Midwest Lil Snip build

Nice!! I’ll be curious to know how the diamond airfoil works…. I’ve seen them on old plans but never live action…. Certainly would make building efficient…. I have a twin pack of Combat Kittens but no immediate plans for them….Post progress please…. Best

Robert

Diamond airfoils are pretty poor for control line flying. It goes like stink in level flight but the speed just sheds off in the maneuvers. Offer the wing a lot of power to combat the speed bleed off and it does ok. Other designs are light years ahead. While speed isn't the object of combat it helps. The Riley Wooten Demon is a diamond airfoil. I built one I fly at vintage combat and have had some gentleman's matches using it.

         Here's a short video of my son flying it. You can hear the engine unload in level flight and the rpm's come up but in the maneuvers it's pretty steady. Power isn't a real problem here. Fox .36 MK IV on 10% nitro. This engine becomes a monster on 40%.  
          https://www.youtube.com/watch?v=nEO0xmmce4w

Cool video of your boy flying! I don't think I'll be doing that with mine. I'll probably be happy with a few loops and some wingovers and some inverted flight.

Ya know what I am thinking. It's not to late. I could just make a template for a different airfoil (non diamond) and just cut over the ribs. I haven't punched them out yet. And they are pretty typical of the Die Cutting from back then, still in place pretty good. I think I could maybe put a spot of glue on the stamping lines and set a template over each one and draw a line to the template and cut them out. I could just wing it with a French curve (which would be plenty good I'm sure). Or I could get fancy and pick an air foil from the pages and pages of them in my Model Aircraft Aerodynamics book.

It's too bad I don't still have a DOS computer and Dot Matrix printer. I still have the program Foiled Again but it won't run on Windows.

Thanks for explaining the diamond airfoil performance …..Was curious…… And a video as well…. Yes sir that big block is putting out a lot of thrust!!! Thanks for sharing

FlipStart wrote:It's too bad I don't still have a DOS computer and Dot Matrix printer. I still have the program Foiled Again but it won't run on Windows.

Check the site Airfoil Tools. There is a huge database plus 4 and 5 digit generators for NACA foils.  Once you've decided what you want, you can either save it as a PDF or print it on a laser printer.

My best guess is a 17% symmetrical airfoil.  I can't speak to the appropriate thickness or particular shape, but Ken Cook has much more experience in tweaking the shape WRT leading edge, max thickness and at what percentage of the chord.

The Lil Snip is a neat plane, it certainly has a place. Build it as the plans show and it flies fine. So many things were tried over the years to improve performance in combat. The diamond airfoil in my opinion while it was mentioned improves speed of build, it didn't help overall performance. Don't let my post stray one from building it. I just built one I had in a kit from 35 years ago. I haven't flown it yet. What I believe set the Lil Snip aside from others was it's wingspan. Keep in mind that 1/2A combat didn't have the popularity that .35 sized planes had. The Lil Satan for instance, having a reed engine, too thin of a wing and narrow span didn't offer the same results as the Lil Snip or even the Combat Kitten. I raised the concern of the drag on the wing because it will fly better if you offer it more power.

Just subscribing here.  As a kid as mentioned before, I had a TD in a George combat plane which is a copy of the Snip with tail booms.  It had a lot of travel on the one piece elevator and slowed down a lot on the turns.  I liked that, as I could keep up with it and practise squares and stunts.  Later in the year, I gave it less throw with a new horn and it did not slow down at all in the turns, and I could barely control it because of the high speed all the time, and sold it to a friend who promptly crashed it into toothpicks.  Just saying that if it slows down, it is not a bad thing.  Maybe even in combat if you have more control?   Also less throw can speed up the plane in the turns In any case, the main benefit of the diamond airfoil is the quick assembly.  The straight taper on the back slope from the spar is the most important detail for building ease.  I think the straight area on the leading edge to the spar could be why the speed gets scrubbed of in turns.  If making new ribs, a curve up to the spar after the 45 degree square leading edge is all I would do if the speed thing was a consideration.  (it is not for me)

OK guys, Thanks for all the good information and the tip on the Airfoil program. Actually I don't have any printer at the moment as my bread box HP desk jet died a couple months back and I have been lazy in replacing it.

Ken's latest thoughts brought me back down to the realization that I might as well just build the plane stock. I'm only building a combat wing because I happened to have it in my stash of kits from a long time ago and only want to fly it to bring back memories of flying 1/2 A COX engine planes as a kid with my dad. The chances of me ever flying it in actual competition would be slim to none.
I would prefer a profile full fuselage plane much more than a wing and I will probably get one after I do the Snip.

I can go faster on the build to as I'm not cutting out new airfoil shapes and stuff.

I half to iron the kinks out of the plane though so it will lay flat. I'm thinking I don't really need to build it on the plane though.

Great idea!!!! When you get to the bellcrank, I believe Midwest recommends a wood screw to attach to the platform. I highly suggest a machine screw, preferably a 2-56 allen socket head. In addition, when you place the horn wire into the bellcrank, I would also suggest using the inner most hole to limit and slow the throw. Midwest also pre punched knockouts in the outboard wing inner ribs. Use caution here as the rib is very fragile. The knockouts are for a bladder tube to run bladder pressure. It sounds like yours will be radial Cox powered therefore no need for a bladder.  Smearing glue over the knockout would be suggested. Then sand the backside of the entire sheet which will assist releasing the rib from the sheet.

