to hit the window, throttle up hard and you will do a jump off the window, slide along the roof of the car, then take off and keep flying :)
(I'd guess you'd call it a 50/50?)
I have done this actually on purpose a few times after stumbling across it (narrow miss) so it IS possible! What can YOU grind? :cool:

Sam

[Andy Magoffin]

Come on, somebody give us a tailslide. Frontside.

[Koichi Tanaka]

I changed into the IR system in order to smooth control of a twin motor.
The rudder and the throttle became proportionality control.
The throttle and the rudder were mixed by the PIC program.
The test flight was performed on the cloudy outdoors.
It was able to control very smoothly by IR.

Koichi

[micro_builder]

looks good Koichi, what is your AUW?

nick

[Koichi Tanaka]

AUW is 16.8g.
IR Rx is 0.45g.

Koichi

[Franck]

I have both mono and biplane for the kids. Bought myself another bipe for conversion. I have build a new plane 40cm span (6mm depron) and 23 cm length. (Ill post a picture later, most of internetservers in Holland are down so it looks...)

Auw is 24 grams (didnt spare on glue). Flies ok, plenty of power. Bit of difficulty stearing, the motors seem too close together on this plane. Another thing is that the plane goes too fast ! All the thrust is (due to lower drag of the wing) converted into speed. That leaves only a asmall amout for diffetrential thrust and thereby stearing ....but thats my guess.

Ill build a new plane, this time plank style, thicker airfoil, more drag, slower speed, and hopefully better cornering :)

Any thoughts ?

Best regards,

Franck

[Franck]

Replacement model 1, and a new experiment plank model 2 (7 grams)

http://artsnoob.herejezus.nl/IMG_1470.jpg

http://artsnoob.herejezus.nl/IMG_1527.JPG

[epilot]

Nice models Franck. I agree that you need to space the motors further apart and perhaps angle them outwards. Perhaps try and use different rudder sizes to see what works best. Yours might be too big.

Michael

[Franck]

Thanks Micheal,

Ive been doing some investigation on the transmitter as well.

I use NiMh cells. The PCB shows some interesting things. First the PCB tells me that it should work at 9V. With 6 NiMH that will be 7,8 V. (measured and ok) Half way on the battery holder there a tap off to a point on the PCB that shows 4.5V (with NiMH's 3,75V). The halfway tap is used as reference Voltage or so, it only drags 4,7 mAh with transmitter on. (charging works with tap disconnected.

The PCB also shows points with 49 / 40 and 27MHz

Voltage on wires to charge airplane lipo shows 5V loaded (unloaded 6V)

Now ive been thinking to add another cell NiMH to make the Vcc back to (7*1.3V=9,1V) but with a tap half way that wont work with 7 cells. Maybe switch to 8 cells ? ( 8*1.3=10.2V) or make a zener do the work. Dunno yet but the range of the TX on 7 NiMH's is worse than with alkanlines.

The lipo gets charged to approx 4.0V with 7 NiMH's. With a Vcc of 9Volts the lipo gets charged to 4.2V. Useing 8 cells is not A good idea I guess :eek:

Best regards,

Franck

[epilot]

You could rewire the TX so it taps 4 cells instead of 3. That would increase the voltage to the TX to 4.8 volts. The TX should be fine as long as you stay below 5 volts. Does it still charge ok with 6 nimhs but with longer charge times?

Michael

[Franck]

Could be done, but rewiring to 4 cells makes 4*1.3V=5.1

Ive measured the current draw on the halfway tap. Charging works with the tap disconnected, so it seems it is only used for the transmitting circuit. It only draws 4.7mAh so making a referencevoltage with a 4.5V zener should be ok (I guess :o )

On 6 cells NiMH the chargetimes are the same (only 4.0V on the lipo cell) , but range of the TX drops significantly.

Question is, what if i change to 8 cells...10.2V tap on 5.1V would it destroy the TX or the lipo ? I have a spare TX...........yellow, plane flew on roof..goner...

Im about to try :D :D !

PS might try using two diodes to make a 0.6V drop. One in Vcc and one on the tap. Vcc would go to (first try 10.2-0.6=9.4V and Tap goes to 5.1-0.6=4.5) Check lipo voltage on charge (may not exceed 4.25V) then maybe remove diode on tap.

