Welcome to Club SAITO !
06-06-2020, 03:33 PM
thank you for the good words! it just popped in my head and I went and made it.
a funny thing about, that Word Models P-40. people recommend only 5mm of Aileron throw. that's not much at all.
BTW, the plane has a 57" span and there are guys on Y.T. flying it with 91 Fs in it and one guy has a 26cc gasser in his.
Jim
a funny thing about, that Word Models P-40. people recommend only 5mm of Aileron throw. that's not much at all.
BTW, the plane has a 57" span and there are guys on Y.T. flying it with 91 Fs in it and one guy has a 26cc gasser in his.
Jim
Cant even speak that language.
My poor skills have limited me to trainer level bi planes😞
And my nerves are the better for it.
Sure love watching my brother in law "Chuck Yeager" fly his 1/4 scale single seat fighters.
It's awe inspiring for this poor old carpenter.
And enough for my nerves.
😁
06-07-2020, 06:23 AM
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Keleo muffler
06-07-2020, 11:35 AM
For all you YS haters out there you'll be happy to know the "low time" 91 AC/FZ I purchased doesn't run and needs about $80.00 in parts to revive it. Bearings, gasket set, oring kit, regulator kit and a thorough cleaning might git-r-done. Haven't even got it completely disassembled yet.
On a positive note, it is purdy.
On a positive note, it is purdy.
Last edited by Glowgeek; 06-07-2020 at 12:34 PM.
06-07-2020, 06:28 PM
My Feedback: (1)
For all you YS haters out there you'll be happy to know the "low time" 91 AC/FZ I purchased doesn't run and needs about $80.00 in parts to revive it. Bearings, gasket set, oring kit, regulator kit and a thorough cleaning might git-r-done. Haven't even got it completely disassembled yet.
On a positive note, it is purdy.
On a positive note, it is purdy.
Jim
06-08-2020, 02:43 AM
06-08-2020, 12:13 PM
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Just bought an adapter for my FA120 Fatheads from Tru Turn and it calls for a 1/2" diameter hole in the prop. Just don't happen to have a 1/2" step reamer around.... Drill press I Suppose, but don't really trust it. I am using a 14-7 Graupner 3 blade prop so it is darned near impossible to hold it in place to do it on a drill press. Any ideas?
06-08-2020, 12:33 PM
Hmm, my MAS 14 x 7 3 blade has a 1 1/4" hub, so 1/2" is doable. Could always use a step bit once you have the blade centered. Step it until you reach the 1/2" diameter like a reamer does, then finish the hole with a 1/2" bit.
06-08-2020, 01:06 PM
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There seems to be plenty of room. I went ahead and drilled it out by using a bit the size of the existing hole of the prop on the Drill press and centering the prop. I then braced it using 3- 1/2" square blocks clamped in place, removed the smaller bit and replaced it with a 1/2" bit and drilled it out. I am not totally confident that it is centered. I test ran the thing the other day and the engine "flew" itself off the test stand! I am not sure if it shook itself off or I didn't have it tight enough to the stand. Needless to say, I am a little skittish to try it again.....
06-08-2020, 06:48 PM
The 180 is back together with new valve springs and bearings. Ran a 14 oz. tank through it set rich to blow out the castor assembly lube. Filled the tank again and almost got it tuned for tach readings when the sky opened up.
Safe to say, it's a beast!
Safe to say, it's a beast!
06-08-2020, 07:17 PM
I'm considering maybe getting a 3D twist and run a 91 on it. Manual shows an 82. Would the 91 be too much or just right and what prop would I run? My Somethin Xtra is fun, but not capable of 3D without serious control surface work, as in making them all much larger. Besides I like it the way it is.
06-09-2020, 03:37 AM
I'm considering maybe getting a 3D twist and run a 91 on it. Manual shows an 82. Would the 91 be too much or just right and what prop would I run? My Somethin Xtra is fun, but not capable of 3D without serious control surface work, as in making them all much larger. Besides I like it the way it is.
06-09-2020, 05:12 AM
15 4 sounds about right. I had to sit and think about the pitch and stuff and I finally got it. want to go fast on a horizontal, small diameter, high pitch, want to go vertical and don't care about speed large and low. So if I want to slow my Xtra down, then a 13 x 4 would work, but if I wanted it to go faster and be a real screamer, a 12 x 10. I think it has a 13 x 7 on it now. I really need to stock up on props, but when ever I go to a swap I find all these iddy biddy baby props no larger than 10". I don't have anything with a 10" prop, 11 is the smallest. Think I will get a pile of wood ones ordered after I do a list of sizes I use.
