The Fuselage is Tack Welded

The fuselage is out of the jig! Dale Doane tacked welded the main portion of the fuse yesterday. After I fab the finger plates and other fuselage attachments, I will take the fuse to Dale's shop in Newnan, GA to complete the welding. I continue to be impressed by the VR3 tubing kit. The tube which extends rearward from the bottom center of the firewall looks crooked because it is! This is where we ran out of Argon and that particular tube is still loose.

Just so happens that Glenn Bridges got his VR3 fuse tack welded and out of the jig the same day!

Prepping Fuselage for Welding

I disassembled the fuselage and polished all of the weld areas this week. Acetone was used to clean the weld areas inside and out to remove oil contamination. I am a little concerned that oil contamination may migrate from the interior of some of the tubes, especially the ones in vertical orientation.

I have arranged with Dale Doane, an A&P who works for Delta to weld my fuselage. Dale plans to fly his Cessena from Atlanta and tack weld the fuse here in my shop. I will then take the fuse in my truck to his shop in Atlanta for finish welding. We had hoped to get started this week but now it looks like the weather isn't going to cooperate.

Glenn Bridges has his VR3 fuse all jigged and polished and started tack welding today. looks like he will be ahead of me for a while!

Center Section Spacers

Made a couple of sets of spacers for the center section today. The .115" and .300" spacers were too short to easily make from the purchased spacers so I made them from scratch using bar stock. The .250" long spacers were purchased from www.aluminum-spacers.com.

Next will be the 1"x 1" x 1/8" "C" channel fittings for the ends of the compression struts.

Rib to Leading Edge Clips

Made 70 angle clips to attach the ribs to the
leading edge tubes today. I taped 7 or 8 clips together and
"gang" bent them as a group to save time. The bender is so accurate I was able to adjust for the added thickness of the tape so the bends would come out exactly right.






I had to push the holes outward toward the ends of the
angle legs a little. As drawn, there is not sufficient room for
a rivet puller to operate. The drawing
references " 4 number 3 rivets". The rivets which go in
the tube must of course be pulled rivets.

Compression Strut Bushings

Tom and I made two sets of bushings for the ends of the compression struts last week. We started with 3/4"x 3/4" x 5/16"ID spacers from http://www.aluminum-spacers.com/. We made a mandrel for the lathe so we could turn down the barrel of the spacer to 0.652" leaving a 0.060" flange at one end

The bushings fit nicely in the 3/4"x 0.058 wall x 6061 tubes. The "hammered" effect on the ends of the bushings is from tumbling the parts after the spacers were made.

Priming the Spars

We had some nice weather (70 degrees) earlier this week so Tom helped me prime the spars for one wing. First we pulled all of the spar caps and webs over a 3-M wheel to polish all the edges smooth Then we scuffed every thing good with Scotch-Brite and cleand with a degreasing cleaner.

We are using RM brand DE15 epoxy primer and it seems to work very well. I used PPG DP40LF on my RV7A but that paint store closed. (Edit: See updated post as I have reverted to DP40LF)

The three cans in the picture......$335.45 +tax Ouch!

P.S. The funky looking parts near Tom's left hand are wing root strakes for our RV-8. They are reported to lower the stall speed significantly and eliminate a strong tail buffet which occurs near stall speed.

Bending Rib-to-spar clips

Bent the rib-to-spar clips for one wing today.

The following pictures show a clip in the process of being bent.

The first in the sequence shows part in position.

The second shows the ram just touching the part which is "zero".

The third shows the part at 0.210" ram travel after zero. This will result in a part with 82.8 degrees included angle.

The fourth is the finished set for one wing.

Teardrop Aluminum Strut Material

I found a source for teardrop aluminum strut material. It is:

David Gordon
AED Motorsport Products 5373 West 86th Street Indianapolis, Indiana 46268 USA Phone: 317-334-0569 / US Toll-free 888-413-0233 Fax: 317-879-9397

email: dave@aedmotorsport.com

or web site: www.aedmotorsports.com

They offer teardrop tubing made fro 1.5" x 0.058" wall 6061-T6 per the Skyote plans. They custom make this to order so they only deal in 12' lengths. The best deal is to order three 12' lengths which will make struts for two airplanes with one strut to spare.

Drilling First Main Spar

Tom and I drilled the first spar last Friday the 14th. We proceeded with extra care as it was the first spar to be drilled using the laser cut spar drill/assembly jig. We drilled all of the holes for the ribs and fittings in about 50 minutes. We did not drill any holes in the tapered section of the tip.

Everything worked as planned. We will drill an aft spar next. We plan to complete the rib/fitting/spar assembly for one wing before drilling the remaining spars. Better safe than sorry.

Excellent Fuselage Construction Book

As a neophyte fuselage builder, I have found the book "Construction of Tubular Steel Fuselages" by David Russo to be very helpful. Much of the information in this book directly transfers to the building of a VR3 fuselage. The book can be found here: http://www.actechbooks.com/construction_tubular_steel.htm

