"Mini Buzz" Blended Wing Project

[Yotaman1985]

Got a little more work done on the cores today. Rounded off the wing tips and smoothed it out. Did some preliminary electronics layout to figure out CG and added 20 grams of lead shot to get somewhat close before I bag it. Also mounted the fin with the screws and super happy with how secure it feels (will be even better when bagged). Planning to reinforce key spots with kevlar and extra carbon. Hoping to maybe bag it Tuesday if I can find time to prep everything.

 

[Doc J]

Got a little more work done on the cores today. Rounded off the wing tips and smoothed it out. Did some preliminary electronics layout to figure out CG and added 20 grams of lead shot to get somewhat close before I bag it. Also mounted the fin with the screws and super happy with how secure it feels (will be even better when bagged). Planning to reinforce key spots with kevlar and extra carbon. Hoping to maybe bag it Tuesday if I can find time to prep everything.

Now that is going to work fine.

Doc.

 

[Yotaman1985]

Well, I bagged the Mini Buzz yesterday. Dont have any photos to show for it yet though and didnt take any during the process as it was a bit messy... I was also feeling pretty defeated as my first attempt on Monday failed miserably. I didnt realize until I went to close the mylar sandwich after wetting out all the carbon and kevlar that I had done it on the wrong side of the mylar sheets. Huge rookie mistake and it ended up costing me a bit of carbon, kevlar and epoxy but fortunately not the foam cores.

Second attempt went better and seemed to bag well. I doubled up carbon in some areas like where the servo pockets will be and the electronics compartment as well as adding some kevlar on the nose/belly, around the fin mount and trailing edges. not sure how much this will help but I figured it wouldnt hurt. I might un-bag it tonight and will post pics once I do. Foam cores with the 20 grams of lead in the nose weighed 45 grams before bagging so we will see how heavy it got with the carbon. Im not going for super light with this one. My goal is a strong version that can handle some wind and possible rough start with figuring out CG.

 

[thenated0g]

Nice, i need to get back on it. Been trying to finish my Aeroic gremlin so i have room to work on this stuff more.

 

[Yotaman1985]

Nice, i need to get back on it. Been trying to finish my Aeroic gremlin so i have room to work on this stuff more.

I had been kinda putting it off because I was nervous of messing it up... Lol Ended up doing that anyways but at least the cores were still usable. We'll see what it looks like when I un-bag it. I think the wingtips didnt conform as well as they could have. Needed to make relief cuts in the mylar but forgot until it was too late.

 

[Yotaman1985]

Un-bagged the Mini Buzz tonight. Turned out alright, Id say 6 out of 10. Wingtips didnt conform as well as I had hoped and its a bit wavy but should fly alright. Now I need to trim and sand everything and see what I need to fix... lol

 

[Wayne]

Making big strides.

 

[Doc James Hammond]

Un-bagged the Mini Buzz tonight. Turned out alright, Id say 6 out of 10. Wingtips didnt conform as well as I had hoped and its a bit wavy but should fly alright. Now I need to trim and sand everything and see what I need to fix... lol

I think the vacuum pressure could be lower, maybe?

Doc.

 

[Yotaman1985]

I think the vacuum pressure could be lower, maybe?

Doc.

Thanks for the thought, Ill possibly try that next time. Im using a food vacuum sealer so not sure how much its pulling other than visually.

 

[Wayne]

I have a lot of fiberglass we can send you for testing with. Save the spendy cloth once you have things fine tuned..? Let us know and the guys can get a bunch out your way.

 

[Yotaman1985]

I have a lot of fiberglass we can send you for testing with. Save the spendy cloth once you have things fine tuned..? Let us know and the guys can get a bunch out your way.

That would be awesome Wayne, thank you!

 

[Wayne]

send us an email: contact@alofthobbies.com and we will get that out on Monday.

 

[Doc James Hammond]

Thanks for the thought, Ill possibly try that next time. Im using a food vacuum sealer so not sure how much its pulling other than visually.

Judging by the surface of the lamination, it may not be as much as you need. It should conform to your cores, which looked pretty good.

You have a pressure range of up to 1 Atmosphere, or 14 PSIg, or 1Kg/Cm2 to use, which, even over your smaller-sized wing, is quite a lot, much more than you could apply with, say, weights or water tanks, etc.

I have collapsed quite dense white foam cores under vacuum, and have on occasion had to turn the pressure to a lighter setting, around 12 to 13 PSIg.

In this case, more (Availability) is more.

Cheer,

Doc.

 

[thenated0g]

Started working on the woody.
I am going to use these little 5g Emax 9052 MG servos.
Bottom hinged as usual.
I have some 1/2 fiberglass tape ill use on the seams.
If i can keep the epoxy from getting everywhere during the joining process, i may try for a clear coat on the wood instead of iron on covering.

 

[Wayne]

If you use WBPU, make sure you brush it on both sides at the same time (one side, then immediately do the other side before the first dries), otherwise the trailing edge will warp in the direction that is wetted first. Ask me how I know.

Looks very nice.

 

[thenated0g]

Yeah that is the plan. I really like how that looks on the Sequoia.
After this woody one ill try some fiberglass and than Carbon.

 

[Doc James Hammond]

View attachment 23386

Started working on the woody.
I am going to use these little 5g Emax 9052 MG servos.
Bottom hinged as usual.
I have some 1/2 fiberglass tape ill use on the seams.
If i can keep the epoxy from getting everywhere during the joining process, i may try for a clear coat on the wood instead of iron on covering.

I see you are going for a bust on the elevon size, Nate.

I might be a little careful with that, as it looks like you are close to, or above, the half chord size at the tips, and that's always where the wobbly stuff starts, even with an all-wing configuration. I think that you may have a mite of trouble taming the control inputs to achieve smooth flight at this size and position. Tiny fractions of a degree could make a significant difference between a slick, swift wing and a mushy performer.

Might I humbly suggest a tapered elevon down to 25% - or a bit less - of the tip chord?

Doc

 

[thenated0g]

OK, ill try that on the next one. I usually go 25% at the root and do that all the way across, but easy to do 25% on each side.

 

[Wayne]

Good point.

 

[Doc James Hammond]

OK, ill try that on the next one. I usually go 25% at the root and do that all the way across, but easy to do 25% on each side.

OK, ill try that on the next one. I usually go 25% at the root and do that all the way across, but easy to do 25% on each side.

Got it - I'm just worried that you're building in potential problems, so whatever you expect from your otherwise good-looking experimental design won't be there.

The results of having the wrong-sized ailerons (Or elevons) in the wrong place can lead to endless frustration in getting an otherwise sound design to fly well.

I see Wayne has chipped in. Case in point: He will remember the "DENSITY"

I hope it works out okay, though. Air does weird and sometimes unsuspected things across wings. I have just done a shedload of calculations on that, which is why I am fresh.

Cheers,

Doc.