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Video & Flight report - Shoestring Stunter (Maiden V.2.0)

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Video & Flight report - Shoestring Stunter (Maiden V.2.0)

Post  RknRusty on Sun Mar 17, 2013 7:30 pm

I woke up excited today, my first flight of a large plane and the maiden voyage of my Shoestring Stunter. Over the last few days, I had e-mailed a couple of interested friends that said they wanted to be there. So I had a big breakfast for a big day flying and headed out to the club field about 11:00.

No one was there yet which suited me, I could relax and make new bladders for the two Baby Flite Streaks. Still nobody there and too windy to fly the babies. By 2:00 I had the lines hooked up and everything sitting on the circle ready to fuel and go, and I was contemplating making a pull line stooge and going at it alone, when a truck and trailer pulled in. It was a couple of guys I haven't met yet. We chatted and I told them what I was up to, and needed launch assistance, but no apparent interest.

After they flew for about a half hour, one of them finally decided to launch for me. So off we went to the CL circle. I wanted to just fly on a sip of fuel to see if it was trimmed and airworthy, so I put an ounce in it and cranked up. After warming up I had the needle where I wanted it, got up to pick up the lines and it shut off. It ran a lot longer than that in the shop Friday. So I put in some more fuel and got out there and waved it off.

I gave it too much up elevator and it jumped straight into the air without rolling(point deduction) and around it went for the first lap. The engine sounded good. I had put a 9x5 prop on it, an old style wide Master Airscrew, and it flew flat and stable completely unaffected by a pretty stiff breeze. Y'all had told me it would pull pretty hard, but I had no idea it would pull like a solid clay red brick, damn, can't fingertip this plane like I do the little ones.

So after two laps I flipped it over to fly inverted and was surprised at how quickly it snapped over and leveled off. I'm used to having to coax a plane back flat after flipping it, but this was as smooth as ice. It sputtered for a moment during the turn, but kept running fine. I pulled an outside loop with no problem except it sputtered again. Went back to normal flight and did a loop on the next two laps, both times sputtering , once causing loss of altitude and a brush with death, but it recovered and flew on. About that time, maybe a minute into the flight it died right as it was coming into the hard crosswind and I had to trot backwards to bring it in. It touched down with a tailwind rolling briefly and flipped over it's nose. I cursed my poor landing, but there was no one there to hear me. My assistant was half way back to the RC field. It didn't scratch any of the pretty off though.

I don't know if the needle wasn't set quite right, but the engine shouldn't have sputtered on every loop. I was able to pull 1/2oz out of it that hadn't been used. I put the syringe on the other tube and drew only air. Given the opportunity I could have tried different needle settings, and tried the other tube out of the tank, but it wasn't to be. No one else ever showed up. Strange, Sundays have been busy every time I've ever been there. It was 80, sunny and fine.

I got tired of hanging around and went to pack, and noticed the wind had died a little. So I got the babies out and flew both of them for about five flights. In fact I flew the crap out of them... in sort of an aggressive irritated way. Busted two props, but no wood. I headed home, not nearly as happy as I had hoped to be. I was tired, but not from what I had intended to accomplish.

No videos, in fact the camera stayed in the car. But at home I took some post flight photos. Y'all haven't seen it since it was completely finished, so here:

Check out my tank strap, made from a soup can(and I definitely need to shorten that needle):









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Re: Video & Flight report - Shoestring Stunter (Maiden V.2.0)

Post  Ken Cook on Sun Mar 17, 2013 7:47 pm

Rusty, congrats on a job well done. The plane looks terrific and will certainly be enjoyable in flights to come. Ken
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Re: Video & Flight report - Shoestring Stunter (Maiden V.2.0)

Post  Kim on Sun Mar 17, 2013 8:10 pm

Great Rusty!

I really like having my own launching stooge, as most times with a new model or such, I'd just as soon NOT have helpers or spectators !
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Re: Video & Flight report - Shoestring Stunter (Maiden V.2.0)

Post  RknRusty on Sun Mar 17, 2013 8:16 pm

Yes, y'all are both right. I just need time to work out the kinks and i was really disappointed that didn't happen today. My next opportunity will be in two weeks, or whatever week the weather permits after that.

I posted the same story at RCG since Tigreflyer was interested in the plane.

