Feeling a little guilty…

batjac Mon Jan 09, 2017 12:28 am

I decided that this year I’d get serious about actually learning to fly the AMA C/L pattern. I figured I’d enter Beginner this year, and maybe N-30 next year. So I got the materials to do the Brett Buck Method for learning. Brett’s method is to build three identical Skyray 35 planes so that when you crash one, you just fetch another one from the trunk and keep flying. If you crash that, grab the third and keep going. That way you’re not down until you get another plane ready to fly, and you have time to fix the broke ones before the next outing and you go for it again.

I got a .pdf of the plans from a guy over on Stunthangar, and I’m going to scratch build the three planes, incorporating the things Brett Buck recommends, and a couple of other things I want in them. I don’t need the full plans, just the fuselage profile and the rib templates. The rest I can just draw out on printer paper and cut out, and layout the wing spar to build over on some wrapping paper.

But, I guess I started feeling a little guilty about spending so much time building the .35 sized planes, and neglecting my Cox engines. Kinda like cheating on your girlfriend with the girls the next town over. But, then I thought about the SIG Skyray kit I had in the closet. I don’t want to build anymore slab wing planes. And I sorta told myself I wasn’t going to build any more 1/2A planes until I crash some of the ones I have (too many of). But, I guess I just couldn’t leave well enough alone. So I pulled the Skyray kit out of the closet and pulled off the plastic.

Taking out the printed wing sheet and measuring it, the wing chord is 4.75” and the span is 23.75”. This gives about 110sq.in. of wing area. But, I really didn’t want to build another slab wing. Hmmm…. Well, since I was printing out wing templates for the Skyray 35 which have a 9” chord, I figured I’d just print a reduced template to get a 4.75” wing chord. Voila!

Then I cut out the rib templates and pasted them to the official Batjac Aeroworks template stock.

I popped the Skyray fuselage out of the die cut wood and drew the outline of the fuselage on some paper. Marking a reference line fore to aft on the fuse, I drew the outline of the rib template on the reference line. Then I marked the firewall and figured out where the prop drive plate would be on a Babe Bee engine. From that I worked back from the drive plate of a Medallion and drew in the maple engine bearers, the doublers, and the gear leg. Then I erased and drew, drew and erased, erased and drew until it looked right. Once I was satisfied, I drew the tail surfaces on the sheet.

Next I just drew up the wing on three more sheets, and it’s ready to go.

Presenting the Skyray 110! I plan on starting this as soon as I get the three Skyray 35s done. I just wanted to get it on paper while I was thinking about it.

The Guilty Mark

**Cribbs74** Mon Jan 09, 2017 12:49 am

Mark,

Choose any medium you want. You can fly the pattern on 1/2A if you feel like it. Brett Buck is not the be all end all. People were learning the pattern long before he was a thing.

I am not trying put him down, but it's possible without following his method. I do my own thing and take pointers from friends and accomplished flyers. I catch flack for flying some old airframes and Fox .35's. I can make those old planes do what I want and get a lot of compliments on my engine runs.

I say all that, just to let you know that you can learn a pattern with any competent plane. Slab wingers can even do it, just not very well. I strongly believe that flying is 95% mental and 5% skill.

I think that most people are held back about caring about their builds. Fly like you don't give a hoot and you will progress quickly. You will also crash a lot. It's a good way to thin the herd and with the speed you build it shouldn't hurt too much. That 110 looks good, should make for a decent flyer.

Ron

KariFS Mon Jan 09, 2017 2:16 am

Sounds like a great method having 3 identical (within reason) planes properly trimmed and ready to go. I did that with R/C Slow Sticks as the freezing temperatures made the propellers and especially the motor reduction gears fragile. I had 2 planes ready to go, and after I broke something on one, just grabbed another. Now that I am not completely hopeless, I only use one plane again.

I also agree that slab wing builds get a bit "old". It is fun to create different profiles and paint them but after two or three it kinda repeats itself. For basic training and stunts a thick symmetrical wing is better anyway (or that's what I've been told). I suppose if you get all the jigs and templates ready you can build 3 planes in almost the same time as it takes to build one.

