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A KK Senator Cookup (Read 105259 times)
Reply #372 - Apr 12th, 2016 at 3:43pm

Colonel Manfred von Holstein   Offline
Senior Member
Indianapolis, IN

Posts: 283
****
 
Between my schedule and the weather I'm still waiting on an opportunity to test this model out. Had to wait for the snow to melt to mow the grass last weekend...Stupid groundhog. In the meantime I've keep myself busy building a storage and transport box. It's made of 1/2 Gatorfoam board and tape. Inside I built 1/4" balsa keepers to keep everything from rattling around and I can pin the surfaces down to maintain their shapes. Still need to do something to hold the prop though. The box is pretty sturdy considering and maybe the insulating value of foam might give a little margin of error sitting in the back of the car.

Also, my lovely wife surprised me with a used Sidewinder w/counter for my birthday. I'd like to build a music wire torque meter to try out with it. I've found this online resource http://www.modelflight.com/torque.html that show the how-to and the math to calculate wire sizes and lengths, but I'm uncertain what torque range I'll need to shoot for. Any suggestions on what a fully wound 30g motor does in inch/ounces? (Seems like it should be oz/in, but whatever.) Or what size wire and length would be appropriate?
 

3 rules of Free Flight: Keep it light, don't build heavy, and it shouldn't weigh much.
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Reply #371 - Mar 23rd, 2016 at 5:44am

staubkorb   Offline
Senior Member
Stick & Tissue
Germany

Posts: 1328
****
 
Trailing edge shaping (basically what I used for my SENATOR):
Two lengths of steel wire - 0.047 for the TE and .125 for the LE
Wood strip for the part
SHARP knife
Sanding block with various grades of paper - starting with 60 or 80 grit

Sandwich the wood strip stock between the two wires and use knife to carve the strip til the blade is running along both wires.  A couple of passes with the coarse grit sandpaper to take out any high spots, followed by finer grads to smooth out the rough scratches (wood strip is STILL sandwiched between the wires!).  DO NOT USE TOO MUCH PRESSURE WHILE SANDING (new paper, please!) OR YOU WILL END UP WITH A NICE CURVED, TAPERED PIECE!

Remove from wire "bracket" and lightly sand (top and bottom) with 280 or 320 grit (black "wet or dry") paper to take off any fuzz.

FINI Wink
 

WWWoFF
Wonderful Wacky World of Free Flight
(with a bit of rc thrown in for giggles)

Comparing Spammers to a pile of organic waste is an insult to the organic waste!
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Reply #370 - Mar 22nd, 2016 at 12:16pm

applehoney   Offline
Full Member
Ajax, Ontario

Posts: 164
***
 
> some form of jig to get the taper on the TE of the wings? I almost bought the tapered pieces for our Wakefields.

Most preshaped trailing edges are not tapered to a near knife edge so I long ago figured that if they have to be recarved then I might as well choose my own timber grades and do the entire job myself.  I seem to recall that most commercial TE's were either hard and heavy or soft and useless.

No jigs here.  A piece of rectangular stock of the right size and length coupled with a new blade on the hobby knife and I carve the whole thing very finely to a triangular section. 

I do the sanding when wing/stab structure is complete and ready for same, using a block.  The trailing edges need little more than a 'clean up' and all sanding on same is done cross grain.    Sanding along the grain can introduce warps.
 
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Reply #369 - Mar 22nd, 2016 at 12:00pm

Colonel Manfred von Holstein   Offline
Senior Member
Indianapolis, IN

Posts: 283
****
 
Gunny, I sanded the profile before building so I wouldn't have to fuss with protecting the ribs later. My "jig" was a scrap board with a strip of 1/8" glued 3/8" from an edge. The TE sat in that rabbit and I used a sanding block to knock it back corner to corner. 

Pete's drill conversion thread was the impetus for me trying to make my own. When I got to the Craigslist drill (no listing picture) this puny little bugger is what I found. It's got a nice chuck that holds small numbered bits really well so it'll go in my tool box.  I'll keep looking for one more suitable as a winder.

