Flight 21

What??? Are you kidding me? "be ready for it or get lost?" What the heck is that supposed to mean? Reading between the lines it appears that you may be the one feeling threatened. If you are suggesting that glow/gas is dying you need to re-check your notes. The fact is that our hobby is becoming blessed with advancing technology in all areas - which is leading to new groups of flyers entering the industry. Electric and fuel alike are evolving (gas is getting smaller, for example). Powerplant options are growing in every direction - which is great for all of us! However, gas and glow will rule the scale and medium to large range birds forever because it more closely resembles the real thing. Period. You can start talking that "electrics will rule" garbage when electric planes are consistently winning Top Gun, Scalemasters, Joe Nall, etc. The best comparison I can make is: flying an electric is like driving a golf cart, where flying a glow/gas plane is like driving a V-8 muscle car. Electrics will never be able to deliver as similar experience to the real thing as fuel engines - regardless of whether you bolt your entire home theater system onto it. I'm tired of this junk about an electric airplane being as cool as glow/gas - that's a bunch of crap and everyone knows it (even you hardcore electric guys deep down inside). The electrics are growing primarily for one reason - they are practical. Also, for some reason fuel engines intimidate some people. And don't get me wrong I like the electric planes and have two myself.

The nice thing is that we now have options and they all have permanent places in our hobby. Everyone has good reasons why they choose their powerplant. Technology has come a long way and will continue to get even better - its a great time to be an RC airplane junkie...

frets24

My Feedback: (15)

You said it ,brother!!!

skillet92

To get back on subject (sorry I started down That path) I am turning a 15X6 Prop at about 9200-9300. It seems fast but not extremely so. What, to you guys that have tried other props, is a good scale prop. I am not looking for over kill just good, scale flight.

frets24

My Feedback: (15)

That's a lot of motor for a 60 size a/c already. The good part about a big motor is that you don't HAVE to run it full out and burn up the sky with scale supersonic flight. there's plenty of power there to get you out of a bind when you DO need it as long as you don't just firewall it all at once...then the torque can create a bigger problem than the one you were hoping to avoid.

That being said, the benchmark prop for the fs110a is a 15x8 @10,000 rpm(or 16x6 for the same rpm) At 1.8 HP with a max rated continuous rpmof 11,000, you could very easily run a 16x8 at 9500 or a 17x5 4 blade @9000. Scale blade size would be 18.75" If youv'e got the landing gear clearance for it, it would be cool. 4 blade props of that size start to get pricey though, and at 9000rpm a 5'' pitch prop only gives you 43mph so it would be very scale flying and easy to stall a wing on unco-ordinated turns or steep climbs.

jrod1019

[quote]ORIGINAL: frets24


That's a lot of motor for a 60 size a/c already. The good part about a big motor is that you don't HAVE to run it full out and burn up the sky with scale supersonic flight. there's plenty of power there to get you out of a bind when you DO need it as long as you don't just firewall it all at once...then the torque can create a bigger problem than the one you were hoping to avoid.

That being said, the benchmark prop for the fs110a is a 15x8 @10,000 rpm(or 16x6 for the same rpm) At 1.8 HP with a max rated continuous rpmof 11,000, you could very easily run a 16x8 at 9500 or a 17x5 4 blade @9000.




15x8 for an o.s. max fs110a at 10,000 r.p.m.? i dont think so, thats what u get out of a y.s. 110.

frets24

My Feedback: (15)

Just going from the factory specs and claims. This didn't sound unreasonable in that the OP claimed 10k+ with a 15x6 and detuned to 9400 on a relatively new(assumption) engine. Typicaly I see an increase of 700-900 rpm on any of my larger Saitos over the course of running the first 1-1 1/2 gal to fully break them in. Also, didn't set off any alarms when I read it since I get 9400 out of my 10 yr old Saito fa100 with a 14x8 MAS wood prop at flight setting and 9650-9700 absolute peak on Omega/Cool Power 15%.

maybe OS is stretching it a bit? I don't know, Don't bite my head off. Just doing the interpolation using the #'s given. I do know that the YS's that I see at our field have ridiculous power to cc/ci though.

AirWizard

My Feedback: (3)

Use a 8 pitch or larger prop

CorsairJock

My Feedback: (90)

Please edit that: make it BOLD and LARGE. It has been stated here before, but some just seem to skip over it.
This plane needs 8" pitch (or higher)

skillet92

Well I have a 15x7 and a 15x8 APC that I have for trails just wondered before I tried them. And as to the 110a turning a 15x8 10K well On the first tank following OS's break in instructions using a 15x6 APC i was hitting over 10K and after I finished the first tank I tuned it to turn around 94 and I it very rich. I have about a 1/2 gallon through it that has taken a while to do because on a typical 10 minute flight it burns mabye 6 ozs. It hand starts easy and has a great idle! I Believe that when it is broke in it has the ability to turn a 15x8 close to 10k

Mikecam

I run an apc 15x8 on my Saito 125 and it turns 8900 rpm. The 16x6 turns 9200. 16x6 is great for unlimited vertical and the 15x8 hit 119 mpg on the gun 2 weeks ago but the vertical performance isn't the same. Your OS is running strong. I say go for the 15x8 first.

RC-CAKES

My Feedback: (4)

is that 15x8 speed near sea level elevation? A seasoned Sa125? Curious. I have the same setup - but at 5,700 feet and a newly broken in (3gal) saito. No radar gun but it probably runs around 80-90mph max so far turning 9100. I am betting that once it loosens up more it will run better.

