Official Skynetic Bison XT STOL Discussion Thread

[skiervh]

My wings have been pretty tight when installing and removing from the fusalage. On my 7th or 8th time removing wings, noticed some separation here. Easy fix but just something for others to be aware of.

[Atrix]

I have seen that style and actually have a similar set on the way, but I am going for something a little different that would actually glue to the ends of the ailerons and wings to protect the foam if it does make contact with the ground.

[2much2do]

Something like the tip skids Mike Patey puts on all his airplanes?

Just FYI these are for sale all over:

https://www.motionrc.com/products/du-bro-60-9mm-2-40-wing-tip-tail-skid-2-pack-dub992

[Atrix]

Just an update from my weekend exploits with the Bison. We had an event at my local field, and I got some more eyes on the Bison from the crew of experienced pilots. Everyone was a bit flummoxed by the tail wheel and its tendency to not track very well (especially after some rudder input), making take off from the paved runway very tricky. There were a good number of failed take offs and ground loops and unfortunately the ends of my wings are bit beat up as a result. Once we switched to takeoffs in the grass, things improved quite a bit, but I am not entirely sure why, maybe less traction on the rear wheel meant less likely to be taken off course 🤷♂️

In any case, once I could take off with some regularity, I got through about 5 packs without too much trouble. In the air, I am still having to trim rudder, but other than that it was well behaved. I was doing low, slow passes all day with a few rolls and loops tossed in here and there. I have flaps mixed with elevator, but I have to tweak that a bit because I still pitch up on half flaps and pitch down on full flaps. Despite all the interesting challenges, I am still quite happy with the Bison and really enjoying it in the air (less on the ground).

Some things in the works. As you may have seen above, I am working on a springless tailwheel setup. I will report back how that goes this weekend. Also, I am designing 3D printable custom wing/aileron skids to help with my tendency to chew them up on ground loops. I am going to try and have them connect with a joint to help reinforce the foam hinge. I will certainly share them here for anyone interested.

[2much2do]

Did you get this resolved?

I have a tracking number, but nothing in hand yet, I saw you had the same issue, they had me fill out their online trouble ticket, and then attach pictures. You have to keep bugging them to make them move it forward. There was something else they were supposed to do which they still have not done.

[Gilatrout]

My kit came with 2 left wing struts.....they can't be built upside down...wtf

I even tried to flip one by re-tapping the plastic parts, the angles on the plastic do not fit with the bottom of the fuselage.

Did you get this resolved?

[2much2do]

Hmm, I don't completely follow. Slats, in general, are useful (see video), but are the "slats" (spoilers?) on the Bison, in their current actuation form, useful? And if so, for what? Slower flight? Different flight characteristics? Is it just that it's harder to fly and that provide extra challenge for experienced pilots?

Fully closed they are placed well to be slats, they should not be "Opened" so most people are just fixing them in one position and not trying to use them as an actuatable surface.

[Atrix]

So the slats are useful, and people report them working, but don't open them with the actuation as designed.

Hmm, I don't completely follow. Slats, in general, are useful (see video), but are the "slats" (spoilers?) on the Bison, in their current actuation form, useful? And if so, for what? Slower flight? Different flight characteristics? Is it just that it's harder to fly and that provide extra challenge for experienced pilots?

[2much2do]

Is everyone locking out the leading edge slats? Are they not actually useful?

So here is a quick explanation of how slats are supposed to work:
https://www.boldmethod.com/learn-to-...t-lift-device/

The slats on the bison, don't open correctly, effectively the become leading edge spoilers I think, which is a problem.

So the slats are useful, and people report them working, but don't open them with the actuation as designed. You can read a lot more on this design in the RCG threads for the seagull shock cub

Also if you look at the Freewing T-45 that Motion sells, it has slats that at least look like they would work a champ.

[Atrix]

Is everyone locking out the leading edge slats? Are they not actually useful?

I have them disabled, and it is not very clear to me what value they bring. I presume the idea is that they would enable even slower flight than what the flaps allow, but I don't recall anyone saying so explicitly.

Some have said that there is an ability to tune the amount of slats that are activated for a given amount of flap, but, mechanically, I don't know how that would work without a springed linkage to the slats (like nitro rc car throttle linkages). Otherwise in order to have zero slats at zero flaps, there would be a fixed ratio of slats to flaps.

[Warlox]

Is everyone locking out the leading edge slats? Are they not actually useful?

[2much2do]

Couple of videos I saw CG was 75-77mm from forward slats. Think I’ll start at about 70mm. I usually start at 30% of the cord, which should be the thickest part of wing or at the spar on normal wing.
Most all tail daggers have the tail wheel connected directly to the rudder, no springs, so shouldn’t hurt the servo removing the springs hand using straight linkages.??

I, mean, depends on you. You put any shock into the plastic horns on the rudder. So if you always land gentle it would be fine. Im not sure how strong those horns are, if they are strong you will also be fine.

[Denc23@comcast.net]

Couple of videos I saw CG was 75-77mm from forward slats. Think I’ll start at about 70mm. I usually start at 30% of the cord, which should be the thickest part of wing or at the spar on normal wing.
Most all tail daggers have the tail wheel connected directly to the rudder, no springs, so shouldn’t hurt the servo removing the springs hand using straight linkages.??

[2much2do]

Well I'll put it this way. I will never ever buy another Skynetic branded plane right away even if it is one of the unicorns. Even then it is going to have to have amazing reviews for me to order it,

I would agree, Motion had a great reputation as a re-seller but they are kinda failing as a manufacturer in my mind. And my experience was that their customer support regarding their own product is less than stellar.

They tried to make an item that was higher end than they were capable of producing, with features that were beyond the designer's understanding.

This might seem unfair, but the more I think about what they've done the more frustrated with them I become.

[Gilatrout]

I have been holding off on actually writing my review on their website until I had enough parts to actually fly it. It really bums me out the way so many of us are getting a bit hosed on this deal.

Well I'll put it this way. I will never ever buy another Skynetic branded plane right away even if it is one of the unicorns. Even then it is going to have to have amazing reviews for me to order it,

[2much2do]

I have been holding off on actually writing my review on their website until I had enough parts to actually fly it. It really bums me out the way so many of us are getting a bit hosed on this deal.

[Remberin3]

Just got mine today. I noticed that the windows look like they have overspray on them and the very top one looks like someone dropped CA on it. Also there are not enough y harnesses to plug all the lights in. Also the esc was disconnected from the motor, and just laying loose in the battery tray.. Was anyone else's like this or did I get one that was returned by someone.

[Gilatrout]

Well, I had some time to work on Bison, but I too have the backwards strut assembly problem and so until that is resolved it's grounded.


Thanks for the advice on the tail wheel. A little lubrication, and some fiddling it is much better. Still not where I want it, but not a blocker anymore.

Damn this model has been frustrating.

Oh one more thing, check the glue for your flap and aileron control horns. One of mine wasn't glued properly.

[2much2do]

Im barely able to use both strap. I might hunt up a piece of neoprene to put in there to prevent any sliding.

[skiervh]

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.

Actually it says 57, typo on my original post...either way I thought it was too far forward regardless.

So running your battery further back, are you able to get a strap around it or are you just using vecro?