Looking at some of the performance series kits form Great Planes ( Yak 54, CAP 232, Su-31 )

Got a couple of OS 160's for EF 74" yaks I am building, but get the feeling the 160 won't cut it on the heavier Yak and Sukhoi kits......have been contemplating brillellli 46's, but also thought about MOKI 180's

My question is going from OS 160 to Moki 180, am I really just adding weight , or noticeably increasing the power:weight ratio ? ( never run a moki 180 )

Also if they are a great choice would they fit inside the cowls of these kits ( I know the 180 is about 15 mm taller to the top of the head for a side mount )

Cheers


BIG S

I have had the Moki 1.80 and 2.10. Liked them both. The OS 160 is more available and stable company. The Moki has more power and sounds better IMO, better bark. Uses 0% nitro fuel, very fuel efficient. They are heavy but powerful. The low mixture dial moves, that's the only thing I didn't like. I think they have a clip for it now. The Moki is good for about 14 pounds max. Anything more and you need a 50cc gas engine.

I dont think the 180 has anymore power than the OS.The OS with a pump is powerfull,light and quite possibly more fuel efficient.The 160 has a minimal break-in period.Both are quality motors

Sorry but "I don't think" has no facts behind it. I have seen the numbers, the Moki will out turn the OS 160 every time. It's only by a few hundred RPM but it's a fact. Search the forums and you'll see the numbers that people turn with various prop's. There's no replacement for displacement.

Ground tach numbers never really seem to translate into much in the air.The motors may perform more evenly in flight.Torque curve has alot to do with it.Sure the Moki may have a slight advantage,but does it also not add a few ounces in weight?The person asked if there was a HUGE difference in power,and I would say no,thats all.
I have the 160 in the EF Yak,and it is not short on power (sea level)
On this clip I just changed fuel,and it is loading a bit on the low end,no lack of power though
http://media.putfile.com/Yak-54-video--3

Nitro Wing,

Thanks for posting that video of your Yak with an O.S. 160. Looks like fun. For Christmas the wife gave me a GP SU31 3D. I'm excited about it and trying to figure out the engine. The manual reports an expected flying weight of 13 - 15 lbs (although various publications including RC Flyer report they built at weights closer to 12 lbs). I'm debating between an O.S. 160 and trying to find a Moki 180 (found one on eBay). A guy at our flying field told me he thought the OS 1.60 may not give me as much vertical out of a hover that I would want. Could you tell me what the Yak weighed (approx) on the day you flew it? It seems to me you have plenty of power. Do you have a Perry pump installed? Thx.

I'd have to guess the weight,should be under 12 pounds.The 160 should handle a 13 pound monowing with ease.

I only have an 1100V 5 cell,stock tank.Yes Perry pump,this motor has never quit on me.
Use an APC 18X6W prop,it seems they have the most thrust.Moki is fine too,the 210 would be extra knarly

The way I see it, there is power and there is weight and there is wing area.
Get the most powerful engine your plane can handle and still have good wing loading. I have the GP YAK54. The wing area is a little low for the weight so I am going to put the OS1.60 in it to minimize wing loading. I have a Brillelli 46 in it now and it flies powerfull but a bit heavy. I do not want even the extra weight of the MOKI. Now the B46 I will put in my brand new GP Ultimat Bipe! The wing area is much greater (300 + sq inches more) than the YAK, and I believe it will handle the engine nicely.

It also depends on what type of flying you plan on doing. If you are doing stalled or near stalled 3D flight you want really light wing loading ( and a really powerful engine). If you are just sport flying or IMAC type stuff then the heavier engine is fine. The YAK tracks very straight lines with my Brillelli in it but it can get ugly in a stall.

I just watched that vid that I posted,yeah the motor was running ok,but my flight was..
I think I did a bunch of CG and throw adjustment after that..

Anyways,for the 2 motors in the GP Sukhoi,I just looked over the specs of that plane.The 160 will fly it with ease and have power in reserve.Dont do a gasser in it,its too small.

Let me tell you what is"fact". I built and flew the GP Sukhoi SU 31 3D with the OS 1.60 for the RC Universe review and I know for a fact that the OS 1.60 is more than plenty of power, that is here at sea level. I cant speak for higher elevations.

I have only flown it a few times but even brand new on Wildcat 10% fuel and with my Sukhoi weighing in at about 12.75 pounds there was no wanting for vertical authority. You absolutely do NOT need a gas engine on the plane that is going to push it up over 14 pounds. That would be a travesty. There is no need to add all that weight to the plane unless you just WANT to go gas. An even better engine might be a YS 1.40 sport or even better the YS 1.60DZ. That would really be the ultimate engine for the plane if you have the $$$$$.

Oh by the way, you can see the review,,, well,,,,,, in the Reviews section here at RCU. Go check it out. It was super windy so the video is just "ok" but you can see the engine doing its thing.

[link=http://www.rcuniverse.com/magazine/article_display.cfm?article_id=948]Link to RCU Review[/link]

Guys, thanks so much for the responses. Mike, actually, I want to put a glow engine in my SU31 3D. Glow engines are what I understand (I know little about gassers). I was thinking the Moki 180 was also glow - maybe I'm wrong on that. I've actually seen that video and it looks like fun. Did you install a Perry pump in that plane you reviewed? I'll go read your review, perhaps you mention it in there. I would prefer to go the OS route simply because IMHO I feel like service, etc. will be easier to come by. As for the airplane, I am looking to do fairly aggressive 3D maneuvers with it - once I think my flying skills will allow for it. Also, on a related topic, from my research, it would seem the Slimline Pitts style muffler would be the way to go. Agree with that thought? Thx again. I'm simply trying to do this right the 1st time.

