30.5cc engine. Maxing out fuel flow on a 1107 carb on my heli. Need more fuel and suggestions

[KevTrem]

1820 rpm on the head the engine is running at 12,503rpm. At 2000 headspeed it would be running at 13,740. On a heli I can tell you from experience a 200rpm increase does change tune a bit if you want peak power. I am tuning by ear and power delivery as well as checking the plug. It is not lean now but will be if I increase rpm or the air temp lowers etc. I am putting new gaskets on the engine between the carb/insulator/engine next week and will test again. If nothing

No because we use what is called a governor. It controls the throttle electronically through the servo to maintain a steady rpm that you set.

What I meant by free revving was the heli blades won't give a load on the engine like the transmission and mass of the land based models.
It takes a lot less effort to rotate a blade in the air than it does to rotate a wheel in contact with the ground.

On my 30DNT, I had the high needle 2.25 turns out on a 668 carb for it to run right, then I found I had an air leak.
I replaced the gaskets and checked isolator and now it runs a pinch past 1.5 turns out.

 

[Milo]

What I meant by free revving was the heli blades won't give a load on the engine like the transmission and mass of the land based models.
It takes a lot less effort to rotate a blade in the air than it does to rotate a wheel in contact with the ground.

On my 30DNT, I had the high needle 2.25 turns out on a 668 carb for it to run right, then I found I had an air leak.
I replaced the gaskets and checked isolator and now it runs a pinch past 1.5 turns out.

Thing is though Kev, as the blades move faster through the air, the air becomes more dense. This will give load. That's why the top speed of a car or plane is not linear to power. The faster you want to go you need exponetially more power. In simple terms double the power doen't equal double the speed.

 

[Seandonato73]

What I meant by free revving was the heli blades won't give a load on the engine like the transmission and mass of the land based models.
It takes a lot less effort to rotate a blade in the air than it does to rotate a wheel in contact with the ground.

On my 30DNT, I had the high needle 2.25 turns out on a 668 carb for it to run right, then I found I had an air leak.
I replaced the gaskets and checked isolator and now it runs a pinch past 1.5 turns out.

So your right and wrong, hes running a collective pitch heli, so the "load" is constantly varying with the pitch, the least amount of load is when it spools up in neutral, once it's airborne its a tad easier, but flying 3d is demanding on the engine, although my comments on why he thinks turning up the governor even 1k rpm means he needs more fuel, because the governor has full control of the throttle plate and he says he's tuned it without the governor connected for max rpm. If his tune was verified at full throttle plate, under a load, turning the governor up doesn't matter. the excessive (yes and I mean excessive) needle setting means one of two things (don't be insulted) either he's incompetent at recognizing an air leak and trying to compensate for it via the carb. OR there's indeed a carb issue.
Fact of the matter until he gets some tools and does some testing he (we) have no way of knowing.

To the op. Whom ever told you a 990 is any better then an 1107 is flat out full of crap. Sorry then run nearly identical, and with the choke removed the 1107 will out flow the 990. I'll go out on a limb and assume you not a carb guy (your not, it's OK, few are or care to actually understand, or attempt to, understand the how and why) like I've said this carb is rated by walbro to run on a 50cc engine. (As well as the 990) the likes of rcmaxx and and other mfgs set pop pressure and have great success with them on highly modified 50+cc engines. So this conversation is basically over until your able to do some diagnostics.

 

[sm1nts2escape]

I didnt tune it for max rpm. I tuned it for the headspeed seen in that video as I said before. I didn't say anyone told me a 990 is better I said I was going to test a 990 as well because my friends have that carb working well for them.

So your right and wrong, hes running a collective pitch heli, so the "load" is constantly varying with the pitch, the least amount of load is when it spools up in neutral, once it's airborne its a tad easier, but flying 3d is demanding on the engine, although my comments on why he thinks turning up the governor even 1k rpm means he needs more fuel, because the governor has full control of the throttle plate and he says he's tuned it without the governor connected for max rpm. If his tune was verified at full throttle plate, under a load, turning the governor up doesn't matter. the excessive (yes and I mean excessive) needle setting means one of two things (don't be insulted) either he's incompetent at recognizing an air leak and trying to compensate for it via the carb. OR there's indeed a carb issue.
Fact of the matter until he gets some tools and does some testing he (we) have no way of knowing.

To the op. Whom ever told you a 990 is any better then an 1107 is flat out full of crap. Sorry then run nearly identical, and with the choke removed the 1107 will out flow the 990. I'll go out on a limb and assume you not a carb guy (your not, it's OK, few are or care to actually understand, or attempt to, understand the how and why) like I've said this carb is rated by walbro to run on a 50cc engine. (As well as the 990) the likes of rcmaxx and and other mfgs set pop pressure and have great success with them on highly modified 50+cc engines. So this conversation is basically over until your able to do some diagnostics.

