Dave Darling
Mar 23, 2004, 01:00 AM
!Introduction
| spec2
| @906111
|> <b>Wingspan:</b> |< 127"
|> <b>Wing Area:</b> |< 1100 sq in
|> <b>Weight:</b> |< 44 oz (with repairs, RTF)
|> <b>Radio:</b> |< Multiplex cockpit CC
|> <b>Manuf::</b> |< Vladimir Models
|> <b>Available From:</b> |< <a href="http://www.kennedycomposites.com/">Kennedy Composites</a>
|> <b>**</b> |< May be on back order.
<div class="dashed"><b>Editor’s Note:</b><br> This is not a traditional “review” of a plane. It is more a tale of one man’s odyssey with his plane. We hope you enjoy Dave’s early odyssey with his Ava.
</div>
@906112:Aluminum guide tubes taped and glued to the boom to support the carbon fiber control rod linkages.
@906113:Author Dave Darling shown with Ava (1) on a beautiful March morning.
!Introduction
I saw a write-up on the Ava: a composite Rudder/Elevator/Spoiler (RES) sailplane manufactured in the Ukraine and sold in the USA by Barry Kennedy of Kennedy Composites in Texas. Well, the photos weren't that exciting, and the price, $710 including shipping, was a real turn-off. Still, I began to hear more about the plane, and the fact that one won a large F3J contest in Europe piqued my interest a little more. My good friend, Byron Blakeslee, featured photos and a write-up on the plane in his report on the Southwest Classic event in the May 2003 issue of Quiet Flyer magazine. Then, I started to hear bad things, like Ava tip panels blowing off on launch in contests, and that cooled me a lot! Still, when Barry announced on the R/C Soaring Exchange that Vladimir Gavrilko, the creator of the Ava, would be at the Fall Soaring Festival in Visalia, I decided to look it over when I got down there.
Barry wasn't there when I arrived on the Thursday before the contest. He had driven to Los Angeles to pick up Vladimir. On Thursday I saw several Avas flying in practice. I was greatly impressed by the Ava's ability to fly in gusty conditions and to do very well in spot landings. Many of those flying their Avas appeared to have little stick time on them, but still, they were flying pretty well! On Friday I decided to mosey over to Barry's booth and do a little wheeling and dealing to see if a good deal could be struck. The price of $660 (less the shipping charges) was firm. After some reflection, I bit the bullet and bought an Ava! I also bought a custom Ukrainian-made carrying bag for another $95. Barry did come down $5 on that!
As I carried my goodies back to my motor home, my dear daddy's words rang in my ears, "A fool and his money are ... welcome EVERYWHERE!" But, so what! While at Visalia, I took a number of photos of Barry Kennedy's Ava, and also of Mike Reagan's. Mike had been flying his quite a while and while his was a little war weary, it still flew great! Mike used an entirely different system to run the carbon pushrods to the rudder and elevator. Instead of running them down the inside of the pod and boom, he drilled straight out through the back of the pod, and ran the pushrods down the outside of the boom, using aluminum tubing sections as guides. I thought that was a pretty good idea, and considered using it myself.
!Assembly
Once home, I started thinking about the Ava, and its assembly. Photos of another Ava published in Model Aviation magazine showed the servos mounted diagonally and well forward. Also, those servos shown were small with relatively low torque. I decided to use large, ball bearing servos for the rudder and elevator. The trick would to be to find a small servo to mount in the wing for the spoiler. The Ava uses only one spoiler in the wing center panel but it is 36 inches long and nearly 2 inches wide! I selected two Hitec HS-425 ball bearing servos for rudder and elevator, and an Expert SL-661 low-profile servo, sold by Horizon Hobby, for the spoiler. Barry Kennedy gave me several carbon pushrods, but they were of different diameters, so I opted to visit Aerospace Composites in Livermore. There I purchased a 96" long length of .080 carbon for the pushrods.
@906114:The tail servos, battery and switch mount easily in the pod. (See text regarding servo positions.)
@906115:Another view of the pod with the cover off.
I began the assembly of the Ava. First, I installed the servos, the on-off switch, and cut a hole for the receiver battery. I staggered the servo placement, placing one in the rearmost possible part of the pod, and the other just forward of that, on the opposite side. Here, I ran into my first problems. The deck that the servos were to mount into is very thin, perhaps only 1/20th inch thick. The servo mounting screws stripped out. So, I removed them and cut some small plywood rectangles and cyanoed them under the mounting areas, predrilled them and reinstalled the servos. Installing the switch and cutting a hole for the square 1100 mAh Nicad battery pack were uneventful.
My next problem came when I tried to trial fit the nose cone. My placement of the servos caused the servo arms to interfere with the cone. My only recourse was to shorten and trim the servo arms to allow clearance. If I were to do this again, I would place the servos more nearly in-line with each other. Finally, I obtained sufficient clearance for the servo arms to operate.
@906116:The rudder linkage.
