Author Topic: Skyray 35 Triplets (Read 15574 times)

realSteveSmith · « **on:** October 16, 2024, 09:15:09 PM »

FAIR WARNING: This first post has little to no building related content. It's more of an intro to my project, and for whatever reason, I wanted to explain why I was endeavoring to build 3 Skyrays. Most of you will probably want to skip right to my 2nd post where I start making some parts. But, if you like reading....there's lots of words down there, so have at it.

I noticed there wasn't an active Skyray 35 build thread. I'm just getting started on a build of my own and I thought it might be fun to keep track of it here. I know this is the 'building techniques' section but I don't expect I'll be teaching anything to anyone. These are simple airplanes and I can't imagine I'll be using any tricks that most of the old hands around here haven't already pulled off dozens of times. The main reason I'm posting here is to help hold myself accountable for finishing these airplanes. I've found that professing my desire to complete a task, in front of everyone on the internet, tends to motivate me to follow through. So....why am I building 3 Skyray 35s anyway?

A bit of background is in order. I got interested in C/L stunt late last summer ('23). I was mainly attracted to the idea of contest flying as I'm the type that has always enjoyed organized competition. I found this site and after some research, I elected to start with a Ringmaster 576 kit from Pat Johnston. As I was building on that, one of my fellow club members (Dan McEntee) was kind enough to connect me with someone leaving the hobby and I ended up with a turnkey Brodak P-40 with an OS LA46. Dan suggested that I buy several of the airplanes that this guy was selling, but I was only interested in the P-40 so I passed on the others. As it turns out, ignoring this piece of advice was not a wise move. LOL

On my first trip to the field with the P-40, Dan got that airplane trimmed/tuned for me and I made 3 fairly successful flights with it. However, when taking off for flight number 4, I managed to hook the up line on a clump of tall grass, and as you all know, things got ugly. The airplane was damaged to the degree that I was unwilling to repair it. Since I wasn't smart enough to heed Dan's advice, 1 airplane had become NO airplanes and I was dead in the water. As mentioned, this was late in the season so I just kind of reconciled myself to finishing that RM576 before I flew again.

Over the Winter, I kept working on the RM576 and got the airplane to about 90% complete. But when Spring rolled around, I found myself pulled in another direction and I put my C/L stunt aspirations aside for other hobbies. I kept reading here on Stunthangar.....I enjoyed seeing Stunt News when it came each quarter.....I watched some of the hangouts....but there was no further building and no flying at all this Spring/Summer. I had fun over the Summer but part of me regretted the fact that I was no closer to flying in a Stunt contest. Now that building season is back, I'm determined to do what I can to change that.

While reading Stunthangar this past Summer, I started to encounter threads about the Skyray 35/OS 25LA combo, popularized by Brett Buck. I like the idea that this combination is reported to be easy to build/trim/tune. I REALLY like that idea that if 'the formula' is followed, the combination will perform in a manor that lets someone learn the pattern without learning any bad habits to compensate for the airplane or engine. I noticed another recurring theme in what Brett suggests when it comes to learning with the Skyray..... don't show up with just 1....build several. Seems like I've heard that type of advice somewhere before.

I've decided to save the RM576 for a time when I can competently fly the pattern. For now, I think my progress will be best served with a fleet of Skyrays.

Time to get to work...

realSteveSmith · « **Reply #1 on:** October 16, 2024, 10:06:32 PM »

Since I wasn't able to buy an authentic Sig Skyray 35 kit, I'm building from plans. I'm choosing to forego 'easy to repair' in exchange for 'easy to replace'. In that vane, I'm spending some time now making a few jigs/fixtures that let me make parts more quickly. I'm also going to be building a D-tube style wing instead of Sig's open framework.

I like the Brodak/Pat Johnston style of wing jig. I decided to incorporate the wing rod holes into a jig that lets me make consistent/symmetrical ribs. The jig pictured below uses short sections of 2016 arrow shaft (5/16" OD) to locate the rib stock while the shape is cut, lead out clearance slots located and spar notch cut. Sharpened brass tubing is used to make clean holes in the balsa.

