Official Skynetic Bison XT STOL Discussion Thread

[2much2do]

53 is way forward unfortuantely, so some of the preceding posts and videos. Although im not sure what your setuo is, im getting about 75 mm with a 4000mah 6s at the very back of thr lower tray.

[skiervh]

Curious as to where some of you mount your battery in relation to CG. Manual says cg is 57mm aft of leading edge. If I center my battery on that and mount on the lower level of the cockpit, this seems to render those stock battery straps useless as they are too far forward. Are some of you mounting on the upper level of the cockpit to match cg that far back?

[Atrix]

Well, I did this and it was crazy successful in terms of tightening up ground steering authority. I was able to drive the Bison like an RC car around my small front yard including laps around a tree. I have no idea how risky this is for the rudder servo. Perhaps I should put a servo saver horn on it.

[Starck Mad]

Well...that was it. My Bison turns well either way now...on the Geo textile or on grass. So...at least for mine...turns out nothing was wrong with my tail wheel springs. I'd like to think moving the control horn made the difference, but to be truthful I think it was as simple as doing something we all have to do to maintain any model...oil it where it needs it. I have video showing the results. We will post our update video first of the week with this information as well as the corresponding footage among other findings and footage flying it like we haven't before... performance on 6s AND 4s. I hope this fixes the tail wheel issue for everybody else as well...doesn't get much easier than that!

[Starck Mad]

I noticed this as well. Where the rod bends and goes through the nut....on the inside part of that 90 degree bend is where there's a lot of friction, keeping the rod from rotating more freely. I'm still unsure how to remedy this.

Actually on mine the friction was because of the control horn on the top of the assembly. When i raised this up just a hair...and oiled everything...free and easy.

[skiervh]

So this is interesting...In was just about to do the mod on my tail wheel and I thought of something, and then noticed something else. I thought about twisting the springs a half turn on one end when hooking them up instead of hooking them up straight in line. This added some tension. While I was messing with it I noticed for the first time...as this was the first time I moved the tail wheel right and left by hand...that there was a great amount of friction and it was a bit hard to move. It was also harder to move to the left than the right. Hmm. So I noticed the horn was tight down on the assembly and there was enough flat spot on the tail wheel wire for the grub screw to raise it up a bit and get it off there where it was rubbing. I did that and put 3 drops of hobby oil down the channel the wire moves in and the combination of all this has resulted in having more tail wheel throw than I've had yet...and at least on the bench it seems like more than enough. Taking it flying this afternoon...we will see. And so will all of you...update video coming first of the week.

Man if that turns out to be all it was for mine I'm gonna feel like a dope for not checking that way before...

I noticed this as well. Where the rod bends and goes through the nut....on the inside part of that 90 degree bend is where there's a lot of friction, keeping the rod from rotating more freely. I'm still unsure how to remedy this.

[Starck Mad]

So this is interesting...In was just about to do the mod on my tail wheel and I thought of something, and then noticed something else. I thought about twisting the springs a half turn on one end when hooking them up instead of hooking them up straight in line. This added some tension. While I was messing with it I noticed for the first time...as this was the first time I moved the tail wheel right and left by hand...that there was a great amount of friction and it was a bit hard to move. It was also harder to move to the left than the right. Hmm. So I noticed the horn was tight down on the assembly and there was enough flat spot on the tail wheel wire for the grub screw to raise it up a bit and get it off there where it was rubbing. I did that and put 3 drops of hobby oil down the channel the wire moves in and the combination of all this has resulted in having more tail wheel throw than I've had yet...and at least on the bench it seems like more than enough. Taking it flying this afternoon...we will see. And so will all of you...update video coming first of the week.

Man if that turns out to be all it was for mine I'm gonna feel like a dope for not checking that way before...

[2much2do]

witch prop is the 6S
bp

15x8

[wperry38]

witch prop is the 6S
bp

[2much2do]

For those keeping score, the light controller is scary hot on a 6s Pack, (I know we knew this but I'm adding too it so that motion will maybe see and fix this for us).

