Author Topic: Shoestring-the full ride (Read 4292 times)

Randy Powell · « **on:** May 15, 2008, 11:00:10 PM »

OK, I've been posting pictures of this thing since I started building it a couple of months ago (well, more like 3 and a half months - I took some time off). So, here is the final product. Just have to wrap the leadouts, but I ran out of steam for that tonight. I'll do it tomorrow and get ready for it's maiden flight this weekend. The weather is even going to cooperate, it seems.

Statistics:

Powered with a PA 40UL "Merlin"

I weighed it tonight. It sat on the scale while I worked up the courage to look: a shade over 48oz before balancing (though the static balance seems pretty close). The fore aft balance came in right on the money, so I think I'm good there. I built the nose a bit beefy, so I was afraid it would be nose heavy. I had hoped for 45, but hey, the original was 59, so I guess I shouldn't complain.

Prop is the one Randy Smith recommended. An 11.25x4 Narrow 3 Blader that is repitched to about 4.4. That will be the starting prop, but have about 10 ready to try. I start with .015 62 foot lines and may go down depending on lap times.

This is the first plane I've built in awhile that actually looks better in person than in the pictures. It has flaws (trust me) many, many of them, but overall, it's not too bad.

Clint Ormosen · « **Reply #1 on:** May 16, 2008, 12:48:55 AM »

Looks great Randy! A classic design with a modern flair to it. Beautiful.

Mark Scarborough · « **Reply #2 on:** May 16, 2008, 08:43:35 AM »

Randy,
really nice,, strikking I would say even,,

Randy Powell · « **Reply #3 on:** May 16, 2008, 10:36:51 AM »

Mark,

Well, it's not as "Ornamental" as yours, but it should be serviceable. I hope to get the maiden flights on it this weekend so I at least have it semi-trimmed for the Regionals. Should be a decent plane overall. And I can get back to finishing the PA plane that's been sitting there for months.

Clint,

Well, it has checkerboard. But not as much as the Chip. Not sure I could stand doing that much the way I did this. Wish you could make it to the Regionals. It will be fun in spite of the forecast. (rain, of course).

Steve Helmick · « **Reply #4 on:** May 16, 2008, 03:31:17 PM »

Looks great, Randy! Tho I'm still wondering about the tiny bit of checkerboard on the left wing. Maybe I'll see it at Tacoma Narrows this weekend....

I left work at noon and went by Mike H.'s, to see the new Shrike, and did just that. It looks pretty good, but still hanging on the paint stand, which makes it hard to picture the whole enchilada. Color combination is interesting. Tho if he'd told me over the phone, I would have been unable to predict how well it actually does work. I didn't see a single ink line, and he's been polishing the auto clear topcoat, so I reckon there won't be any! New tech for Mike are removeable flaps and elevators, and neatly done.

Steve

Randy Powell · « **Reply #5 on:** May 16, 2008, 03:36:12 PM »

Steve,

yea, I plan to head by the Narrows tomorrow to give the new bird a test flight or two. Hope the wind has calmed down by then. Maybe 10 am or so?

Dennis Adamisin · « **Reply #6 on:** May 17, 2008, 06:16:09 PM »

Don't remeber that last time I was so excited waiting for someone ELSE's test flights! The Shoe is fantastic, the power package looks great, heck you even get almost a week to trim & practice, right???

Don't keep us hangin!

Randy Powell · « **Reply #7 on:** May 17, 2008, 10:36:31 PM »

Dennis,

Well, it was a good news, bad news day. The good news is, the plane flies pretty well sans some trimming. The bad news is, there was a hole in the tank (and I checked right before I put the thing together after finishing it). I got raw fuel all over the nose and am now in the process of repainting a bunch of the nose. Sigh... Oh well, it will be fine in the end I guess. But it's pretty disheartening. It looked pretty good before that but I doubt it will ever be the same. I can't believe there was a hole in the tank. I know how it happened, but still, it's one of those stupid things you just don't expect. The paint crinkled all over the nose and I'm trying to patch it up. But it's not easy with dope as a base finish and catalyzed polyurethane as a top coat. I keep having spots where the clear is pulling up. Oh well, it is what it is. Hopefully it won't look too bad in the end. At leas the thing flies pretty well.

