The Refried Bean Build-It flies

Hey Rusty,

A little late, but my two cents worth...a couple things to consider, thickness of balsa and plastic covered or painted?

Monokote type hinges: looks good if same color covering, pre-make both sides before cutting, not real strong for ukies, prefered for small, plastic covered R/C

Sewn: strongest, ugliest, unless looking for OT look, need to seal to prevent oil seepage, especially with plastic covering.

Hinges, pined type: great for larger models, used wood glue to install.

Plastic, thin non-pinned: strong, easy to use, CA to hold, trim down for smaller models, works on thinner balsa as only Xacto needed to groove. trim hinge to a point to ease installation.

Thanks. Since this is intended to be a 100% high stress plane, I'll leave the Monokote idea alone. I saw some kind of small glue-on hinges at the LHS recently. I'll look at that again. And I'm going to look at the fabric selection at some craft shops and see what might work.

Since that's on hold until next week(another wedding weekend coming up), I worked on getting the last of the paint off, sanding and shaping. I also added small corner gussets inside the wings. Since I'm going to need a little weight behind the CG point, I might as well make it functional, and this wing seemed too weak in its original form for its new job.

You know what I hate about football season... Weddings!

Hiya Rusty this is I'm fairly sure the largest Extreme Flight running on the fibre 'slot in and cyano' hinges.
As you can see by what the rudder is doing throughout the rolling harriers they certainly
get a workout. Take a look around 1.28 he's pulling a knife edge spin which is one of the
highest stress manoeuvres on any airframe and the hinges are soaking it up.

John Goddard wrote:Hiya Rusty this is I'm fairly sure the largest Extreme Flight running on the fibre 'slot in and cyano' hinges.
As you can see by what the rudder is doing throughout the rolling harriers they certainly
get a workout. Take a look around 1.28 he's pulling a knife edge spin which is one of the
highest stress manoeuvres on any airframe and the hinges are soaking it up.

Man, that dude can fly! Yeah, he's putting it to the test alright. I can't slot the 1/16" balsa for the CA hinges but, maybe I'll re-make it out of 1/8". I read that you can slot it just fine. Like I said, I'm already light in the tail anyway, might as well make it functional. I detest sticking dead lead slugs on a plane. I might run out to the hobby shop today. Right now I'm taking a detour. I'm headed out to the shop to set the Norvel up with its fine thread NVA and find the needle setting. It'll be set up to power the Bean when she's ready to fly.

I am really looking forward to seeing the video of the Norvel pulling the little Bean around. It should have more than enough power to please.

fit90 wrote:I am really looking forward to seeing the video of the Norvel pulling the little Bean around. It should have more than enough power to please.

Yeah no kidding. Going to be a real hot rod! The video should be entertaining. Go Rusty!

cribbs74 wrote:

fit90 wrote:I am really looking forward to seeing the video of the Norvel pulling the little Bean around. It should have more than enough power to please.

Yeah no kidding. Going to be a real hot rod! The video should be entertaining. Go Rusty!

Damn right, Go Rusty! Hurry! To the hardware store and get a P-trap for the friggin' bathroom sink!!! Grrrr... there is NO, I repeat NO amount of money you could pay me to be a plumber!

Oops, spontaneous rant. Now back to the regularly scheduled airplane.

Oh, the joys of home ownership! One airconditioner repair, one well pump/switch repair and one sprinkler system repair in the last seven days. I'm there with you. Kinda makes you enjoy the time you get to spend on the fun stuff a little more,

I can tell you first hand, hardly anyone uses CA hinges on control line planes due to them being too stiff. This is the case even with .40 size airplanes. Using them on a 1/2A plane would not be a good idea. They have a memory and always want to place the elevator back to neutral and they just don't suffice well for control line flying. The CA wicks all the way through the hinge causing them to get even stiffer and eventually ends up cracking. They also require a slot deeper and wider than a barrel hinge. In the event you hit the ground, I've seen CA hinges just rip out of the thin wood we use for control surfaces leaving a almost unrepairable surface. This also happens with barrel hinges sometimes. I've seen this many of times for those who have used them on ARF models that provided them. Mark raised the concern of fuel impregnation. After I sew the hinges I use a toothpick and typically use a dot of Ambroid (white glue would work equally as well) on each thread top and bottom. This also holds the stitching and seals it. If done correctly, it looks better than cloth over and under style in my opinion. I have several models built that way stitched in different fashions and I could provide pics. The other aspect is that 1/2A control line planes generally don't have as long as a life span as larger models as they just get run to the mill. What I mean by this is that it's probably better to use a type of hinge style that improves flying characteristics vs. cosmetics. Ken

Good points, Ken. I have used fine fiberglass tape since my first balsa plane and never ever had a problem. I think in the absence of glass I can find some strong non-stretch cloth that will make a good over and under hinge. The fabric in my last two Brodak kits seems good, but I don't know what it is. Maybe cotton.

in case I decide to sew, I want to ask you about the basswood strip you pre-bore the holes in. Do you use one on each side of the elev and stab, or is one on the bottom of each surface enough? Would Dacron be a good thread? I have heard about carpet thread, but I think that's Dacron too. Also, what's your way of keeping paint off of the joints?