I found the thin wall tubing in 36" lengths at the local Ace Hardware. I read that the clear (uplift) tubes can be found at aquarium stores, but the nearest one is on the opposite side of town so I'm trying this. The figure 8 hooks are made from .062" music wire on a simple jig I made. I read a suggestion that a double loop on the small side helps prevent the ring from climbing the prop hook, so I may try that and larger diameter big loops too.

Not sure I need to though. I fully lubed the motor and put about 80 braiding turns on each half of the motor. It didn't shorten the motor much but it runs pretty smoothly now with no bunching. I think winding technique has a lot to do with it too. The wicked in dope patch has flattened out even more in the last couple of days.

I took the recommendation to keep the tail end light to heart. Trouble is the front end is a little heavy. With no ballast it balances at 2 3/4" (about 1/4" behind the third spar, or 60%.) To get to 70% (3 3/16" or 7/16 behind the third spar) I need to add 3g ballast on the tail. So much for a lightweight model...It's already 74g, which is plan weight. Harumph! The plan CG is directly on the third spar, so I'll try to trim it as-is for now.

Now to just wait for some decent weather...
 

3 rules of Free Flight: Keep it light, don't build heavy, and it shouldn't weigh much.
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Reply #368 - Mar 21st, 2016 at 10:03am

NcGunny   Offline
Senior Member
GO PANTHERS!
NY

Posts: 762
****
 
Quick question Colonel. Did you make up some form of jig to get the taper on the TE of the wings? I almost bought the tapered pieces for our Wakefields but decided against it. I didnt fathom how big and how much sanding would be needed.
 
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Reply #367 - Mar 20th, 2016 at 8:55pm

cdwebb   Offline
Senior Member
I Love YaBB 2.5 AE!
Arkansas

Posts: 264
****
 
Here we go. Pete's take on a hand drill to winder conversion...

http://www.stickandtissue.com/cgi-bin/yabb2/YaBB.pl?num=1374366893

 
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Reply #366 - Mar 19th, 2016 at 1:39pm

cdwebb   Offline
Senior Member
I Love YaBB 2.5 AE!
Arkansas

Posts: 264
****
 
That's an idea worth looking into. I can say without doubt that I have junk aluminum lawn chairs.  Diameter may not work for smaller planes, but 30" on up should work just fine.
 
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Reply #365 - Mar 19th, 2016 at 12:54pm

NcGunny   Offline
Senior Member
GO PANTHERS!
NY

Posts: 762
****
 
CD..I know a local guy that makes blast tubes out of old lawn chair legs..those old aluminum types that always had the webbing rip..lol
 
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Reply #364 - Mar 19th, 2016 at 5:56am

cdwebb   Offline
Senior Member
I Love YaBB 2.5 AE!
Arkansas

Posts: 264
****
 
Nice job on the blast tube, Colonel. Where were you able to source 5/8" thin wall? My local Ace Hardware carries K&B, just not sure he has anything that large.  I bought the blast tube assortment from George at Shorty's, but the one you made definitely looks like it will be taking no c*#p from any rubber band! 

I have some of those little wire figure 8's, but I don't use them on anything a big as a Senator. A medium size Crocket hook maybe, depending on the number of rubber loops, maybe even a large. I don't have any of the "T" hooks, but I've wondered if they would be a handy little thing to have around. 

I can't remember where I saw it, but Pete gave a good description (or explanatory pictures) somewhere of how he converted a hand drill to a winder. I have a nice, well made, older hand drill , but have yet to do the conversion properly. The possibility of the chuck releasing everything is still there. I may have saved that stuff somewhere. I'll look.