RC Storick · « **Reply #8 on:** May 18, 2008, 12:45:09 AM »

Quote from: Randy Powell on May 17, 2008, 10:36:31 PM

Dennis,

Well, it was a good news, bad news day. The good news is, the plane flies pretty well sans some trimming. The bad news is, there was a hole in the tank (and I checked right before I put the thing together after finishing it). I got raw fuel all over the nose and am now in the process of repainting a bunch of the nose. Sigh... Oh well, it will be fine in the end I guess. But it's pretty disheartening. It looked pretty good before that but I doubt it will ever be the same. I can't believe there was a hole in the tank. I know how it happened, but still, it's one of those stupid things you just don't expect. The paint crinkled all over the nose and I'm trying to patch it up. But it's not easy with dope as a base finish and catalyzed polyurethane as a top coat. I keep having spots where the clear is pulling up. Oh well, it is what it is. Hopefully it won't look too bad in the end. At leas the thing flies pretty well.

I had this very same problem with a repair. I used masking tape to pull clear off to a color sepration line. Cut with razor blade at line. Scuff dope and re finish. Then re clear. You can't tell the differance.

Steve Helmick · « **Reply #9 on:** May 18, 2008, 12:47:01 AM »

So, how did the tank get that leak? I'd fire the guy that did the pressure testing, yup!

Steve

Randy Powell · « **Reply #10 on:** May 18, 2008, 09:37:41 AM »

Robert,

Yea, that pretty much it. I just had to get the catalyzed poly sanded back past the repair (not easy with a lot of compound curves). The repaint the repair areas and recoat the nose with clear. Should be fine in the end, just irritating.

Steve,

Well, I think I know what happened. I had to reposition the little hold down tab on the back of the tank. I checked the tank for leaks when I put it in, but must not have used enough pressure to expose the leak. I guess. Sure was leaking freely when I pulled the tank out of the nose, that's certain.

Update

Well, no one will see the Shoestring any time soon. The attempt at repair has only made it worse. I've shot catalyzed polyurethane over dope on probably 15 planes and never an issue. But for whatever reason, this one is a problem. I fixed the paint (looked pretty good too) but when I shot more urethane over the repairs, the entire nose crinkled up along with part of the wing. No idea why. It's never happened before. Not sure I'll even fix it. I'll just throw it in the rack when it dries and when I get over being mad at it, I'll take it down and strip it back to the primer and try again. Maybe.

This is the second Shoestring I've built. The first on suffered from engine problems it's entire short life and it finally ended when the engine (with plenty of fuel left) quite in a Cloverleaf, splatting unceremoniously into the pavement. It was really a good flying plane, but I never really got to see it's potential due to constant engine problems. This one, it seems, is as cursed as the last. At this point I've determined that it's just a design that, for me, is subject problems. If you ever seen the movie, Gone In 60 Seconds, this is my Eleanor. So, baring a miracle, don't expect to see it any time soon.

Sigh...

Mark Scarborough · « **Reply #11 on:** May 18, 2008, 06:47:42 PM »

Not to spoil Randys fun, but I just got off the phone with him. I think its all going to work out in the long run. Sounds like the repair problems arent as severe as initially suspected. We all know how emotions can screw us up right? well sounds like this plane will be a great flier for him and I am looking forward to seeing it in Eugene!

Randy Powell · « **Reply #12 on:** May 18, 2008, 06:57:59 PM »

Mark,

That's what I thought before the last repair. I think I can fix it, but then, I thought I could fix it the first time. Guess we'll see. It's partially repainted and I'm going to have to sand all the clear in the repair area without going through to the paint and make sure it's all flattened out before I try clear again. And I don't know what I'll do about the edges.

Sigh... as we said when we spoke on the phone, most of the time this stuff works out fine. But when it goes south, it goes big.

Randy Powell · « **Reply #13 on:** May 18, 2008, 10:34:54 PM »

Ty,

Actually, after talking to Mark, I feel better. We think we diagnosed what happened and why. I hope to avoid problems this time.

Randy Powell · « **Reply #14 on:** May 19, 2008, 10:51:14 AM »

Yea, I should have been suspicious when the plane went together so easily. This thing was really easy to build for some reason. Even the finish came out pretty well with almost no retouching. I should have known.

I'm starting to think that all planes have to have a certain amount of pain and frustration attached. It builds character.

Shultzie · « **Reply #15 on:** May 19, 2008, 04:02:16 PM »

Quote from: Ty Marcucci on May 18, 2008, 07:04:18 PM

Hmmm. Try a Nobler, and paint it solid blue with dope. Brush it on. Back to basics I say.

