Anyone else besides me having troube uploading photos to threads?

I often wondered about the gearbox or variable
Pitch prop as well, on IC engine . This would get rid
Of low end issues

hello bjr_93tz
I think you stay on a prejudge comming from before the liberalization of the volume svept of the engine in 1996. after it is not the case 2T and 4T have quiet the same volume svept and if they turn the same prop at the same rpm they have got the same power and torque (it is only physics) I collect some measurements that all pepoles post on RC universe and french forum too or I made on RCGF and Webra and after caraterised some propellers in power Il plot some curves. I think there are very interesting

for the torque

for power :

sorry curves are in french, for your helps : reso = tuned pipe ; pot echapement = canister ; couple = torque ; puissance = power ; vitesse de rotation = RPM

the fuel for the YS engines is 30% of nitro.
for the webra 160aar : only 10% of nitro
and for the RCGF 32 : gasollin (french SP95) with 3% of oil.

these curves demonstrate one thing : there is not only one solution but a set of solution : I explain me : YS is a solution (a very expensive solution) but not the only one; 2T are not died and are good solution for beginners, electrics is an other solution (expensive too) and the future is probably gasoline as show the curves because costs are divided by 3 compared to YS or electrics and power is here !



stephane

DagTheElder
To me!

As you can read in this thread there is a lot of opinions and you wish some have been better substansiated. Anyway, you will find it opportuned for you to conclude this discutions as you are going away for a perid. You wish all the best for your participants in the thread.
You must humble thank everyone.

Hey you yeh you DagTheElder, have a nice holiday in the sun! (mumble)

Thank you DagTheElder

Hi Stephan,

Its great to see some factual data on the perfromance of these engines. I have a query though, in your data showing power is there really such a difference between the YS 170 DZ and the 170 CDi, as this is just an ignition change from glow to spark. The fundamental power of the engine should not change wheras your data shows a difference from example of nearly 1/2 hp at 7200 rpm. Was there some other difference between the test conditions?

Best wishes

Keith

hello Keith,

about measurement realized on YS engines : I take measurement of rpm that all members of the forum post on RC universe and on F3A.fr. it is interested to see that all measures was realized with APC propellers and it is more simple for me because it reduces drasticlly the number of prop to caracterize in power.for RCGF and webra I used my own measures because I have these engines at homre. after you must know one thing : when your engine runs a prop the power absorbed by the propeller is eqaul to the power provided by the engine, so if you measure the curve power of your prop it becomes easy to determinate the power of all engine just by knowing the dimension of the prop and its rpm. and you can write : where N is the RPM and D the prop diameter and gamma the power coefficient of the prop.
after in my case measurement have been done with a good weather and a temperature near 20°C, it is some classicals conditions.

the difference that you pointed at 7200rpm is justfied by the difference of the prop sized that they run at this RPM . the 170 cdi run a 20x10.5 and the 170 DZ only the 19x11. in the case of the 19x11 the 170cdi runs this at 7500-7600 rpm. 7700 in the case of CPLR engine.
it is interested to see that the 170DZ becomes very powerful up to 8000rpm it is for that reason that the best prop on this engine is the 17x12.
for 2T engines differences is not so great and and at low rpm (under 8000rpm) the advantage is for 2T such as OS or Webra. but in their case they arrived so early beacause the best prop for them is 18,1x11 which run at 7600 7700 rpm in fact 200 to 300 rpm faster than the ys170DZ.

stephane

PS : sorry for my english, I am no native english

Hello Stephane,

Hour 170CDI run about 8200 with the 19x11, we reduce the power at 7700 to pass noise check, at 8200 the engine is around 97dB, and the 20 x 10.5 runs on the 175 at about 7600, and as you stated 30% nitro. CPLR uses 25%nitro.

There is a power difference between the 170DZ and the 170CDI, if the CDI is converted it is almost the same, if the engine came as a CDI then it has the hyper piston wich increases the power, and you can get 500RPM more on the same prop, but the torque changes and the power curve is better, almost flat.

