Have we tried to do a collaborative effort in designing and building a pattern plane? With all the brilliant minds in RCU, I think we can design a very nice pattern plane that is really owned by everyone. We can upload and download DXF files in sharebigfile.com while we go along and hopefully end up with a brilliant design by next summer. Of course everyone is invited to participate but here are the rules.


1. It must fit the current FAI rules for dimensions and weight.
2. It must be a "roach" all wood and/or foam wings.
3. Please be constructive.


The initial DXF file is uploaded here and I have attached the drawing of it.
http://www.sharebigfile.com/file/728...Plane.dwg.html

Tell me what you think!

Well, I have only been here a week, and am myself making my first design & build, so I wont participate for obvious reasons, but can i suggest you add to the rules that it be a 'Could be to scale'? I know it would more than likely turn out like that anyway, but still...

Well, I think you need to more tightly define your goals and design criteria. Things that come to mind are:

1) glow/gas/electric power?
2) What are you trying to improve upon from existing designs? Better rolls, snaps, loops, what?
3) One piece wing or two?
4) All wood (cowl, canopy) or wood airframe with composite bits added?


Not trying to be a killjoy, just being practical.

And on a personal preference note - why not a bipe?


Mark

Mark,

I completely understand what you're saying. I was thinking that we all can agree on certain criteria such as the ones you suggested above. How about:

1. Nitro...built around the OS 160. This is cheap enough for many modelers who don't want to spend incredible amounts of money for a YS140 or something of that nature. Yet, the design will lend itself to the more expensive engines. As for electric, truthfully, I have to say that at least for me, just the initial outlay of motor and the lipos to drive about 2KW strikes fear to my bank account. At least with the OS 160 or even a more powerful Mintor engine would be more cost effective and should cut through the air without weathervaning too much. Heck let's make it flyable for any 2 stroke 120 size engine.

2. About improving existing designs, that's kind of difficult to say because I haven't flown many different pattern planes. I did own a Typhoon 2000 and I have to agree with most that the snapping ability needed some help. Other than that, it was fine. I guess I want a dead nuts plane. Something that is very neutral and will KE without trim, snap correctly, (ie: stall the wing but controllable stop at 1/4 snaps), etc. There are many designs out there that will do that but in this case, I'm thinking that if one brain can make a good design, then a hundred brains with something constructive to input would be phenomenal.

3. One or two piece wing. Since this is a roach, I was thinking about building from a crutch, much like several designs out there like the Typhoon. Therefore, I want to make it a 2 piece wing. This makes it easier to build and align accurately. If anyone has a better idea, please put it down.

4. I was thinking of a wood plane with come composite stuff for the cowl, canopy and possibly the belly. The fiberglass cowl because it can be cut up with cooling holes for different engines. I'm alsop opting for a fiberglass canopy so it will be an easier build. As for the belly of the plane, same as the cowl, some people might fly this plane for sport only and will use mousse can tuned pipes on a Magnum 120 s-stroke or the latest Hattori pipe on a brand spankin' new Mintor 170, YS 170 or OS 200 (the last two not for the public yet). Once we finalize a design, I'll make the plug and mold for the items and send you guys the parts just for shipping cost...and possibly just the amount of material used. No payment for the labor since we will all be working on our planes at the same time.

Basically, the deal is to make a pattern plane with a bunch of folks here willing to submit their design ideas that will be a true collaboration for a great flying plane. While pattern pilots can have wither a new primary plane that they helped design or a great secondary plane, sports fliers can have one heck of an awesome, point-it-where-you-want-it plane. I think this is a win-win situation for everyone.

If we have people that can design, people that have access to CNC routers, lasers, and wing cutters involved, it would be a much easier task.

Butch

hmmm why not?

I like the concept (collaboration), but I don't like the prospects for mutual agreement. Pattern guys (including myself) in particular will be steadfast in what they perceive as the best design for each component of the airplane....therefore getting enough agreement to finish the design may be the most difficult task of the whole project.[:@]

My initial reaction is that I really like the fuse, but I would change the wing planform a bit. Perhaps a double taper with less sweep?

