757jonp

My Feedback: (48)

I've got a situation with a DLE20/Mojo 65 combo that's got me a little puzzled, lets chew on this for a while. When I installed this engine on this airframe I reused the 16oz fuel tank previously used with a glow setup. Only change (other than setup for gas) was to move the tank back under the wing near the CG. The thinking was why not, I've got a good fuel pump with the engine, take advantage of it and get your fuel tank placed where regardless of the amount of fuel remaining, the CG will remain where it was to start with. For the most part this has worked well, e x c e p t when the fuel tank is full. With a full load of fuel, the engine will run normally e x c e p t when inverted. Flipping this turkey on it's back with a full tank will result in an immediate stumble from the engine and a possible deadstick unless the revs are kept high, where it will continue to run, but not well. Hard to tell if it's gone lean or rich.

Here's the kicker though... when the fuel level lowers to about 3/4, it runs fine in all attitudes. Hmmmmm? Now, there's no reason to have a 16oz tank on this plane,(other than that's what I had at the time of conversion) so I've run it for quite some time with a partial tank and it'll run without skipping a beat. The only thing a little unusual about my setup is that the tank is mounted about 16 inches back and 3 inches below the crank centerline.

The only thing I can think of that might cause a problem is that when inverted the tank would be 3 inches higher than the centerline and the weight of the fuel may(?) overpower the fuel inlet to the carb pump, and cause the engine to go rich. But that doesn't really explain why it wouldn't happen all the time, not with just a full tank.

Any thoughts?

microdon2

My Feedback: (47)

757 - a thought - maybe you can try moving the tank around so that it doesn't have that inverted height difference, and maybe back closer to the engine. See if that makes a difference.

On my 70" Revolver with and OS 120 4s I have a "T" in the fuling \ carb line. If I don't close the throttle all the way some fuel leaks out of the carb when I fill it. Guess that doesn't happen with gassers cause of the fuel pump membrane.

RiverLarry

R D B get a VENT filter from Dons hobby shop !!!!

thay have a removbl filter you can cleen $ $5.00 R/L

sandyjain

I would definitely be interested in the nos. on a 17x7 and also would like what brand is that prop. never thot they made a 17x7.....

757jonp

My Feedback: (48)

Microdon...

Thanks, but moving the tank would defeat the purpose of putting it on the CG, a desirable place to have it for this type of aircraft.

Ernie Misner

Have you checked out this thread? http://www.rcuniverse.com/forum/m_11352205/tm.htm

mesaflyer

I believe that Microdon2 is suggesting moving the location to rule out that the location is the problem (sorry to speak for you Microdon2). I have a Mojo 40 (fun plane) so I presume that you have the tank below the wing? Try putting it on top of the wing, or vise-verse? If you are dead set with that location, then I would try a smaller tank. My guess is it goes rich when inverted. I have a DLE 20 in GP Extra 300. Has an 8oz tank on the CG and runs for any easy 10-12 minutes, but I don't run full throttle the whole time. Has great transition at any attitude. Plane/engine combo is an absolute blast to fly, but full throttle the whole time is just burning holes in the sky, literally.

757jonp

My Feedback: (48)

Thanks guys for the suggestions and pointing me towards that particular thread. I'm due to bring the airframe in shortly for some work, during which I planed to tear down the engine in inspect the crankpin to see how it's doing after 75 flights since I replaced it (the one that broke looked galled).

I suspect the metering valve is getting overwhemed by fuel getting by the pump valves with a full tank/inverted... A little more spring pressure might do the trick.

Ernie Misner

Hey let us newbies to walbro carbs know how you go about that.

microdon2

My Feedback: (47)

mesaflyer - yes, I was suggesting moving the tank, which would - for the experiment - require some off-setting added aft weight to counter the CG shift. Though trying a smaller tank might do the trick.

RiverLarry

OK Ernie Call me!! P M me your phone ## R/L

1 did you have this truble all the time !!!!

2 does it all ways do it inverted !!!!! only inverted

befor you start tearing thinga apart 1 of you PM me with your phone ### and we can chat I have sean this befor

on a SLAB type plane But now it is fine R/L

Ernie Misner

Thanks River Larry! If you go back a page, it's 757jonp that's having the issue with full tank / inverted tuning issue I think.

Richard D Bahmann aka/Wrongway

My Feedback: (42)

I have a vid loading. The 17x7 needed to be re tuned, I had to rich en up the top end. When all done I saw 8640 after the flight. The little motor is a beast... I thought for sure the JC would load it down more than it 170 rpm.

Richard D Bahmann aka/Wrongway

My Feedback: (42)

http://www.youtube.com/watch?v=rdFTq...ature=youtu.be

armody

My Feedback: (10)

Hello all,.

What is the ideal idle RPM and WOT RPM for DLE20 with 17X6 Xoar Beechwood prop on?

I still haven't gotten to fly my plane since we've lost our flying field. All members are offered to join another club and our club's guys are looking for a new flying field. Yesterday I started my DLE20 again, and WOT RPM was between the range of 8,200 to 8,500. Idle was 1,600 to even 2,000. I ran rich on HSN but since I've been told that due to the DLE's ignition settings it takes 5 to 10 seconds to come down to lower rpm. It also died down on idle, I had to tweak LSN to little lean then it didn't die down. I've followed the instructions, but somehow idle RPM does not seem to be right, at WOT it looks like motor's running OK.

Can anyone please tell me what am I missing here?

