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DA 50 bog at high G's

Old 06-15-2007, 11:53 PM
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Holton50
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Default DA 50 bog at high G's

well the title says it all.. the DA 50 barley holds onto life in a down line w/ a snap roll. i posted something about this issue a long time ago, an have never done anything about it but fly my extra like a trainer [sm=thumbs_down.gif]............ some guy offered his product.. a crab plate...? http://rcblimpproductions.com/index_files/CarbPlate.htm, i don't know if heas just trying to get my money... or if it really works. anyone have luck with these carb plates?? dose it sound like it would work for my application. if it helps at all the da 50 is in a great planes wagstaff
Thanks
Chris--
Old 06-15-2007, 11:57 PM
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krayzc-RCU
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Default RE: DA 50 bog at high G's

what airframe do u have the motor on?
Old 06-16-2007, 12:01 AM
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Holton50
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Default RE: DA 50 bog at high G's

well hey same person lol... its on the Great planes patty wagstaff
Old 06-16-2007, 12:13 AM
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Default RE: DA 50 bog at high G's

seems at though u and I r working on birds lol

the carb plates do work on some applications you can make some to shied the air from the diaphram its just a square that doesn't let air directly hit that hole. put 4 small washer under the bolts and put a plate over the hole or take an exopy inside plug the red or black plug and silicon it over the hole and then add an 1/8" hole on the side of that plug. if it works you knows its an air issue. if it does not work remove and and no $ has been spent.
Old 06-16-2007, 12:36 AM
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Holton50
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Default RE: DA 50 bog at high G's

yeah, idk dose it seem like my problem is air being shoved down the carbs throat in snap rolls? the engine will run strong at any other point in flight.. inverted, torque rolls knife edges.. its just during high g's. i can only get about a rotation of a snap then i have to bail cause the engine comes to a halt.
Old 06-16-2007, 12:40 AM
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Default RE: DA 50 bog at high G's

do u set a high idle while flying?
Old 06-16-2007, 12:55 AM
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Holton50
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Default RE: DA 50 bog at high G's

no, i set the high/low as per the instructions and the engine runs phonemonal (the break in specs, only have 9 flights on it) with the exception at idle.... when it idels for around a min or so (on ground) then ill jump on the throttle to wide open it loads up a bit but i think thats just common physics at work. Up to say 45 ish sec of idel it will transition great to WOT. think thats within reason?
Old 06-16-2007, 12:56 AM
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Holton50
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Default RE: DA 50 bog at high G's

ohhh ops, thought you said high nedle valve........ but yeah i set a high idle right after take off..
Old 06-16-2007, 08:49 AM
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Default RE: DA 50 bog at high G's

def try the home made cover over the d. hole and keep me posted of the results.
Old 06-16-2007, 09:34 AM
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Default RE: DA 50 bog at high G's

I've done all kinds of things to mine and its better now. I set the pop off presure to 14psi. I added another pulse line to the oposite side of the reed block. And I put a hose on the diaphram cover vent line and ran it inside the fuse. The engine is also broke in now. I've ran 4 or 5 gallons of fuel through it while I was tinkering on it. I still get a little burble when doing rolling circles at just above idle, but I can live with that. Barry also told me to richen my low end and lean my high end and that realy helped with transition. My low speed needle is open 1 and a half turns. Not sure about the high, but I leaned it to run abnout 7350 rpm on the ground with a 22X8 prop.
Old 06-16-2007, 10:19 AM
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Default RE: DA 50 bog at high G's

I would check fuel lines, filters, screen inside the carb and
the needles, the engine should not load, as you state, at any time when you move
the throttle
Old 06-16-2007, 06:28 PM
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Holton50
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Default RE: DA 50 bog at high G's

Steve what exactly is the "pop off pressure" kinda lost on that and the pulse line. how do you make this mods? what dose it do raising the pop off pressure to 14 psi?...and another pulse line? i bough my DA a while back, like 2003 ish so i don't think it has the "update" on it.. dose anyone know what that update fixed? and would it help my application of my engine dieing on downline snap rolls... FYI* the engine runs great at any other part of the flight, inverted, knife edge whatever...
thanks for the input
Chris-
Old 06-16-2007, 10:36 PM
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Default RE: DA 50 bog at high G's

A few DA 50's have these problems. Mine did the same thing. Other people don't have the problem. I finally got a two ZDZ 50 NG's. Problems are all gone, but starting is tricky. I'll take problems on the ground any time over in the air.
Old 06-17-2007, 09:12 AM
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Default RE: DA 50 bog at high G's

Sent my DA in for the upgrades a couple of years ago. I have never experienced any problems with this engine either in the air or on the ground. And its easy to start. I havent touched the needles since the initial set up. Never really found a need to as it has always idled well, transitioned well, and had a good top end. I think sometimes we mess with the needles more than we need to, especially before the engine is well broken in.