Captain Crunch... Yes, that could be my nickname, based on the sound my planes sometimes make Embarassed

rsv1cox Mon Jan 09, 2017 6:47 am

Capt. Crunch Berries boxes for templates, I failed to grasp the symbolism. Thanks Kari for pointing it out. I got a chuckle. Smile

Nice job Mark.

Bob

getback Mon Jan 09, 2017 7:36 am

Good to hear your going to step up to the beginner pattern , i would personal need two or three plane of the same to get started . This year i just want to get some slower than 65 mph planes with Medallions of TD on them and a JR. size airplane for CL . Heck i have everything sep the time Huh...

Need to get the Glue out i am over due ! Like the way you scaled down the Skyray it looks good so far > Very Happy

pkrankow Mon Jan 09, 2017 8:07 am

Brett Buck has a system that is simply *_more_easily_repeated_* than some other suggestions. In the original form it involves using a box stock common engine, a choice of 3 different engine, all now discontinued.

The current advantage is these engines are still readily available and can be easily converted to the CL version, and plenty are available on Ebay, at shows, and swap meets. Parts to convert can be ordered easily (as of today, January 2017, Tower has all these parts, per their website). Converting a used engine, including muffler, likely costs less than a new engine when they were available. ($30 for good used engine, $25 for muffler, $15 for NVA, $10 for venturi = $80)

FP20
FP25
LA25

The iron lunged FP's have the incorrect muffler for the pipe effect. The front NVA is arguably better than the rear NVA, but both work. The plastic fuel tank is easy to get, and all 3 engines run the same APC 9x4 prop.

The other bit is the ratio of stab to main wing, I believe it is 25% by making the original stab and elevator longer.

That said I can't fly on longer than 35 ft lines in my own yard. I am rather interested in this build.

Phil

Mark Boesen Mon Jan 09, 2017 1:05 pm

Nice build Mark!
I like the idea, always did of having a back-up ready to go, even better, have three ready to go, this totally eliminated any down time in the learning curve and allows you to burn fuel (practice) the best method for learning.
Also, you'll see that a built-up wing takes very little additional time in the total build process and after you fly it, it'll make you wonder why you didn't start building up wings sooner.
Remember, the 1/2a Skyray was designed for a reedie (Black Widow/Babe Bee/Golden Bee etc.) if you're going to use a Tee Dee, you might look at a larger wing, 160 sq. in. or better.

batjac Mon Jan 09, 2017 5:27 pm

Ron, I'm following the Brett Buck Skyray system because it makes sense. It could be three planes of any design. I just chose the Skyray because it's what came up, there’s one at the local field that flies great, and because it's flapless. If Top Flite still made the Flite Streak ARF for $69.00, I'd just buy a couple more and fly those into the ground. But no more. Heck, if they even sold replacement wings, I'd buy a couple or three. I know CoreHouse sells a Flite Streak like wing, but I prefer built up wood to foam. Just a preference. I’m still flying 1/2As across the street for simplicity and brevity, but when I drive across town to fly with the other Fireballs at Delta Park, I take bigger planes. Also, it really does make it easier for me to make consistent shapes when the lines are longer and the laps are slower with the bigger planes. But, really. A Fox .35 on a classic plane? How could you… Shocked

Phil, I have three O.S. .25 LA-S engines. One silver, which I bought new last year and was the last one the local shop got in before they were discontinued. I replaced the remote needle with the venturi needle and the backplate with a .25 FP metal backplate. It’s currently on a Flite Streak ARF. I also got two more used ones cheap that are the blue engines. I got two more needle valves for the venturis, and one O.S. venturi to replace a delrin venturi of unknown origin. Unfortunately, Tower no longer sells the FP metal backplate. I’m tempted to just cut the remote needle bracket off of the plastic backplates and call it good.

Mark, slab wings are actually new for me. I’ve been building balsa built-up wings since the late 70’s, albeit for R/C planes. My first slab wing build was a Beginner’s Ringmaster a little more than three years ago. Then using the SIG airfoil shaped balsa became interesting, too. But I’m about over that kick. For the engine, I was planning on using a Medallion for it rather than a TD. Almost the same numbers as a Black Widow. Although, this might be a good time to try the project of putting a Medallion venturi body on a TD engine. Hmmm… Huh...

