Sbach3D 55 size - Design, Plans & Construction

[TriFlyer3D]

I had a 17X10 APC E on it with two 3600Mah 3 cell batts. I am sure you can use a smaller battery with no problem but the thing floats around with these.
Nice pic Rookie! Thanks! I am playin with som vid right now..

You might want to try a 18X6 or 8 on it and try to improve on the wimpy climb rate I saw in the video.

[Zamfir]

Well I got in 4 flights today on the Sbach 55. All I can say is Wow! What an incredibly fun plane to fly!

Wait till you try the Sb65.

LOL! I can only imagine. Hmm..gonna have to come up with little different power system for that..Don't think I have not been watchin that thread..

Here is some hacked together vid of my hack thumbs flying this very nice bird. (when it gets done uploading) http://www.vimeo.com/9122960

[ryan_m]

Got mine finished up finally. Looks like it will balance up right at 6.25" back, but my packs are on loan to a buddy right now so will have to see. AUW looks to be just under 6lb with a pair of 3s 3300 packs on it. Without batteries it's 4.5lb even.
Neu 1509 1.5Y for power with a 5.2 gearbox spinning a 16x8 prop right now. I tested it with a battery that was not charged up and it showed 1400 watts on the wattmeter, guessing fully charged will be a closer to 1600+. The pull was incredible during the runup... scary even. Probably get the maiden either friday afternoon or saturday morning. Can't wait...

[Zamfir]

I sure hope you can get some vid of that scary powa! I wanna see I wanna see! Yer gonna love this bird!

[ryan_m]

There will definitely be video. Maybe not of the maiden, was hoping to have xraydoc shoot some, but our schedules aren't working out just right. But I will definitely have video of it sometime soon.

[ryan_m]

Holy crap. Flew the Sbach this morning for the first time. Video is encoding now, will post it up soon. Didn't stick it on a wattmeter, but according to the castle data logs it was making 2400 watts. On 6lb... 400 watts/lb! WAAAAYYY too much. Goes vertical like a damn rocket. Got in one 6.5 minute flight and only used about 2300 mah out of the 3700 packs. Probably get around 8-9 minute flights pretty easily.
Was a very very windy day, have no idea if the plane is trimmed at all. I didn't touch any trim buttons, too windy to tell. Same for CG... dropped the nose badly when I let off throttle, but still seemed neutral when inverted. Have to wait for a better day to really tell how it's balancing. Power was absolutely absurd. Had to turn the rates down on full throttle punchouts or it was nearly impossible to keep it straight.
Had some wing rock in a harrier, but again might have been wind.
Second flight I had the elevator pushrod come off (might have forgotten loc-tite...) but managed to use the throttle to ease it down into a swampy/weedy area. Broke the covering in a few places and the uprights where the balsa was routed out for the servo wires. Might need to reinforce those if I build another. Otherwise no significant damage, got lucky. Got her all repaired and ready to fly again tomorrow though. Can't wait to get a few more flights on it and try to get it dialed in a bit better.
And get used to it... the dropping nose was a bit unnerving. I suspect it's just a difference between a Neu and a glow motor, the gearbox seems to slow the prop down very quickly when the throttle comes off. Might need to configure more of an 'idle spin' with it so it doesn't completely stop spinning.
Attached is the castle graph of the 2nd flight. Mostly a lot of low harrier into the wind and one punchout before the failure of the pushrod

[ryan_m]

Video link:
http://www.vimeo.com/9257273

crappy vid... wind, cold, new plane, yada yada yada. need to get better conditions, get the plane dialed in, and used to it, then will get some better video soon hopefully.

[3dRookie]

What wind? Plane looks damned good!

Wing rock? Check your aileron alignment, Ron's 55 that I flew at Ottumwa last year didnt have any,... Zamfir's plane didn't seem to have any either. ( I turned down the sticks when he offered em,... No need to crash the plane on the day of the maiden! )

[TriFlyer3D]

Thanks Ryan, your results with the neu setup seem to confirm my own. Besides the difficulty in trying to control the torque and power, what you refer to as the nose dropping is slightly different than what seemed to me to be happening. What I found was that the plane would not slow down when one backed off on the throttle. In fact the plane seemed to actually speed up. It made walls and waterfalls difficult because when you backed off the throttle and pulled up the plane would zoom up 10 feet. I expect this is due the prop being almost stopped and not creating the drag that comes from the airflow spinning the prop.

