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General control line discussion => Open Forum => Topic started by: Dan Berry on October 27, 2012, 09:02:06 AM
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This what I wound up with.
Kit-built Oriental from Brodak. New landing gear. Tower 40 on the nose.
39 oz w/ tip and tail weight.
It is transparent red Ultracote, metallic teal Monocote and KlassKote white epoxy on the nose.
Hasn't flown yet. The engine is some kinda tight and I could not start it last evening. Today it will get bench run.
Guys, this is a lot different than building a Free Flight plane. I have a REAL understanding of what my brother Clayton must have gone through to get anything built----try tying a brick to one hand then build a plane. How he did this one-handed is beyond belief.
Hopefully I can get it flown this weekend. Weather might be icky. The ElDorado contest is next weekend and I sure wanta fly it before then.
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Oriental looks great. Just don't push the Brodak .40 too hard. It takes time to get them broke in properly. They are supposed to be tight at the top of the cylinder. Remember, do not turn it thru with out a prime or some oil.
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Clayton would be pleased with the transparent monokote, he liked finishes like that. Looks like a good build. The Tower 40s are good motors with true chrome ABC liners instead of the OS nickel liners. A Tower should run pretty much forever.
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Coming up on a quart of fuel through it. I've been running it pretty rich. It's tight. I ain't used to starting them by hand nor letting them run this long.
I have discovered that the tongue muffler doesn't make a lot of quiet.....
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I once did a test flight with a brand new plane in crappy weather just to get a flight on before a contest. Only took 4 days to fix so I could go to the contest.
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Wind will be better on Monday.
I put a quart of fuel through it today. More will go through tomorrow.
I did run out my bench tan, added four oz fuel and ran it out again----8:15. This was a pretty rich run.
Question: Does leaning it out use more fuel with the added RPM?
I am not used to running a motor this long. I did a couple of 26 second runs with my Nelson 36 at the NATS this year......
I don't EVER want to do THAT again.
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Stop running your engine rich! It'll beat the rod bearings out, if the pinch is significant. An ABC/AAC/ABN engine should be run in a rich 2-cycle for break-in. They need to get up to temp, but not heavily loaded. A 10-4 should work good for bench running. Leaning it out will run faster but longer. Using fuel with increased oil content will reduce the run time, especially if it's castor oil (assuming same nitro content). The 10.5 x 4.5 APC should be a good prop for first flights. I'd also try the TT 11 x 4.5 for sure. I'm not a fan of tongue mufflers. D>K Steve
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Looks great and the weight is right on.
Allen
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Does it really need such a big fuel tank? That this would fly 12 minutes or more with an OS 40.
Great work on the plane.
I'm glad I use OS's. No trickly break in procedures with chancy success. Just a tank or two on the bend and go fly.
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"Guys, this is a lot different than building a Free Flight plane."
Interesting, it is different but all the FF skills and wood discipline sure give you a head start. Looks great Dan.
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Randy, it doesn't looks so good up close. A thermal won't make it look better.
Hinges, leadouts, permanent alignment, covering over compound curves....imagine doing that one-handed. Then, take your one good hand and put it near that spinning prop.
Paul, I'm thinking the same on the tank. I don't have immediate options other than not filling it to full. I'm thinking that a smaller tank will be in order. Or, I could use the country-boy method and squeeze this one to smaller capacity. Plans showed a Fox 35 and a four oz tank.
I'm glad the weight seems OK. I have no reference point. It does need 1.5oz tailweight to get it close on the balance. 39oz includes tail and tip weight of 1oz. I'm guessing that moving the motor back be a future option. I'll wait to do that after I need to re-build some part of the plane.....
I thought the wood selection was pretty good in the kit. Die-cutting 1/4" six-pound wood isn't such a great idea. Fin and stab as built are a bit smaller than what was 'cut'.
Off to run the engine some more. leaning it out is in order.
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Partially filling a tank tends to make stange things happen. I would take few test flights with a full tank and shorten it if proves to be way too big.
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I am looking at 3 minutes run on 35cc fuel.
The plane has a 4.5oz tank.
I'm thinking I need to get a 3.5oz tank.
I had no idea it would be so miserly but it has a tiny venturi compared to my experience with similar displacement engines on my FF stuff.
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Five flights so far on my Oriental.
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At our altitude in Philadelphia, I use 4.5 -5 oz's of 5% fuel in my FP .40's using the large venturi to complete a pattern. The large is .270. Dan's tank size sounds correct with the tongue muffler assuming his venturi is nearing this size as well. This is my situation using one .010 head gasket. Seeing the Tower .40 is darn close to the FP I would say his tank size is correct. The Tower .40 however uses a slightly different head design than the FP. Seeing that his engine is new, I'm assuming the launch will be slightly richer and your certainly going to use more fuel. In my comparisons that I've done, I've found the LA .46 even though larger is more conservative on fuel. I found the LA.40 to use much more fuel than the .46 requiring a tank size of 4.5oz's. I have one FP with a Randy Smith tongue (holes drilled out) 10.5 x 4.5 prop and that engine consumes almost 5 oz's of fuel per pattern. Ken
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On my test stand I'm doing 5 minutes with two ounces of fuel.
