PDA

View Full Version : Stryker Twin w/ Differential Thrust


Kosh
05-19-2009, 11:13 PM
I was bored with the Stryker after trying everything else under the sun with it but this. A simple V-Tail mixer added to twin motors for differential thrust controlled by the rudder on the TX. I know this has been done before by a few but never seen one on a F-27. There was no special mix on the TX and it was just a plug and play kinda thing so I gave it a try.

A pair of cheap $7 1800kv HC outrunners spinning 6x4 props provide plenty of power while keeping the amps down. A single 25C 2200 3 cell was enough to provide juice for 10 minutes of flight and only come down slighty warm. Other than adding a pair of motor mount sticks to the fuse no mods were made to the rest of the plane.

Kosh


sNRBgn0nvZU

Larry3215
05-19-2009, 11:42 PM
Thats pretty darn cool Kosh! Insane spin!

Exactly how did you wire in the mixer? Im starting a 5 motor project and some differential thrust would add another whole dimention. 4 of the motors would be used and I dont have nearly enough mixes in the tx to do it that way.

Larry3215
05-19-2009, 11:44 PM
Another question - does only one motor change speed or does one speed up while the other slows down and vice versa?

Kosh
05-20-2009, 12:13 AM
I plugged both ESC's into the V-Tail mixer, From the mixer one went to channel 3 for the throttle and the other into channel 4 for rudder. If it doesn't work swap the leads from the mixer into the RX and your good to go.

With a Y cable 2 motors into a mixer channel should be fine to make 4 of your 5 motors work this way. With the throttle turned off you can make each motor spin up by hitting the rudder left or right. The more you move the rudder stick the faster the motor spins on that side.

Throttle is normal until you apply rudder with both motors spinning, Add rudder and one motor stops while the other speeds up depending on how much rudder is applied. Let go of the rudder and both motors act as normal again, I found that the F-27 will knife edge on one motor alone. :D

Hope that helps out, Kosh

Larry3215
05-20-2009, 12:20 AM
Thats perfect!

Thanks!

smokejohnson
05-20-2009, 12:49 AM
That is too cool Kosh :cool:

Nitro Blast
05-20-2009, 01:05 AM
http://images.icanhascheezburger.com/completestore/2008/8/2/werenotworthy128621860874600034.jpg




I'm scrambling to get the stuff to build something like that.
Plug and play. Damn cool Kosh.

Kosh
05-20-2009, 01:40 AM
I've seen planes do this in the past and always wanted to try it myself. I give all the credit to Chellie because when I did a search here she spelled out to make it happen.

I've done most everything you could think of to a Stryker already so this was easy. I tried 7x5 props at first and got much better speed but was heating the battery up so went to the 6x4. While I dont own a wattmeter I know I'm well under 30 amps total for both motors just by the lipo temp alone.

CHELLIE
12-16-2009, 09:03 AM
I still think this is Outrages, Totally cool, I have a stryker foam body here, so I am going to be a copy cat and do what Kosh Did, when i get some time, Gee i still have a bunch of other planes to finish up on :)

Kosh
12-16-2009, 09:44 AM
I've had lots of fun with this plane and last summer it won a "Best Technical Achievement Award" at a fly-in. People were running off the flight line thinking I was out of control and about to crash. :D

Just keep the props to 6" or 7" at most and twins fit fine. I may try another version with motors on the front and back just for the heck of it. You just cant beat the sound of a twin setup.

CHELLIE
12-16-2009, 10:19 AM
Hi Kosh :ws: Long time no hear :ws: I love the sound of that twin stryker its super cool :D I have been telling people about that little 1800kv motor, i love it, i have it in a foamy pusher jet, it hauls buns, 20 amps and 210 watts :eek: its a blast to fly, yea i am pushing that little motor, but it likes it :)


http://www.wattflyer.com/forums/attachment.php?attachmentid=115761&d=1260958759

Kosh
12-16-2009, 10:28 AM
I bought 4 of those little motors and have been abusing the heck out of them for over 2 years now and all are still going strong. I've tested these motors on more planes than I can count and they have never let me down even after major crashes. :o

CHELLIE
12-16-2009, 10:43 AM
I bought 4 of those little motors and have been abusing the heck out of them for over 2 years now and all are still going strong. I've tested these motors on more planes than I can count and they have never let me down even after major crashes. :o

yes they are a very very strong little motor, it has large dia. wires in the motor, maybe thats why it can take so much amps ???? they just work great, cant beat the price too, later i would like to make a p38 with these motors, that will look and sound cool. something like this.

http://images.google.com/imgres?imgurl=http://astro.umsystem.edu/andy/rc/p38foamy/fly/p38foamy_20070330_01_640.jpg&imgrefurl=http://astro.umsystem.edu/andy/rc/p38foamy/fly/&usg=__IEEMLslXPgKP-yg9zZ_JakKA7_k=&h=480&w=640&sz=72&hl=en&start=1&um=1&tbnid=0Cl3mW5ldP28KM:&tbnh=103&tbnw=137&prev=/images%3Fq%3Drc%2Bp38%2Bfoamy%26ndsp%3D21%26hl%3De n%26sa%3DN%26um%3D1

Kosh
12-16-2009, 11:05 AM
The P-38 would be great with a pair of these and I've found they really come alive with a 7x6 or 7x7 prop for speed. If I'm after more thrust then I use the 8x4 to get the job done.
I really have no idea why these motors don't simple go up in a ball of smoke the way I use them. You could be right about the larger wires but I just don't know.

