4 meter scratch build - Glass schedule / reinforcement questions

[thenated0g]

Now that is getting there. Nate you might want to increase the size of the control surfaces a little in chord and length - if they are large you can use small movements, if they are too small you are screwed.

Doc.

Yeah those are exact traces i made from the original plane. I was thinking the same thing. Speaker of control surfaces what do you think the best mix is? In one video i saw it setup as elevator and ailerons but in another forum a guy said mix it like a flying wing but have the central controls be 80 percent elevator and 20 aileron.

 

[thenated0g]

I have access to some old-school Glasflugel 604, 144" wings. 45 year old 'undercamber' profile and all... Maybe I should convert them to something like you will be building?

do it!

 

[thenated0g]

Also thinking about flush mounted spoilers mid chord in between the two control surfaces.

 

[Doc J]

Yeah those are exact traces i made from the original plane. I was thinking the same thing. Speaker of control surfaces what do you think the best mix is? In one video i saw it setup as elevator and ailerons but in another forum a guy said mix it like a flying wing but have the central controls be 80 percent elevator and 20 aileron.

I'd start with them separate if you can, but keep the mixing option in mind. Its sometimes too easy to mix stuff up and lose the effectiveness of both controls, while not knowing exactly what went wrong.

If you find your ailerons need bit of help, then mix in some elevator - the same for the elevators - dial in a bit of aileron help if you need it.

Thing to do is make the adjustments one at a time so that you know exactly what effect each is having.

Also, remember its perfectly OK to make flaps on a flying wing if you do it smart.

For the control effectiveness if you can plan on about 20 to 25% of the chord then you will be good. Having small chord controls (as you have drawn them) means that they may have to have a lot of movement to be effective, while with more chord you don't need such large movements.

Big movements on anything but flaps are best avoided - especially on a flying wing.

Cheers,

Doc.

 

[thenated0g]

Glad you said the 20-25% chord as that is what i had previous learned somewhere online and did on my booby copy. But i has seen pretty high praise in forum posts for this guys designs and assumed he had a reason for doing it. It makes me more comfortable having larger ones i may not need than too small.

Yes the flaps/spoilers on a wing thing has me concerned. Both of the places i would probably fly this (tick / sunset) have smaller landing zones and this could be a challenge to get down.

 

[Doc J]

Glad you said the 20-25% chord as that is what i had previous learned somewhere online and did on my booby copy. But i has seen pretty high praise in forum posts for this guys designs and assumed he had a reason for doing it. It makes me more comfortable having larger ones i may not need than too small.

Yes the flaps/spoilers on a wing thing has me concerned. Both of the places i would probably fly this (tick / sunset) have smaller landing zones and this could be a challenge to get down.

If the chords are large enough, then the elevators can become down flaps and the ailerons up flaps without needing dedicated surfaces. I have done it and it works.

I'd re-draw the plan and put down what you think for the controls, then maybe get some more advice on the final configuration.
Loads of people with experience here to help.

Just a thought - which sections are you thinking of using?

Cheers,

Doc.

 

[thenated0g]

No idea on sections. Up to this point i have just been doing one piece of foam. So if its pw51 or mh32 its that thru the entire wing with no changes just following that from root to wingtip. I am assuming you are talking about cutting the wing up into different sections with changing airfoils to make it fly better right? This is way beyond my knowledge. I am going to have a guy cut the cores out of blue foam (danielphantom on rcgroups). I have him cut a few things for me in the past and was easy to work with. So as long as i can explain it to him im sure he can figure it out.

Here is the updated graphic. Controls are 25% of root, extended length on elevators and moved ailerons farther inward.

Crap just now realizing how big of a flat surface im going to need to work on ONE wing lol

 

[Doc J]

No idea on sections. Up to this point i have just been doing one piece of foam. So if its pw51 or mh32 its that thru the entire wing with no changes just following that from root to wingtip. I am assuming you are talking about cutting the wing up into different sections with changing airfoils to make it fly better right? This is way beyond my knowledge. I am going to have a guy cut the cores out of blue foam (danielphantom on rcgroups). I have him cut a few things for me in the past and was easy to work with. So as long as i can explain it to him im sure he can figure it out.

Here is the updated graphic. Controls are 25% of root, extended length on elevators and moved ailerons farther inward.
View attachment 2966

Crap just now realizing how big of a flat surface im going to need to work on ONE wing lol

Hi Nate,
what is your name by the way?

Lets answer your questions:

No idea on sections. Up to this point i have just been doing one piece of foam. So if its pw51 or mh32 its that thru the entire wing with no changes just following that from root to wingtip. I am assuming you are talking about cutting the wing up into different sections with changing airfoils to make it fly better right?

For your application the PW51 would be great. I wouldn't advocate cutting up the wing into several different sections - its really arguable if this would help or not.

