TailTwister

My Feedback: (1)

I'm starting to cover my Su-Do-Khoi 60 and have again second (or third or fourth) guessed my engine choice. I bought a YS91FZ (26.6 ounces plus 3 to 4 ounces of lead in the tail). I'm sure that will make the plane over 8 pounds, probably 8.5. If I switched to a Saito 100 (a click under 20 ounces), I'm estimating no lead at all and a sub 8 pound plane. What are the trade offs. I believe that the YS will out perform the Saito, but by how much? Either seem OK on a 15x6 or 16x4 prop, and at a weight difference of a half pound or more, is the YS really the better package here? I like having the pump (probably and ounce of it's weight), but what else have I gained with my half pound expense? My tank is set up like WGEFFON's. Either will fly on Wildcat YS 20/20 fuel. Is the YS91FZ better enough to warrant it's weight? I'm sure the plane will fly just fine with either, but why add half a pound if the engine performance doesn't warrant it? For all I know I'll find a half pound difference in thrust too, and that makes it an even swap. I might (or might not) change out the motor for an even swap. I would trade it out if the available thrust out weighted the difference in overall weight, to keep the plane lighter on the wing. So, it's an 8.5 pound plane with a YS91FZ or a slightly less than 8 pounder with a Saito 100? Common guys, straighten me out here. I got a headache now

Did I mention that I'm the adult A.D.D. poster child

Texas 3D

My Feedback: (16)

I have the Saito 100 on my Graupner Showflyer, and it is turning the Pro Zinger 15x6 at about 9200 rpm backed off on the rich side ! Plenty of power for that 7 lbs plane ! Out of a hover straight up to the moon. Only one flame out so far.
I have no experience with the YS 91 but would not change the Saito for the YS if it adds 1/2 lb to my airframe.
Just my $0.02

TailTwister

My Feedback: (1)

T3D- That's exactly the input I'm looking for.

I've heard of the 100 hovering a 10.5 pound plane. That sounds like plenty of pull for a Su-Do-Khoi. Does anybody have a similar experience? Anybody thinking otherwise?

outssider

My Feedback: (23)

TailTwister.....

first off....the saito 100 with muffler and washer and the 2 nuts weighs 21.3 - 21.5 oz range ....not 20 !!

secondly... If you put the ys91 in, rearange the setup of your electronics so that you don't add 3-4 oz to balance.(put servos in tail if necessary... or move the battery back)

thirdly....I would not consider the saito 100 if the total dry weight of the plane is 8 lb or more...(actually "I" wouldn't use the 100 if the weight was 7.5 or more).

Even though I love my saito the ys may be a better choice in this case !!.....but the decision is half the fun


Texas 3d.....
I sent you a second e-mail regarding your showflyer...you never answered

TailTwister

My Feedback: (1)

I could move the tail servos back, but not far enough to matter. They are aft of the CG on the plans, and another 6 inches back is about all I'd get. With the servos in stock placement and the battery as far aft as I can get it, I still need 3 to 4 ounces. Moving the servos would get about 1 ounce back, and be a lot of work. Even at 21.5 ounces the Saito is still about 8 to 9 ounces better (counting lead in the tail), but thanks for correcting my weight. I guess I saw the "without muffler" numbers. Why the heck do they do that? Can't advertizers just assume that we will be using the muffler and print that weight.

PaulSwany

My Feedback: (45)

I put a Super Tiger .90 in mine.... The CG looks pretty close without adding any weight... I haven't weighed personnally, but Super Tigre's site lists the motor at about 21 oz. I have a 14 x 6 prop on it and tacked it at 10,400 rpm.... I think it will be plenty....

Last I weighed it, I got around 7 1/2 lbs.

TailTwister

My Feedback: (1)

Yeah, I was going to get a 91FX with a Jett muffler (also about 22 or 23 ounces), but I want to give the 4 stroke thing a try this year. It looks like the YS 91 or Saito will give me really close to 10,000 RPM on a 15x6 APC. The 91FX (and most 2 stroke 90's) are happier with a 14x6 up around 10,000 to 11,000 RPM. I had hoped the YS would balance a bit easier, but it looks like it's lead to the rescue. In reality, I'm not sold on 4 strokes yet. I bought a Saito 72 and a YS91FZ after hearing all the good reports. They are both a real pain so far, but I'm still learning. They also need a bit more expensive fuel to really run well. Maybe I should look for a new 91FX to trade for (plus a few $$$ for a new muffler after all, the YS was $279.00). I had a 91FX with a Slimline muffler in my first Ultimate (8.5 pounds easy) and was not impressed. With a 15x6 on 10% Cool Power it took 99.5% power to hover, with no pull out to speak of. I had hoped the Jett muffler would get me another 800 to 1000 rpm. I don't think it would do much better than 10,000 on a 15x6 on it's best day, and transition wasn't great either. That's why I wanted to try a 4 stroke. The YS with the 15x5 inch prop, there should be right at 10,000 rpm with a better transition than the OS. I just want the thing to lose half a pound somewhere in the front. I can lose about 500 rpm on that prop and give up only the half pound of thrust that makes the deal a wash. If the Saito can keep up with the YS rpm for rpm (I guess I'm dreaming here) then the choice is obvious. Some have said that the YS91 is a match for most 120s, so I think the 100 will never keep up. On this wing, I'm sure that half a pound will make a difference. I just would hate to end up with an under-powered plane. I got a rep to protect!

TERMAGATOR

My Feedback: (2)

"there is no substitute"

TailTwister

My Feedback: (1)

Now Gator... Tell us how you really feel.

Texas 3D

My Feedback: (16)

Outsider, I am sorry, if I did not answered your email :disappoin ! I must have deleted it thinking that I did answer it :bananahea or maybe did not received it.
Sorry ! Won't happen again. I am normally pretty good about answering emails.
Please feel free to email me anytime back with the same questions about that good flying showflyer

outssider

My Feedback: (23)

texas.....


OK...here is my question...


I am not going to add weight to get this to balance no matter what it takes !! so... I want to know your thoughts about the balance (3 servos in the rear??) in the stock locations??.....also...that heavy push-rod for the rudder.. did you use it ?? it looks good but feels heavy. The review in rcunivers states that he added 6 oz of weight in the nose before he got acceptable flying from it ...

I have not done any preliminary balance checking yet but I will before i start cutting the covering off the servo locations in the rear of the fuse....

I'll take whatever information you can give me about the balancing of your showflyer

thanks.....outssider