I understood that from your original post, [8D] I just wanted to reiterate that the 1.60 is enough engine since there was some talk about what was needed to get the plane to perform well. The Moki 1.80 is a fuel guzzling glow engine. I did not use a pump on my 1.60. I only put a few flights on it but it did not seem to need a pump to get the fuel from the tank to the engine. I used a Bison Pitts muffler on mine and it worked great. I dont see why the slimline would not work just fine as well.

I thought the plane flew nicely. I think you will like it with the 1.60.

I had the OS 160 in the GP CAP 232 and it had great power. If the Moki weighs more and only turns a little more in rpms I wouldn't waste my time.
http://media.putfile.com/Kyle-3Ding-My-CAP-232

Ok I'm sold. The OS 1.60 it is (my wallet isn't fat enough for the YS 1.60DZ, but those look significant). Al, do you have a fuel pump on your 1.60 in the Cap 232? Mike reports not having one on the SU31 3D he reviewed (nice, comprehensive review by the way Mike. Man, I'll be referring to that during assembly over and over). Other threads speak to a Perry fuel pump really helping the O.S. 1.60 - particularly for 3D stuff; it seems like a non-weight issue while perhaps helping the engine?

It definitely could not hurt.

go with a cline if you really feel the need to pressure feed it

50/50 Here. I would go with the perry VP30. I have 3 OS 1.60FX at the moment two with out the pump. One on the pump. Also several others with and with out.
It's my understanding the Cline regulator only regulates the pressure the needles get and it relies on muffler pressure to get it to the regulator. Where as the VP30 actually sucks the fuel from the tank and pushes it to the needle valve with out muffler pressure. I would think that if you mount the tank further back on the CG for 3D stuff you would be better off with the VP30 as it would be more consistent as it does not depend on muffler pressure in the tank.
Pat

The Perry delivers, always,mine never sags,no matter how many G's I pull
On the Moki 180...There is a gasoline and a glow version.

The cline uses a check valve and is tapped into the back cover I had my tank 2 feet back just to test it I ran it for a few minutes shut it down and pulled tube of the regulator it shot fuel a good 10 feet
crankcase pressure can be as high as 9 lbs thats like YS pump pressure
the best thing about the cline is no chance of flooding inverted engines like the perry will do if the tank is too high which is the case in lots of inverted engines

Only time I had a problem was the time I installed the perry (not a perry problem, just didn't work well), maybe it was just me [&o] ,,I wouldn't put a pump unless I found a very good reason. Same goes for a glow driver BTW 3d is all I do

Don't try to solve a problem that doesn't exist.

PBT, I think you may have hit the salient point. I have been operating under the assumption (and yes, I know what assumption stands for), that for 3D stuff, the engine needs the pump. It sounds like you're telling me it doesn't need it at all. So, let me ask this...how hard is it to install a fuel pump after the fact? My definition of hard: Having to remove the fuel tank (the GP SU31 3D has some stuff in the way of the fuel tank and while I could do it, I want to avoid that if I can ). My definition of not hard: Removing the engine and then re-installing. I was planning to add the fuel pump now, during assembly, to avoid tearing things out later. But...maybe I should fly 1st without the pump and then decide? Sorry for all the ?, I simply have no experience with the fuel pumps. I've tried to find some pics, but no luck thus far. Again, I'm just trying to do this right, during the winter, while I have the time.

I might as well add my 2C worth since I have used a Cline/OS 1.60. The Cline is harder to install, specially if you have already mounted the engine, you have to drill & tap the back plate for a pressure tap. The Cline does work well even with a big 1.60. I used it in a 72" Goldberg Sukhoi @ 12 lbs. because the 20 Oz. tank was leaning even if just rolling the plane. I think the air bubble gets so big in a larger tank and the fuel demands of a 1.60 doesnt tolerate air in the line, just IMO. Also, I have flown the GP Yak/OS 1.60 a few times, even did a little 3-D, the 1.60 (new) seemed good enough w/o any fuel system. We had it set pretty rich but it still climbed vertical out of site & hovered for a little. I liked the way the GP Yak handled,KE all day long with little coupling. It would harrier with a little rock, but a little rudder & aileron locked it in.(APC 18X6W). The CG was 6.25", the tail surfaces were a little touchy so we dialed in some expo, it lands by itself, floats with the nose up just a little, no biggy though, hope my friend lets me fly it some more!

Some, but not all OS 1.60's run lean on a Bisson Pitts style muffler because the muffler is free breathing and provides insufficient back pressure to pressurize the fuel tank. This seems to be a borderline condition where certain 1.60's run well in warm weather but they go lean when the cool season comes and you find that you can't richen them no matter how far out you screw the needle valve.

I prefer to use the Perry VP-30 pump to take advantage of the increased power allowed by the low back pressure mufflers rather than crimping the muffler's exhaust tubes to create back pressure. The pump also allows you to place the fuel tank anywhere you want to.

The pictures show where I mounted Perry VP-30 pumps on a Giles and a Katana. One picture shows that the rear of the Giles' fuel tank extends well behind the wing tube. The remaining picture shows the O.S. 1.40 EFI pressure fitting that I use in my I.60 engines. The Perry pump comes with a little pressure fitting that you may find easier to install because you drill and tap the crankcase cover for it.

Something else to consider. If the cline system put's pressure into the fuel tank from the engine crank chase the fuel tank "could" pop. I seen it happen once on a guy who was using engine pressure to run a smoke system using a Dubro tank.
Pat

Rocketman, THANK YOU for the pics. Does the pump come with the mounting hardware? I figure it must. Is it difficult to "tap" the crankcase? Answer one question, get 2 more...