Very good graphs!

Regards

Hello Steph

Last year friend of mine saw CPLR testing a Yamada 200 on an Axiome. CPLR told him "it's a raging ".
As former french team member, any information about ?
Claude

excellent graphs Stephane. They bear out what can be seen in flight and measured.<div>
</div><div>I often wonder how it is possible for a RCGF 32 to rip a 30c Pilot RC Sbach 342 weighing 5.1Kg around the sky like a rag doll , have unlimited vertical and be able to snap roll and continue going vertical.</div><div>Yet install the same engine in a pattern plane and suddenly no one beleives it has the power.... strange</div>

Well, you add noise suppression for the exhaust and increase prop pitch hoping to maintain mid-range torque while reducing RPM, and there it goes.

The 3D guys are turning well over 9k RPM with 18x6 and 18x5.5 props![]

really, theres a Pilot RC SBach 30cc with RCGF spinning 20x8 JXF in the low 7's and it does not seem to held back much.<div>
</div><div>So much postulating about if it works, but the guys doing it seem to be having immense fun and keeping their petrol secrets to themselves</div>

If you want an answer to this, wouldn't it be a better idea to callYS and ask this question rather than ask it here? None of us can speak for another. It would be like you asking your dog if Ford is coming out with a new car next year.

Despite all the tech innovations with computers and internet, the old fashoined phone still works! Best of all, people still answer phone calls!

Yes Claude,
it is normal Christophe said always that

Muffling is one thing but the biggy IMO is: distance!
No problems hot dogging around close in... loads of power, but you get 150-75m out, 60degs either way. What looked like a big loop close in doesn't even register far out... F3A are manouvers are MASSIVE in comparison.
Thus the need for power. Loads of it!
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I'm happy of yours reaction and your remarks,

thank to A Periera for the measurement of its engine on 19x11 and 20x10,5 APC, and I confirm you that  your engine is very powerfull  but all I read on RC universe concerning the 170CDi and what I see is just bit lower.
In my oponion of Patern pilot is that the power of a good DZ or 2T OS or webra is enough to realized correctly (8 at each manoeuvre) a P11 or a P13 now for example. after it is possible to have more power it gives comfort during piloting but I remember me when I'm a biginner I have problems with to much power too.

Now I enjoy explore some ways which are not commun or evident for most of us. As Claude (papone) cheers me I speak you soon of my next  F3A plane  equipped with a RCGF 32. this plane is almost finish.

stephane

Ok, it seems I need to respond to a few comments. I don't ask YS or Rich for one simple reason, they won't tell you. PERIOD! If YS had a working gas engine coming soon, with the necessary cajones, they couldn't give away their current stock of glow fuel 175's, so it won't be available until the current supply of 175's were sold. Just like they do now, no 175s come out until the 170s were gone, no 170s until the 160s were sold. Unless you live in Japan, then YS will sell you whatever they have. Perhaps I have boxed myself in, so what, then I just won't fly pattern. If I don't enjoy it, I won't fly it, so again, no electric for me. And I refuse to pay the glow fuel cost, so no YS for me either unless they release a gas engine. Pattern is hardly my only R/C interest, if anything it is the passing interest, and if what I want is not going to be available, then I will find other interests. The basic question of this thread was about YS having a gas engine in development, not how stupid or short sighted I am for not flying electric, or the esoterics of whether one could be developed with the required power. It appears no gas engine is on the horizon for YS, so now I will go away and find a more suitable branch of the hobby such as classic pattern or IMAC.

Hi Dave,

When you start worrying too much about the cost of the hobby it's time to give it away... That has been my experience anyway.

Good luck in whatever you decide to do.

Cheers,
Jason.

Good for you Stephane. There is nothing wrong with the RCGF. Are you planning to use a piped set-up?

