Thunderchild

Apologies

TC

William Robison

My Feedback: (3)

olds455:

If you are happy with the plane flying the 13x6 your rpm is OK. You might get a little better pull out of hover with a 14x4, probably worth a try. Not a 14x4W please note, the W might be a little too much.

Bill.

William Robison

My Feedback: (3)

olds455:

One further quick note - with the 4: pitch you'll have to be careful not to overspeed the engine in flight.

Bill.

olds455

My Feedback: (1)

Thanks, IF the rains away tommorrow ill try it.

conchohoncho

My Feedback: (120)

How about Pacific Aero's 27% Gee Bee for that 325 Radial? It's an ARF and it looks to have plenty of room for the radial. Has anyone tried this combo?
#260

IronCross

Hey Bill
Runningt into something you might be able to explain to me... I have a Decathlon (draggy 7 lbs) with a Saito .56.. I am running Power Master 15 percent fuel and a APC 13X6 Prop... Static RPM peaks around 10.2k I have it richened to run around 9.6 k...
Qiestion:
In the air when I advance the throttle approximatley the last third of the way I can't seem to hear any increase in the rom and the plane shows no reaction at all... The plane is not overpowered with this set up but will do a nice loop and flys around great at just over 1/2 throttle... And yes my hearing is excellent . Guess what I am wondering is am I getting anything out of the last third of throttle ?... I thought perhaps a 14X4 APC W might do better but read your above post about it beting a little much for this engine.. I am after pull, not speed...
Any thoughts
Thanks
IC

William Robison

My Feedback: (3)

Bone:

Back to your question about moving the breather nipple on the Saito engines.

I’ve not yet done more than rough planning, but “My� location for the port is as close to the exhaust tappet guide as I can get it. The housing is thickest there, and it’s as far behind the gear as it will go.

The gear is a fairly close fit in the top of the case, and while I don’t know it will interfere with the breather I’d rather not find it does.

If you want to get fancy put two nipples in each rocker cover. Run the vent hose from your new nipple to either rocker box, then connect the other nipple on that one to one of the nipples on the other, and the last nipple will be the vent to the air. This will take the blow from the bottom end, force it through both rocker boxes, ensuring good lubrication to the valve gear as well as the cam and tappets.

What I’m trying to work up does all this with metal pipes, exept for the last nipple for the hose.
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IC:

It’s perfectly normal to have a small difference from mid throttle to full. Consider. Idling at 10%, then you go to half throttle to taxi. You have opened the throttle five times as wide as it was at idle. But when you go from 60% or 70% to full you haven’t even doubled the open area.

One of my old tricks with a computer radio is to set the expo on the throttle to give med ½ throttle with about 1/3 stick movement. Makes it feel much more linear in response.

Bill.

IronCross

Dr Bill
I had a bit of a brain fade when I made my post.. my .56 has a 12X6 on it not a 13X6.
I understand what you are saying about the barrel movement but it doesn't really explain it...
I can clearly hear the throttle change with the engine static on the ground... Just not in the air.
I have a second Decathlon (slightly larger) with one of my .72's on it running the 13X6. I can hear
the entire throttle range with this set up in the air ... I have a second .56 (same set up) on a
WM 30 size Extra and I can detect the entire range with that set up...
Kind of reminds me of the differance in engine response in my truck with a heavy load and no load..
That would tell me the .56 is overloaded yet the static rpm's give no indication of that... Is there more
load on an engine/prop when it is moving through the air then when it is sitting static.. Seems like since
the engine "unloads" in the air there is less load...
Also seems to me I am chasing my tail here...
Any thoughts on this...
Plan B calls for a 13X4 APC on it next trip to the field unless you disagree..
Thanks again
IC

Sarge1947

I have the option of mounting my FA 65 either upright or upside down. Which way would cause this Noob less problems?
2. What kind and where should I get an engine mount?
Thanks, Sarge

William Robison

My Feedback: (3)

Sarge:

Probably the least problem will be neither upright nor inverted, but rather sideways. But if you can get the fuel tank high enough upright would be preferred.

The FA-65 is a relatively heavy engine without much vibration, almost any mount will work fine. Just for one example the Dave Brown composite mounts are good, but there are many others as good. Get whatever is most convenient, either at your LHS or mail order.

Bill.

William Robison

My Feedback: (3)

IC:

With a low pitch prop rpm in the air is usually higher than on the ground, but a high pitch prop can be in a stall condition on the ground and actually turn less rpm in the air when it isn’t stalled.

The low pitch prop, running close to pitch speed, will allow the engine to rev more freely in the air and often the engine rpm will follow the throttle closely. The high pitch prop gives the engine more load at the same rpm, and often the difference between 60% and 100% throttle is only a few hundred rpm, if that much.

The engine’s response in the air depends on the match of the power, prop, and the drag of the plane.

Let’s take a quick detour to general aviation for an example.

You have your J-3 in the foothills of the Rockies, and need a good climb. You have installed a 75� pitch prop and it gets you up fast, but for your 75 mph cruise you have to run 1500 rpm. The engine feels strong, and just a little push on the throttle gets you up to 1750, but the plane doesn’t go any amount faster – too much drag.

