A 170 cdi newbie here with a couple of questions. I purchased the 170 cdi off of ebay, a Hong Kong hobby shop with very good feedback.
I have the engine on my plane a Fliton Element 170. I had it at the field on Saturday to do the first run and to set the needles. I have read and reread Troy Newmans articles on the glow 170 version and the cdi 170 version and I'm aware of the relationship between the regulator and the hs needle. I had trouble getting the engine to run right, it had a good idle 2100 rpm, it would not drop off in rpm or surge so I felt like the regulator was set very close. The hs needle was initilly set to 2 turns out. I would slowly advance the throttle and it would start to stumble (miss) at 1/2 throttle. Finally after many adjustments leaning the hs needle I got it so that would take throttle without a miss. On the finalle run at full throtthe the engine suddenly shut down without warning. I thought the engine had siezed but it still turned freely. I was tired and bummed by now so packed up and went home and reread the owners manual and Troy Newmans articles again. Today I checked the spark plug gap its .015 and the valve clearance both are .002. I strap the airplane down on a table and point into the wind and start it up. I let it warm up and advance the throttle slowly to full and no stumble. Back to idle and its good at 2000 to 2100 and then advance again briefly to full again it is good no problems now back to idle for a couple of seconds and shut the engine down. Five or so minutes later I crank it up it idles fine, I advance the throttle and this time I have a major miss starting at half throttle so I shut the engine down and let it cool off for about 35 minutes. I restart and its ok except 1 small stumble. Is the engine over heating causing my problems (I think this is whats happening) or is there a problem with the motor? The hs needle is now at11/4 out and the regulator is flush at the 4/10 oclock posistion. Fuel is Curtis Youngblood 30% heli with an APC 19/11 prop. The field elevation here is 3300 asl.
Thanks
Mark

Mark,

Did you follow the instructions and run a tank or two through the engine before advancing the throttle above half?

The engine needs to run for a while before you open it up. Try that and then go back to your testing.

Arch

I don't recall reading that but I can sure do it.
Thanks
Mark

Hello Mark,

Two things,

As Arch mentioned before, let it run for one tank at 1 1/2 or 1 3/4 HS needle setting. Do not mess with the regulator yet.
Second and very important, take that 19x11 off until you have at least 40 flights, go with a 17x13, not 18.1 x12 or any other thing you might hear, 17x13 APC, your problem right now is the prop nothing else. This is not in the manual, but that prop is intended for well broken in engines.

Just by doing that the engine should run fine, the idle at 2000 is ok for the new engine, later (after 10 flights) you can go down to 1500, you can do it know, but it will stress the engine a little as everything is tight and there's not much power at idle.

This is the way I have done it in all my 170 and they are very smooth. One note, if the engine is too rich it might misfire once in a while and that is normal.

Good luck and let us know how it goes.

Regards

Alejandro

Thanks for the advise, I dont have a 17X13. What do you think about cutting a apc 19X11 down to 17 to 17,5"
Mark

Mark,

I wouldn't cut down the 19X11. Pick up an 18.1X10 or something to get some time on the engine. Eventually you'll like the 19X11, but let the engine get some time first.

Arch

Cutting the prop will not give you the performance in the air that you might want, not loading the engine excessively is the most important thing here, try to get the prop, the idea is to get a smaller diameter propeller to reduce the torque the engine needs to produce when is too tight, 17x12 will do too, but after 10 flights it will not be enough, getting the 17x13 worth it.

Best regards.

Thanks guys. I have a 17X13, 18X10 and 18X12 on order now.
Mark

Mark,

The most important thing is to lightly load the engine at first and let everything "seat." Once you get some time on it put the larger props on and you'll have no problems. Sounds like you've just got a very tight engine, which is a good thing. You will be very happy once you get this thing broken in,

Arch

Has anyone tried the APC 18.5 x 12 WPN prop on the YS170 CDI? What other props work well with this engine aside from the 19 x 11? And are 18 x 11 WPNs still available? Cental Hobbies doesn't have them listed on their website. Thanks.

Yes, they are still available. Central's website isn't always totally current. Easiest to email or call them to verify.

I ran the 18.5X12WPN and I personally didn't like it. I know some people love it, but with my Black Magic being very draggy it seemed exceptionally slow to me. There are some people though that are running it and love it, so it is definitely a viable prop on this engine,

Arch

Jayjay,

If Central don't have them, you can order directly from APC, that's what I have been doing on all of my WPN props.

I felt the 18x11 wpn don't have enough pitch, and have been using the repitched 18x11.7 for quite awhile. As for the 18.5x12 wpn, I agreed with Arch it's a bit draggy. I been shortening it down to 18x12 and reshape the tip to make noise, and I do like that prop. About 7,350 to 7,400 on CP heli 30%. However, Onda used the stock 18.5x12wpn at the WC.