That being said, I ran 6V from a cheapo hobbyking BEC I had in my stash and the light work great, without any issues of heating on that board. So that's the easy answer even if it should not be the case.

I also split out both the ailerons and flaps so that I can precisely use individual channels, I'm keen to try aileron droops (camber), since that should work if the slats are working, and maybe slow down controllable flight.

[2much2do]

Maiden today + 3. Getting used to how it flies. Great for doing touch and gos. As previously been reported you have to keep power on it but i like the way it flies. Got the tailwheel to mostly turn left using tighter springs and 125% rudder but i think i will try a closer hole for more travel. Has anyone come up with any ideas for the red hot light controller? I originally had it switching on and off on the gear channel but that stopped working (fried?) Now they're on all the time. Using 6s 5000 at 70 mm seems like a sweet cg. Landing with about 45-50% after 8 mins.

I know the LEDs will run off of 5V, but has anyone tested to see of the controller will? If that is that case, then putting it after a higher current BEC might be a good option.

[Capt G]

Maiden today + 3. Getting used to how it flies. Great for doing touch and gos. As previously been reported you have to keep power on it but i like the way it flies. Got the tailwheel to mostly turn left using tighter springs and 125% rudder but i think i will try a closer hole for more travel. Has anyone come up with any ideas for the red hot light controller? I originally had it switching on and off on the gear channel but that stopped working (fried?) Now they're on all the time. Using 6s 5000 at 70 mm seems like a sweet cg. Landing with about 45-50% after 8 mins.

[2much2do]

2much2do I'm going with your idea and making the stinger longer. We will post an update vid first of the week and I'll show how that works among other things.

Rapid-fire proof of concept, I just moved the tail wheel pass-through back s bit with a small bit of carbon plate, and attached that through the original hole with a 10/32 machine screw.

I should note that I had tighter springs on it already, and that didn't change much as far as wheel travel. This actually seems to make it much more consistent at least.

https://youtu.be/aLG2F7jVb9Q

[Starck Mad]

2much2do I'm going with your idea and making the stinger longer. We will post an update vid first of the week and I'll show how that works among other things.

[Starck Mad]

Now where does the black and white lead connect from the light controller? I hocked it to the gear channel, thinking it may turn lights on or off, since the is no wire in th center power plug. ?? It didn’t do anything that I noticed. Will mess with it later. Still fixing flat tires, got one ok still a leak in the other.

Mine is in the gear channel

[Denc23@comcast.net]

Now where does the black and white lead connect from the light controller? I hocked it to the gear channel, thinking it may turn lights on or off, since the is no wire in th center power plug. ?? It didn’t do anything that I noticed. Will mess with it later. Still fixing flat tires, got one ok still a leak in the other.

[Starck Mad]

You know the best answer is probably actually to make a longer tailwheel stinger. That would give the springs from the rudder a better pull angle. I might make a carbon one since I can't finish the plane.

Now that idea I like a lot. Easy to do too.

[2much2do]

You know the best answer is probably actually to make a longer tailwheel stinger. That would give the springs from the rudder a better pull angle. I might make a carbon one since I can't finish the plane.

[Starck Mad]

Very weak tailwheel springs. I can hardly turn one way or the other. Tried shortening the springs to apply more tension, I may have attached them wrong or cut them too short...really not sure because I still can't get the tail wheel to turn much at all. Any suggestions or alternatives?

2much2do's suggestion may work...I'm going to use stronger springs, but to be honest for my last several flights this week I've been just lifting the tail with down elevator and some power and getting the tail around tightly that way. It's pretty easy to do with this plane because of the high angle of attack with the tall main gear. The tail doesn't have to come up much and with full rudder she comes on around...looks like a real bush pilots plane when you do it too! I realize thats a technique fix not a mechanical fix, but it's fun...

[2much2do]

Very weak tailwheel springs. I can hardly turn one way or the other. Tried shortening the springs to apply more tension, I may have attached them wrong or cut them too short...really not sure because I still can't get the tail wheel to turn much at all. Any suggestions or alternatives?

Im fairly certain looking closely at it with smaller springs, that that answer will be to drill new holes for the srpings closer to the center of the wheel pivot.