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Shoestring flying with a 1/2A prelude-6/2/2013

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Shoestring flying with a 1/2A prelude-6/2/2013

Post  RknRusty on Sun Jun 02, 2013 8:36 pm

Part One-The Streaks
A Looooong day at the field.

My new neighbor Chris and I loaded up the car with planes and set out for the club field today. He's wanted to see the Shoestring fly ever since I put on my first 1/2A exhibition for his family. We got an early start hoping to beat the wind and got out there about 10:30. The club was empty but since I was expecting the usual Sunday crowd, we drove onto the old sloped CL field and unloaded the gear and started setting up. I usually pack the whole shop so anything that might go wrong is covered.

So we picked our launch spot and everything is ready to fly the SS. I opened the tool box. Where are my flying lines.
I said, WHERE ARE MY FLYING LINES!!!? In the shop of course.

Okay, okay. Let's just fly the babies.
So out come the Streaks. I gotta get some Cox contest run time anyway. We'll take a break after that and go get the lines. I wanted Chris to fly, so BFS-II/Norvel went into the stooge, hooked up the 45' lines and fueled it up. I had been having venturi leaks so I did a bang up job of making a new silicon gasket and a tiny gasket to seal the screw hole where it had been spewing fuel lately. Cranked it up and got it needled, and it quit. Now, wtf! The new silicon gasket had popped and jumped out sitting on top of the engine. Well hell, I'm glad we brought a lot of planes. We're getting off to a rocky start.

So out comes our last chance, BFS-I with the Cox Contest .051. As usual it cranked right up and we're off to the races. Cranked, needled, launched. I flew like my day had been going so far, ugly, but didn't land prematurely, so that's good. Been a while since I flew 1/2A on long lines and it showed, but it was a warmup flight. I flew it again and all was back to normal and I was racking up contest time. Very nice flight and my usual nose-over landing. Now Chris assumes the position in center circle with a big slow prop on the Streak. I pointed it slightly up and out, he waved the signal and it went slightly up and straight down for a 2 second flight. Rewind, do it again. I kept getting him to show me full up, neutral and full down, but the same results. So this time I point it up at a 60 degree angle and that's where it went... 60 degrees up and 60 degrees down. He says he never fed it any down but was back peddling and said the lines are slack. I thought maybe something was wrong with the plane, so I flew it again. Really nailed some nice wingovers, lazy 8s lots of insiders and outsiders and some tight overhead loops. We need to get that boy a trainer. He is itching to build a plane, so we're going to pick one out for him. We did video my warmup flight and his sinusoidal halfwave flight, but nothing worth uploading. He'd had enough of trying to fly, so we took a break and drove home to get the steel lines for the Shoestring.

Fast Forward: Went home, got the steel lines and a nice refreshing air conditioned ride in the car. I was refreshed. Chris is 24 and in the Army, so he doesn't need refreshing, but he's fun company, 4 years younger than my son.
I'm sure glad I had a ribeye and scrambled eggs for breakfast.


Part Two-The Shoestring

Now we're in business. I was about to hook up the lines when our club president comes rolling in. "Hey Rusty, if y'all aren't too far along setting up, come on up and fly on the RC field.". He had some friends and his Brother-in law and he wanted them to see a CL exhibition. Awesome! Nice manicured grass field and no friggin' slope to make half the circle 4 feet higher than the other side. He said Wayne is coming. Wayne is his old flying buddy that has flown everything. I'd met him once when we flew together and he flew his big one and I flew my babies. He knows a lot about precision stunters too, which is what I really needed, someone with observations, ideas, and answers. He rolled in about the time Chris and I finished lugging our gear-half the shop, plus the lines-up to the big field. Wayne had a beauty of an OS .46 powered plane, it's name I don't recall.

So we took turns, us two control liners and Jim's 50cc 3-D ARF. I pitted for Wayne, so as a result I didn't get many opportunities to swap props, but I did try a couple. And he and Chris both timed my laps and spotted the planes attitude, which I had been needing in order to progress in trimming it. She flies perfectly with tight lines, whether on too slow laps, too fast laps, or just right. Even flying too slow upwind, it's tight on the lines. Still working on that speed thing. It's an absolute pleasure to fly, I couldn't be more pleased with the old epoxy bomb. I was greasing wingovers like an expert. I still can't keep my loops the same size and in a groove. But my landings were pretty good without a single nose-over. My landing approach is not pretty though, with me running around trying to keep the lines tight after a last second accidental climb. I like pretty landings, but I need to work on that.

