As usual, we will be publishing a calendar of events in the next few issues. If you have any events you would like listed, please let me know well in advance. Watch for further listings in the next newsletter.
Here is a great opportunity for those of you who are starting or thinking of starting an RV project and want to know what it will require of you. Mike Talley has agreed to have a project visit of his RV-6 project at his home in Arlington.
Mike has his tail done and is currently working on his wing structure.
Even if you are not building an RV-6, this is a great opportunity to meet other builders and discuss building techniques that can be used on all models. For those already flying, come and share your experiences with our fellow builders.
Plan on arriving at 11am on Saturday, January 25th. The address is 4427 226th Pl NE, Arlington 98223, phone is 360-435-2130. Driving directions: exit I5 at exit 210 (236th St), go east about 1.5 miles to the first stop sign at 35th Ave, turn right into Eagle Ridge to the second street, 40th Dr, right on 40th to the stop sign, at the stop sign turn right on 226th Pl NE. Mike is the first drive way on the right. There is a tree in the front with two signs "4427" and "105". Mike's shop is behind the house on the left of the driveway.
As usual, we plan to have a few fly-in events. The first for this year will be at Tacoma Narrows Airport Restaurant on March 22 at 11:30am (Saturday). As in the past, this is an un- coordinated social event and all are welcome. Remember, if you are driving in, watch the weather. The event is automatically canceled if the weather is bad. Please don't try flying in in bad weather.
If you have any suggestions for other lunche flights, let me know prior to the March issue and we will get the word out.
Here is a list of the current officers of the Puget Sound RVators. They need your input on how you want things to be run. What events should we have? What should our dues be for the coming year? Give them a call with your thoughts.
Sealing the fuel tanks of the RV series of airplanes is often considered to be one of the most difficult and certainly the messiest jobs of the whole project. It is also something that most builders approach with some degree of trepidation, as the materials and processes are new to most people and the results of a sealing failure are unpleasant to say the least. Going back and trying to "fix" things is never fun, especially when your new bird is gassed up for the first time and feeling that urge to make the initial flight.
RV tanks use the tried and true method of internally fuel sealed wing structure. This is a commonly used method in the fabrication of general aviation aircraft, commercial jetliners, and some military fighter planes. The techniques used that are described in the builders manual are basically the same as those used by a large company like Boeing. Obviously the specific applications are somewhat more simple in the RV as we have that nice straight forward "build it at home" design. There are not too many decisions to be made regarding how to seal RV tanks. Most people just follow the directions, use that black sticky stuff that Vans supplies, and do a pretty darn good job of it. If they have a few small leaks, they fix them when they occur during pressure test, after the tanks are first filled, or more infrequently after the plane has been flown a while. One of the few decisions that does have to be made is whether or not to slosh the tanks after they have been assembled and the primary fuel seal is complete. This is a process that involves putting a special thin sealing material, known as sloshing compound, in the tank and "sloshing" it around allowing it to penetrate any pin holes or other small leaks that may exist in the primary seal. When it cures out it seals the pinholes and hopefully the tank. This method was the baseline approach for years in the RV world where the "tank sealers" were not only uncertified, but totally inexperienced.
Over the years there has been quite a bit of discussion with people weighing in on both sides as to whether this "belt and suspenders" approach to a tank sealing is the best way. There have been a few well publicized cases of the sloshing compound coming loose from the inside of the tank in what amounted to small sheets of the material that subsequently plugged or restricted the fuel system resulting in a power failure. It was mainly for this reason that I decided to seal my tanks only with the primary seal and count on it to work.
The following are some information and tips that I picked up in my work at Boeing that I feel are relevant to the job of RV fuel tank sealing.
First, is a basic understanding of that black sticky stuff that Vans sends us. It is the product of a variety of companies that meets the MIL-S-8802E specification (sealing compound, temperature resistant, integral fuel tanks and fuel cell cavities, high adhesion). It is commonly known as Pro-Seal, the identical product is produced by both Chemseal and Courtalds (which is right here in the Puget Sound area). What we actually get from Vans is MIL-S-8802E, TYPE II, CLASS B-2 which can be deciphered with the following information:
Second, is the technique of using the Class A material to brush coat all of the sealed areas to ensure that the pinholes that may exist are all filled. After I had completed the sealing as described in the builders manual and before riveting on the back baffle, I brush coated a smooth layer of CLASS A- 2 sealant over all of the internal sealed areas including the rivets on the inside of the fuel tank rib flanges, the tank end rib penetrations, and all of the fittings on the tank vent and fuel feed lines. After riveting on the back baffle I brush coated all of the exposed sealed areas on both the end ribs and the baffle and baffle rivets.
