Which prop to swing?
03-10-2005 | 03:47 PM
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From: Sandy,
UT
Which prop to swing?
Hi guys,
I have been out of the sport for about 20 years. So yes, I'm old.
I just bought a RTF plane that is probably going to make me bored pretty quick, but I need the stick time, and I am sure it will be a hoot to get back into this again. The question I have is that this plane is sporting a Saito 30 4 stroke. Back in the day, we never had 4 stroke motors. I am anxious to crank this thing up, but I wanted to ask a few basic questions about them first.
1. What prop should I be swinging on this Motor?
2. What Nitro mix should I be using?
It has a zinger 9/6 on it, and I was told that this motor likes 30% Nitro by a Helicopter pilot. So, I was looking for an idea if this was good information or not.
I have been lurking on the board and the folks here seem to not only know a great deal, but be friendly enough to help out. So if anyone has advice, please feel free to let me know.
Thanks
Tom
I have been out of the sport for about 20 years. So yes, I'm old.
I just bought a RTF plane that is probably going to make me bored pretty quick, but I need the stick time, and I am sure it will be a hoot to get back into this again. The question I have is that this plane is sporting a Saito 30 4 stroke. Back in the day, we never had 4 stroke motors. I am anxious to crank this thing up, but I wanted to ask a few basic questions about them first.
1. What prop should I be swinging on this Motor?
2. What Nitro mix should I be using?
It has a zinger 9/6 on it, and I was told that this motor likes 30% Nitro by a Helicopter pilot. So, I was looking for an idea if this was good information or not.
I have been lurking on the board and the folks here seem to not only know a great deal, but be friendly enough to help out. So if anyone has advice, please feel free to let me know.
Thanks
Tom
03-10-2005 | 04:06 PM
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From: South West Rocks N.S.W., AUSTRALIA
RE: Which prop to swing?
Hi Tom,
Four strokes usually produce more torque than two strokes of the same capacity. It still depends on the type of model and flying that you do as to the ultimate prop choice plus a bit of trial and error. Try www.bolly.com.au for a chart. The 9x6 should be fine to bench run but is probably more for a sport plane than a high wing model. If it were a CUB or similar I would go with something like a 10.5x5
I don't think you need to run more than 10% nitro unless the motor is inverted. That's what I run in my Saitos but 72 is the smallest. I would also suggest that you run 20% Coolpower Blue oil without castor. Many will disagree but whilst you don't get the ultimate lean run protection without the castor you also don't get gummed up parts either.
Check you valves are opening correctly and set the gap. Once tuned to you favourite brew you shouldn't have to adjust anything again until you change one of the parameters.
Cheers,
Colin
Four strokes usually produce more torque than two strokes of the same capacity. It still depends on the type of model and flying that you do as to the ultimate prop choice plus a bit of trial and error. Try www.bolly.com.au for a chart. The 9x6 should be fine to bench run but is probably more for a sport plane than a high wing model. If it were a CUB or similar I would go with something like a 10.5x5
I don't think you need to run more than 10% nitro unless the motor is inverted. That's what I run in my Saitos but 72 is the smallest. I would also suggest that you run 20% Coolpower Blue oil without castor. Many will disagree but whilst you don't get the ultimate lean run protection without the castor you also don't get gummed up parts either.
Check you valves are opening correctly and set the gap. Once tuned to you favourite brew you shouldn't have to adjust anything again until you change one of the parameters.
Cheers,
Colin
03-10-2005 | 04:09 PM
#3
My Feedback: (32)
RE: Which prop to swing?
Welcome back Tom,
That Zinger 9X6 will be just fine. You can use 30% Nitro as it will make that engine purr like a cat, but it's sort of a waste on the smaller 4 strokes in a trainer. It is also more expensive.
Saito calls for 10% - 20% nitro. Other than the 30% what I have found out that works well is 15% nitro and 20% fully synthetic oil. A Castor/Synthentic oil blend will work fine but will tarnish around any little leaks in the exhaust. Mainly where the header bolts into the header and the muffler.