I got some good engine runs and some wonky runs too, but I logged a bunch of flights. I started out with my Master Airscrew 9x5 since that was my baseline so far. I launched my first flight at 11,600 RPMs and flew 5 head high laps at 5.6 seconds, and inverted at 5.4, but they only clocked 2 of those, and I'm not sure they were accurate. It ran a great rich-lean-rich break(as close to a 4-2-4 as this engine gets) and switched back and forth right on time.

I was thinking, and Wayne agreed, that swapping out the MA 9x5 for the APC 9x5 might get me the lap speed I wanted, 5.4 seconds or a bit less, and still run right breaking in the stunts. So I bolted on the APC while Jim had Chris flying his mid-engine rubber foamy RC trainer. He did very well with it, much better than me the time I tried it. I was glad to see him getting in on the fun. Wayne flew again and then Jim.

I was fueled up and ready to go when my turn came. Since I had the same pitch and length, I decided to launch at the same RPM as the last flight that I had done with the MA prop, 11,600. It took off and was doing what I had hoped, flying at 5.2 second laps and breaking in the climbs, doing some nice stunts. But around 2 minutes into the flight, it leaned out and started screaming around the circle like a rocket. I thought that was awful soon to be running out of gas, but I leveled off and turned fast circles waiting for it to suck air... and waited, and waited, but it kept on flying. So I risked a few loops, inside and outside, and it just kept on flying. It finally quit after 6:25. That was a long fast flight.

I thought maybe the APC, being heavier, might have heated the engine up up too much to run rich. So I launched it again richer at 11,100 RPMs. This time it flew flat at first at 5.4 seconds, but again, two minutes into the flight it leaned out, but not quite as bad. I had no break in the climbs, and it emptied the tank in 3:45, kind of soon. I wish I had a run time on the first flight with the MA 9x5, but I don't know what it was. Longer than 3:45 I'm sure.

I can try some more props next time. The APC didn't cut it today. The MA does everything right except it's a little slower in the flats than I want to fly. I still have a wooden TF 9x6 that's very light, and maybe won't heat up the engine into a lean run halfway through. It's on the list, but that's about it, except for a TF 10x4. I'm not even going to bother with my APC 10x4 unless all else fails. I just can't imagining it working if the 9x5 is too much load.

I can think of two things. I could try adding 2 or 4% more castor to the fuel and launch the MA at 11,800, 200 RPM faster than it's current best runs. and maybe the extra castor will keep it from going lean. That would get my lap times about right, and the castor would possibly keep it cool enough to stay rich. Or the APC launching at 11,100 with the extra castor might work too. That was the 5.4 second setting. It did run right for the first 2 minutes. I'll mix up a pint of Sig fuel with some extra castor to play with next time I fly. I didn't talk to Wayne about that. Hopefully Ken has some thoughts to contribute about that idea.

So the quest continues. Wayne, bye the way, insists that I'm probably not going to succeed until I get the uniflow fixed. I am going to cut the expansion chamber off a muffler I have and make it into a tongue with a pressure tap. Maybe that'll work without the uni pipe passing bubbles over into the pickup line. Ah well, the quest continues. Meanwhile the SS is a very fun plane to fly, even with the glitches.

Though I didn't get as much info noted as I had set out to do, I did learn that she's trimmed pretty much straight and level. And our exhibition was enthusiastically applauded by all of the visiting spectators and club members, and we just really really had fun.


Last edited by RknRusty on Sun Jun 02, 2013 9:20 pm; edited 1 time in total (Reason for editing : fixed tag)

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Re: Shoestring flying with a 1/2A prelude-6/2/2013

Post  Cribbs74 on Sun Jun 02, 2013 9:01 pm

Sounds like a great day Rusty, it's nice when it all comes together. What stands out the most is that you managed to grab a young guy and get him interested. If he is really keen on CL have him join the Forum. Let him know there is another active duty guy doing this..... lol!