I use the upper jig plate as a template to cut holes in the rib stock. In this case, I'm using 5/16" OD brass tubing in my hand drill.

Then, the rib stock is placed on the locating pins of the lower jig plate.

I then slide the upper plate on the locating pins, cut half of the rib outline, cut the spar notch and use the larger brass tube (3/8" OD) to cut the ends of the lead out clearance slots. In the photo, I've completed this and have removed the upper plate to show the completed cuts/holes. At this point, I remove the stock, flip it over, and repeat for the other side of the rib outline. In theory, you could leave the stock in place and simply flip the upper plate, but being right handed, I prefer making all the cuts from the same side and in the same direction on the template.

All that's left at this point is to use a straight edge and xacto to complete the lead out clearance slots.

There are 19 ribs per wing. Here are 3 full sets...ready to go. My template leaves the spar notch slightly undersized. Before building I will stack them on the jig rods and use a piece of spar material with adhesive sandpaper on the bottom only to bring the notches to final size.

I made a jig just for the Skyray wing. I used a $12 piece of Melamine shelf board (surprisingly flat) for the base, 1/8" ply for the rod holding stations. I've transferred the rib locations from the plans on to the Melamine base to help with rib alignment during the build. As mentioned above, the rods are Easton 2016 Aluminum arrow shafts. In order to build a full span wing, each rod is comprised of 2 arrow shafts, joined in the center with appropriately sized brass tube and hot-melt glue.

The jig rod holding stations allow clearance for the spars and leading edge sheeting (slot to the lower left side). On this jig, I install ribs, spars, leading edge and sheeting, then flip the wing and install the sheeting on the other side along with shear webs. I've had good luck with wings remaining warp free when removed from the jig after this process.

That's all for now.

Colin McRae · « **Reply #2 on:** October 17, 2024, 08:25:17 AM »

Looks to be a great project.

I recently built one Skyray 35 from a SIG kit, but I did incorporate most of Brett's suggested design mods, with a few of my own (wing tip adjustable weight box and adjustable lead outs added).

I run mine with an OS 25LA and APC 9-4 prop and also started with Brett's basic trim suggestions. CG and lead-out locations, etc.

I can't do the full pattern as yet but an experienced friend of mine flew it and did the full pattern. It pretty much flew quite well right out of the box.

Good luck on your project!

john e. holliday · « **Reply #3 on:** October 17, 2024, 08:34:17 AM »

The old DOC here really likes what you are doing. I will be watching this as you go along. Also if you see Dan again tell him the old DOC says hi.

realSteveSmith · « **Reply #4 on:** October 17, 2024, 04:10:05 PM »

Quote from: Colin McRae on October 17, 2024, 08:25:17 AM

Looks to be a great project.

I recently built one Skyray 35 from a SIG kit, but I did incorporate most of Brett's suggested design mods, with a few of my own (wing tip adjustable weight box and adjustable lead outs added).

I run mine with an OS 25LA and APC 9-4 prop and also started with Brett's basic trim suggestions. CG and lead-out locations, etc.

I can't do the full pattern as yet but an experienced friend of mine flew it and did the full pattern. It pretty much flew quite well right out of the box.

Good luck on your project!

Hi Colin,

I saw your build thread on here. Seems like yours turned out nicely.

I'm using a tip weight box and adjustable lead out guides on mine too.....both are laser cut setups from Pat Johnston.

Thanks for the well wishes -SS

realSteveSmith · « **Reply #5 on:** October 17, 2024, 04:11:47 PM »

Quote from: john e. holliday on October 17, 2024, 08:34:17 AM

The old DOC here really likes what you are doing. I will be watching this as you go along....

Thanks DOC. Stay tuned....I hope to keep this thread going right up to the point that I start flying them.

realSteveSmith · « **Reply #6 on:** October 17, 2024, 05:15:54 PM »

I decided to knock out the tail parts next. It seems like many folks up-size the empennage material from 1/8" to 3/16". This seemed like a good idea to me. I've seen some discussion on modifying the tail on this airplane but, I decided that from my purposes, the stock outlines (i.e. I didn't enlarge the elevator, etc) would be the best move. This should be a pretty simple job and for the most part, it was. There was one slight SNAFU, however....