In the meantime, knowing you, you'll figure it out. Thinking things out has never been one of your shortcomings. Wink
 
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Reply #363 - Mar 18th, 2016 at 10:19pm

Colonel Manfred von Holstein   Offline
Senior Member
Indianapolis, IN

Posts: 283
****
 
I lubed up the motor really well and tested the prop. It's not bunching up now, but it's got more vibration than I'd like. The prop is very well balanced at this point. I think the issue is my hook and ring. The diamond shaped hook worked well on the Moth, but it used a rubber O ring to connect it. The point of the diamond runs true when spun by the way. I tried the figure 8 on the right first but it kinda climbed the hook at the beginning of the run and banged around the inside nose sheeting (no damage). I then made another 8 but with the loop backwards. This ran better but still with the vibration.

I don't have any crocket hooks, I don't even know which size would be appropriate, and I'd rather not place an order for something so small. I've read good things about a Tim Grey ring (or a "double ring thing" as I've seen it called) which is similar to the figure 8 hook. It looks like those run on a round prop hook, many times they're not even round but a very large radius crescent shape. I guess this large radius makes it easier for the ring to self center.  I don't think there's a question in there, just more rambling while I try to find what works for me.

I got a blast tube made. It protrudes past the fuselage by 3/8" and is flared and smoothed. I drilled a hole in it at 6 o'clock to tie a string onto to pull it out if necessary. I figure the string is less likely to get tangled in the motor at the bottom and it helps to clock the rear when inserting it. The rear notch is a snug fit on the motor peg and will actually self support if turned nose down, so making it a quarter turn affair isn't necessary. The butt of an Xacto file wooden handle was used to flare the tube.

Going to check out a hand drill from Craigslist tomorrow to see if I can make a winder from it.
 

3 rules of Free Flight: Keep it light, don't build heavy, and it shouldn't weigh much.
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Reply #362 - Mar 17th, 2016 at 10:49pm

Colonel Manfred von Holstein   Offline
Senior Member
Indianapolis, IN

Posts: 283
****
 
It did rain a few days last week and it's Sig dope. I don't think my brake grease lube migrated anywhere either. I left it alone for a couple of days to see if it would tighten back up but it didn't. So I used steam to try to shrink it again. Not only did that not work, but it also wrinkled up the yellow tissue behind the cabin. So I left that overnight and both remained loose the next day. I think what might have happened was the orange is either more porous than the rest and needed more sealing, or I my dope brush was getting drier towards the front when I doped the fuselage. I then wet the loose tissue with thinner and when it dried all of it drew up tight again. I added another coat of dope in case the orange wasn't completely sealed before. There's definitely been a learning curve with domestic tissue.

Now that's looking better I tried a no tissue method of patching that I read about. I washed the tear down with a coat of thin dope and covered it with saran warp. The idea is the capillary action of the dope sucks the torn fibers back together and up against the saran wrap. It worked surprisingly well. It leaves a shiny spot in the finish but it drew the tears up tighter and mostly flattened it out. I'll wait to do a full patch repair until after I get some test glides and flights in. Might as well do them all at once and try Pete's trick when I do.

I need to figure out why it knotted up and banged a hole in the tissue in the first place though. It might have been as simple as there wasn't enough motor lube. In other words, trying to keep the tissue stain free might have led to it getting damaged worse. I bought a piece of K&S 5/8" .016" wall aluminum tubing to make a blast tube. I notched the end for the motor peg and rounded the ends to smooth things up. There's not much material in the tube to hook the slots because of the larger motor peg size. It just barely fits between the motor peg sheets and plywood reinforcements in the fuselage. I hope the 9/16" ID is large enough for the motor as it's being wound. How far should the blast tube come out of the nose? Short as possible where you can still grab it out? Would it be a good idea to make a nose plate with a hole to support and center the tube, or even just wrapping the tube with open cell foam so it's not banging around in the fuse? Should my long winding hook for inside the tube be the same gauge wire as the prop shaft or larger?

Pete, I remember you saying you used a smaller motor. The original plan says use 6 strands of 1/4x24", which would be very similar in size to your 25g motor. What's the thought process with using a smaller motor? Less likely to bunch up at less than 1.5 time peg to hook? More docile power burst?
 