I think xraydoc had it right in one of his post where he says around 200 watts per lb is where the planes fly best. That is about my conclusion as well. I try to prop for about 200 to 250 watts per lb depending on what props are available. All the E planes I have fly best at that ratio. The thing about that is what is the use of spending $400 for a neu set up if you are not going to use it to its max, might as well just use a $50 out runner. A 6 lb airplane only needs 1200 watts. 60 amps X 22.2 = 1332. Pretty easy to get that out of an outrunner and 3000Mah 25C batteries as well. Much lighter setup that will fly better and will still give about 7 - 8 min flight times.
Just MHO based on my personal experience and conclusions.

You should not get any wing rock with the Sbach. Check that the ailerons are level or slightly up, also check that the ailerons are not warped any causing the tip to be lower than the root. There should be no gap in the ailerons or at least the gap should be the same in both wings. If not seal them both with some blenderm tape.

[ryan_m]

Got in two more flights on it today in near zero winds. Slid my throttle trim lever up to the top to let the motor keep spinning like a Saito would, prop doesn't stop now when I come down to zero throttle. Much better. No more nose drop. Wing rock was not a problem today. Not quite as stable as a Mojo 60 or Sabre 56 in high alpha, but doesn't rock either. I think what tiny rock I did get was only due to the throttle modulation and that forcing a wing down slightly more than I was used to because of the slightly bigger prop. I don't think it was airframe related at all. Didn't prop down, but the system also didn't seem like 2400 watts today either, seemed maybe closer to 1800-2000. Will have to pull the graph data and see. Wasn't uncontrollable, and really didn't even feel like too much power. Well maybe a little but I didn't mind it at all. For what it's worth I was able to find this motor used and got the motor/gearbox for something like 230-250. Not bad. I do prefer it to an outrunner though. Flew 8 minutes on 3300 mah batteries and still only put back in about 2500 per pack. Very happy with the flight times. Knife edge had no elevator coupling going right to left and no roll coupling. Going left to right I had a tiny bit of roll coupling, no elevator coupling though. Waterfalls were fun and smooth. Managed a few knife edge spins, but had a hard time doing an upright flat spin. Had to back way off the elevator, almost no elevator input required on this plane and then it spun ok. Definitely not Chinn Yak spin happy. Will have to get some more time on the plane and get more used to it, but I'm liking it so far!

[WessCo]

It's amazing, I mentioned this in the e-RazorYak thread and no one picked up on it. Looks like you might could win some vertical drag races with this plane ryan_m!

[nitrofevr]

That NEU sounds awesome!!! That was the first time I have heard one. Great looking plane.


Ryan, Nice Vid. and nice looking bird! I love the wheel squeaking at take off

[jvino]

Holy shit bro, that thing is ballistic!!!

[Zamfir]

Yup..That be some power. Could use that setup on a bigger bird easily!

I can not wait to get some more stick time on mine!

[zpat]

I can only descibe the sound as a turbo Saito with rocket power!

That's neat!

I just wish I could decipher electric talk.

[ryan_m]

That NEU sounds awesome!!! That was the first time I have heard one. Great looking plane.


Ryan, Nice Vid. and nice looking bird! I love the wheel squeaking at take off

Check out this link and you can see xraydoc's Sabre 56 meet an untimely death when it ejects a pack. You can definitely hear the Neu on it too. Angry sounding things they are! I believe his was making around 1800 watts on a 17x8 prop.
http://www.vimeo.com/9279940

On the wheel squeak, yeah it seems when there is no more glow slime to lubricate the axle shafts that the wheel squeak gets a whole lot louder! Maybe I should find an oil can...

[TriFlyer3D]

Excelent flight report ryan, it would be good if more bros would do one so I could get a better idea of what if anything needs to be changed on the next one.

Where did you finally end up with the CG?

[TheGreatBoo]

Triflyer I've started to cover my 55 and noticed that you have some pretty "Sbach" lettering on your Sbachs. I'm planning on cutting "Sbach 55" from monocote and windex it on but don't know the font its supposed to be written in. Do you know the name of the font or do you perhaps have a template on .pdf or .doc format I could ask for?

[TriFlyer3D]

Boo, the letters are hand drawn to match (somewhat) the original Sbach logo. Attached is the logo in pdf format. It is about 10 in wide which is about right for 40 to 60 size. If you need it a larger size or different format let me know. The vinyl on the original was made by ProBroAndy, two sets are cut in two colors and one is offset laid on top of the other to give the 3d or shadow effect.

[TheGreatBoo]

Thanks a million Triflyer!! That's exactly what I was looking for now I just got to find some more cool stuff to cut out for it. You do not happend have a " By Triflyer Designs " logo somewhere