JoeAirPort

My Feedback: (41)

My Elite 1500 NiMh 4-cell measures about 5.5 volts with a 500 ma load on it before the 1st flight. After about the 6th flight it's down to about 5 volts. Just today I put a 1 amp load on it before going home and it was around 4.92 volts. So this battery is perfect for about (6) 10 minute flights. Any more and a full throttle load might pull it down below 4.8V. It's a good pack for my ignitions.

Junaid that pack probably was not the best NiMh cell....or maybe the quality wasn't the best. I have also had packs that didn't seem to hold their voltage. The 2/3A do much better than AA with higher loads. The Elite 1500 is a 2/3A cell. Next year I'll probably go to A123.

Edit: I just re-charged my plane after flying this morning. My rx battery took 1382mah and ignition 491mah. That's 5-6 flights at about 10 minutes each. I have all 7955's.

Tired Old Man

My Feedback: (1)

The kicker is that the better 4.8v ignitions will function properly a little below 4.8v. Some at 3.9v or so and others around 4.3v. A 4.8v nicad will not be harmed going a little below rated voltage. In many cases it's good for the battery to run a bt under to disrupt memories in battery types that develop them. Stopping at rated voltage is just a cut off point used to protect oneself from killing planes by delving too deeply into a flight battery. Ignitions tell you when the battery is low by causing the engine to run rough, and in ppm 72 systems by generating a slight radio glitch with some cap and lead types.

The old Brison 3.2's were run all the time up to 13,000 rpm using a standard CH ignition, so the operating and advance mechanisms in at least their ignitions is not a limiting factor.

Junaid Ali

Ok guys I think I am probably over doing it with ignition batteries and there is a possibility that my NimH pack is not good quality stuff, however i do feel safer with the 2200 maH Lipo. I want you to help me with a small problem that I have with my DL 50. Needles seem to be adjusted properly and the engine runs ok but whenever I bring the throttle back sharply from max to low idle there is momentary dip below the idle RPM, it feels that the engine might quit but it doesnt. The rest is fine but its making me nervous, havnt been able to tune this problem out or is it normal.

Tired Old Man

My Feedback: (1)

Might still need a little needle work Pull the plug and see if it's a little wet.

JoeAirPort

My Feedback: (41)

Mine does that too and I bet it's like TOM says...we probably need to lean our high needles. I know mine is a little too far out at 1 3/4 turns. It doesn't ever quit though...it's just a little concerning to see it do that on the ground. Needles need to be tuned right for these babies to run properly....I'm learning that process myself.

Moki 1.8

My Feedback: (11)

Man tell me about it. Mine runs great on the ground but the minute I get in the air it starts running rough, like its chokeing are something. Its not the engine, its me. This is my first gasser and im still trying to learn how to tune this thing. I think its still to rich, so im gonna try leaning it out some. Wat yall think about that, does that sound like the fix to my problem?

Tired Old Man

My Feedback: (1)

They will be blubbering, starving, or running great. Which it is tells you what it is. Starving is lean, blubbering is rich. Stumbles hard from low to high rpm is the low needle, not the high.

Tired Old Man

My Feedback: (1)

One other thing. They'll be a lot easier to figure out if you don't back off the high needle on the ground. You obtain a true indication that way.

The Big Kahuna

Howdy folks, I recently came accross a fuel additive that has really made a differece to my DL50. A mate introduced me to a Canadian product that goes by the name of "Bi-Tron" It is a petrolium base product which is added to your fuel at a rate of 1 to 2%. It is attracted to all the hot spots in you engine and treats the friction surfaces for better lubrication.
What I have found is as follows:
1.. Rpm increased by 170
2.. Engine temperature dropped by 18C
3.. Quiter running engine
4.. Better fuel efficiency
The Bitron company guarantees it will not harm your engine in any way, on the contrary they claim it will improve the engines life expectancy and performance.
I've been using the stuff for 6 months now and I'm Sold on the product so I now use it in all my vehicles, mowers and gas aircraft engines.
To find out more about this stuff go to [link]http://chorney1954.bitronglobal.biz[/link]

If you hunt around on the site for the Bronze Package, you will be able to buy it at wholesale. It's not expensive but it sure make a difference in my DL50 and all other engines.

RTK

My Feedback: (1)

If it runs fine on the ground and poorly as soon as it hits the air it is probably an air pressure problem acting on the metering diaphragm and in your case a positive pressure causing the richness.

JoeAirPort

My Feedback: (41)

Also you can try a velocity stack. That helped mine a lot.

Moki 1.8

My Feedback: (11)

RTK, what you think I should do? Cut more holes in the cowl? I would really hate to do that, it looks so nice. Any suggestions guys?

JoeAirPort

My Feedback: (41)

1) tap the metering diaphragm vent hole for an 8-32 barb fitting. Plumb vent into fuse.
2) Install a velocity stack.

This made mine much better.

