servos for 2m patternship
05-12-2006 | 05:58 AM
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From: ...Victoria, AUSTRALIA
servos for 2m patternship
hi, i am wondering whether my hitec 475hb servos i have would be enough for a 2m patternship, everyone keeps saying yeh, go for jr 8411s but the fact of $200 australian per servo throws me off a bit, and my hitec 475s have been in my great planes christen eagle II, and i figured if they can hold up in that plane, surely they can put up with a pattern plane, im not sure on whether weight of plane itself is a worry, considering christen eagle is 7-9 kilo and pattern ships are 4-5kg, but i dont really want to spend $1000 on servos when i only have to spend $300 or so, i know ill need higher torque servo for rudder.
i was thinking of the ca models fantasy by the way.
thanks. dav0012
i was thinking of the ca models fantasy by the way.
thanks. dav0012
05-12-2006 | 08:19 AM
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From: Madison,
AL
RE: servos for 2m patternship
Servos are one of the most important links you have, especially with a precision airplane. Resolution and centering are critical, as is high torque around neutral, so the surface comes back to the same place everytime, under any loading or flight condition.
My rule of thumb when choosing servos in order of preference Lowest to Highest is:
Cored analog >coreless analog>cored digital>coreless digital.
The digital amplifier and it's much faster updating seems to counter the effects of the cored motor to a great extent.
There are some exceptions. My experience with Hitec a cored digital (sample of 1) was not good because of a lack of resolution around neutral. This was even after the deadband had been set to the minumum with the Hitec programmer. I didn't want to spend the money to try another, so my experience may not be typical. In contrast, JR cored digitals are very tight, even some cheap DS537s I got for a small airplane. I've had good luck with Hitec coreless digitals after the deadband was set to minimum. Hitec coreless digitals aren't QUITE as tight as JRs, but they are very good. I don't have direct experience with Futaba digitals, but I know that a lot of people who fly Futaba equipment use JR servos.
You also want a FAST servo so it will follow your movements on the stick very quickly. I always run 5 cell packs or a 6 volt regulated Li Ion pack for that reason. Speed should be .15 sec or less at 6 volts as speced by the manufacturer. 6 volts also has the benefit of giving higher torque and holding power.
You can save a few bucks (and weight) by going to JR DS3421's on dual elevators and JR 9411's on ailerons. You can use the SA versions of these servos (nylon gears) and save a few more bucks. They are very high torque for their size, and are very precise. You can also save a few bucks using the JR 8411 SA on rudder, again with nylon gears. Unless you want to do 3D, you don't really need the metal gears, and the nylon gears are essentially slop free and stay that way.
Bottomline, I think you would be unhappy with that choice of servo in a 2M airplane. Buy the best servos you can possibly afford.
Disclaimer: I am not sponsored by anyone, and have no financial interest in any of the companies discussed above.
Jon Lowe
My rule of thumb when choosing servos in order of preference Lowest to Highest is:
Cored analog >coreless analog>cored digital>coreless digital.
The digital amplifier and it's much faster updating seems to counter the effects of the cored motor to a great extent.
There are some exceptions. My experience with Hitec a cored digital (sample of 1) was not good because of a lack of resolution around neutral. This was even after the deadband had been set to the minumum with the Hitec programmer. I didn't want to spend the money to try another, so my experience may not be typical. In contrast, JR cored digitals are very tight, even some cheap DS537s I got for a small airplane. I've had good luck with Hitec coreless digitals after the deadband was set to minimum. Hitec coreless digitals aren't QUITE as tight as JRs, but they are very good. I don't have direct experience with Futaba digitals, but I know that a lot of people who fly Futaba equipment use JR servos.
You also want a FAST servo so it will follow your movements on the stick very quickly. I always run 5 cell packs or a 6 volt regulated Li Ion pack for that reason. Speed should be .15 sec or less at 6 volts as speced by the manufacturer. 6 volts also has the benefit of giving higher torque and holding power.
You can save a few bucks (and weight) by going to JR DS3421's on dual elevators and JR 9411's on ailerons. You can use the SA versions of these servos (nylon gears) and save a few more bucks. They are very high torque for their size, and are very precise. You can also save a few bucks using the JR 8411 SA on rudder, again with nylon gears. Unless you want to do 3D, you don't really need the metal gears, and the nylon gears are essentially slop free and stay that way.
Bottomline, I think you would be unhappy with that choice of servo in a 2M airplane. Buy the best servos you can possibly afford.
Disclaimer: I am not sponsored by anyone, and have no financial interest in any of the companies discussed above.
Jon Lowe
05-12-2006 | 09:59 AM
#3
RE: servos for 2m patternship
I agree 100% wiht Jon note below. I tried both servos and JR is the best for pattern application.
Vicente Bortone
Vicente Bortone
ORIGINAL: jonlowe
Servos are one of the most important links you have, especially with a precision airplane. Resolution and centering are critical, as is high torque around neutral, so the surface comes back to the same place everytime, under any loading or flight condition.
My rule of thumb when choosing servos in order of preference Lowest to Highest is:
Cored analog >coreless analog>cored digital>coreless digital.
The digital amplifier and it's much faster updating seems to counter the effects of the cored motor to a great extent.
There are some exceptions. My experience with Hitec a cored digital (sample of 1) was not good because of a lack of resolution around neutral. This was even after the deadband had been set to the minumum with the Hitec programmer. I didn't want to spend the money to try another, so my experience may not be typical. In contrast, JR cored digitals are very tight, even some cheap DS537s I got for a small airplane. I've had good luck with Hitec coreless digitals after the deadband was set to minimum. Hitec coreless digitals aren't QUITE as tight as JRs, but they are very good. I don't have direct experience with Futaba digitals, but I know that a lot of people who fly Futaba equipment use JR servos.
