Scratch builds, material failures, stress testing and the general disorder in my life

[The Hangar]

Maiden flight of my scratch built Mini Scout!

View attachment 181641

Went fairly good. Landed on purpose without damage once, then the wind picked up, and gusts.



Smacked / cartwheeled into the ground twice, then hit a branch when a gust caught it and nose dived into the ground.

View attachment 181642

It messed the front of the plane up. Its easily fixable, the prop is toast. I should have stopped when the wind picked up with gusts.

View attachment 181643

Oh well, it was still fun! I managed 2 loops, on purpose even! It seems to turn left easier than right. I'll work on the settings. I had them limited pretty far to limit the sudden changes until I build some muscle memory.

OH! And I found some 1/8 inch foam at Hobby Lobby, I'm going to use it on the Corsair. So the tiled plans you see in the picture above will have to be adjusted a little for thickness. I am going to try to lighten up the airframe. I have all the guts /linkages etc except a receiver.

Congratulations! The plane will naturally want to turn to the left more than to the right due to the rotation of the motor while it's spinning. The mini Corsair is an awesome plane and one of my favorites - good choice! I highly recommend making it 4 channel though. As far as tips go, make it as light as possible! I used 5g servos and was sparing on the glue, and I used a 500 mah 3s. However I tested it on a 1000 mah 3s pack and it flew terribly, so keep it as light as possible and it will fly amazing.

 

[Stress Test]

So another short flight, SERIOUS left turn due to no right thrust from quick repair. I decided to repair it right and build a new motor pod.

Here is the laid out, with broken prop, and what I did this morning since I can't get to work on the icy roads. 1 hour and 20 minutes to drive 20 miles, 10 out and 10 back.

I cut the torn up sections out and fit a clean foamboard plug back in.

And its ready, minus prop and battery, to fly again! and since I'm home and can't work I am going to start on the patterns for my mini corsair. I have poster board and it make replacement parts so easy to build I'll do it every build from now on.

I'm starting on the mini corsair right wing. I'll post more later.

 

[Stress Test]

Ok So it is cold and snowy out..... What would you do?

Yeah, me too. So i got working on my Mini Corsair 150. Uh, I forgot to mention I scaled it up to 150%, just shy of the size of a Simple Cub. It is the first time I have not built to plans or from kits. Of course that is why I put my thread here!

The raw wing cut out and the insides modified for the larger size. I will wind up with a slightly thicker chord than the Mini Corsair. I am also putting more angle in the center section of the wing and the dihedral will be something like the original F4U.

I made custom squeegee to scrap the glue on the center section, I added a piece of foam board with the paper removed and then packing tape. Its a bit ugly but I believe its strong.

So the (semi) finished wing with another Mini to compare size to. I am stopping here for the day and letting the build process simmer in my mind. The wing is not heavy even with all the pieces and glue in it. Hollowing and thinning bracing parts inside helped.

Is it going to be light enough? Time will tell!

 

[Yusernaym]

That looks great! Your cuts are a lot cleaner than my early attempts at scratch building.

 

[Tech3811]

Yeah, I can tell you are taking your time. Good job, and happy flying! (when the weather persists)

 

[The Hangar]

Ok So it is cold and snowy out..... What would you do?

View attachment 181753

Yeah, me too. So i got working on my Mini Corsair 150. Uh, I forgot to mention I scaled it up to 150%, just shy of the size of a Simple Cub. It is the first time I have not built to plans or from kits. Of course that is why I put my thread here!

The raw wing cut out and the insides modified for the larger size. I will wind up with a slightly thicker chord than the Mini Corsair. I am also putting more angle in the center section of the wing and the dihedral will be something like the original F4U.

View attachment 181754

I made custom squeegee to scrap the glue on the center section, I added a piece of foam board with the paper removed and then packing tape. Its a bit ugly but I believe its strong.

View attachment 181755

So the (semi) finished wing with another Mini to compare size to. I am stopping here for the day and letting the build process simmer in my mind. The wing is not heavy even with all the pieces and glue in it. Hollowing and thinning bracing parts inside helped.

Is it going to be light enough? Time will tell!

View attachment 181756

I love that idea! At 150% it should fly amazing!

 

[Stress Test]

I love that idea! At 150% it should fly amazing!

I'll still crash it, hence the patterns. Also by documenting it here if it does fly forgiving enough for a guy with less than 10 minutes flight time at this point maybe someone else will want to build one.

Truly I plan to get more experience before flying this one. I have a Simple Cub that I have flown twice. I'll be putting it in the air more before I try a model of a low wing fighter plane!