The Long Winded Mark

**Cribbs74** Mon Jan 09, 2017 7:28 pm

Hey Mark,

The 3 plane idea is a good one, my intent, though poorly written was to merely convey that if you feel guilty then learn the pattern with a 1/2A.

I totally understand wanting to fly something bigger. I improved quickly when I got hold of a Ringmaster. Are you going with the FP .25 for power?

Ron

roddie Mon Jan 09, 2017 9:15 pm

I can help you out with wood for the "6" airplanes. PM me..

pkrankow Tue Jan 10, 2017 1:13 pm

~~The FP and LA backplates are the same dimensions inside and out. The FP is metal.~~

See Kens post

I am tempted to saw off the NVA on the plastic back LA's too because they are in a bad spot and cannot be moved. If they were in the same corner and rotated the other way, 90 degrees, then the needle would be protected by the cylinder. I made aluminum guards out of some common 1/16 flat aluminum after breaking off a needle. It gets held in by the mounting screws.

If the circle of plastic is not around the screw after breaking off the NVA it may leak air. At least mine did.

The Corehouse RST seems pretty good. I haven't flown mine yet, it will happen this spring or sooner.

Phil

fredvon4 Tue Jan 10, 2017 2:09 pm

Regarding the BBTU... actually "Dirty Dan" Rutherford's initial idea, based on the OS FP (ABC) .20 with the requisite E-2030 Muffler and a an APC 9x4 prop,,,,

Bret Buck's Tune Up (BBTU) is tongue in cheek...basically meaning leave the danged engine alone and follow the (Rutherford) pure recipe, out of the box, for a decent stunt running engine for a LOT of .35 sized airplanes

I have a OS LA 25 on the nose of one Phl Cartier RST, and two more in various stages of finishing right now. One destined for a Iron OS .25 and one will get a true BBTU (AKA Dirty Dan' recipie) OS FP (ABC) .20

If the goal is quick build, near indestructible, and multiple airplane with same or similar engines and set up

I highly recommend the RST...BUY one kit and two extra sets of wings as the other parts are in most of our Bass and Balsa bins already

One of mine has a 3/4 thick Balsa fuselage instead of the Basswood version

The RST built and set up per plan is about the most "fly off the board" plane I ever built... The only "trimming' we did was to set launch RPM higher and shorten lines to 60" from the initial 67" .015s
No tip weight, no fussing with CG from plan, relatively ugly plane, that if DORKED ----does not tork off the builder cuz it is easy to fix

I have a SkyRay and a Twister kit to be copied and then built--- but for now the cheapest and fastest way was the RST

BTW my First RST got a set of Ringmaster tail feathers and some slight wing mod to look RM S-1 ish.---Flew just fine on the 67' lines and 8~12 Mph winds.... I now have about 13 flights on that bird and it suffers my abuse very well...but is one very UGLY airplane....grin

Ken Cook Tue Jan 10, 2017 3:05 pm

I totally disagree with the FP /LA backplate. Curtis Ship offers CNC backplates with a O-ring. We exchanged e-mails early on when I mentioned to him that the metal FP .25 backplate doesn't extend as far into the case as the plastic one does. This isn't the situation with the .40/.46 or .15. The rod can slowly walk off the pin and while it doesn't fall off, it can bind slowing down as if the engine is going rich. I had to lap the backs of the cases to get the metal one to work. Having the plastic is a non -issue, they rarely leak and when they do they're easily repaired by using #4 washers under the screw heads.

Mark Boesen Tue Jan 10, 2017 3:48 pm

I've used plastic backplates (ground off the needle mount) and installed them with small washers and Loc-tite from the get go, never had a problem.

pkrankow Tue Jan 10, 2017 7:42 pm

Ken Cook wrote:I totally disagree with the FP /LA backplate. Curtis Ship offers CNC backplates with a O-ring. We exchanged e-mails early on when I mentioned to him that the metal FP .25 backplate doesn't extend as far into the case as the plastic one does. This isn't the situation with the .40/.46 or .15. The rod can slowly walk off the pin and while it doesn't fall off, it can bind slowing down as if the engine is going rich. I had to lap the backs of the cases to get the metal one to work. Having the plastic is a non -issue, they rarely leak and when they do they're easily repaired by using #4 washers under the screw heads.