My preference on the smaller saitos is 15% nitro 20% synthentic oil
On the bigger Saito and YS 4 strokes is 30% Nitro (Heli blend) which is usually around 24% synthetic oil
Higher nitro, more power, higher oil content, better cooling
That Zinger 9X6 will be just fine. You can use 30% Nitro as it will make that engine purr like a cat, but it's sort of a waste on the smaller 4 strokes in a trainer. It is also more expensive.
Saito calls for 10% - 20% nitro. Other than the 30% what I have found out that works well is 15% nitro and 20% fully synthetic oil. A Castor/Synthentic oil blend will work fine but will tarnish around any little leaks in the exhaust. Mainly where the header bolts into the header and the muffler.
My preference on the smaller saitos is 15% nitro 20% synthentic oil
On the bigger Saito and YS 4 strokes is 30% Nitro (Heli blend) which is usually around 24% synthetic oil
Higher nitro, more power, higher oil content, better cooling
03-10-2005 | 04:20 PM
#4
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My Feedback: (1)
RE: Which prop to swing?
ORIGINAL: Liberator
Hi guys,
I have been out of the sport for about 20 years. So yes, I'm old.
I just bought a RTF plane that is probably going to make me bored pretty quick, but I need the stick time, and I am sure it will be a hoot to get back into this again. The question I have is that this plane is sporting a Saito 30 4 stroke. Back in the day, we never had 4 stroke motors. I am anxious to crank this thing up, but I wanted to ask a few basic questions about them first.
>First of all, to set a 4 stroke up properly you will need a tachometer.
>While it is possible to set one up "by ear", I have only seen one person
>in the last 3 years that could do it, and be close.
1. What prop should I be swinging on this Motor?
>I would SUGGEST starting with a 10x6 or 10x7. I presume you don't
>have the instructions. The 4 strokes I have seen run their best with a
>max rpm of 9800 - 10200. Hopefully someone who is familiar with the
>30 will chime in with what the manual suggests for a prop and rpms.
2. What Nitro mix should I be using?
>Saito's like from 10% - 30% nitro. I have a Saito 72 and was using
>10% nitro. Since I was given a case of 15% last year, I have been
>running 15% nitro with no problems and plenty of power.
It has a zinger 9/6 on it, and I was told that this motor likes 30% Nitro by a Helicopter pilot. So, I was looking for an idea if this was good information or not.
>You can try the 9x6 and see what she tachs at. IMHO, you don't really
>need that much nitro - 10% - 15% should be fine.
I have been lurking on the board and the folks here seem to not only know a great deal, but be friendly enough to help out. So if anyone has advice, please feel free to let me know.
Thanks
Tom
Hi guys,
I have been out of the sport for about 20 years. So yes, I'm old.
I just bought a RTF plane that is probably going to make me bored pretty quick, but I need the stick time, and I am sure it will be a hoot to get back into this again. The question I have is that this plane is sporting a Saito 30 4 stroke. Back in the day, we never had 4 stroke motors. I am anxious to crank this thing up, but I wanted to ask a few basic questions about them first.
>First of all, to set a 4 stroke up properly you will need a tachometer.
>While it is possible to set one up "by ear", I have only seen one person
>in the last 3 years that could do it, and be close.
1. What prop should I be swinging on this Motor?
>I would SUGGEST starting with a 10x6 or 10x7. I presume you don't
>have the instructions. The 4 strokes I have seen run their best with a
>max rpm of 9800 - 10200. Hopefully someone who is familiar with the
>30 will chime in with what the manual suggests for a prop and rpms.
2. What Nitro mix should I be using?
>Saito's like from 10% - 30% nitro. I have a Saito 72 and was using
>10% nitro. Since I was given a case of 15% last year, I have been
>running 15% nitro with no problems and plenty of power.
It has a zinger 9/6 on it, and I was told that this motor likes 30% Nitro by a Helicopter pilot. So, I was looking for an idea if this was good information or not.
>You can try the 9x6 and see what she tachs at. IMHO, you don't really
>need that much nitro - 10% - 15% should be fine.
I have been lurking on the board and the folks here seem to not only know a great deal, but be friendly enough to help out. So if anyone has advice, please feel free to let me know.
Thanks
Tom
03-10-2005 | 05:30 PM
#5
RE: Which prop to swing?