A couple of friends have ZDZ's and to say that starting is tricky is an understatement. They do run very well once started and in the air but can be a real pain to start. The other day I had my first flight in before one of them got his to run.
Old 06-17-2007, 09:18 AM
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Default RE: DA 50 bog at high G's

Holton,
The pop off presure on mine was at about 24 psi when new. There is a spring under the "float needle" arm (I think that is what it is called, though these engines don't have a float) that I cut some length off of so the carb pump works easier and delivers fuel sooner. I learned this trick on a carb site for aircraft engines. I think it boosted my thrust from about 23 lbs, to 25 lbs on the ground. It also made my midrange transition quicker. I'll try and post some photos today or tomorrow on the mods. If you look at the carb you will notice a cover with a small hole in it on the raised portion. I soldered that hole closed, redrilled a new one in the center of the raised area and screwed in a hose nipple. then I just atached a piece of tubing and ran it inside the fuse. I brought the post forward for "DA 50 fades with outside manuvers" for you. Some of the mods are posted there.
Old 06-17-2007, 07:43 PM
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Default RE: DA 50 bog at high G's


ORIGINAL: vanguard


A couple of friends have ZDZ's and to say that starting is tricky is an understatement. They do run very well once started and in the air but can be a real pain to start. The other day I had my first flight in before one of them got his to run.
You have to know the trick...I figured mine out. It's now just as easy to start as my DA50.
Old 06-18-2007, 07:28 AM
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Default RE: DA 50 bog at high G's

You have to know the trick...I figured mine out. It's now just as easy to start as my DA50.
And would you like to share, please?

Magne
Old 06-18-2007, 09:13 AM
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Default RE: DA 50 bog at high G's

steve, can you please explain how soldering a new hole in the center of the carb cover would help?

i've been having a problem on my brillelli 46 that sounds very much like what these da's are experiencing. my brillelli uses the same carb (walbro wt201).

i've been having lots of problems with it running very different in the air than on the ground and have done some things that have improved things a lot. however, now the engine would ALWAYS quit in a hover or harrier. it seems like it has a difficult time drawing fuel at the lower rpms. if it's in a vertical attitude or inverted AND at low throttle, it'll almost immediately quit.

anyway, please explain to me how a center hole in the carb cover is better than the hole in the original location.

thanks!

brian
Old 06-18-2007, 11:45 AM
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Default RE: DA 50 bog at high G's

Brian,
On the DA 50's the hole on the carb plate is right on the bend of the raised portion of the plate. I soldered that closed so I could redrill the hole in the center of the raised portion to have a nice flat spot to drill and mount the nipple. Here are a couple photos. The first one is of the stock location and the next of where it is now. The second photo is of my Taurus carb. The DA is in the same place now.
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Old 06-18-2007, 12:15 PM
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Default RE: DA 50 bog at high G's

ORIGINAL: Magne

You have to know the trick...I figured mine out. It's now just as easy to start as my DA50.
And would you like to share, please?

Magne
The same procedure that ZDZ recommends but modified. I prime with 10 flips not 5, when I go to start the engine I always use 80-90% choke.

1) Prime 10 flips, WOT, full choke, igniton off.
2) Flip 5 times, WOT, no choke, ignition off.
3) High idle, 80-90 choke, ignition on. Usually starts right up.
4) After it runs a few seconds, turn off choke, then throttle up with quick bursts and after it warms up it's good to fly.

It simply will not start and keep runing without the choke set at 80-90% (meaning choke is open only 10-20%).

Another trick is that if the engine does not want to fire because the fuel has still not gotten to the carb etc., I go to WOT, full choke, with ignition on. I wait for it to pop a la DA method. After that I go to step 3) above. It always starts.
Old 06-18-2007, 04:22 PM
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Holton50
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Default RE: DA 50 bog at high G's

yeah i think my first step is im going to send my engine to da... after all the problems im having are the problems that the updates fix. ie... engine pretty much quits when i touch down for landing. dose anyone really know what updates they do exactly??? i think i heard something about the carb being flipped a 180. if thats the case, dose that mean i have to re engineer my throttle cause it would be on the other side of the carb now??
Old 06-18-2007, 08:59 PM
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Default RE: DA 50 bog at high G's

hi steve. i understand exactly what you did. i have the same carb.

but my question is how will this improve things?

in other words, why would the position of the static nipple cause the engine to run any better when the nipple is in the middle of the carb plate vs. towards the edge?

thanks.
Old 06-18-2007, 09:21 PM
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Steve
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Default RE: DA 50 bog at high G's

I don't believe it makes a differance where it is, you just have to make sure it doesn't interfeir with the diaphram. That could be a problem if you leave it on the side. I alway dremal the threads off flush with the inside surface of the plate.
Old 06-19-2007, 12:39 AM
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Default RE: DA 50 bog at high G's

oh, i see. it's in the center of the cover just b/c it's easiest to put it there. i thought you put it there intentionally b/c it was supposed to somehow function better.....

thanks for the clarification.
Old 06-19-2007, 08:46 AM
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Default RE: DA 50 bog at high G's


ORIGINAL: Holton50

yeah i think my first step is im going to send my engine to da... after all the problems im having are the problems that the updates fix. ie... engine pretty much quits when i touch down for landing. dose anyone really know what updates they do exactly??? i think i heard something about the carb being flipped a 180. if thats the case, dose that mean i have to re engineer my throttle cause it would be on the other side of the carb now??
They moved the pulse pickup location. It fixes your problem but some think that it causes another problem (engine quitting while inverted at low RPM'S). I think the carb can be mounted either way, just the location of the pulse barb on the carb block changes.

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