[epilot]

I seriously doubt the TX would fry at 5,1 volts but it could be an expensive lesson to learn ;)

[Franck]

http://artsnoob.herejezus.nl/IMG_1530.jpg

[Franck]

http://artsnoob.herejezus.nl/IMG_1537.JPG

AUW 16 grams or so. Need to fix the RX and battery yet.

[Franck]

Ended up with 19 grams AUW. Gonna try flying it tonight. Ill try to shoot some video.

http://artsnoob.herejezus.nl/interpolis.jpg

[melios]

Hi all
appologies if this post shouldn't be here.

I took the X-twin appart after noticing a tendency to turn always to the same side despite trim and ruder adjustment. It also wouldn't climb. I noticed one of the motors was spinning a lot slower. Opened the motor and found one of the brushes was half gone :mad: . It also had a dead spot, sometimes it would require the prop to be hand moved to start spining.

This plane doesn't have that much flying time, was the motor deffective or is it normal to last so litle time? I am in Brussels, does anybody know if I have any chance of buying these motors?
Also I have to built a new tail and want to use the same material (depron?) but the model shops here only have depron 3mm thick and they say they can't have 1mm. Does anybody know where can I get this?

I took some pics of the motor, the orange arrow on the last pic shows the deffective brush.

[Franck]

Havent had this problem yet, ask around on this forum for replacement, shouldnt be too hard or expensive.

Update on flying the plank : excellent flying. It might have been a lucky shot but smooth is the word. even my OFB dropped his TX and flew with it the whole evening, ear to ear grin :D . Ill get some video asap.

[epilot]

Melios, sounds like you were unlucky and got a bad motor. PM me your address and I will send you a replacement motor. I have a couple spare.

Franck, congrats on the model. Look forward to seeing the video.

Michael

[Franck]

YEah tnx. Quite happy with the results. For the first time i was able to fly around no hassle. I Have both mono and bi-plane for the kids so i guess I have something to compare with. The fun for me is that estimated guesses on dehideral, Cg and up throw on the elevons where right on the spot...yeah ! :D :D :D I love it when a plan comes together !


Turn radius, throttle (up/down) control just right ! My OFB went totally weard. that with the fact that i accidently mounted the motors te wrong way..ie, left is right, right is left. Will fix that tomorrow.

I'll post more info on building and video asap (tonight my cam went dead...empty lipo's :mad: )

[epilot]

For anyone needing new motors I think the Didel 6 ohm 6mm pagers will be a suitable replacement. They are a bit higher resistance than the original motors but this might be an advantage since flying often seems to take place at lowest throttle setting. Don't lose the props - I have not seen replacements available anywhere.

Michael

[mharms]

Franck,

I like your plank/wing model. It is elegantly simple. What's the wingspan and how far apart are your motors? I made a similar model, but it used a (large) prop in front. It was not easy to fly. I am contemplating converting it to a dual pusher design (but I may have to add a "nose" in front, as you did, to achieve a proper CG). Are you flying indoors or outdoors?

I look forward to the video too.

Mark

[Franck]

MArk,

Indeed simple it is. The x-wing plank is a scaled down version of my "ultimate planck".

I will update on size, weight and how to. Building the x-wing planck is sooo simple. As for now i've been flying this little 18 grams one outdoors at minimum wind conditions for an hour or so (mostly my OFB)

Finding proper CG is alway a problem with these relatively straight planks as well as elevon deflection. (Btw; when is a plank a delta?). But, build and designed rigged properly, planks are fabulous flyers, with minimum of weight (no tail/boom/fuse etc).

Best regards,

Franck

[Franck]

Movie shot just an hour ago. A little bit of wind makes the wing a bit wobbly in corners.

http://artsnoob.herejezus.nl/MVI_1544.AVI

[epilot]

Great video. I look forward to more info on building "little planks". You should name this one "X-plank"

Michael

[RolfPW]

Hi,
have successfully added an actuator mod to the X-Twin.

some details:
magnets: 3 x 3X1mm neodym N48 (have used one as a centering magnet)

coil: 250 turns, 57ohm

deflection: +/- 40 degrees :confused: (must be reduced)

wirering: as the motors are driven by PNP-transistors :D , i simply connected the actuator to both positive motor terminals.