VR3 Final Report

I am happy to report that the final version of the VR3 Skyote fuselage tube kit has been assembled and checked. I received the replacement longeron and firewall tubes last week but just got around to assembling them yesterday. These tubes have a different arrangement for the joint between the longerons and the firewall tubes. The new joint arrangement provides the same type of interface with the landing gear and flying wire fittings as called for on the plans. The original joint design from VR3 was not wrong, just different.
The new joint design provides the same "perch" for the fittings, but eliminates the need for plugging the end of the longeron tube by mitering it to the vertical firewall tube. Since a picture is worth a thousand words, just take a look at the latest posting in the VR3 photo album. Others may take issue, but I am satisfied that the new joint is structurally equivalent to Pete's design while being easier and more accurate to build.
I am very happy with the VR3 kit. I have had a couple of experienced tube fuse builders look at it and they said that it would not be possible for them to duplicate the accuracy and fit quality using the traditional manual profiling methods.
The VR3 kit is about the same cost as Pete Bartoe's rib kit. In my opinion, the VR3 is at least, if not more of a time saver, than the rib kit. I think I could eventually hammer out the ribs if I had to. I'm not sure that I would ever get the fuse hand fitted to a point that would make me happy.
In my book, there are only two valid reasons not to go with the VR3 kit:
(1) You WANT to fit the tubes yourself.
(2) You can't justify the $$.
If you are not burdened by either of the above "problems" then VR3 is the way to go.
In conclusion, I have no connection with VR3, financial or otherwise.

Aluminum Spacers

I just received the first aluminum wing fitting spacers.

I got them from http://www.aluminum-spacers.com/ . In a quantity of 500 they were only $0.17 each. These are 1/2"dia. x 5/16"bore x 3/8" long. I wil make the shorter spacers by cutting down some of these.

The spacers are a perfect fit with the 5/16" 4130 tubing which will be used to make the bushings that fit inside.

The actual company name is Daven Screw Machine Co.. They are a small family run business and were very easy to deal with. If you don't see what you need on the web site, give them a call as some standard sizes are not listed as was the case for the above spacers.

Spar Drill/Assembly Jigs

I got the spar drill/assembly jigs from the laser cutter yesterday. They will allow all of the holes to be drilled in all five spar components as an assembly. No layout of individual holes will be required. Maybe I will have time to give them a trial run over the weekend. There are approxomately 134 holes in each spar assembly. Multiply that by eight spars and that's a lot of holes!

The spar jigs were laser cut while the wing fittings were cut by waterjet yet the holes match perfectly.

I built a flat table using MDF. It has a spline to hold spar flat. All of the hole locations for ribs and fittings are in the jig. No layout necessary!

Radius Bender

A while back I sketched up a precision radius bender. I based it on some Thompson Linear Ball Bushings which were surplus from some project long past.

My friend and fellow RV builder, Les Kanna, finished building the radius bender today. I decided to bend a few fittings and I am happy to say it works great!

The bender features a micrometer adjustable stop which precisely sets the bend centerline under the radius bar. The distance from the bend center to the edge of the part is given by the CAD program. I am using a 20 ton hydraulic press from Harbor Freight.

It produces a nice smooth bend of the correct radius. The bender is currently set up for a 0.125" bend radius

Fittings Cut by Waterjet

I received the first batch of wing fittings about two weeks ago.

The quality is excellent.

VR3 Kit Assembly Completed

I was able to complete the test assembly of Skyote VR3 kit #001 yesterday (Nov. 21). The tubes all assembled as advertised with no visible gaps. VR3 will be replacing the longeron tubes and the firewall perimeter tubes so that the longeron/firewall joint will better conform to Bartoe's drawing. The change in the joint arrangement will allow the fittings for landing gear struts and flying wires to interface with the longeron tubes as originally intended.

The VR3 Kit is an incredible time saver. I'm not sure that I would ever be able to fit the tubes in the traditional manner. I know that I could never match the quality of the work!

New style Assembly Jig

I decided to redesign the assembly jig for better accuracy and better access to the tubes. The new jig is an internal structure as opposed to the external structure of the previous jig. The stability and accuracy is much better as well as better access to the tubes. Each tubular crossmember is supported by a pedestal which locates it in the correct dimension in all dimensions. The longerons are added next followed by the diagonals. The VR3 tubes don't actually need this much jigging for welding, but my intent here is two-fold. I want to confirm that the tubes conform to Bartoe's drawings as well as confirm that the fit each other properly.

Fuselage Progress

I was able to put in about 7 hours during the past week. The progress is apparent in the photos. The fit of the tubes is excellent. There is really no "fitting" to do at all. All of my time is spent building the assembly jig to hold the tubes in the correct position. Absolutely no grinding or cutting tubes required.

I am not satisfied with the stability of the jig. The tall 2x4 posts are relatively easy to deflect at the top end. If I add gusset bracing it will obstruct access to the tubes.

Trial Fitting Fuselage Tubes

I decided to purchase a CNC profiled tubing kit from VR3 in Canada. Since this was to be the first Skyote kit produced by VR3 there was some design time involved. I placed the order on 9/09/07 and received the complete kit around 10/27/07. Subsequent kits should have a shorter delivery time. As purchaser of Skyote Kit #001 it falls to me to perform the initial check-out of the tubes to confirm that they all fit well and conform to Mr. Bartoe's drawings. The tubes will need to be assembled in 3-D without welding as some of them may need to be modified. This means that the assembly jig will likely be a little more elaborate than what will be required to assemble and weld subsequent tube kits.

The Fuselage Assembly Table was completed on the afternoon of Nov. 2 so we took a shot at assembling a few tubes starting at the firewall. The tubes all fit perfectly. Unfortunately the design of the joint between the firewall tubes and the longerons does not agree with the Skyote Drawings. As supplied, the longeron tubes butt into the firewall tubes which are mitered to each other. The Skyote drawings call for the longerons to extend through and be flush with the forward surface of the firewall tubes. This allows the firewall tubes to butt into the longerons. I spoke to Don VanRaay of VR3 about this discrepancy and he readily agreed to supply replacement tubes per the drawings. We agreed to wait until all of the remaining tubes have been fitted before replacing the tubes in question so that all of the tubes can be corrected at once.