My KFM Flying Wing

[basslord1124]

@Grifflyer ...I always say if there is no video it didn't happen. Do you have a video of the epic crash?

Well things didn't pan out today, both of the nearby fields I was going to were full of people and/or animals. Plus as I found out, they were still a little saturated from recent rains. The moisture is not a huge concern for me, but I'd prefer to maiden a new one with nobody around...just prefer to play it safe if something were to go wrong.

Gonna try it again tomorrow morning OR tomorrow on lunch break again. Should be about the same conditions.

 

[basslord1124]

All right, it happened...the maiden flight I mean.

And...as shown by others and at least what I observed just from a ground analysis AND flight experience...the KFM wing is pretty darn durable! No major damage and trust me, I crashed it. It was sort of an all around experience...I crashed it AND I actually had a period of flight. I briefly went over the video and my camera is still having issues...before on my Edge video it cut out early and I wasn't sure if it was a dead camera battery OR the SD card. Well I can confirm that the battery is good on the camera but there must be something going on with the SD card. The camera is a Polaroid Cube. The good news though, is I got 19 minutes of footage before it finally died and in that time I know it captured the crashes and flight...sooooo footage will be coming soon.

The only issue I had (and I was eventually able to overcome it), is what I am assuming to be a horrible torque roll to the left. So bad, it would flip the wing inverted in the first seconds of flight. And my inverted skills are not there yet. This thing may teach how to do inverted if it keeps doing this! I don't know if @Hai-Lee or @mayan wish to chime in on this if they had that sort of experience with the wing.

But anyways after the experience, I have a slightly crumpled nose and a motor pod/firewall area that needs reinforcement now. And of course figure out the torque roll situation. Overall though, not bad...I'm very happy...especially since I had some success flying a wing. It flew good slow and fast IMO.

 

[Hai-Lee]

All right, it happened...the maiden flight I mean.

And...as shown by others and at least what I observed just from a ground analysis AND flight experience...the KFM wing is pretty darn durable! No major damage and trust me, I crashed it. It was sort of an all around experience...I crashed it AND I actually had a period of flight. I briefly went over the video and my camera is still having issues...before on my Edge video it cut out early and I wasn't sure if it was a dead camera battery OR the SD card. Well I can confirm that the battery is good on the camera but there must be something going on with the SD card. The camera is a Polaroid Cube. The good news though, is I got 19 minutes of footage before it finally died and in that time I know it captured the crashes and flight...sooooo footage will be coming soon.

The only issue I had (and I was eventually able to overcome it), is what I am assuming to be a horrible torque roll to the left. So bad, it would flip the wing inverted in the first seconds of flight. And my inverted skills are not there yet. This thing may teach how to do inverted if it keeps doing this! I don't know if @Hai-Lee or @mayan wish to chime in on this if they had that sort of experience with the wing.

But anyways after the experience, I have a slightly crumpled nose and a motor pod/firewall area that needs reinforcement now. And of course figure out the torque roll situation. Overall though, not bad...I'm very happy...especially since I had some success flying a wing. It flew good slow and fast IMO.

I will answer the roll issue simply by saying that you need to do or check 2 things before or at launch. Firstly that the motor thrust angle is as close to zero - zero as is possible or with just a tiny angle of up thrust.
Secondly with higher power setups launch at around 50% throttle because if the launch is slow and the motor torque is high a roll will ensue. I normally hand launch it at half throttle and try to keep it level until it builds a little speed and then of course slam the throttle to the max.

Have fun!

 

[PoorManRC]

Of course, Hai-Lee's advice sounds...sound! 😉 Having never flown a pusher - yet - I can't add anything. Do not know about thrust on them...

I seem to have good results with about 3-5 degrees down thrust and 2-3 degrees right thrust on Tractors...

I ASSUMED a Pusher would be similar. I guess not. I want to eventually do a FT Bronco as a single Motor pusher, so that's something we both need to sort out. 😉

 

[basslord1124]

I will answer the roll issue simply by saying that you need to do or check 2 things before or at launch. Firstly that the motor thrust angle is as close to zero - zero as is possible or with just a tiny angle of up thrust.
Secondly with higher power setups launch at around 50% throttle because if the launch is slow and the motor torque is high a roll will ensue. I normally hand launch it at half throttle and try to keep it level until it builds a little speed and then of course slam the throttle to the max.

Have fun!

All right, I know on my build I didn't cut any thrust angle. If I did, it was purely accidental. My firewall was coming loose by the end, so I can double check that.

As for the 2nd thing...that MAY actually be the issue. I know at times I launched it at 2/3 throttle just b/c I just didn't know its behaviors yet and may have gave it more speed than needed. Still going through video footage and I know at times I did launch it at closer to half throttle. My motor is a generic Emax red-bottom 2300KV with 5x4 3-blade prop.

Once it was airborne I really flew it nice and slow and it did very well like that. Hand launched it similar to throwing a frisbee.

 

[basslord1124]

Of course, Hai-Lee's advice sounds...sound! 😉 Having never flown a pusher - yet - I can't add anything. Do not know about thrust on them...

I seem to have good results with about 3-5 degrees down thrust and 2-3 degrees right thrust on Tractors...

I ASSUMED a Pusher would be similar. I guess not. I want to eventually do a FT Bronco as a single Motor pusher, so that's something we both need to sort out. 😉

This was my first success with a pusher...and I even tried the Long EZ but I think it had other issues going on (weight, etc).

