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Old 08-11-2008, 06:17 PM
pipercub123 is offline
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DA 50 engine decides to take a break while I'm flying!

I had 3 super flights with my Airwild Extra 260. Engine ran powerful and seemed to be good. It started easy and had a great idle. Took off for flight 4 with a full tank of fuel, good battery, and engine died after coming back around when plane was about 30' above center of runway. Tried to glide it in and she stalled about 10' and hit the rough short grassed area of a field shearing off gear, snapping muffler pipe, and wrecking my fuselage. Two dents in the wings, snapped wing saddle and motor box, and messed up cowling and wheel pants. My prop is okay and damage isn't too bad, but it's going to need to be rebuilt. I'm going with new balsa and ply instead of trying to reglue it.

What's good ply for rebuilding. Tower Hobbies has baltic birch which is cheap http://www3.towerhobbies.com/cgi-bin...?&I=LXBER6&P=0, but I'm thinking it's not good for planes. Than they have this http://www3.towerhobbies.com/cgi-bin...?&I=LXAS83&P=0 and this http://www3.towerhobbies.com/cgi-bin...?&I=LXAS78&P=0 which is probably the best as it's the most expensive.

Would balsa usa be better? As for the engine, I'm thinking of sending it back to DA to see if anything is wrong with it. The prop wasn't damaged so I doubt there was any crankshaft damage. The muffler is damaged though and if DA can't replace it than I can try to weld the stack back on. As for the wheel pants and cowl, I guess my plane won't look so good now. It'll give it a rugged tough guy look. If anyone asks what happened I'll tell them that DA happened.

Why would a great running engine suddenly quit? I don't get that from my glow engines. I even checked it after the crash and the ignition battery was good, all wires and switches were checked with voltmeter, plug looks okay, and I couldn't see anything out of whack.

I'm not happy with this DA, perhaps the problems could be something that I'm doing. My other gasser is a US 41cc engine and I've never had problems, luckily as I've heard bad about them. I haven't heard too many bad things about DA so that's why I went with it. I almost went with a 3W and I'm wondering how that would've done. I'm suspecting they have issues too. I've only had engine problems on the ground mostly, but I've never really had too many issues with flameouts in the air. I've had a few, but mostly from running out of gas. My DA50 was idling that day like it would never die out and had a super steady idle. I was at half throttle and I throttled up good for take off just in case it had gotten rich from idling on the ground.

Hmm, I love the sound of gas but I've never heard of electric motors flaming out.
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Old 08-11-2008, 06:59 PM
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Re: DA 50 engine decides to take a break while I'm flying!

Without a look at the setup it would be really hard to say what caused the flameout. My DA50 would only flameout when inverted. The problem was cause by my bad tuning of the engine. After my deadstick I turned the low needle out, rich, by 1/2 a turn. I did this based on information I found in some forum. Idle got better and no more flameout.

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Old 08-11-2008, 07:04 PM
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Re: DA 50 engine decides to take a break while I'm flying!

You know I love DLs and never owned a DA but, in all fairness, that doesn't sound like a problem you could blame on the engine. I'd have to think that something drove that issue other then the engine or any of its designed features. I know that some of these engines are tuned to run rich inverted and lean out in level flight but if that were the case it shouldn't have gotten off of the ground. I really think you need to investigate further before you get your plane back together and have it happen again. Oh, and buy a DL like I told ya in my PM. LOL No really, I don't think this one can be blamed on DA.
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Old 08-11-2008, 09:45 PM
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I had it, but then I lost it.
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Re: DA 50 engine decides to take a break while I'm flying!

Sucks but as longs as it's repairable that's fine.
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Old 08-11-2008, 10:34 PM
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Re: DA 50 engine decides to take a break while I'm flying!

That's too bad. Hope you're flying again soon.

Go to Midwest for quality woods.
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Old 09-15-2008, 10:47 AM
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Re: DA 50 engine decides to take a break while I'm flying!