I pressure tested my tanks with the balloon and air leak down method and was pleased to find there were no leaks. I now have about 6 months and 45 hours on my RV-6 and have almost forgotten what a nasty job sealing those tanks was!!
MIL-S-8802 sealant can be purchased in pre measured semkits from Aircraft Spruce, and American Avionics on Boeing Field. Courtalds in Kirkland can provide all kinds of technical product literature and may sell you a small non-commercial quantity if you ask them nicely.
Walt Cannon
524-7221
WCannon313@aol.com
This is the time of year when our board members get together to discuss the up-coming year and set dues. Please hold off on paying dues until the new amount is announced in the next issue. There is a good chance dues will be lower for the next year.
I have noticed that if a business or organization has a phone number they probably have a fax number and if they have a fax number chances are they also have a Web Page. I guess this is a sign of the 90s.
I thought it would be nice to try a web page for our group, so here it is: www.geocities.com/CapeCanaveral/7421. Sorry about the long address and the different kind of name, but that is what I was given. I am new at programming in the HTML Code but I will continue to improve on the information and format of our web page. Please visit the site and give me your feedback, just click on my E-mail address at the bottom of the web page.
Check out the Members Section on our web page and you will see what data I am publishing. Your data will not be listed unless I receive your authorization.
You will also find a calendar of Events for 1997 on our WEB page. I will be adding activities, airshows, and fly-ins as I learn about them. There are also some good links to other sites. Oh, by the way "Bookmarking" our site helps for future access. I look forward to hear from you. Have Fun.
As a result of the "organizational meeting" that was held a Thun Field last March, we (the members) decided to designate an individual to be the keeper of whatever Club materials existed, to loan out for others to use. To make an otherwise interesting story short, I (Dan Thomas) got/volunteered for the job. I should have put something in the newsletter a long time ago but just never got around to it (ed: you know how builders are).
We have the following items available to loan to members:
1. RV-6A wing construction video tapes, by George and Becki Orndorff.
2. RV-6A fuselage construction video tapes by the Orndorff's.
3. Scales for doing weight and balance of RV aircraft.
4. Instrument hole knockout tool - standard 3 1/8 and 2 1/4" round sizes.
5. Empenage skin clamps - made of wood to hold skins to frame.
6. Landing light lens mold - to make lens from raw materials.
7. Rudder cable exit fairing mold - to make fairing from scrap aluminum.
8. Clamp- used to position and hold wing ribs on main spar and drill .063 reinforce angle.
9. Hole locator for 3/4 X 3/4 X 1/8 thick angle longeron (1" space, etc,)
The first four items were purchased with club fund. Items 5 through 9 were crafted and donated by Carl Helland. Thanks Carl. If anyone knows of something I left out or wants to donate some clever item they made, give me a call. To borrow items, call me at (206) 353-2659. My address is 7202 6th Ave W., Everett, WA 98203. I live about 2 miles east of the Boeing Everett plant and I have a hanger at the Arlington Municipal airport.
Currently our club could afford to increase our inventory of loanable items, as long as the item is not to expensive. If anyone has a suggestion for a loan out tool, please let me know and our board will consider it. One item we have talked about is a fresh air painting mask. I am afraid that a pneumatic rivet squeezer is a little to much, especially one for 3/16" rivets. Hopefully this will get you thinking.
While we don't enjoy the extreme cold temperatures of the midwest, I have noticed the increase of my engine oil's viscosity, even at 40 degrees. Aircraft oil heaters can cost one hundred dollars and up. By using a heated dipstick from an auto parts store, you can easily build one for ten dollars.
Since most Lycoming oil filler tubes are constructed of plastic, I used a scrap piece of 1/2" aluminum tubing, cut 1/2" longer than the plastic oil filler tube. By centering the heated dipstick inside this tube, you will prevent it from melting your filler tube. I also installed two 90 degree brackets at the top to prevent the shield from sliding into the oil sump.
