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Building a Dynaflite Super Decathlon

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Building a Dynaflite Super Decathlon

Old 06-19-2013, 05:52 PM
  #1851  
WILDCRASHWILLY
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Default RE: Building a Dynaflite Super Decathlon

Well Guys

I tried to maiden today. I worked my butt off but cannot get the engine to run more than 20 seconds and it only did this intermittently. Most of the time it wouldnt even fire. I'm going to check the fuel system starting at the clunk up to and including the carb. Had issues at first fire back in the winter however, I thought I had it worked out. Apparently I was mistaken. Brand new engine very frustrating. I'll also check the ignition but I think it may be okay since it'll fire off. Acting very strange. When it does start it takes a lot of flipping. ZDZ 40. I have other ZDZs and they can be temperamental but this one is terrible. I'll focus on it tomorrow. Maybe I can get it worked and try again Friday.




Old 06-19-2013, 06:43 PM
  #1852  
nh4clo4
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Default RE: Building a Dynaflite Super Decathlon

Good luck, hope you find the gremlin

Keep us posted
Ed
Old 07-05-2013, 05:20 PM
  #1853  
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Default RE: Building a Dynaflite Super Decathlon

Well Guys,

I have tried numerous times to get this engine running the last couple of weeks with no success. I have never seen or had an engine I couldn't make run... until now. I checked the metering lever, the diaphragm, the fuel pump check valves. The ignition performance and timing. When I can get it to start it is very strong now that I adjusted the metering lever to a slightly richer setting. Unfortunately, if it dies or I shut it off, I could flip it a 100 times and it may not fire. I even took the fuel tank back out of it and soldered barbs on the brass in the tank to lock the fuel line tightly at the connections. I have fought this engine longer than I should have. I'm gonna call TBM and ship to them for inspection. Its still under warranty obviously since it has never been off the ground or run longer than 5 minutes for that matter. It's a shame my other ZDZ is a great engine. It's a Super 80. This one is a 40. Needless to say I am getting a negative attitude towards this engine. Maybe TBM can resolve the issue for me and I can finally maiden this engine/plane combo. For what ever reason it does not want to draw out of the fuel tank. Virtually impossible to prime.

Wish me luck everybody.
Old 07-05-2013, 05:38 PM
  #1854  
Bluelt
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Default RE: Building a Dynaflite Super Decathlon

I had the same symptoms on  a 20cc gasser.  Turned out a faulty "opto kill".  LED light was on but checking voltage output to ignition showed intermittent..
Old 07-05-2013, 05:49 PM
  #1855  
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Default RE: Building a Dynaflite Super Decathlon

Thanks blueit.
I dont have opti kill on this one as I have a choke servo set up on my failsafe for secondary shut down. That doesnt rule out my ignition switch though so I'll double check it. However, I did remove the plug and wiggled the output shaft back and forth repeatedly for a minute or so at a rapid motion and the ignition fired every time. What puzzles me is that it doesn't seem to be drawing fuel out of the tank with the choke on full.

Again thanks for your suggestion. This thing seems to defy logic. It's probably something stupid that I'm missing. I had a long time ZDZ user inspect it and like me, he is scratching his head.

Bare with me on some grammer and spelling as I'm on a kindle fire tonight and you may see where I am having to go back and edit my posts. Usually a skipped space or punctuation or something like that.

Old 07-05-2013, 05:56 PM
  #1856  
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Default RE: Building a Dynaflite Super Decathlon

I even took a break from this thing and went over to the profile forum for a week and did a build on a Pro X which is a little unusual for.me as I don't do many ARFs. It went okay and gave me a break from this one but now I'm in the mood to see my Decath fly.
Old 07-05-2013, 05:58 PM
  #1857  
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Default RE: Building a Dynaflite Super Decathlon

Sorry to hear that, hope you get it figured out. Nothing more frustrating than a delayed maiden. Keep us up to date.
Ed
Old 07-05-2013, 06:01 PM
  #1858  
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Default RE: Building a Dynaflite Super Decathlon

Thanks Ed

Didn't want you guys to think I bailed on it. Just having these issues to deal with. The upside is I'll be that much more excited to see it fly.
Old 07-09-2013, 07:20 PM
  #1859  
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Default RE: Building a Dynaflite Super Decathlon

It has been a while but I am almost ready for the maiden flight. 16 pounds worth plane.
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Old 07-10-2013, 04:30 AM
  #1860  
nh4clo4
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Default RE: Building a Dynaflite Super Decathlon

That looks really good! At 16 should be a great flier.
Good luck.
Ed
Old 07-10-2013, 08:14 AM
  #1861  
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Default RE: Building a Dynaflite Super Decathlon

Thank you. I need to put the screws in the cowl, move one of batteries forward and make an instrument panel for a finishing touch. The balance is just slightly aft at the moment. I am happy with 16 pounds for this airplane.
Old 07-10-2013, 02:23 PM
  #1862  
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Default RE: Building a Dynaflite Super Decathlon

Futabaflyer,

Your Decath looks good looking forward to your flight report... Great Job!