Update:

I've been working on the 260 off and on and it's almost ready to go. The flying saw dust is coming to an end. I tried to solder my muffler back together with no avail. Has anyone ever tried soldering aluminum? There must be some aluminum brazing rods out there. I didn't have a butane torch handy for brazing so I was hoping the solder could've done it. All I had was Stay Brite solder I bought from Tower and that's not recommended for aluminum. Than I tried JB weld with no luck. I have welding wire for my MIG welder but don't have any gas. While heating the DA muffler with my torch, I buckled some of the pipe with a small flame from my oxy acetylene. Just what I was afraid of doing. That's really thin stuff for sure and being aluminum it's only harder to weld. I'm sure I could have migged it, but I ordered a new Silent Beauty Pitts muffler from TBM instead as I wanted something quieter than the stocker. I almost went for the Jtec large volume, but the $140 price was too much for me. That's extra money for me to buy a new prop balancer or go towards a CF gear and wing tube. I know the Jtec would be a bit quieter, but I figured to sacrafice for a little more sound and about 2 oz lighter. I'm sure it wouldn't be too muffled with the large jtec, but I didn't want to take the chance of too quiet as I like to hear the sound while flying. Now I'm coming up with ideas to lighten the plane to bring it back down to stock weight. I'm looking to loose 4 oz as I suspect I gained about that with the new muffler and heavier wood. I didn't make up for a little by leaving out some wood.

I'm looking at putting 3 large lightening holes in the motor box sides and four small ones on the bottom so I still have a way of mounting my ignition battery. I also neglected the 3rd layer of 1/16" ply that brings the landing gear bottom flush with the bulkhead and the balsa sheeting on the sides to contour the plane's sides to the bulkhead. I shaved down some of the bulkhead to smooth it out, but this was negligible. This made it a bear to cover and I'm slightly happy with the covering. I knew it wouldn't be a perfect match before I started, but taking out the sheeting and covering the bottom and sides with one piece without cutting a seam was seeming impossible so I cut a seam and tried to stick covering on covering. I needed to patch on an extra piece as the covering puckered. The covering I used was leftover from years back when Horizon started their Hangar 9 ultracote. I'm not sure what Airwild uses, but the stuff that I had was a decent match. So she's not as purdy as she once was, but it was a given that you'd see a seam. I'm thinking about some kind of a design to put over the covering seams to hide them. This is going to be my practice plane so it's bound to see a few more scrapes, maybe worse. I'm a bit fussy with my planes as I always want perfection, but this time I'm just glad she'll be flyable.

Construction wise she's almost back to original and then some. I used 5 ply wood and although a bit heavier it's a lot stronger. Perhaps too much, so that's why I wanted to attack the motor box with lightening holes. I'm a bit hesitant though as I don't want to take out too much and weaken it. Also I'm pretty sure that if Airwild thought it'd help taking out weight from the motor box, than they would've. I'm not sure exactly how much weight I'd save by cutting out 2 3/8" holes as I don't have a scale. I'm guessing about close to half the weight of a servo which if weight was so critical I could find other means of saving weight such as using a single lipo pack for the rx and one for the ignition. That's not as budget friendly though as I already paid for the Nimh packs and the battery share that's in it. So I'll most likely stick to the biggest weight issues and only spend money on issues that will result in the biggest weight loss. Two issues that I see are the landing gear and the wing tube. I'm considering drilling lightening holes in the landing gear to save some weight, but I doubt I'd be able to get close to the weight of CF gear. The wing tube will get CF as I'm too afraid to attempt drilling the wing tube with holes.

My main reasons for the weight loss is to get back to the original weight with the new heavier pitts muffler. If the pitts muffler doesn't muffle much, it's going to be up for sale. One plus I do like of the pitts though is that the exhaust stacks are bent back so they don't get caught on dirt and bend in case of a sheared gear, just what happened to my 260. I believe the firewall on my plane was damaged when the long stack on the stock muffler grabbed the ground. The force must have pulled the engine down before the pipe sheared. Now that's a lot of force on the engine and firewall. Either that's one strong muffler or I had a weak firewall. I'm leaning on that's one strong muffler. As for the gear plate shearing, I'd rather had the bolts shear. I decided to put the gear on this time with 4 nylon 1/4 20 bolts. I think this is plenty and I'm wondering if these would even break before pulling out the mount. Two might be enough but I was concerned with them weakening over time. I'm hoping I won't have to find out, but if it works as planned I'll be happy.

