Hi Guys:

Been fighthing my DA50 in my Aerotech Yak all summer. Been very tentative on the needles, as I'm somewhat new to gas, and have been told SMALL adjustments. My problem is my engine would run fine on the ground in every attitude, but in the air, as soon as I got in an extended upline or inverted, or any extended snap maneauvers, the engine would loose power and threaten to cut.

I tried the "balsa box" solution from the Carb vent. No change. I finally turned the Low needle about a 1/8 turn richer, and now it seems to be doing much better. It will still start to loose RPM in a long upline if I'm below half throttle, but I can fly inverted and knife edge almost indefinately. I'm at the point where its starting to not transition as quickly to the high end. I'd like to resolve the power loss on the uplines and in snaps. How far can I push the low needle before I have other problems?

Also, this engine vibrates pretty badly. On my glow engines, I always mount my props in line with the cylinder at full compression, and this seemed to help with vibrations. I wanted to do this with the DA, but others have told me to mount it horizontal on compression to keep the prop. from stopping in a bad position on a dead stick. It would seem to me to be better to reduce vibrations MOST of the time, then to worry about the dead stick that MIGHT happen. Will aligning the prop and cylinder make much difference with vibrations on these engines?

Thanks!

Lee

Lee,

if a gas engine looses power on the uplines then the high end needle is too lean. Go back to the factory settings and try this:

From the factory setting leave the high speed needle alone, lean the low end needle until the engine will no longer transition, then richen it back up about 1/8th turn. Now check your rpm at full power. LEan the engine until you get max rpm, then richen back up until you lose about 200 rpm

Now go fly.

Also vibration can be caused by a bad engine setup or an out of balance prop. It's very important to blance the blades and the hub. The DOD web site has some great videos on how to do this.

http://www.downonthedeck.com/videos_instruction.htm

Clikcon the video for prop balancing

Aslo what prop are you using, Too much prop can cause an engine to overheat and run lean

i agree with bubblegates

plus how old is your motor as in the manual no extended uplines until run in thats 5 gal and how much airflow is the engine getting

Guys:

It's fine if I'm over half throttle, so I don't think this is a high needle setting. And the Hi is dialed back a bit from peak.

It's got about 3+ gallons through it, so it's still pretty new. I don't push it around that way frequently, because it is new. There's plenty of airflow. The Yak has a large inlet, their is a large cut out in the bottom, and their are holes in the fuse open for the canister muffler. The prop has been balanced carefully. I have a True turn spinner. I've never tried to balance the spinner and hub before.

Regards,
Lee

Lee,

I have a thought here. I'd be happy to come up and fly with ya since we were going to do that anyway a couple of months ago and help you with the engine at the same time. I'm pretty good at setting them up. The earliest I could do this would be Saturday morning unless my daughter makes me a grandfather this week, she's do today

I do need to know the oil mix/type and prop size and brand you are currently using.

Check your PM's I'll send you my number

If the weathers nice and my wife hasn't got me booked, that could work out. I'm using Amzoil 100 to 1 mixed at 90 to 1 (just for a little extra margin). I ran the first three gallons using lawn boy, but that made a big mess. I run a 22 x 8 MSC Prop.

Hope everything with the baby works out. It's almost always exciting. Glad I'm not quite ready for the Grandpa stage yet! ;-)

Regards,
Lee

Lee,

The first issue is the prop. Although it's a 22X8 it's a wide blade so you are lugging the engine down too much and overheating it. Granted MSC makes great props and I am in no way picking on them, but to give you an example:

On my Brison 3.2 (52cc) it turns an MSC 22X8 at 7100, but stick on a PT models CF 22X8 prop or a Mezjlik 22X8 and now it turns it at 7500. The main difference is the blade type. The Da50 is probably turning the MSC at something like 6400 and it should be running around 7000 until it's broken in which is 5 gallons on 32:1 and then 5 more on 100 or 90 to one.

You could order an NX or a 3W 22x8 wood prop from Aircraft international in NJ and get it overnight from the cost of ground shipping for something like 25 bucks. PT models props are 54 bucks from Troybuilt models in Florida

If you hang on until I get there I have a DA50 drilled 22X8 PT models CF prop and I'll show you the difference.

The second problem is the mix. You really need to run 32:1 lawnboy for a minimum of 5 gallons. Yep, it's more mess but only for a little while. While going to 90 or 100 to one early will not really do anything, the engine will take a lot longer to break in.

As far as the grandfather thing, I may be turning mainly gray, I'm still only 46. At least she is 25 so she did not start too early.

