lgmac

Hi,

I have a Goldberg Eagle plane I built from kit. I stuck a o.s 40la engine on it because I had it lying around. According to the manual this engine is sufficient, and is in the middle range for this range. I am finding that's it's barely enough, and I don't think I'm getting the RPM's I should be. If I open the throttle all the way, the engine is a little sluggish to rev up, as if I where moving the stick on the controller a little slower then I actually am. I have tried adjusting the needle but turning it more or less, just take away power. My question is, what are some factors that can cause the engine to not run optimal?

Age of fuel?
Spark plug?
tubing or filter jams?
cleansyness of the engine?
improper break in?
anything else?
wheel size?

Thanks. Maybe it's just not as powerful as I thought but yesterday for example there was a dip in the grass and the plane did not have enough power to pull itself out of this dip, and I had to go get it, just seems to weak. Thanks for any tips.

JohnBuckner

My Feedback: (1)

First and foremost, what size is your prop??

Also yes wheel size can have an effect depending on what type surface, another big question?

finally how many turns from fully closed on the needle valve are you starting out with??

John

lgmac

I was using a 10x6 prop, but recently replaced it with 11x6 in hope that a bigger prop would pull more air, and give me more power.
The front wheel is 2 3/4, and the backs are 2 1/4, the plane does tip upward a bit because of this.
It can take off on short grass, if it nips the grass with the prop at all then I can't gain enough speed.
It's turned 1 1/2 turns from being fully closed (the suggested amount in the manual). When fully throttled up, turning the needle in either direction it seems to lose power.

JohnBuckner

My Feedback: (1)

OK first you cannot prop your way into a hgher performance just by increasing diameter or pitch that will only load the engine where it will barely run. An 11 x 6 on a LA 40 is a terrible idea and bound for certain failure. 10x6 is even more that what I would suggest. Much better with a 10 x 4 or five period. You are likely down several thousand in RPM. With that 11x6 I am surprised it had the power to roll down into that hole much less out of iit.

The Eagle if you built it according to plans and did not start reinforcing where reinforcing is unneeded is a fantastic flyer on the power of an old .35.

Dude order some 10x4's and some 10x5's now then find some help in flying this airplane but just as importantly help in operating and adjusting the engine.

John

JohnBuckner

My Feedback: (1)

One and a half turns from closed is about where I would expect it to be after tuning but you need to open a full two turns for the initial start of the day and after starting the the needle is adjusted in to find peak and only then backed off a few hundred. This can be done by ear or a tach or the method I use called pinch tuning that is very easy but not the same a using a tack or just by ear.

John

RBACONS

My Feedback: (3)

Might be a dumb question but have you verified (with the engine not running) that at full throttle, the carburetor is fully open? Also, it would be helpful if you know someone with a tachometer so you know how many RPM you're actually getting at full throttle.

JPMacG

My Feedback: (2)

I have an Eagle II with an OS 40LA myself. That engine is strong enough to fly the airplane very well.

I recommend that you find someone with experience tuning and running glow engines to help. Stop by at a local club and ask for help. Most modelers will be happy to give a hand. Working out problems is much easier in person.

If the prop is cutting grass then you will need to get larger wheels or mow the grass lower.

jester_s1

Agreed on the prop suggestions, and I'll add that you should consider bigger wheels. 2.75 -3 inch wheels will handle the grass better.

lgmac

Thanks everyone. I'll change the tires, the back ones look too small. Sounds like I was wrong with the prop, and I will put the 10x5 back on. The manual said I could use 10x5 or 10x6 which is why I did that. I do have a club about 15 - 20 minutes out but I haven't had much luck with the people there. The owner of the property is kind of a dick, and I don't know any of people that go their, pretty much strangers. They also require some insurance to fly there, which I didn't know existed for RC planes. I have found a friend who let's me fly at his place, it's a lot easier then dealing with the club rules. However I will be going to the club when I'm done with my p-51 mustang to ask for help because it's harder to fly and I've put a lot more money in to it. Sorry for trailing off there, thanks again, I'll try all your suggestions.

lgmac

RBACONS, yes the carb opens full and I have it set so I can trim it closed to shut it off.

