U Can Do 3D
 

oops, was trying to be witty about the pitfalls of the YS, not bash. went back and re-read it, can see where you got the notion.
I like my YS's, gobs of brute power. But after dealing with them since 1994 until now, I <love> the new Saito - none of the hassles, and very close to the same power - If I'm worried about tank placement a pump/regulator solves the problem, but I've never had an issue with it. As for your not dealing with any maintenance issues, there seems to be two camps of YS owners- those than run perfectly from the get go and never have a problem, and those that have problems from day one and never ever run right. I've owned both types, and kept the one that runs great, had it since 1995, and all I've ever had to do with it is replace the diaphragm about every two years - that motor probably has had more than 400 gallons of glow fuel through it, anwhere from 10-30% nitro, I'll never sell the motor, and I'll always have a plane to put it in, just not the UCD, <personally> I dont think its as good a match as the Saito 100 for <this> application. My only real complaint about the YS are the care and feeding issues with the pressurized fuel system and the parts involved to make it pressurized - important things for a potential YS customer to know about, the average RC enthusiast is not going to be able to work on this motor without some experienced help.
oh, just for giggles i put <my> YS 120/w aftermarket muffler, and <my> Saito 100/w included (altho heavy) muffler on the scale. saito - 25oz, YS 38oz, you're right, its not a full pound, only 13 ounces difference.

I'm not putting down the YS, just extending my personal experiences for others to read. One should know everything there is to know before plunking down hard earned cash. Sorry if I offended you.

U Can Do 3D
 

Desertrat,
No hard feelings mate, I suppose I got a bit defensive there myself, just tired of hearing all the bad rap on YS, especially since much of it (not in your case though) comes from the modelers who are to lazy and/or ignorant to read the instructions that come with the engine. I flew a 6.25 lbs Extase powered by a YS91AC (the one I'm holding here to the left) beforoe the UCD. That's why, when I took one look at the size of the UCD, and knowing it would come in at 8 lbs or so, I just knew that the YS91/Saito100 size power plant wouldn't tickle my fancy he he.
DKjens

Question
 

DKjens: What is a Extase, and where do you buy them? Thanks Capt,n :)

U Can Do 3D
 

Capt,
The Extase is made in the Check Republic by S2G. It's imported by PlanePower in RI. You can do a search here on RCU and find it, Mike James in Anchorage did a write up on the plane. I found that it had a lighter feal to it than the UCD, Walls were very abrupt and without any wiggle. It lacks in rudder authority though, so flat spins an hovering is not as easy as with the UCD. It's also more expensive than the UCD, but not by very much (price is $220.00 I think). It does better waterfalls than the UCD, I was doing them about 10' over the runway, and ended up needing 11' he he, but it's repairable.
DKjens

U Can Do 3D
 

Dkjens: Would adding more area to rudder help the flatspins ect? Thanks Capt :)

U Can Do 3D
 

Capt'n: Adding more rudder is what I'm going to do when rebuilding this plane.
DKjens

U Can Do 3D
 

WHAT size prop do u reccomend on the u-can do with a saito 100.. now in using a apc 13x4 w seems to be ok.. but not much experence with 3d flying yet.. just getting into it..
is there any good articles out there on 3d flying how to ect..

thanks olmanbruce

prop
 

I have a 13x6 in my OS 70, I think you need a bigger prop on that 100, I'll say 15x6 - 15x8 - 16x4

U Can Do 3D
 

I'm using a 15x6 Zinger. It works pretty well , I'd like to try a 16X4, just haven't ordered one yet. I'm surprised you haven't thrown a rod on the 100 using that small of a prop. Good luck.

U Can Do 3D
 

thanks for the info.. will pick up a 15x6 and 15x8 tomorrow..
never gave it a thought on possible throwing a rod..
olmanbruce.

