Pattern build, scratch (was:Plans or specs-)
 

Are there any free plans for a .60 size pattern planes?
Or could someone share the specs for a plane like this.

I would like to design and build a pattern type plane. Just for a sport type flying.

Thanks
EZ

PS, this thread turned into a build log, starting at about #7 or #8 post.

RE: Plans or specs
 

At one time, there was a thread that listed plans for many different pattern planes...

http://www.rcuniverse.com/forum/List...2600745/tm.htm

RE: Plans or specs
 

How about any 3 view of pattern airplanes on the net. I just want to get some proportions.

EZ

RE: Plans or specs
 

try in www.oxai-rc.com/showroom

with that pictures im building my 46 size pattern plane, not finished yet, buy has a great proportion and style
good luck

RE: Plans or specs
 

humm, the link doesnt work, just go to oxai web page:)

RE: Plans or specs
 

for example

RE: Plans or specs
 

perfect, thats what I was looking for.

thanks
EZ

RE: Plans or specs
 

hey cncfoam, are you drawing any plans? or will ?
bye

RE: Plans or specs
 

Yes, Im going to do something. I have a cnc foam cutter and a cnc router that I built.
I am also getting set up to do some 3D router work. Molds and the other parts. I have a thread here on that subject. [link=http://www.rcuniverse.com/forum/m_4080595/tm.htm]link to molding[/link]

I have not done any building of planes, but I love planes and technology.

here are a few things that I have done with my foam cutter.
Hurley Extra 300 foam kit.
Foam core for an ice boat, 26 foot length, 4.5 feet at root and 1.5 foot at tip.

I will probably do a thread of this build, of my design of a pattern plane. I will start out with drawings, in Solidworks and Autocad. then transfer into a build. Obviously with some help from the experts.

Eric

RE: Plans or specs
 

OK, I will start with the basic planform. Here is what I have so far.

I am going to use the planform of the Pinnacle, in the picture above. After scaling it to my size, here is what I came up with.

Main wing span = 65"
16.375" at root
7" at tip

Stab span = 26.4"
8.5" at root
5" at tip

Fuse length, from tip of spinner to tip of rudder. 67.25"
I will probably make the Fuse 5" wide at the cockpit.

Length from LE of main, at root, to LE of Stab = 39"

How I came up with these dimensions, I just uploaded picture from above, imported it into Acad. Traced the planform, scaled it up so the wing span was 65"

Any suggestions on Airfoils for Main and Stabs?
What are some of the more popular airfoils are pattern planes using?

EZ

RE: Plans or specs
 

Wow, your CNC equipment looks fab.!
Wing airfoil: NACA 64012.
Possible modifications: thinnned down to 9 or 10 % at tip.
& T/E thickness increased to around 3-5 mm.
OR NACA 63012, same mods.

Stab: NACA 0010 or 0008

RE: Plans or specs
 

I forgot to ask about dihedral.

what are the recomendations for that?

EZ

RE: Plans or specs
 

Dihedral: don't know the theory, but current designs have the top surface more or less flat, with the dihedral provided by the difference in thickness between root and tip.
Again,in practice, very few designs get this spot-on---the test being how much rudder-to-aileron mix is needed for no roll when rudder is applied.
As a general rule ,the more "low wing" the design, the more dihedral will be required, and the nearer it is to mid wing,the less.

RE: Plans or specs
 

Here is the lay out (templates) for the main wings. Red is the root, 16.375" chord, Tip is in Blue, 7" chord. Cores will be 29", I will add balsa tips and cut the root to match the fuse, (later)
I have the TE of the tip chord 2.3" forward of TE of root chord, this will give me the planform. Also, I have the tops of the wings flat and the dihedral is on the bottom, as stated in the previous post.
This drawing is like looking at the templates( if I had to make them) from these drawings, I need to edit them further in order to make cut files for the cnc foam cutter.

I used the naca64012, but I forgot to thin the tip profile.

Here are the questions I need answered.

For construction, do most people cut off the LE of the core, if so, how much?... put skin on, then glue a balsa LE on and sand to shape. Or is there another method, Like...Leave the LE in the foam core and try to wrap the balsa around LE.

Second, as far as a wing tube goes, what are the methods to put the hole in the cores?