P.S. I have changed my tank's setting completely. Using Du-Bro's tygon, T-connector

Du-Bro's In-line fuel filter http://www3.towerhobbies.com/cgi-bin...&I=LXFRL5&P=ML

Du-Bro's tank filter http://www3.towerhobbies.com/cgi-bin...&I=LXD741&P=ML

I'm using Hangar-9's hand fuel pump, and somehow it is not completely sucking out the gas from the tank, I had no choice but to leave little bit of fuel in the tank. Is it OK?

Thank y'all in advance!


Mody

armody

My Feedback: (10)

Some of the pix of my setup, though I have already explained it Still wanna share it[8D]

rebranger

You oughta run enough fuel line to male a loop all way round the tank. Leaves some extra gas for when doing hammerhead stalls or violent maneuvers

armody

My Feedback: (10)

Ed,

I can push this tygon line behind the tank, and it goes all the way down and connected to a brass tubing and of course it's open for vent!

rebranger

I use about a foot of line & circle the tank. Also I use chain saw felt type clunks, but u have to use a tank with a larger opening, fuel foaming doesn't have as much effect. When you get it broken in, you can go to 40 or 50 to 1 with Stihl Ultra Synthetic. I run 40:1 regular Stihl for breakin. No ethanol gas helps too. 

armody

My Feedback: (10)

Ed,

As I've been told that gas engines do not usually need the break in, run few tanks which I did and then go fly the plane. Engine gets settled down during various flights. DLE recommends to use 30:1 or 32:1 oil ratio, and you are suggesting to go to 40:1 or even 50:1, don't you think it would be excessively lubricant for DLE20? Is it really OK to go that higher on oil? Ain't it gonna potentially harmful for the motor?

I'm using 89% fuel, which is one graded up from regular and Klotz synthetic oil this is what I got in the first place and that is the first gas motor I own.

Our club's president is looking for the field and hopefully soon we are going to find one, as there are 5 places in his sight, and one of the place I've seen seems to be a good flying place. My previous field was hardly 4 miles, but newer ones are gonna be 15 to 20 miles, still ain't that bad.

Mody

rebranger

I run 'em on the bench first to check out the carbs (which are usually bad) crud from machining, jets stopped up, metering needle arm soft, etc.) use regular non syn oil @ 32, 32:1, then switch to syn @ 40:1 I've seen some go 50:1 with no problem, I run 'em just like a chain saw of which I have PLENTY, seems like I'm always cuttin a tree off a fence! Got about 6 DL's DLE's, a DA or 2, a Fuji, a Zenoa, & a box of the cheaper SV, RCG's RCGF's etc. Some crank right up & run great, others are a pain!! MOst times it's the carb or reed valves..
Check out that big pasture over on Cypress Rosehill road, 20000 block, right across from Breckindorf Dairy, it's been owned by a Taiwanese since the late 70's. About 80 acres.

rcguy59

My Feedback: (8)

If you value your warranty, use 30:1 or 32:1. If you need service, you won't be refused do to the damage having been caused by a lack of lubrication. Besides, oil is cheap compared to even a Chinese engine. Lots of oil MIGHT shorten the useful life of the plug. Too little oil WILL shorten the life of the engine. Do the math.

armody

My Feedback: (10)

Ed,

The one I'm using it's Klotz and it's synthetic so I'd continue to use synthetic. I'm impressed with your collection, and for me it may take years to get the collection. I'm planning to get another plane Seagull's Sea Fury, which I'm still waiting on money. I had started a thread of picking out one engine out of two and which is gonna be your choice that was the thread, it was between DLE20 and Mintor22, I was planning to get Dewoitine D.520 I was told, it ain't gonna fly good, or it would be difficult since it does not have bigger wing area, so I switched on Sea Fury both by Seagull models.

I have mixed up two gallons of fuel with 8 oz of Klotz synthetic. Anyway, I had been advised to get another DLE20 since I wanted to try Mintor22, though I love DLE20. Anyway, after I'm gone through my two gallons of fuel, you want me to switch to Stihl Ultra synthetic and go from 32:1 to 40:1? People have advised me to continue to use 32:1, as I'm a newbie to gas, and including you everybody's advices/suggestions I take respectfully here but, it's kinda making me perplexed.

As far as that big pasture you've mentioned, I don't think anyone's gonna go for it, since most of the people are around 249, 1488, 2978, 1774 and so on. We've been given an offer by Sparks club as I mentioned in my PM, but I don't think people are gonna take it, since our club's charges were dirt cheap as other clubs around.

Mody

armody

My Feedback: (10)

rcguy,

Just now I saw your posting, and I know you've been advising me to use 32:1. Now I'm asking again you guys are very respectable for me and I respect you all, there is no way I can beat down your experiences, so how come changing the oil from Klotz to Stihl and from 32:1 to 40:1 or even 50:1 is viable? As I'm running 32:1, and I think I'd continue to run 32:1 and I think Klotz oil is pretty good choice.

Thanks

Mody

rcguy59

My Feedback: (8)

Any oil recommended for air-cooled 2-cycle engines is OK. Some burn cleaner than others, but all will do the job if you use enough in the first place. At 50:1, you are asking a lot from even a very good oil. If the engine happens to run too lean due to a clogged filter or jet, etc., an already low oil mixture such as 50:1 can result in lube starvation of a fatal nature. At 32:1, you have more of a margin of safety. There is no good reason to get stingy with the oil if you have any hope of getting good longevity out of the engine. The other thing to remember is that the Chinese engines are infamous for their questionable metallurgy and bearings. They keep getting better, but skimping on the oil is still a very bad idea in my mind. Why take a chance on the engine just to save a little on oil? I have reduced my costs by using smaller engines. With a 20-35cc engine, you can fly all weekend on a gallon or two. At that rate I don't give a damn how much the oil costs, because I'm not burning enough fuel to even worry about it.