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Re: Video & Flight report - Shoestring Stunter (Maiden V.2.0)

Post  Mudhen on Sun Mar 17, 2013 8:17 pm

That looks awesome, Rusty. You're quite the builder, or in this case master restorer.
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Re: Video & Flight report - Shoestring Stunter (Maiden V.2.0)

Post  Cribbs74 on Sun Mar 17, 2013 8:38 pm

Lol, I wasn't kidding about the pull! Even though it didn't run as well as you would have liked it was still a succesful maiden. It could have been worse!

I am sure you will get it right. You definitely ragged on it harder than I did mine. I was satisfied with just a loop or two Very Happy

Where is the tank pickup located in relation to the NV?

Congrats Rusty!!!! The Shoestring turned out great!

Ron
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Re: Video & Flight report - Shoestring Stunter (Maiden V.2.0)

Post  RknRusty on Sun Mar 17, 2013 8:51 pm

Thanks, Mud and Ron.

I can only infer the pickup's actual location, but since I can draw all the fuel out with the corner of the wedge at the lowest point, and none is still sloshing in the tank, I'd say it's right where it's supposed to be; in the back outside corner. There was no performance difference in engine RPM upside down or right side up, only in the turns.

The picture makes it look like the wedge is a little lower than the NV, but the outside of the tank is about even with the NV, within an 8th of an inch


Last edited by RknRusty on Sun Mar 17, 2013 8:56 pm; edited 1 time in total

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Re: Video & Flight report - Shoestring Stunter (Maiden V.2.0)

Post  Cribbs74 on Sun Mar 17, 2013 8:54 pm

Guess I could have looked at the picture closer. I am not an expert by any stretch and maybe Ken can weigh in, but that tank seems a touch high and may be causing your hiccup problems.

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Re: Video & Flight report - Shoestring Stunter (Maiden V.2.0)

Post  RknRusty on Sun Mar 17, 2013 8:59 pm

I was editing my post when you posted that. So you think maybe I need to raise mine a tad? I need to open it up and take a look.





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Re: Video & Flight report - Shoestring Stunter (Maiden V.2.0)

Post  Cribbs74 on Sun Mar 17, 2013 9:13 pm

If I understood Ken correctly, he told me to pkace the pickup 1/4" higher than the NV. Of course he was talking about a Fox .35 so we may be talking apples and oranges here.

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Re: Video & Flight report - Shoestring Stunter (Maiden V.2.0)

Post  Ken Cook on Sun Mar 17, 2013 9:24 pm

Rusty, seeing you had no noticeable rpm differences right side up vs. inverted I would say your tank height is just fine. It could be something as simple as a plug change if you have a hiccup like your explaining. Was the engine too rich on launch? Prior to launch, pick the nose of the plane up and point it vertical and the engine should break lean returning to rich in level position. I'm not there to witness just suggesting.Generally, many engines when mounted sidewinder like on a profile, will have fuel forced into the bypass causing a stutter. This is extremely recognizable in the Fox due to the overly large bypass. Seeing this is a modern .25 I would say this is less noticeable but I would also try a hotter plug like a Thunderbolt r/c long, Sig R/C long, Enya #3 or OS A3. What fuel where you running? Some engines just don't like certain fuels especially fuel with too much oil content. Is the spray bar properly aligned in the crankcase? Did you try and open the uniflow vent to the atmosphere and run it? It appears to me that your on standard vent. If you still have a bit of fuel left in the tank, you can shim the rear of your tank slightly outboard to assist in the fuel feed. This wouldn't cause the hiccup you suggested however. If your plane is yawed out and this is hard to see if flying solo your pickup may not be tangent to the circle which would cause the excess fuel in the tank and typically a unclean cutoff towards the end of the flight. That choppy run at the end would certainly be recognizable. I would exhaust all options before getting into the tank. I personally am not a fan of the fuel line feeding up and then down and then up again. I personally would replumb the tank with the pickup exiting the bottom as in Ron's configuration. That however is my personal preference and I'm not suggesting for you to do that. I would certainly try the other options available such as uniflow and muffler pressure and see if the same results persist. Ken


Last edited by Ken Cook on Sun Mar 17, 2013 9:43 pm; edited 1 time in total
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Re: Video & Flight report - Shoestring Stunter (Maiden V.2.0)