This heater needs about 30 minutes to warm the oil and I wait a few minutes after un- plugging before removal. This allows the unprotected end to cool. (See Picture in Newsletter)
After flying my RV-4 for many years with the stock tail wheel supplied with the kit, I recently changed. My wife surprised me with a new full swivel unit, from Van's, for my birthday.
Installation was an easy task, thanks to Carl Helland. He made quick work of cutting the end off my old tail wheel spring and turning it on his lathe to the required diameter. This was the preferred method for me as I did not want to use a new spring. This would have required matching the spring mounting bolt hole with the existing structure. The installation turned out to be straight forward and the most timely task was waiting for the paint to dry. The biggest advantage, as I see it, is not getting my leg greasy when I pick up the tail to move the plane backwards. Also an advantage is the fact that this unit has more clearance than the stock unit (But I wish it had even more). I was always catching the aft lower tip of the tail wheel spring on rocks, etc. The new unit is a bit better in this area, although not as good as some after market units.
Speaking of after market units, Although superior in ground clearance, I chose not to use one as they raise the tail somewhat. With Van's new unit the three point attitude is unchanged from the stock configuration. This may not be a problem with the newer (longer) gear legs on later RV-4 kits.
For those that have not yet discovered it, Boeing Surplus has a lot to offer plane builders, especially those trying to build a plane on a budget. In this article we will examine what is available at Boeing Surplus. Before we jump into the details about what is available, lets make sure you can find the place. Being a surplus outlet, you are not going to find a golden "B" to direct you to the store. The store is located on the corner of S. 208th and 84th S. in Kent, Washington. Their phone number is 206-393-4060.
The store is broken into three major sections. The first area is about the size of a medium grocery store. This section contains the bulk of the small surplus items which are sorted into bins. You can also find electrical wire as well as fabric in this area. The second area contains used furniture as well as the world famous "Tool Crib". The last section is a large outdoor area containing the surplus aluminum, steel, titanium, and other weather tolerant items.
Now, to justify the trip there had better be some good bargains. Sure enough, especially for those who have not yet stocked their shop, there are more than enough bargains to justify the trip. Even for those who are well into construction, the outlet has plenty of bargains.
Here are a few examples of what you may find and about what you will pay. Keep in mind however that this is a surplus outlet and items can change daily. Also, if you work at Boeing remember to bring your Boeing Badge as it will get you a discount.
WIRE: It runs about a dollar a pound (instead of the 25 cents a foot) for Tefzel coated aviation quality wire. They always have plenty of quantity but the selection is hit or miss. Small 22-28 gauge wire is generally available in a variety of colors and coatings. 10-20 gauge wire is usually available but in a more limited selection. Some wire is not aviation quality. Remember that this outlet is for all of Boeing, including their facilities areas. Some of the wire is for telephones or factory AC wiring. It's usually easy to tell the aviation quality by the markings on the spool ends and the marking on the wire itself.
BUCKING BARS: Hit or miss on selection, but generally they have a good variety of shapes and sizes. We've bought all but one of our bucking bars here. Prices are in the $1 to $5 range.
SCRAP ALUMINUM AND ALUMINUM SHEETS: Excellent selection of scrap aluminum. Most sizes and thicknesses are available and the price is much less than other sources, especially if you would mail order it and pay for shipping. Large full sheets are available in a variety of thicknesses.
TITANIUM and other exotic metals: I am not sure why you would need it on an RV. Maybe it would make a good bullet shield for those who don't "check six" often. In any case, it and other exotic metals are available in the outside yard for exorbitant prices. As I recall, titanium was selling for more than $80 a pound.....makes you wonder what the hull of a nuclear sub costs.
DRILL BITS: This is one area that is never hit or miss. The tool crib has a huge selection of drills from "I can't see through the hole" to "I can walk through the hole". Six to twelve lengths are usually available. I am not sure why, but these bits seem to drill better than even our cobalt bits.
PNEUMATIC TOOLS: Fairly disappointing selection on air tools. While they have several hundred to choose from, most are not applicable to RV building (ed: need a 27X rivet gun?) Occasionally they do have a useful bargain show up and have an air hose handy to try it out. (ed: most of the good tools go to "regular buyers" before they hit the shelves.)