Then you move over into the central plain, a fast climb isn’t needed here so you install a prop with a 90� pitch. Now your 75 mph cruise comes at 1250 rpm. Good fuel savings, and the engine will last longer too. But when you go to full throttle you only get 1500 rpm, and again the air speed is almost the same as it was at 1250.

With both props you have no trouble getting 1500 rpm for a mag check, the 90� is running at stall and losing the load on the engine.

Same thing happens with our models. If propped with a low pitch for 3D flying the engine will scream in the air, propped for sport the rpm will be lower, at least in the air, and the throttle wont feel as crisp.

Hope this clears it up, at least a little.

Bill.

Hobbsy

My Feedback: (102)

W, I broke in my new Saito .30 GK a little while ago, usual Saito break in, as in a non event. After 40 minutes it was turning a Graupner 10x5 at 10,511 at peak about 10,300 at safe setting, same as my old one with your magic cylinder. It has the older pointy McCoy plug which worked fine.

IronCross

Thanks Bill
Off in the distance I see a glimmer of light. Going to have to think on this one....
]IC

William Robison

My Feedback: (3)

IC:

How about putting it this way: Light load, (3D style prop) gives crisp throttle respponse. A heavier load gives a sluggish throttle.

Bill.

William Robison

My Feedback: (3)

Dave:

Your 30GK comes from the factory with the "Magic Cylinder." It's only right that it should run as well as the other one.

Haw.

Bil.

IronCross

Now that makes it pretty simple Bill.. I was thinking that a prop should work harder in a static situation then while moving through the air… But as you pointed out there are a lot of other factors involved here…
I put a 1 3X4 on it and ran it in my garage today… Gained 4 or 5 hundred rpm… It seemed to run good on the ground… But as we have discussed I won’t know till my next trip to the field if I have gained anything.. I am not trying to do 3D with the Dec… Just like to be able to do a little bigger loops and stuff.. Plane calls for up to a .52 4stroke… Only thing I can figure is they must have some powerful 4 strokes in Viet Nam….
Thanks IC

William Robison

My Feedback: (3)

IC:

Do remember that a 4" pitch is going to allow you to overspeed the engine easily, so be careful.

Bill.

IronCross

Thanks Bill
I have the static rpm set at 10k ... That is around 4 hundred higher then it waa set with 12X6.. Shouldn't be to high should it ?.. Should probably go ahead and just stick a .72 in it and be done with it.
IC

William Robison

My Feedback: (3)

IC:

10K is fine with your little FA-56, try not to go over 12K in the air.

And yes, you could be expecting a little too much from the 56. Didn't you say seven pounds?

Bill.

IronCross

Yes, seven pounds... Like I said though, specs call for a .52. It's a Pheonix Dec sold by Tower.... They probably specked it for an OS 4 stroke...
Thanks for the help...
You add a lot to this hobby
IC

William Robison

My Feedback: (3)

So they said it's for a 52. Did they also say seven pounds, or did they say five?

And let's not be mentioning Oriental Scrap here please. Haw. With some few exceptions they are heavier and less powerful than a Saito of the same displacement.

Bill.

bldrums

I recently purchased a Saito 1.25 and I was suprised at the exhaust trail it left. I am used to my Saito .50, .82 , .91 engines and while they do "puff" out visible exhaust going to wot, they do not leave a trail in the air. ( all on the same Morgan Cool Power fuel ). I just wonder why the 1.25 makes a very pronounced "smoke trail" and the .50 to .91 range make little or none. I'm just curious, no big deal.
FYI ;the 1.25 , like my other Saitos, is flawless.

thanks,
Bill

w8ye

My Feedback: (16)

It may be a little richer than the others?

IronCross

REQUIRES: Engine: .46-.51 cu in (7.5-8.3 cc) 2-stroke
OR .52 cu in (8.5 cc) 4-stroke
Wingspan: 66" (1675mm)
Wing Area: 701 sq in (45 sq dm)
Weight: 7lb (3180g) approximate
Wing Loading: 23 oz/sq ft (71 g/sq dm)
Fuselage Length: 50" (1270mm)

Sorry for mentioning Other Stuff here... Another brain fade on my part, forgot where I was
I figured if a .52 would power it a Saito .56 would give me more then enough
power....
It's a nice plane... Lota bang for the buck... Be even nicer with a .72 in it.. I am going to try the 13X4 just to satisfy my own curiosity but will probably end up putting one of my .72's in it...

Thanks Bill
IC

pilotpete2

Hi All,
Not a lot of experience with 4 strokes. Well yesterday I was running up an old production Saito .65 that I had bought 10 years ago NIB (has the one piece black anodized muffler) and things very going well getting the transition right (also has the air bleed carb.) then suddenly no idle[:@], found the problem real fast, the muffler pipe had cracked at the bend so I was losing muffler pressure as the crack opened. My question to all the Saito Guru's out there, ever hear of this happening? I'll plan on ordering a manifold and muffler from horizon on Monday, if I have to, I guess Now if anybody has an old one piece muffler laying around, "let's make a deal"[8D]
Regards to All,
Pete