I have found myself an old school pattern kit (Lotus 5 designed by Peter Goldsmith) that I am hoping to purchase soon [8D]

The kit is designed for an RE 2 stroke, but due to the difficulty in obtaining one I am considering fitting a YS 110.

I assume that the YS will give better performance, but would like the opinion of some of you guys that may have first hand experience.

Thanks,

Mark.

Lets see, lotus V, is that the big one? the lotus 120 (about 6 foot long) or the old 60 sized one?

If it's the littley I'd say you're gonna have a tiger by the tail, if it's the big one I'd say you'd be spot on for a good sportsman ship.

The Lotus 5 is the 60 size one.

So, tiger by the tail.... that sounds like a good thing right?

YS 110 is a good choice. The power band is far different compared to the old 61 RE.

A YS 63 is probably closer to a typical 61RE than the YS 110, both in terms of performance and weight.

Magne

Huge weight difference; so plan on moving gear aft or adding weight to the tail (UGH!!). I would try to get a 2-stroke, myself.

sounds like a saito 100 or os90fx would be a good choice. Both would have enough for a 60 sized low drag FG model and probably with the stock set-up.

Keep an eye on E-Bay, I recently got a ''new in box'' Y.S. .61, and a NIB YS .45. Both rear exhast. When I get time to build the damn thing, the .45 is going in an MK Aurora 45. A Conquest in need of some TLC, is getting the .61.

The ys110 would have far more pwer than any of the old 61 re. but as stated above balance is an issue replacing a 2stoke with a 4 strock in the older aiplanes. Many of the SPA guys and others are streatching the planes to compensate for the extra nose weight. Jet might have what you need they are producing some of the strongest engines on the market at this time and part availability shouldn't be a problem.


gary

Thanks for all the replies. Mutch appreciated.

I have my eye on the YS 61's on ebay at the moment, and if the price is right one of those would be ideal, of course.

I'll let you know what happens.....

THose engines can not be compared really, I have all the models you talk about, the 61RE (OS) y have is really a beast on the 60 size with a good pipe, but the YS63 is way more powerfull than the OS61FX and it weights 200gr less, it sounds like any other bigger YS, the YS110 is a beast on the 100-110 side, weights as much as any 91 2 stroke, but the power......, but until is fully broken in it is not a simple engine to operate, the YS110S should be totally different if it behaves like the 63S.

If your airplane flies with a 61 you can put the YS63 and it will have power to spare, but if the aircraft was designed or intended for the OS61 Hanno for example I will go with the 110.

Maybe Mike McConville can ask Peter Goldsmith for you?

Regards

Well, one thing I am learning from this thread is is that the current crop of 4 stroke engines are way more powerful than I had thought. When I was first involved in RC, the general consensus was that you needed almost double the capcaity to get equivalent performance from a 4C.
Now, it seems that the current YS 4C engines compare power wise with an equivalent capacity 2C engine!!!

I hate to say it, but I'm swaying towards the 110. Not that that's a bad thing, but it is straying away from my plan of building one of the aircraft that I aspired to own when I first entered this hobby. The YS 110 just seems to be such a good engine.

Not sure if this helps, but i'm finishing off a 60 sized slingshot at the moment (Was a very similar to the Lotus V, but designed and flown by David McFarlane from Wollongong). I've put the YS110S in it and am about to test fly. I've been told that the YS91AC used to give the plane more than enough power (Was designed originally for the OS61 Hanno) so the YS110S should give it plenty (YS110FZ is the same size at the YS91AC, the YS110S is only about a 1 millimetre taller and the most powerfull).

Will see how the plane balances out, I think the engine is around 730grams

Since I'm in the midst of researching this sort of stuff I thought I'd pass along some "advertised" HorsePower specs I've come across...I think everyone will agree that a 2 cycle engine will just "Feel" different than a 4 cycle engine...But here is some specs if they help any??

A few Popular Old School engines that may have been used "Back in the Day"...(Not a complete list) :
YS 45FS/FR = 1.5HP
OS 61 RF-P (Not Hanno) = 1.85HP
YS 61R LS = 1.85HP
OS 61 RF-P "Hanno Special" = 2.0HP
YS 61R-AR = 2.0HP

New Technology Engines:
YS 63 = 1.6HP
OS 61 FX = 1.95HP
YS 110 = 2.1HP

Plus...fuel/prop combinations will obviously vary, how you tune the pipe, atmospheric conditions ect...Maybe too many variables to really be useful information?? (I'm full of useless info!! )


Anyhow...For what it's worth...