 

[Seandonato73]

I didnt tune it for max rpm. I tuned it for the headspeed seen in that video as I said before. I didn't say anyone told me a 990 is better I said I was going to test a 990 as well because my friends have that carb working well for them.

Wait im.now extremely confused. I asked if you disconnected the governor to tune for max rpm, you said yes. I took this as you tuned the engine for max rpm. If you tuned for max head speed your pig rich on the high side, and that would explain your excessive needle setting. There is a thin line for top rpm and too lean. More fuel will not net you more rpm. That engine your running will spin 20k rpm all day long. Your in essence miss tuning your engine for your slower required head speed. This is not how to tune the high jet. You tune it for max engine rpm, then set your head speed with you governor. All your governor dies is work the throttle plate to maintain a set speed under varying loads. Forgive the question, but is this your first gas powered heli? I did watch your video and assumed it was not, but now I'm wondering as your last comment isn't right for tuning a 2 stroke. Constant speed or not.

 

[RcJunkie13]

Ok so I don't know to much about helis... so he was basically tuning at a lower throttle postition than wot?

 

[Seandonato73]

Ok so I don't know to much about helis... so he was basically tuning at a lower throttle postition than wot?

If I'm understanding him right, then yes.

 

[TODD]

Any of the real hard maneuvers where the head speed is being pulled down will take it to full throttle during it. Sherman and the pros can keep them at max in some of these maneuvers.

This is 30 5 rcmk no load max rpm 1 5/8 high needle and 1 1/4 low.

Key words also. NO LOAD. Holding a throttle wide open does not tell you anything without a load against it.

 

[sm1nts2escape]

So with this is going to be my last post on this subject until I answer my own question if permitted. I appreciate everyone that took the time to read this, thought about this with an open mind and tried to help instead of clogging things up with non pertinent post etc. Thank you guys.

#1----------------------------------------------------------

Wait im.now extremely confused. I asked if you disconnected the governor to tune for max rpm, you said yes.

No you asked this.

Are you currently governed at the max rpm you can fuel

and I answered this.

I am currently tuned in perfectly for the governed rpm in that video. I did adjust the tune with the governor disabled to that headpseed. My highspeed is currently wide open now for that same governed headspeed.

#2-------------------------------------

Your in essence miss tuning your engine for your slower required head speed. This is not how to tune the high jet. You tune it for max engine rpm, then set your head speed with you governor. All your governor dies is work the throttle plate to maintain a set speed under varying loads.

What you fail to understand is that I am purposely flying the helicopter easily and putting less load on the heli than I am capable of due to me trying to get a nicely broken in engine as well as not having to fly my heli around during the break in at an extremely rich setting. Your idea of tuning a governor/engine in is partly correct but almost entirely false. With Helis you tune your engine in per your flying style, Highest set headspeed and collective pitch settings. Not per max power at max at max rpm like you would do a dragster or chainsaw. If everyone did that most peoples helis would be extremely rich and making way less than optimal power during the entire flight.



#3------------------------------------

More fuel will not net you more rpm.

I have repeatedly said that I am not trying to gain more rpm by adding fuel. I have said repeatedly that I am trying to safely raise my rpm and need more fuel to do so.

If I had to guess I need about 15% more fuel on the high for when I turn the rpm up more.

I am running my high needle maxed out at 3 1/2 turns already and I am not completely broken in yet. I could have used an 1/8 turn more on the high today but I simply can't get more fuel out of it and soon the engine will be completely broken in and I want to up the rpm of the engine some more and will definitely need more fuel to do that. As I said I am guessing I need about 15% more fuel to get where I want.

I need more fuel especially when I raise the rpm of the engine. I just need more fuel because it is going to be lean when I start raising the rpm beyond what is shown in that flight video.

As the engine is breaking in it is requiring more fuel and at this point I am on the verge of running out of fuel if it seats in even more which I am told the engine still has a few more gallons to go before it is (3gallons more). So with that I know that this carb will eventually not supply enough fuel at the rpm it is currently running at and definitely not enough when I increase the headspeed another 200rpm. Not to mention my post didn't even mention ambient air temp changes.

#4---------------------------------

Forgive the question, but is this your first gas powered heli? I did watch your video and assumed it was not, but now I'm wondering as your last comment isn't right for tuning a 2 stroke. Constant speed or not.

I am new to gassers so all help is appreciated.