Next I glued on the boom. This was a no-brainer, just use a little cyano and do it! However, on the back of the pod are three graphite mounts, two for the rudder and one for the stabilizer. To align these properly, I attached the center panel of the wing and placed the rudder and stab on their mounts. I moved them around until the stab and wing were parallel, and the rudder was vertical, then I cyanoed them in place. Next, I plotted the location of the holes to be drilled on the front and back of the pod, since I had decided to use Mike Reagan's method. The front holes were easy, the back ones very difficult, as I only had a 1/8" standard length drill to use. The holes didn't come out as nice on the back of the pod as I had hoped for, but they work! I cut twelve or fourteen 1/2-inch long sections of 1/8-inch diameter K&S aluminum tubing, and used them as guides down the fuselage. They can be Cyanoed in place, or tape can be used. I used cyano to hold the metric threaded couplers in place.
Barry and Vladimir didn't furnish clevises, but I had several Multiplex metal clevises that worked perfectly. I had to drill out the servo arms and the elevator control horn to accommodate these larger clevis pins, but that wasn't a problem. I used an adjustable control horn, Dubro #893, for the rudder. It was good that it was adjustable as it took some fiddling with it to get enough throw and to clear the rear of the pod on the right side.
@906115:Another view of the pod with the cover off.
@906117:This picture shows the nose cone covering the front of the pod. Note the homemade landing “skag” on the bottom of the nose cone.
!The First Flight
@906118:The author getting ready for the first hand launch of the day.
@906119:Another great shot of an Ava launch!
The plane was essentially done. The spoiler servo hadn't arrived yet, but I figured that was not necessary for a test flight. I mounted an old Hi Johnson tow hook in the bottom of the plane, through a piece of ply strip that I had epoxied in earlier. I checked the balance on the plane, it was right at 4 inches behind the leading edge of the wing. I took the Ava to Beyer High School flying field, and assembled it. Bob Hoffman was there, and he witnessed two beautiful, perfect hand glides! I had considered using a highstart, but we reasoned that in case of a problem, it was easier to get off a winch. After a little build-up of courage, I put the line on the Ava, and pressed on the winch pedal. The tow hook was way too far forward. Because I was uncertain of the launch, I dialed in a couple of clicks of "down" trim. The Ava popped off at about 45 feet, and with the down in the elevator, took off in a northwestern direction toward some trees. As it sped toward the approaching tree line, I momentarily took my eyes off the plane, and lost visual on it in the row of trees. I gave it right rudder and it spun into the ground. Its total time in the air off winch was perhaps fifteen seconds.
!!Disaster!
Pieces of the Ava bounced into the air. As I approached, I saw the fuselage was broken in half at the pod/boom joint. Both wings had shed their wingtips. One of these tip panels was damaged, with the tip broken off. The other appeared unscathed. The left outer panel was intact, except for a hole in the covering. The right outer panel had three breaks in the trailing edge, and the rear tip was broken in three pieces. The outer panel tip was broken off from the rest of the wing, and the balsa fillet in that corner was shattered. With a sick feeling, I gathered up the pieces and walked to the car. I couldn't believe it! Here I was with the most expensive plane I'd ever bought and flown, and it was reduced to scrap in a few seconds. What was I to do? When I got home, I unloaded the carnage and put it away. It seemed reasonable to wait a few days to calm down and analyze the cause of the crash before even considering repairs.
@906120:See how the plane blended into the trees on the doomed flight? <i>And this picture was taken with a zoom lens!</i>
!!What went wrong?
As I determined in the evaluation, I had placed the tow hook almost an inch forward of a suitable starting location. Even though I had hand glided the Ava with 3 or 4 clicks of "up" elevator to optimize the float, I had put down in the trim to compensate for any error on the tow hook location, meaning I thought it might have been too far back. This caused the Ava to out fly the winch, and pop off the line. Plus, with the added down in the elevator, the plane was covering a lot of ground, and flying out of close visual range. The transparent blue color blended into the trees in my color-defective eyes, and I was in a situation where there was little I could do but try to turn the plane around. By then, it was behind a baseball backstop and near a fence, so I probably fed down into it to avoid those two barriers.
!!Postmortem
I thought about these circumstances for several days, and then concluded that perhaps it was time to examine the wreckage. I had no idea how to repair the breaks in the wing trailing edge, so I looked at the fuselage. The nose cone was intact, as was the forward part of the pod. The rudder and stab, and their mounts, were undamaged.
However, the pod and boom had separated where the boom connects with the pod. The extrusion of the pod that enters the boom had been neatly severed by the front of the boom, and remained inside of the boom. This seemed to be a serious design defect, as the shear forces on the pod would always try to sever the pod from the boom. Since there was access to the inside of the pod from the opening under the wing, I reasoned that if I could find a properly tapered mandrel, I could make a sleeve to go inside the pod and the boom, and securely join them back together. That was easier said than done. I thought that perhaps a deep-sea fishing rod blank would do the trick, and drove to the large fishing supplies store in Manteca to see what they had. That journey was for nothing, as the nearest they had was what they called an inexpensive fishing rod for $40. I still might have bought it, except that I wasn't certain the taper was correct.