06-09-2020, 06:01 AM
For wood props Xoar is a great choice. Not as effecient as an apc but excellent for thrust in the lower pitches and very popular amongst 3D pilots. Myself included!
Yes, for more thrust you need a larger diameter prop. That will force the use of a lower pitch prop to keep the engine rpms up in a usable range.
Yes, for more speed you need a higher pitch prop. That will force the use of a smaller diameter prop to keep the engine rpms up in a usable range.
Now here's the thing, when going for thrust (large dia, low pitch props) the engine will not unload much in the air vs. rpms on the ground. That means you can prop for a ground rpm close to what you want your engine to peak at in the air. When going for speed (small diameter, high pitch props) the engine can unload a lot in the air and over rev, especially with a slick airframe like a P51, so you must prop for lower rpms on the ground.
A good rule of thumb for prop loading is: Go up or down 2 pitch sizes for each 1" change in diameter. Example: 12x10, 13x8, 14x6 & 15x4 props would all provide similar loading to the engine and so peak rpms on the ground would be similar.
In the air it's a different story! That 15x4 may unload 200 rpm or so on a high drag 3D plane whereas the 12x10 may unload 1500 rpm on a low drag slick airframe!
All sounds simple huh? Well it is, for 3D and high wing planes (high drag) but not for speed planes. Predicting how much a prop will unload on a speed plane is an exercise in futility. You have to try a handful of props to see which one will produce top speed without over revving the engine. Cutting props down by 1/4" increments is commonplace with pylon pilots.
saito Saito SAITO!
Yes, for more thrust you need a larger diameter prop. That will force the use of a lower pitch prop to keep the engine rpms up in a usable range.
Yes, for more speed you need a higher pitch prop. That will force the use of a smaller diameter prop to keep the engine rpms up in a usable range.
Now here's the thing, when going for thrust (large dia, low pitch props) the engine will not unload much in the air vs. rpms on the ground. That means you can prop for a ground rpm close to what you want your engine to peak at in the air. When going for speed (small diameter, high pitch props) the engine can unload a lot in the air and over rev, especially with a slick airframe like a P51, so you must prop for lower rpms on the ground.
A good rule of thumb for prop loading is: Go up or down 2 pitch sizes for each 1" change in diameter. Example: 12x10, 13x8, 14x6 & 15x4 props would all provide similar loading to the engine and so peak rpms on the ground would be similar.
In the air it's a different story! That 15x4 may unload 200 rpm or so on a high drag 3D plane whereas the 12x10 may unload 1500 rpm on a low drag slick airframe!
All sounds simple huh? Well it is, for 3D and high wing planes (high drag) but not for speed planes. Predicting how much a prop will unload on a speed plane is an exercise in futility. You have to try a handful of props to see which one will produce top speed without over revving the engine. Cutting props down by 1/4" increments is commonplace with pylon pilots.
saito Saito SAITO!
Last edited by Glowgeek; 06-09-2020 at 07:48 AM.
06-09-2020, 02:26 PM
FA-180 (The Beast)
Did the final tuning today.
FA-180
15% Nitro
Humid as all get out
APC 16x8 (sport)
Peak 9420
Idle 1650
HP: 3.156
Thrust: 16.52 lbs
For sale, a very low time engine with new bearings and valve springs. Immaculately clean inside and out. Piston ring still has factory grinding marks, not yet fully broke in imo. Runs great at all rpms. $200.00? PM if interested.
Lonnie
FA-180
15% Nitro
Humid as all get out
APC 16x8 (sport)
Peak 9420
Idle 1650
HP: 3.156
Thrust: 16.52 lbs
For sale, a very low time engine with new bearings and valve springs. Immaculately clean inside and out. Piston ring still has factory grinding marks, not yet fully broke in imo. Runs great at all rpms. $200.00? PM if interested.
Lonnie
Last edited by Glowgeek; 06-09-2020 at 02:54 PM.
06-10-2020, 04:51 AM
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I like the sound of that! The 100 flew it ok. I just noticed that the 100 and 125 have the same mounting pattern. Hmmmm, maybe I'll put the 125 in the TF P51 instead of the 115, that way I can put the 115 in my Strega 46-55 size bird as originally intended. Woohoo!
46 Size Strega + Saito 115 + APC 13x13.5N + left thumb sounds like a formula for fun to me
The 100 flew it ok. I just noticed that the 100 and 125 have the same mounting pattern. Hmmmm, maybe I'll put the 125 in the TF P51 instead of the 115, that way I can put the 115 in my Strega 46-55 size bird as originally intended. Woohoo!46 Size Strega + Saito 115 + APC 13x13.5N + left thumb sounds like a formula for fun to me