U Can Do 3D
 

In response to post #517, regarding the strong pitch to the belly, you "could" try increasing the wing incidence. If your really observant, a 1/8" spacer placed between the wing TE and the wing saddle will effect a change. If your not so observant, make it a 1/4" spacer just for "experiment" sake. 1/4" should effect a serious change, as I'm sure it is several degrees. However, be prepared for the plane to pitch up when you take off, because it will need down trim of the elevator.

OR, use the mix function on your radio. Make rudder the master, and elevator the slave. Add a percentage of elevator that goes the correct direction for your radio. Check the other side of rudder.

If you have the Futaba 9C do the following: Open the mix menu and make the proper selections. Leave the menu open. Predetermine which direction of "dial" give the proper elevator mix response. Fly the plane in K.E. and use the dial to induce the correct mix. Fly many passess, and ensure it is the proper amount. This saves many landings and small changes. I do this with my pattern plane. The mix menus are easy to access in flight.
Best Regards,
Jim Woodward

U Can Do 3D
 

Summary of suggestions (post # 1)

I'm fairly new at this. I saw a UCD at our local field and had to get one - my third plane in the year I've been at it (fourth if you count the one I destroyed/replaced - my first mistake with dual rates). When the shipments finally started up again, I was lucky enough there was one in my LHS that hadn't been claimed so I snatched it up. Had one night to check things out and had to go on a trip and haven't had a chance to start putting it together yet. Someone in the shop told me about RCU and I've been reading the threads for the last three nights! Here's what I've gathered:

- Reinforce the gear attachment area
- Reinforce the wing dowel hole area
- Fuel proof the firewall (and more?)(epoxy?)
- Upgrade the pushrods
- Check for broken ribs/other damage
- Get a different tail wheel assy
- Possibly use different hinges (might want to really do this since I've never done CA hinges)
- It seems the favored engines are OS FS-91 II and the Saito 100 (except for DKjens who would put a small-block Chevy on it if he could make it work! lol)
- Check for right thrust built into the firewall, if none add washers
- Use a remote glow igniter

Any other big tips?



A few questions:

Do you need to tap the holes in the engine mount or can you just drill holes and mount w/bolts?

Do you leave the string inside the wing after installing the aileron servos in case you need to replace them?

I've seen that people have glued the belly pan right onto the covering on the wing, even put a fillet of epoxy along the edges. This seems to rely on the covering a lot. Any danger of the covering pulling away and letting the belly pan flap in the breeze? Would it be worth it to trim some covering away so you can epoxy the pan right to the balsa sheeting?

If you use carbon fiber pushrods, can you just cut them to size with a cutoff wheel or do you need a special tool (so to speak)?

U Can Do 3D
 

Hrkdrv,

I think that the YS 91 or Saito 100 are what are most favored for sea level. My nod would go to the YS for enabling you to mount the fuel tank back at the CG. You can do this with the Saito if you put a Cline regulator set up on. As far as all the others, fuelproof the inside of the firewall around the hole at least and do all the others. I would also go with nylon 1/4-20 bolts for the gear.

Mount the engine however you are comfortable with. Through bolts with nuts are better, IMO than the tapped holes.

Go ahead and pull the strings completely out. If you need to pull a servo, tie a string to the lead before you pull it out so you can get it back in. Make sure you secure your extensions with heat shrink or similar.

I peeled covering up for my belly pan, but you honestly don't have to. There are no real flight loads there.

For CF pushrods, I use a Dremel cutoff and wear a dust mask. Cut lightly around the rod until you are through instead of across in one cut.

Hope this helps you,

Dale

U Can Do 3D
 

guys,, thanks for the info.. saiot 100 runs better with the wright prop and reset the low idle, pinch off fuel like to carb when fueling.. much better..., starts every time..
thanks again olmanbruce

Uggghhh
 

Which engine?!?!?!?

YS FZ 91?

OS FS 91 II w/pump?

Saito 100?

The YS has 2.0 hp but it's 200 grams heavier than the Saito.....help.