!Rebuilding
After another day of thinking about it, I remembered reading that one could make a plug by soaking 1/32 balsa and wrapping it around a curved surface to dry. I tried that four times, and all I got was split balsa. I looked through hardware and crafts stores for something with a similar taper. I was driving toward the local hobby shop, when I had a brainstorm. How about a pool cue? It is tapered, and somewhere on it, it might have the right taper. I asked the saleslady at the hobby shop if there were any pool halls in Modesto. She replied that there were at least two she knew of, and the closest one was just down McHenry Avenue, at Boulevard Billiards. I drove there, hoping to find something useful. I explained my dilemma to the proprietor, and asked him if he had any old or damaged cues. He opened a door where custodial supplies were held, and, behold, there were five or six cues! He picked up one with a tip broken off, and asked me if that would do. I looked at and felt that was the right shape to act as a mandrel. I asked him what the price was, and he replied, "How fast can you run?" I determined that he meant that I could have the cue for nothing! I thanked him profusely, and drove home to compare the taper to the boom. It was a good fit! Not being adept at fiberglassing, I called Jeff Hunter, who knows more about composite materials and their use than anyone else in my club. He invited me to come over and talk. I brought my old supply of fiberglass cloth and carbon fiber, along with the cue and broken fuselage parts. We reexamined the fit and marked the cue as to where the splicing plug should be made. Jeff rubbed on some mold release onto the cue, and laid up some of my light glass cloth around it. Then, he cut strands of carbon fiber and laid them on the fiberglass, first running lengthwise, then around the cue. He used a very strong, but long-curing epoxy for the work. He put the cue with the plug on it away and said to let it cure for at least a week.
The next week, I returned to Jeff's, and he felt that the plug was still not adequately dry. I took it home and let it cure for several more days, going over it with a hair dryer, and letting it set on the top of a bookcase, where the warmth would be greatest. After all this, I reasoned that it was cured, and tried to get the plug off the cue. No luck! I was starting to think ahead about repairing the wings, and there were no places in Modesto where carbon and composite materials were sold, so I drove to Livermore, where Aerospace Composites is now located. There a very pleasant lady let me browse around until George Sparr, owner of the company, arrived. I showed him the plug, and he said that it would never slide off the cue. He advised me to split the plug, and remove it. He then told me a better way to make a plug. He suggested wrapping the cue with waxed paper, then using some of his uni-web graphite, UP-06, 3.5 oz. material to wrap it around the plug when soaked in epoxy, then cover tightly with a plastic wrap like saran wrap. He looked at the craftsmanship of the damaged Ava parts, and said that a plane like that could never be made in the USA, because the labor was too expensive, and the material and mold cost would be prohibitive. He suggested that to repair the trailing edge of the wings, that I use some of his CL1-41, .007" x 48" carbon laminate strips. He said to glue it to the broken sections, rough up the broken sections with #400 sandpaper, clean with alcohol, and glue with cyano. He said that one side of his carbon lam was purposely left rough, and it could be applied as is. I purchased the laminate strips and the graphite and left. After a speedy trip to Sheldon’s Hobby Shop in San Jose to purchase some transparent blue Ultracote, I headed home and started the repairs.
I did split the existing sleeve on the pool cue, and it did slide off, finally. I decided to use it as a basis for a thicker sleeve, and, after trial fitting in the boom, realized that the smallest end could be built up with the uni-web graphite and still fit in the pod and boom. I wrapped some waxed paper around the cue and slid the split sleeve over it. Then I mixed up some standard hobby shop-type 30-minute epoxy and spread it over the sleeve, after cutting the graphite to fit. After two layers were soaked in epoxy and laid on, I wrapped the finished product in plastic wrap and squeezed it out. I let it dry for 24 hours and removed the newly completed plug. I removed the plastic wrap and trial fit it to the boom. It fit well into the boom, and entered the pod, too, but there seemed to be too much slack beyond the neck of the pod. I reasoned that perhaps another build-up of graphite and epoxy could enlarge the plug and make it fit better. It worked! I trimmed the plug to a length of about four inches, and after some sanding to the plug and grinding the inside of the boom, it mated well. Some more trial fitting was done in the pod, and then the plug was inserted in the pod, and then in the boom. Before gluing it, I put strips of masking tape around the front of the boom and back of the pod. I reinstalled the rudder and elevator on the boom, and bolted the wing center section on the pod. I adjusted each until the elevator was parallel to the wing, and the rudder was vertical to it. I scribed a line on both pieces of tape as an alignment mark. I took the wing off the pod and the rudder and stab off the boom. Some 30-minute epoxy was used to hold the plug into the pod, and the boom was used to check alignment. After the 30-minute epoxy was dry, I mixed up some 5-minute epoxy and glued the boom on. When it was dry, I checked the alignment, and it was perfect!
@906121:This picture shows the boom meeting the pod as well as the trailing edge of carbon fiber on the wings center section. You can post that picture and add this paragraph: The above picture shows the repaired tail boom reconnected to the back of the pod. The break was exactly on the line where the boom enters the pod. The repairs were all done internally as discussed elsewhere in this article and thus nothing shows externally about that repair. This picture also shows the thin trailing edge of carbon fiber on the center section of the wing. The same size carbon fiber was used in the wing tips where the breaks and repairs to the wing occured. The wing repairs are not visible and no pictures were taken while the plane was damaged and in need of repair.
One wing tip was damaged, so I used cyano to repair the balsa tip, and two pieces of the .007 carbon laminate to repair the trailing edge, one cyanoed on the top of the break and one on the bottom, to repair it. A little sanding and the repair was almost invisible! The other damaged wing panel was more difficult to repair but using the new materials and patience I finished the repairs. I checked the pushrods and made sure the fit was smooth and free of resistance. I reinstalled the clevises, mounted the tail and wings and examined the repairs. It looked great! Finally, I added the "AVA" and AMA number graphics I purchased from Mike Lee at the Fall Soaring Festival, and the plane was ready to test fly again!