I was bound and determined to make each tail from a single sheet of 3/16 x 3 x 36 and as you see below....it doesn't quite fit.

I ended up piecing the fin together from 3 smaller parts. This meant a bit of extra time fitting and gluing but it wasn't really a big deal.

All's well that ends well. Here are 3 sets of Skyray 35 empennage. Later on, I'll hinge, bevel, round the edges, etc.

That's all for now.

Colin McRae · « **Reply #7 on:** October 18, 2024, 10:38:23 AM »

Quote from: realSteveSmith on October 17, 2024, 04:10:05 PM

Hi Colin,

I saw your build thread on here. Seems like yours turned out nicely.

I'm using a tip weight box and adjustable lead out guides on mine too.....both are laser cut setups from Pat Johnston.

Thanks for the well wishes -SS

This is interesting. And I'm somewhat of a rookie builder. Based on some simple engineering moment calcs, I moved my OS 25LA (w/ stock OS muffler) engine back a bit since the LA engine w/ muffler is heavier than a Fox 35. I also increased the stab/elev thickness to 3/16". My wing is monocoated and I used Brodak butyrate dope to finish. With that said, my model CG balanced quite well without having to add tail weight. Guess I got lucky.

Then a friend of mine (expert builder) also plan-built a Skyray 35. He did not move his engine back and his also balanced fine.

In any event I liked moving the engine back as it made the front end look a bit better. If not moved back, the prop area would have stuck out quite a bit past the nose. But I guess one could also add a bit of balsa to the nose area to clean up the look.

Paul Smith · « **Reply #8 on:** October 18, 2024, 02:04:41 PM »

I have built three Sig Skyrays. Even with the LA 25, the nose needed to be shortened or else carry A LOT of tail weight.
This is an older pitcher, before I went to the LA 25.
I flew this several times yesterday. Full pattern stunt, but faster than the judges like.

realSteveSmith · « **Reply #9 on:** October 18, 2024, 03:04:30 PM »

Quote from: Colin McRae on October 18, 2024, 10:38:23 AM

This is interesting. And I'm somewhat of a rookie builder. Based on some simple engineering moment calcs, I moved my OS 25LA (w/ stock OS muffler) engine back a bit since the LA engine w/ muffler is heavier than a Fox 35. I also increased the stab/elev thickness to 3/16". My wing is monocoated and I used Brodak butyrate dope to finish. With that said, my model CG balanced quite well without having to add tail weight. Guess I got lucky.

Then a friend of mine (expert builder) also plan-built a Skyray 35. He did not move his engine back and his also balanced fine.

In any event I liked moving the engine back as it made the front end look a bit better. If not moved back, the prop area would have stuck out quite a bit past the nose. But I guess one could also add a bit of balsa to the nose area to clean up the look.

Hi Colin,

What fuel tank did you end up using? There doesn't seem to be a lot of real estate on the stock length nose.....I would anticipate an issue if it were shortened, but it doesn't sound like it caused you any problems.

-SS

realSteveSmith · « **Reply #10 on:** October 18, 2024, 06:25:20 PM »

Quote from: Paul Smith on October 18, 2024, 02:04:41 PM

I have built three Sig Skyrays. Even with the LA 25, the nose needed to be shortened or else carry A LOT of tail weight.
This is an older pitcher, before I went to the LA 25.
I flew this several times yesterday. Full pattern stunt, but faster than the judges like.

I like your wing mounted landing gear. I find I prefer the look of that over anything mounted to the fuse. That being said, I think I'll save a mod like this for further down the road when I'm not making so many airplane shaped holes in the ground.

Colin McRae · « **Reply #11 on:** October 18, 2024, 07:57:48 PM »

Quote from: realSteveSmith on October 18, 2024, 03:04:30 PM

Hi Colin,

What fuel tank did you end up using? There doesn't seem to be a lot of real estate on the stock length nose.....I would anticipate an issue if it were shortened, but it doesn't sound like it caused you any problems.