I'm wondering if my venturi might be a bit small.
I must guess that I need to acyually fly the thing to find out if it has enough power.
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Dan,
Glad to see the oriental finished, Clayton would like it. as Steve said. Looks a lot like his models, sure do miss him,
Keep up the building
Will
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Most people run too big a venturi on an FP or Tower 40. It will burn a bit more fuel swinging the flight prop vs a smaller breakin prop.
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The venturi that I have has a .25" inside diameter. The spray bar is 5/32 diameter.
I had recommendations for a .270-.280 diameter.
I'm thinking I need to find a drill bit.
Five minutes on two ounces just doesn't seem right. I must assume that it's giving up some power that I might need.
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I have drilled the venturi to a size I bit--.272 .
It took almost 45 secs off the 2 oz run on the bench. These are leaned out runs.
Mounted on the plane and run. It will beak 4-2 and seems to be close upright or inverted. It will fly tomorrow and I'll see if I need to shift the tank.
Another question: Is it my imagination or will it flood a bit with fuel in it while sitting on the ground. It has a tall tailwheel strut and sits close to level. I had it fueled but found myself unable to start it immediately because of an interloper. It didn't exactly have a puddle of fuel under it but it seemed to be loaded up a bit when I went to start it. I'm not at the point of one-flip starts yet but I had to clear it a bit. It's a uniflow tank. BTW, I AM supposed to cap the overflow on the bottom---correct?
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Sitting in a near level attitude will allow fuel to gravity flow into the spray bar until the fuel level is equal height to the spray bar. Try sitting the tail low off the edge of a table or lifting the main wheels up and see if the fuel stops filling the venturi. You may also be filling the venturi during fueling, a common problem with a tail high set up if you're fueling through the uniflo tube. And yes, you do have to plug the overflow before starting the engine.
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Five flights so far on my Oriental.
Looks nice Allen.
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.272 is a step down from the large FP40 venturi. The large venturi is .283. I prefer the .272. A good match for a plane the size of the Oriental. This is using a stock OS needle, smaller than a Supertigre needle, meaning the choke area will be larger. What fuel are you using. In Philly we use Powermaster 22%(50/50) %5. The new pink stuff works almost the same as the old clear stuff. 101/2x41/2 APC, a good choice. I run a lot of Tower 40s. They hold compression forever. Better than FP40s, which I also like. The true chrome lining in the Tower seems to last longer and retain compression better than the FP40 nickel. My latest profile uses a Tower set up similar to yours. Works very well with my cheater Magician, 48" Midwest wing, wider flaps, stab enlarged and moved back. An extra head gasket softens the break a bit. That Magician weighs 36 ounces. A bit less wing area. Your Oriental should work well. The engine has been bench run plenty. ABC engines need very little break in.
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I flew the beast today. It and I are intact.
First launch I had set to make a 2/4 break. I liked the way it flew. Inverted was nice. Did some inside and outside loops. It seems to have enough throw to be safe. Tried a half-hearted wing-over. Nope. No line tension up there. About 7 secs /lap.
Moved the leadouts back. No overheads again. Same laps speed.
Decided it could be faster after thinking about the 5.2 second laps that I read about. Leaned it out some and still had a semblance of 2/4 break. Faster but I wasn't gonna go overhead.
Leaned it out some more. Eventually I got it to around five secs/lap. Overhead was good on a wingover so I played with my version of a couple OH eights. I can blast my way through a beginner pattern with it as long as no geometry professors are looking at square loops.
Two ounces fuel went about five minutes. This is with the .272 venturi and a 5/32" dia spraybar. I'm thinking I could open the venturi a bit more--either a J or K drill bit. Fuel is 5% pop with 20% synthetic oil from RedMax. Lines are 65 feet. I have no head gaskets presently. Would they help?
The landing gear is aluminum for profiles from Brodak. I was over grass (where I'll remain for a while, I think) and the first landing deflected the gear out and up. Actually, all landings did this. Kinda perturbing. I thought it would hold up better. Clayton always told me to avoid a wire gear.
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Shorten your lines. Try 60' or 61'. Run a 50/50 lube fuel. Half castor and half synthetic. I bet if you shorten the lines your set up will feel pretty good. If you are almost able to do overheads with lines that long, you're probably close. Try a 101/2x41/2 apc prop. You might benefit from opening up the tongue muffler some. Definitely can open up the venturi, if you still need more power. You're not burning enough fuel. I don't know if your needle is larger in diameter from the stock OS FP needle. If it is. Open the venturi a bit. Definitely undersized choke area. These engines like to run on the fast side. A kinda wet 2 stroke on the low end, a leaner 2 stroke when power is needed. An extra head gasket or two will soften the break. Worry about that later. Tune to taste after you're getting enough power to feel confident in the overheads.
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Looks nice Allen.
Thank you Crist.
Allen
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Nice planes Dan and Allen! :) :)
I have both the profile and full fuselage versions kits I want to build this winter...
Hope they come out half as nice as yours.
Cheers,
-Daniel H^^