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DA50- Anybody Having Trouble?

Old 12-10-2004, 05:10 AM
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RICK9303
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Default RE: DA50- Anybody Having Trouble?

Thanks for the input guys. I feel better about the problem, and have planned to switch to a better prop this winter. I have noticed that the Zinger ran louder than other props I've tried. I have used Menz props in a 3w120 before, with good luck. I guess I was lazy and grabed from what was at my LHS. Was thinking about 22x10 Mejzlik for the DA50. That prop has come up in talk alot.

Rick
Old 12-10-2004, 08:03 AM
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rmh
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Default RE: DA50- Anybody Having Trouble?

I don't think rpm should cause a problem with the 50 -but I have not tried running one fast. (I am setting up a customer's plane at the moment with one).
If the engine is properly setup - having good fuel and cooling,correct timing and not overpropped or overheated, the actual loads on the cranks at higher revs ,are lower .
The "why" , is that the engine has a peak breathing rpm . (carb/ timing/porting etc..)
Once you exceed the peak breathing ability -- the piston pressures become lower--

Bearing loads happen two ways - radial speed and load.

In any bearing catalog, you see ratings expressed this way - you can push one or the other but not both.
If the bearing mount is not solid (metals move) then either load or rpm will kill em.
Look at the Zenoah etc., bearings -these are BIG-compared to our special purpose engines - they are engineered for very high revs and shock loads.
The engines get heavy in the process.
trade offs
Old 12-10-2004, 09:25 AM
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RICK9303
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Default RE: DA50- Anybody Having Trouble?

Dick, Good thought on bearings, something you don't think of. With the new lighter engines you must be more careful that every thing is set right. That's why I won't take chances on oil either, as far as trying to get every last rpm out of high gas to oil ratios. I would rather stay on the conservative side, 50 to 1 max. to keep enough oil on every thing

Rick
Old 12-10-2004, 09:50 AM
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Default RE: DA50- Anybody Having Trouble?

I have 2 DA-150's both running on 100:1 since they were broke in. They have been back for updates to DA and Dave at DA stands behind mixing 100:1 with oils that are made to run that lean. Amzoil being one of them. I beleave people are taking oil designed to run 50:1 and running at 100:1 because they were told it would work. I have alot of gallons through both of mine with no problems. It seems to me the problem with the DA-50 has been discovered that the rod was not good enough the first time around. If DA is fixing this problem under warranty they understand there is a problem with the design and i'm sure they will do everything to fix it.
Old 12-10-2004, 12:22 PM
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famousdave
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Default RE: DA50- Anybody Having Trouble?

ORIGINAL: Bass1

Desertpig, This is off topic but who is Mark Levinson? Never heard of his amplifiers.

Hi Bass1 .. check out the link here... www.marklevinson.com

They are the bentley of audio... they cost about the same as one too! Incredible stuff...

The monoblock (i.e. one side of a stereo setup) amps "start" at $20,000 and the preamplifiers are vacuum tube type with as close to 0% distortion as you will ever get - The monoblocks weigh 220 # each!

An "average" ML setup is about $100K... less speakers!

My dream system - Levinson electronics and Martin Logan Statement E2 speakers "when I win Powerball"... !
Of course I'll need a 10,000 SF house to put it all in too!


OK - back to R/C
DP
Old 12-10-2004, 12:36 PM
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MustangFan
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Default RE: DA50- Anybody Having Trouble?

Don't worry about the 22X8 Zinger ... thats not the problem ... I used the same all summer on a Patty Wagstaff.
Was only using 1/2 to 3/4 throttle most of the time ... only full throttle on some vertical maneuvers.
I orginally used it to hasten break-in by getting the RPM up.
Maybe not the best prop ...

I too had to send my engine back after a few gallons, hard to start. (Last Year)
They changed the ignition module, and the mechanicals you mentioned.

Ran all summer without a problem.
When I talked with them (phone), they indicated that a problem showed up with the bearings allowing some fore/aft motion. They were changing other components as a precaution.

I did notice some fore/aft motion of the crank before I sent it back ... but not now.

I ran at least 8 gallons of fuel thru it this summer.

Good luck !
Old 12-10-2004, 03:10 PM
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rmh
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Default RE: DA50- Anybody Having Trouble?

One more thing Rick-- are you under the impression that a richer oil mix will slightly reduce power?
This is an OLD HORSE PUCKY idea.
The 32-1 oil mix is simply avg -used in bikes etc..
thoroughly tested proven in lots of racing venues.
down to 20's-1 is also used.
My own engines never run as fast as they do now .
Old 12-10-2004, 04:34 PM
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Default RE: DA50- Anybody Having Trouble?