Okay, got the Norvel set up with the fine thread NVA, running and ready for the Refried Bean. I put a 6x3 MA prop on it, which is really big, but I did it for several reasons. One reason is, when I first maiden this plane I don't want it to be over powered so I put the prop on that I was thinking of maidening with. Second is it's the prop NV Engines recommends for this engine... why, I don't know, but they do. Third, I thought maybe it would be easier to crank while I hunted for the needle setting.

I had to crank for a while before I landed in the right spot, but I found it at about 4-1/2 turns. It spun up and was really neurotic until it warmed up and I got it to lean out at about 17.9K RPMs. I tinkered for about 3 tanks of fuel, trying to pinpoint where it runs rich and lean. It's a lot more sensitive than a Tee Dee. The slightest bit too much off-peak and it cuts off. I may have been getting some air past the venturi gasket, so I'm going to permatex it before I run it again. Or I may have had too much compression for the 6" prop. I also tried it with the muffler on it and it lowered the RPMs by 1500. I'm going to switch to a 5-1/2" prop next time. It will probably run better like that. If so, that might be the one that gets the maiden flight. This engine still has some loosening up to do before it's really broken in. By the last run, the needle was at 5 turns.

Every time I cranked it, it had to warm up before I could quit pinching the line and let her rip. The Tee Dees just hop up and go, so I'm just learning the quirks of a new engine. It did get more cooperative on each run, but it still doesn't like to run at anything off-peak... like rich for a launch. Maybe the smaller prop will help that. I think I have two head shims in it right now, maybe it likes less compression for a bladder feed. Some of you engine experts might be able to help me on that.

Your scaring me Rusty....

Have you tried messing with fuel line supply line diameters? It's another variable.

I suppose a smaller ID feed line might make it a little less sensitive, or maybe just change the peak needle position. A lower pressure bladder would too, but I'm betting as the engine breaks in it'll probably get easier to needle. Maybe a higher % nitro might help. I'll see how the smaller prop and compression affect it too. I'm pretty sure it'll work like it is, I just have to seal the venturi and get used to it.

Rusty, here is a few pics of different sewn hings styles I used. To avoid confusion, I will just start with the colors. The yellow stab and elevator are completely bass. This is due to the abuse mouse racing takes. This type of wood requires predrilling and I predrill the balsa as well but it's not really necessary. The orange stab is a single elevator on a .40 size speed plane. The reason for the different threads was due to the black thread coming loose and needed to be redone. The plane does close to 135 mph and I was getting flutter which frayed the threads. The thread is heavy duty sewing thread and not standard thread. The newer threads is Kevlar thread. They're single stitched looping through each hole about 3 times. The red stab (blurry pic) is a Ultrakote stab and elevator. This is 3/16" material and sewn right through the elevator. The triangulated small stab is plywood. The red stab with the white stripes is all balsa no basswood and sewn with unwaxed dental floss then painted. I don't feel my hinges look unappealing in any way. Ken

Ken, what type of knot do you tie off your thread with?

I myself tie the knot on the bottom as the finishing knot is a bit unsightly. I tie a clinch knot and then I secure with a drop of white glue. I'm not a big fan of CA. I think it's great stuff, but I find when gluing something like this, it wants to wick into the hinge area. It can be a little more time consuming. I can tell you though, it's quite free. Ken

They look quite good Ken, I have shyed away from them and used the nylon hinges for mine. After your explanation the other day I can see why it may be a bad thing with them returning to neutral.

Ron

IIRC, about a year ago we had a discussion of stiched hinges and Kim suggested some excellent ideas and posted several pictures of how he does them. (This was before Ken came on board CECF)

It is in the "search" file. Look under "stiched hinges. I just checked and they are still there.

Dave, what do those abbreviations stand for? I believe I've seen you mention them before. Ken

If I Remember Correctly.

Thanks for asking that Ken. I had no idea either

All I can say that some of you of the younger set may not realize that the memory is the SECOND thing to go; don't ask what's the FIRST.

IIRC is "computereze" from a bygone era like ROFLMAO or DIIK.

I like the way those stitches look, especially the last two pictures. I may go that way after all. That task will be done sometime this week. I'm almost ready to make this thing start looking like an airplane.

And in response to one of Ron's posts in his Jumpin Bean thread about protecting the bellcrank from repeated stooge pulls, here's how I braced my bellcrank mount with a bamboo skewer, Ron, keep in mind my replacement ribs are strong and hard balsa. The originals were very soft and lightweight, so you'll have to decide if this is something you can do with your kit. Another option would be to run two braces out at an angle and let the LE and TE spars(terminology?) absorb your stooge pulling action, rather than the next rib.
I thought you used a tail release pin for a stooge. Are you thinking of making a wing-pull type?


Notice the pad the brace butts against on the outer rib. Also notice, for future repairs, how I mounted my replacement ribs to stubs of the old ribs.


The crank pivots on a 2-56 hex nut with a blind nut on the bottom. I made sure epoxy got on the threads before I tightened the screw. Any time you want to unscrew an epoxy fixed screw, heat the head with the tip of a soldering iron and it will unscrew freely. I do this on motor mounts too.