If yes, ES30G, ES40G or Mintor. The Mintor is only 4 1/2 ozs and is aluminum. The ES pipes are 3 ozs. Take your pick, they all work great. The Mintor is half the cost of ESComp. Header from Hatori should fit your 32cc

Dave,

Why not visit my threads on the SAP180HP, OS33GT and EF 78" Extra? They are all right here in the Pattern Forum. I have lots of info you may fnd useful

MTK and Steph, I am following your exploits closely.
I have been playing with a Spot On 120 fitted with a DLE 20 for the last year. The results are surprising because everyone keeps telling me that the 120AX I chose it really lugging the lumber around on that plane. They don't believe me when I tell them its a DLE 20. I even applied the DLE decal to my wing so that folk know its a DLE inside......but I always have to lift the hood to prove that I'm not lying.

I am going to experiment with a DLE 55 ignition because the timing advance of teh DLE 20 Ign is provong to be not well suited for pattern. The 55's ignition is apparently more linear.

I am also running a Weston UK aerobatic mini pipe but am considering switching to a full tuned pipe. The Mini pipe provide better mid range but seems to lack a bit of volume at high rpm. Sound is well within limits too.

Steph, your RCGF choice is superb I feel. I have elected to try a Mintor 33 on a Jet Legends Neptumo. I am saving for the ARF and should have it by March /April.

I'd love to see your results once you have it flying.
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Jason,

I cannot agree with your POV even though I respect you are entitled to it.

Cost of pattern is a major stumbling block. when you turn up at a Pattern event and from Novice to F3A everyone aspires to a full composite 2x2 and most have it, its pretty offputting that you have to compete against aircraft that fly much better than yyour little stik. Thats how it was for me when I started.

I looked around for viable alternatives to keep cost within reason because I have a family and other hobbies, the pie is divided. I feel very strongly about finding alternatives to the "norm" because the "norm" is skewed toward hgh cost options when there are lower cost options available.

Products lke Extreme Flights Vanquish 2x2
Eflite 160 electric motor
Rhino battery packs

all help to keep the sport affordable.

The reality of the situation is that folk choose between high cost potentially long life equipment or low cost shorter lifespan equipment. Thats their personal choice.

If good low cost options can be identified it van only make pattern stronger.
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In my opinion, going electric is the best option to keep the pattern cost down for the following reasons:

1. An electric motor (especially outer runner type) can last long long time
2. Since there are not much vibrations from motor, the airframe and onboard electronics will not wear out as fast. You can have a pattern ship around for years unless of course you want something different!
3. The cost per flight is very reasonable. A $100 10s pack can undergo at least 200 charge-discharge cycles, which is equal to $0.5 per flight. The charging cost depends on where you live and is around $0.05 in my area.

Timble,

If you are going for a Mintor, just make sure you can get support/repairst etc in your country, I friend of mine got the 170 and it was a nightmare from the start to the end, the engine never worked correctly, it is a very long and boring story. The engine looked completly man made with tolerances been to high.

I do not know if this is still the case with them, maybe they chaged, I do not know, but I think it it important to be warned.

Regards

DaveR,

Pattern is, for most of the people involved in this conversation, a discipline and a competetive endeavor. It is still a lot of fun for us, because if it weren't we would have done as you suggest by bagging it and moving along to some other aspect of R/C. We all started out competing with ourselves to improve the geometry of the maneuvers and the straightness of our lines and the centering of our rolls. We did this because we got tired of simply flying around and boring holes in the sky. Pattern is about flying with a plan in mind and putting the model where you want it in the sky and making it do what you want it to do no matter the wind conditions (granted, up to a point). As I like to say and as I am sure someone has said before, "Pattern puts the 'C' in Radio Control."

This takes a lot of practice and a lot of time. It is the perfect discipline for people who are content to see incremental progress over a long period of time, punctuated by episodes of banging their heads against a wall and then coming back for more. It is not for those who demand instant gratification. Yes, there are a few pattern prodigies who skipped a lot of this, but they comprise a microscopically tiny minority. The rest of us are somewhere along the continuum trying to improve our skills while juggling work and family obligations and figuring out how to finance our addiction.