Gotta say, the Bipe idea is growing on me.
Like when you look at a parking lot full of Cameros & Mustangs, the Baracuda or Javelin will draw more folks

mcmike,

NICE!!! I like the staggerwing. Ye gads that's a tall fuse. If you want, you can put the file up on the sharebigfile.com site as well so we all can share it. PM me so I can give you the id and password to upload the file. Then you can get the url and we can all download it from there. I'm just using the sharebigfile site because it's free and they have 500MB of space...more than enough to have several iterations of designs.

flyintexan,

I understand what you're saying about particular design characteristics and the concept of best design. This is what the forum's all about, isn't it? There's also many things that people could change even after the design has been made. The wing planform and location could be changed to suit the person building it. Once we have at least one plane made, it can be tested by pattern pilots to see what changes are needed...of course that's a matter of preference but we can get close to something everyone will approve and then each will be able to tweak the incidences, airfoils, planform, and locations of the flying surfaces. That's why I want to have a repository of modifications, kind of like a document control to see what people want and get their input. For example, you want the wing planform to be different, you can go to the site, download the drawing, modify it to your liking such as less sweep, (the wing does have a double taper) or a higher aspect or taper ratio or even a new airfoil altogether. Now you can upload it to the site, (PM me for the ID and password) and post your changes here to the forum. Now the design is shared with everyone to check and add their input.



I'll be working on the actual bones of the plane and I know that most of you guys will laugh since it may be a little too optimistic but then again, that's why it's up there. I'll also post some airfoils that we may use...right now, the airfoil on the plane is a 64-012 which is rather thick but it has a sharp enough LE to go into snaps. In any case, please download the file and make changes to it if you want or even start with the internals. This is something that we can really call our ship.


Butch

just added some sticks and sheets to the fuse. What do you guys think? The Sticks are .25 and the sheets are 1/8 and 1/16. You can download the plans at http://www.sharebigfile.com/file/739...R-0-1.dwg.html and is you want to add your input, please PM me so I can give you the ID and password.

So far, I'm thinking of a 1/8 balsa sheeting from the TE to the tail and 1/8 ply from the TE going forward. I am also thinking of a doubler to hold the wingt tube. The sticks are .25 in sq that will keep the shape of the lattice. I know it sounds very flimsy but I think the sheets and a a fiberglass skin would hold together well. What do you think?

You are overbuilding it for a 2M pattern plane. Look at the Black Magic and Insight threads for how to do the fuse. They use 1/8" contest balsa sheet only for the sides, with a doubler near the front. Mark Hunt told me he built one Insight with the doubler being 1/16" balsa, grain running vertically. No ply at all. And it was working fine. To anchor the wing tube, use lite ply donuts and epoxy them to the inside of the doubler. All the formers should be 1/8" contest balsa except the firewall and maybe the next one back. Diagonal sticks in the top of the fuse box instead of a top sheet are OK, and the turtledeck just covers them up when it goes on. Are you planning on using incidence adjusters? Then provision for mounting them with a couple of small pieces of lite ply must be made, as well.

What do the pattern guys think of making the box with truss sides and simply capping them with turtledeck and belly pan? No sheeting at all, just the open truss. Too light? Not stiff enough? Pretty much eliminates glassing the fuse for finshing, too, if you like that method...


Mark

dolanosa,

Any more progress on this one?


Mark

Mark,

Actually, yes. I haven't posted it up yet but I have considered your post and changed a whole bunch of items to the main design. After looking at some pics from many different pattern planes on the forum, I'm settling on a hybrid between the BM and some of the japanese roach designs. Basically, it will have less formers than the BM but it will have lightweight cross members. on the sides and top. The sheeting will be on the sides of the crutch like the BM. The main 'box' will be 4" instead of 5" so the motor will basically rest on a plate at the top of the box, doibled with triangle stock. I have also moved the wing 2" forward to give more tail moment and moved the horizontal lower so it is closer to the engine's CL. I'll try to post it tonight to the site sao you all can take a look. I will start putting in dimensions pretty soon. Thanks.

Butch

Here's the new iteration. Minimalist style. http://www.sharebigfile.com/file/965...-v0-2.dxf.html

Dumb question - can I get that file without registering?


Mark

Mark, PM'ed you with the registration.


B utch

Got it, thanks.


Mark

Hey Butch,

I had a look and it looks pretty good now. Things I see:

1) I would add in a couple of extra uprights in the tailcone end of the fuse sides to halve the distance the diagonal pieces are spanning. They sit at a pretty shallow angle now and I think they should be closer to 45 degrees. I wouldn't add extra formers, just the upright pieces in the sides and re-work the diagonals to suit.

2) The fuse is REALLY tall. To my eye, it seems too high, but much of that is simply esthetic. If I build one, I would change the canopy line just to suit my taste.

3) With that massive fuse, I would make the box deeper, at least 5" and probably 6" (it's 4" right now). This would be for better stiffness at little change in weight.

4) I would form the turtledecks and belly pans by sheeting foam cores. There is nothing lighter and it's pretty tough as well.

Keep up the good work!


Mark