So as you can see I stated I am new to RC Gassers. However I am not new to tuning in Carbureted Gas engines or various other fuel powered engines and their delivery systems. I came on this forum hoping for help from people that have pushed things farther than most because the Rc Gas Heli world is just now starting to gain popularity due to recent improvements in power, weight and vibration. I don't mind criticism and I take it weekly with my chin up and even give some of my own here and there when deserved but deliberately ignoring parts of a conversation, putting words in peoples mouths and belittling people only to increase your perceived status to people who are only looking for help is a huge turnoff for me.

 

[KevTrem]

The problem you have here fella is we are pretty much all land based models and tune for that, some are water based. We are learning about the heli's as you tell us. So there is some very knowledgeable people on here who could design, machine and build their own engine plus carb, but we can only work on the info you have given us.

Throw some pics up, also links to any youtube videos you have of the heli, it'll help us all in trying to help you. Plus who doesn't like pics and video's of anything RC??

 

[Milo]

The only polite way I can put this is, you are mistaken in your knowledge of these engines and the people on here.

Nothing has been said to raise anyones status, no one gives a fcuk. You are being offered very good advice but you insist you know better, so all anyone can say is good luck.

Your comment alone about the differences between an 1107 and 990 show your lack of knowledge, never mind anything else you've stated. You are clearly doing something wrong or don't understand what you are doing, otherwise you wouldn't be on here asking for help.

With the information you've provided there is no evidence that you would run lean on a RPM increase. There is something fundametally wrong with your carb settings and engine speed.

 

[sm1nts2escape]

The problem you have here fella is we are pretty much all land based models and tune for that, some are water based. We are learning about the heli's as you tell us. So there is some very knowledgeable people on here who could design, machine and build their own engine plus carb, but we can only work on the info you have given us.

Throw some pics up, also links to any youtube videos you have of the heli, it'll help us all in trying to help you. Plus who doesn't like pics and video's of anything RC??

I understand this and just so you know this wasn't directed at you or most that commented on here. Only two people inpaticular and one had his post removed already. I appreciated you trying to help.

The only polite way I can put this is, you are mistaken in your knowledge of these engines and the people on here.

Nothing has been said to raise anyones status, no one gives a fcuk. You are being offered very good advice but you insist you know better, so all anyone can say is good luck.

Your comment alone about the differences between an 1107 and 990 show your lack of knowledge, never mind anything else you've stated. You are clearly doing something wrong or don't understand what you are doing, otherwise you wouldn't be on here asking for help.

My post wasn't directed at you but you seem to be upset and I am sorry about that. My comment about a 990 vs 1107 was this. Please read it carefully.

as well as trying a 990 carb as I have been told by other heli guys that that carb is bulletproof and works well

 

[Milo]

The only real difference between a 990 and 1107 is the choke.

I think the orginal point of you running the highspeed wide open and thinking you need more fuel is the issue. Prove it by increasing the RPM for a short period and show us you are lean or take head temp readings and post them at different RPMs.

Based on what you are saying there is no evidence that you are going to run lean by increasing your RPM.

 

[RcJunkie13]

So with this is going to be my last post on this subject until I answer my own question if permitted. I appreciate everyone that took the time to read this, thought about this with an open mind and tried to help instead of clogging things up with non pertinent post etc. Thank you guys.

#1----------------------------------------------------------

No you asked this.

and I answered this.



#2-------------------------------------

What you fail to understand is that I am purposely flying the helicopter easily and putting less load on the heli than I am capable of due to me trying to get a nicely broken in engine as well as not having to fly my heli around during the break in at an extremely rich setting. Your idea of tuning a governor/engine in is partly correct but almost entirely false. With Helis you tune your engine in per your flying style, Highest set headspeed and collective pitch settings. Not per max power at max at max rpm like you would do a dragster or chainsaw. If everyone did that most peoples helis would be extremely rich and making way less than optimal power during the entire flight.



#3------------------------------------

I have repeatedly said that I am not trying to gain more rpm by adding fuel. I have said repeatedly that I am trying to safely raise my rpm and need more fuel to do so.






#4---------------------------------


So as you can see I stated I am new to RC Gassers. However I am not new to tuning in Carbureted Gas engines or various other fuel powered engines and their delivery systems. I came on this forum hoping for help from people that have pushed things farther than most because the Rc Gas Heli world is just now starting to gain popularity due to recent improvements in power, weight and vibration. I don't mind criticism and I take it weekly with my chin up and even give some of my own here and there when deserved but deliberately ignoring parts of a conversation, putting words in peoples mouths and belittling people only to increase your perceived status to people who are only looking for help is a huge turnoff for me.