CG: moved the lipo a bit forward

Conclusion: Turns are sharp. Due to the wrong deflection angels, it sometimes spirals down a bit, but spiraling stops, if i release the rudder for a short time.

Rolf

[Franck]

Now thats cool ! Gonna try that for sure. Did you wind the coil yourself ? Ive been thinking of replacing the transistors by fets with a lower Rds "on". Dunno if that makes sense though.

As far as modding the TX and RX antenna. Ive place two extra cells NiMH on the transmitter. It seems to work fine this way. Checked lipo voltage as it is affected bij Vcc (wich is now 10.2V) Charging turns off at 4.22V (pew thats just within margin :D )

I doubled the length of the reciever antenna to 35 cm. Both mods make the range enough by far. I have control over the plane as far as i can see it. 70/80 meters i guess.

[edit] We did an acurate measurement. With 8 cells, tuned TX coil and 35cm antenna the range of my setup is 160 meters, 1m above ground... :eek: ..hellow....:eek:


http://artsnoob.herejezus.nl/IMG_1550.JPG

http://artsnoob.herejezus.nl/IMG_1551.JPG

[Franck]

Rolf can you give more info on how you build the actuator ? (or maybe point to a link on how to ? ) This micro stuff in kinda new for me :confused:
An actuator will make my previous model turn better indeed. (time for a rebuild)

Offtopic: I almost forgot what the best thing about this cheap RC stuff is.
Check him out, almost 4 years old and (almost :D ) flying like his dad does.....

http://artsnoob.herejezus.nl/superheld mees.jpg

[Hotflyer]

what would happen if one were to hook an actuator (or micro servo) to the motor terminal on one side and build a micro with propo throttle and (with servo) rudder? Probably need a certain kind of current? Would resistors help? Philosophising on issues one does not understand is fun! :p

[RolfPW]

Nice "X-plank"-pilot :)
I use wire from wall timers, they are very cheap (1.85 euro for countless coils).
Winding a coil:
Take a plastic straw, find the end of the thin wire, fix it at one end of the straw and wind 200..500 turns as close as possible around the straw at the other end. From time to time fix the coil with a little bit CA. As the wire is extremly thin, we must strengthen it a bit. Ending up with two coil wires ends around 30cm each, glue both ends back at the coil, twist it a bit, glue the ends of the loop at the same position, twist it a bit and do it again and again.. . .
Rolf

[Franck]

Tnx Rolf.

Got the wire and magnets, will try to experiment some coming days.
Did some searching on this forum too, should be ok.

Cherio !

Franck

[micro_builder]

taking a que from Francks X-Plank, i decided to give my micro stryker a 2nd shot. the first one was made out of foam dinner plates and was too flexy. plus, i was using the BR's PCB and 7mm motors so the weight was just too much (not to mention i really didnt know what i was doing). this new version uses 1/16th and 1/32 balsa and of course the x-twins electronics.

the bare weight of the frame is 4 grams. it could be lighter, but i didnt take too much time in sanding anything but the leading edge of the wing. also could've been lighter if i hadnt made the "cockpit" but it just wouldnt look the same if i hadnt. i got a final AUW of 15g.

i'm still tweaking it here and there, but it does fly. there's no reflex or anything in the fuse, but i cut out the elevons and gave them a few degrees of deflection. the motors are a little close together than what the stock planes have, but it seemed to turn alright. the first couple flights seemed very slow, which surprised me, but i then realized that the lipo was getting pretty low and eventually the LVC kicked in, so i'm waiting for a fresh charge at the moment. i'd like to give this plane an upgrade to 7mm SS motors if things go as planned.

here's a couple pictures.

by the way, Franck, love the plane, and its always really nice to see the younger kids getting into it. and Rolf, i'm glad someone finally managed to get an actuator working with the PCB, might make those turns a little sharper.

nick

[CAFplanekid]

Rolf, I understand everything up untill 'Ending up with two coil wires ends around...' Are you talking about after the coil is made or what? Thanks, once I can find one of these planes I am going to start building stuff. I have alot of tiny little magnets already.

