OS LA .15 Set up and Reliability

Tell us what you do to get the best performance from your engines.

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boiler
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Post by boiler »

Take it easy guys. We are all trying to help our competetors do better. I fly tanks and bladders. I have trouble with both. I have success with both. I'm glad to hear of fixes for engine problems which is what this thread is supposed to be about. The trouble is that some of us are so convinced that our fix is the best, that we want to argue the point when someone offers a different fix. Let's put out the helpful information to our competetors and let them experiment so they will be a target and someone to try to evade[B)]. It makes combat soo much more fun. When I go to the field to test fly (or to a meet since I haven't been to our field in months)I find it very boring without another plane to chase or evade.

Bob Loescher
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Post by montague »

Scott,
I sure am glad I'm not the only one who remembers the bladder crowd swearing up and and sideways that there was no performance increase, no RPM increase, from using a bladder. That it's a reliablity thing only.
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Post by thojo »

Technically, you do get a slight increase using bladders. With a bladder, you can set your needle a click or two leaner than with a clunk draw setup, which will give you a more optimum setting. Is enough to care about? Personally it still comes down to choice and what you are comfortable with. I fly mainly clunk tanks, I do that because I don't feel I'm as rushed to "get ready" when the 1 minute warning to 90 seconds is called. I fly, I return, I fill my clunk tank and I'm ready for the next round, instead of I fly, hope my carb isn't flooded, return, defuel any remaining in the bladder, wait for the warning, then fuel, then pinch, then get started...

There are advantages to both setups, it comes down to personal preference and I'd as soon leave it at that...

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Post by mad »

Lou, A couple of questions if you dont mind. 1. What is your glowplug of choice. 2. what is your fuel of choice. 3. What size are the screws in the backplate. 4. What is the part number for the metal replacement backplates you are getting and are the for a la 15 or another engine. 5 Thanks for the help. BUT You are enableing the thread hijackers to change your focus. Try this responce
that subject is not what this is about if you wish to start a thread about that I will discuss it there....



Kirk I have never called anyone out by name before. however I found nothing in your posts that will help me get my 15 running better. I wonder how many newbies you have helped with your posts on this thread. Just a thought.
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Post by Which_way_is_up »

Kirk, I'd developed a lot of respect for you through some of your insightful posts over the last year but clearly I don't have a clue as to what you thought this diatribe was suppose to accomplish.


And Scott,

Shame on you, for someone as thin skinned as you to have come in with that rant of yours, what in the world pulled your chain. Is this what we can expect from our new district rep?

Both of you obviously has some unresolved issues (bladder envy?[}:)])and unfortunately this isn't the local mental health dept. So just get over it!



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Post by Lou Melancon »

Michael,
The back plate screws are 2.6mm X 8mm. You could just cut down the 2.6mm X 10mm head bolts and use them, but I prefer to just buy a bag of the right size. I normally do not change the backplate screws because the socket head bolts pull through the plastic unless you put a washer under them. The aluminum backplate for the OS .15FP does not have the tendency to loosen that the phenolic one has.

Off the top of my head I do not know the part number but I have some in the original packing in my flight box so I will check and post tomorrow. You can also go to Tower Hobbies and find it in the parts listing section.

Most of the time I use PowerMaster 5% Nitro, with 18% oil which is 2/3rds synthetic and 1/3rd castor. If I use more more nitro I will often exceed 17,500. In cool dry air I have had to use 0% nitro and in high heat and especially in high humidity (the increase in hydrogen pushes oxygen out of the air) I have to go to more nitro to make rpms. I use a mix of castor in my oil because it has such good lubricating properties. If you look at the front page of www.georgiacombat.com you will find a good write up on the properties of castor oil.

Lou Melancon
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Post by EK »

A good thread Lou! I run 15% on a clunk and am right at the 17.5. I've found quite a bit of variance in RPM prop to prop so if I'm not at 17.5 will try another prop or two before mixing the gas or closing the barrel.

I had a bout with air in the line after the needle. I'd zip tied (hard mounted)the needle to the side of the fuse. Cut the zip tie and let the needle free float and the problem disappears. Now, I put a small zip tie around the needle and thread the bitter end through 2 small holes in the fuse leaving the needle about 1" of free play. Keeps the needle on the plane but fixed the problem.

Evan Wenger
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Post by Lou Melancon »

Evan,
Do you think engine vibration was transferring to the needle "shaking" it to the point it caused bubbles? Or do you think that the shaking caused the fuel line to move on the nipple allowing air to get in? Sounds like it might be the latter.

Lou Melancon
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Post by rdc767 »

With all the bitching and moaning about bladders you think they rule combat. HOW UNFAIR. Thats just not the truth.

Look at the "Marthon before Munice." 4 out of 5 non bladder in the top.
Current SSC point leaders 6 out of 7 non bladder.

