Dowel construction?
 

Since it came up on Les' DVII thread, what are the tricks to constructing a fuselage with dowels?

RE: Dowel construction?
 

I would think the wire bracing would have to become functional, the joints would have to be tight with fishmouth joints, and the glue would need to be a good woodworking or better like epoxy.

RE: Dowel construction?
 

Proctor uses dowel construction on their EIII. I wonder whether it would be possible to rough glue the joints and then afterwards wrap each joint with fiberglass strips.

RE: Dowel construction?
 

Built a DVI with dowels and CA. no problem with nice tight joints.

RE: Dowel construction?
 

Hello There:

This My 1/3 Taylor-Craft Fuse. done with 3/8 Dowel Front done with 4130 steel tubing.
Very strong and lite used Cyno for all joints.

RE: Dowel construction?
 

Your Taylor-craft fuselage is very inspiring! I'm off to the store to pick up some doweling (both traditional and bamboo) for some experiments! :D

At tips on working with doweling?

RE: Dowel construction?
 

Very inspiring indeed! love the mianiature sawhorse looking thing that the tail is resting on.:)

RE: Dowel construction?
 

of course the gussets are a good idea also.

david

RE: Dowel construction?
 

Dowel construction is neat, I like it. Proctor's E-III is built with 5/16" dowel as Don mentioned, and a small 5-point brass fitting is pinned between the joint. Cables are then installed, and the structure gets very rigid.

Birch dowel is commonly used, but I prefer ramin dowel because it's about 1/2 the weight of birch, generally straighter, and easy to work with. The E-III has such a long tail moment that weight savings are important on that model. I'll use a formed maple dowel for the front lower longeron, and might possibly use balsa for some of the rear crossmembers and uprights. Proctor's method of cutting the dowel is cool; a jig is made where the dowel is slid in from the side, then a 5/16" brad-point drill is used from the top to make the cut. Clever.

John

RE: Dowel construction?
 

John, does the Proctor EIII have bracing cables running internally (from side to side) or just along the sides (and top and bottom)? Also I can't quite picture why a 5-point fitting would be needed.

BTW, I think I might finally get around to using that cowling you so kindly sent me several years ago when I was working on the EIII. It looks like there might be a DrI in my future. ;)

RE: Dowel construction?
 

"Birch dowel is commonly used, but I prefer ramin dowel because it's about 1/2 the weight of birch, generally straighter, and easy to work with."

Where does one obtain Ramin dowel? Thanks..........John

RE: Dowel construction?
 

Today I picked up some 3mm dowel made from Japanese cypress and some from bamboo. I was sure the bamboo doweling would be lighter but was surprised to discover that the cypress dowel was about 25% lighter than the bamboo. The bamboo is virtually shatter proof though. I also picked up some 3mm aluminum tubing that I could use for curved top formers. I'd like to be able to find some 3mm steel tubing that I could silver solder/braze into a framework forward of the CG.

PS. What IS ramin?

RE: Dowel construction?
 

easy trick for the fishmouth is to take a block and drill two 90 deg intersecting holes and use it as a drill jig. Dead end the dowel hole and depth is easy to gauge. attached is the DVI frame.

RE: Dowel construction?
 

Abufletcher,

ramin is the wood from a tropical tree (Philipines) named "Gonystylus" Lighter than birch but as tough and strong.

http://en.wikipedia.org/wiki/Gonystylus

Henner

RE: Dowel construction?
 

Henner, thanks for the link. But, the following quote is not particular encouraging:

"However, over-exploitation has led to all species of ramin being listed as endangered species, particularly in Indonesia and Malaysia. An estimated 90% of ramin in recent international trade is illegally logged."

RE: Dowel construction?
 

Dave, how did you do the bracing on your DVII?

RE: Dowel construction?
 

The hopps are annealed 3/32" Al tube and the bracing "wires" are metallic elastic beading cord. very convincing.

DJ

RE: Dowel construction?
 

Indeed. So you didn't, in fact, need the bracing to get a solid structure? Also I don't get why the "fish mouth" cut is necessary. Why not just a simple circular groove with a rat tail file?

RE: Dowel construction?
 

It would take you forever and you will never gat a tight fit

RE: Dowel construction?
 

I don't know. On my DrI experiment tonight I got one side done in about an hour and a half, but then I'm only using 3mm bamboo. The fit seems tight. Tomorrow I'll get the other side done and then put them together and then we'll see what kind of structure was possible with scale-size materials. I suspect, though, that I'll need functional bracing.

RE: Dowel construction?
 

Wow, I had no idea that Ramin was an endangered spieces!! It is commonly used in kite making, and that's where I usually get mine. Don, will be hard to describe the 5-point fitting, but would be very easy to see how it works IF I had a picture for you. Imagine a junction at the longeron, crossmember, and upright. 4 wires would be there, and a fifth would be your internal cross wire. Yes, the Proctor E-III does use these internal cross wires, very strong structure when completed, perhaps overbuilt.

John

RE: Dowel construction?
 

Hi Don. Here's a picture that might help.
Steve

RE: Dowel construction?
 

Thanks for the photo, Steve. I hadn't been thinking that there were wires making diagonals through each "cube" of the structure. That's an awful lot of wires! At the size I'm working with (1/6 scale) I don't think I'll try actual fittings. I like the idea (from someone here on RCU) of using kevlar cables except that kevlar isn't available here. I'm not shooting for the level of (internal) detail on Dave's DVII.

What kinds of jigs do you'all use to to keep your dowel fuselages straight and aligned during the process of putting the sides together? I'd like something that would hold the fuse halves in a rock solid position which I add the cross-members.

RE: Dowel construction?
 

Cocobear, can you explain to me the "fishmouth "construction you speak of. I like your DVI. Im currently building a GTM 1/3 DVI and I am also using dowels. I used dowels on my DR1 but didnt do the fishmouth that you speak of. I like your idea of the dril Jig but I do not think its necessary. My trip fuse is very strong however the Kevlar rigging was a must to keep it true and strong. I would like to see a better close up pic if you can :D
Glen

RE: Dowel construction?
 

Don, what works best for me when joining fuselage halves is to do it right over the top view on the plans. If that's not available, or it's a scratch build, etc., a centerline drawn on chart paper will do. Next, cut all of the crossmembers, and assuming the fuselage is supposed to be square, cut them in pairs. Make sure they are the same length!!! If one is a bit short, save it for the next shorter piece, and cut a new one. Then, get a set of squares together. They can be wood, styrofoam, shelf supports, old TV sets, anything that is 90 deg. They get fastened to your board, and you can use rubberbands or double sided tape to hold the fuselage halves while you are gluing. I'd do no more than two stations (4 crossmembers) at first, and let that set till the glue is dry. Then proceed with the rest.

I know I'm making this task sound like it's a big deal, and I apologise if I'm insulting anyone with basic stuff, but personally, I've always had a hard time getting a straight built-up fuselage, and this method works pretty well, peanut scale to 1/3 scale. Hope this helps!

John