MJD

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Back to this project again. Got distracted for a while..

- Added flush cooling vents to fuselage either side. Used sanding drum to cut tunnels, lined with 1/64" ply, sealed up.
- Got muffler outlet cut in cowl without butchering it too badly. One ugly coat of red epoxy on cowl, need to wet sand it and do it again.
- Jett 4oz bubble free tank.. I am contemplating putting it on the CG with a Perry pump/regulator. The aircraft is so light, don't care about the extra weight all that much.
- Aileron and elevator (fuse rear) servos mounted - HS-85HB's. Will use HS-85MG for rudder/nose gear. Some micro for throttle. 430 mH 2S LiPo + Novak regulator Rx battery.




If I did this to another one (doubtful) I would make a different horizontal stab, too much elevator relative to fixed area for my taste.

It would look cool with a header and tuned pipe instead of the muffler. Hmm.

Gotta put the RCAF emblems on too, can't forget.

combatpigg

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It looks real good MJD. Working the muffler in like that with a full cowl can be like building a ship in a bottle.

BTW..does any one build "ships in a bottle" any more?
To speed up an epoxy cure I use a 60W light bulb inside a make shift "oven" built with scraps of styrofoam. I just try to arrange them so that the fire department doesn't have to come out at 2 AM for a marshmellow roast. I've got an inside / outside type thermometer to keep track of the cure. Once fully cured the epoxy paint melts like butter with 320 grit or finer. Right now I've got a 20 foot long x 14 foot wide "oven" curing an epoxy primered car project. It is below freezing outside and 85 degrees in the oven right now with just basic lighting and 2 propane heaters set on low. I'm using foil faced 1 inch foam for the ceiling of this "big oven" and it has turned this time of year into a great time for painting because there are no bugs or much else floating around on a cold day in November.

MJD

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My workshop is so cluttered it is liking working on the ship while inside the bottle. This airframe amazes me, it is so light and stiff and strong in all the right places. The wing in itself is really well done. Light, light, light, all the torsional strength you could ask for. This wing would be equally at home on the shoulder of a Stik, in the middle of the fuselage of a Hots or Pizazz, you name it. All of a similar breed. The ailerons are the only part that concern me, I will have to manage top speed I think. The servos are nicely placed about 40% out or so, but they're just plain big and are built up. But I think if I stick to an 8-4 prop and not try to fly it like a missile it should be fine. I think it will be nicely powered with this .15.

I don't have a working scale right now, but should grab a fish scale or something. It feels like it will float.

These days I cure epoxy on the cat tower beside the wood stove, or in the wake of the box fan that blows over the stove. Years ago I made a curing oven from an old fridge cabinet, and a small ceramic heater. Worked perfectly. The insulation and plastic is fine at any temperature you would normally use. That got left behind on a move, should make another one..

MJD

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I wonder how stupid it would be to put a header and pipe on the Magnum .15? The idea of a pint-size piped sport club field terror has a certain appeal. Would look cute, and cool.

combatpigg

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OS clone .15s are pretty common, so if any pipe system was to drop in my lap for the right price.......

Otherwise it's a pretty high price to pay for such a small amount of aluminum. I will say that the makers of these parts are absolute wizards at cranking out this functional jewelry. I'd rather put the same money towards getting something hotter than a piped Magnum if your only option is buying a new system from MACs.

MJD

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Well that's just it, I already have 2 .15 size pipes on hand, so all I need is a header - this is why it is tempting. I originally was going to mount the Conquest or OPS .15's, the Conquest rear exhaust is a pain on this model, and the OPS is an 8 oz .15 (sweet engine but.. oink!)

Thing is for this type of aircraft the throttle behaviour of a can muffler is likely preferable. But the bling factor of the pipe.. oh, decisions decisions.. ;-)

Andrew

Hey!! Bling trumps reason every time!!!

combatpigg

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This was my situation, I had the pipe but no header. I called MACs and they didn't have a header in stock and the price quoted made me dizzy. They offered to sell me a length of prebent tubing. I made my own flange and that was quite a bit of work to drill a series of holes with a mill bit, a cheap cross slide vise and drill press. The trick is to tighten the tension screws on the vise until it is practically too tight to move. The flange is about 3/8" thick and it's tapped for 6-32 screws. The tubing is flattened to match up with the hole in the flange and then aluminum soldered. Aluminum solder WILL hold up to the heat of a .OS.15....but not much more.
Oh..the tubing measures .640" on the outside and it passes into the hole in the flange instead of butting up to the flange.
The soldering process was easier than I figured with I think it was MAPP gas or else propane. It's the fitting of the parts that take all day.

