seanychen

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Johnylightning,

How fast is your 120 revving the 16x4W? How is the throttle response? Is spooling up instantaneous?

Johnnylightning

seanychen,

I haven't tached it yet, but prior to this plane, I always ran a 15x8 on it and I thought it ran fine. Well, needless to say, the 16x4W woke it right up. Throtle response is SUPER PRONTO! I wish you could see my verticals! I love to see the sun reflect off of this prop, it looks like a plate. Oh, and it pulls the stick out of a decending hover RIGHT NOW!!!!

seanychen

My Feedback: (4)

Wow, I have a Saito 100, and I tried the 16x4W on the Saito 100, the spool up time is about 0.5 second.. slow to say the least. Hmm, if 120 spools up the 16x4W instantaneously, then I ought to seriously consider it.

Johnnylightning

seanychen,
I'm glad you've replied w/ this info. I've got a UCD on back-order and I was thinking of this momo/prop config. I've read the thread and it seems that everyone is flying this same setup. What other prop would you recomend for the 100. Or do you think I should use my 120 on the UCD?

seanychen

My Feedback: (4)

I am using Saito 100 on my UCD with 15x6 APC. It flies pretty well. It hovers at exactly half throttle, and pull-out is about 1/2 g vertically. The plane weighs 7 lb, and CG balance is at 5.6" behind leading edge. The Saito 100 swings the APC 15x6 @ 9500 rpm on 10% nitro fuel. The throttle response is about 0.3 second from idle to full on this prop, with throttle servo @ 0.2 sec/60 deg. With this slight throttle response delay, correction bursts while hovering can become jerky.

It spools up the Pro Zinger 15x6 quicker, as fast as the throttle servo would go. I hope to fly on the Pro Zinger this weekend. I will let you know how it goes.

I might get the Zinger 16x5 in the future if I feel the need for more thrust.

I tried the 16x4W on the Saito 100. It would peak at about 9100 on 10% fuel, but it would not idle well, because it's too heavy. Also, the spool up is about 0.5 second. You might need very high nitro fuel to spool and idle this prop well.

As far as power, I think the Saito 100 is more than enough for UCD. The more important factor is to balance the plane at about 6" behind LE. I have the 5-cell NiMH right in front of the trailing edge, 3 MG servos at the tail, a Sullivan tail wheel assembly, and the 20-oz Saito 100 up front, but it still not quite 6" CG. So, if you were to go with a 120, you gotta put the battery pack under the stab. A 3-oz battery pack at the tail can offset about 9 oz of nose weight, since the tail moment is about 3 times the distance from CG to the engine. The lightest 120 would be the Saito 120S @ 28 oz. With this enigine, you may have hope of balancing at 6" if you mount the battery at the tail.

Also, Saito 120S is a better choice for UCD because it's rear exhaust, so since the engine is mounted inverted, its muffler can go under into the exhaust tunnel. With side exhaust engines, the muffler comes out of the cowl on the left side, blowing right onto the 2 servos at the tail, as many of us have experienced.

Other minor factors: 120's may not fit into the cowl completely. My Saito 100's valve cover is about 1/4" away from the cowl bottom. So to put 120 in there, you may have to cut the cown bottom and expose the valve cover, not that it really matters.

seanychen

My Feedback: (4)

U can see

seanychen

My Feedback: (4)

...

CheeseWeasel

I'm flying the UCD with a YS 91FZ and it has plenty of punch... and tons of vertical.

I'm still running the engine rich since it is new, but even with that I can't imagine needing more power.

Seems like the perfect engine for this plane.

Bobby

Johnnylightning

seanychen,
thanks a mill for the super-detailed info and pics. My OS120III wieghs 32.5oz :disappoin , so I guess I'm gonna have to rule it out. Even though the pumped feature is very reliable and I'd be able to mount tank on the CG, there's no way in HELL that I'm gonna add x-tra weight.

CheeseWeasel,
I like the fact that the YS 91FZ is pumped. I'm also aware that YS produces some of the more powerfull 4-strokes avail, :devious: but the weight issue is still there. I've read the UCD3D thread several times. It seems that these 2 engines are the running choice. But I'm still confused

Johnnylightning

So far, it looks like i'm goin w/ the Saito 100.

seanychen

My Feedback: (4)

You can use the YS 91 or OS 120, but it will balance at 5" at best if no extra tail weight is added. But really, the Saito 100 will give you all the power you need if you use enough nitro and prop it right. For example, using the Zinger 16x5 @ 9000 rpm would give you over 2:1 thrust to weight ratio, and the throttle response shouldn't be too bad.

But Jonny, as far as adding extra weight, how come you can justify putting the OS 120 on the Ultra Stick 60, but can't justify the same for UCD, which is a larger plane? I don't see the consistency here. I am sure you can do something to UCD's tail to have "useful" weights back there. Support brace for stab comes to mind, since a few people have broken the stab due to its weak structure.