Post  RknRusty on Sun Mar 17, 2013 9:41 pm

I was running Sig 10% nitro with 20% oil, half castor, half synthetic. I'm using an OS #8 plug. I can get another type of plug if different tank configurations don't help. If I'd had more than one flight, I would have moved the cap to the overflow with the uniflow open. I also had the muffler in the box in case I wanted to try pressure. The reason I didn't start out that way is because it's already nose heavy, but I just had no opportunity to experiment. I'll take a look at the spraybar alignment. I did run it leaner than wet 2 stroke, but not much, just an off-peak 2 stroke. I had a bit of trouble with the needle. Recall I said it shut off and I added more fuel and re-cranked... well on that second crank it wanted the needle significantly turned in to get the same sound I had the first time, the off peak 2 stroke. Than made no sense to me.

By the way I was using a 9x5 old style wide GF Master Airscrew. Y'all have told me that engine will run well with 9x4 to 10x4.

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Re: Video & Flight report - Shoestring Stunter (Maiden V.2.0)

Post  Ken Cook on Sun Mar 17, 2013 9:45 pm

Well, it sounds to me like your fuel is correct and is your plug. The #8 is the A3, OS switched numbers but the plug is the same. I would try uniflow for certain. Your prop choice isn't off base and if anything it would've made it fly fast. If it was loading the engine, sagging would've resulted or certainly a noticeable load on the engine. Seeing you had no muffler, the engine was running quite happy with no restriction. It just may take some little bit of fiddling, but you'll certainly get it. Also, just to let you know if you do decide to use muffler pressure, that yellow cap isn't suitable enough as is to run muffler pressure. I place an additional piece of fuel tubing jammed over it. If it pops off during the run, it's off to the races and fuel will be forced out of your tank and all over. Ken
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Re: Video & Flight report - Shoestring Stunter (Maiden V.2.0)

Post  RknRusty on Sun Mar 17, 2013 9:57 pm

I know I will. I just didn't get the itch scratched today. But it still looks pretty hanging in the shop, so I can go visit it from time to time.

One thing that surprised me is that though I didn't do a proper takeoff, it just turned on its tail and shot up into the air with no straining to get going. It went from zero to flying full speed as soon as I waved to my launch man. So I don't think weight is a problem at all. Its AUW is 31oz. More than Goldberg says to build, but considering the repair, I guess I did okay and my engine obviously has the guts for the job.

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Re: Video & Flight report - Shoestring Stunter (Maiden V.2.0)

Post  Mark Boesen on Sun Mar 17, 2013 10:27 pm

CONGRATS RUSTY!!!!

I've been looking forward to seeing finished pics and flight report!

(That's the way it goes sometimes when you're all pumped up for something and it really doesn't go like you thought it would...)

Like Ken sez, its hard to say when you're not there...but i'll go ahead and rattle off some thoughts:
Was engine lean and loops leaned it too much?
What about uniflow, did you cap overflow or uniflow vent?

The tank does look low, but not critical. I think i'd raise tank, bolt muffler on and run uniflow w/ pressure. I think plug is new and shouldn't need to be a hot one to run in 2-2-2 mode.

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Re: Video & Flight report - Shoestring Stunter (Maiden V.2.0)

Post  Mark Boesen on Sun Mar 17, 2013 10:32 pm

opps, posted before i read, i think you nailed it, open uniflow and plug overflow.

also, get stopwatch and time level lap times as well as total run times, unless you flying the pattern, most crashes are fuel depletion based!

i think a 10x4 might be good, but get the tank set up first.
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Re: Video & Flight report - Shoestring Stunter (Maiden V.2.0)

Post  RknRusty on Sun Mar 17, 2013 11:07 pm

Won't it fly slower with the 10x4?
next time i get out, I'll be able to do plenty of experimentation. You might be right, it could have been leaning out in the loops. I should have set it richer like I was told to do.

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Re: Video & Flight report - Shoestring Stunter (Maiden V.2.0)

Post  Mark Boesen on Sun Mar 17, 2013 11:16 pm

i don't know. i'd rather be on the lean side as oppose to no speed and slack lines, yep, the 10x4 will go slow, but should pull better, thats why i was wondering what kind of lap time you were getting? stay with the 9x5 till you get tank figured out then maybe try 10x4?
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Re: Video & Flight report - Shoestring Stunter (Maiden V.2.0)

Post  gcb on Wed Mar 20, 2013 2:32 am

RknRusty wrote:Won't it fly slower with the 10x4?
next time i get out, I'll be able to do plenty of experimentation. You might be right, it could have been leaning out in the loops. I should have set it richer like I was told to do.

