MTK,

Don't get upset please, this forum is suppose to be part of this hobby, the fact is nobody tells how much money people put in a top pattern plane, and that is really the cost, the Amethyst is the best selling F3A byplane ever, I think even monoplanes, and if anyone make a big effort and buy one, it will do it with good stuff, at the end, we all need to compare apples to apples, it is just not fare to do like some people post someone is smarter because it can do the same with 20% the price when actually in serious competition you don't see what people usually write in the posts.

BTW, last time I tried a driver, the pieces of grass were flying farther away than the actual ball, you can guess how far that is.

Good luck with DLE project, I always follow your research, hopefully you will make it work for pattern.

Regards

Alejandro P.

Hi Alejandro,

Most of the guys down here use the small 1000w Honda generator. They go for ~$1,200.00 down under. I bought the 2000W unit for $1,800.00. It's a bit heavier (21kg from memory) but it's dual purpose. I can run the refrigerator and water pump (tank water) when we have a blackout at home.

At my home club we have a few 100+AH deep cycle batteries connected to a regulator and solar panel. This works well but is actually proving to be too popular... lol

Regarding the YS using petrol, I think that if they can reduce the cost in any way it's a good thing. So long as performance is maintained and reliability. One has to wonder if LPG would be a viable option. We now have LPG Injected cars that outperform the petrol equivalent. They are also cheaper to run. I was told last night that even super charging or turbo charging is now an option with LPG....

Another question arrises, why does YS (and other 4 stroke MFG) have oil in the fuel rather than a wet sump? Must be a good reason for this.

Cheers,
Jason.

Hey Jason,

After writing I went and check on Amazon for the Honda and nothing, oh well.... the battery power supply with the solar charger sounds very good, but if that gets done in south america it will last just a few days, somebody will quickly steal it, that is our reality, jejejejeje, maybe not all countries, in Venezuela it will last until the last car leaves the field!!. Sad but true.

On the wet sump, I think a main reason is because wet sumps can only be in one position, unless you use a more complex lubrication system like the one used in full scale aerobatic airplanes or engines modified to operate in any attitude, usually they are the dry sump type, just like the RC engines but with a external oil tank etc.

In Venezuela the LPG has been used for years, still cheaper than gasoline, where you can fill a car tank with $0.03 cents, but it does not have the same power, of course our city has a lot and I mean a lot mountains and the terrain is not flat in about 60% of the city, that sure has to do with the power, the most important reason for LPG besides cost is the exhaust gas is water vapor, and that is very cool.

Regards

Alejandro

As the original poster, maybe I need to clarify. I hate electric. It has no soul, and doesn't interest me in the least. I fly for fun, as I will never be Andrew Jesky, and I suspect there are a lot more people flying pattern for fun than are doing this for a living. To me there is nothing "fun" about electric, so no matter if it is better, and all the "cool" guys fly electric, I don't want it. I like cool engines, and YS are cool, no doubt the pinnacle of alcohol-fuel production engines. But they are 1) expensive, and 2) exorbitant to operate. I can live with being expensive, but I hate high operating costs. So does everybody, remember, even sport fliers are leaving glow for electric and gasoline. So the future has to be bleak for YS, just look at Kodak. YS could get into electric, but seriously, what could they offer that Hacker, Neu, etc. doesn't already offer? Pattern is switching to electric, sport fliers switching to electric or gas, yeah, they make the best heli engines, but I am sure they will be moving to electric or gas too, they are not immune to the price of glow fuel. So who is going to buy enough glow fuel engines to keep YS in business? And that is not even mentioning other disadvantages such as corrosion and availability. Ever run out of glow fuel on a Sunday? Most hobby shops are open only during business hours and less than 7 days a week. And that is assuming they have your fuel in stock. I'm sure the technical difficulties are daunting, but what choice does YS really have? If YS wants to continue in the model engine market, they better figure out how to make a gas engine in the next few years, or they will be bankrupt and without a market like Kodak.