Adrian

Hi Adrian,

Thanks for the info. I will give Central Hobbies a call.


Jayjay

Hello Jayjayneri,

I haven't tried the 18.5x12WPN, I'm ordering it today, but Yamada told me at the worlds, that was the new prop APC was working on for the 170 CDI and Onda was using it. It's a matter of taste, you have to try several props to find which one you like.

The 18.5 12 is used primarily for noise issues.
Of the glow models at the worlds,I think Team Japans engines were the quietest.
12 pitch seems to be the magic number for that.
In my testing, However, the midrange on the 12 pitch wpn has a step feel like getting on the pipe with a two stroke and it can get fast on you quick if your not on top of it.
The 11-11.5 pitch props in the 19-19.5 range can be made as quiet and work the best overall IMHO most constant curve and better brake and speed control
particularly if you Carbon the prop and stiffen it up ( a little trick I learned from Lockhart
Your better off extending the blade for noise reduction and sticking with the 11-11.5 pitch range.
I`m not a fan of the WPN series of blades except for the 10 pitch when I was running the YS1.6
Bryan

Hello,
a tecnical question...

On the connecting Rod of the 170 cdi , Is there bearing or not ?
thx!

Thanks for all the advice guys. I just got 5 different prop sizes to try. Now, all I need is the engine. LOL

I'm all for advancing the state of the art, but why not go with a gas engine? The fuel is cheap and available everywhere. Has anyone given the Evolution 26cc or Mark 1.80G gasser a try in a pattern plane? The YS's seem to be all the rage for pattern, but personally I've seen a lot of guys fight the things more than I care to do.

Take a look at the new thread on the Syssa 30cc gas engine. I'm getting one to try out.

Voldos,

There is no bearings no the conecting rod.

Sellaplane,

The YS engines are supercharged, and no internal combustion engine of that displacement has the torque at low or medium RPM's as the YS, ussually the YS 170 is an expensive engine that goes in much more expensive airframes, so fuel cost is not an issue if you can afford the equipment, and power to weight, no gas engine come close to the YS.

Regards

True enough, but we have just found that there is one that weighs less than the YS 170 CDI and before being broken in, seems to be stronger than 2 stroke OS 140, and on a par or a little better than the 160. Some of us are going to see what it will do in the air. The Syssa SAP 180 with the ignition module weighs something like 35 oz. I don't have the exact number yet. The YS CDI is around 38 oz, so it's coming in a little under that, which is nice.

I don't think anyone has any illusions that a 1.8 ci gas engine can match the YS 170. The fuel payload will be a little lighter with gas as well, and I for one certainly don't mind saving the money, if this engine proves out. So what this really represents in my mind is an upgrade from 2 cycle glow. It will probably perform best if the unfueled weight is kept under 10 1/2 lbs, just a guess at this point. Time will tell.

This has been debated ad-infinitum. Gas engines are too heavy and don't have the power-to-weight ratio needed for F3A. With a weight limit of 10 lbs, it's difficult to use gas. The YS behaves very well once you get the hang of it. The trouble is, you have to spend the time to get the hang of it :-). Once dialed in, it's the most reliable engine out there not just for F3A but also general sport flying. It can run on zero nitro as well, as long as you use a smaller prop. With zero nitro and 8% oil, the fuel is not that expensive. Add Nitro and you have an incredible powerhouse.

Atul

javascript:void(AddText('','_image/s1.gif'))
[/quote]

Gas engines are too heavy and don't have the power-to-weight ratio needed for F3A. With a weight limit of 10 lbs, it's difficult to use gas.

[/quote]


Wait a minute, since when do they lower the weight limit to 10 lbs? ...

Atul, take a look at what Matt posted on the Syssa engine thread. The weight of their 30cc, with ignition module is less than a YS CDI, a slight bit more than an OS 160, with what appears to be equivilent or slightly better power as compared to an OS 160. This is with a brand new, unbroken in gas engine. We got some very respectable RPM and static thrust numbers this past Saturday. For example, it turns an 17x12 APC at 8200 after warming up (almost 8300 when cool). Static thrust was 19.5 lbs. That's with a pipe of course, and it appears to be well mannered on the pipe too. We got some very good results with a few other props, but I'm not going to write my entire K Factor article on RCU!

This engine has potential. It will take some test flying to see how well it works out for our application. We may discover that it will need some mods for a longer stroke maybe different exhaust timing, but it looks usable for testing right now, as is. Nothing ventured, nothing gained!

Ed: yes, I saw the post about the Syssa engine. Interesting - but it does need development. Gas engines tend to run quite hot (read about the SAITO FG-36 : The engine runs considerably hotter than Glo). The nitro in the YS helps significantly with cooling. Gas is good, but it's meant for bigger planes I guess!

atul