Johnnylightning

Good point, seanychen, but it seems that I'm always adding x-tra wgt. to my planes even when I've been able to shift things around fore & aft :cry: . I'd like to keep the UCD as light as possible (for a change) and it seems like if I go w/ the S100 and the setup you've hooked me up with, it'll give me what i'm looking for. I'm anxious to know how the Pro Zinger works out, but is'nt that too much pitch for hvr/TR?

sharkey

Hey Jhonny, Nice job on the mods for your stick.I also moved my servos aft with pull pull 4 the rudd.&ele. How much better does your stick fly with the extended control surfaces?Did you extend both rudd.&elev. with the two extra ailerons?How much does your stick weight now?Thanks

seanychen

My Feedback: (4)

I hovered with the 15x6 APC just fine, but I guess a 4" pitch prop would make it easier.

UCD doesn't torque roll that easily. You need to add aileron input. I think it's the wing. It doesn't roll all that well in general. The shape of aileron, wing, and that wing tip lends itself to non-rolling stability. Even full deflection on those large ailerons does only about 1.5 roll per second.

Johnnylightning

Thanx sharkey, even w/ all that gear in the tail, I still had to add 2-1/2 oz to the tail to get my desired CG, that engine is just too heavy . I weighed myself w/ and w/out the plane on a pretty acurate household scale and it seems as if the plane weighs approx 7.25lbs. , but it feels very light when it flys (CG maybe?) Anyway, before I added the extended surfaces, hovering was fine, especially w/elevator but, rudder control wasn't great. It still isn't fantastic but it has improved a little and normal flight has remained the same (I increased x-po too). Oh, inverted flats actually climb and now require less dn elev. but no waterfalls, no blenders & no KE..."never had it...never will". I've been thinking of moving back the firewall and simply eliminating all of that "dead weight", but I'm sick of messing w/ this thing. What would you do?

Seanychen, do you think it's worth it? By the way I watched a video (can't remember if it was Jason S. or Frank Noll Jr.) claims that in order to T/R involuntaraly the craft must be 100% vertical. But I can see what you mean, I saw Mecan's video and the UCD did seem to strugle.

sharkey

Johnny,I'm tired of fooling with mine also.I have the Saito 100 on mine so not much of a CG issue. Its a great Sunday flier and the crow feature is cool also.I just bought me a extreme 330 profile for the wild stuff.I'm trying too learn all the 3D maneuvers on my simulator and then take them too the field.You may want too try the Saito on your UCD,I'm pleased with mine.Where is your CG on your Stick?Mine is set per instructions. Thought I might move it back if it helps the flight characteristics.Thanks

Johnnylightning

Yeah, I've got a Diablotin Super FG on the way and a UCD3D on backorder, so I'll just keep on flyin' the stick the way that it's set up now.
Sharkey, I've got my CG on the trailing edge of the blue stripe on top of the wing. I havent physically measured it, but percentagewise it looks like about 40something%.

seanychen

My Feedback: (4)

A great way to get lots of power and move the CG aft is to get a 2 stroke and a lOOOOOOOOOng tuned pipe.

In my opinion, it's not really worth the effort modifying the planes into something drastically different from what it's designed for. I'd just get a plane w/ short nose moment, long tail moment, and lots of control surface. That way you are tail heavy to start with. Cap is such an airplane. The EZ 3D Cap would be great. Check out the following review:

http://www.rcairport.com/product_gui...44&kit_id=1049

Johnnylightning

Sometimes, if you use what you've already got, you can use that as a training tool to move onto something that exceeds the middle step. many times, w/ just a little effort you can achieve what you set out to do. Think I'd rather try this initially w/ a $180.00 than to risk a 25%+.

torqeroll

My Feedback: (13)

hey whats up johnny lightfoot who taught you that cool elevator pushrod set up???? maybe some bad ass flyer.

Johnnylightning

Hey Torkky, we on this weekend? How 'bout sum tail dippin" in the lake. Last one in buy's lunch! :drowning:

torqeroll

My Feedback: (13)

if i remember correctly you have allready been in the lake tail ,fuse, wings and everything else. HA,HA,HA thats why brents profile flys like a brick. sundays the day for new set up on the XL

Johnnylightning

O.K., so I guess I'll be buyin' lunch What'd you do to that devil plane, move the cg? BTW did you notice, we missed one of the best flyin' days today.

torqeroll

My Feedback: (13)

moved the c,g and new longer servo control arms for the elevator and rudder. maybe will flat spinn and elevator better?? and also moved gas tank closer to c,g. we are going to be bad ass mother fu_ _ ers very soon. maybe we allready are?????

Johnnylightning

Maybe you'll be/already are...I'm still waiting on the 1.80 for my UCD :tired: , so Ill let you take the spotlight.

P.S. Watch your fu_ _ in' language!