Nice video Aircontrol and Kwill.Air..... yours seems very responsive to the throttle differential. Especially in that knife edge pass

Originally Posted by Kwilletts

I am having an electronics problem, perhaps someone can lend a helping hand.
First allow me to describe the problem, and then I will explain my setup. I am having a motor issue where the rpm of one motor seems to surge... I have noticed this and my last airframe of the twins.

If you listen on this video you will hear the motors surging. It is a continual thing rpm's drop and the rise again and again. This is on one motor only...

http://m.youtube.com/watch?v=ymvjq__Hg-k



Throttles come out of the throttle channel into a y cable to the two HK 10A ESC's. I have lifted the power wire from one of the esc cables so to not overload the receiver. No V-tail for differential thrust on this so far. The one thing that I have noticed is that this happens when I run my 20c 800 mah 3s through it. If I run with a 15c it doesn't do it. Anyone have any ideas?

Have you figured it out? My guess is that the esc is going into "over amp protection" mode. You may be right at the max amp rating for the esc. A 20C battery will give up more amps, under load, than a 15C. For example the 15C may max out at 9.5 amps but the 20C may deliver 10.5 amps and the esc will go into overload protection.

Originally Posted by aircontrol

This is my first Twin Cargo Plane, and its a lot a fun! Thanks foam and tape for the great design, and thanks larryross for all your hard work on the plans.
Of course I had to make a few changes of my own. My twin is made of EPP, with a 48" ws (85%) of the original.

Here are the Mix's I used to get the rudder and throttle differential on a DX7s.
Note: I saved the gear port for the back door and used the AXI port for the left motor.
Mix 1
THR > AXI
Rate 100%
100%
Mix 2
RUD > THR
Rate 60%
60%
Mix 3
RUD > AXI
Rate - 60%
- 60%

I was able to brave the wind and cold today for some video. Enjoy!!!
https://vimeo.com/56821679

How is my plane flying? =)

Originally Posted by TMAC4123

How is my plane flying? =)

Flies terrible! You wont like it. So now its MINE! LOL! We will have to get together this week and let you try it out.

John.

anyoen every try a low wing twins?

Originally Posted by nemoskull

anyoen every try a low wing twins?

I've thought about it. I think you would want dihedral.

yeah. i built a glider. but i was wondering if anyone has done it before.
i put a 25% fuse and tail to a 30% wing. buried in the fuse at eht bottom. it real windy here, but i want to a test glide it. dehidral has the wing tips just above mid way up the fuse.

if uncontroled glide goes well, im putting in r415 and twin 7mm with AA props.

but tthat blasted wind has to go first...
i really want one at 35% with a removable wing and retracts.... but i will dream untill that happen.
ar6400T on the way, as well as 4 2G motors. (twin quad?!)

*sigh* been on the ground far too long. bad things happen when i dont fly.

illl post pics if some one wants to see.

edit: if i had the wings removable, i could sneek it into the library!

Originally Posted by nemoskull

anyoen every try a low wing twins?

Hmmm... A little more bashing and visions of "'Old Shakey" are coming to mind.

Ted

That C-124 has some SERIOUS WIng Fillets ! ! !

A N D that tapered wing makes me itchy too

Not to mention Ground clearance for the props.

Still , the basic Twins is so stable that Doing the Low wing Thang may result in FUN !

Originally Posted by urpu36

Have you figured it out? My guess is that the esc is going into "over amp protection" mode. You may be right at the max amp rating for the esc. A 20C battery will give up more amps, under load, than a 15C. For example the 15C may max out at 9.5 amps but the 20C may deliver 10.5 amps and the esc will go into overload protection.

Well, after swapping out the suspect esc, it has cleared the problem. I would agree with your assesment but as this is split over two motors..... The motors will only draw what they need.... I fly these motors on firefly's with an 8X6 on the same controller... no problem. So i dont think that I am over amping the esc. I think that the esc I just think that this esc has an issue. I am going to start an upload to youtube of one of my flights for tonight. The second one I will not post as i landed on the roof of my boss's house. He got a kick out of it. i will put a link up later.

Originally Posted by Kwilletts

Well, after swapping out the suspect esc, it has cleared the problem. I would agree with your assesment but as this is split over two motors..... The motors will only draw what they need.... I fly these motors on firefly's with an 8X6 on the same controller... no problem. So i dont think that I am over amping the esc. I think that the esc I just think that this esc has an issue. I am going to start an upload to youtube of one of my flights for tonight. The second one I will not post as i landed on the roof of my boss's house. He got a kick out of it. i will put a link up later.

Glad you got this sorted out. I'm looking forward to seeing your video. Sorry, did I miss something? Why not post the "roof landing" video?

BG

BG... Well its almost a gig... Slow to upload (sounds like a good excuse) Here is tongiht's video. Weather is supposed to filter in on us over the next few days here. I just got my differential throttles setup tonight after my last flight. Now the plane is at the track, and I am at home... anyway thanks air the mix setup you listed got me there, it can goto the gear Channel on a dx8, you just have to turn the switch off in the switch select. Also have to watch out for rudder trim.... It had me scratching my head for a few mins. Without further ado.... Tonight's footage...

Twins Jan 8.avi (3 min 11 sec)

well after my first twins build and a motor change lol lack of power, then a fatal crash my bad < Bob hooked me up with a new fuselage and it turned out way better
this time of corse have the H tail finished and suspension done ill post picks bty the weekend.

going to try a twin battery setup this time i was running a single 5k 45c 3s im going to see how 2x 3000mah 45c 4s will do my power is coming from two e-flite power 25's and 10x6 props ill have to re weigh last time with the 5k mah battery just a tad over 5lbs flew awesome one of my favorite planes to fly...

Cheers
Scott

ps. thanks Bobs cutout service

Neat LG Tricks !

H stab looks like Skyscraper construction !

I think you will have Rudder authority !
Like enough for Knife edge !

Thanx for comps. Glad to help out.

Bob
Hoosier Cutout Service

yeah the landing gear is sweet put 90 weight oil so there nice and slow if ya come in hard you cant tell butter landings every time... my boss rigged em up turned out pretty sweet.