JohnBuckner

My Feedback: (1)

Get rid of that 11x6 which is like a ball and chain wrapped around your airplane and get an APC 10x4 or 5. I have two airplanes that have the LA 46 and those engines are great using 10x6 but those are .46LA's, your 40LA is going to have a problem with anything more than a 10x5. You went the wrong direction in prop selection when in another thread you said I believe that you originally had a 10x6.

John

CafeenMan

Any club will require you to have insurance. Insurance is why most people join the AMA. The insurance is included with membership. I don't remember the exact yearly fee but It's something like $60-$65 a year for an adult. And it's definitely worth having. Think about the lawsuits you could have if your plane hit someone.

The best way to tune your engine is to have somebody hold it straight up with the engine running at full throttle. Turn the high speed needle in until you hit peek RPM. You should be able to tell by the sound. Then back it off 2-3 clicks. That will put it just a tiny bit rich for normal flight and max RPM for climbing.

After test flights if it leans too much then back it out a couple more clicks.

I think a 10 x 5 prop will be your best bet. An 11 x 4 may work well too. Any time you have a new plane you should test all the props you have that the engine can turn happily and decide on the one you like best. After you're experienced enough you'll know what range of props to try and which ones you won't even consider based on the type of plane.

For example, you wouldn't put a real low pitch prop on a P-51 even if you know the engine would like it. It's just not the right kind of prop for the plane.

But sport planes can fly a lot of different ways because they tend to be kind of generic. You can have a little bit faster plane if you're willing to give up climb ability. It will still climb but not as well.

Or you can have a plane that climbs great if you're willing to give up top speed.

Or you can shoot for the middle.

Just experiment. Give each prop a couple flights unless you know you hate it and then one flight is plenty.

Gray Beard

My Feedback: (-1)

I fly with a couple of clubs that don't require AMA membership but most the guys belong anyway just for the insurance. At any club the members will all be strangers until you go there a few times, some will be buttheads and some won't, just like anything you do.
If your having trouble with an LA engine you really better go to the club for some help and lessons. Most clubs will allow a new pilot to fly with an instructor or member standing with you until your AMA membership is activated, that usually takes a couple weeks. I remember flying at a couple clubs before my membership came through, they are pretty understanding.
I used nothing but the LA series of engines for a couple of seasons, the .46 though. I was never a big fan of the .40 but have a couple from trainers I had been given over the years. OS finally quit producing the .40, it was way under powered compared to the .46 but it will work on a lot of trainer type of planes and anything not requiring a lot of pull.
Learning to tune an engine is better learned with a hands on instructor then on a web site. We all have our own ways, Johns pinch testing is a very popular one and it works very well. He has posted the how to several times over the years but a hands on instructor will be able to tell if you have the low and high ends adjusted correctly.

jester_s1

On the club topic, what's exactly wrong with the property owner? Is it that he cursed at you the second you walked up and asked about the club, or it is that he didn't do everything in his power to help you when you showed an interest in flying? You have to remember that RC guys tend to be introverts, or at least not people people. Some are quite impatient with guys they think are going to waste their time too. That doesn't mean they aren't willing to help, but it does mean that you have to show yourself to be serious enough about learning to do the hobby to make it worth their time to help you. It also helps if you present yourself as a guy who will respect the rules and customs of the club so that they know you won't be a nuisance later. One of the ways to present yourself as that guy is to ask someone about joining the club. Don't complain about the dues and the AMA membership you'll need, and don't complain about the rules. The rules are there for safety and to keep everyone out of everyone else's way.

I can tell you from some experience being on the other end of this conversation (being the established club guy) that there are enough annoying little punks that show up and take an interest in the hobby that it truly requires some patience to keep being nice to newbies. I still do it anyway, but it's downright common for new pilots to show up and think the club is supposed to drop everything to help them. The same guys break the safety rules and are inconsiderate toward the other pilots, they complain about policies or about events that don't interest them, and such guys often think they are doing the club a favor by paying their membership dues. So, FWIW, it will help a lot to show up and ask someone their name, tell them you are new to the hobby and very interested in learning, don't act like you already have it figured out, and let it be known that you are willing to spend money on dues and AMA membership if it means having a good flying site and some instructors to help you. I think you'll find that the fellows get a lot friendlier after that.