NOBLER?..WHAT THE ELL' IS THAT? A DINA-SOUR-SORE?

WHERE IS MY OLD SHOE TO FLOG THE CRAPOLDDO OUT OF U!

Dennis Adamisin · « **Reply #16 on:** May 19, 2008, 04:10:37 PM »

Randy:
Can you back up a little bit. I understand you had a leaky tank and got raw fuel on (in?) the front end. I don't understand: why the crinkly paint? DOpe finishes usually are OK, is the catalsed urethane NOT fuel proof? Is it a case where fuel can sep BETWEEN the dope later and the urethane layer and cause it to all go to blazes?

Sheesz, I might have to coerce you into using E-power

- or monocote!

Randy Powell · « **Reply #17 on:** May 19, 2008, 10:39:20 PM »

Dennis,

Well, normally this wouldn't have cause much of a problem. But I had sanded the clearcoat pretty thin then polished it up. Problem is, when you do that you "break the skin" and it allows the fuel to get in. It's still relatively fuel resistant (probably more than dope), but not as immune as it would be if you didn't sand it. Problem is, I don't have a concrete floored, water film, downdraft paint booth so I inevitably have a bit of dust, bugs, what have you drift into the clearcoat. Consequently, I sand the clear and buff it up. Give a nice, very lacquer-like effect. But it also kills a lot of the fuelproofing.

The reason for the crinkling when I shot on the clear after repairs was determined (after a head session with Mark Scarborough) to be adding reducer to the mix when it was too hot (air temperature-wise). Should have just mixed the paint and hardener and left it at that. Also, I used reducer shot around the edges to help blend it into the original top coat and I probably shot it on a little to think in too hot a temp. As Mark noted to me, the stuff works pretty well 95% of the time. It's the other 5% you have to worry about. A bit of forethought would have avoided a lot of pain.

On the bright side, I got the repairs done and shot the clear on tonight. It's a lot cooler and I mixed the paint up without reducer and shot it the used the pencil point on my airbrush and went around the edges of the repair very carefully with some reducer laid on very lightly. Looks like I might have gotten away with it, though I suppose the proof of that will be when it's sanded out and blended. As I said before, it will never be a concours winner (and that was questionable before the accident), but it sure as heck won't be now. But it should be presentable. Sorta.

EddyR · « **Reply #18 on:** May 25, 2008, 12:21:41 PM »

Randy didn't you have the tank and motor area completely sealed? I put a drain hole in the tank compartment.I have had the same problem over the years and since then have made a way for the fuel to get out with out damage to the plane. A few years ago I had a tank seam leak in a Viking that the tank went into the leading edge with out a sealed compartment and the fuel went right to the wingtip as I flew the plane.By the end of the flight which was rather short the outboard tip was down 6" in level flight. We put a match to it.
Ed

Randy Powell · « **Reply #19 on:** May 26, 2008, 04:14:22 PM »

Ty,

Yea, it's definitely drawn some blood. I did learn at the Regionals that I screwed something up. I build the inboard flap too small. Sigh. I'll put a tab on it and do some field testing then build a new flap. That should take care of the rolling problem it's experiencing. Other than that, just have a slight engine mod and I should be good to go. It's not at all a bad flying plane. Showed some real potential in it's first contest.

Randy Powell · « **Reply #20 on:** May 27, 2008, 08:16:58 AM »

Ty,

Yea, hard to tell what I'll do at this point. I need to calculate how much more I need. I suspect I just mis-cut the thing to begin with. so I will probably just glue on a tab and go fly it, trimming it off in each successive flight until it turns flat. The I can calculate how much to add to the flap and just build another flap. It's not ver hard to do it that way.

Overall, it's a pretty good flying plane. I hadn't thought about the need to put the leadouts back further than I might normally due to the pretty small tail plane. But a bit of adjustment in the leadouts (rearward) and a bit of adjustment to the rudder (straightening it) and the yaw I was getting on hard turns went away. Now, I just have to get rid of the tendancy the thing has to roll at me on hard control. I tried packing in some tip weight, but that really didn't solve it and only created other problems. So that came back out. We'll see. Like any new plane, there's some futzing around until you work out the bugs.

Mark Scarborough · « **Reply #21 on:** May 27, 2008, 08:23:14 AM »

BUT Randy, It is a gorgeous plane and it looks awesome in the air. Well worth futzing about with to get it flying right. Look forward to Puyallup, you are going arent you? Pat wont be so we have to hold up our contingent.