BTW..a FOX.36 Combat Special weighs about 8 ozs, with ABC and ball bearings thrown in....So the OPS .15 must have a really thick brass liner, carb and crankshaft to be that heavy

MJD

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The OPS .15 is a fine engine indeed but yeah, it is built like a brick - the power of a .25, and the weight too (and more?). The case looks identical to their .15 car engines, in fact the literature lists aero and car versions. Lots of liner. The small crankshaft passage and side exhaust are impediments, but mechanically I think the engine could spin a 6-4 at 30+ all day without whimpering. I'll put it in a sport quickie type of design, or another small Demon.

BTW I just closed a deal for a laser cutter, and will start making the delta kits myself.. finally. And other stuff. Once I get through the learning curve.. and get it past my wife.

combatpigg

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That will be a nice tool to have to generate hobby income with. Would it also cut leather..?
How about nylon sheet..? I like having nylon laying around, it's as handy as having aluminum but it is a pain to cut with a band saw. I hate the trash that it creates whereas a hot knife type operation would just need ventilation to handle the mess

MJD

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I'm buying it from a guy that figured he would generate income with it. Apparently that didn't work out.

My goal is to offset it with some products, but it is also just something I have fantasized about owning for a few years, and bingo the right deal came up. I'd prefer a 24x48 platen, but you need to add digits to the end of the price tag for that kind of size.

Because laser cut kits generally take advantage of the ability to have interlocking tabs and slots and other features that are a PITA to do by hand, I find the process of designing something then waiting days for the parts to get cut, then.. oh, wait, I have a better idea, do it again.. wait.. etc. - all very frustrating and unrewarding. However, drawing something, cutting the parts, testing the idea, etc "like now" all with tools at the fingertips is a whole different story.

And it will cut SD kits:



I'm dying to get back at the Mock Nun. And .15-.25 Demon. And a host of 1/2A and other designs I have lying around.

AndyW

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I'd buy three kits of this if they were lazer cut.

MJD

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Funny you should mention that. I have a strong urge to do some sport aero stuff for .10-.15, and also specifically for the NV .074. Just for fun. And.. one of my all time favorite sport aircraft ever was my Midwest Sweet 'n' Low Stik. I used a slighty cranky but respectably strong Picco .40, 10-6 APC I am sure, and I recall this was my first wing mounted twin aileron servo model ever, no more torque rods. I recall being astounded at the difference in control feel. It was a sweet flying aircraft, honest, predictable, forgiving, but very sporty as all good Stiks are. I remember a club fun fly - I took off, did three rolls immediately after rotation, three loops, killed the engine top of the last loop and horsed it in for a landing fast as I could, which turned out to do the trick. It was the only event I ever entered in my life, I think I won a set of trike gear snow skis. Point being though, a guy took off right after I landed and I guess he figured if that ugly, boxy ol' Stik could do that, so could his new painted and pinstriped .20 Sportster. Got messed up inverted in the first low roll and re-kitted it hard. Ouch.

I have a cute little 1/2A bipe drawn up too. And.. oh the bucket list goes on.

MJD

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Oh and by the way, that is a sweet looking model! Nice job.

AndyW

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Thanks MJD, and of course the real cedit goes to Mr. Phil Kraft of Kraft radio fame. As the story goes, he needed a simple, basic airplane to test gear as it was developed. I'd bet that his design has been built, copied, re-sized, ARFed more than any other. I've done a half dozen myself over 40 years including one for a gasser. Very much wanted to do one for a throttled TD .010 just to say I did them all but my throttle just robbed too much off the top end.

Now we have electrics that dominate the uber small field and that just may be what I do this winter. NEVER thought I'd say that but my nephew has "turned" me, at least a little bit.