3 rules of Free Flight: Keep it light, don't build heavy, and it shouldn't weigh much.
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Reply #361 - Mar 15th, 2016 at 4:59am

staubkorb   Offline
Senior Member
Stick & Tissue
Germany

Posts: 1328
****
 
Want to make the edges of a patch nearly invisible?

A patch or panel that is scissor/knife cut will have a "hard" edge that will always be visible.  A simple light swipe or two with a small sanding block along the perimeter of the patch lightly frays the edge (done at an angle with the edge of the tissue along the edge of some sort of backing - foam board/workbench).  When applied, shrunk and finished, the frayed edge blends in almost invisibly.  About the only clue that a patch is present will be the darkened "doubling" of the tissue.
 

WWWoFF
Wonderful Wacky World of Free Flight
(with a bit of rc thrown in for giggles)

Comparing Spammers to a pile of organic waste is an insult to the organic waste!
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Reply #360 - Mar 14th, 2016 at 8:21pm

terryman   Offline
Senior Member
I Love YaBB 2.5 AE!
Los Gatos, CA

Posts: 865
****
 
Colonel Manfred von Holstein wrote on Mar 14th, 2016 at 1:38pm:
... There's a smaller tear on the right side too. Also, in the last two days the orange tissue on the fuselage has started to wrinkled up. It was drum tight for about a week previous. The yellow and red are still tight though. Don't know what's causing this but maybe the EBM orange is a bad batch or somehow different. I'm going on record in saying that I'll never use domestic tissue again.  I suppose it's just penny wise and pound foolish to use an inferior product. Very frustrated right now.

Noob question: How do you patch tissue?

Regarding wrinkles - Has the relative humidity gone up since you applied/finished the tissue? The higher the humidity the greater the wrinkles.  The wrinkles will go away when the humidity goes back down.  I don't recall what finish you are using, suppose there could be something permanent going on if it is a non-traditional material that stretches from use, humidity, temperature, etc. but does not return to it's original dimensions when atmospheric conditions do.

I have some domestic tissue models that wrinkle a lot with high humidity, others that don't.  Haven't decided if its the tissue, the humidity when the covering was applied or the amount of dope used in the finish.

Patches -
1) Cut out the damaged tissue to the nearest frame
2) Cut a new piece a little larger than the cut-out, in your case I would make it larger on all sides by the frame member widths.  e.g if they are 1/8" make the patch 1/8" larger on each side. 
3) Dope, glue, or paste the new piece on
4) Shrink the patch
5) Apply finish

Depending, the seam can become almost invisible.  I have done this many times using dope.

Terry
 
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Reply #359 - Mar 14th, 2016 at 7:47pm

Sky9pilot   Offline
Administrator
Stick & Tissue
Kelso, WA 98626 USA

Posts: 10919
*****
 
Your wrinkling could be from excess rubber lube getting on the inside of the tissue.  Just a thought.
Sky9pilot
 

If God is your Co-pilot...switch seats...
Your attitude will determine your altitude!- John Maxwell
And ye shall know the truth, and the truth shall set you free. Jn 8:32
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Reply #358 - Mar 14th, 2016 at 1:38pm

Colonel Manfred von Holstein   Offline
Senior Member
Indianapolis, IN

Posts: 283
****
 
The back layer of the nose block is ply already, the screw hole was drilled undersized, then the screw installed and removed, then the threaded hole hardened with CA. I adjusted the stop screw out about two turns and the motor settled in evenly when the prop stopped. Unfortunately, the next time I tried it the motor bunched up in the rear and blew a hole in the fuselage tissue. There's a smaller tear on the right side too. Also, in the last two days the orange tissue on the fuselage has started to wrinkled up. It was drum tight for about a week previous. The yellow and red are still tight though. Don't know what's causing this but maybe the EBM orange is a bad batch or somehow different. I'm going on record in saying that I'll never use domestic tissue again.  I suppose it's just penny wise and pound foolish to use an inferior product. Very frustrated right now.

Noob question: How do you patch tissue?
 

3 rules of Free Flight: Keep it light, don't build heavy, and it shouldn't weigh much.
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