-SS

I normally run uniflow design thanks on my models for the engine run benefits they offer. I don't have the skills to build my own tanks, so I normally use and purchase Brodak oval profile uniflow tanks. The Brodak oval profile design is the shortest of the tanks they offer for a specific volume. However, the Brodak stock oval profile tank has the fuel pickup on the top which does not work well for a profile model. Tubing routing is not efficient to the spray bar.

Upon request, I had Brodak build me a custom tank. On my Skyray, I ordered a 3 oz oval profile uniflow tank, but I had Brodak simply move the fuel pickup tube to the bottom of the tank. If I remember correctly, it was an additional $3 for the custom modification.

Even with moving my engine back, there was enough room for the 3 oz tank and landing gear. But it was tight.

Brodak's 3 oz tank did fit, but an even shorter 2.5 oz tank is probably sufficient for the full pattern.

BTW, I made my own simple aluminum landing gear for 2 wheels. I'm not a fan of a single center wheel.

realSteveSmith · « **Reply #12 on:** October 19, 2024, 08:02:13 PM »

Wrapping lines and lead outs is probably one of my least favorite parts of Control Line so far. But...it has to be done.

Today, I turned this....

...into this.

That's all for now.

realSteveSmith · « **Reply #13 on:** October 19, 2024, 08:11:27 PM »

Quote from: Colin McRae on October 18, 2024, 07:57:48 PM

I normally run uniflow design thanks on my models for the engine run benefits they offer. I don't have the skills to build my own tanks, so I normally use and purchase Brodak oval profile uniflow tanks. The Brodak oval profile design is the shortest of the tanks they offer for a specific volume. However, the Brodak stock oval profile tank has the fuel pickup on the top which does not work well for a profile model. Tubing routing is not efficient to the spray bar.

Upon request, I had Brodak build me a custom tank. On my Skyray, I ordered a 3 oz oval profile uniflow tank, but I had Brodak simply move the fuel pickup tube to the bottom of the tank. If I remember correctly, it was an additional $3 for the custom modification.

Even with moving my engine back, there was enough room for the 3 oz tank and landing gear. But it was tight.

Brodak's 3 oz tank did fit, but an even shorter 2.5 oz tank is probably sufficient for the full pattern.

BTW, I made my own simple aluminum landing gear for 2 wheels. I'm not a fan of a single center wheel.

It's undoubtedly the 'RC guy' in me, but I really don't like the metal tanks. I don't have a good reason to feel that way....but I just do. That being said, you can have a metal tank in just about any size or shape you want (presuming you can build it or know someone who can) and I can see that being a real advantage. The plastic tanks don't come in nearly the variety sizes. I do have some 90cc (3oz) plastic tanks that I bought from Hobby King a while back. They would probably fit if I elected to shorten the nose. At this point, I'm inclined to leave it stock, however.

Like you, I will also be using conventional gear instead of the mono wheel. I'll probably bend something up out of music wire.

Paul Smith · « **Reply #14 on:** October 19, 2024, 08:41:03 PM »

Making metal tanks is something of a skill and it requires some tools.

But it sure beats searching the world for a factory tank that doesn't really fit the plane and run right.

Kermit Payne · « **Reply #15 on:** October 21, 2024, 07:08:50 AM »

I'm late to the party here, Steve, bit I am enjoying watching the construction. A question about your jig: What keeps the jig rod holding stations from slipping in their holders? Is it just a friction fit, or is there some other ingenious way of keeping them from inadvertently slipping?

realSteveSmith · « **Reply #16 on:** October 21, 2024, 07:42:58 AM »

Quote from: Kermit Payne on October 21, 2024, 07:08:50 AM

I'm late to the party here, Steve, bit I am enjoying watching the construction. A question about your jig: What keeps the jig rod holding stations from slipping in their holders? Is it just a friction fit, or is there some other ingenious way of keeping them from inadvertently slipping?