MT I'm not saying that it cant be done or that you dont save, its just that people who fly YS use it because they want the best engine and the best power source out there, not because its cheap... for example, I'm sure a non carbon golf club is cheaper.... but you want the best!

more economy is good, and people will like it, IF it gives you same performance... for example, the CDI, that saves a lot of fuel and has the same performance or better than glow plugs, total success!

its like sports car.. none will give you fuel economy... you just want the power!! no one when buying a ferrari, porsche, Lamborghini, etc is looking at its fuel economy. in this case YS is the Ferrari of F3A engines

you are right! in the cost you should include the purchase and maintenance of the engine, trust me after 350 flights... you wil need a new DLE

about the wet sump, another reason is why carring the weight of the oil??

Guys that can afford to buy a Ferrari, or any other super duper super woopie car, agreed, don't care about its care and feeding since they can afford that too. That's just not true with a YS 4 stroke, world-wide. Yes, there are a few for whom money is no obstacle but for the majority it just isn't the case.

As far as economic offerings, my experiments are too new. You haven't seen what I have seen, but I hope to have the pattern plane flying this summer. Then we'll talk again.

The DLE is no panacia by any means. It has taken quite a bit of development and re-thinking to make it pattern - viable. I have 4 gallons through it or around 70 flights. It's fully broken in but that's all. I may learn something on its life span come summertime. On the other hand, at 370$US from Tower, it's cheap enough to throw away after it breaks. What I don't know is how you can claim that the DLE will require replacement after 350 flights. Are you talking from experience or through something else?

But I know one gentleman whose opinion I truly trust that swears by them. He is a long time motorcycle builder who has been doing that for 50 years. He was a fine Pattern flier and team member as well in his youth. He tells me that the fit of certain parts is superior to DA's and he feels that every run is better than the last. I admit that I've seen similar results over the first 70 runs but I have no DA to compare against

"after 350 flight you will need a new DLE.."<div>
</div><div>LOL,</div><div>
</div><div>plenty around here with more the 3 times that amount of flights.</div><div>Theres a couple of RCGF engines with well over 500 flights at full throttle 90% of the time and they fire first time.</div><div>
</div><div>"When did ignorance become a point of view?" Scott Adams</div>

I'd have to say my maintenence bills for the YS so far puts the fuel bills to shame.

There's no argument that running petrol will drop the YS running costs if the maintenance requirements don't get worse, but I think YS would need to bump up the capacity to retain the performance. Considering that the crankcase is probably due for a redesign it might be the time for YS to consider a 2.20 sized petrol (with optional methanol kit), if they could keep the weight, heat and vibration under control.

There's certainly no lack of space in a modern F3A engine bay for a physically larger engine.

So if YS doesn't come out with a reliable gasser, there are no options??

That's a pretty tight corner you've boxed yourself into!

DaveR
Can it be done by YS to produce an equal powerful engine running on petrol with the same physical dimentions as theirs methanol/mix engines? I do not think so, but if they do it, horray I was wrong.

I will try to substansiate the above. (Some math will be necessary to explain this)
2 and 4 stroke engines.

4 stroke Volume svept= n cylinders x pi/4xbore sq x lenght stroke

2 stroke, if the exhaust port closes some distance before tdc (top dead centre) then the trapped svept volume is:

2 stroke Volume trapped = n cylinders x pi/4 x bore sq x lenght stroke

This volumes can produce the work:
2 stroke Work indicated = imep x volume svept x rps

4 stroke Work indicated = imep x volume svept x rps/2
(imep = Indicated mean effective pressure)
(rps =revolutions per second)

Interpretation of the last one. A 4 stroke engine of equal power of the two stroke (Work indicated), with equal svept volume must have an imep value that is double of the two stroke engine. One can play with these three factors but the end result should be the same. Question, how practical will it be with a 4 stroker reving 16-20'?

I hope this will help to understand why i donot think a 4 stroke petrol engine will be as powerful as a methanol/mix engine compared as apple to apple. YS can make their engine more powerful by increasing svept volume and so on but that will be a totally different engine.

The YS 4 stroker really is a fantastic powerful engine running on methanol/mix. The CDI has the advantage that it donot need a lot of fuel to correct the ignition timing as glow need.
Hope I did not offended someone.