!Back to the Flight Line!
@906122:A side view of the second high start launch of the day.
@906123:The loop of the high start has dropped off of the launch hook on the bottom of the Ava. The parachute on the high start is starting to open as the Ava flies forward.
On a nice Sunday morning, I took the Ava back to the Beyer High School athletic field, and gave it a couple of hand launches. The plane again required a lot of down trim, but did glide well. So, I put it up on the high start, and it was quite squirrelly! Feeling less than confident, I put her away for the rest of the morning, and flew something else. The next attempt at trimming the Ava was at our Modesto Reservoir flying field. After several hand glides, I put it up on the winch and it popped off. Several more tries had the same result for me. When I did finally get a decent launch, the plane would not stabilize! Trim was either too much down, or too much up, no middle ground! I put it away for the day and went home.
@906124:A close-up of the Ava after coming off of the high start.
@906125:A view of the Ava hunting for a thermal.
The next day, I examined the plane for potential problems. Since the problem was in vertical control, I looked at the full-flying stabilizer first. Lo and behold, the stab was very wobbly! A closer exam showed that one of the two steel pins holding the elevator pivot had worked completely out of the hole on the elevator. The second pin was also loose. To correct these problems, I put a drop of cyanoacrylic glue on a toothpick, and put those drops on the pins. Voila, no more loose pins! The following Sunday, I took the Ava back to Beyer and did some more hand launches, and a launch on the high start. The three flights I attempted were successful, but the plane still didn’t handle well. I tried various adjustments on the flying stabilizer, but it just didn’t fly as I wanted it to. I couldn’t figure out what was wrong.
@906126:The Ava banking in a turn.
@906127:The Ava just before touch down with the spoiler deployed.
That same week, a few of my fellow club members and I decided to go out to Modesto Reservoir, where our large flying field is. The field is huge, but the ground is quite rough with many small rocks and clods of dirt on the surface. There was no grass to speak of there, as it is a flying site in process. We were using a small Graupner winch to launch. I gave my Ava a couple of test glides after assembly, and waited my turn to launch on the winch. When I did, the Ava popped off, and I looped it to get back down. The Ava seemed to “hunt,” that is it did not glide in a smooth and predictable manner. My club mates took a look at it and the majority opinion was that it was tail heavy. I had the balance point marked on the fuselage with tape, under the wing, at the suggested 100 mm. from the leading edge. The guys were right! It was tail heavy, perhaps 10 mm. behind the recommended CG. So, I added some lead under the canopy, and held it in place with plastic tape. The next launch was much better! The plane tracked and “grooved” much better than before. The next flight was good for about 37 minutes! The lift was spotty, but generally good all over. Several of my club mates had flights of over 15 minutes, with one getting a 47-minute flight! My transmitter meter indicated that I was below 50% capacity, so I put it away for the day. What a great day for flying it was!
@906128:Beautiful, successful flying at last!
@906129:Dave let Jeff and Lisa Hunter fly his Ava.
As I examined the Ava when I put it away, I discovered a small separation on the graphite section of a wing panel. I also noticed that the sub-rudder was getting dented from the rough landings at this field. I made a mental note to fix these. The next day, at home, I replaced the temporary lead weight I had added at the field with lead shot and epoxy. This increased the Ava’s overall weight to 40.9 oz. I next took several drops of instant C.A. glue and applied it to the delaminated area on the wing, holding it in place with wax paper until it dried. I added several pieces of 2-inch wide transparent packing tape to the outer panel dihedral breaks, to protect the covering from field dings. And finally, I bent a small curved piece of music wire and, after drilling two small holes in the forward portion of the rudder, I glued it in place with C.A. It was set for its next flight!
To be able to set the elevator with any consistency, I devised a tool made of wood and picture matting to mark the center of the leading edge of the stab, but in a phone conversation with Barry Kennedy, he suggested using the leading edge of the rudder to set the angle on the trailing edge of the elevator. I adopted this simple and accurate idea.
+906130:A brief introduction of Ava and her equipment, followed by a nice high start launch and flight.
The plane is now sorted out and flying well. Every time I fly it, it just gets better and better. I have switched from my simple multiplex Pico transmitter to the more advanced Multiplex Cockpit MM transmitter. I have programmed in elevator compensation mix for when I deploy the spoiler. It works wonderfully but I need to practice with it more. At a recent club thermal duration contest I finished fourth! My flight times were good but my landing scores were not. Fortunately, I have a few more weeks to practice my landings before my first large contest of the season.
+906131:Ava goes thermal hunting.
!Conclusion
I am so happy with how my Ava is flying now that, despite the cost, I have ordered and received a second Ava to serve as a back-up plane for competitions. I love how my first one now handles and responds to lift. I have had several additional long flights with my first Ava in practice sessions. I just need to spend some time shooting my landings to get in the proper pattern to land on time and on target. I hope you enjoy the video of my Ava in flight and get a little bit of a feel for how well she flies. On Ava number two I have beefed up the pod/tail boom connection and I am otherwise setting it up pretty much like the first one. When I last checked I learned that there is a waiting list to get one of these planes…it is worth the wait.
| spec2
| @906111
|> <b>Wingspan:</b> |< 127"
|> <b>Wing Area:</b> |< 1100 sq in
|> <b>Weight:</b> |< 44 oz (with repairs, RTF)
|> <b>Radio:</b> |< Multiplex cockpit CC
|> <b>Manuf::</b> |< Vladimir Models
|> <b>Available From:</b> |< <a href="http://www.kennedycomposites.com/">Kennedy Composites</a>
|> <b>**</b> |< May be on back order.