Hi Kermit,

The rod holding stations are glued together. Rather than butt glue the bottom of the upright to a 1 piece base plate (and perhaps have to deal with adding a fillet. etc) I elected to split the base plate and attach each half to the sides of the upright. Hope that answers your question.

-rSS

Brett Buck · « **Reply #17 on:** October 21, 2024, 09:27:42 AM »

Looks like a great project. Later I will show you my rib-cutting jig - and it will look pretty familiar! Most of what you have shown here is as good or better than the original all-balsa rebuild from ~30 years ago and certainly much better than it looks after 3-4 major rebuilds.

I actually have a new one under construction, too. After I gave the other one away, I found it too useful to go without, so I am making another one with a few changes to make up for the available materials and *a lot* more care, since the original design/construction/finishing of the rebuild took a grand total of about 4 hours - a Monday afternoon when I was on graveyard shift.

I can also report that the original is still at work, yesterday winning Advanced at Golden State at the hand of Zack Shulz, from not able to fly inverted to a 500 point pattern no appearance points from Nationals judges (Joan Cox (just back from judging the WC...) and yours truly) in about 2 years, As previously mentioned in another thread, having a properly trimmed airplane and youthful adaptability, he has never learned to make mistakes while trying to fly questionable airplanes with mediocre or counterproductive power. And he beat his dad quite handily.

Brett

Colin McRae · « **Reply #18 on:** October 21, 2024, 09:28:09 AM »

Quote from: realSteveSmith on October 19, 2024, 08:11:27 PM

It's undoubtedly the 'RC guy' in me, but I really don't like the metal tanks. I don't have a good reason to feel that way....but I just do. That being said, you can have a metal tank in just about any size or shape you want (presuming you can build it or know someone who can) and I can see that being a real advantage. The plastic tanks don't come in nearly the variety sizes. I do have some 90cc (3oz) plastic tanks that I bought from Hobby King a while back. They would probably fit if I elected to shorten the nose. At this point, I'm inclined to leave it stock, however.

Like you, I will also be using conventional gear instead of the mono wheel. I'll probably bend something up out of music wire.

One other thing I forgot to mention. I made my tank height adjustable to have the option to get equal lap times inverted. My tank centerline on the OS 25 LA is 1/8" above the center of the spray bar. I have 3 other models with the 25 LA and they also are at the same 1/8". So maybe a good starting point for your project.

Brett Buck · « **Reply #19 on:** October 21, 2024, 09:37:10 AM »

Quote from: realSteveSmith on October 19, 2024, 08:11:27 PM

It's undoubtedly the 'RC guy' in me, but I really don't like the metal tanks. I don't have a good reason to feel that way....but I just do. That being said, you can have a metal tank in just about any size or shape you want (presuming you can build it or know someone who can) and I can see that being a real advantage. The plastic tanks don't come in nearly the variety sizes. I do have some 90cc (3oz) plastic tanks that I bought from Hobby King a while back. They would probably fit if I elected to shorten the nose. At this point, I'm inclined to leave it stock, however.

Like you, I will also be using conventional gear instead of the mono wheel. I'll probably bend something up out of music wire.

Mine uses .050" 7075 Twhatever gear, an old Hallco RC "fuse bottom" gear, cut in half and bent the other way to go up against the fuse sides. Originally it used the landing gear from a SIG Phazer, either was fine and the new one will probably have the SIG Pazer gear again.

Clunk tanks work *ok*, that what is on the "small engine test" Skyray, but it has some negative characteristics, in particular, it won't cut off cleanly. If you do build a metal tank, make it no more than 1 1/2" wide from the base to the peak of the wedge, because any wider and it will have too much trouble sucking the fuel "uphill" from the outer edge of the tank. Put the clunk tank flat against the fuse just like it shows on the plans. I set my tank up for either uniflow or suction but run it on suction with muffler pressure.

Brett

realSteveSmith · « **Reply #20 on:** October 21, 2024, 10:33:09 AM »

Quote from: Brett Buck on October 21, 2024, 09:37:10 AM

...Clunk tanks work *ok*, that what is on the "small engine test" Skyray, but it has some negative characteristics, in particular, it won't cut off cleanly.

