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01-14-2011 02:20 AM  7 years agoPost 121
slickporsche

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American/Philippines

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to Dr. Ben
Why would anyone do 3D to a perfectly good helicopter and engine. If you are bent on destroying it, then grab the thing by the tail and bash it into the concrete a few times. Then rebuild it and do it again. Not much different.

For the guys who can afford to beat the living crap out of an expensive bird, go for it.

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01-15-2011 10:19 PM  7 years agoPost 122
wjvail

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Meridian, Mississippi

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In the 4-Cycle world (F3A, top placings at WC forever), YS has gone from a 120 (18-20 years ago) to a 175 (today) and used the same lower crankcase, and same rear bearing.... This is an example of the motors getting more powerful, more dependable, swinging heavier loads and mass, and useing the same lower bearing and crankcase.
Jim... At some level you've made the point some of us are trying to get across. In the above you mention YS stretched the lower end of a 1.20 into a 1.70 Well, in the heli, world YS stretched the YS .61 into an .80 and life was good. Then the .80 became a .90 and we have had an acceptable engine. I would argue that the engine would be better if it had been designed from the beginning as a .91 but we have been unwilling to make changes to our airframes to accommodate a physically larger engine so we live with a .90 in a .60 case. That's not just YS. It includes all engine manufactures. It's what WE asked for. It's what we accept from engine manufacturers.

The reason this thread keeps going is that it appears that now the case will be used for a 1.20 and that doesn't sit well with me and a few others for a number of reasons.

Simply put, in your example above the once 1.20 4-Cycle used in F3A would now have to be a 2.40. Notice that the 1.20 4-C hasn't yet grown to a 1.80 as it would have to, to be comparable to a .60 becoming a .90. Your suggestion that because YS has been able to use their F3A 1.20 case for a 1.70 only reinforces my suggestion that using the .61 case for a 1.20 is simply too restrictive (for me).

There are other less obvious but very real considerations. For example, the aspiration of a 4-C engine is entirely through the cylinder head. Other than fixing the crank, the lower end of a 4C doesn't do much. It is NOT part of the valving or timing of the engine as it is in a 2C. (Yes I'm aware the YS induction system is more complex than say a Satio but for this argument, it isn't a significant difference.) By bolting a 2.40 jug on a 1.20 case, YS would be afforded the luxury of up-sizing the entire gas flow path. In a 2-C engine, the carb is located such that the crank functions as a rotary valve and the inducted gasses must pass through the crank and by inference, the gasses must pass through the rear bearing. The bore through the crank begins to severely limit the performance of the engine. The equivalent would be to stretch the 1.20 4-C you mentioned to a 2.40 but for design reasons, you had to REDUCE the size of the intake tube, valves and exhaust. Would you have a concern if the YS 4C 1.20 were enlarged to a 2.40 and all carburation HAD to pass through the rear bearing?

These same principles apply to the transfer and boost ports in the new 2C heli engine. I can only assume YS is growing the .60 to a 1.20 by increasing the bore and that has the potential to REDUCE the size of the porting paths in the engine. Again these would not be an issue in increasing the size of a 4C.

I'm traveling right now and away from my camera and engines so I can't take more picture to make my point. I'll try and do a follow up when I get home.

Bill

"Well, Nothing bad can happen now."

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01-15-2011 10:28 PM  7 years agoPost 123
DS 8717

rrProfessor

Here wishing i was somewhere else

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That not true with the YS it draws air into the crankcase just like a 2 stroke,only throudh the rear of the case instaed of the front(there are 2 stroke that intake from the backplate also.

YOU ONLY LIVE ONCE..IF YOU LIVE IT RIGHT THATS ALL YOU NEED

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01-15-2011 11:28 PM  7 years agoPost 124
wjvail

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Meridian, Mississippi

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That not true with the YS it draws air into the crankcase just like a 2 stroke,only throudh the rear of the case instaed of the front(there are 2 stroke that intake from the backplate also.
Alright... This is getting a bit more complex and a little off the subject but you're correct. A YS 4C does induct air into the rear of the case. However, the lower case is functioning as a "pump" to charge an air-chamber that in turn feeds the head and valves. The lower case functions as a sort of "supercharger" for the engine. The larger displacement of a 2.40 in a 1.20 case would simultaneously increase the "size" and efficiency of this "supercharger". In this instance the smaller volume of a 1.20 case for a 2.40 engine has the potential to actually improve the pumping efficiency of the "blower". Still, the YS 4C crank is only serving as a driver of the rotary valve and does NOT time the engine nor does its size help or hinder the airflow in the engine as it would in a 2C. Using a 1.20 sized crank in a 2.40 4C would not have the same restrictive effect it would on a 2C.

Cheers,

Bill

"Well, Nothing bad can happen now."

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01-16-2011 01:48 AM  7 years agoPost 125
REGULATER

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Bakersfeild, CA

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I can't believe all the speculation on this motor, Like I said the motor is still in the testing stages, why don't you guys just wait untill the motor is availible . YS is not going to release the motor if it does not perform up to there standards.

Mark

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01-16-2011 05:25 AM  7 years agoPost 126
Inspector Fuzz

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NLA

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Like I said the motor is still in the testing stages, why don't you guys just wait untill the motor is availible .
I have a brain and I have devoted a big chunk of my life to playing with various kinds of reciprocating internal combustion engines from tiny model diesels to double overhead cam V-12's. I can listen to a motor and tell what it needs in the way of fuel to air ratio. I can identify the faintest sounds of detonation.