I run both and see no advantage. Sure they hold a better needle on a well set up motor (no leaks). But if you don't practice alot you will fail. I think the people who really like bladders work very hard at it and deserve credit for there success.

Thanks Lou for the great article.
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Post by boilermaker »

The performance of a bladder is overrated. The statement that they yield 500 additional rpm seems to be based on unscientific observation and guesswork more than anything else. I fly clunk, because I don't want to invest the time and energy to get a bladder running right, and a clunk tank physically works well on my bat. I can get 17.5 without a bladder so I'm not worried about extra power. My observation, based on those I know using bladders, is that bladders tend to be more consistant in their good runs. But, that 17.5 limit keeps them from consistantly running significantly faster than me. The only real advantage I see in a bladder is that it's easier to hide in a wing, making designs like the cobra possible.

It even sounds like there's no correlation between NPS rankings and bladder usage.

I don't have a problem with flying my clunk against bladders because so far the time and energy to put into bladders doesn't seem worth it. Just as I don't mind flying my bat against a better performing cobra because I like flying home from a wing vs. wing hit with my engine mount still in place.

The only real drawback I can see is the intimidation factor for beginners. For those without the help to get bladders right, that system can be overwhelming. And without help many may likely give up on them. If that could lead to that person giving up on combat as well, that would be a huge drawback. The first person I fly with to really get it working right read everything out there on these sites and still didn't have it... luckily he's a persistant bugger and a few emails back and forth with Roy A. got him going.

So what is the point of this longwinded diatribe? I'm too lazy to use bladders, and I'm too lazy to break in my OS .15's as described. I still can get the rpm's I want (except with a non-sealed fp backplate).... oh and Mark is a persistant bugger that really gets his engine running well with a bladder, but sometimes I still fly home with engine running when he's walking back with two wing halves and an engine hanging by a tether.
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Post by EK »

Lou - I think the air was caused by the entire needle valve assm being zipped tightly against the fuse. (older Avenger modified for SSC). I'd replaced all the fuel lines, even changed tanks and when I cut the needle valve loose the problem stopped. I'm sure there is air in the fuel from the tank (how can there not be in an open system), but the soft mount seems to let the air pass on through without concentrating into bubbles.

Maybe I'm the only one who's had this problem. I mount my tanks farther back on the fuse than most.

Evan Wenger
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Post by sgilkey »

Roy, sometimes I wish you'd just zip it. As one who lurks on the forums taking snide pot shots, I get a hearty laugh out of you taking issue with me expressing my opinion, and my recollections. My position as district rep restricts me from expressing my opinion about the same way as your position as treasurer keeps you from taking cheap shots- not at all. As to suggesting that people get a life- physician, heal thyself!! You must have had something better to do than attack Kirk.

I have not run the LA enough to know if this applies to it, but I know on my FPs, they require a very unusual needling technique. I have not seen this on my 25FX,Magnum 15XL, or any others, so again, it may not apply to the LA. I need to start off on the rich side, and SLOWLY lean the needle in a click at a time (this is on suction, may not apply to pressure or at least may apply to a lesser extent). Let the engine stabilize and go another click lean. It is tedious, but essential for that first needle setting of the day. It will usually take me a couple of minutes to get to the lean setting on my first try. If you go lean, start over. If you try to quickly dial in the needle, you will go past the ideal setting to a too-lean setting, and not get your best rpm. i can't explain why the engines behave this way, but it is consistent across the more than dozen FPs I have.



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Post by Ed Kettler »

Maybe what we need to do is take the informational aspects of this thread, edit them together, and post a Technical Note so everybody can benefit, without having to wade through the whole thread. we need to think about whether these kinds of Technical Notes should be member only, or generally available. If they were member only, would the benefit of access to that information help grow RCCA?

Ed

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Post by thojo »

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">I need to start off on the rich side, and SLOWLY lean the needle in a click at a time (this is on suction, may not apply to pressure or at least may apply to a lesser extent). Let the engine stabilize and go another click lean. It is tedious, but essential for that first needle setting of the day. It will usually take me a couple of minutes to get to the lean setting on my first try.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

Scott, thats pretty much the way it is when using RNV's. It just takes a few seconds to clear the fuel between the needle valve and the carb. I normally pinch the line as I adjust the needle to clear out the line and get it where I want it... And of course, the longer the line between the needle and carb, the more this effect is amplified, so I try to keep the distance as short as possible...

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Post by Lou Melancon »

Ed,
At the risk of taking this thread in another direction I would like to answer your question about whether data like this should be in front of or behind the Members Only door.

I think it should be out in the open for all, members or not, to see and read. I do not think people become members for access to our secret knowledge. I think they become members to join in the fraternity and indicate they are serious about it by plunking down their $15. Folks who fly in contests are somewhat more interested in NPS than those who don't.

I think we will get more members by being open to all. We should keep our bickering conversations behind the "members only" curtain and put them on the Soapbox.

Lou Melancon
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