Good to know. I am likely in error.

Phil

Ken Cook Wed Jan 11, 2017 4:07 am

Phil, this can be observed with the liner out of the case and the rod and piston on the crank. There have been different runs of cases some from Japan and some from China. This is usually noted on the lug. It can be made to work, just be certain that the play isn't excessive. I personally don't use the needle and saw off the remote bracket. While the needle itself is good quality in terms of a o-ring, the taper is incorrect and just as soon as the engine peaks, it rapidly drops in rpm's as it's starving for fuel. The standard upfront assembly seems to do the job much more reliably and starting is much easier due to the remote wanting to allow the fuel to run back into the tank.

batjac Wed Jan 11, 2017 11:14 pm

Well, I was going to wait to start this, but I’m just so weak. This afternoon I went ahead and cut the ribs for this thing. I drew in some nose ribs on my wing plan like the full size Skyray has. I’m not sure yet if I’ll use them, as I’m not too partial to a bunch of nose ribs. I’ll decide before I finish the wing.

Digging in my box, I found I do have enough 1/8” spruce for the spars on hand. That was the only thing I wasn’t sure about for the build. So when I get back maybe I’ll do this first, then finish off the other three.

I have to fly out first thing in the morning, so I can’t do anymore now.

Ron, I’m going with the LA-S’s for the planes. I half-heartedly looked for .20 FPs, but I was much more interested in the .25 LA.

The Weakling Mark

batjac Mon Feb 27, 2017 12:04 am

Well, I got back to this. I decided to do this before I did the three full size Skyrays. I taped down the wing plan and covered it in plastic wrap. Then it was just a straight forward build from there. I find I like the nose ribs more than I thought I would.

After that, I covered the wing with Sky Blue Monokote. Then I glued everything together and installed all the hardware. It still needs the final trim, but I’ll do that when I finish the other planes. The flight ready plane will have a Medallion instead of a TeeDee, but I just grabbed the first convenient rotary valve engine to drill the mounting holes.

I’ll update when I do the final trim and first flights.

The Long Term Mark

rsv1cox Mon Feb 27, 2017 6:59 am

Such a nice job Mark. That's a whole lot of wing there. The internals are pretty enough to have used transparent monocoat but that sky blue works so well. Way to nice to do a Capt Crunch. Hope you do a flight follow-up.

Bob

pkrankow Mon Feb 27, 2017 7:25 am

Needs trim. Pick up some pin striping tape and have a lifetime supply of it.

Looks awesome, just excessively uniform in color.

Phil

batjac Mon Feb 27, 2017 6:52 pm

Well, I hope not to crunch it. It’d be depressing to break it so soon after finishing it.

Phil, I’m going to do something on these models that I’ve never, ever done on a kit in my 40 years of modelling. I’m going to trim it like the manufacturer did. They’ll look like the picture on the box of the 35 sized Skyray:

The Copycat Mark

pkrankow Mon Feb 27, 2017 8:46 pm

Aluminum duct tape makes pretty good "canopies".
Phil

roddie Mon Feb 27, 2017 8:59 pm

Nice scaling/building-work Mark.

stuntflyr Mon Feb 27, 2017 9:02 pm

Nice looking model.
One thing I would try, is that you might find a longer tail moment helpful for increasing turn rate as well as stability.

I wonder why Don wrote his first post in the way he did; reference, "...since Brett Buck became a thing..."
He just came up with a good way to learn the freakin' pattern. We need people to show up at the contests and have a bit of competitive fun and increase ability even if you don't want or need to win the Nats. If you don't want to it's fine but if you do it's a heck of a good way to keep ones day productiv while learning.
Chris...

pkrankow Thu Mar 02, 2017 7:12 pm

I am borrowing your idea. Not sure if I am going to build it. I found it funny that the Sig Skyray 35 is printed at 53% to produce the desired wing size! I have not double verified my printouts yet.

110 square inches would be suited to a strong reed engine, pretty close to the upper limit for CL stunt on a reed .049.

Phil

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