Best regards

Hey that's a good caption....I doubt that Scott Adams lived in the day of the RCU discussion list...

RCU, synonymous with the proverbial gumball machine

Or some outside the norm thinking.

I would think that a purpose built engine
Would do well.

In a perfect world: The 4 stroke engine would be gasoline, high compression, compressed supercharged/turbo, large intake valve ,
With ignition, and bearing in camshaft.


Or scrap the 4 stroke use a two stroke
And use some sort of power valve like the motocross bikes use.


Above all this though, it comes down to ease of use, and amount of time needed for
Maintinence.

Obviously this is the biggest factor that causes one to
Shift from glow to petro.
As we all know, it isn't because gas is lighter or
more powerful. It is because of ease that goes along
With it.

So, after some discussions in this thread I remembered something very interesting, in the WC in Argentina 2007, Daniel Falco who was the FAI Juror and several times south american champion in F3A, flew a Camodel Scandalous Bipe with a DA 50 in it, it flew very well, it flew with winds of 20mph, the engine was completely concealed if I remember correctly, so it is already proved as a viable concept, nothing new there, but not for FAI, maybe that is where we all argue and just fly different classes, a gas engine could lightened up and cooling can be improved like on the RC Cars where the fins of the head are drilled through, something that has been for for more than a year now, but the noise will probably not pass, or weight or both, but it is still a solution for many who can not afford to buy the best and lighter equipment and fly AMA in advanced or lower.

If some one thinks YS will go out of business if they don't go gas, well , everybody is entitled to it's opinion and that is why the forums were born, but YS will not go out of business just for that, same as Futaba will not go out of business because the 18MZ is too expensive and someone doesn't like the color or the camera.

Last but not least, the electric thing is good, but for the people who travel to international competitions it will get more complicated as the regulations that are in works will ban the air transport of Lithium batteries, will see what happens.....

So at the end what do we have? We have a specialty with different classes where almost anyone can get into and get the equipment it can afford or simply want to spend so much on, and that is the good part, is someone wants the cheapest Chinese aircraft and equipment he can spend on ,and can compete with it, he can, or someone wants the most expensive and best, he can also, and that makes all this discussions worth something. There is something for everyone at every level.

Regards

Alejandro P.

double post

What is your point? You keep rehashing old business. And then you try to take a swipe at my developments just because I put them out there for everyone to view? Go pound salt

On air transportation of large capacity lipos, a simple solution exists , which is to ship them ground/ over sea earlier or borrow from somebody in the host site.

You are correct, but then there is the issue with customs in other countries and when shipping Hazmat you need a special license or a company to do it for you. I think a change in the chemistry is been worked due to that, and cell phones and laptops is what probably is holding the ban so far.

kochj

THis power valve is a mechanical device that lower the exhaust port for the purpose of get more power (not on of motor)at low revs. Normally the engine is built to a narrow powerband and the above widens said powerband.
Clever device!!!! Can it be built into a hobby engine??????

Best regards

Absolutely it can be built into an model airplane engine. IIRC early motor cross bikes had centrifugal /mechanical power valve systems, where the road bikes were electric. Three types I'm aware of are the rotary type of the early Yamaha's (RD'S,RZ's, TZR's), multistage guillotine (RGV250), and single stage guillotine (TZ's). I can say in all cases while the bottom ends are improved, the transition wasn't 4-stroke smooth on any of them but that could have been purely due to other design considerations.

Don't forget Yamaha 4-strokes motorcycles have had their EXUP system for 20+ years which is a valve to vary exhaust backpressure.

Apart from weight, I'm surprised this hasn't/wasn't offered by OS on an F3A engine but I guess Fuel injection didn't require new crankcase molds where power valves do...

Largely I agree with you, tha it is diffuclt for a 4 stroke MeOH engine to transfer to pertrol power and maintain dimensions. However it is a design problem so I won't be writing anything off just yet.

2 strokes have some inherant drawbacks, poor cylinder scavenging being one and failry low compression ratio is another. Four srokes have them trumped here.

The really big issue with petrol engnes is that very very few have been designed for the RC hobby. I believe the DLE20 is the first and for teh first time theres a petrol option that delivers performance lsoe to its MeOH equivalant (OS 120AX).