Randy Powell · « **Reply #22 on:** May 27, 2008, 01:17:44 PM »

Mark,

Yes, I'll be there. Hopefully, I'll get plenty of trim flights between now and then and have it flying pretty good.

Randy Powell · « **Reply #23 on:** May 28, 2008, 09:36:16 AM »

Just a note for those that think they might want to build this plane:

1) Make sure you follow the plans and get all the asymetry in (don't ask).
2) Use the Skylark root and tip templates instead of the plan templates. The drafter screwed them up. The original had a FoamFlite Skylark wing.
3) Pay attention to the position of the leadouts. This plane has a rather small tailplane and the leadouts do need to be that far back. If you get them too far forward (about were logic would tend to say they should be), you will see some wicked yaw. Get them back to where they are marked on the plans and you get a very nice, flat turn. Go figure.
4) Have fun - it's a neat plane.

Another note. I used a PA 40 UL Merlin for power. Works pretty well. But I made a mistake. I was getting some charging out of corners, probably due to the tank design. I decided to put a "spigot" in the venturi like I had previously with the regular PA 40. This did fix the problem, but I forgot to punch the venturi out to compensate for the lost choke area due to inserting the spigot. Make a huge different in available power. So I took the venturi back out, calculated the amount of lost choke area and drilled out the venturi to compensate, restoring the lost area then inserted a new spigot. We'll see how it goes when I get out to the field next, but I don't foresee any problems.

Mark Scarborough · « **Reply #24 on:** May 28, 2008, 09:56:42 AM »

Randy
Just wanted to make a public note here of appreciation. Its really educational to hear of your trials , errors and more importantly the solutions. It helps us "wanna-bes" to avoid the same, or more importantly when were trapped in a cycle of errors we can have more info to find our way out.
I really like the shoe,, its a knock out airplane.
Looking forward to seeing you in Puyallup!
gawsh, I dont have any repairs to do, maybe I will start sanding thd 109 now,,

Chris McMillin · « **Reply #25 on:** October 10, 2008, 11:38:00 PM »

Hi Randy,
My buddy James Mills is looking for a source the Shoestring plans and I cannot find it in your thread. Could you give us a heads up on a plan source?
Chris...

Randy Powell · « **Reply #26 on:** October 11, 2008, 03:56:45 PM »

Hi Chris,

My plans are the Flying Models plans. CF 237. With alterations as noted. Bob Hunt is a good source for information about the original. He actually flew it and can tell you what was different from the published version.

Chris McMillin · « **Reply #27 on:** October 13, 2008, 03:00:46 PM »

Thanks Randy,
James already bought my foam Skylark wing cores and is just having difficulty finding a copy of the plans. Thanks for the lead.
Chris...

James Mills · « **Reply #28 on:** October 14, 2008, 07:21:05 PM »

Randy and Chris,

Thanks, I place an order for the plans last night.

James

Randy Powell · « **Reply #29 on:** October 14, 2008, 10:21:56 PM »

James,

Watch out for that triangular stab. It did me in. The Shoe is currently sitting there without a stab (had to cut it out due to some alignment problems I just couldn't trim out). Hopefully, the new PA plane will be done in the next week or so and I can get a new stab cut for the Shoe and get it back into the air. It's a neat plane.

James Mills · « **Reply #30 on:** October 14, 2008, 10:33:29 PM »

Quote from: Randy Powell on October 14, 2008, 10:21:56 PM

James,

Watch out for that triangular stab. It did me in. The Shoe is currently sitting there without a stab (had to cut it out due to some alignment problems I just couldn't trim out). Hopefully, the new PA plane will be done in the next week or so and I can get a new stab cut for the Shoe and get it back into the air. It's a neat plane.

Randy,

I haven't seen the plans yet, so what's the deal with the stab?

James

Randy Powell · « **Reply #31 on:** October 15, 2008, 10:46:39 AM »

James,

It's triangular in shape and very hard to both align and to keep it from warping during the finish process. Mine was straight and aligned when I built it, but sometime during the finish process I got an unrecoverable twist in it. After some attempts at both triming around it and straightening it (none of which did what I had hoped), I cut the thing out and am building another. This one will be more airfoiled and probably built up to maintain the alignment when it's refinished.