Jonathan

[RolfPW]

<Are you talking about after the coil is made>
yepp

[anestho]

Rolf, so let me get this straight. You added the actuator coil to the plane, what about the 2 motors? Did you leave both of them there or did you remove one of them and move one into the center? Is the actuator proportional?

Would winding a coil with more resistance help reduce the deflection (less current going through)?

[RolfPW]

<"..Did you leave both of them there..">
I only added the actuator.

<"Would winding a coil with more resistance help reduce the deflection (less current going through)?">
That will be the solution.

:rolleyes: Hmm, only an idea: power a single motor from both PNP's decoupled by two shottky's and use differential thrust for rudder.

Gruss Rolf

[epilot]

If the coil is too powerful, add a SMD resistor in series. It will be lighter than using more winds.

Michael

[Franck]

Mechanical restriction of deflection is also an option ? About the scottky's...hmm, you'll lose 0.6 Volt that way but can still use both motors parallel where diodes come together. Hmmm thats worth some experimenting.

First i have to make a working actuator :)

[RolfPW]

Selected shottky's have a voltage drop below 200mV (found some with 187 mV :) )

[epilot]

Rolf, could you come up with a schematic that shows the conversion?

Michael

[RolfPW]

Hi,
The first is the working actuator mod and the second is only an idea. Please comment it.
Rolf

[anestho]

I think that would work with the diodes. I think Epilot mentioned earlier than 1 pager will have plenty of thrust on this model.

[epilot]

No, I didn't say that. It *might* be powerful enough if you lighten the model as much as possible. Much better to use a 7mm pager or an M-20. Not sure how much current the RX can pass though.

The most annoying thing about this model is that it will not turn with motors off. If the single motor/prop will allow cruise at half throttle it will be possible to throttle back and descent while still having control of the model with the rudder - provided the modification Rolf suggested works. I am currently not able to test it.

Michael

[Franck]

Ill try some mods tonight, someone wants to try my "Howto X-Planck" guide for review?

Regards,

Franck

[epilot]

The "Franckenplanck" :D

[Franck]

ok,

0.9 version of the "How to make a X-Planck". Comments highly appreciated !
Use right mousebutton and save as to download the file.

http://artsnoob.herejezus.nl/X_Planck11.pdf

[edit: uploaded 1.1 version of document]

Best regards,

Franck

Rolf, I think it will work with the diodes. Question is, if you want to use one motor you have double te current available. You might replace he two motor by one (bigger one...with a bigger prop.) What motor should be used ?

[mharms]

LOL!
Good one, Michael.

Franck, Just saw the X-Planck video. Very nice, especially for such a small plank/wing/delta. Oh, I see you just posted the "How to...". Thanks.

Mark

[mharms]

Franck,
I'm having trouble opening your file. What program opens a ".rar" file type?

Mark

[Franck]

Sorry Mark :o

Its just another compression program. I changed the file and the link in previous post to .zip.

Regards,

Franck

[Graham Stabler]

are you sure you actually need the diodes, I am not too hot with transistors but I am not sure there would be a problem without them.

[RolfPW]

I think the diodes are a must. If one or both PNP delivers current, the motor has to do his job. On the other hand the actuator has to be quiet, if no or both PNP are active. I have to sleep a night over that idea :confused: .

Having the innards of a slaughtered X-twin laying around, it may be usefull for someone if i supply some data:
one motor with stock wires: 1.50 gram (4.7 ohms)
one prop statically balanced: 0.22 gram
lipoly with stock wires: 3.73 gram
modified RX (no wires, removed input diode, charging connector and switch, replaced electrolyt cap by a SMD type, no antenna): 0.90 gram

ciao Rolf
PS. Franck, thanks for your "How to make a X-Planck".

[Franck]

No problem,

Rolf, too bad I ran out of time tonight, couldnt get to inspecting the RX board myself. About the input diode, why did you remove it (is it for protection against reversed polarity ?)

I found a site www.bitmod.de and they show how to replace the standard NPN transistors by FET's (lower RDs) and so probably more oomph to the motors.