<div class="dashed"><b>Editor’s Note:</b><br> This is not a traditional “review” of a plane. It is more a tale of one man’s odyssey with his plane. We hope you enjoy Dave’s early odyssey with his Ava.
</div>
@906112:Aluminum guide tubes taped and glued to the boom to support the carbon fiber control rod linkages.
@906113:Author Dave Darling shown with Ava (1) on a beautiful March morning.
!Introduction
I saw a write-up on the Ava: a composite Rudder/Elevator/Spoiler (RES) sailplane manufactured in the Ukraine and sold in the USA by Barry Kennedy of Kennedy Composites in Texas. Well, the photos weren't that exciting, and the price, $710 including shipping, was a real turn-off. Still, I began to hear more about the plane, and the fact that one won a large F3J contest in Europe piqued my interest a little more. My good friend, Byron Blakeslee, featured photos and a write-up on the plane in his report on the Southwest Classic event in the May 2003 issue of Quiet Flyer magazine. Then, I started to hear bad things, like Ava tip panels blowing off on launch in contests, and that cooled me a lot! Still, when Barry announced on the R/C Soaring Exchange that Vladimir Gavrilko, the creator of the Ava, would be at the Fall Soaring Festival in Visalia, I decided to look it over when I got down there.
Barry wasn't there when I arrived on the Thursday before the contest. He had driven to Los Angeles to pick up Vladimir. On Thursday I saw several Avas flying in practice. I was greatly impressed by the Ava's ability to fly in gusty conditions and to do very well in spot landings. Many of those flying their Avas appeared to have little stick time on them, but still, they were flying pretty well! On Friday I decided to mosey over to Barry's booth and do a little wheeling and dealing to see if a good deal could be struck. The price of $660 (less the shipping charges) was firm. After some reflection, I bit the bullet and bought an Ava! I also bought a custom Ukrainian-made carrying bag for another $95. Barry did come down $5 on that!
As I carried my goodies back to my motor home, my dear daddy's words rang in my ears, "A fool and his money are ... welcome EVERYWHERE!" But, so what! While at Visalia, I took a number of photos of Barry Kennedy's Ava, and also of Mike Reagan's. Mike had been flying his quite a while and while his was a little war weary, it still flew great! Mike used an entirely different system to run the carbon pushrods to the rudder and elevator. Instead of running them down the inside of the pod and boom, he drilled straight out through the back of the pod, and ran the pushrods down the outside of the boom, using aluminum tubing sections as guides. I thought that was a pretty good idea, and considered using it myself.
!Assembly
Once home, I started thinking about the Ava, and its assembly. Photos of another Ava published in Model Aviation magazine showed the servos mounted diagonally and well forward. Also, those servos shown were small with relatively low torque. I decided to use large, ball bearing servos for the rudder and elevator. The trick would to be to find a small servo to mount in the wing for the spoiler. The Ava uses only one spoiler in the wing center panel but it is 36 inches long and nearly 2 inches wide! I selected two Hitec HS-425 ball bearing servos for rudder and elevator, and an Expert SL-661 low-profile servo, sold by Horizon Hobby, for the spoiler. Barry Kennedy gave me several carbon pushrods, but they were of different diameters, so I opted to visit Aerospace Composites in Livermore. There I purchased a 96" long length of .080 carbon for the pushrods.
@906114:The tail servos, battery and switch mount easily in the pod. (See text regarding servo positions.)
@906115:Another view of the pod with the cover off.
I began the assembly of the Ava. First, I installed the servos, the on-off switch, and cut a hole for the receiver battery. I staggered the servo placement, placing one in the rearmost possible part of the pod, and the other just forward of that, on the opposite side. Here, I ran into my first problems. The deck that the servos were to mount into is very thin, perhaps only 1/20th inch thick. The servo mounting screws stripped out. So, I removed them and cut some small plywood rectangles and cyanoed them under the mounting areas, predrilled them and reinstalled the servos. Installing the switch and cutting a hole for the square 1100 mAh Nicad battery pack were uneventful.
My next problem came when I tried to trial fit the nose cone. My placement of the servos caused the servo arms to interfere with the cone. My only recourse was to shorten and trim the servo arms to allow clearance. If I were to do this again, I would place the servos more nearly in-line with each other. Finally, I obtained sufficient clearance for the servo arms to operate.
@906116:The rudder linkage.