RC-CAKES

My Feedback: (4)

For those of us running SA125s and Keleo twin pipes... is it just me or are the pipe diameters rather small? I have seen other twin pipe pitts style with much larger diameters. A backpressure thing maybe?

skillet92

Rotor I believe that is a back pressure thing because I have a pits made for a os91fs that I converted to work on my 110A and the pipes are bigger than keleo's. I looked at a lot of his trying to decide if I could convert one of his.

rare_bear

My Feedback: (1)

here are some stats on props for ys engines on warbirds i've had in the past:

ys110fz using 30% nitro on a world models 46size mustang (currently flying)
13x10apc 11,070rpm
12x12apc 11,520rpm
12x11apc 12,060rpm
12x14apc 9670rpm

i've used the 13x10 almost exclusively but i hyst got a few 12x12's to try in comparison. the 13x10 gives about a 135mph speed flying level.
we took all of the above measurements yesterday and out field is at 1100 feet in elevation.


ys140sport using 30% nitro on a world models 60 size pettie - much like the topflight herein
14x12apc 10,420rpm.

i no longer have this plane. orginally had a ys110 in it and i ended up replacing that with the 140 which gave it much better take-off power. speed with both engines was about the same.

for all ys engines, i weld up custom pipes using 1/2 inch stainless steel tubing welded to the stock muffler nipple that i saw off at the step down point. this gives an additional 300-400rpm's which translate into power and thus speed.

wind junkie

My Feedback: (1)

Rare Bear,

Are your custom stacks really an improvement over these?

http://www.centralhobbies.com/Exhaust/stacks.html

Doesn't seem like the ID could be much smaller than it already is unless one left off the coupler entirely and had a bare exhaust with no stack.

kochj

Not sure if anyone else has done this:

Installing the Blue nose H9 p-51 retracts in this bird?
The look stellar....

800mZero

My Feedback: (2)

They are okbut not greatthe scissor part of the oleo is very weakly soldered on allowing the wheel to rotate when the break loose, the overall cushion of the gear is rather gritty.

rare_bear

My Feedback: (1)

the pipes at central are 3/8 inch tubing. i am using 1/2 inch.

i used to use those 3/8 inch pipes and going to 1/2 inch gave me an extra 400 rpm's.... which translates into speed.
using a larger tube reduces exhaust backpressure.

i also cut the end of the pipe at an angle. the balongne cut looks kewl and wicked.

Flight 21

Seriously, what is a "balongne cut"?

wind junkie

My Feedback: (1)

Hmmm.. Ok, I believe you. I'm just saying the ID of the exhaust port itself is much smaller than 1/2", so I guess I don't see what good using a bigger pipe does if it's that short anyway, but if you measured that increase I guess it's easy enough to test before vs after.

tiger650

My Feedback: (22)

This was my first summer with this plane and I am delighted with the performance of my OS 110A. I have used an APC 15x8 right from the start and I am getting about 9800 rpm out of it with about a gallon run through it.
I am still getting used to the higer speed on landing, no mishaps so far. Would say a 15x6 or 16x6 help slow it down a little better on final?

Thx.

bucho

My Feedback: (6)

OK, Sorry for ask, but this treade is allready to big to look for it,,, I use to have a saito 100 in my stang until last weak, it fly great but stang needs to fly better thant that, it need more nitro, more power, more speed ,more noise, it is a stang, because of that reasons I instal a saito 125 with a 15x8, now I think will do the job, but, the saito 125 is 3.7 OZ more heavy than the saito 100, and I remember that the CG of the manual was not the very best, can you tell me please wich is the best CG of this bird...??????

rare_bear

My Feedback: (1)

a bologne cut:
http://www.ronayers.com/catalogs/pu/...e=196&secid=33

measured increase in RPM's here (7'th post down):
http://www.rcuniverse.com/forum/m_15...23/key_/tm.htm
now that was my first custom pipe made with chrome moly steel. the stainless tubing i now use has a larger ID than the chrome moly did.

if ya want me to, i can measure the pipe ID for ya.....?

wind junkie

My Feedback: (1)

Wow, that's on old thread. I saw this:

got the new header pipe last night - it's made from the stock threaded black nipple pipe which i sawed in half at the point in which it steps down in diameter.

a friend of mine volunteered to weld a piece of 1/2 inch o.d. chrome-moly bent pipt... so i have a pipe with 3/8 inch inside diameter all the way to the exit which i sawed off with a bolonga cut.


What I'm surprised about is the "step down" muffler adapter that came with my 110 FZ has a constant ID which matches the ID of the exhaust port itself a smooth transition, constant ID, and not very long to begin with only about 2" long total. I thought the Central Hobbies open stacks were also about this long with the same ID maybe a little longer with a gentle curve depending on the angle. I think I have a 70 degree one but have not installed it yet.

So even though your exhaust port wasn't drilled open (it still has that choke point measuring ~3/8") the expansion you get right inside your pipe is enough to make it run faster. That makes me wonder what a pure open exhaust would be in your setup. Or even better, I wonder what would happen if the port itself were widened.

I'm not trying to sidetrack or dispute anything here I just find it fascinating.

Joe

rare_bear

My Feedback: (1)

yeah, maybe because it's such a short distance, it's that much less back pressure going down the remaining length of 1/2 inch tubing.... i don't know how to analyze the fluid dynamics.


here's what i measured on the 1/2 inch pipe: ID=0.425

the nipple is 0.330 inch and the 3/8 inch pipe is (assuming since i don't have one on hand) 0.330


computing the area: 1/2 inch pipe = 0.1418 and the 3/8 pipe is 0.0855

so the 1/2 inch pipe is 65.8% larger in cross sectional area.


well whatever, 400 rpm's is what i measured.

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someone told me that an open exhaust port is not a good thing to do. it can damage the exhaust valve but i can't remember what his explanation was.
ikt's probably the same reason they don't do that in top fuel dragster engines either.