I will be glad to supply him with a starter engine and a kit to build.

Ron
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Re: Shoestring flying with a 1/2A prelude-6/2/2013

Post  RknRusty on Sun Jun 02, 2013 9:12 pm

Cool, I'll point him this way. I was telling him about CEF today.

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Re: Shoestring flying with a 1/2A prelude-6/2/2013

Post  pkrankow on Sun Jun 02, 2013 10:27 pm

Sounds like a good day to me!

Phil
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Re: Shoestring flying with a 1/2A prelude-6/2/2013

Post  Mark Boesen on Sun Jun 02, 2013 11:28 pm

Hi Rusty,

Nice flight report! I think you've become a stunt flyer...trim, trim, trim, lol! To me that was half the fun, making the machinery run and perform exactly like you want it too!

The APC is a more efficient prop (some say slightly underpitched) so its not putting as much load on the engine, thats more then likely why it 'running away.' I think you're there with the right prop, maybe try a wood zinger 9x5w (w=wide)

And yes castor is a tool used by stunt flyers to help control runaway. I'd suggest 22-23% oil...what do you have now?

You might also take a couple feet off of your lines, 58' lines for a .25 is probably better than 60' I'm glad you're timing laps, now we can see what you're doing. 5.5 is what a lot of experts strive for but its pretty hard to maintain line tension, i think you're right on the money at 5.25-5.3 S.P.L.

Are you running muffler pressure?

Also, i'm not sure what you're doing on the loops, but you need to fly thru them, what i trying to say is you need to consistently make very small corrections as you got the handle pulled back, not just pull back and hold it...



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Re: Shoestring flying with a 1/2A prelude-6/2/2013

Post  RknRusty on Mon Jun 03, 2013 11:12 am

Mark Boesen wrote:...The APC is a more efficient prop (some say slightly underpitched) so its not putting as much load on the engine, thats more then likely why it 'running away.' I think you're there with the right prop, maybe try a wood zinger 9x5w (w=wide)
Those Zingers on eBay are going later tonight. I'll consider buying those. I can probably get TF props in that size from my HS. I've been advised that the TFs are known to shatter.

Mark Boesen wrote:...I'd suggest 22-23% oil...what do you have now?
Sig Champion with 20% blend now.

Mark Boesen wrote:You might also take a couple feet off of your lines, 58' lines for a .25 is probably better than 60' I'm glad you're timing laps, now we can see what you're doing. 5.5 is what a lot of experts strive for but its pretty hard to maintain line tension, i think you're right on the money at 5.25-5.3 S.P.L.
I have a new line set that needs to be assembled. If I cut down I can probably get the speed I need form the MA 9x5 that I've been using. That would be nice and convenient, the engine likes that one. 58' from handle to bellcrank, right?

Mark Boesen wrote:Are you running muffler pressure?
No not yet, for two reasons; one is nose weight, but I've decided to make a tongue muffler with a tap. The other reason is that I never got my uniflow to work. The feed tube sucks up the air coming in from the uni vent and spits it into the feed line. That may be less of a problem with the pressure line connected. If not, I'll have to shorten the internal end of the uniflow line so it can't pass air over to the feed line.

Mark Boesen wrote:Also, I'm not sure what you're doing on the loops, but you need to fly thru them, what i trying to say is you need to consistently make very small corrections as you got the handle pulled back, not just pull back and hold it.
I'm flying full sized loops, no more of the 1/2A style tight ones, except when I make a mistake. But it no longer coughs even if I do that.

Thanks for the tips,
Rusty

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Re: Shoestring flying with a 1/2A prelude-6/2/2013

Post  Mark Boesen on Mon Jun 03, 2013 11:19 pm

[quote="RknRusty"]
Mark Boesen wrote:...The APC is a more efficient prop (some say slightly underpitched) so its not putting as much load on the engine, thats more then likely why it 'running away.' I think you're there with the right prop, maybe try a wood zinger 9x5w (w=wide)
Those Zingers on eBay are going later tonight. I'll consider buying those. I can probably get TF props in that size from my HS. I've been advised that the TFs are known to shatter.