There's a link also on how to make a 3 step (L/R/N) stearing proportional (clever done).That might be usefull. Not for the motors, but for the actuator! Dunno if that would work though. The problem is that the TX sends data to the RX about 3 or 4 times a second, so output is not continous send to RX (pulsed proportional! :D )

Did you remove one propellor, how? (pulling I guess :D ) Ive been thinking on switching to pull setup instead of pusher. It would make CG setup easyer on the planck (no ugly nose and a couple of grams saved !)

Oh btw; Ive changed the "howto" to PDF format.

[Pjotrrr]

Pdf doet het niet / doesn't work.... :(
I want my Franckenplank....... ;)

Peter

[Franck]

He Peter!,

Sorry, I forgot the "c" in the URL......whats in a name :D (thanks again mum and dad)

Try again !

[Franck]

It seems that the TX has "factory off" (very) limited output (tnx to FBK for the hint) . Relatively simple to correct. Just found out how to maximize HF output without expensive HF equipment. Will post data tomorrow.

Gotta go ZzZz !

[DENY]

Thank you for Mr. Franck "How to make a X-Planck" ..
I also try immediately to production.

I made two X-Twin change airplanes.
The first plane is Miles Gemini made from EPP.
The weight of the airframe is 17.9 grams.
This flies well.

The second plane is a no tail airplane.
The weight of the airframe is made of the styrene foam by 11 grams.
It relates however about the center of gravity position or it doesn't fly still
well.

I am Japanese.
The contribution is the first time.
I am not good at English.
My best regards.

[RolfPW]

Franck, i removed the diode because i want use my charger. The diode prevents voltage measurement and adds an offset of around 600mV. As i'll add connectors to the board and the lipo, there as no need for a switch. After removing all the stuff, a 0.9 gram RX is not bad, i think. Will use the equipment on my next project (cootie, X-Planck or ... :) ).

Rolf

PS. Michael the resistor works well.

[epilot]

DENY, welcome on board. Your English is perfectly understandable and better than my Japanese (I know 3 words) :)

I really like your Miles Gemini. Can you post a video perhaps?

Best regards

Michael

[DENY]

Thank you Michael.

The video of Miles Gemini is here.
http://www.jopp-in.net/boss/gemini.WMV
This is the one of the first test flight.
It is a test flight while constructing it.
Because the place is a parking lot, the high degree cannot be taken because it is narrow.
Afterwards
The motor was turned internally and improved because the turn was bad.
And, to fly well, it has been improved.
The length of the main wing is 38 centimeters. This might have been a little too large.

Toshiaki

[epilot]

Filming and flying at the same time! COOL!! :D
Looks like it flies well.

Michael

[Franck]

Thanx deny. Nice video, like the slowlfy.

Two questions :
you did remove the propellors and turned them around to make them pull ? (reversing the motor is not enough, you need to turn the props as well)
Was the flight with flaps down ?

In de video it looks as the plane had its centre of gravity a bit too far back.

Keep em posted !

At a club evening tonight we converted another X-Wing bipe :)

http://artsnoob.herejezus.nl/planck_hans.JPG

[Franck]

For the daredevils among us, here a KISS idea to finetune your TX. I have four TX's now and found out that all 4 have different output. :confused:

Optimizing output on the meter is done by trimming the adjustable coil next to the HF-transistor on the TX-pcb. Remove locking wax from coil and use an plastic or wood screwdriver for max output on the meter. The coil of the meter does affect tuning the tx a bit. Still my TX with tuned output ánd 35cm RX antenna has approx 80+ meters of range. :D :D

Ever tried to control a 25cm/20 gram airplane 50 meters away ? :eek:

http://artsnoob.herejezus.nl/veldsterkte.JPG

http://artsnoob.herejezus.nl/veldsterkte1.JPG

[anestho]

Hi, both diodes are the same? What gauge wire is it? Or does it not matter. What voltages are you expecting (range). thanks.

[DENY]

Hi, Franck.

I asked the senior in Japan.
Mr. Koichi Tanaka taught.
http://blog.goo.ne.jp/toko0131/e/de827c514c79b384797382a9e3f617a3
Please look by the translation page.
It is a method of removing the weight of the vibrating motor.
The propeller was removed by this method.

As for the flap, it is straight.
Yes
The center of gravity position is a back.
The problem is brought up to the turn when bringing it ahead.
This is a phenomenon that can be seen even with original X-Twin.