03-10-2005 | 06:23 PM
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From: Springtown,
TX
RE: Which prop to swing?
Funny, I have found just the opposite with my saitos. I have a 56 and a 100. The 100 doesn't give me a bit of trouble, and loves the 15% nitro. The 56 will run off 15%, but doesn't idle reliably, and has much less power than when I run it off of 30%. When I go to 30% in the 100 I can't tell much of a difference. I have some 30% power master heli fuel that i only run in my saito .56.
03-11-2005 | 11:20 AM
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From: Sandy,
UT
RE: Which prop to swing?
THanks very much for all of the great information. Last night as I was going through a bunch of stuff, I found about a 1/2 a dozen 10/6 zingers, all brand new. Would this prop be too big? I am going to try for the first solo tomorrow so after I get the stuff together and the motor cranking, we will see if I remember how to fly.
THanks again guys, I really appreciate the help.
Tom
THanks again guys, I really appreciate the help.
Tom
03-11-2005 | 01:04 PM
#8
RE: Which prop to swing?
Hi!
A 9x6 is way too small for this engine!
At least if you fly at sea level.
A 10x6 prop is what you should use.APC is best.
I have run OS .26 FS engines for 15 years and those run best on 10x5 (10000rpm) props so a little bigger prop is requiered for the larger .30 fourstrokes.
Fuel could be 5%-15% nitro. I always run my OS .26FS on just 5%nitro.
Over here in Europe we also run just 10%-15% all synthetic oil in our fuel
Regards!
Jan K
Sweden
A 9x6 is way too small for this engine!
At least if you fly at sea level.
A 10x6 prop is what you should use.APC is best.
I have run OS .26 FS engines for 15 years and those run best on 10x5 (10000rpm) props so a little bigger prop is requiered for the larger .30 fourstrokes.
Fuel could be 5%-15% nitro. I always run my OS .26FS on just 5%nitro.
Over here in Europe we also run just 10%-15% all synthetic oil in our fuel
Regards!
Jan K
Sweden
03-14-2005 | 12:29 PM
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From: Sandy,
UT
RE: Which prop to swing?
Well, it was not to be.
I get to the field on Saturday and it's pretty windy, so I decide I will just solicite some help and at least get the motor running. There were some really great folks that jumped in and we fueled, glowed and tried to start the Saito 30. When the starter engaged, there was a noise like the prop struck the ground. Sort of a loud click. The experts at the field talked it through and decided that there was something broken on the motor. I took the plane back to the shop where I bought it and the guys were great. They told me they thought the motor was new, but as they slowly turned the motor over, you could hear something inside. They gave me my money back and so now its time to figure out where to go from here. I have a shoestring that my Dad gave to me with an old K&B 40 on it. I got it ready to fly, but I could not get that motor to start.
So, I have a few choices. Stick with the shoestring, and buy a new motor for it.
Invest in some Electric stuff so I can fly every night near the house. I am looking at the some of the new stuff and it's pretty amazing. The little foamys that are high performance are pretty slick. Anyone have any pro's and con's?
Thanks for the suggestions. It's great to be able to bounce stuff off you guys.
Tom
I get to the field on Saturday and it's pretty windy, so I decide I will just solicite some help and at least get the motor running. There were some really great folks that jumped in and we fueled, glowed and tried to start the Saito 30. When the starter engaged, there was a noise like the prop struck the ground. Sort of a loud click. The experts at the field talked it through and decided that there was something broken on the motor. I took the plane back to the shop where I bought it and the guys were great. They told me they thought the motor was new, but as they slowly turned the motor over, you could hear something inside. They gave me my money back and so now its time to figure out where to go from here. I have a shoestring that my Dad gave to me with an old K&B 40 on it. I got it ready to fly, but I could not get that motor to start.
So, I have a few choices. Stick with the shoestring, and buy a new motor for it.
Invest in some Electric stuff so I can fly every night near the house. I am looking at the some of the new stuff and it's pretty amazing. The little foamys that are high performance are pretty slick. Anyone have any pro's and con's?
Thanks for the suggestions. It's great to be able to bounce stuff off you guys.