lgmac

I have only met him briefly once. I don't think he actually is in to the hobby himself, he just happens to own a perfect plot of land for it. While he is obviously nice enough to allow a group of people to fly electric and nitro planes on his property my one encounter with him was very unpleasant. You have to drive through his property on a pretty bumpy dirt road that goes by his house and barn to get to the field. Last time I went, he came roaring down the road in his truck and start yelling at the people on the field because apparently I had driven too fast on his road. I was going between 5 and 10 mph and this road is pretty much in a field so there is nothing really to hit. I said I was sorry so he knew it was me, but he didn't seem to care. He said something like I don't want to have to tell you guys again, and then stormed off. Then another member on the field said, we have two rules, have insurance and don't piss off the land owner and told me I couldn't fly till I got the insurance. I was kinda shaken up, I haven't been aggressively yelled at for a long time, and wasn't aware of these rules in the first place. In all that visit left a horrible impression, plus I had two friends with me and we were like lets get the f out of here and found another place to fly. I have talked with some members and yes the majority of them seem nice, some even let me borrow some tools to build my plane and give me spare parts. So my beef is with the property owner only, not the members or the rules. I understand this hobby needs to be taken seriously because the planes can cause serious damage, especially to a person. I will get the insurance, it's pretty cheap after all and I will need help down the road. Don't worry i'm not one of those punks.

JPMacG

My Feedback: (2)

In my experience that is very common. My club has the same deal. The land owner wants us to crawl past his house and barn. Even 10 mph is too fast. So we do what he wants. Otherwise he would close down our field. Another club in this area, different land owner, has the same deal. It seems to be the nature of the situation. People who own large areas of land, particularly farmers, tend to be very protective and very controlling of their land. Flying fields are hard to come by and expensive to prepare. So we do whatever it takes to keep the landowner happy.

jester_s1

Yeah, that doesn't sound so out of the ordinary at all. These old farmers and ranchers are a crotchety lot to begin with, so you probably caught some flak that had been building up for a few weeks from other guys barreling down through there. The club is extremely lucky to have a free patch of land to fly on, especially if it's a good one. So your bad experience was one of bad timing plus showing up without knowing the rules. Neither were 100% your fault, but that's just how it is sometimes. I'd say give the club another shot. If most of the members seem nice, you'll probably fit right in once you learn the quirks of the group and make nice with the landowner.

JohnBuckner

My Feedback: (1)

This is in total reinforcement to what JPmac and Jestor just posted. I must have missed this situation perhaps you were talking about it in another thread, anyway lgmac you have no "beef with the property owner".

It makes no difference how far you can see on an open field if he wants you to crawl at one mile per hour then that's what you do. Dude without his generosity you and your club have no place to go, its that simple. Change your attitude and return to the club with a bit more humility and this very well could be the key to your ultimate success. Otherwise its likely you are just passing through.

John

ETpilot

Hummmmmmmmmmmm.

jaka

Hi!
My experience from flying R/C for nearly 40 years is that the OS FP .40 or LA .40 is very capable of swinging 11x6 props. That is flying from sea level. Especially so if used in a high wing trainer like the above mentioned.
Whats importat is that you use the correct prop brand. I have said it before and say it again...there is a vast difference in performance between prop brands and this is a fact many newcomers don't know.
If you want good performance there is no better props than British made RAM, German Graupner G-Sonic or American APC props.
If you use MA white tipped props I can understand your troubble taking off. MA "Scimitar" props are somewhat better though.

It's also important to use the correct fuel,glow plug and not using a large plastic spinner (Balancing problems) and also important...use a Alu spinner nut and suitable plastic mount (Dave Brown makes one of the best). Screwing down an engine to a warped plastic mount t (most are) is not the best way to treat an engine as the crank case easily gets warped that way.

Fuel for your engine should contain 5-15% nitro and around 20% oil (some percent Castor oil).
Glow plug should be OS 8 or Enya 3.
And most important....to set the engine you should rely on your ears!!!!! Hold the nose of the plane straight up and set the high speed needle so the engine rews max rpm...then back off some rpm. How much?...Well you learn that by experience or by getting help from more experienced flyiers in a club.

The small hole up front in the carb is the idle air intake hole and should be set half open . If the engine hessitates when you give full power either open the idle needle some or close it. The OS .FP or LA .40 carb is not that critical on idle needle setting and it runs just fine most of the time with the factory setting (idle hole half open) , at least at sea level. The full speed needle on the other hand must be set
every time you go flying!