Turn well. The vertical motion in the nose is not repeated.
Coexisting is difficult.

[Franck]

Hi, both diodes are the same? What gauge wire is it? Or does it not matter. What voltages are you expecting (range). thanks.

Both diodes are the same, and taken of a videocard board (theyre bog standard diodes) Size of wire does not matter, i used 0.3mm.

Absolute output voltages cant really be measured this way, you just adjust the coil for maximum output on the meter. Range, not measured yet exactly but it in the 80 meter range.

Thanks for the link deny :D

[mharms]

Franck,
Thanks for posting your instructions. Very nicely done. I have not seen the X-twin (Aeroace) around here yet. In the meantime, I will "borrow" your wing design to play with. It seems to have good flying characteristics. If I use elevons and a single pusher prop instead of differential thrust, I wonder if it will be more difficult to fly. The X-twin props counter-rotate, right? Do you have any close-up, front view pictures of the X-twin props?

The photo of the red and green X-Plancks (your avitar now, I see) is great. They look like flying pieces of candy.

Deny,
Welcome to RC Groups. Good luck with your planes. I am building a small tail-less plane similar to yours, but my design has the wingtips bent downward slightly (making a bit of a "gull-wing shape). Yesterday, I flew it outdoors as a glider and it was surprisingly stable without any vertical fins at all. I hope you are successful with your tail-less model.

Mark

[anestho]

Franck, you have 1 capacitor in your diagram, but I can see 2 in your picture - an electrolytic 100 uf 35 V and a ceramic (unknown value). Can you please correct the diagram?

[Franck]

Just follow the diagram and you'll be ok. Remember, capacity does'nt really matter.

I will upload a new X-Planck building document v. 1.1 (Plz. follow previous link a couple of posts up this thread.) Last night I correct the size of TE bottom sheet, added revision history, 3 picture pages and templates for ribs.

Best regards.

[Franck]

....If I use elevons and a single pusher prop instead of differential thrust, I wonder if it will be more difficult to fly.

Probably better :D

The X-twin props counter-rotate, right? Do you have any close-up, front view pictures of the X-twin props?

Ive seen pictures of rolf few pages back , are they detailed enough?

....They look like flying pieces of candy. :D

Best regards.

[mharms]

Franck,

I'm doing experiments with cutting-down props and want to try various shapes, so that is why I asked about a close up of the prop. Rolf's picture gives me an idea, so no need for you to take more photos.

In the past, I found that my small, tail-less modes (all used elevons) were pretty sensitive to control input -- pitch sensitive in particular. It appeared to me that when the reflexed portion of the airfoil was changed (by elevon position), the response of the plane was non-linear and asymetrical (more sensitive to downward deflection of the elevon than to upward deflection). If I had a TX capable of exponential, or variable rates (I guess that's the term), my experiences might have been different. I was wondering if the differential thrust setup gets around some of these issues. I'll post what I find out.

Mark

[Franck]

Ok.

Ive been flying and building dozens of planks for a year of three now, and I agree largely on your findings. Never found that to be a problem though.
A plank just flies different that conventional airplanes, no harder, just different.

[Franck]

Switching channels is possible with one transmitter!

Yesterday me and my OFB Hans (who hase some x-twins as well and build the red Planck in my avatar) discussed that it must be possible to switch channels on every transimitter. Why ? Well, we figured that it would be too expensive to build 3 different PCB's one for every channel.

I just spoke him and he found out where on the PCB the channel selection is made. See picture. There are 2 points (marked B and C) on the PCB wich, depending on channel configuration are bridged or not.

A bridge on C point is channel C, Bridge on B is B (duh) and no bridge at all is channel A.

Now, the same thing should be possible on the RX too, have too check this too. Maybe someone with a sharp look can do this check on the RX ?

Cherio !

Franck

Btw: we double checked the effect of mistuning caused by the construction of the fieldstrength meter. We found out that the effect is minimal.(the coil acts as a serious load on the TX)

B- channel
http://artsnoob.herejezus.nl/abc.JPG

A-channel
http://artsnoob.herejezus.nl/cba.JPG

C-channel
http://artsnoob.herejezus.nl/bca.JPG

[RolfPW]

It looks like a jumper :D :
Rolf