I used to use/love Rev-ups and old Top Flites, the Zingers are not bad, a lot of guys will lightly round the 'squarish' leading and trailing edge.

Mark Boesen wrote:...I'd suggest 22-23% oil...what do you have now?
Sig Champion with 20% blend now.

Use the chart below for adding caster to 20% oil content fuel:



Mark Boesen wrote:You might also take a couple feet off of your lines, 58' lines for a .25 is probably better than 60' I'm glad you're timing laps, now we can see what you're doing. 5.5 is what a lot of experts strive for but its pretty hard to maintain line tension, i think you're right on the money at 5.25-5.3 S.P.L.
I have a new line set that needs to be assembled. If I cut down I can probably get the speed I need form the MA 9x5 that I've been using. That would be nice and convenient, the engine likes that one. 58' from handle to bellcrank, right?

I'd measure what you have now and go 2' shorter, if you at 60' (actual line length, eyelet to eyelet) and reduce by 2' you'd be pretty close to 5.3

Mark Boesen wrote:Are you running muffler pressure?
No not yet, for two reasons; one is nose weight, but I've decided to make a tongue muffler with a tap. The other reason is that I never got my uniflow to work. The feed tube sucks up the air coming in from the uni vent and spits it into the feed line. That may be less of a problem with the pressure line connected. If not, I'll have to shorten the internal end of the uniflow line so it can't pass air over to the feed line.

At this point i don't know i'd worry too much about muffler pressure, if you and where you're flying is ok with noise. I think the biggest issue was getting the needle dialed in and i think you have. I like the idea of taking the larger of the two mufflers and making a tongue muffler, might be a fun project.
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Re: Shoestring flying with a 1/2A prelude-6/2/2013

Post  RknRusty on Tue Jun 04, 2013 10:34 am

Mark Boesen wrote:I'd measure what you have now and go 2' shorter, if you at 60' (actual line length, eyelet to eyelet) and reduce by 2' you'd be pretty close to 5.3.

I rechecked my line length. I was wrong, they are 61' eyelet to eyelet. Longer than I thought by a foot. So following your recommendation, I should cut them to 59'.

I assume the speed chart above is from eyelet to eyelet.

Just for the sake of AMA contest rules, is the total length supposed to be measured from the leadout hardware or from the fuselage? I know Ken has told me before, and I will look it up.

Once I get my line length right, I should finally be in business, because the TT seems to run perfectly with the MA 9x5. At least until the 100 degree weather changes the engine performance. Hopefully that will only be a needle setting and not another prop hunt.

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Re: Shoestring flying with a 1/2A prelude-6/2/2013

Post  Mark Boesen on Tue Jun 04, 2013 10:43 am

I think id still go 58'
AMA...is any .015 up to 70' or 72' max?
R u thinking contests????
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Re: Shoestring flying with a 1/2A prelude-6/2/2013

Post  RknRusty on Tue Jun 04, 2013 10:59 am

Mark Boesen wrote:I think id still go 58'
AMA...is any .015 up to 70' or 72' max?



...R u thinking contests????
I'm a Loooong way from doing as well as second from last place.
But I want to keep everything AMA certified.
I'm itching to get back out there. I gotta say, having a pit partner made things so much easier. The stooge is a nuisance and someone else to worry about the stopwatch and keep track of equipment is nice too.

We're in the staging and preparation portion of our upcoming beach vacation, so I might have to sneak away to fly between now and the first of July. And that means rushing,which I do not handle well. But I can probably go by myself on a weekday or two before we go. Lucky for me, saltwater fishing is my second hobby. But right now, it's not what's on my mind. I ain't dreaming about fishing as I drift off to sleep at night.

Did the Huskers win their regional? Carolina did, in two games.

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Re: Shoestring flying with a 1/2A prelude-6/2/2013

Post  Mark Boesen on Tue Jun 04, 2013 10:08 pm

I think you'd be surprised, you'd do very well flying Novice class or beginners class.

The Huskers had a really killer schedule, one of the toughest in the country, and entered Big Ten play with a really bad record. They played well in conference (tied 2nd) and almost beat Indiana for the league tourney, but because they were one game below .500 they didn't qualify...but Illinois who finished mid pack in league, playing non-conference patsies got an invite!
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