This issue is very simplistic and patently obvious to me. I feel sorry for those in the world who are too obtuse to recognize it.

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01-16-2011 09:51 PM  7 years agoPost 127
wjvail

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Meridian, Mississippi

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I can't believe all the speculation on this motor, Like I said the motor is still in the testing stages, why don't you guys just wait untill the motor is availible . YS is not going to release the motor if it does not perform up to there standards.
This is a discussion forum right? If YS is showing a new engine at trade shows and reps are commenting on its performance, it seems to me to be fair game on a helicopter forum. We are simply discussing what appears to be YS's next offering.

As you say, YS will not release the engine until it is up to their standards. I think what keeps this going is that a 1.20 in the .60 case is not up to my standards. I might be so bold as to say that for the price of a "90 class" engine, it shouldn't be OK with you either.

"Well, Nothing bad can happen now."

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01-16-2011 11:20 PM  7 years agoPost 128
CoronaL

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Winnebago IL

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lol then don't buy it. If people like it and want it, I don't care if they put a 2.4 size motor in a 60 crankcase as long as it works well.

Randy!!! I am the liquor

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01-17-2011 12:21 AM  7 years agoPost 129
Inspector Fuzz

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NLA

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Most folks that buy it won't be able to tell whether it works well or not.

It it starts and continues to run throughout an entire flight, the majority of the helicopter community will believe that it is great.

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03-14-2014 01:51 PM  4 years agoPost 130
wjvail

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Meridian, Mississippi

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This is a three year old thread worth reviewing...

Any thoughts on how this engine worked out? Any lessons to be learned? Any ideas for the "next wave" of new engines?

Bill

"Well, Nothing bad can happen now."

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03-14-2014 11:08 PM  4 years ago •• Post 131 ••
CoronaL

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Winnebago IL

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IMO the motor works well for most people, but is harder to tune than most people would want to suffer through.

For very demanding pilots I think the verdict is not great. I believe the motor suffers heat soak and limits the ability to tune the motor for power in some climates(hot, humid etc..)....

Would most people notice that, NO! Would it annoy most people, yes! Just knowing that would annoy many. What I think the biggest issue is, is the tuning. It's just not easy enough to tune for most people, and I'll offend many by saying this, but IMO 80-90% of nitro heli pilots really can't tune well. They might be able to tune enough not to blow up a motor, but to really really tune a motor for good power throughout the high, mid, low needles is a very very hard skill to learn. Most don't possess that. The more power you make, often times, it's at the expense of tuning; everything else being equal. I'm sure I'm over simplifying that argument, but from porting motors I've realized I can make some wicked power out of them, but tuning often suffers for it. Balance is the key and for stock motors the manufacturers error very much on the tuning side as they have to account for a population that cannot tune well, plus a variety of other factors, non standardized mufflers, fuel etc...

Randy!!! I am the liquor

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03-15-2014 04:09 AM  4 years agoPost 132
knightofcarnage

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chicago

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Tune becomes very easy with a blader system , but most don't want to try it and give up.

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03-15-2014 01:04 PM  4 years agoPost 133
DS 8717

rrProfessor

Here wishing i was somewhere else

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I've been using YS for years,pretty much my only choice of engines.It seems to me people are trying to run the engine too lean,my experience is to run them slightly rich as they have plenty of power and the 120 should be more than enough for almost anybody......Also they are trying to tune them like other brands of engines and they dont tune the same, they are actually easier if/when you understand how the needle valves work...If you dont use a bladder you need to tune it for the last few minutes of the flight when the fuel level is lower and not for the first part of the flight which should be a little bit richer than the last part of the flight.....

YOU ONLY LIVE ONCE..IF YOU LIVE IT RIGHT THATS ALL YOU NEED

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03-15-2014 09:50 PM  4 years agoPost 134
ExFokkerFlyer

rrApprentice

Coarsegold, CA

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Been flying mine quite a bit this season so far and it's still running strong. Secret with this motor (or most motors really, definitely YS) is to run it rich like DS 8717 posted. As the weather has warmed here in Cali, 60s two weeks ago, 70s this week, and 80s this weekend) I've had to richen it each outing.

I've heard the phrase "find lean" and then richen up from there... while there is nothing wrong with that if you go far enough into the rich "band", I've found better luck on the 120 to go the other way. I like to start rich and slowly lean until I get the engine running fairly smooth through out with a constant plume of smoke. The goal is to be substantially on the rich side of "peak", which ends up being more power anyway. I start each day going rich a couple of clicks and spending the first couple minutes of the first flight adjusting it a little leaner. If you are confused which way to adjust the 120? Go rich first...

It is easy to end up being too lean if you are going for "peak" power. I've had it in a power band once that could put some electric 700s to shame as far as pure punch out power. There is plenty of smoke, so it appears to be fine, but if you listen carefully, there is a metallic pinging present. Almost sounds like something is loose on the heli. This is too lean and will lead to problems, and if you put a load on the heli at this setting and keep it there, it won't hold up and you could burn up the motor real fast. With it five or so clicks rich of that (not an exact amount just an example) you may not have the same break away power, but you will be able to sit there doing aileron tic tocs the entire tank without the engine really even caring what you are doing to it...

Don't let this scare you, as any engine can be burned up on any given day if it's not tuned right. The 120 is not a hard engine to tune really, it's just talking to you in a slightly different language than other motors. Be patient, err on the side of rich, and you'll be fine.

The 120 really comes into it's own with it's torque, and being able to keep the heli going with a constant load, and doing so fairly rich.

Tom M

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