I'm curious as to what your best method is for aligning the stabs and wing on a fiberglass fuse plane is. What's your method? Any pic's. I'm building a PAC Patriot with the "warped in the mold" Vertical stab that I've put off building for years because of it and am looking for a new and better way for maybe an alignment table. Oh, the stab is not plug in, either. Thanks for any replies in advance!!!!!!!!!! Chris

Here is a pic of the one that is on GW's site that I built. There is a stab fig for it also but I can't my pic of it. I think the site is GWair.com

Can you use that one with a rounded fuse?

I square the fin to my table surface first. The fin is your reference point for the horizontal stab and wings. They must be exactly perpendicular to the fin, so I take great care to ensure that the fuse is fixed in a position such that the fin is exactly perpendicular to my flat table surface. At the same time I also ensure that the thrust line is exactly parallel to the flat surface. Fin exactly perpendicular, and thrust line exactly parallel. With the fuse oriented in this way, I can ensure that 1) wings and stab are perpendicular to the fin, and 2) establish the incidence of both. To facilitate squaring the fin, I tack-glue the rudder post into the fin. Then I carefully mark the rudder post with a fine straight line exactly in the middle of the vertical length. This is not as easy as it might seem. The fin may not be perfectly symmetrical (not even the good European kits are perfectly symetrical without defects). In your case you have a curvy fin. You will need to do the best that you can. This fine, straight line on your rudder post is the reference that must be perpendicular to your flat table.

If you do not have a flat table -- really flat, then you will need to consider some other method. I have a granite surface plate that is flat to within 0.0004 of an inch across the entire surface. That is not absolutely necessary, but it makes me feel good. Most things are not flat. You might think they are flat, but they are not. Doors, inexpensive aluminum straight edges, floors -- you name it, they are curvy. Even pool table slates are not very flat. Some are, but most are not. If you use those type of things as references, then you will probably not produce a straight airplane. Most doors for example are often off 1/8 inch or greater across the surface area. The whole door might twist, dip and rise. If you are using a non-flat surface as your reference for wings and stabs, your measurements will be off, and your plane will not be dead nuts straight. You can try to build a flat surface, but it is not very easy, and it may not stay flat for long.

Next I install the stab. I use a surface height gage to inspect the level of the stab in various locations. The bottom at the tips, the trailing and leading edges at the tip and roots. The goal is to get your stab mounted such that it is exactly parallel to the building surface, with the correct incidence on each stab half, and perpendicular to the centerline of the fuse. You can check this last measurement by triangulating the length from the stab tips to a point in the center of the fuse near the nose.

Then I install the wing using the same procedures and measurements. If it is a one-piece wing, do not assume the saddle is exactly perpendicular to the fin. That means you may have to do something to correct the offset. Personally, I prefer plug in wings. This is one of the reasons. I do not reference my wing installation from the tube itself. The tube may fit into the wing slightly crooked. If this is the case, and you install your wing tube perfectly aligned, then your wing will end up not perfectly aligned. Same story for the stab. If you glued the tube sockets in yourself using a very careful procedure on a flat surface, and you know that the tube is dead centered in your wings/stab, OK then you could align your tube with respect to your flat surface. But I like to measure the wings and stab, and not the tubes.

How long does this take? It usually takes me a several days to align and mount the wings and stabs. I do not stop measuring until every possible measurement is within 1/64th of an inch. If you move one thing, something else changes. If you bump something, then you have to recheck all measurements. I don't mix epoxy until I am dead certain it is straight. But once it is done, you should not have to repeat the process until your next airplane.

Everything that I know I learned from somebody else. If there is an abbreviated set of steps that achieves superior accuracy, I would like to learn about it. I continue to learn new techniques by talking to other builders.


Regards,

David

Hi
If it is still available Bob Noll ( Absolute accuracy series) did an excellent video on aligning a pattern plane.
Goes through the whole process step by step including making sure your surface is absolutely true.
It is a shame he didnt do more they really were very very good videos.

Mike

First, with a heat gun, you can straighten out some or all of the curve on a fiberglass fuse. I don't go to the extreme care of some, Because I figure some of it cancels out in the air ie: slightly different airfoils, leading edge radius, wing weight, wing area, aileron area, it all varies side to side, as these planes are hand built. If your within +/- 1/16 or 1/8 on squareness, I'll guarantee you cannot tell in the air. I use my pool table and I have four vernier stands. So I use one to make the stab perpendicular to the table. Then I set the elevator on two stands, one on each end to hold it level, THen, I walk to the end of the room to see if it looks right. It's easy to make a mistake measuring, but if you'll look straight down the front of the plane, you can tell if the elevator and rudder are perpendicular to each other. Actualy on this and on the wing to stab relationship, visual can be almost dead nts. Anyway, I then epoxy the fin to the fuse and let it sit overnight. I do the same with the wing. If it's two piece, I slip the wings on and align, not just align the wingtube, because sometimes I find the wing tube is not identical on both wings.

Hello David,

Could you describe your granite surface more? ie. size and how is it supported?

I/m a simpleton on this.

I hang a joy bubble from the Vertical stab, on the rear and align the fuse up and down so the vertical stab is vertical. Stabilize the fuse with whatever I have avail(fuel jug, landing gear blocked up etc etc.)