Ok now for the main question. What would you like me to bring to fly? I can bring my Yak if I get the smoke installed by this weekend or the Cap or Ultimate, take your pick. At that distance I can only bring one since I'm driving a Ranger shortbed.

Boy, your only two years older then me and a grandpa! God bless you man. My oldest just turned 13, but I have a younger sister in law who just became a grandma. She's only 38, but she started a wee bit too early.

I've had people tell me keep going with the 32:1 and other says switch to the 90:1. I tried to compromise and did 3 gallons with Lawn Boy instead of 5. Interesting notes on the Props. I figured I was going easy on the motor with the 22 inch for break in, and purchased an NSX 23 to move to once it's broken in. That said, with the Yak and my CF landing gear, I'll be staying with a 22, as there is just not enough clearance. It was also my understanding that a wood prop is better then CF as it weighs less, and spools up and down faster. I don't fly fast, so I wanted something with good torque. I would agree that I'm not getting into the power band of the motor with this prop though, so something that spins faster to get a given thrust would probably help in general.

Bring the Yak or the Cap. THe Cap looks pretty sharp. Which model is that? And which Yak? Not Aerotech, I'm sure. ;-)

Have a good one!

Lee

Beleive it or not, the PT models props are right in line with wood props for weight, I think the 22X8 is something like 4 ounces before drilling. I'll bring one for you to try out. At such a low oil ratio at 90 or 100 to one, you definitely do not want to load the engine too much during breakin. Oil is most of the cooling the engine gets.

the Cap is the Great Planes 27% with a DA50 with over 200 flights now and the Yak is the Aeroworks 50cc Quick Build with some custom graphics from BadBradGraphics at right at 100 flights.

I gave the Aerotech one away as I could not stand it. It had way too many issues. If you think back I had given it to whaturi and he tore all the covering off of it, repaired the incidence problems and installed a MVVS58cc and then promptly got it too fast and fluttered it to little bitty pieces.

The Yak is powered by a 3W55i on a header and KS tuned pipe at 18.75lbs minus the smoke system I'm installing. It's got JR8611's everywhere.

Here is what I will bring to help you out with, we may not need them all but ya never know.

PT Models 22X8 predrilled for the DA50
New spark plug
Carb gasket kit
Infrared temp guage
Fuel at 50:1 using Motul 800. This fuel mix leaves not mess at all and keeps the engines at a nice 175 degrees.

I got away from 100:1 for both the Da and 3W engines since I fly mine pretty hard and was seeing temps in the 220 degree ranges with the needles set correctly.

Don't worry, we'll get it running good for you

Yeah, I know you gave your Aerotech away, just wasn't sure what you replaced it with.

Are those the stock graphics on the Cap? What's it weigh in at?

The Aerotech Yak definately has a few issues, but overall, I'm pretty happy with mine, and with the BadBrad graphics, it looks pretty good. I get lots of compliments on it.

I think I'm pretty close on the motor now, but willing to try a few things to get it 100%. If that prop works better, I'll happily switch. No particular allegience there. I have a 24 x 8, but aside from the clearance issues, I think it's just too much prop.

Take care,
Lee

Lee,

The Cap comes in at 13lbs 8 ounces and yep, they are the stock graphics. The thing does a 10 foot takeoff roll at full throttle and goes vertical until I still it to stop. I like Brad's graphics. I had them on the Aeotech and now on this one and orderd a set for the 33% WH Edge I just got. I prolly won't have that one ready for a few more weeks yet.

How did you get the Cap so light? Most of the GP stuff is pretty heavy from my experience?

I had a 33% H9 Cap with a DA100. It flew very well, but tended to snap a little too easily for my flying style. I sold it and have been downsizing the fleet and doing more electrics.

I have an original H9 33% Extra with a Brison 6.4 in it. A bit heavy, but it flies great. Not worth selling as it's too out of fashion now. I bought the Brison well used and have never had to mess with the needles.

I was able to get the DA100 setup pretty well with no problems (it was used and broken in too though).

The DA50 has been a stickler. Maybe it's just not run in enough. Other guys at my field have them and haven't had any problems.

The Cap is mainly stock. The only thing I did not use out of the box was the control rods. Everyhing else is bone stock

I'd be interested in seeing the H9 Extra...I always did like them.

Well, you'll have to see the Extra at my house, as I have the same problem as you. Can only fit one at a time in the back of my truck.

I have a small home made trailer, but it's full of wood pellets at the moment. ;-)