And speaking of .074, one thing I don't recall ever seeing is a Bipe Stik. All them ribs,,,, and that's where lazer cutting comes in.

MJD

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What are the general dimensions of your Stik?

Andrew

BTW, I've always liked your plane --- the lines, colors and layout just all comes together for a really nice looking model. I took Patrick Ulmer's DNU, flipped the fuselage over, changed the tailfeather shape and made it a low wing --- it looks very much like yours.

This is not a Bipe-Stik, but it does come very close to being Stik like.

AndyW

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The wing span is 34" and the chord is 6.75" excluding the ailerons. On the lekkie side, I think I have the perfect power train for a 19" span version using traditional building methods with a weight, less than 2 ounces, or 50 grams. Battery would be a 180, 2S and I'd make it to also take my TD .010 just to see how it behaves with both modes of power. I suspect that the .010 would be faster on the flat outs, but the lekkie would have the advantage in the verticals.

I WAS going to try and Lekkie up the current Stik, (in need of severe repair) but with the new shipping restrictions on large and expensive, (and delicate) LiPos, I'll stick with the really small stuff for now.

If I were to build another Stik from scratch, I think I'd up it to 36", for a bit more wing area with little increase in weight. That's because the original (shoulder wing) was built over 15 years ago for the VA .049, MK1 which was very light but not as powerful as a current, Norvel .06. Not that power is a bad thing, but when you can accelerate going up, from a hover, well, that's overkill.

There are lots of .40 and .60 sized originals that could make very good, 1/2A models even when sticking to exact dimensions, as in shrinking the plans exactly like the originals. My Tsunami does what it's daddy did on a piped .40 and now that I have the .074 doing really well on a CS pipe,,, This is a go fast ship with LARGE maneouvers.

The other big ship I'd like to do someday, is the Super Kaos, I just came across the plans the other day. What I like about it is the thick airfoil and the slower flight envelope it had in the day. In the day when tons of power and speed, was NOT the norm. That big Kaos did well on a Webra .60 Blackhead which had very good power, in the day when Schneurle porting, again, wasn't the norm. Oh lord, that goes back some 40 years or more.

AndyW

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Andrew,

Wonderful little design. I especially like the fin/rudder outline. Keeps the oldtime feel with a modern touch. I may steal it if I do a Bipe Stik. Thanks. What amazes me about the Stik is that it needs no down or sidethrust. How that works is a puzzle to me, the original was built to plan but I shimmed the usual down and side thrust into it and found that I was taking out shims, one at a time till there WERE none. I had attributed that to the low stab aspect but the low wing version has the stab at the top. Could it be the unique airfoil along with JUST the exact moment arm and stab and fin area?

I have a foam Citabria bought some 30 years ago at the Air Museum in Ottawa. It was rubber powered and flew very squirrely. Just when you thought you had the right amount of right and left thrust in, you had too much,,, no stability in this bird at all, despite the quite adequate dihedral.

Well, the past month, I insatalled a lekkie powertrain, thinking, with control, now we will find out wattsa matta wit dis ting.

What happened was that ANY rudder input would send it off into a spiral dive. The solution, as I learned, (and forgot) was more fin area, which I accomplished without destroying the outline and look. Good grief, no wonder it wasn't stable. Still needs lots of down and right thrust but we can live with that if it does the job. Originally it was on 1S with a small motor but it wouldn't loop from level flight so it now has a 2S system. This is the powertrain I have in mind for the lekkie Low Stik. The Citabria, now stands at 78 grams, or 3 ounces. I think a Stik could be built to 50 g or 2 ounces.

Geez, I can't believe I'm talking lekkies.

MJD

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Could be spiral instability, it has a lot of vertical fin area.

My go-to 1/2A wing dimensions are 30" x 6" to 6.5" total chord Hershey bar with 1" tips .for 32" total span.