Next I glued on the boom. This was a no-brainer, just use a little cyano and do it! However, on the back of the pod are three graphite mounts, two for the rudder and one for the stabilizer. To align these properly, I attached the center panel of the wing and placed the rudder and stab on their mounts. I moved them around until the stab and wing were parallel, and the rudder was vertical, then I cyanoed them in place. Next, I plotted the location of the holes to be drilled on the front and back of the pod, since I had decided to use Mike Reagan's method. The front holes were easy, the back ones very difficult, as I only had a 1/8" standard length drill to use. The holes didn't come out as nice on the back of the pod as I had hoped for, but they work! I cut twelve or fourteen 1/2-inch long sections of 1/8-inch diameter K&S aluminum tubing, and used them as guides down the fuselage. They can be Cyanoed in place, or tape can be used. I used cyano to hold the metric threaded couplers in place.
Barry and Vladimir didn't furnish clevises, but I had several Multiplex metal clevises that worked perfectly. I had to drill out the servo arms and the elevator control horn to accommodate these larger clevis pins, but that wasn't a problem. I used an adjustable control horn, Dubro #893, for the rudder. It was good that it was adjustable as it took some fiddling with it to get enough throw and to clear the rear of the pod on the right side.
@906115:Another view of the pod with the cover off.
@906117:This picture shows the nose cone covering the front of the pod. Note the homemade landing “skag” on the bottom of the nose cone.
!The First Flight
@906118:The author getting ready for the first hand launch of the day.
@906119:Another great shot of an Ava launch!
The plane was essentially done. The spoiler servo hadn't arrived yet, but I figured that was not necessary for a test flight. I mounted an old Hi Johnson tow hook in the bottom of the plane, through a piece of ply strip that I had epoxied in earlier. I checked the balance on the plane, it was right at 4 inches behind the leading edge of the wing. I took the Ava to Beyer High School flying field, and assembled it. Bob Hoffman was there, and he witnessed two beautiful, perfect hand glides! I had considered using a highstart, but we reasoned that in case of a problem, it was easier to get off a winch. After a little build-up of courage, I put the line on the Ava, and pressed on the winch pedal. The tow hook was way too far forward. Because I was uncertain of the launch, I dialed in a couple of clicks of "down" trim. The Ava popped off at about 45 feet, and with the down in the elevator, took off in a northwestern direction toward some trees. As it sped toward the approaching tree line, I momentarily took my eyes off the plane, and lost visual on it in the row of trees. I gave it right rudder and it spun into the ground. Its total time in the air off winch was perhaps fifteen seconds.
!!Disaster!
Pieces of the Ava bounced into the air. As I approached, I saw the fuselage was broken in half at the pod/boom joint. Both wings had shed their wingtips. One of these tip panels was damaged, with the tip broken off. The other appeared unscathed. The left outer panel was intact, except for a hole in the covering. The right outer panel had three breaks in the trailing edge, and the rear tip was broken in three pieces. The outer panel tip was broken off from the rest of the wing, and the balsa fillet in that corner was shattered. With a sick feeling, I gathered up the pieces and walked to the car. I couldn't believe it! Here I was with the most expensive plane I'd ever bought and flown, and it was reduced to scrap in a few seconds. What was I to do? When I got home, I unloaded the carnage and put it away. It seemed reasonable to wait a few days to calm down and analyze the cause of the crash before even considering repairs.
@906120:See how the plane blended into the trees on the doomed flight? <i>And this picture was taken with a zoom lens!</i>
!!What went wrong?
As I determined in the evaluation, I had placed the tow hook almost an inch forward of a suitable starting location. Even though I had hand glided the Ava with 3 or 4 clicks of "up" elevator to optimize the float, I had put down in the trim to compensate for any error on the tow hook location, meaning I thought it might have been too far back. This caused the Ava to out fly the winch, and pop off the line. Plus, with the added down in the elevator, the plane was covering a lot of ground, and flying out of close visual range. The transparent blue color blended into the trees in my color-defective eyes, and I was in a situation where there was little I could do but try to turn the plane around. By then, it was behind a baseball backstop and near a fence, so I probably fed down into it to avoid those two barriers.
!!Postmortem
I thought about these circumstances for several days, and then concluded that perhaps it was time to examine the wreckage. I had no idea how to repair the breaks in the wing trailing edge, so I looked at the fuselage. The nose cone was intact, as was the forward part of the pod. The rudder and stab, and their mounts, were undamaged.
However, the pod and boom had separated where the boom connects with the pod. The extrusion of the pod that enters the boom had been neatly severed by the front of the boom, and remained inside of the boom. This seemed to be a serious design defect, as the shear forces on the pod would always try to sever the pod from the boom. Since there was access to the inside of the pod from the opening under the wing, I reasoned that if I could find a properly tapered mandrel, I could make a sleeve to go inside the pod and the boom, and securely join them back together. That was easier said than done. I thought that perhaps a deep-sea fishing rod blank would do the trick, and drove to the large fishing supplies store in Manteca to see what they had. That journey was for nothing, as the nearest they had was what they called an inexpensive fishing rod for $40. I still might have bought it, except that I wasn't certain the taper was correct.