After a while you're feeling pretty good about your flying and want to take it to the next level: competition. As I have found over the past couple of years, absolutely nothing makes me concentrate like flying in a competition. The best I have been able to replicate in practice is to fly at a field where mostly pattern guys hang out and have my mentor/coach (Anthony R) call the sequence for me with a very critical peanut gallery looking on. Or have somebody videotape the flight. Something to add some external pressure. This I first learned from Archie Stafford and Dave Lockhart, that you have to enjoy performing under pressure.

With regard to the propulsion system issue, a couple of years ago I was in the same boat as you: no glow, no electric, period! Which meant gas, so I did keyword searches on RCU and elsewhere to see what the options were for a pattern gasser. After much poking about, I found that MTK (MattK) had done a lot of experimenting with all manner of 2-stroke gassers and was currently working with the new American-made gasser, the Syssa (SAP) 180. I tagged along and got all kinds of help from Matt while setting up a Focus II with a soft engine mount (RCU thread also by Matt) and a ES pipe. We did a lot of experimenting with the pipe tuning, pipe coupling material, and props... wow, a lot of props, with some very impressive custom hybrids hand-made by Matt himself. If you do as Matt suggests and search the various pattern gasser options he suggested, you will find a "SAP 180 Cookbook" that we put together as a result of that effort.

I flew the crap out of that Focus II/SAP 180. It worked very well for me at the time because what I needed was something that didn't cost a lot up front (it ended up being a bit over $2100) and was also cheap to fly. I was flying in a lower class anyway, and needed a lot of stick time just to learn the basic stuff. Then we started having problems with the front bearing seal, to the point that I developed a crack in the crankcase near the front bearing. Syssa repaired it quickly and got it back to me, but then at a pattern contest later Matt and I discovered a leaking bearing seal in his engine. We struggled some more with the front bearing issue (I had another leak in my second SAP) with the manufacturer, who subsequently changed the bearing specs, but by then it was too much for me. I wanted simply to fly and have absolutely minimal maintenance issues to deal with. I live in a condominium and have no workshop except the den that my very understanding wife lets me invade on occasion, and a small outside deck where many times I have worked on my pattern models in sub-freezing temperatures. Look through the photos on the SAP thread and you will see I constructed the pipe tunnel for the Focus II on my deck when the temps were in the 20's. MattK has made it his mission in pattern to come up with a viable gasser solution, but as I applaud his perseverance I had to move on.

At long last, having seen the performance of electrics and having seen some very good fliers (specifically, Arch) switch from glow to electric, I decided to give it a try. I have not been disappointed, for all the many reasons stated earlier.

What I discovered is that pattern is not about the propulsion system. It is about maximizing quality flying time and minimizing maintenance issues related to vibration, mostly, and airplane damage or loss due to deadsticks. The "soul" of pattern is in the flying, not in the equipment. I find that now I do a lot more flying and a lot less maintenance and worrying. It is much easier to concentrate when you have absolutely no doubt that after the next stall turn the motor will still be running.

I know this has been lengthy, but I offer it with all due respect as one who has been in a similar position. I don't know anything about you and your length of time in the hobby or your level of experience/accomplishments in pattern or other facets of R/C.

With best regards and wishes for success in your quest,

Timble,

From earlier posts I think you've had the Mintor 33 for quite a while. What's the story with it?

I opted for their 38cc and was disappointed in the overall performance. Not a match for my SAP180's let alone the OS33.

Based on what I've seen so far in my gasoline endeavors, a properly designed 35cc gas engine meaning,
1-proper porting to respond to broad tuning,
2- useful compression ratio,
3- useful Bore to Stroke ratio,
4- light weight,
5- rear exhaust,
6- a walbro or similar with a mid range adjustment,
7- rear intake,
8- and a single prop nut
would be a good ticket for a 2 stroke. Keep all your leaf blowers and such for the YS Petrol 4 stroke.....Of course it doesn't exist today excepting for the PTE36 which I hear, doesn't have several of my perceived requirements