Steve Helmick · « **Reply #32 on:** February 01, 2009, 08:26:12 PM »

The Shoestring saga continues. It flew again today at TNA. It looked a lot better to me this time, with a Rabe rudder hooked up and working, and apparently a better prop. Randy had several flights with it, adjusting the new handle, etc., launch RPM and such. Then Peterson flew it, and now Randy has to start trimming in earnest. Pete said it flew like a truck, basically.

This Skylark wing thing is kinda strange. My Skylark was on the line behind Randy's, and I'd swear that the Shoe wing has a bunch more taper, with quite a bit more LE sweep. Schultzie and I were looking at the LG placement on the Shoe, and it was rather forward compared to the Skylark. I was rather amazed at how little taper the Skylark wing has, actually.

Steve

Shultzie · « **Reply #33 on:** February 01, 2009, 10:14:33 PM »

Steve..
Years ago...when I first saw Southwicks beautiful Skylark fly....even today that SKYLARK to me...is still one of the most elegant CLPA model ever designed. Around 1968??? I was given a partly assembled Skylark kit by Tim Dunlop on one of his trip to Seattle. Tim had just mounted a VERY heavy foam wing that he found somewhere (maybe from Leo Mehl?

)
Anyhooo, When Tim put it on the scales...it didn't have flaps, a top block or even wheels or rudder and it weighed somewhere around 54 ounces.
Tim made me an offer I couldn't refuse...( VIRTUALLY FREE!) I had a generous amount of Aerogloss freebee spray cans that I traded for him, plus I had a box full of old alumn. Froom Spinners that I gleaned from the old GreenLake hobby shop in Seattle.
After I finished that Skylark with the foam wing...it weight only around 64 or 65 ounces. The Model was painted BLACK AEROGLOSS..(GADS! NOTHING SMELLS AS SICKO' AND WEIRD AS AEROGLOSS GLOSSY BLACK DOPE...I WONDER WHAT THE

VD~ELL CHEMICAL FORMULA...makes BLACK smell so badly.
I trimmed that model with gold trim and covered it with that beautiful AEROGLOSS transparent CANDY APPLE.
barebottom line:
I flew that model for about a month...AND GAVE IT AWAY! That poor old Merco 35 just wouldn't pull that much weight.

OPPS STEVE AND RANDY...sorry for KIDNAPPING this post...
but STEVE!
When I saw how nicely that great flying lightweight SKYLARK of yours flew today and how nice it looks in the air.!!! I COULDN'T STOP THINKING ABOUT THAT OLD SKYLARK from my demented past.

I would have loved to take up your GENEROUS OFFER to test that Skylark of yours...except that I couldn't feel the fingers of my right paw...from all that cold weather and was more than afraid that I might lose grip on that handle.
That is TOO NICE OF A FLYING SKYLARK to take a chance with...plus YOU FLY THAT SKYLARK so well. I think it must suit your flying style. You look really comfortable with that model and looks like you have it pretty much DIALED IN THE GROOVE.
Hey Steve.
You gotta HEAL BROTHA...that COLD air today must have take a tole on your bummed out ankle!
Hope the MEDS start to kick in soon so you can get back to NORMAL..(what ever that is?

)

Randy Powell · « **Reply #34 on:** February 01, 2009, 10:35:49 PM »

Steve,

The wing was done from Pat Johnston's Skylark layout. I assume it's the same as the original. This was the smaller, original Skylark. Don't know much more. Bob Hunt said that the original had a Skylark foam wing, but he didn't specify which Skylark (there were several). I assume it's the smaller one. The gear is too far forward for my taste, but are right on where the plans locate there. Sigh... sometimes you just have to follow the plans (it is a Classic plane, after all). the rest of it follows the plans. Even the CF gear is an exact replica of the original with fairings. A bit wide for my taste, but again, it follows the plans.

I felt the plane was a bit nose heavy. Pete flew it and said it was a LOT nose heavy.. So, plastic spinner, probably replace the tank with a plastic unit (if I can get it to fit) and perhaps some interior, uh, weight loss work. We'll see. If not enough, I'll add a bit of tail weight (I hate it when that happens). the wiggly rudder needs a bit more work, but it's getting there. I did a bit of steaming of the stab, and it seems to be holding, so hopefully that is done.

Randy Powell · « **Reply #35 on:** February 07, 2009, 10:55:46 PM »

For those of you that heard me say that this was my second Shoestring, here's a picture of the original (my original, anyway). It was actually a better plane. Shame the engine was a dud. This was taken the day it went in. sigh...