!Rebuilding
After another day of thinking about it, I remembered reading that one could make a plug by soaking 1/32 balsa and wrapping it around a curved surface to dry. I tried that four times, and all I got was split balsa. I looked through hardware and crafts stores for something with a similar taper. I was driving toward the local hobby shop, when I had a brainstorm. How about a pool cue? It is tapered, and somewhere on it, it might have the right taper. I asked the saleslady at the hobby shop if there were any pool halls in Modesto. She replied that there were at least two she knew of, and the closest one was just down McHenry Avenue, at Boulevard Billiards. I drove there, hoping to find something useful. I explained my dilemma to the proprietor, and asked him if he had any old or damaged cues. He opened a door where custodial supplies were held, and, behold, there were five or six cues! He picked up one with a tip broken off, and asked me if that would do. I looked at and felt that was the right shape to act as a mandrel. I asked him what the price was, and he replied, "How fast can you run?" I determined that he meant that I could have the cue for nothing! I thanked him profusely, and drove home to compare the taper to the boom. It was a good fit! Not being adept at fiberglassing, I called Jeff Hunter, who knows more about composite materials and their use than anyone else in my club. He invited me to come over and talk. I brought my old supply of fiberglass cloth and carbon fiber, along with the cue and broken fuselage parts. We reexamined the fit and marked the cue as to where the splicing plug should be made. Jeff rubbed on some mold release onto the cue, and laid up some of my light glass cloth around it. Then, he cut strands of carbon fiber and laid them on the fiberglass, first running lengthwise, then around the cue. He used a very strong, but long-curing epoxy for the work. He put the cue with the plug on it away and said to let it cure for at least a week.
The next week, I returned to Jeff's, and he felt that the plug was still not adequately dry. I took it home and let it cure for several more days, going over it with a hair dryer, and letting it set on the top of a bookcase, where the warmth would be greatest. After all this, I reasoned that it was cured, and tried to get the plug off the cue. No luck! I was starting to think ahead about repairing the wings, and there were no places in Modesto where carbon and composite materials were sold, so I drove to Livermore, where Aerospace Composites is now located. There a very pleasant lady let me browse around until George Sparr, owner of the company, arrived. I showed him the plug, and he said that it would never slide off the cue. He advised me to split the plug, and remove it. He then told me a better way to make a plug. He suggested wrapping the cue with waxed paper, then using some of his uni-web graphite, UP-06, 3.5 oz. material to wrap it around the plug when soaked in epoxy, then cover tightly with a plastic wrap like saran wrap. He looked at the craftsmanship of the damaged Ava parts, and said that a plane like that could never be made in the USA, because the labor was too expensive, and the material and mold cost would be prohibitive. He suggested that to repair the trailing edge of the wings, that I use some of his CL1-41, .007" x 48" carbon laminate strips. He said to glue it to the broken sections, rough up the broken sections with #400 sandpaper, clean with alcohol, and glue with cyano. He said that one side of his carbon lam was purposely left rough, and it could be applied as is. I purchased the laminate strips and the graphite and left. After a speedy trip to Sheldon’s Hobby Shop in San Jose to purchase some transparent blue Ultracote, I headed home and started the repairs.
I did split the existing sleeve on the pool cue, and it did slide off, finally. I decided to use it as a basis for a thicker sleeve, and, after trial fitting in the boom, realized that the smallest end could be built up with the uni-web graphite and still fit in the pod and boom. I wrapped some waxed paper around the cue and slid the split sleeve over it. Then I mixed up some standard hobby shop-type 30-minute epoxy and spread it over the sleeve, after cutting the graphite to fit. After two layers were soaked in epoxy and laid on, I wrapped the finished product in plastic wrap and squeezed it out. I let it dry for 24 hours and removed the newly completed plug. I removed the plastic wrap and trial fit it to the boom. It fit well into the boom, and entered the pod, too, but there seemed to be too much slack beyond the neck of the pod. I reasoned that perhaps another build-up of graphite and epoxy could enlarge the plug and make it fit better. It worked! I trimmed the plug to a length of about four inches, and after some sanding to the plug and grinding the inside of the boom, it mated well. Some more trial fitting was done in the pod, and then the plug was inserted in the pod, and then in the boom. Before gluing it, I put strips of masking tape around the front of the boom and back of the pod. I reinstalled the rudder and elevator on the boom, and bolted the wing center section on the pod. I adjusted each until the elevator was parallel to the wing, and the rudder was vertical to it. I scribed a line on both pieces of tape as an alignment mark. I took the wing off the pod and the rudder and stab off the boom. Some 30-minute epoxy was used to hold the plug into the pod, and the boom was used to check alignment. After the 30-minute epoxy was dry, I mixed up some 5-minute epoxy and glued the boom on. When it was dry, I checked the alignment, and it was perfect!
@906121:This picture shows the boom meeting the pod as well as the trailing edge of carbon fiber on the wings center section. You can post that picture and add this paragraph: The above picture shows the repaired tail boom reconnected to the back of the pod. The break was exactly on the line where the boom enters the pod. The repairs were all done internally as discussed elsewhere in this article and thus nothing shows externally about that repair. This picture also shows the thin trailing edge of carbon fiber on the center section of the wing. The same size carbon fiber was used in the wing tips where the breaks and repairs to the wing occured. The wing repairs are not visible and no pictures were taken while the plane was damaged and in need of repair.
One wing tip was damaged, so I used cyano to repair the balsa tip, and two pieces of the .007 carbon laminate to repair the trailing edge, one cyanoed on the top of the break and one on the bottom, to repair it. A little sanding and the repair was almost invisible! The other damaged wing panel was more difficult to repair but using the new materials and patience I finished the repairs. I checked the pushrods and made sure the fit was smooth and free of resistance. I reinstalled the clevises, mounted the tail and wings and examined the repairs. It looked great! Finally, I added the "AVA" and AMA number graphics I purchased from Mike Lee at the Fall Soaring Festival, and the plane was ready to test fly again!