Any engine takes time and money to develop and with the RC hobby being small once a design is into production only incremental changes are made till the initial investment is recouped and a new design is started.
OS GT33 is the next purpose built RC hobby engine I.e. not one that has a development history dating back to a botany implement.

What MeOH Rc engine have on petrol engines is 50 years more development for a very specialised market. And typically the engine as been designed in conjunction with its exhaust to achieve best results.

UAV'sare going to push petrol engines forward and then we'll see what potential really exists.


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hi guys,
I agree with your demonstration but the formula you give only and your demonstration only allow to compare atmospheric engine between them. you forget a little detail which change all.
the YS 4stroke are supercharged and in this case the effective volume of mixture pumped to be burned in the cylender is greater than the volume svept of the engine .
in the YS 4stroke engine the supercharging effect is achieve by to systeme :
first : it is the rotary valve which produce the overpressure in the cylinder during the pumping but it is not enough
secondly : the fuel and especially nitromethane allows to give more oxygen in order to supercharge the engine, it is for that reason that people use 30% of nitro in the fuel

for example if you suppress nitromethane in the fuel, there is not any interest to use an YS instead of others engines running without nitro fuel.

What Steph says is true, we can run the YS with no nitro with the CDI, but what is the point then? we still use 30%, now 25% on the 175, the manual says 25%max on the 170, and we have been running 30% in them since day one with no problems at all, I only got a bad pump during training once on the 170CDI version(that was the pump with problems), but that is it. Even thoug we know it can work with less nitro,there is a difference of $12 in price per gallons, wich is alot,but there have been situations where full power was needed at least one or two times during a schedulle, a high power output is a must, we use the highes nitro content possible anyway. Anyone who flies at sea level should be ok whith 15% I think.

MVVS, ZDZ are engines designed from the ground up for RC use, and also Desert Aircraft engines are, so the DLE, Turnigy etc are copicats realy,I hve a Turnigy 55 and is almost identical to my DA's, the OS it is indeed RC all in it's own, but one of the most important factors during the design in the case of th the DA was what they called the aerobatic power curve, so raw power will not do good if it can not effectively be controlled, we all know two clicks on the throttle control can change a lot in a maneuver, so the presicion needs to be there.

One important thing as Timble says is, the UAV world can have the resources for this, DA was selling only 50% of it's production to the RC industry, the rest was going to drones and UAV's, that was about 4 years I think, last time at was at their factory, but their designs are tweeked to the max but nothing really new on the cilinder/piston combination.

What I see is, if ZDZ who really developed and engine specifically for F3A and then abandoned the development, then who else will pick up the proyect? that is the big question, maybe someone should ask ZDZ to find out what happened, maybe they did not get enough orders and dumped the proyect? I wonder because I think DA has sold more than 7000 DA 50's alone, I wonder how many ZDZ40F3A were produced and sold.

Regards

ZDZ 40 didn't have enough power for the Master-AMA schedule. I tried with pipe in the middle of hot humid summer. Probably a good reason why didn't work for F3A. The plane was 5Kg with wood prop. Pattern pilots find out very fast when something new does not really work.

A point lost in all this 2-stroke/4-stroke efficiency discussion is that twice in the recent history (last 20 years) of F3A, 2-strokes got dumped very quickly as soon as a decent 4-stroke alternative came along because they turn bigger props at lower RPM and have bottom end grunt. Characteristics I might add forced upon us by the design of the schedules, because a snaproll at the bottom of a loop or on an up-line is a far better way to determine the skill of a pilot than a snaproll in a down-line or at the top of a loop.

Electrics turn even bigger props at even lower RPM with even more bottom end grunt, but like everything there's a happy medium and you just can't keep halving the rpm and doubling the torque without introducing new problems.

Two-strokes in a heli are a whole different ball game because they're always up on the pipe, running in their sweet spot waiting for the command to dump their available torque into the gearbox. A geared, constant rpm 2-stroke in an F3A ship with a variable pitch prop would probably work well but it would be a whole new sound for the judges to get used to ???