Re: Uggghhh
 

This has been debated a lot already. I think you'll get a good performer with any of these. They all have pros and cons and it comes down to personal preference and what is important to you. I have a YS91FZ on mine and love it. Lots of other people love the Saitos. You'll get a different opinion from everyone. At least from looking at previous posts, the leading choices seem to be the Saito 100 and the YS91FZ.

Chris

U Can Do 3D
 

I love the Saito 100s performance it gives my UCD. But the bearings does not seem to last long. I have a month old Saito that has gone thru 6 gallons and it's already off to horizon for a bearing replacement. I use 30 drops of after run oil every day of usage. But I guess torq rolling and hovering 8 minutes out of 10 minute flight time would kill any engine quickly.

U Can Do 3D
 

My only issue with the Saito is the fuel draw. If you put the tank back at the CG, put a Cline regulator on it or go with the YS. IMO, the YS is more of a powerhouse than the Saito. It also weighs 5 - 6oz more. It ends up that you should choose what you are comfortable with. There is no real price difference, but I think that you still have to add the Cline for the Saito. I have a YS 120 on mine because I fly at 5200' otherwise I would have used the YS 91.

Dale

U Can Do 3D
 

im FLYING ONE NOW.. LOVE IT HAVE A SAITO 100 ON IT..
ALSO HAVE A NEW ONE IN THE BOX JUST IN CASE,, HAHA !!!

ITS A NICE PLANE.. U- CAN-DO

OLMANBRUCE

Thanks for all the replies
 

Since this is my first foray into 4-strokes it's a tough choice. The guys at my local club are hip on YS and Saito for 4-strokes (OS for 2-strokes). You're right about the price; they're all within about $20 of each other.

I've read some posts about pumped engines causing problems w/cracked fuel tanks. Is this prevalent or a fluke occurence? Easily solved with a more elastic/higher quality tank? Is a cline regulator a type of pump? Is the YS "supercharger" also a type of pump? After this, no more dumb questions.....thanks!

U Can Do 3D
 

Hrkdrivr,

The YS pressurizes the fuel tank, so a stout tank - no Dubros or Sullivans - is required. The tank that comes with the UCD is pretty stout and I am using it stock with my YS120. If you have a concern, wrap filament strapping tape around the front, middle and back of the tank and put a nylon zip tie around the stopper neck and pull it tight once you have the stopper in place.

As far as the Cline, it works pretty much like the YS system only it uses carb suction to run the diaphragm instead of a pressure pulse like the YS. It pressurizes the fuel tank through a one way valve from the exhaust - on a 4 stroke and from the crankcase on a 2 stroke. If you go to http://www.billsroom.com/pcfs/fuelsysdesc.htm it will explain better than I am.

The YS is kind of supercharged because it uses the down-stroke of the piston to pressurize the fuel charge into the intake through a disk valve on the back plate. The air chamber on the 91 is to smooth the impulses for better operation.

Needless to say, with either system, you want a good tank that is not elastic.

Dale

Saito 1.80 powered UCANDO
 

There is no such thing as too much power so I installed a Saito 1.80 single cylinder in my UCANDO. Yes, I've added a few ounces to the tail, but the accelleration out of a hover has to be seen to be believed! She actually will hover a few clicks off idle with a 16x8 prop.

She has unlimited vertical. I have literally flown her straight up until I couldnt hear the motor anymore and lost sight of the plane. I cut the motor back to an idle and applied full up elevator and left aileron until I could see her again... it took about 15 seconds :stupid: .

I fly off of a grass runway, so I beefed up the weak landing gear and so far... it has been working great!

weight
 

Hay Searcher. How much does your plane weigh ready to fly with the 1.80 engine? does your plane still float in on landing or do you have to land it a little hotter now?

U Can Do 3D
 

Man that sounds like an unbelievable combo. Saito 180, and the UCD. I am just glad, I don't live anywhere near your flying field to take the plane up so high you can't even hear it anymore. Thats more than I am willing to do.

U Can Do 3D
 

With Saito 180, it's more like a tractor rocket w/ oversized control fins!!