Hi Brett,

Have you ever tried one of these Dubro Tank Filters as the pickup in a plastic clunk tank?

So far, I've only used this in one CL airplane (the ill fated P-40) but it seamed to provide a clean shut off in a plastic tank...and emptied every last drop as well. I got turned on to this type of fuel pickup (there are several varieties) while flying RC helicopters. These types of pickups are also used in RC car tanks to minimize air in the lines and help pickup up fuel as the car (and tank) are bouncing around.

Kermit Payne · « **Reply #21 on:** October 21, 2024, 10:53:27 AM »

Quote from: realSteveSmith on October 21, 2024, 07:42:58 AM

Hi Kermit,

The rod holding stations are glued together. Rather than butt glue the bottom of the upright to a 1 piece base plate (and perhaps have to deal with adding a fillet. etc) I elected to split the base plate and attach each half to the sides of the upright. Hope that answers your question.

-rSS

Question answered, Steve. Many thanks!

Richard Fleming · « **Reply #22 on:** October 21, 2024, 01:22:28 PM »

Thats a great idea for scratch building the wing and the wing jig. Looking forward to your progress!

realSteveSmith · « **Reply #23 on:** October 21, 2024, 01:32:07 PM »

Quote from: Brett Buck on October 21, 2024, 09:27:42 AM

Looks like a great project. Later I will show you my rib-cutting jig - and it will look pretty familiar! Most of what you have shown here is as good or better than the original all-balsa rebuild from ~30 years ago and certainly much better than it looks after 3-4 major rebuilds.

I actually have a new one under construction, too. After I gave the other one away, I found it too useful to go without, so I am making another one with a few changes to make up for the available materials and *a lot* more care, since the original design/construction/finishing of the rebuild took a grand total of about 4 hours - a Monday afternoon when I was on graveyard shift.

I can also report that the original is still at work, yesterday winning Advanced at Golden State at the hand of Zack Shulz, from not able to fly inverted to a 500 point pattern no appearance points from Nationals judges (Joan Cox (just back from judging the WC...) and yours truly) in about 2 years, As previously mentioned in another thread, having a properly trimmed airplane and youthful adaptability, he has never learned to make mistakes while trying to fly questionable airplanes with mediocre or counterproductive power. And he beat his dad quite handily.

Brett

Thanks for the compliment....I'm looking forward to seeing/hearing how your newest version works out. Post some pics of your rib jig....I'm curious how you set it up.

Hearing about Zack (I didn't know his name at the time) is what inspired me to head in this direction. I'm not in my mid 20s so I may lack his 'youthful adaptability' but I still think having an honest airplane/power plant is the best move. I don't have any nostalgic connections to the olden days (no offense to those who do) so I just want what's best for purpose right now, in 2024.

realSteveSmith · « **Reply #24 on:** October 21, 2024, 01:40:27 PM »

Quote from: Richard Fleming on October 21, 2024, 01:22:28 PM

Thats a great idea for scratch building the wing and the wing jig. Looking forward to your progress!

Thanks Richard!

john e. holliday · « **Reply #25 on:** October 21, 2024, 03:27:39 PM »

I just had to back and look at the wing jig. You must be an engineer to do all this good design.

realSteveSmith · « **Reply #26 on:** October 21, 2024, 04:50:53 PM »

Quote from: john e. holliday on October 21, 2024, 03:27:39 PM

I just had to back and look at the wing jig. You must be an engineer to do all this good design.

Thanks Doc, but to be clear, this definitely isn't my design. I'm simply repurposing concepts that I've seen elsewhere.

The first time I saw these principles in use was with the good ole A-justo-jig. They may not have been the first but that's where i first saw a 'wing rod' type jig. There are folks all over Stunthanger using these. I know Dennis Nunes employed a jig like this on his 'Circulas' designs. Great Planes had a jig like this. Brodak sells a jig like this. Pat Johnston designs all his airplanes for and sells a jig like this. I'm sure there are many more. Credit goes to all these folks....I just copied what I saw and tailored it to this Skyray project.

realSteveSmith · « **Reply #27 on:** November 02, 2024, 07:27:04 PM »

I spent some more time on the Skyray project this week. Here is how that went...

