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The .020 Rivets

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The .020 Rivets

Post  modelbuilder49 on Fri Oct 02, 2015 9:39 am

Greetings!  Well, it's been a long road but I can say I DID IT!!  A few months ago I read about the Cox Profile Scale Contest and decided I wanted to participate. So, here's my story and I'm sticking to it!! :

April 16, 2015
I came into the workshop and set to building a 1/2A plane called the RIVETS. I downloaded the plans from the OuterZone collection but they were for the 26" wingspan radio controlled model .02 Rivets designed by Owen Kampen back in 1967. However, the rules for the Cox Profile Scale Contest requires that the plane be control line with a profile fuselage and a minimum 12” fuselage and 15” wingspan. I opted to make the fuselage from ¼” sheet balsa, the wing was cut from a piece of Sig airfoil shaped balsa and the horizontal and vertical stabilizers were made from 3/32” balsa. The horizontal stab was outlined with four pieces of 3/32” x 1/8” balsa. It was at this point, where I remembered to begin the documentation, when it was ready for the mounting of the bellcrank and elevator controls. I tried to imagine what it would look like with a Tee Dee .051 and it really looked like it would be be too large for the plane not to mention it was so nose heavy it wouldn’t set up on the landing gear. So for the heck of it I used a dab of thick CA on one of the mounting ears of my Cox .020 and it looked just right. Oh well! As I mentioned, the plans for this plane are actually for a much larger full body R/C model.

April 17, 2015
I completed the mounting of the bellcrank, elevator and pushrod using a Brodak 1/2A bellcrank, p/n BB-390, I set up the controls. The lead outs were made of .0.015” solid wire and the pushrod was made from a piece of .054” music wire. Now, I had to order an assortment of small Dubro wheels to get some suitable wheels. From the looks of it, the Cox .020 seems to be the better match because of the ground clearance for the propeller. With either engine mounted, it was definitely tail heavy and will require some tail weight just to sit on the wheels. By 1745 the RIVETS was ready for finishing.

Sunday, April 19, 2015
I added some ¼” triangle stock to the underside of the horizontal stab of the RIVETS to provide a modicum of reinforcement. Once I was satisfied with the finished sanding and shaping, it was ready for the application of its finish.

April 22, 2015
I applied a coat of Coverite to both of the RIVETS it up to dry. Then I spent a couple of hours making up a set of 35 foot, .008” steel flying lines for my 1/2A’s and when I finished, I did a Google search for what I thought would be a kool finish and began covering the RIVETS using Monokote.

April 23, 2015
I resumed work covering the RIVETS. I could not complete the covering scheme as planned because I ran out of yellow Monokote for the bottom so I had to settle for covering the bottom of the wing and the horizontal stab in red. I think it looks all right! By 1540 I completed the covering process and was ready to apply the trim and mount the engine. Unfortunately, the wheels I ordered had not yet arrived. I worked until 1830 or so to complete the trim for the RIVETS. I hammered a 1/4 ounce fishing sinker flat to about 1/16" thick such that I was able to use the Dremel router bit to inset it flush into the outboard wing; then it was covered with with a piece of Monokote. Next, I mounted the Cox 020 engine to document the construction finish but now I have to wait for the wheels. I think it looks pretty good.

April 28, 2015
I received my order from Tower Hobby with the wheels I needed for the RIVETS and some APC 6” propellers. I chose to mount the Dubro MW100 foam wheels, since they weighed only 1.1 grams each, on the RIVETS and it really looks nice now. So my final numbers for the Rivets are: Cox 020 engine with a Thimble Drone 4.5 x 2P propeller, 15.75” wingspan, 13.25 fuselage length, 15.125” L.O.A. with a final ready to fly weight of 3.3 ounces. Now, to set a date for a documented flight!!

April 29, 2015
Just to be sure, I re-read the rules for the Cox Profile Reed Speed Contest and it was then that a lightbulb came on: the engine, thus the plane wasn't legal! The rules specified a .049 or.051 or combination equal to that displacement. Now I was feeling a bit depressed until a friend told me about the 6th Balsa Builders Conversion Contest Thread being hosted on RCGroups. After reading about it I decided to enter the Rivets. Now to get a decent documented flight before the contest deadline of September 30, 2015.

May 12, 2015
Yesterday morning I decided to give the Rivets a try. I fueled that little Cox .020 and carefully adjusted my panel mounted glow driver and after a handful of flips and priming it fired up and once the needle was adjusted it ran wonderfully. I was so pleased. Well, I opted to let it cool a bit, refueled and figured I'd give it one more check run before hooking up the lines. Wouldn't you know it .... it wouldn't fire!! I did some checking to find that the little glow head had burned out and I didn't have a replacement !! Oh was that frustrating but I s'pose there's always another day .... once I find a replacement glow head!