My DA is a DA-50-R.. came from the factory a month ago.. I guess they may have put the improved parts in yours.. Cool thing of them to do.. I am sure that increased oil content will decrease your RPM's because Oil is less flamable than Gasoline... I think Thats why many brake them in and then switch to Synthetic 80:1 or 100:1 for more power.. I personally am running about 50/60:1 Amsoil for break-in and I am still on my first gallon.. Some will curse me but oh well it is my engine, it runs fine and I don't want to hear it... I will run a leaner mixture a few gallons down the road...
Old 12-10-2004, 05:49 PM
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Default RE: DA50- Anybody Having Trouble?

Dick's right. More oil = More power, to a point.
Don't ask me that point, I have not done any testing, just read a couple of articles and heard a few old guy's talk.
Old 12-10-2004, 06:35 PM
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Default RE: DA50- Anybody Having Trouble?

you guys have it backwards,lol..more oil normally means less fuel to burn per stroke...the oild does not burn (if some does, it makes no power)...this is more so true with high performance engines...the higher the performance level, the more it holds true....
Old 12-10-2004, 07:36 PM
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Default RE: DA50- Anybody Having Trouble?

CDIGNITION- Not true for 2-strokers. Ask RCIGN, he has done some testing. You have a nice aviator>
Old 12-10-2004, 10:47 PM
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rmh
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Default RE: DA50- Anybody Having Trouble?

The "point" is according the racing bike experts down around 20 -1 .
For those who believe otherwise -- have any of you actually run high performance gas two strokes?
On glow engines the alky/ oil ratio is best at around 20% NOT 20 -1 (6.4%).
50 -1 = under 2 1/2%.
I run 32-1 exclusively on gasoline .
Heat control (friction control ) on pre mix ( also no direct oiling ) is crucial to getting best power on these engines .
Old 12-10-2004, 11:23 PM
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Default RE: DA50- Anybody Having Trouble?

Dick- don't forget better ring sealing with more oil.
Old 12-11-2004, 10:32 AM
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Default RE: DA50- Anybody Having Trouble?

Dick,

How does the Mobile Oil compare to H1R? I can't seem to find Mobil oil ANYWHERE here, but I can get copious amounts of H1R. I plan on running 32:1.
Old 12-11-2004, 10:43 AM
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CDignition
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Default RE: DA50- Anybody Having Trouble?

The Majority of 2 stroke high performance Outboard engine will run an oil injection system...at WOT, making full power, using Synthetics, they will normally run in the 100:1 range...with Dirtbike motors, you do have cooling issues to deal with along with longevity issues, this is more likely the reason for more oil...also, true engine testing across 2 different platforms means nothing (comparing dirtbike motor to a 150 CC airplane engine)....Dirtbikes also utilize expansion chamber technology, which also changes the way the engine works to a large degree..apples to oranges here folks...

One thisg to remember, a motor is just an airpump....simple principal here..the more air/fuel you can inject into the motor on a given stroke, the more power you get...with oil taking up room that fuel should be, power is less...
Old 12-11-2004, 10:55 AM
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rmh
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Default RE: DA50- Anybody Having Trouble?

I don't know -but I would suspect-- that inasmuch as they cater to the same BIG market (not us)- that it is in the same ballpark for specifications and use --like Redline Racing two stroke/ Klotz two stroke etc..
I am completely baffled by all the interest in running oils at extreme low % ratios .
NONE of the high power sports engine stuff especially performance bikes - do this .
We are running such small %'s -relative to the gasoline -that the idea that a bit more oil decreases power , really surprised me .
My testing , running of different oils has shown to me , that the 32-1 mix did two things immediately:
first - the incidence of scratches on the pistons dropped . tho this was never a big deal - it did change.
Next - the incidence of carbon -which was all over the place with non synthetic oil -- vanished.
third - overall performance went up.
I have never had a rod bearing failure in any of my engines (mostly ZDZengines) - so I obviously had mixtures about right all along .
I have scored and ruined a ring and barrel in hot weather running -on an 80 - a couple of years back - using 50 -1 stuff and running a bit lean -obviously -
I will really see how much improvement has occurred by the end of next summer .
I am not a degreed engineer - but have learned that if you don't have any failures - you never really tested anything - so - I will keep adjusting parameters and watching .
SO far so good on this stuff.
Old 12-11-2004, 11:08 AM
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Default RE: DA50- Anybody Having Trouble?

I'll give anyone 5 bucks if they can tell a difference in power while flying between 100:1 Amzoil and 32:1 Mobile. I just want to keep my engine as healthy as possible. If I need more power, I probably have the wrong prop or exhaust.

So... Dick... does H1R prevent carbon as well as Mobile?