Hey FlipStart… Plus one more on great idea!!…. I bet you can capitalize on the traits of the wing…. Plus it will build and get you in the air quicker…. Watching this one

Thanks for all the tips on the build. I don't see a bellcrank included in the kit. I'm pretty sure I have some but there probably in my storage unit, it's just down the street a ways. I may have a handle for 1/2 A but not sure. There is a nice plastic tool box with a handle that I have all my alcohol plane stuff in over in the storage unit, and I have some 1/2 A size fuel tanks in with the .049's in cheese drawer box. I don't think I have a triangle shaped tank though and I'm thinking that is what I will need to steer the fuel to the pickup in all flight modes.

Ken, I will take your advise on the 2-56 machine screw and I'll use a blind nut and possibly Locktite, or just some glue on the threads. I see what you mean about the bladder tube hole, I'll glue the plug in tight unless there is some other reason to remove it.
I'll take a fresh #11 blade and cut the die cut areas al the way through so the ribs come out easily.

I have a somewhat large red control handle but as I remember it has fairly heavy braded wires coming out and I'm worried that maybe a 1/2 A plane won't pull strong enough to straighten out the cables.

I forgot to ask, I was thinking of adding maybe 1/2 an inch to the 2 booms to maybe help slow down it responsiveness a little for these old reflexes of mine. Does that sound like it would work?

I can't remember, What line and how long do you guys fly 1/2 A on? is it 35ft. of Dacron or something like that. I'll for sure half to get some line and maybe make or buy a handle.

I use 42' lines .008" on the TDs. A reedy I go 30 to 35'. I would not really use the dacron. A lot of guys swear by the new braided fishing line now. Not the monofiliment. You may want to check other threads for details on what to use and the # test.

This build will be interesting to watch. I didn't build my Lil Snip. I found it hanging from the ceiling in a hobby shop that was going out of business.

As I found it.



Thread about it here:
https://www.coxengineforum.com/t13449-unidentified-1-2a-combat-plane

Another Snip thread here:
https://www.coxengineforum.com/t13451-snip-1-2a-combat-plan

And another one here:
https://www.coxengineforum.com/t14779-lil-snip-build

I personally wouldn't lengthen the booms. That will induce more tail heaviness leading to the plane porpoising up and down if you can even fly it all. You want your line spacing on your handle to be no greater than 2 1/2" apart. Any further will lead to a over controlled plane. When you install your engine make one of the bolts longer and after the engine is cinched down, bolt some weight on the nose. I see your engine crutch is already built for a beam mounted engine. If a TD is in the picture, you may want to use that bladder tube. The problem with the bladder tube provided is that it;s too skinny. Any modern bladder material won't be able to expand within it.

In this area we could get a 1/16" I.D. thin wall surgical tubing that went to about the diameter of a thumb. Worked OK for bladders in a 1/2A. You may want to look in a well stocked drug store before you decide on a tank. I had a hard tank in my old George/Snip TD wing that worked well though.

@aspeed: thanks for the information on the guy wire length and maybe what to use. I'm really hate the thought of using a bladder.
I saw the tank someone made in another thread and think I will go that rout.

@TLAnderson: Thanks for the picture of that Lil Snip. If mine comes out half as nice looking I'll be happy.

@Ken Cook: thanks for all the great information Ken. I found the handle I knew I had. WOW! it's got 5" of line spacing so that is way too much I would think. I may half to just make a small handle from wood.

I got the ribs all cut and punched out. That went good, Midwest's die's are sharp I guess. Pretty good wood in the kit, the spars are fairly straight, one has a bit of a bend at one end but not bad.

It sounds like to me that you have the 5" EZ-JUST red handle which is too large for even flying .35 size planes. They also made the Hot-Rock which was just under 4" which suits most sport flyers well. Depending on engine choice, tanks could prove a bit of a problem. If you can get the tank directly behind the engine which I don't think is possible, your forced to go outboard. This can be hit or miss with a Cox TD. If a tank is the option, finding a skinny but longer tank is most helpful. Reason being is that you want the pickup of the tank as close to the centerline of engine venturi as possible. Even offering some engine offset makes the centerline of venturi closer.

@Ken: Yes it's the EZ-JUST handle.

It sounds like the little .049 just doesn't have enough draw from the small amount of air passing through it's venturi to draw the fuel against much force from the inertia while in flight. Does crank case pressure being fed to the tank help much? I think I have the .051 drilled for crank case pressure hook-up. I was running it in a little Quickie 200 with that cylindrical tank I made.

I went back to my storage unit Saturday and took some stuff back there and got other stuff out. I got the COX engine boxes back out and the small engine prop box out. I brought 2 ACRON bins back too; there might be a bell crank or 2 in one of the drawers.

There wasn't much for U-Control on my black box, just a fuel bulb, my Kraft glow plug guy, some guy wire and the hand control.
I went over to Viper Hobbies but they had almost nothing for U-Control or COX.

HaHa!.. I think I found a CL club here in the valley. The Central Arizona CL Club. It looks like they have 2 fields they fly at and neither the one I saw some CL flyers at years ago, but pretty close to the same area so I bet it's the same club. Their fields are on either side of the 10 but in Avondale which is a goodly distance from me but doable.
And their OK with guests that have AMA cards and I do.

That's cool maybe you can hook up with some to bee friends to do some fling , It's always more fun with someone to help or helping out another and the talk is Good !

I'm thinking I'll drive out to the 2 fields this weekend and see if anyone is flying. Maybe I can get acquainted with some flyers and also find out where they are getting things like fuel, guy wire and stuff like that. Maybe someone has an extra handle they would like to sell.