Place the wing tube and socket with lite ply donuts using my incedence meter across the fuse, ensuring the wing tube is straight 90 degrees to the stab. I actually like the bubble on the the incedence meter better than the measurement. Use a string or tape measure to move the tube front to back to get it staight that way.

Lastly, I use eye sight to glue the stab tube(adjustable stab) in, in respect to the wing tube. Stand back about 10 feet and you can see when perfect alignment to the wings or wing tube is achieved. Use string or tape measure to make sure it is straight fore and aft.

I use adjusters on both the stab and wing so getting the incidence correct is not crucial as it can be adjusted during final assembly, as long as it is in the ball park.

Ed

Sure.

This is a 36"x48", 6" thick tool grade B black granite surface plate made by Precision Granite Co, Whittier California. I purchased it directly from Precision Granite. They also manufactured a custom 48"x24"x2" piece that I use when sheeting wings. I believe that it weighs about 2000 pounds or a ton. For its size, it is very heavy. It sits on a steel stand that has steel castor wheels. I can easily move it around in my garage. The stand incorporates three 3/4" threaded bolts. The surface plate sits on top of these three bolts. I am told that this is the optimal way to support a surface plate.

I will post some pictures tomorrow when it is light.

The cost of a surface plate is not bad considering that it is an awesome tool. The total cost of the surface plate plus stand with castors was $1000 -- brand new, and traceable to National Institute of Standards of Technology. I paid another $100 for the smaller piece, and the guy at Precision Granite delivered it to my home. I had to rent a fork lift, but he operated it and placed the table just right on the three bolts.

I use it for all types of purposes that require a very flat surface. You can load it with a lot of weight, and it stays flat.

The story on these tables is that they mine huge pieces of granite rock from a location near Yosemite Nat. Park. They put one rock on a flatbed semi and haul it to Whittier. There, they have a 100 yard long rock saw made out of steel cable. The cable is driven across a pulley, and that slices the rock into slabs. Each of these slabs is then carefully and painstakenly machined by huge diamond disks. This gets the surface fairly flat, but it takes a long time, and they must change the sanding material frequently. I am told that it is very expensive. The slab is now mostly flat, and the edges are incredibly sharp and dangerous. They chamfer the edges, but the guy told me that he has seen several accidents and some lossed fingers during handling of the slab. Next, the surface must be flattened by hand, down to very close tolerances. This is also a very long process, which is why they are expensive. The bigger the table, the more money and weight. He says that he makes his big money by selling to Integrated Chip manufacturers.

I got a 48"x36"x4" granite plate from Enco. Perpetually on sale for $239. They claim it's flat to .0004", but not N.I.S.T. traceable. Even if it's only half as good as they say it's more than good enough for pattern workshop use.

This is the same plate MSC sells for $826. MSC owns Enco. It ships from the same warehouse and even comes with an MSC label. Shipping costs are not insignificant and I paid an extra $50 for lift gate service.

I welded a stout stand from scrap steel, cost about $20. Quality name brand casters are a must.

http://www.use-enco.com/CGI/INPDFF?P...&PARTPG=INLMPA

http://www.mscdirect.com/PDF.process...ection_Id=1504

Well, I have a pretty darn straight and level building table. It's a super heavy duty base cabinet that weighs a ton. It's very straight and level. I checked it with my rotary laser. I was looking for the best way to secure a pattern fuse to the table. It seems the old weights and stuff always have worked for me, but it takes for ever as I always knock the plane one way or the other. I really need to just order the video. But thanks alot for all of your great advice. I will take it all into consideration. Good flying, Chris

You could build a type of stand that has adjustable feet, secure balsa pieces to the stand that conform to the bottom of the fuse, and then tack glue the balsa cradle to the fuse. I have done that before, and it was too much work. The last plane I built I used sand bags. The sand or shot does not settle much unless you try to deform it. When I have everything just right, I use masking tape to secure the fuse from movement. I drape the tape over the top of the fuse and onto the table without deforming the fuse. Several pieces of tape will keep the fuse from moving until you are done.

If you find a better method, please share.

David

Hi Jeff

Where do you fly in the Columbus area? I get down that way twice a year at Thanksgiving and Memorial Day and might have time to at least come out and watch. I'm from the Twin Cities area in Minnesota -- my Dad lives east of Reddington, so I drive down that way from the Indy airport.

Look forward to your reply,
Tom

Gerald Williams (GW) had a great, all metal alignment jig on his webiste. (gwair.com) I intended to build one, but his website is down and I haven't been able to contact him. He was a moderator of this forum. Anyone know where else the instructions for building this jig might be posted and/or how to contact Gerald?

I have the photos from the jig I built if anyone wants them or can post them on a web site again. . .

Most of the photos are also in the "2M Plans" thread somewhere in this forum.

interesting, if you could post them, that would be awesome. Thanks alot. Well no need to post I looked em up and all i can say is WOW!!!!!!!!!!!!! Not that's quite the setup and I will be building one within the next couple of weeks. Thanks alot!!!!!!!!! Chris

Here is the link to the photos and info on the jig in the 2 meter plans thread. I forgot they were there! I think this link will bring you directly to page eight of the thread where the info is. Thanks Keith.

http://www.rcuniverse.com/forum/m_41...y_meter/tm.htm