 

[GrizWiz]

I'll still crash it, hence the patterns. Also by documenting it here if it does fly forgiving enough for a guy with less than 10 minutes flight time at this point maybe someone else will want to build one.

Truly I plan to get more experience before flying this one. I have a Simple Cub that I have flown twice. I'll be putting it in the air more before I try a model of a low wing fighter plane!

I can't wait for the new master series mini corsair!

 

[Stress Test]

Trudging - to whit, the weary but determined making of patterns that are the exact material the final product will be and you resist the temptation of using the pattern and saying screw it....

I present a sheeting pattern made of posterboard, to trace onto, well, posterboard, and then cut out again....

And to add insult to injury, the dang canopy pattern could be sprayed black to cover the ink....

I digress.

 

[Stress Test]

Pattern making and first cutout complete! So I have a complet set of foam and posterboard parts. These are to the patterns as drawn except the one upright piece which I hollowed a bit.

I plan to modify the patterns as I build it to match what I do to make it a better 150% build.

NOW! I need the hive mind's input.

I made a pattern for some poster board wingtip fairings. My thought is the smoother airflow is worth the weight. I also plan to learn "ironing" and smooth up the top side of the wing tip.

What does everybody think? And fill me in on the thought process as to why. (remember I am really new to this)

 

[Pieliker96]

As far as I know the undercambered wingtips present on most FT models are there to reduce tip-stall tendencies - a foil with more camber has a higher stall angle of attack than a reduced-camber or symmetrical section. This means that, in a stall, the root of the wing tends to stall before the tips, leaving you with some amount of roll control with the ailerons. Removing the undercamber by flattening out the bottom of the foil leaves you with a cross section similar to that of the rest of the wing, meaning it'll be more prone to drop a wing in stalls and easier to spin - Depending on what you expect of the plane, this can be either positive or negative. That said, this modification would decrease the overall drag of the wing by making it smoother and getting rid of the undercambered section, which, at the Reynolds number's we're talking about, is more draggy than necessary.

TL;DR: The modification would result in less drag and harsher stall characteristics.

 

[Stress Test]

OK, so I have to do other things this afternoon. But I had time a little.

I hollowed out a few parts.

And then I tried ironing on a scrap.

Whoever the first fruitcake was to say, "Hey, I think I'll take an iron to the foamboard ..... " well, they were a genius!

A little ironing, a little sanding and the edge is so much nicer! It's hard to tell in the pic but I did both sides, less on one, and I think the airflow will be much smoother. Guess I'll be ironing all of my builds from now on.

At some point I need to dig through the Master builder series / forum and find all these crazy little tips to improve my builds!

@Pieliker96 -- I need better stall characteristics, not worse, so more drag and open wingtips!

 

[Stress Test]

Ironing foam has made foam aircraft attractive.

Let me explain. I was prejudiced, yup, I thought, foam board? are you kidding me? But hey, it is cheap and knowing I would crash I figured why not.

I used to build peanut scale rubber powered airplanes. They looked better than they flew sometimes, serious attention to detail. I didn't think I would come close to that with foam board. I was wrong.

Just smoothing up a transition on the wing tip made me happy. Before:

And then after, not perfect but little things like this make me feel better about a build.

And the elevator I took some time with, all edges are done on both sides, to varying amounts The round edges of the elevator I just rolled in a little bit. It is surprising how much this stiffen the part.

The weird angle was to get shadows so it showed up better. Notice I left the part that meets the fuselage full height. I haven't decide if I want to blend the notch (red arrow) I am afraid I will mess it up because the iron is so big. I'm looking foe a small iron now. The orange arrow is the leading edge, more slope on the top, less on the bottom. I practiced rolling the edge round but want to make a tool to assist in forming it.

 

[The Hangar]

Ironing foam has made foam aircraft attractive.

Let me explain. I was prejudiced, yup, I thought, foam board? are you kidding me? But hey, it is cheap and knowing I would crash I figured why not.

I used to build peanut scale rubber powered airplanes. They looked better than they flew sometimes, serious attention to detail. I didn't think I would come close to that with foam board. I was wrong.

Just smoothing up a transition on the wing tip made me happy. Before:

View attachment 182452

And then after, not perfect but little things like this make me feel better about a build.

View attachment 182453

And the elevator I took some time with, all edges are done on both sides, to varying amounts The round edges of the elevator I just rolled in a little bit. It is surprising how much this stiffen the part.

