Here's how my day went yesterday. I was able to maiden my CMPro Extra 330L, and it is one hell of a plane. I had a blast flying it. The wind was a little strong today (13-19mph), and made approaches a little hairy. I flew twice and had great success on both. On the second flight however, I lost power (engine was still running, but not nearly what it should have been), and didn't know why, so I landed. As soon as the plane touched down, the engine died. It turns out I blew my glow plug?? It is a brand new engine/plug, so I figured I had it a bit to lean. I took her up a third time, and it seemed like she bogged again so I came in for an emergency landing (my wife said it sounded fine). I didn't want to risk a deadstick, especially in that wind, so I brought her down as best I could. The approach was horrible, and I knew the landing was going to be bumpy. Long story short, i ended up landing in the grass, and there are a bunch of potholes in it (this is the first time I have flown at that field, and didn't realize just how deep the potholes were). When my wheels touched down, my left gear hit a pot hole and collapsed. I was pretty bummed to have a successful maiden, and a "crash" all in one day. I figured it was better to do a "controlled" emergency landing rather than test my luck at circling again. Well, it turns out that my glow plug was just fine, and I psyched myself into thinking the glow plug blew again. I was really bummed when I found this out. Oh well, it could have been soooo much worse. I have already fixed the gear, and she is ready to fly again. Before I do that, I want to figure out what is wrong with the engine if anything.

I assume that I was lean, and this is why my plug blew (wire burnt). Do you guys have any other idea's or suggestions for me so I don't run into it again? The engine is a OS .61fx and I am running a 12x6 prop on it. I run 15% nitro in it. I did rich-en up engine on the third flight, but it still seemed to me to have lost power after 3 or 4 minutes.

Is the tank padded? Vibrations might be causing the fuel to foam up which would make it run lean

The tank isn't padded, and I don't know how I would pad it. It fits into it's "holder" with no gaps all the way around. I could add padding to the tank in the front and back, but it would still sit in direct contact with the airframe in the middle.

One thing to keep in mind here is that when an engine is still fairly new glow plugs can just blow. This is because new engines actually take a fair bit before they are broken in completely, definitely more than the 1-4 tanks of fuel that most manuals call for. There is nothing wrong with this as it's normal. But as the engine continues to break in small flakes of metal will be in the fuel/exhaust residue. These small metal flakes can get up in the coils of the glow plug and cause it to blow out.

This is normal and something that accepted as you run a new engine. It doesn't happen with every new engine, but it can. There's nothing you can do to prevent it, so just change out the plug and keep flying.

Hope this helps

Ken

bonebreak:

Sorry about the mishap.

MinnFlyer just nailed it!

May be an isolated second small tank feeding from the main one, just to separate bubbles?

Some good articles with info about glow plugs:

http://www.lcrc.org/stu13.htm

http://www.scootworks.com/rdrc/gloplugs.html

http://www.holdfastmac.com.au/howglowplug.html

http://www.horizonhobby.com/Articles...ArticleID=1251

Regards!

Any idea why I would have lost power on the third flight. The glow plug was still in good working order after I took it out, but I swear I lost power. For the first couple minutes of the flight, the engine was strong, but then lost some of it umph. Maybe the bubble thing again (I would think I would gain a bit of power if it was lean and still running)? Would it help to put padding in contact with the tank even though it would still contact the airframe?

An engine will increase RPM as it leans out, but only to a point. Once it becomes TOO lean, RPM will sag and you could easily damage the engine due to lack of lubrication.

How is your cooling ? Remember engine cowls need an outlet area about 2 1/2 times the inlet area. IF thats marginal, and you are breaking in the engine, and you think your tank is a tad low or making bubbles, those will all combine to get you. And if the prop is to big, the engine won't drink enough fuel to lube itself, and it will generate too much heat overworking. So there are 4 issues to check for.