I have already had a couple of Mach One inspired prototypes cut. I built the fuselage but was PO'ed at the lightweight wood the cutter used (another strong reason I want this under my control) and although I like the structure, there are a couple of little changes I want to make. I went a little hog-wild on the first wing design, I will simplify it a bit. And, that first draft used a fat NACA airfoil to duplicate the ACE foam wings. I'll make some changes and get back to that at some point. I never built the wing because same deal, he used punky wood for the ribs, TE etc. This was a cash deal, cut me two prototypes, so I didn't make a big deal about it, but it is an example of how it can take the patience of Job to get through the R&D stage when you live in a rural area and rely on outside services. That ain't how I'm wired.

I think a pattern-inspired design dedicated to the .074 would have to be good fun. And a ripping aerobatic bipe. And..

MJD

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Bigger eh? I have tendency to try to go silly small these days, likely a symptom of being excited about small radio gear. One of the 32"x6" winged models I built years ago was an exercise in lightness, with 1/32" ribs, LE sheeting, capstrips, etc, a 1/16" balsa box fuse with minimal reinforcement, contest grade 3/32 tail surfaces, and some synthetic tissue covering that was the rage at the time, not micafilm though. Stik type proportions but the nose tapered down to just fit a Black Widow firewall. Never did weigh it, come to think of it, but I figure in the 10-11oz bracket. It was the hottest flying 1/2A I ever built, on a 5-3 and a particularly good running BW, it moved out nicely, lots of vertical, rolled like a top, would turn in a blink, and after cutout glided like a feather. I used to glide it up and catch it on my left hand. I recall thermalling it too. The point is that was a more sane sized 1/2A effort, not so far removed from your Stik, and it went like a bat and had a great glide ratio. I should resurrect it some day, needs minor repair due to hangar rash and abuse. I remember starting out with a Dragonfly thinking the clunk tank was the ticket, but it was a POS, never got steady runs.

I had actually forgotten about .074's for a while, not realizing they were still readily available until recently. I have never owned a Norvel .074 but have wanted a couple for ages, on my Christmas list this year.

Ideally I get the Mock Nun worked out and built, as a vehicle for the VA MKII R/C. I have a set of micro retracts too.. hmm.

AndyW

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Well, in fact, the original fin area is in yellow and insufficient area led to yaw instability. In white is what I added and that actually cured the spiral instability.

That reminds me of a big gasser someone built, a high wing, cabin job, forget the name, that had a rather smallish, total fin area to begin with. Full size pilots would comment that you had to be on the rudder pedals constantly to fly the thing and it would very easily go into a spin compared to a Piper Cub.


The designer of the gasser model compounded the problem by making the fin area even smaller than scale. The test flight was a disaster. When aileron was given, the plane WENT THE OPPOSITE WAY. No, the throws were not reversed but the plane behaved that way.


The totally inadequate fin area could not compensate for something called adverse yaw. That happens because the down aileron creates drag and yaw in the opposite direction. Some aileron designs such as used on the Spitfire would create more drag with the up aileron than the down aileron. But the fin is there to get control of yaw and that gasser sure didn't have enough.

AndyW

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For me, for the Norvel .06's, a slightly larger model at the same weight would allow for some really great, low and slow aerobatics. I do have a great little Fora .020, done up with a throttle that Japanman rigged up for me. But it has a brass cylinder and fins and a strong crankcase and believe it or not, A VA MK1 .049 is the same weight. That one has no liner, the nickle plating is deposited directly on to the case bore.

Well, that would be another, interesting project. An identical, 32" Low Stik with either engine. And as pointed out, with the really small radio gear and a LiPo for a battery,,,

The original Stik used Cannon "micro" servos and "micro" receiver. Alongside today's 2.4 gear, the Cannon stuff looks huge.

But too many Stiks can get boring.

I can take the Super Kaos plans to the local printer and get them downsized and build them to exact scale in any size I want. Something not possible not that long ago.

Ya gotta just love the new technology. Someday, we may be able to bring a CAD design to the local, 3D print shop and have them do up a prototype, aluminum crankase in an hour or less at a very reasonable price.

MJD

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Reading too fast, so I was. The fin I see is the one that works.

MJD

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Look at the Tiger Moth - they have nearly 100% differential aileron, an interesting chain and bellcrank arrangement. And with lower surface only, the roll rate doesn't exactly snap your neck. Sailplanes also good examples of adverse yaw - with short tail moments and longggg wings you learn very quickly that the pedals are more than footrests.