Tom
03-14-2005 | 12:43 PM
#10
RE: Which prop to swing?
The K&B 40 is a good engine (I have a couple of them) and could probably be used on the RTF. What size engines did it call for? Now as for the K&B, any idea of why it wouldn't start? Did fuel get into carb and thru spraybar? Did it even turn over? Glow plug any good? Reasonably fresh fuel? Did it even try to fire(pop at all)? Did it have any compression? If it didn't fire at all, did you prime the engine at all? More details please. [sm=confused.gif]
The shoestring is not a trainer but the K&B could be put into one. At first I thought you said you took the 4-stroke back but re-reading I think you meant you took the whole plane back, which is correct?
You could also pick up another RTF or ARF trainer and do things right. We'll see how you want to go.
The shoestring is not a trainer but the K&B could be put into one. At first I thought you said you took the 4-stroke back but re-reading I think you meant you took the whole plane back, which is correct?
You could also pick up another RTF or ARF trainer and do things right. We'll see how you want to go.
03-14-2005 | 12:49 PM
#11
My Feedback: (1)
RE: Which prop to swing?
Hi Tom.
You never said what the RTF was, just the engine.
There are several manufacturers out there that make engines that are quite reasonable and run very well. One I have in mind is the Evolution Trainer system which is about a 40 sized two stroke and comes with a three bladed prop which seems to work just fine for most 40 sized trainer aircraft. I have one of their 40 sized engines and it ran just great right out of the box and cost around 70 bucks or so, not bad for a reliable good running 40 sized engine.
I burn S&W 15% nitro standard blend fuel in just about everything (well, that sounds like I am a pro..which I am not but follow my leader very closely and he uses S&W 15% standard blend in his 2 meter pattern plane.. the fuel has a good caster/synthetic oil consentrate for good lubrication).
Anyway, I have several two stroke engines ranging from 40 to 75 and use all the same fuel, and one four stroke, also using the same fuel. Some may argue, but it works and the engines run just fine.
What my instructor suggested is that I set the engine up with a particular prop, then run it using a tachometer, seeking around 10,000 to 11,000 rpm at full throttle then see how it performs in the air. You can adjust prop size to accomodate your flying style, but for the most part, with trainers, you can pretty much use those numbers. If you get an Evolution Trainer system, as I said, it comes with a prop and spinner and will probably do very well with what you are trying to do, and later on, you can re-prop it for any other application that needs a 40 sized engine and do just fine.
Good luck.
Dick.
You never said what the RTF was, just the engine.
There are several manufacturers out there that make engines that are quite reasonable and run very well. One I have in mind is the Evolution Trainer system which is about a 40 sized two stroke and comes with a three bladed prop which seems to work just fine for most 40 sized trainer aircraft. I have one of their 40 sized engines and it ran just great right out of the box and cost around 70 bucks or so, not bad for a reliable good running 40 sized engine.
I burn S&W 15% nitro standard blend fuel in just about everything (well, that sounds like I am a pro..which I am not but follow my leader very closely and he uses S&W 15% standard blend in his 2 meter pattern plane.. the fuel has a good caster/synthetic oil consentrate for good lubrication).
Anyway, I have several two stroke engines ranging from 40 to 75 and use all the same fuel, and one four stroke, also using the same fuel. Some may argue, but it works and the engines run just fine.
What my instructor suggested is that I set the engine up with a particular prop, then run it using a tachometer, seeking around 10,000 to 11,000 rpm at full throttle then see how it performs in the air. You can adjust prop size to accomodate your flying style, but for the most part, with trainers, you can pretty much use those numbers. If you get an Evolution Trainer system, as I said, it comes with a prop and spinner and will probably do very well with what you are trying to do, and later on, you can re-prop it for any other application that needs a 40 sized engine and do just fine.
Good luck.
Dick.
03-14-2005 | 01:26 PM
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From: Sandy,
UT
RE: Which prop to swing?
Sorry about the lack of info. Yes I took the whole plane back. There were a number of ticky tack things that were wrong with the plane. It appeared to have been assembled very hastily. Attention to detail and this planes construction did not collide in the same sentence to often. I was willing to jsut fix all the goofy stuff, but when the engine was toasted, then I really didnt see the point.