For those of you with the side mount mufflers, you may want to think about trimming that exhaust stack as close as you can to your cowl if you haven't already. The engine may be a bit louder, I doubt you could tell without a meter. I could be wrong though. I've heard of some gaining rpms doing this, I've never tried. If anything you'll loose some weight and reduce the chance of what happened to me happening to you. That long stack acts as a big lever. I would prefer cutting the stack flush with the bottom of the firewall and than using some high temp tubing to deflect the exhaust down. Obviously this way you get some flex and you still deflect exahust minus the big lever.

I'm not positive that it was the exhaust that helped crack my firewall, but I can't think of anything else. The prop was stopped level on impact and didn't even get a nick on it. The spinner tip had no dirt or scratches on it. The landing gear plate isn't tied directly to the firewall so I took that out of the factor. All I can come up with is that DA has one heck of a strong muffler. That took some good force! I'm glad I didn't get a crack in my cylinder.

Check out the pics guys. Let me know any tips I could have done patching the plane. I got a bit frustrated doing it so I didn't even bother rounding the corners of the patch and I know all patches should be rounded. I had one goal in mine, get it covered and fast! I'm thinking of stripping the covering this winter and covering it in a yellow so she's a bit brighter. Please don't forget to comment on the weight savings ideas and what I should lighten and what I shouldn't. Also, how do you think the nylon gear bolts will hold?

Thanks in advance and I hope I wasn't too long winded.
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Old 09-15-2008, 02:02 PM
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Re: DA 50 engine decides to take a break while I'm flying!

Have you determined the cause of the flameout?

I once had my low end a bit lean, and it flamed out just like you describe.. I was high enuff to glide in to a landing.

things to look at;

1) Needles... factory setting plus an RCH lean on the low end is prolly good.
2) Fuel tank/System. No air leaks in lines & a clunk that is functioning correctly.
a) Even a small hole on the clunk line inside the tank can cause problems.
3) Plug wire is secure and not "Floppy, Intermittant"
4) battery... regulated Li-Ion or like a 5 cell NiHm?
5) Ignition module? Verify it is good! Sometimes they run OK for 5 minutes and then quit. (Though I have not heard of this with DA Ign's..still something to consider)
6) Adequate cooling? (DA's will usually let you know they are hot by sagging)
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Old 09-15-2008, 09:29 PM
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Re: DA 50 engine decides to take a break while I'm flying!

No I haven't figured out the cause yet. I put a new plug in the engine because the other one looked like it could've been slightly fouled or getting to look like it was a bit rich. Not really bad looking. Do you always set the gap on the NGK plugs or are they set from the factory? I'm hoping they're good to go out of the box, one less thing to mess with. I'm going to take the needles out, check to see if they're gunk free and retune the engine before flying it again. I checked the ignition leads and they're good. I'm using a 4.8v nimh pack. All fuel lines going to engine from tank are good. I will have to check the clunk line though.

Other than that, the day I went flying I switched from Amsoil Sabre 80:1 back down to 50:1. I retuned slightly, but didn't have a tach with a good battery so couldn't do a full tune. It ran great for a three full flights and than trouble so I don't think my tuning by ear was too far off, I don't know. I hope all goes well this time!
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Old 09-17-2008, 11:55 AM
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Re: DA 50 engine decides to take a break while I'm flying!

I have a 42% TOCXtreme Extra 260 and on the 2nd flight I put on it, I did a low pass right to left into the wind and I pulled my upline and the DA-150 on the front fell asleep. I had to whip it around and fly down the runway, overshoot it, and land in the field. The plane is OK and it still flies, but my problem was the regulators. We replaced those and it flies fine now.
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Old 10-06-2008, 05:47 PM
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Re: DA 50 engine decides to take a break while I'm flying!