Thunder Tigers are not noted for their fuel draw. i don't have the pro but I have the GP .25 which has plain bearings. Re - the needle, an old trick is to file a groove around it to establish a place where it will break outside the venturi. Mine has a sprinkler venturi similar to a Cox. I'm guessing yours does too.
I would suggest trying a 9x4 or 10x4 and run it just below peak RPM . This will increase venturi velocity which should increase fuel draw.
Don't remember if your engine is new but if it is expect it to gain performance and fuel economy for the first 10 or so flights as parts seat. That means it may richen during a run.
Don't try to run this engine like a Fox .35, it's not timed to do so. Run it just a little rich and adjust airplane speed with prop pitch. As someone already mentioned, a good starting point with the needle is to point the plane up and set it on the rich side of peak. That should ensure that it does not go too lean when it unloads in the air.
Of course these are only suggestions and opinions...use what works for your setup.
Good luck.

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Re: Video & Flight report - Shoestring Stunter (Maiden V.2.0)

Post  RknRusty on Wed Mar 20, 2013 10:59 am

My Thunder Tiger actually has a Super Tigre NVA on it. It was broken in by its previous owner, that would be Mark Boesen, and I don't think it has much run time on it. Mark is the one who changed the NVA, so I don't know how that affects what you're telling me about tuning it. Thanks for the input, though. I'll get it figured out if I can just get a few flights in.

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Re: Video & Flight report - Shoestring Stunter (Maiden V.2.0)

Post  Mark Boesen on Wed Mar 20, 2013 11:33 am

it would be the same, George is referring to the type of venturi the engine has. A lot of people hold plane vertical and set needle, others will pinch fuel line...six of one or half a dozen of another.

I think there's a old saying or rule of thumb for setting up prop: "Pitch for speed and diameter for RPM"

Sounds like the 9x5 worked pretty good, maybe a little lean but had good speed? I could see a old wood Topflite 'paddle blade' might just be the ticket, actual lap times once needle is set will help determine if a 10x4 might be a option.
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Re: Video & Flight report - Shoestring Stunter (Maiden V.2.0)

Post  RknRusty on Wed Mar 20, 2013 12:13 pm

Considering I'm used to 1/2As rocketing around, in the short flight I had it didn't leave me with the slightest impression of having been slow. I think I had it too lean. I was feeling a bit rushed and didn't even do a good pinch test for richness as I had done while testing it back at the shop. I think it was all my fault that it sputtered, probably leaning out in the loops, but it burned a circle pretty fast even with only a 5 pitch. It was a wide blade MA 9x5 that you gave me with the engine.

I bought a couple of the new slimmer MA props and I bet they won't have as much thrust. I will try all sorts of different props, including the 10x4 whenever I get to fly it again.

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Re: Video & Flight report - Shoestring Stunter (Maiden V.2.0)

Post  Mark Boesen on Wed Mar 20, 2013 12:43 pm

I guess i consider that a 'standard' width prop, a wide blade would be a Zinger 'W' or a old Topfilte

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Re: Video & Flight report - Shoestring Stunter (Maiden V.2.0)

Post  Dizzyman2011 on Sat Mar 23, 2013 10:54 am

Hey rusty congrats on making a FIne looking aircraft there loving the colours and finish real slick that is big thumbs up
Remember if modelling was easy then everyone would do it
It might get the grey matter working but once it's sorted out ou will know that what you have done has improved it no end
And after all we are all trying for that sweet spot on a nice warm day when everything goes right and the laps get imprinted in your brain
Or maybe that's just me strive for the best I say
Time to not go and have a fag now I think
Dizz lol!
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Re: Video & Flight report - Shoestring Stunter (Maiden V.2.0)

Post  RknRusty on Fri Apr 05, 2013 8:25 pm

Got stooge, will fly. Sunday is supposed to be 74F with 4mph winds. I wrote "FLY" on the calandar this past Monday. I'll possibly be alone as there's some sort of fly-in at a sod farm in a nearby town. There is another event pretty soon, the Joe Nall Fly-in, about 100 miles from me at Triple Tree Aerodrome.

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Re: Video & Flight report - Shoestring Stunter (Maiden V.2.0)

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