View attachment 182454

The weird angle was to get shadows so it showed up better. Notice I left the part that meets the fuselage full height. I haven't decide if I want to blend the notch (red arrow) I am afraid I will mess it up because the iron is so big. I'm looking foe a small iron now. The orange arrow is the leading edge, more slope on the top, less on the bottom. I practiced rolling the edge round but want to make a tool to assist in forming it.

Ironing does make it look a lot better, doesn't it! One added benefit is that you get much more rigidity without adding any weight!

 

[Stress Test]

Ironing does make it look a lot better, doesn't it! One added benefit is that you get much more rigidity without adding any weight!

Yes, and I thought it was stiffer, that angle and thickened foam material around the edge.

Life has been busy, we are trying to buy an RV and should pick it up tomorrow afternoon. One of the trips I am thinking of is a Flite Fest!

OK on another subject, my short video of the Scout got age restricted by Google. I have no idea why. Are model aircraft considered dangerous content? I don't think I have ever seen it on any videos I have watched. If someone here flagged at least tell me why you did.

 

[The Hangar]

Yes, and I thought it was stiffer, that angle and thickened foam material around the edge.

Life has been busy, we are trying to buy an RV and should pick it up tomorrow afternoon. One of the trips I am thinking of is a Flite Fest!

OK on another subject, my short video of the Scout got age restricted by Google. I have no idea why. Are model aircraft considered dangerous content? I don't think I have ever seen it on any videos I have watched. If someone here flagged at least tell me why you did.

Awesome - I'm really looking forward to Flite Fest this next year!

I have no idea why. It's never happened to me, but then again I only use youtube for sharing vids...

 

[Stress Test]

11 Days it took me to escape the Bermuda Triangle, but I'm back!

Actually, we bought an RV. And it took some time, but it also needs some work.

Its a Diesel Pusher, a 1993 Firan Covington 34 foot with a 5.9 Cummins and it looks like this:

Then we started cleaning, and this happened:

For a full description and build thread follow this link. Oh and this will be my traveling build center for a Flight Fest if the world doesn't explode in 2021. Hench it's inclusion here.

We bought vinyl flooring, sub floor and carpet today. That's not in the other thread yet.

And so that brings me to today's cleaning of the bench. As I wrapped some snap off parts of the knife, and an old razor blade to toss in the trash it occurred to me that I needed a sharps container. So I made a very non osha approved container.

I also stated to SWMBO that one night this week I was going to rebel against everything and work on my plane! And then I got the email about the new Zero, and I Love war birds! That increased the desire to sling hot glue and stab foam board!

I will post Mini Corsair 150 content later this week, I promise!

 

[Stress Test]

And my workspace is clean for the next twelve minutes!

Nothing to see here, move along, move along....

Its all about how you frame the shot, my bench isn't really clean, it just misplaced clutter.

This is my second build with hinges. This time I will document what I found useful and how I do it. Maybe someone will try it or improve on it or show me a better way.

To keep the shape i will need to remove a thin sliver from the hinge area, the mini Scout didn't wrap around the edges so it didn't matter. I also mark the width of the hinges. I mark the depth on the knife to slit the foam.

It looks funny because a sliver of foam escaped. Anyway I use a steel straight edge ruler to cut these.

Then I use a 3/32 piece of plywood as a guide to slit the foam. Multiple passes work better and angling the knife. The ply wood holds the knife parallel to the desk top and elevator. All the hinges wind up aligned in a single plane.

 

[Stress Test]

DO NOT DO THIS. If you slip you may run out of curse words to express your displeasure.

Ok, so the next thing I found out is the hinges need more room than the knife blade leaves. I have a thick saw blade laying aroung and I use it and some plywood to form pockets. I don't pull the teeth into the foam, I use the back of the blade. The teeth leave it jagged, trust me.

The end result is a pocket for glue and hinge, it takes very little glue. Speaking of glue I used wood glue this time as the hot glue set way too fast. I did one side then let it dry overnight.

Then I test fit the second piece before gluing it the next day.

The gaps are easy to line up and let dry. the large gap will be partially covered with a piece of paper, both top and bottom, to improve the airflow.

While not as fast as the FT 45 degree cut and hot glue hinge I think this will hold up.

(Lawyer stuff / fine print / excuse clause) BUT I HAVEN'T TRIED IT YET! So it may fail spectacularly!

 

[Stress Test]

Final thoughts for the night.

The Zero really caught my attention. If this (Mini Corsair 150) works out maybe I should build a Mini Zero 150 and then turn them over to 2 good pilots and they could take turns for the Warbird 150 Challenge at Flite Fest next year!

Yes I know, there isn't any such challenge, yet.