This is the way I do it now, I take a block of foam, cut out a pocket on the top of the block, where the end of the wing tube will be in the wing. Put my hole cutting jig on my machine, cut out the wing tube hole, then take the jig off. put on the regular wire, then I cut the wing core.(The wing core and the shucks are cut at the same time) Im sure you dont understand this, but my point is that it takes alot of time to do it this way. Because I can zero my wires, I know that i am accurate with the locations of the holes. But, I was wondering how others do it quickly and Accurately.

EZ

RE: Plans or specs
 

Excellent page on pattern wing construction:

http://www.mackrc.net/patternwings2/index.htm

Lots of pics, very detailed explanations and procedure.


Mark

RE: Plans or specs
 

here is the chords with the tip scaled down to 10% thick

EZ

RE: Plans or specs
 

I did the mock up of the main wings with wing tubes.

Ive drawn in a 5/8" wing tube that extends 10.625" into the wing.

Is this wing tube diameter big enough? Should I use 7/8"?

Does the tube go into the wing far enough? Im using 24" wing tube

Each wing panel will be about 29" in length. wing root will be cut at an angle to match the fuse sides. Fuse will be about 5" wide at the LE of wing panels, add the wing panels and the fuse, you should get about 65" span.

EZ

RE: Plans or specs
 

I worked on the fuse. this is what it will look like from the front of the LE of the H. stabs, to the nose of the plane.

I will have to work on the cowl, later. I will throw some wings on next, when I get some time.

EZ

RE: Plans or specs
 

Since no one else chimed in, I will throw my $.02 in (Canadian $$ at that ;)). I'm no pattern airframe expert, but I am a mechanical engineer and I can keep my eyes open to structural details as well as most people...

I would use a 3/4" tube, 5/8" seems a touch small for a 90 size model. Bending strength of a round section goes as the cube of the diameter, so your 5/8" tube is significantly weaker than the 3/4" one. I would also move the tube back in the wing panel some, too. It looks too far forward to me at the outer end of the tube. I would try to straddle the high point of the wing with the tube, having the tube behind the high point a bit at the root and in front of it at the outer end of the tube.

The 24" length should be OK. Some of the 2M planes use a 30" tube, so you are not too far off. Just be sure to reinforce the skins where the sub rib is at the end of the tube.


Mark

RE: Pattern build, scratch (was:Plans or specs-)
 

Hi gents ..Very interesting thread. My 2 cents !! ( Actually it is Kroner ) Go with the 7/8 " PBG size as a minimum and better yet install the 30 mm diameter, because theres other issues than bending involved i.e. poor landings, long grass to catch a wing etc.

Regards Eggert

RE: Pattern build, scratch (was:Plans or specs-)
 

Hi

Most of the aircraft that I have seen lately have been using the pbg 7/8 " wing tube.They seem to have the right strength etc, you could use the 5/8 " quite easily the wall thickness off both are very similiar.

What 3d program are you using for your modeling, I have just done the plans for the Black Magic, Quest and the shinden other peoples designs

Thanks

Troy

RE: Pattern build, scratch (was:Plans or specs-)
 

Thanks for the information on the wing tubes.

Any and all comments are welcome. Questions too.


Update...

I lowered the top of the firewall, so that the slope of the top of the fuse, near the front of the fuse, will match up with the cone. Hard to see, but I did do it.

Also widened the lower half of the firewall, it looked to thin, it looks better.

Added top view.

RE: Pattern build, scratch (was:Plans or specs-)
 

what is PBG?

Actually it will be a .60 2 stroke. But I will use 7/8"

I use solidworks.

EZ

RE: Pattern build, scratch (was:Plans or specs-)
 

A friend of mine is building a "Boxer" pattern plane from plans with some modifications. Very nice so far. He is enlarging the fuselage to accomodate an OS-1.20 AX engine with a Mueller Header and a Tuned Pipe. He also is enlarging the fuselage by adding a bit more height to the rear of the fuselage, increasing the size of the horizontal and vertical stabs, and making the wing length equal to the fuselage length. Should be nice when he is done. He's a craftsman.

RE: Pattern build, scratch (was:Plans or specs-)
 

Hi there CNCFoam,

PBG is PBG Composites , they make very nice, strong and light [link=http://www.pbgcomposites.com/products/carbon_tubes/CarbonTubes.htm]Wing tubes[/link] etc. (these wing tubes and sockets are extremely nice) you can get them from easily from [link=http://www.radiosouthrc.com/thumbnail.asp?cid=103] RadioSouth [/link] Nice modelling, keep up da good work!