This guy reminds me of someone... who can guess.
Anyways... you keep on thinking you are right compared to the very experiences and knoledgeable people in this forum. They try to help then you keep saying otherwise. Like you say, you are new to gas helis, so I definitly think that you should listen. Switching to a different carb model will make little difference unless the carb u are using is defective.

 

[Milo]

My post wasn't directed at you but you seem to be upset and I am sorry about that. My comment about a 990 vs 1107 was this. Please read it carefully.

No dude, I’m not upset. I find this quite amusing actually.

The way this will play out is entirely up to you but I suspect it will end here.

 

[DougStar]

This has been exhausting

 

[Seandonato73]

Ok this will be my last post on this subject. If your familiar with tuning other engines, specifically 2 stroke, you know all that matters is you idle setting and high speed setting, as the carb has transition jets to compensate for fluctuate throttle plate movements, and transition smoothly between the low circuit and high circuit.
youll also know that the governor has full control of throttle position. Where you have your governed rpm set, has zero, I will repeat zero, Effect on how the carb fuels the engine. It's sole purpose is to maintain a set rpm. As I have said, you need to disconnect your governor to maintain full throttle, under load to adjust the high speed needle. Since last I check this is how all 2 governed 2 strokes are set. At max engine rpm. Now im not all knowing, nor do I claim to be, but I have yet to have any issues setting up engines 2 stroke engines like this. Whatever your doing something is amiss. I can't point to what exactly it is, and admit to having limited large scale flight experience. That was my great uncles thing, unfortunately he is no longer with us to ask. Once you figure out your issue, I and other would appreciate you coming back and letting us know what the issue was. Beyond what we've said, and advice given you'll not receive any more input, until you do your part.
I will also add there are forums dedicated to large scale flight, you should seek advice with these other outlets.

 

[Rep732]

 

[1Coopgt]

Dude I found a carb for you. You said you have a lot of experience tuning engines/carbs so I know you got this.


Now that I've got that out of my system . You really should be listening to Sean . He is one of the most knowledgeable people I know on this forum. You came to this forum asking for help and then you are nice enough to totally ignore the folks that are trying to help you. Either take the flight stick out of your ass and start listening or take a freaking hike . This is going no where and you're just being arrogant. Good luck . Cool helo.

 

[sm1nts2escape]

Now im not all knowing, nor do I claim to be, but I have yet to have any issues setting up engines 2 stroke engines like this. Whatever your doing something is amiss. I can't point to what exactly it is, and admit to having limited large scale flight experience. That was my great uncles thing, unfortunately he is no longer with us to ask. Once you figure out your issue, I and other would appreciate you coming back and letting us know what the issue was. Beyond what we've said, and advice given you'll not receive any more input, until you do your part.
I will also add there are forums dedicated to large scale flight, you should seek advice with these other outlets.

Thank you for that and I think we can agree to disagree partly on the governor tuning part. Also, I want to apologize for coming back a little stronger than was needed. I had a bad day and should have let most of it go and that is on me. Please accept my apology. Now for some news. I took the heli out yesterday primed the carb first then couldn't get it started. After richening up the low speed I got it started and got massive backpressure through my clunk which created a foaming tank and then my primer bulb filled with air. After I got the air out of the primer bulb the engine died from going rich. I leaned it back out and it seemed fine on the ground and fourstroking slightly with a touch of smoke at idle like I like. After take off as soon as I put it under load the engine was leaning out much more drastically than before to the point my governor wouldn't hold it anymore (overshooting rpms after coming off load) and I was hitting throttle hold to land it and let the engine smooth out/cool off. No matter what I couldn't tune it out so I completely redid my vent line at the field and it had no change at all to the tune so I took the heli home and inspected my carb. I found an airleak on both of my 1107 carbs in the exact same spot plus a couple specks of dirt but nothing more. I am wondering if when the engine is pulling a hard vacuum air is rushing through here and messing with my tune when doing those maneuvers that put heavy load on the engine/vacuum on the carb. I have a 990 that is being delivered today along with some new gaskets so I can see if the 990 has the same leak and if it behaves the same although I doubt it will as I said before I have some friends running them without issue and my friends that are running the 1107 had the same issue in flight as I am having. Also in regards to the comment about large scale flight I figured you guys would have done more testing on this carb then them so came here first. Sorry again.

Dude I found a carb for you. You said you have a lot of experience tuning engines/carbs so I know you got this.
View attachment 73598

I've had many and have built over 40 cars now. From modified imports like FD rx7s to souped up hotrods. My favorite out of all of them was my 85 Chevy shortbed with a built 406/th400 running a Holley Truck Avenger 770 Steel bodied carb. The new ones are aluminum to save weight/money.