Ya know, I can totally see the Bronco as a pusher. I think a good first pusher would be the FT Explorer...seems like a good slow flier and good intro to pusher style. I think even this KFM Wing is not a bad start for a pusher either just b/c it still flies pretty good at slow speeds.

 

[PoorManRC]

As you've described, the KFM Wing is a great idea for those of us who are still crashing a lot!! 😳 I'm glad it's durable.

I may even experiment with a 3 layer KFM on a conventional Aircraft...

 

[BATTLEAXE]

Of course, Hai-Lee's advice sounds...sound! 😉 Having never flown a pusher - yet - I can't add anything. Do not know about thrust on them...

I seem to have good results with about 3-5 degrees down thrust and 2-3 degrees right thrust on Tractors...

I ASSUMED a Pusher would be similar. I guess not. I want to eventually do a FT Bronco as a single Motor pusher, so that's something we both need to sort out. 😉

Like this...

It flew awesome, it was more of a scale flying type plane, here is a vid of me doing maneuvers with it...

You will chuckle at the end

 

[basslord1124]

Video is posted:

 

[Hai-Lee]

Video is posted:

Just a few things to be careful of.

You need the CG around the correct position but also you need to ensure that if you support the wing by the prop adaptor and the nose that the fully loaded flying wing does not drop one wing/side due to asymmetrical wing loading, (the weight on one wing is higher than the weight on the other). If there is too much difference the wing will roll over so that the weight on top of the wing becomes the weight under the wing, (like a keel on a boat).

On mine I fitted a pine skid/keel piece for the attachment of the bungee hook and to provide a damage resistant point to contact the ground/asphalt on landing. The keel piece also provides a finger point for balancing the wing and for overhead flat launches.

Apart from the launches you definitely have a flyer there and you flew it quite well for a first time attempt. As you can now attest the flying of a wing is very simple and requires no real special training. If you can fly a standard RC plane then flying a wing is not difficult, (But it is more responsive in pitch and roll for sure). Careful setup is the key to a neutral handling addition to your hangar and this one is quite robust in its standard form and if the need is there it can become made almost tank like in it crash resistance.

Well done!

Have fun!

 

[BATTLEAXE]

Video is posted:

So now that you have flown it how do you like it?

Seems like you were able to get some slow flying out of it, would be perfect for a little on board cam...

 

[PoorManRC]

Like this...
View attachment 153751
It flew awesome, it was more of a scale flying type plane, here is a vid of me doing maneuvers with it...

You will chuckle at the end

That looked and flew GREAT!! Right up until....SPLAT!! 😂😆😜
Can't say it hasn't happened to me! 😁

So, on a pusher, do I want any Thrust Angles, or just keep it neutral?

 

[PoorManRC]

Video is posted:

I really enjoyed it! When you were done crashing, it really flew nice and smooth. 👍👍

 

[BATTLEAXE]

That looked and flew GREAT!! Right up until....SPLAT!! 😂😆😜
Can't say it hasn't happened to me! 😁

So, on a pusher, do I want any Thrust Angles, or just keep it neutral?

If you are doing a Bronco or Explorer the thrust angle is built into the design. They usually require 10-15 degrees of down thrust into the wing effectively pushing the wing up. There are other designs that use no down thrust

 

[PoorManRC]

If you are doing a Bronco or Explorer the thrust angle is built into the design. They usually require 10-15 degrees of down thrust into the wing effectively pushing the wing up. There are other designs that use no down thrust

Good to know, thanks! 😉 The Bronco is definitely on my ever growing list... 😜

 

[BATTLEAXE]

Good to know, thanks! 😉 The Bronco is definitely on my ever growing list... 😜

I liked mine, although I should have flown within my and the planes limits, I would probably still have it

 

[PoorManRC]

I liked mine, although I should have flown within my and the planes limits, I would probably still have it

What fun would that have been??! 😁

 

[BATTLEAXE]

What fun would that have been??! 😁

I did get about half a dozen good flights out of it

 

[BATTLEAXE]

Might do another someday, probably a twin next time

 

[basslord1124]

Just a few things to be careful of.

You need the CG around the correct position but also you need to ensure that if you support the wing by the prop adaptor and the nose that the fully loaded flying wing does not drop one wing/side due to asymmetrical wing loading, (the weight on one wing is higher than the weight on the other). If there is too much difference the wing will roll over so that the weight on top of the wing becomes the weight under the wing, (like a keel on a boat).

On mine I fitted a pine skid/keel piece for the attachment of the bungee hook and to provide a damage resistant point to contact the ground/asphalt on landing. The keel piece also provides a finger point for balancing the wing and for overhead flat launches.

Apart from the launches you definitely have a flyer there and you flew it quite well for a first time attempt. As you can now attest the flying of a wing is very simple and requires no real special training. If you can fly a standard RC plane then flying a wing is not difficult, (But it is more responsive in pitch and roll for sure). Careful setup is the key to a neutral handling addition to your hangar and this one is quite robust in its standard form and if the need is there it can become made almost tank like in it crash resistance.

Well done!

Have fun!

Ya know...someone else sorta mentioned that and I didn't even think about it at the time. They suggested moving my battery closer to center to help in terms of lateral balance. I'll add the skid plate/keel (I don't even remember why I didn't) as I do think that will provide a good balance checker and shift whatever is needed to help with balance. After looking at it, I can see where if one side is a little heavier it could cause it to roll to one side too.

Yeah after experiencing flight with it, it wasn't that bad. Just bank and yank pretty much. I could honestly give it the throttle I want and control it only with the right stick. Once I get the kinks worked out, I'm pretty excited to see what else it can do and maybe get her up to faster speeds.