However, if you are going to cut the foam for one wing in two halves then I would advise blending the outboard half into a tip symmetrical section of the same thickness. Thats just for safety and will pretty much eliminate the nasty behaviour that can sometime occur on his aspect ratio wings. There is absolutely no bad point from this by the way, and if you do adopt it you will be happy at how nice and forgiving your wing is.

Here is the updated graphic. Controls are 25% of root, extended length on elevators and moved ailerons farther inward.

I think the end of the ailerons are actually too wide, but anyway that can be addressed when you cut them out. Other than that its looking pretty damn stick.

What are you going to do for the fuselage? I had made a couple of nice ones from broken scale fuses with the back adapted to take a new fin - they look great! I wish I had some pics to show you but I lost them all some years back.

Doc.

 

[bracesport]

@thenated0g - love the thread so far - 4m - woo ha, that will be awesome! The forward swept wing reminds me of the Durafly Excalibur - yours will be equally spectacular!

Did you already post your 2.4m plank here somewhere? ?

 

[thenated0g]

Nate or Nathan is fine. I'm mostly active on Instagram if your into that: Instagram.com

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I have been wanting to try mold making. I think a two part mold and fiberglass the two halves after curing will be my start. First with some ultracal or maybe epoxy and cabosil as a tooling coat and than backed by ultracal. Make the buck out of mdf probably. My goal is flying in a year and a half so i have time to try different things.

 

[Doc J]

Nate, I used an old DG600 front end and replaced the wing stubs with a new section, then I bondo'ed them in. The tail end was faired off and a new fin added. Really easy way to get a great looking fuselage plug without too much wood shavings or foam dust. Making the fuse mould was pretty simple at this size - I think it was only about 24" long.

For a "broken model" plug, In fact the front end of pretty much any older model will do because they are a bit bigger than we use nowadays.

Saves an awful lot of work to make the fuselage mould unless you want a very special shaped front.

Just an idea - cheers,

Doc.

 

[Doc J]

My "Broken fuselage" model ended up looking a lot like this, Nate - but without the little stab on the top

Also here is the Gooney Bird that I designed about 10 years ago. RCRCM made the controls the wrong size and too small but apparently it still flies OK - if a bit limited.

Just for interest,

Doc.

 

[thenated0g]

That is a geat idea. I will probably still attempt mold making as fuselages are still something im just never happy with, but i will keep an eye on rcgroups sales to see if i can find anything like that. Gooney looks pretty cool. Eventually i will own a nice manufactured plane, but i really enjoy messing around on stuff in the shop even if it doesnt come out great. Plus after scratch building for years the jump in price to a moldy is pretty significant lol.

 

[bracesport]

Nathan - I was thinking to try 3D printing some mould females in ABS then support them with resin - ABS sands and paints well - alternatively, after the Ridge Rat experience, I was contemplating 3D printing a 'fuse' shell and then use the CF braided tube over the top with the epoxy?

thoughts?

 

[Doc J]

Nathan - I was thinking to try 3D printing some mould females in ABS then support them with resin - ABS sands and paints well - alternatively, after the Ridge Rat experience, I was contemplating 3D printing a 'fuse' shell and then use the CF braided tube over the top with the epoxy?

thoughts?

Both good ideas!

Doc.

 

[thenated0g]

Carbon but same idea

 

[Diceman]

Nate, I love the drawing! What program are you using to make it? I need to make pictures (silhouettes) of planes that I can make into stickers or put on shirts, but there are only a handful on the net. I would love to be able to make my own like you did. Let me know. Thanks! You can message me on FB.

 

[thenated0g]

Nate, I love the drawing! What program are you using to make it? I need to make pictures (silhouettes) of planes that I can make into stickers or put on shirts, but there are only a handful on the net. I would love to be able to make my own like you did. Let me know. Thanks! You can message me on FB.

Inkscape, its a free open source svg program. I use it for all my designing. Both RC planes and exporting out for cricut vinyl sticker cutting. I design everything in real world sizes, meaning if i printed it out it would match 1:1 its correct size. This helps as i can take electronic sizes and make box to represent it on a plane to see if it will fit or not. Heres a couple more snapshots from this file to show you how i use it to figure out how much material i need to order or even servo cable length:

 

[Wayne]

Looking good! Better make 2 so that I can fly mine next to yours.

Ridge Rat - Is that the name? You know that is a vintage slope glider?

I learned how to fly ailerons with a Ridge Rat.

 

[Doc J]

Looking good! Better make 2 so that I can fly mine next to yours.

Ridge Rat - Is that the name? You know that is a vintage slope glider?

I learned how to fly ailerons with a Ridge Rat.

Pretty sure that was the one we use to fly in the UK - did it come from there?

Doc.