"Mini Buzz" Blended Wing Project

[thenated0g]

The leading edges are actually sanding back just fine even though the vacuum isnt as much as im used to. The Gorilla glue fills in the gaps and sands nice.
Need to figure out which servos im using and get holes in for them and wires before i glue these two parts together. Figure out elevon size, i havent looked at the original Gizmo thread to see what he was doing. I think i usually do 20-25% of that wing sections root cord.

Also figure out what cg will be, tape this all together, including vertical, and put as much lead as i can ahead of time in the two sides of the nose to make it easier later.

 

[slopenutz]

I could use a couple of carbon fiber bagged Sharpies. Can never have too much bling on the workbench.

 

[Yotaman1985]

While waiting for my wing cores to arrive, I figured I would sort out the tail. I had a couple spare fins from my SAB Tortuga that were warped and thought I would try to heat/straighten them as they were junk anyways. Ended up working out rather well and was able to get one nice and straight. Cut it down and created some hard points with epoxy and a threaded brass insert for mounting.

Planning to try cutting a slot in the wing cores for the fin and then filling it in (around the fin) with epoxy to create a hard slot that the fin can slip into and bolt in through the bottom of the wing with nylon screws. We'll see if it actually works out how Im thinking... lol

Also in the mean time, I took the first Z1 fin I made and cut it down to be the vertical fin for the practice wing which I am now calling my "Scrap" plane. Its not pretty and looks pretty goofy but should fly if I can get the CG right

 

[Wayne]

Loving the projects guys!! Keep it up.

Nate I probably missed it, but what wood are you sheeting with?

 

[thenated0g]

@Wayne Poplar Veneer, unbacked. I had picked it up pretty cheap but now they are out of stock, need to find some more actually.
I dont know enough about the wood to know what else would be usable/comparable: https://www.veneersupplies.com/

I took some random scraps i had of veneer and fiberglass and made up a tail. Think im out of carbon tow so just threw on some carbon threads i pulled out of some 12oz cloth.

 

[thenated0g]

@Yotaman1985 what were you thinking about doing for the wingtips?

Since your doing cloth you could cut them into a shape and sand. I am thinking about adding some solid balsa blocks and hand shaping.

 

[Yotaman1985]

@Yotaman1985 what were you thinking about doing for the wingtips?

Since your doing cloth you could cut them into a shape and sand. I am thinking about adding some solid balsa blocks and hand shaping.

I was planning to just shape the foam by sanding it into a curve on the tip like the carboard cutout I made. I do like the balsa tip idea too though

 

[thenated0g]

Saving these here so i dont have to go find them in the rcgroups thread again
Looking at elevon size and electronics locations

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[Yotaman1985]

Got my Scrap wing done and ready for a maiden. Keeping in the Scrap theme, I threw in some old parkzone servos and an old spektrum receiver. Came out to 8.25 oz so we'll see how it flies with only a 24" span. Turned out better than I expected honestly. Lol

 

[Doc James Hammond]

Got my Scrap wing done and ready for a maiden. Keeping in the Scrap theme, I threw in some old parkzone servos and an old spektrum receiver. Came out to 8.25 oz so we'll see how it flies with only a 24" span. Turned out better than I expected honestly. Lol

With respect that fin might be better back a little like some of your other pics. If not you might find that you have some weird crosswind behaviour. But at least people are resisting the temptation to put the fin(s) at the tips. The fin or fins at the back especially with a stinger setup works but those lovely little wingtip fins will rob you of performance.
Trust me they do not work even on conventional gliders until you get to 6m or above. On flying wings they force the model into quasi stability at times when you don’t need it.

But they save a lot of fuel.

Doc

 

[Yotaman1985]

With respect that fin might be better back a little like some of your other pics. If not you might find that you have some weird crosswind behaviour. But at least people are resisting the temptation to put the fin(s) at the tips. The fin or fins at the back especially with a stinger setup works but those lovely little wingtip fins will rob you of performance.
Trust me they do not work even on conventional gliders until you get to 6m or above. On flying wings they force the model into quasi stability at times when you don’t need it.

But they save a lot of fuel.

Doc

Thanks for the info Doc, this was just a pile of random parts I was doing mostly for the heck of it so not too worried about this one. Ill keep that fin info in mind though for when I build the actual glider.

 

[Doc James Hammond]

Thanks for the info Doc, this was just a pile of random parts I was doing mostly for the heck of it so not too worried about this one. Ill keep that fin info in mind though for when I build the actual glider.

Looking damn good. Love the step by step approach - best way to get it right.

Doc

 

[Yotaman1985]

Got my cores delivered this week and I have made some progress on them. Ended up designing and 3d printing a tail mount. Printed it out of Carbon Fiber PLA and the fin will mount with two nylon bolts so hopefully if it gets hit, it will break the bolts first.

Got the whole thing glued together tonight and now I need to shape wingtips and figure out electronics placement/CG before I start prepping for bagging. Really like how its looking so far though

 

[Wayne]

Sweet - is it done yet? LOL

 

[Yotaman1985]

Found a CG calculator for multi panel wings and this is what it came up with. Anybody see anything wrong with using 4.25" as a starting point for CG?

 

[thenated0g]

on my big starfire i did static margin of 3...that page always messes me up and i have to ask @Red WTH i enter lol
On the old cg calcs, which all seem to be dead links now, i would do 22% cg.

 

[thenated0g]

RC Groups - View Single Post - Static margin and how to calculate it

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"Putting the CG at about 22% MAC is usually a decent place to start for a plank style flying wing. That would give you a 3% static margin.

For a swept flying wing, starting with a 5% SM may be safer for the first flights, and then the CG can be adjusted to get the desired pitch response characteristics. A 5% SM would be at 20% of the MAC."

 

[Yotaman1985]

RC Groups - View Single Post - Static margin and how to calculate it

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"Putting the CG at about 22% MAC is usually a decent place to start for a plank style flying wing. That would give you a 3% static margin.

For a swept flying wing, starting with a 5% SM may be safer for the first flights, and then the CG can be adjusted to get the desired pitch response characteristics. A 5% SM would be at 20% of the MAC."

Thanks Nate, I was putting the SM in based on the little blurb about it on the CG calc page. I think the 4.25" CG is with 4% SM.

 

[thenated0g]

sounds like that should work and if you want you can move it back a little later.

 

[Red]

Thanks Nate, I was putting the SM in based on the little blurb about it on the CG calc page. I think the 4.25" CG is with 4% SM.

That's safe, tweak it later.