I've called TBM twice this week to attempting to talk with someone about my engine. Left a message with someone named Bill Monday as the tech assist guy was gone. Did not get a return call so I tried them again today. Had to leave a message on a thier voice mail earlier today. Unfortunately still have not had a return call and they are closed as of 20 minutes ago. They must really be busy. Maybe I'll hear something from them in the morning. Hope so as I really want to get this thing resolved.
Old 07-10-2013, 05:34 PM
  #1863  
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Default RE: Building a Dynaflite Super Decathlon

Willy,

Sounds like your problem, Ran on the bench, not in the plane.


ED
Old 07-10-2013, 07:06 PM
  #1864  
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Thanks Ed,

I'll go read it.

Old 08-18-2013, 09:09 AM
  #1865  
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Back on the Decath again.
Tried TBM numerous times for tech assist. Apparently customer service no longer applies to them as I have called four times and either left a message on voice mail or was told their tech asst. Guy was out and they would call me back. Never got return calls. In fact their is a thread on RCU about their terrible service. I bought this engine from them but no more. Learned my lesson.
Anyway, I found out about Dons Hobby shop from an advertisement in Model Aviation. I called him to order some metal machine tees they advertised and like the way he treated me. He offered numerous suggestions to my delima.
I would like to know what you guys think about the following.
I plan to convert the tank from a three line where I had a vent, a fill, and a carb line run separate. My carb line is about 20 inches long. Here is the change I'm planning. Go to a two line system. Put a tee in thr carb line about three inches from the carb and connect my fill line here rather than having a separate fill line at the tank. This will cause my carb line to be preloaded with fuel as my issue is fuel pick up anyway. Also, I purchased a metal Perry pump check valve, "rated for gas", from Tower. I plan to install this between the tee and the carb. Hopefully this will keep the gas from flowing back to the fuel tank when the engine is not running. And last, I think I can shorten the line overall by 2 or 3 inches to the carb without having to move tank. Has anyone else tried the chk valve approach on gas? I never have but I've been lucky I guess and haven't had a fuel draw issue until now. I think this valve might restrict the flow on a larger 80 or 100 cc engine but, I may be okay on this 40 cc.

Thanks for any suggestions you have given me to this point or any you add later.

Last edited by WILDCRASHWILLY; 08-18-2013 at 09:32 AM. Reason: spelling
Old 08-18-2013, 12:13 PM
  #1866  
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You will really enjoy the way it flys once you get your engine sorted out. That 40 should be plenty of power. For anyone starting to build one of these I would recommend moving the servos up front and use some carbon fiber rods running to the back of the plane for the elevator and rudder. I might even do this over the winter. I have a pte 36 size engine in mine and had to put a good pound on weight straped to the bottom of the engine to balance it out. A buddy of mine who use to fly pattern for years flew mine the other day and fell in love with it. Said it was one of the nicest flying planes he has flown it quite some time.
Jeff
Old 08-25-2013, 08:34 PM
  #1867  
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Well guys,

As I mentioned earlier, I changed the fuel system over to a two line system. I did away with the seperate fill line and placed a tee about 3 or 4 inches from the carb. I then installed a Perry metal check valve between the tee and the carb. This allows me to fill the tank without intefering with the chk valve. Sounded like a good idea but,,, It didn't work. I have fuel all the way up to the carb now however, it just runs in to a road block and does not get to the engine. This Carb is a WT with two different numbers on it. One is 919 and the other is 201B. since I can't find any listing for a WT 919, I'm gonna assume its a WT 201 B. I'm on vacation this week and plan to fly quite a bit but I'm also, going to run by a small engine shop and see about getting either a replacement carb or at least a carb rebuild kit. I'm thinking a carb though since I've had this one apart and can't see anything wrong with the gaskets, pump, or diaphram. I'm wondering if there is something going on in the casting. I think the metering needle is stuck down. It was the first time I took the carb apart and I freed it. This is a brand new engine which makes it that much more difficult to diagnos as it has never run more than a Tea cup of fuel through it. Here is a picture of the valve and tee that I installed. I got the chk valve from Tower Hobbies and the metal tee from Don's Hobby shop out of Kansas.
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Old 08-26-2013, 04:54 AM
  #1868  
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A 20" feed line does sound to be a bit long. I can't imagine where your tank is for it to be that length on this plane.

My tank sat just behind the firewall on a slide in tray so the feed was very short. I've used a Super Tigre 2500 and a Super Tigre 3000 both running on glow in my Dynaflite Super Decathlon.