Conventional wisdom is that, when scratching building, you cut out a full 'kit' of parts first....then build the airplane. That being said, I'm still a bit undecided on how to approach making jigs/parts for the fuse. Somewhere I saw pics of the stock Sig kit and the fuselage appears to be split down the middle, length-wise, through the wing saddle/cut out. This appeals to me because, while I do have a nice band saw, I don't have a scroll saw. I expected I would need to buy one at some point to complete the wing cutout on this fuse(if going the 1 piece route), but the 2 piece approach would let me use my band saw. Since I haven't decided on how to tackle the fuse jig and parts, I decided to frame up a wing, instead...HA!

I wanted to use 1/4" square balsa for the spars. Can we talk about how hard it is to find straight balsa sticks these days? I tried both my local hobby shops and even a couple hobby lobby stores. Nothing but warped wood as far as the eye can see. So, I decided to make my own from a nice straight grained 8lb piece of 1/4 x 3 x 36 sheeting....with a Master Airscrew balsa stripper. Of course the pieces needed to be longer than 36" so I used 20 degree scarf joints and a 48" piece of angle aluminum from the hardware store to make some nice straight, loooong spars. Rather than center the joints, I offset them as far as I can towards the tips. The joints end up in the 3rd rib bay from the tip, on opposite ends top vs bottom.

Next the ribs are installed on the rods. I use 1-2-3 blocks and the lines I made on the base plate earlier, to ensure the ribs are square and spaced properly.

In this pic, I've installed a spar and the first piece of 1/8 x 1 x 48 leading edge. The blue tape serves to protect the ribs while I shape the leading edge.

The goal is to match the rib contour when carving the leading edge. This provides support/gluing surface for the front of the leading edge sheeting. After the LE sheeting is installed, it is trimmed to be flush with the 1/8th leading edge. Later, a second piece of 1/8 leading edge is laminated to the first and the final contour is carved. For now, it ends up looking something like this.

Next comes the first piece of 1/16 x 1 1/2 trailing edge sheeting.

Once I had the back of the ribs stabilized with the first piece of TE sheeting, I flipped the wing over and installed the 2nd spar. Then I carved the other side of the 1/8 leading edge to match the rib contour. I installed both LE and TE sheeting on this side of the wing....this pic is after all that has been completed.

All that was left was to flip the wing in the jig again (good thing this is simple/easy) and install leading edge sheeting on the remaining side of the wing. I then pulled the wing off the jig to go over all the joints with thin CA. I like using gravity to send the glue where I want it and keep it from going where I don't want it.

In person, I could see that, even without any of the shear webbing, the wing is very straight/true. The shadows in the picture might make it tougher for you to see...so you'll have to trust me. LOL

At this point, I'll set this one aside and frame up 2 more. Later, I'll put the wings back in the jig to install the bellcranks, shear webs, cap strips and one side of the center section sheeting. I also use the jig to hold the wing while I sand the final shape of the leading edge and I'll show you that too.

That's all for now.

realSteveSmith · « **Reply #28 on:** November 02, 2024, 08:09:30 PM »

One more thing.....

This isn't specifically a build update but it does pertain to the Skyrays...

I was about ready to order parts to build a 3rd 25LA (I only had 2) when I came across the OG of BBTU engines. A NEW IN BOX FP20! How could I resist?

John Skukalek · « **Reply #29 on:** November 02, 2024, 08:37:09 PM »

great looking work Steve

realSteveSmith · « **Reply #30 on:** November 02, 2024, 09:05:25 PM »

Quote from: John Skukalek on November 02, 2024, 08:37:09 PM

great looking work Steve

Thanks John!