Welcome to Baxter field! Are you new to Moore? I am a member there, and I was out there yesterday evening for a couple hours. What time were you out there. I flew my extra yesterday till the sun went down. What time were you out there.Our South end grass area is bumpier than we would like for sure. Sorry about your landing gear. I had a power problem too with my 55 ax. I deadsticked in once as well. If the weather is nice this weekend, there will be plenty of club members there to help you figure out what went wrong.

No, I am not new to Moore. I have been in Oklahoma for about 15 years. I had been flying up at Hefner Lake due to my buddy flying up there also. He has since moved to Florida, and now I am all by myself. Baxter is alot closer to me than Hefner, and I like the feild alot. The runway is MUCH wider than Hefner. I actually landed on the east end of the feild, and it's like a four wheel drive course over there . I was out there about 11am to 1pm. It was just me, my wife, and my four year old boy. I wish I would have waited until later in the evening because the wind died down quit a bit. Oh well, I had a blast anyways. The Extra is alot of fun.

How much is the membership at that feild? I will probably end up flying there from now on since Hefner is so far away.

Hefner has a nice flat grassy area to deadstick, but I hate all the trees. I can watch the planes from the window here at my office at 63 and Hefner Expressway. I think membership is $50 for a year. http://www.baxterfield.com/

Now that I have flown at Baxter, I like it much better. I do like the grass for deadsticks at Hefner however. Do you know if the feild is owned by the city or is it leased by an individual/club? As much as I would like to be part of a club, my work schedule would really hinder me making it out to any functions. If it is leased by someone, then I need to pay my dues to fly there.

We lease it from the city. We recently got a 10 year lease agreement for it too.

If your loosing power in flight I will go with the cooling problem or too lean too. A lot of problems with the way an engine runs in a cowled plane are caused do to poor cooling and the engine over heating. Like Ken mentioned, a new engine will sometimes get crud or flakes in the plug wire and short it out. Some engines come with a mystery plug installed for break in too and tend to burn out quickly.

I have since cut out the front of my cowl, and opened up the bottom where the exhaust sticks out a bit more also. It is now twice+ as open as it was in the front and the bottom. I was wondering if you can cut to much of the front of the cowl to where it captures air and slows the plane down. I assume not since it can easily pass through the bottom, but am curious none-the-less.

Cutting the front of the cowl will cause it to overheat. High pressure in the cowl will stop airflow. You want low pressure in the cowl so air will flow through the inlets. But since you have already done it, and you say you have a 2 1/2 to 1 ratio, you should be OK.

I've actually closed down inlet area to increase airflow before. The Bonanza pic shows how it was done to establish the correct ratio.

Bonebreak, I was having the same problems with an Os 40 La, there were some shavings of metal inside, i went through 3 plugs in 3 flights, anyway through this site with the aid of fellow modelists, i cleaned out the engine, ran it a little richer and i've been running with the same plug for 2 weeks without a problem. Everyhting was pretty much the same as you, new engine, 15%nitro, OS no. 3 plug, i'm using an OS no. 8 and havent looked back.
Hope this helps
Will

Thanks. I am going to have to close up the front of my cowl, and open up the bottom a little more to get the proper 2 1/2 to 1 ratio. Here is a picture of my cowl. Please let me know your opinion on what I should do from here. I could easily add additional holes to the left and right of the bottom center hole also.

First three shots are of cowls on two Extras, the big one is a gasser and the other one is a glow powered Extra with a YS 1.20 FS for power. They are both opened up with a lot of over kill on the bottom. If most of the engines head is sticking out you don't need as much air flow but both of these planes have had different engines installed at some point so the cowls were opened as needed. The yellow Sukhoi I scratch built and for the most part only the head and muffler are sticking out. As set up I was going to fly the plane and see if it needed more air flow and open the cowl as needed. As it was it never over heated due to air flow over the head so the cowl worked out fine. I have another shot of a scratch built Krier Kraft Bipe with a lot of air flow going in like on the Suk but the head was sticking out enough that it never over heated. Looks like you have plenty of out flow but you opened up the front way too much.

I decided to go ahead and re-fiberglass the front of the cowl, and start over. I need some advise on what I should do for the inlet now I will have a blank slate.

Look up at the photos!