As far as the Shoestring. I flew for about 5 years way back in the day and was able to pilot all types of planes with no problems. At this point I feel that I can probably handle the Shoestring, but I had purchased the trainer plane to just get some slower stick time under my belt before stepping off into the deep water. As far as what kind of plane the trainer was, I never really got the name. It is just you're a-typical high wing trainer. It looked like the Hanger 9 alpha trainer. Nothing at all fancy. The fact that it had (I thought) a good motor, all the servo's installed and was essentially a turn key type item was why I purchased it.
When trying to start the K&B, the fuel was brand new, it was 30% nitro. The glow looked good, but to be honest I never pulled it out and lit it up to see if it was actually good. So, major newbie mistake there. I was sort of half way doing the day so to be fair, the motor may be fine.
I am heading in the direction of the big pattern planes eventually. We have several guys in the club that fly these planes, and they have me totally fascinated. It used to be a huge event to get something that big in the air, now it's common place. I guess that and the sheer manuverablity is what appeals to me. Sorry to be vauge before, thanks for the help.
Tom
As far as the Shoestring. I flew for about 5 years way back in the day and was able to pilot all types of planes with no problems. At this point I feel that I can probably handle the Shoestring, but I had purchased the trainer plane to just get some slower stick time under my belt before stepping off into the deep water. As far as what kind of plane the trainer was, I never really got the name. It is just you're a-typical high wing trainer. It looked like the Hanger 9 alpha trainer. Nothing at all fancy. The fact that it had (I thought) a good motor, all the servo's installed and was essentially a turn key type item was why I purchased it.
When trying to start the K&B, the fuel was brand new, it was 30% nitro. The glow looked good, but to be honest I never pulled it out and lit it up to see if it was actually good. So, major newbie mistake there. I was sort of half way doing the day so to be fair, the motor may be fine.
I am heading in the direction of the big pattern planes eventually. We have several guys in the club that fly these planes, and they have me totally fascinated. It used to be a huge event to get something that big in the air, now it's common place. I guess that and the sheer manuverablity is what appeals to me. Sorry to be vauge before, thanks for the help.
Tom
03-14-2005 | 02:00 PM
#13
RE: Which prop to swing?
I've never tried my K&B's on 30%, I've used 10% in long past and 15% these days. Should work though. If not run for a while the spray bar could be gummed up but I'd check the plug first. If you are headed for the big birds you probably should skip the foamies and electrics IMHO. Go ahead and get an ARF, 4-stroke and a GOOD PCM radio that will last into the pattern planes. No sense buying twice if you know where you are heading. The guys in the pattern forum can advise you when you are ready for all that, or of course the guys on your field
03-15-2005 | 12:10 PM
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From: New London, MN
RE: Which prop to swing?
I picked up the one above off the forum a while back so I got it second hand too. But here is a link to top flite which has the same chart on a web page.
http://www.top-flite.com/accys/topq5000a.html
http://www.top-flite.com/accys/topq5000a.html
03-15-2005 | 05:36 PM
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From: Sandy,
UT
RE: Which prop to swing?
dieFluggeister,
Thank you for that killer chart, I also printed it and have it hanging above the work station at home.
I love that little saying at the bottom of you're posts:
"RC is hours of relaxation punctuated by moments of stark terror."
I sort of describe my golf game in a similar fashion "seconds of brilliance surrounded by hours of mediocrity"
Yeah, I am picking up a .40 OS Max to power the shoestring, then I am going to save up and get into a larger pattern plane. You folks have been a huge help so far, I really appreciate all the help, thank you again.
Tom
Thank you for that killer chart, I also printed it and have it hanging above the work station at home.
I love that little saying at the bottom of you're posts:
"RC is hours of relaxation punctuated by moments of stark terror."
I sort of describe my golf game in a similar fashion "seconds of brilliance surrounded by hours of mediocrity"
Yeah, I am picking up a .40 OS Max to power the shoestring, then I am going to save up and get into a larger pattern plane. You folks have been a huge help so far, I really appreciate all the help, thank you again.
Tom
