building without hold downs
 

has anyone ever tried to build an airplane without any kind of hold down mechanism?

no t-pins, magnets, etc..

just straight flat surface with plan underneath of wax paper

Yes,...
 

Quite often these lazer cut pieces lock together very nicely, and as such are glued in place. I've found that a rounded fuselage can be put together easier and more accurate if assembled and glued off the table. Just be sure to build over the plans so that bulkheads, etc. are located properly. Sometimes a wing will require a "washout" former to be pinned to the plans (and table) to give the ribs their proper angle prior to glueing.

Roger

building without hold downs
 

I think you will find that SOME SORT of holding method is IMPORTANT. Before my new table, I simply used masking tape and/or weights. Measured and checked eveything 4 times before applying glue. My new table allows the use of magnets in a bit diiferent way....see attached picture.


As long as the table you are building on is TRUE, your parts will be too.

building without hold downs
 

im did have in mind using weights in certain places that make sense to use them, just like in your picture, makes sense.. but im wondering if anyones built wings without anykind of hold down mechanism, rogerswin brought up the point about wings with washout tabs, that seems like it could bring up some trouble

id just like to hold the wing rib true, drop some CA and move on to the next rib

building without hold downs
 

I haven't used pins or weights in over 25 years.

building without hold downs
 

do you use one of those magnet boards?

what do you use to hold things at right angles while glue sets?

i can imagine building most of a airframe fine without pins but id still use wieghts and still having doubts about building wings, guess ill have to try it with a Edge 540 profile i have sitting here

Freebuilding
 

I build all my models without pinning them or weighing them down. For wing, I will lay the spars on the plans, mark the locations of the ribs, remove the plans and start gluing on the ribs. I check each rib as I glue it so that it is square to the table and square to the spar. As I glue on the leading and trailing edges, I make sure I have everything lined up as I glue. Then I will glue on the sheeting on one side. After the sheeting is on I will remove the wing from the table to sight down the wing to look for an twist or anything. I will check it for the proper washout and then put it back on the board. I will place a block under the tip to get the proper washout and add the sheeting on the other side.

What this allows me to do is get the right washout without a hassle. I got sick and tired of pinning or weighing the wing down, gluing everything together, pulling the weight off or pins out and having the wing warp or twist. If I have too much washout before I put the last of the sheeting on, I will block it so that it don't have enough washout on the table. After the last of the sheeting is added, the wing will normally have the right amount of washout. If it doesn't have enough washout, I will block it on the table so that it has too much, add the sheeting and it corrects itself. I have never had a wing more than 1 degree off.

Fuselage are built in the same manner. As long as I check for proper alignment and square everything up at each stage of building, it will come out as close to perfect as I can build. I have found throughout the years that I can build a lot quicker this way and I don't have to worry about gluing the parts to the table. This method works great for me, but I know a lot of local guys around here can't beleive any of my stuff comes out straight.

building without hold downs
 

Quite often, bowed spars, die-cut ply fuse sides, etc. MUST be held straight somehow until structural members are glued in place to hold it all straight.

Pins??????????
 

The only time I use a pin is when I get a splinter; and that doesn't always work as well as a #11 blade.

I prefer to use wax paper and 3M77 spray. The sprayed glue goes directly on the plans (copied plans), which are then covered with wax paper. A small amount of 3M77 is then sprayed on the fuse/spare/tail-feathers/etc... and positioned on top of the wax paper.

When done, the excess glue sands off easily, and the plans have a subtle tackiness that allow them to be rolled up without the need of a rubber band to secure them.

Works for me ;)

building without hold downs
 

Like F4U, I hold the pieces and glue them as I go. I do build over the plan with wax paper most of the times. I once built a gentle lady on a friday night because I ruined my contest 2M bird and flew it sat and sun in the contest. Actually still have it. Never placed less than third with it. Had a bet with a friend and built an electra wing in an hour ready to cover.

Takes friends months to build something like a bigstik. I built one in 2 weeks from scratch and it is as nice as any at the field. I guess we all build like we were taught. The guy that taught me when I was 12 was a columbian nation champ. He was very quick and a perfectionist. Built some of the best looking stuff I ever saw. What a pilot!

building without hold downs
 

thanks for the info guys, im going to build my next plane OMP Edge 540 without pins, if that goes well ill build a discus launched glider next too

Pins??
 

Just started building my first kit in ten years and I never even thought of pinning it down, You must try and gain experience in order to develope a style that works good for you but pinning is not always nessassary. Also every kit is different so tecniques that work on some will not work on others.

building without hold downs
 

I am at the moment building the wing of a small electric model and even though so for it has only ....9 peices it has close to 40 pins in it holding it all true...as you can see, i'm a little bit of a pin freak.

building without hold downs
 

I have always used pins and that comes from building planes with very slow drying glue, way before we had Ca and epoxy. I'm comfortable with this method and did try a jig once but found out that I could frame a wing faster my way then I could using a jig. I just guess it comes down to how you learned how to build and what you're comfortable with.

building without hold downs
 

I like to design my small planes to build straight so I can build in my lap while in a recliner watching TV. Of course I do have some advantage there in tooling. My scale birds I build on 1/2" glass.
If you have an eye for straightness you might get away from the table top some of the time. I advise most to find what works for you and do it; it saves you from needing anti-acid. There are a million modelers that do the same thing 1000 different ways. Some of those ways make for a beautiful flight and the others make for some great crash video. It makes for a simple means of measuring your success. Of course for kits you could always try and follow the instructions. I must admit though that I have yet to succeed in that venture.

citabria wing
 

this is my first wing in 7 years, no pins at all. Mostly built on a glass table for true flat surface but a lot of it was in mt chair watching T.V. and it seems to be very straight.

lotta slop
 

lots of slop in this kit (SIG Citabria) as you can see in the gaps at the spar and the same thing with sheet balsa over ribs but the wing still came out straight so far.
Can be done but you must be pretty sure of your building ability.