Thanks again!
Old 12-11-2004, 12:57 PM
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Default RE: DA50- Anybody Having Trouble?

Ok, I've taken a small engines class and even rebuilt a few granted they were all four stroke engines. We talked about why you mix the gas and oil with two stroke engines but we didn't talk about how the gasil ratio affects performance. Does a ratio of 32:1 provide more performance than say a 50:1 or 100:1? If so, how does that work?
Old 12-11-2004, 05:30 PM
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Default RE: DA50- Anybody Having Trouble?

Ben... that's waht everyone is bickering about about. From what I have read in this forum and the engines forum, Dick is very experienced with airplanes and gas engines and has tried TONS of different combos in AIRPLANES as well as other gas motor applications. That's all I'll say.
Old 12-11-2004, 06:43 PM
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RICK9303
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Default RE: DA50- Anybody Having Trouble?

I do know a while back some one wrote a article on oil ratios, performance, and heat. They started a 20 to 1 and went to 100 to 1, with a bunch of different high grade brands. What he found that that as he leaned the oil ratios some performace was seen, but so was heat. When he got to 100 to 1 he saw no increase in rpm, but did see a noticed increase in temp. His oppinion was after 50 to 1 there was no performance gain. He mentioned that some flyers swore by the 100 to 1 oils, there cleanness and power. One point was brought up about different times when flying were you had little or no forward speed to bring in air to the engine for cooling. This was the time that a richer oil content help protect the motor. IMO use what you have luck with, but if you go to the higher ratios, keep a close eye on engine temps after running.

Now with that said, ALL I asked to start with, was anyone having DA50 engine problems. Not
what prop to use, or oil to use or what ratio, or anything about any other engine. Thankyou to those who responded to my question. It would be better if people would stay on the subject matter, and start your own thread if you have a question not pertaining to what was asked.
Old 12-11-2004, 09:39 PM
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Default RE: DA50- Anybody Having Trouble?

My DA-50-R ran great for the first gallon. Now, half way through the second gallon, it is absolutely impossible to start by hand and has alot less power. I never tached it so I don't know how many rpm's it lost but on my GP Christan Eagle it went from unlimited vertical to very little vertical. I am running a 23x8 Mej. and 32:1 lawnboy ashless. When I called DA (12/10/04)they didn't sound the least bit surprised about this problem and told me to check the timing. If it wasn't correct I should send it back to them so that they could replace the hub. I haven't had a chance to check it yet. Since they were talking about replacing the hub if the timing was off...it sounds to me like they might have a problem with the key-way in the hub being out of tolerance or maybe the key cracking/breaking (but that is just a guess on my part, I'll will post when/if I find what the problem is)
Old 12-12-2004, 12:02 AM
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Default RE: DA50- Anybody Having Trouble?

If you run more oil, it doesn't displace any gasoline. Your engine can only burn the amount of gas that is appropriate for the amount of air (oxygen) in the cylinder. Changing the oil ratio from 1% to 5% will not have a significant effect on the amount of aiflow through the engine. The needle on the carburetor is the only thing that determines how much gasoline gets burned. You want to burn more gas...open the needle. But, you'll make the most power when the air to fuel ratio is around 12:1. The only reason to go to leaner oil ratios is less exhaust smoke, lower air and water pollution. If the water cooled motocrossers and air-cooled kart motors could make just a teensy bit more power running leaner oil ratios, don't you think they would be running 100:1? The factory sponsored racers can afford to throw away engines after every race.
Old 12-12-2004, 08:51 AM
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Default RE: DA50- Anybody Having Trouble?

yep---
Old 12-12-2004, 11:30 AM
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John Murdoch
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Default RE: DA50- Anybody Having Trouble?

Man... I had problems with my 50 on Friday. Last time it ran, ran great. Friday.. Different story. Wouldn't even pop.
Checked Battery
Checked Fuel Flow
Checked Choke
Checked Switch
Removed Spark Plug - Plenty of Fuel - Cleaned out cylinder of all fuel and started over again
Manually Primed

Still nothing. Flip, flip, flip and more flipping. Now my shoulder, which isn't in the best of shape anyway is completely out. I can't lift my arm any more than just hanging straight down.

Next Step.

Remove Engine
Get Box
Place engine in box
Create UPS label to Desert Aircraft
Drop off box at UPS

Next Step
Go to doctor
Get Doctor Bill
Get Envelope
Address envelope to Desert Aircraft
Place Doctor's Bill in envelope
Mail envelope
Old 12-12-2004, 11:38 AM
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sillyness
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Default RE: DA50- Anybody Having Trouble?

Check the wires where they go into the anderson power-pole connector for the ignition. They are brittle and I kept having them break. I got rid of the connector and soldered the wires to the switch.

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