Ran the YS 60/61 RE, Webra 61RE and OS long stroke 61 RE (non-hanno) for about 15 years in the 80's and 90's. I am now running the YS63 in an Oxalis 50. Here's the skinny....the 60/61 2 strokes typically turned 12x12 APC's at around 9500 and produced very nice performance for models a bit larger than the Oxalis 50. We could manage as much as 800 square inches on those powerplants. The YS63 turns a 13x8 around 8400 on 20% nitro, and that quite a bit of power for the 5 lb Oxalis 50. The 110 4 stroke will turn a 15x10 at around 8500 give or take, on 20%. Different kind of output from the 4 strokes vs the 2 strokes mentioned here. One would need to determine how he needs to fly his model and then choose the appropriate powerplant. 2 strokes will produce more speed but not necessarily truck hauling power when needed for uplines and the like. And they are quite a bit fussier to set-up (pipe and fuel sensitive) than the 4 strokes. To me, the 110 will work exceedingly well on a 60 size pattern model of yesterday, especially the larger ones such as the Joker, Atlanta, Dash 5 etc., for example.

MattK

Do you have noise regulations on your field or why are you running 13x8? Everyone have told me that YS63 is happiest when topping 11krpm with a prop. 13x8 sound more like a prop for Saito 82. I am using 13x6 APC on YS 63.

Almost everywhere you go in the NE US, there is noise restriction. But noise or no noise, this is a great prop for this engine. The engine runs extremely well set-up as I have it. I don't know why "everyone has told you" that this engine needs to turn 11k. Why would you want to run a 4 stroke that fast anyway? A 13x6 works well also but in my opinion not as well as the 13x8. The Saito just doesn't have the output of the small YS

A few years ago I used to fly at the Sepulvida Basin in LA, and there were a bunch of guys there who liked to put YS .91's in 40 sized ARF Warbirds and tear up the sky flying in formation like a swarm of locusts. One of these guys told me that YS engines were overrated because he had trouble getting more than 11k on a 12x8.

There's one in every crowd. (Or in this case, about a dozen)

the 63's are best run up near the 10,000-11,00 range. This is the RPM the timing and the cam is set for. Yes it will get loaded harder and run, but it will increase the chance of something failing and when there is a failure or you run it lean...like running it out of fuel...The failure will be much more severe.

Its common on 4 stroke engines to be setup this way. The larger the displacement the lower the rpm. The smaller the displacement the higher the rpm.

Matt is a good motor guy, but I suspect the engine is working pretty hard at that rpm for a 63. If it was a 110-170 it would be better at that low rpm. Another issue is heat, I suspect knowing Matt he is flying the model at reduced power settings, and is not flipping and flopping around doing much if any 3D stuff. Since he has experience with engines and knows what is going on the chances or a problem are less, however the 63 is designed by the factor to run at about 10-11k and the noise produced by the 12 and 13" props at the 11k range is much lower than the 140-160-170 engine turning the 16-17-18 in props at 8500rpm

On 4 stroke engines the cam gear helps determine the timing. Its not like a 2 stroke. Example. an 11-7 will turn about 11k on the 63. a 12-7 will also turn about 11k on the 63. The 12" prop definitely has more pull than the 11" yet the engine ends up being limited by its timing. You want to run the engine in its happy place. For these small 4 strokes the higher rpms are the happy place. I just have way to much experience with them. Can you make them do other things yes...but you are taking the engine out of its envelope and when it comes to higher loads this means shorter life on the engine. As for the 91's and 110's pushing 11k is not good on them either they are happy back in the 9500 range. maybe just under 10k. The newer 110S seems to do well at 9200. The 120's around 8800, the 140's about 8400-8500. The 160-170's around 8100-8300 is the sweet spot. 4 strokes are for grunt. But they are designed around a certain range of performance.

Matt is a good friend of mine and I'm not condemning his use of the engine. But when and if it breaks Matt also doesn't go running to the manufacturer complaining about the failure. he knows what he is doing and its being run a bit too loaded for my taste. Again the timing is optimized for the rpm range intended. Just like your car. Picking a prop is like changing gears in the car. The engine wants to run at a given rpm for its power, and performance. Run it harder at a higher rpm and its not efficient, load it down lugging it going up a hill in 5th gear at 30mph well it doesn't like it as much. Yes it will do it....but not what the engineer designed it to do.

I have a 63 that has probably 500-600 flights on it over the course of several 4-5 years and it has never ever had anything done to it other than a new valve cover gasket and keep the tappet clearance set. I use the 12-8 or 12-9APC on 30% heli and have used this prop and fuel combo since it was new out of the box. Tried some others props and it was better for the model its in on the 12-8 and 12-9. RPMS are around 10,500

Troy Newman
Team YS

Thanks Troy for clearing things out for non believers 13x8 makes Matt a good customer so nothing wrong with that. I still argue that Saito 82 would make a little more power than YS 63 on same nitro content with 13x8 prop and it would be happy around 8500rpm. However it still sprays oil like hell and doesn't have a pump. If your are not running YS 63 on 11keur your missing some of the nicest rpm range of this engine.

Well my YS 63 is on Oxalys also