RTK

My Feedback: (1)

Moki,,,I would do as Joe mentioned. First run a line from the diaphragm metering hole to a balsa box, etc. Make sure what ever you attach to the hole does not touch the diaphragm itself

giddyuperic

I would like to know why this is not addressed at the factory. And now don't every body bite my head off. But none of the DA guys do this they just say this is the way the motor is . You should have the low and high neddles set so it only bogs alittle bit on mid range. I would just like to know if they the factory tells people to do this or is this something someone found out that it took care of the problem. I have gone to three or four IMAC events and all of their planes make that sound some where along the power band. Is it more of a adj on the neddles then the tube thing in the carb? Now please don't jump all over me this me asking about this.

mstam1971

My Feedback: (2)

Do what works out best for you. That levering diaphragm is a demand regulator. The diaphragm controls the fuel flow based on the suction of the engine. Because the diaphragm moves up and down, it needs to be vented. If there's an overpressure on the vent hole, the regulator allows more fuel to go to the engine making it run richer. To have your engine running the same in the air (pressure building up in the cowling) as on the ground, you want the vent hole to 'see' the same pressure. To achieve this, put some nipple and small Tygon tubing on the vent hole going inside your fuse. Inside the fuse you can eg use a film container. For best results, put something like a condom in the container and pinch a super tiny hole in it w/ a needle. Put a nipple on the lid, punch a tiny hole in the container, close lid, remove excess condom, connect vent line (Tygon tubing). With properly adjusted needles, this solution will give you a super smooth transitions w/o any burbles.

giddyuperic

I was just asking why this seems to come up and the factory as not taken care of it> That all I found some other fixs too on TBM web site. It seems from the photo that it is just a plate blocking the flow of air in front of the carb so there is a nice low air presure behind it. I have yet to run it to this problem so I am just asking around. I understand it and see what the fix is. But if I do then I will know how to fix it from all the info I have got from this great thread.

liquid_TR

If the engine runs as nicely in the air as it does on the ground then there is no need to put a nipple on the regulator cover and run a tube thru fuse. If it does seem run rich in the air, check the midrange on the ground again, before putting a nipple on the reg cover. It is usually not leaned out enough on the ground. If its adjusted properly and still goes rich in the air, it calls for a fix by putting a nipple on the cover and tube into the fuse. But this is not classified as an "issue" with the engine.

Adjust for maximum rpm on the ground, dont richen back 100-150 rpm on the ground as with glow engines.

Never trust factory settings. Just re-adjust to 1.5 turns out on both needles before ever starting break-in.. and properly lean both needles after first tank of fuel.
These are pretty basic engines, and they need proper carburation for best performance.
DL50 should idle at 1200-1300 RPM reliably all day long on a 23x8 Xoar - JXF or mejzlik and throttle up without coughing.

arobatx

Edited....posted in wrong thread, sorry guys!

[email protected]

Mine stil on the ground for an other hour break-in. If i want lean (high or low), i turn out or in ?

Super08

My Feedback: (2)

To lean turn it in. The high speed needle is the one farthest away from the engine and the idle is the one closest to the engine.

Tired Old Man

My Feedback: (1)

giddyup,

The reason is that with the DA 50 the problem has nothing to do with a diaphragm. Or at least rarely.

On other engines carb location, orientation of the diaphragm plate, cowl inlet shape, and a few other factors influence whether or not a model will experience diaphragm pressure problems. Only one of the numerous planes I've had have experienced the problem with several engine types and sizes. That one was resolved withj a simple deflector to divert impact air away from the diaphragm cover plate So it's not possible for a manufacturer to pre-determine if one person or another will have a problem. They also have to deal with individual installation and engine set up problems that are entirely the fault of the end user. Most problems are found in that group. A very large percentage of the time a new gas users new engine problem will be a lack of basic carb tuning or improper installation and set up.

Super08

My Feedback: (2)

Pat I ran into the diaphragm problem for the first time on one of my engines mounted on a PT-17. It was so bad it would go pig rich as soon as I put the cowl on and restarted it on the ground after tuning it with the cowl off. Didn't even have to get it in the air. It was on a piston port engine though which IMHO are more sensitive to the problem. It was interesting to see what actually happens instead of just reading about it. It was a good learning experience.

JoeAirPort

My Feedback: (41)

I'm seeing a few problems discussed here: Needles not tuned correctly, engines with fat mid ranges that can't be tuned out, and air instability in the cowling. The tuning of needles is the easy one. The fat mid ranges you just live with. The air instability can be resolved by plumbing the metering diaphragm vent into a more stable area....take your pick where. I like the fuse. And the the air instability affecting the air inlet of the carb can be resolved with a velocity stack. I agree that the engine mfg's can't design an engine that is immune from all these problems (and still be light, powerful, and cheap). We have to resolve them according to our own air frames. I used to like to blame DA but experience has shown me to do otherwise.

giddyuperic

Thank you very much and I understand it very well now. Thanks