WIRE TIE TOOLS: This is a special tool (ed: known at Boeing as a Panduit gun) which Kathy says epitomizes how spoiled I am, but for $5, how could I resist?? It is actually a neat tool that sells now for $100. After wrapping the tie-wrap around the objects to be tied (e.g. a bundle of wires), the tool, which looks a bit like a pistol, is fitted onto the loose end of the tie wrap. A quick squeeze of the handle and the tie wrap is snugged up to the bundle at exactly the proper tension and trimmed off. (ed: this does not leave the sharp end that diagonal cutters leave.) Ok, ok, maybe I am spoiled...
HEAT SHRINK TUBING: Price is great but we found only a few sizes to choose from. The last time we were there the sizes consisted of mainly 1/2 inch and larger tubing.
OFFICE FURNITURE: Good prices on used office furniture. We bought an industrial strength lab bench (5ftX30") for $125. This is the heavy duty stuff with inch thick table top and no-mar surface.
UPHOLSTERY FABRIC: We keep hoping we will find a decent pattern. The fabric is surplus from aircraft interiors, so it is light weight and tough, but so far the only thing we have found is REALLY ugly.
MICRO STOP COUNTERSINKS: Industrial quality micro-stops in good condition. These are generally available for less than you will pay new for lesser quality units. Check them first as some are work and have a wobble.
OTHER STUFF: Pliers, no-mar pliers, used computer equipment, used office equipment, milling bits, etc.
FOAM: Bill Stapelton says that an economical (cheap) source for aircraft seats is Family Foam. They are located at 5311 Roosvelt Way NE, in Seattle. They will cut the cushions to your measurements and they produce lumbar supports that can be spray glued to your seat backs. For covering the above cushion, a 100% polyester material, sewn into pillow case style, will give an acceptable appearance. A year ago, the cost of both seats and fabric was approximately forty dollars. Hint: when determining the thickness of your seat cushion, remember to have your headset on.
Cowl Hinge: After engine cowling has been fitted and one half of the side hinge has been installed, reinstall the cowling but leave your trouble light on and inside the cowling. Now, when you darken your workshop, you can see the hinge shadow through the fiberglass. One precaution as you begin to drill the hinge rivets, there is a slight parallax error. Remember to check your edge margin after every few holes.
Exhaust Leaks: Don Wentz says that during his last annual he suspected a leak around his exhaust gaskets, at the head. "Not knowing any better, I assumed I would need to replace the gaskets. When shopping for one, a mechanic told me that the type I was using should last 10 years or more, especially if the plane is flown often."
"I told him I thought it was leaking and he told me how to check it. Stick a vacuum cleaner hose in the pipe, with the other end hooked up to the exhaust port of the vacuum, to blow air into the pipe. Use soapy water or 409 to look for bubbles. I didn't have a suitable vacuum, but my monokote modelers heatgun worked great. I stuffed it into the pipe, turned it on, and squirted 409 on the pipe to head joint. No bubbles at all. Concerned that there was not enough pressure, I loosened the nuts slowly. Eventually I had bubbles all over the place, but they disappeared when I re- tightened the nuts. The only leaks I found were very small ones at the slip joints, even the ball joints in the Vetterman exhausts were airtight."
"So there you have a simple method to check your exhausts for leaks. Frankly, I was very surprised that they would seal that well, but they do!"
Disclaimer: The Puget Sound RVator newsletter is not an official or unofficial publication of Vans Aircraft or any other corporation. All products reviewed or mentioned are not necessarily recommended for use by RV builders, but are included for information purposes only. All tips and bright ideas are representative only of the means by which the builder whose name is associated with the tip chose to build his/her aircraft. They are not meant to replace the plans or instructions from Vans Aircraft. No responsibility for liability is assumed, express or implied as to the suitability, accuracy, safety or approval thereof. Any party using the suggestions, ideas or examples does so at their own risk and discretion and without recourse against anyone. The editor of the Puget Sound RVator and the submitter of the tip or the bright idea are not responsible for any tip or bright idea misuse, incorrect construction or design failure, nor any other peril. Any material printed within may be reprinted without permission, but please give credit to the original source.