Brett Buck · « **Reply #31 on:** November 02, 2024, 09:46:14 PM »

Referring to earlier posts - you do not need to shorten the nose. My rebuilt model is feather light, has a 25LA with the STOCK MUFFLER, and a spinner. I have had the CG all over the place but last I measured it was 1 1/8" from the LE with no extra balance weight. Unlike flapped airplanes he it is very insensitive to the CG, it has lots of tail volume, and you can move it to change the response without it becoming unstable. Further aft, it gets more sensitive around neutral and then slows down, further forward, it is insensitive around neutral and accelerations with deflection.

I do not say that 1 1/8" is some magic setting that is optimal. But almost everyone's airplane will be heavier than my rebuilt model, heavier moves the CG back, so I don't think there is any reason at all to try to shorten the nose. And they are generally light enough that adding weight won't hurt anything.

Brett

Paul Smith · « **Reply #32 on:** November 03, 2024, 06:15:39 AM »

That being said, I'm still a bit undecided on how to approach making jigs/parts for the fuse. Somewhere I saw pics of the stock Sig kit and the fuselage appears to be split down the middle, length-wise, through the wing saddle/cut out. This appeals to me because, while I do have a nice band saw, I don't have a scroll saw. I expected I would need to buy one at some point to complete the wing cutout on this fuse(if going the 1 piece route), but the 2 piece approach would let me use my band saw. Since I haven't decided on how to tackle the fuse jig and parts, I decided to frame up a wing, instead...HA!

In this pic, I've installed a spar and the first piece of 1/8 x 1 x 48 leading edge. The blue tape serves to protect the ribs while I shape the leading edge.

The goal is to match the rib contour when carving the leading edge. This provides support/gluing surface for the front of the leading edge sheeting. After the LE sheeting is installed, it is trimmed to be flush with the 1/8th leading edge. Later, a second piece of 1/8 leading edge is laminated to the first and the final contour is carved. For now, it ends up looking something like this.

Next comes the first piece of 1/16 x 1 1/2 trailing edge sheeting.

Once I had the back of the ribs stabilized with the first piece of TE sheeting, I flipped the wing over and installed the 2nd spar. Then I carved the other side of the 1/8 leading edge to match the rib contour. I installed both LE and TE sheeting on this side of the wing....this pic is after all that has been completed.

All that was left was to flip the wing in the jig again (good thing this is simple/easy) and install leading edge sheeting on the remaining side of the wing. I then pulled the wing off the jig to go over all the joints with thin CA. I like using gravity to send the glue where I want it and keep it from going where I don't want it.

In person, I could see that, even without any of the shear webbing, the wing is very straight/true. The shadows in the picture might make it tougher for you to see...so you'll have to trust me. LOL

At this point, I'll set this one aside and frame up 2 more. Later, I'll put the wings back in the jig to install the bellcranks, shear webs, cap strips and one side of the center section sheeting. I also use the jig to hold the wing while I sand the final shape of the leading edge and I'll show you that too.

That's all for now.
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One way to cut the wing hole with a band saw or jig saw is to enter from the front between the engine mounts. The excess slot is then plugged with balsa of the necessary thickness. The cut will be buried under the plywood doublers and it won't weaken the plane of be noticed.

realSteveSmith · « **Reply #33 on:** November 03, 2024, 06:44:32 AM »

Quote from: Brett Buck on November 02, 2024, 09:46:14 PM

...Referring to earlier posts - you do not need to shorten the nose...

Duly noted.

realSteveSmith · « **Reply #34 on:** November 03, 2024, 06:50:12 AM »

Quote from: Paul Smith on November 03, 2024, 06:15:39 AM

..One way to cut the wing hole with a band saw or jig saw is to enter from the front between the engine mounts. The excess slot is then plugged with balsa of the necessary thickness. The cut will be buried under the plywood doublers and it won't weaken the plane of be noticed.

Thanks Paul. This is so simple and obvious (like all good ideas), it's no wonder I didn't think of it. LOL

I mentioned in my opening post that I didn't expect to teach anything there. What I didn't mention, is that I DID expect to learn a few things. Looks like I was right. -rSS

john e. holliday · « **Reply #35 on:** November 03, 2024, 05:22:21 PM »

This build is getting my desire to build again going. But I need to finish the flooring in the shop.