On all my gasolinge powered planes, I keep the feed as short as possible, even thoutgh they use pumper carbs. A pump will still not be suitable with a line which is too long. There are only two lines on the tanks - one is feed/fill with a T connection and the other is vent, wrapped over the tank in the standard fashion to prevent siphoning of fuel.

Could it be that you have a problem with your vent line, thereby creating a vacuum? You could try pumping all that you want in that case to no avail.

As for the pleasure of flying this plane and how it handles, why not wait until you try it and then you be the judge if it suits your likes as opposed to others' opinions on it?
Old 08-26-2013, 07:09 AM
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Thanks for the input do335a,

I shortened my carb line during the change over but, it's still probably 16 inches long total length. Like you, I also thought about a plugged vent line. I checked it and it flowed freely. The tank is sitting on the CG under the wing instead of up frontvwhere the plans call for it. When I first got my new plumbing configuration done yesterday with the chk valve. It easily picked fuel up and got it to the carb now which it wouldn't do before. The engine popped once and only once,,, then nothing. I think a very small shot of gas entered the engine. After that nothing. And although fuel is up to the carburetor, none seems to get through the carb in to the engine. It's as dry as popcorn fart.

Last edited by WILDCRASHWILLY; 08-26-2013 at 09:30 AM.
Old 08-28-2013, 06:02 AM
  #1870  
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I am kindof getting in on the tail end of your problem but have you pulled your plug and pour a small amount of fuel right into the cylinder and try it that way? I have had to do this before and it has always seemed to work. It will almost always fire and most times will draw enough fuel to stay running. I have also squirted fuel directly into the throat of the carb with decent results. If it doesnt fire with these methods I would have to look at the ign.
Jeff
Old 08-28-2013, 06:41 AM
  #1871  
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Jeff,

Thank you for the suggestion. Haven't poured fuel directly in to the cylinder but have put a shot through the carburetor, which on this plane and engine config is difficult. It will fire and tick over a few times until the fuel is gone. I have even had it run for about five minutes but when I shut it off, the next time you can flip a 100 times but it wont fire. Pulled the plug and continually rocked the crank back and forth accross the pick up magnet at a rapid pace. Ig. fired everytime. Like I mentioned now thatI have fuel to the carb. None seems to be getting in the engine at all. For instance, yesterday I was flying my Edge which has a ZDZ Super 80. First time started this year. Once fuel got to the carburator, the choke pulled it right into the engine. It likes to start wet. It backfired out the exhaust a few times with a little ball of fire as it cleared it's throat and roared to life. On the Decath with the 40 ZDZ, you can't even smell any fuel, even if you take a sniff at the exhaus stacks.

Good suggestion though thanks for careing enough to respond.
Old 08-28-2013, 07:19 AM
  #1872  
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How about your needle settings? I fought getting my gasser heli started for the first time. It was set at 1 1/2 on both needles. I leaned out the low end and it started. Have you also posted in the gas engine forums?
Jeff
Old 08-30-2013, 05:49 PM
  #1873  
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Jeff,

I initailly set the low at 1 and the high at 1 & 1/2 by the book. Other than a pop after 100 flips,,, nothing. So then I set both at two turns each and got it stated. Only had half throttle at wide open. Shut down and raised the metering valve. Then had to deal with it's inability to draw again. Used a electric starter and after spining for 35 or 40 seconds it started. Was able to get the needles adjusted and shut the engine down after about five minutes to cool down. Engine absolutely refuses to prime. Then went to the two line and check valve system mentioned above. Unfortunately, I have not listed it on the engine forum as I thought this was going to be a minor issue when I started dealing with it. I have read the gas forum history on both RCU and FG sites. I found a ZDZ 40 that did the same as mine and PM'd the op but he hasn't responded with what he found. This only happens with the 40. The Super 80 I have starts pretty good using the 551 method.
The first time I pulled the cover off the carb, the metering needle was stuck. I suspect it's stuck again. I bought a new carb kitp for it yesterday and plan to install it eventhough this is a new carb. I'm concerned it may be a casting issue and I need to get a new carb.

Again thank you.

Last edited by WILDCRASHWILLY; 08-30-2013 at 05:52 PM. Reason: spelling
Old 10-05-2013, 08:18 AM
  #1874  
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Just thought I add my SD to this thread, here is my addition. I still have a few/minor fixings to do but for the most part the maiden was good smooth flying ship. Still moving things around and more things to add then it will fly like a champ. I have a video of the maiden flight, the landing..............well I'm blaming the cross wing I hope wildcrashwilly fixes his issues, it is a good flyer. Mine has a ngh 35 under the hood.
Lee
http://youtu.be/AFDQdlZDOMg
Old 10-18-2013, 11:00 AM
  #1875  
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Hi SD owners!
Does somebody tell one actually thing for me? What about the right trust and down trust angles for the engine, are they desighned in the kit or you made them by your own? Thenks!
New fan of Dynaflite SD! :-)

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