Divinity, 42" KFm4 Slowfying wing. - Page 150 - RC Groups
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May 16, 2018, 06:36 AM
I Look, Listen, and Learn
Timbo383's Avatar
You can also try rare earth Neodymium magnets. I have some very small but strong, about 3 mm in diameter, ones that will hold in flight but can pop apart for transport or hard landings. Paid 2 or 3 dollars for them online somewhere awhile ago, haven't found any this small in any store. Anyways, just make some small holes and epoxy...or I like gorilla glue, a little more flexible... 2 in each wing side and in each winglet.
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May 16, 2018, 07:17 AM
Multirotor Enthusiast
Blacky's Boy's Avatar
Oh trust me, I know about rare earth magents! I've used them in several applications in my day job (machine designer)

Anyway, I cut up all the pieces for the Divinity II and will start assembly tonight,...after reading about the assembly order here. I want to see if you join the bottom wing halves first and then install the KFM steps OR (like I'm used to) make each wing halve complete with the KFM step, sand the joint smooth and THEN join both halves together.
May 16, 2018, 07:36 AM
I Look, Listen, and Learn
Timbo383's Avatar
I think either way will work out the same, I say do the way you're used to doing things to make it the easiest and simplest for you.
May 16, 2018, 08:50 AM
Multirotor Enthusiast
Blacky's Boy's Avatar
I haven't looked through the entire thread but has anyone made a Divinity with a KFM3 wing? I imagine it's be pretty easy. The reason I ask is that the KFM3 wings on my Blue Baby 42 are super strong and light. Even with the 1/4" bbq skewer spar.

Edit to add:
Amazing what a little searching can find....
https://www.rcgroups.com/forums/show...postcount=2207

So it looks like a couple people have made it with a KFm3 wing. I may try that after I make this one. I will say this, I love the fact that it's such a SIMPLE build. If I had more energy last night I could have glued up the wings already and be assembling it tonight
Last edited by Blacky's Boy; May 16, 2018 at 08:53 AM. Reason: added link
May 16, 2018, 06:35 PM
I Look, Listen, and Learn
Timbo383's Avatar
It looks like to me that you want a more "floatie" divinity. I'm thinking that maybe you can try to mount the winglets higher on the wings. Leave about 3/4 to an inch on the bottom and the rest above the wing, increasing the survival rate of the winglets on landings.
May 16, 2018, 08:19 PM
Multirotor Enthusiast
Blacky's Boy's Avatar
Quote:
Originally Posted by Timbo383
It looks like to me that you want a more "floatie" divinity. I'm thinking that maybe you can try to mount the winglets higher on the wings. Leave about 3/4 to an inch on the bottom and the rest above the wing, increasing the survival rate of the winglets on landings.
Thanks (again) for the advice.

I started the glue up tonight. The wings/fuselage are pretty much good to go for tomorrow. I may hold off on adding the winglets until last. Just to make it easier to handle
May 17, 2018, 03:08 PM
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Blacky's Boy's Avatar
Not sure if I screwed up or not. I followed the plans and made (what looks like) a KFM wing. It just has one step. And I didn't add the spacer at the back like so many others had. I'm thinking that I will just plow ahead and see how it behaves.
May 17, 2018, 03:32 PM
I Look, Listen, and Learn
Timbo383's Avatar
Going back an rereading your posts you mention divinity " 2", there are two different divinitys. This is the first one, you may have seen the second one that you thought you were building which I think is a KFM3 or 7, it looks different.
I built my divinity 1 without any spacers and it flew great, adding the increase hight of the spacer will give the plane more lift tho.
May 17, 2018, 03:58 PM
I Look, Listen, and Learn
Timbo383's Avatar
Or maybe you are wondering how a wing that looks so flat can fly good.
May 17, 2018, 06:17 PM
Multirotor Enthusiast
Blacky's Boy's Avatar
Quote:
Originally Posted by Timbo383
Or maybe you are wondering how a wing that looks so flat can fly good.
Here's a shot of my progress so far.

Btw, I just checked and I was working off the plans titled "Divinty2_Parts_Full" that were featured on the first page of this thread.

I think I'm going to glue in some 3/16" wooden dowels as spars on the wings. They seem very flexible. Sitting them flat on my desk I can bend them up almost 5" if I press down in the center and pull up at the wing tips without even trying. Or is this normal?

As far as mounting the motor I'm thinking that I need to add a small piece of MPF above and below the fuse to give me some area to glue to.
May 17, 2018, 09:33 PM
serial scratchbuilder
Granted's Avatar
I used 3/16" poplar dowel on the LE and main spar and built an "A" frame for stiffness, worked well. Motor mount is a 1/8" ply disc with two pieces of dowel glued into holes in it and running forward, tying into the main spar.
May 17, 2018, 10:11 PM
Registered User
Divinity2_parts_full are the plans for the 48" Divinity II that was a kfm6 airfoil. This thread is for the original 42" divinity with a kfm4 airfoil.
May 18, 2018, 01:44 AM
Registered User
so you know the saying going around "light is might?" there might be some truth to that, I put my pizza box flyer on a diet, lost 60g and what do you know. much better no spar it's very flexible. did use fibre tape though. I would have went with 1 spar, probably carbon fibre for more strength and keeping it light. and fibre tape on the leading edges
Quote:
Originally Posted by Granted
I used 3/16" poplar dowel on the LE and main spar and built an "A" frame for stiffness, worked well. Motor mount is a 1/8" ply disc with two pieces of dowel glued into holes in it and running forward, tying into the main spar.
May 19, 2018, 08:58 PM
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Blacky's Boy's Avatar

Ready for electronics


I never added a spar. I decided to go with some vinyl packing tape to stiffen up the frame and make it (somewhat) more resistant to crashes.

Since I had a lot of red tape, that's what I went with. I also added some black for a contrast. The bottom is all red and the top is red and black.

After adding the tape it comes in at 151g. I weighed the servos, 2200 mah Lipo, esc, motor, prop, control rods, horns, and rx and they came to about 333g. So I estimate it's AUW at about 484g.
Yesterday, 06:43 PM
Multirotor Enthusiast
Blacky's Boy's Avatar

Finished and ready to maiden....


Ok, my KFm Divinity II is all built and the electronics have been installed. I marked the CG location as 7-1/2" back from the LE and gave it a glide test last night in the back yard. The grass wasn't high enough so a "real" test will need to be done before I maiden at my club's flying site. There is a nice patch of tall grass at the end of the field that is perfect for this

Since the weather turned sour I had some time to program my DX9 for this. I gave it a real thorough going over and it looks like it operates per spec.

Here's the specs:
428g AUW
Sunnsky X2219-9 1400kv Motor
Gemfan 8x4E Prop
1300mAh Lipo
20a Emax BLHeli ESC
OrangeRx R615X
(2) Durbo Micro Pushrods
(2)TechOne 9g Servos

If you notice, I wrote KFm Divinity II and NOT KFm4. That's because I screwed up and blindly followed the plans. They call for only (2) each of the KFm steps where they should call for (4) [Top and Bottom]. If I had watched that great video ApachePilot made I would have known. That really should be moved to the first page with the plans.......

But truthfully, this was such an EASY build that I can make a whole new Divinty in about and evening.


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