EpoweredRc
12-16-2009, 07:00 PM
Where do you buy these motors beside hobbycity and hobbyking? anywhere thanks
thinking about one on a 22 inch delta I have . with 3 cell 1300 mah maybe? 5 min flights fine with me

CHELLIE
12-16-2009, 07:17 PM
Where do you buy these motors beside hobbycity and hobbyking? anywhere thanks
thinking about one on a 22 inch delta I have . with 3 cell 1300 mah maybe? 5 min flights fine with me

Hobby King is where I get mine at, I dont know if anyone else sells them, super little motor for the price and a ton of fun too :D Take care and have fun, Chellie

Kosh
12-16-2009, 07:19 PM
Sorry but I know of no other place. http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=5430&Product_Name=AX_2308N_1800kv_Brushless_Micro_Motor

A 800, 1000 or 1300 battery is most often used to power them and I use a 800 lipo on my F-22.

EpoweredRc
12-16-2009, 07:23 PM
Sorry but I know of no other place. http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=5430&Product_Name=AX_2308N_1800kv_Brushless_Micro_Motor

A 800, 1000 or 1300 battery is most often used to power them and I use a 800 lipo on my F-22.

dag nab it lol. um well yeah we got a 1300 i belive it is. I could get a 800 if needed. I knwo the plane will fly with it. I need find my old specs ive flown the plane with a e flight 480 and a 4 cell a123 1100.

got a video fo your F-22?

Kosh
12-16-2009, 07:38 PM
If your plane flew with a 480 and this motor is MUCH lighter then your 1300 pack should be fine.

n9UYaMsQ3WI

EpoweredRc
12-16-2009, 07:59 PM
your just playing in that video lol got one WOT? it looks like it flys nice and slow whats yoru AUW? orginal mine was 14.0 then with A123 and 480 it was 19.17 ounce's

Kosh
12-16-2009, 08:46 PM
The F-22 was designed for combat and not speed. The 24" version came in around 10 ounces and had a top speed of about 55 to 60mph on that setup. Most all flat profile plane just wont hit above 70mph with running into a aerodynamic brick wall.

EpoweredRc
01-26-2010, 05:22 PM
I know this kinda old but what esc's did you use? i got my motor and tryed it with a parkzone esc i couldnt get past half stick w/o the motor trying to stop and run backwards and made a terible noise while doing so, hooked up to my Castle creations esc and it worked fine.

I got a DC-9 its foam kinda ugle but never done anything with it now I am thinking maybe get another of these motors and put on it. maybe a 6x5 prop or has anyone tested with smaller then a 6x4? not sure about ground clearence. dont have the plane with me right now going to go grab it tonight.

Thanks for info. so when you did your flat spins did you cut throttle back to nothing and just applied rudder to make motor run or did you leave throttle one also. as in was just one motor running or was both but one more then other. Again thats a cool video.
wonder if you could do it w/o a mixer I guess not. where did you get the mixer at?

Kosh
01-26-2010, 06:49 PM
I just used cheap HC SS ESC's on mine that worked ok but yours sounded like the timing was set wrong for the motor. If you try a twin like this both motors and ESC's should be the same kind with the wires the same length. I used this ESC http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=6457&Product_Name=Hobbyking_SS_Series_18-20A_ESC

Those 1800kv motors should spin a 5.5x4.5 APC prop but I wouldn't go much smaller than that.

To get the plane into a flat spin I went straight up and cut the power causing it to stall. As soon as it stalls just move the rudder all the way to the left or right giving only that one motor full power and the spin starts. To get out of the spin move the rudder the other way for a second and let of it to resume normal flight and throttle use. Only 1 motor at a time works when the Vtail mixer is activated, Both work as normal until you pull on the rudder. I used this Vtail mixer but any should work http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=6321

I'm not sure you will get even close the the same results with your plane and that's why I picked a delta pusher for my project.

EpoweredRc
01-26-2010, 10:15 PM
Wow thanks for the info and links, those are cheap enough esc and mixer. well I mostly just want to put the motors on my DC-9 but the flat spins were cool with yours. hum I used a parkzone controller. guess i will try some others we have to see if any others I have will work. thanks for the advice I knew had to be same kind and same wire lenghs and all. its brushed right now I might try it like that to see how I like a twin.