Good thing you didn't lose the plane. Mine is now back in the air!!! I have about 8 flights on it since repair and it's been flying great. The plywood I used for the repairs was a little heavier and I added a TBM SB Pitts muffler that's a bit heavier than the stock DA I had on her. Even with the extra weight, I can't really tell a difference. Pull outs from hovers are still good which was my biggest concern besides the wing loading. It's great to be back in the air.
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Old 10-19-2008, 01:36 PM
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Re: DA 50 engine decides to take a break while I'm flying!

15 flights now and it's about back to where it was minus the torn out LG plate. Yes she went down again, this time most likely due to the balsa box mod I did. Read about that in the "Gas Engines" section. Here's the details.

I used Valvoline 2 cycle oil at 32:1 and the engine stayed nice and cool during ground testing. My high end was 1 7/8 and low was about 1 1/4. People have been saying my low is too lean. I tried the DA settings and I was getting smoke from the exhaust and too much of a poor stumbling idle. At 1 1/4 it was just past rich and I had a perfect transition. It seemed to transition faster than it did with the Amsoil at 100:1 and it seemed to have a better pull to it. My plane seemed to vibrate a bit less too. I ran about half a tank on the ground adjusting it and taxiing around. Than I filled up and took off. She pulled vertical and seemed to accelerate a bit faster, which helps confirm my ground pull test. I have no fish scale so I just hold by hand and check. Yes, I've heard that fish scales aren't perfect either. Anyway, I go to idle and pull a snap roll and than nose over to find out that I have a dead stick. I circled around, but it was a bit windy and I got blown past the runway back into the tall grass. I set it down as slow as I could and off goes the gear. Sweet I said, atleast those nylon bolts I used after the repair from last time did their job. I wondered if they would, but really didn't want to test it. I've been flying for about 9 yrs. so I know how to judge the amount of damage by what kind of sound it makes going down and how loud it is. This is a skill gained quite often before one even solos! The sound that she made wasn't a good one and I was hoping it was only the gear. The sound was a bit loud and had the balsa ring to her and sure enough my firewall is ripped out again. Dang it, I'm about ready to lay this one to rest, but knowing me it'll be repaired again.

I think my balsa box flexed while snapping and killed the engine. In the future, any balsa boxes I do will have no flex to them and may be made of ply.

Damage this time:
  • Cowl is cracked by cheek majorly
  • Prop didn't survive this wreck, but it's not totally broken so it can be a wall piece
  • Motor box is shot
  • Front former is shot
  • One wing has another dent from wheel pants and the other has a 3" hole in the sheeting
  • Broken stringer
On the plus side, my exhaust survived this time and my LG plate is in one piece. I just need to make a former, motor box, beef up a stringer, and patch the wing. I've got a spare cowl, but will likely fix my old one until I'm 100% sure that all bugs are worked out of engine. What sucks is that I need to pull out my wing tube again and will most likely damage the fiberglass outer tubing. For the first repair, I cut pieces from the center section and had two short outer tubes instead of one. Why does everyone use one outer tube? For alignment purposes? I doubt a flimsy tube adds much strength so I'd rather not have one. Anyone know where I can get a replacement tube? I've looked around for a paper towel tube or an old model rocket that'd work but had no luck.

I'm sending the engine back in and I'm going to start working on my Raptor 50 getting that back in the air. I'm hoping if there is something wrong DA will find it. I'm going to send in every ignition component except the battery as I doubt it's the battery.

It's going to be tough though to go for a while without hearing that gasser sound or feeling the precision of the 260. It flies great, but I don't think there's enough wood to hold up to a rough landing. My landing must have been rough though to pull out a motor box. I just feel Aeroworks for an example builds them beefier, but than you get something heavier. My deadstick wasn't too much different than I've done with glow planes of .60 size. I guess when you get up to 50cc and bigger, the impact is much more with the extra weight.
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