September 30, 2015
OKAY!!  OKAY!!  OKAY!! I DID IT!!  A couple of days ago I received my order from Cox Int'l for four brand new .020 glow heads and with the flight deadline right on top or me. With the help of my loving wife and a couple of new .020 glow heads, the Rivets finally .... finally got into the air today at 1642 (4:42 p.m. 'fer y'all civilians)  I used some of the last of my Sig 25% and oh man .... what a wonderful sound to hear a full tank run!! I just had to do it a second time just to convince myself that it was really happening! A couple of minutes later it was off to the tarmac where I attached the little thing to my inverted stooge.

I worked with my wife to get her cell phone camera setup because for some reason my Kodak Easyshare DX6340 just wouldn't stay powered up. Nevertheless, when she was ready I handed her the stooge release line, fired up the Rivets and I ran out to the grab the handle. This process had to be repeated a couple of times because the needle setting seemed to vary significantly and intermittently thus reducing the takeoff power. However, the third try was a charm! In about 8 feet, she lifted off quite smartly. What a joy to see it in the air!!

Then ... in a flash .... in the twinkling of an eye .... it was heading into an uncommanded wing over!! Just then, I saw the 35' of .008"steel cables dangling with the little bird heading towards me at full power!! I ran backwards then tried to run to an upwind position and get the lines tight but to no avail! The Rivets was down  (thank goodness for thick grass)!! A sense of doom and horror gripped my mind, my heart pounded, my eyes began to cloud up!! I went over to see my little gem, expecting to see the worse but to my surprise and amazement, there was no damage .... other than to my pride Embarassed

Well, I gently picked the precious little thing up, and carried it back to the pit area where I cleaned her up and made a joyful noise!! THE RIVETS FLEW!! I/We made the deadline and lived to fly another day!! Next time, I'll be using some shorter lighter lines.
(p.s.: I know, I know !! My wife thinks there's something wrong with me too) lol!












Last edited by modelbuilder49 on Fri Oct 02, 2015 10:01 am; edited 1 time in total (Reason for editing : No pictures!)
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Re: The .020 Rivets

Post  batjac on Fri Oct 02, 2015 1:32 pm

Awesome! Great job on the Rivets!

The Impressed Mark
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Re: The .020 Rivets

Post  fredvon4 on Sat Oct 03, 2015 10:28 am

Got too busy to participate this year myself. I really like the different ways you guys come up with a design, build and fly the planes

This one is very cool and a great read on how it came together

Thanks for posting modelbuilder49
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Re: The .020 Rivets

Post  getback on Sun Oct 04, 2015 7:11 am

Good Job !!! modelbuilder49 that was a really nice write up on the build / fly . Nice looking little plane there man , its always testy on that first flight not knowing for sure what will happen . Glad you got it done and had some fun and excitement lol! Eric Very Happy
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Re: The .020 Rivets

Post  ARUP on Thu Dec 10, 2015 8:47 pm

I love your 'Rivets'! I think I saw it on another forum(?). It is one of my favorite Formula 1 jobs and I have a 1/4" scale Quay Barber fiberglass fuselage and foam wing kit of it that I really need to build.
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Re: The .020 Rivets

Post  Cribbs74 on Fri Dec 11, 2015 4:33 pm

Good job on the little Rivets, looking through your pictures I didn't notice any tip weight on the outboard wing. That would most certainly cause your plane to fly into the circle. Being that it only weighs 3.3oz any wind at all would certainly compound the problem.

The .020 Pee Wee takes some fiddling to set up right and a fluctuating needle isn't normal. You may need to replace the spring with a washer and fuel tubing to get a good seal. If that doesn't work then the tank needs to be opened up to check for leaks.

Also, 35' steel lines is probably a bit too heavy and long for a plane that size. I would drop down to 25' and spectra lines. Up to you though.

Good job seeing the project through and I hope we can see some more pictures or video in the future.

Ron
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Re: The .020 Rivets

Post  modelbuilder49 on Sat Dec 12, 2015 2:13 pm

Thanks for the kind words everyone. As I write this I haven't had a chance to fly it again. I've been pouring my attention into completing the build of an 83" w/s B-29 using 4 ea. OS 25's with 4 bladed props. I agree the 35' steel lines are probably far too much for the little thing but I did make a 25' set of 15# Power Pro lines. As for tip weight, yes, I "built-in" about 1/8 ounce of lead into the outboard wing before covering the wing.

Jim
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