!Back to the Flight Line!
@906122:A side view of the second high start launch of the day.
@906123:The loop of the high start has dropped off of the launch hook on the bottom of the Ava. The parachute on the high start is starting to open as the Ava flies forward.
On a nice Sunday morning, I took the Ava back to the Beyer High School athletic field, and gave it a couple of hand launches. The plane again required a lot of down trim, but did glide well. So, I put it up on the high start, and it was quite squirrelly! Feeling less than confident, I put her away for the rest of the morning, and flew something else. The next attempt at trimming the Ava was at our Modesto Reservoir flying field. After several hand glides, I put it up on the winch and it popped off. Several more tries had the same result for me. When I did finally get a decent launch, the plane would not stabilize! Trim was either too much down, or too much up, no middle ground! I put it away for the day and went home.
@906124:A close-up of the Ava after coming off of the high start.
@906125:A view of the Ava hunting for a thermal.
The next day, I examined the plane for potential problems. Since the problem was in vertical control, I looked at the full-flying stabilizer first. Lo and behold, the stab was very wobbly! A closer exam showed that one of the two steel pins holding the elevator pivot had worked completely out of the hole on the elevator. The second pin was also loose. To correct these problems, I put a drop of cyanoacrylic glue on a toothpick, and put those drops on the pins. Voila, no more loose pins! The following Sunday, I took the Ava back to Beyer and did some more hand launches, and a launch on the high start. The three flights I attempted were successful, but the plane still didn’t handle well. I tried various adjustments on the flying stabilizer, but it just didn’t fly as I wanted it to. I couldn’t figure out what was wrong.
@906126:The Ava banking in a turn.
@906127:The Ava just before touch down with the spoiler deployed.
That same week, a few of my fellow club members and I decided to go out to Modesto Reservoir, where our large flying field is. The field is huge, but the ground is quite rough with many small rocks and clods of dirt on the surface. There was no grass to speak of there, as it is a flying site in process. We were using a small Graupner winch to launch. I gave my Ava a couple of test glides after assembly, and waited my turn to launch on the winch. When I did, the Ava popped off, and I looped it to get back down. The Ava seemed to “hunt,” that is it did not glide in a smooth and predictable manner. My club mates took a look at it and the majority opinion was that it was tail heavy. I had the balance point marked on the fuselage with tape, under the wing, at the suggested 100 mm. from the leading edge. The guys were right! It was tail heavy, perhaps 10 mm. behind the recommended CG. So, I added some lead under the canopy, and held it in place with plastic tape. The next launch was much better! The plane tracked and “grooved” much better than before. The next flight was good for about 37 minutes! The lift was spotty, but generally good all over. Several of my club mates had flights of over 15 minutes, with one getting a 47-minute flight! My transmitter meter indicated that I was below 50% capacity, so I put it away for the day. What a great day for flying it was!
@906128:Beautiful, successful flying at last!
@906129:Dave let Jeff and Lisa Hunter fly his Ava.
As I examined the Ava when I put it away, I discovered a small separation on the graphite section of a wing panel. I also noticed that the sub-rudder was getting dented from the rough landings at this field. I made a mental note to fix these. The next day, at home, I replaced the temporary lead weight I had added at the field with lead shot and epoxy. This increased the Ava’s overall weight to 40.9 oz. I next took several drops of instant C.A. glue and applied it to the delaminated area on the wing, holding it in place with wax paper until it dried. I added several pieces of 2-inch wide transparent packing tape to the outer panel dihedral breaks, to protect the covering from field dings. And finally, I bent a small curved piece of music wire and, after drilling two small holes in the forward portion of the rudder, I glued it in place with C.A. It was set for its next flight!
To be able to set the elevator with any consistency, I devised a tool made of wood and picture matting to mark the center of the leading edge of the stab, but in a phone conversation with Barry Kennedy, he suggested using the leading edge of the rudder to set the angle on the trailing edge of the elevator. I adopted this simple and accurate idea.
+906130:A brief introduction of Ava and her equipment, followed by a nice high start launch and flight.
The plane is now sorted out and flying well. Every time I fly it, it just gets better and better. I have switched from my simple multiplex Pico transmitter to the more advanced Multiplex Cockpit MM transmitter. I have programmed in elevator compensation mix for when I deploy the spoiler. It works wonderfully but I need to practice with it more. At a recent club thermal duration contest I finished fourth! My flight times were good but my landing scores were not. Fortunately, I have a few more weeks to practice my landings before my first large contest of the season.
+906131:Ava goes thermal hunting.
!Conclusion
I am so happy with how my Ava is flying now that, despite the cost, I have ordered and received a second Ava to serve as a back-up plane for competitions. I love how my first one now handles and responds to lift. I have had several additional long flights with my first Ava in practice sessions. I just need to spend some time shooting my landings to get in the proper pattern to land on time and on target. I hope you enjoy the video of my Ava in flight and get a little bit of a feel for how well she flies. On Ava number two I have beefed up the pod/tail boom connection and I am otherwise setting it up pretty much like the first one. When I last checked I learned that there is a waiting list to get one of these planes…it is worth the wait.