You also want a FAST servo so it will follow your movements on the stick very quickly. I always run 5 cell packs or a 6 volt regulated Li Ion pack for that reason. Speed should be .15 sec or less at 6 volts as speced by the manufacturer. 6 volts also has the benefit of giving higher torque and holding power.
You can save a few bucks (and weight) by going to JR DS3421's on dual elevators and JR 9411's on ailerons. You can use the SA versions of these servos (nylon gears) and save a few more bucks. They are very high torque for their size, and are very precise. You can also save a few bucks using the JR 8411 SA on rudder, again with nylon gears. Unless you want to do 3D, you don't really need the metal gears, and the nylon gears are essentially slop free and stay that way.
Bottomline, I think you would be unhappy with that choice of servo in a 2M airplane. Buy the best servos you can possibly afford.
Disclaimer: I am not sponsored by anyone, and have no financial interest in any of the companies discussed above.
Jon Lowe
Servos are one of the most important links you have, especially with a precision airplane. Resolution and centering are critical, as is high torque around neutral, so the surface comes back to the same place everytime, under any loading or flight condition.
My rule of thumb when choosing servos in order of preference Lowest to Highest is:
Cored analog >coreless analog>cored digital>coreless digital.
The digital amplifier and it's much faster updating seems to counter the effects of the cored motor to a great extent.
There are some exceptions. My experience with Hitec a cored digital (sample of 1) was not good because of a lack of resolution around neutral. This was even after the deadband had been set to the minumum with the Hitec programmer. I didn't want to spend the money to try another, so my experience may not be typical. In contrast, JR cored digitals are very tight, even some cheap DS537s I got for a small airplane. I've had good luck with Hitec coreless digitals after the deadband was set to minimum. Hitec coreless digitals aren't QUITE as tight as JRs, but they are very good. I don't have direct experience with Futaba digitals, but I know that a lot of people who fly Futaba equipment use JR servos.
You also want a FAST servo so it will follow your movements on the stick very quickly. I always run 5 cell packs or a 6 volt regulated Li Ion pack for that reason. Speed should be .15 sec or less at 6 volts as speced by the manufacturer. 6 volts also has the benefit of giving higher torque and holding power.
You can save a few bucks (and weight) by going to JR DS3421's on dual elevators and JR 9411's on ailerons. You can use the SA versions of these servos (nylon gears) and save a few more bucks. They are very high torque for their size, and are very precise. You can also save a few bucks using the JR 8411 SA on rudder, again with nylon gears. Unless you want to do 3D, you don't really need the metal gears, and the nylon gears are essentially slop free and stay that way.
Bottomline, I think you would be unhappy with that choice of servo in a 2M airplane. Buy the best servos you can possibly afford.
Disclaimer: I am not sponsored by anyone, and have no financial interest in any of the companies discussed above.
Jon Lowe
05-12-2006 | 05:30 PM
#4
RE: servos for 2m patternship
Dave,
I am Team JR sponsored in the US and that has allowed me to use many of the top JR servos int he past 20 years, as well as some of the "sport" varieties in my sport planes. For 2M pattern planes, my preferred setup is:
Ail - 9411sa
Ele- 8417sa (self conversion of 8417 to nylon gears w/ 8231 or 8411sa gear set)
Rud - 8411sa
Thr - 3421sa
Jon L gave you a ton of great general advice for pattern servos. Definitely go digital, nylon gear, and 5cell Nixx or regulate a 7.4 lipo to 6.3 - 6.5 volts - the added voltage is free power and speed. And I would also agree that very often when the servos don't match the TX, the servos are JR - that says a lot for JR servos.
To get the most resolution out of your servos, full surface deflection should equate to 35+ degrees of servo rotation (about 120%+ for ATV/endpoints for JR radios) in each direction, and don't use any more surface deflection than you need. Assuming you have the linkages setup in that manner, there will be much less load on the servo and any servo will perform better.
Very recently JR has introduced the 821 w/ the 7202 TX. The 821 is 1.5 oz and on 6v is rated at 86 oz/in and 0.15 sec - darn impressive specs for a servo with a MAP of $30 USD. It is a cored motor, but I've not noticed any lack of performance attributable to cored motors in any of the cored JR digitals I've run (the best spec'd servos are coreless tho). I think you would be quite happy with the performance of 821s all around, with an 8411sa on the rudder (~180 oz/in and 0.15 sec at 6volts).
Regards,
Dave Lockhart
Team JR
I am Team JR sponsored in the US and that has allowed me to use many of the top JR servos int he past 20 years, as well as some of the "sport" varieties in my sport planes. For 2M pattern planes, my preferred setup is:
Ail - 9411sa
Ele- 8417sa (self conversion of 8417 to nylon gears w/ 8231 or 8411sa gear set)
Rud - 8411sa
Thr - 3421sa
Jon L gave you a ton of great general advice for pattern servos. Definitely go digital, nylon gear, and 5cell Nixx or regulate a 7.4 lipo to 6.3 - 6.5 volts - the added voltage is free power and speed. And I would also agree that very often when the servos don't match the TX, the servos are JR - that says a lot for JR servos.
To get the most resolution out of your servos, full surface deflection should equate to 35+ degrees of servo rotation (about 120%+ for ATV/endpoints for JR radios) in each direction, and don't use any more surface deflection than you need. Assuming you have the linkages setup in that manner, there will be much less load on the servo and any servo will perform better.
Very recently JR has introduced the 821 w/ the 7202 TX. The 821 is 1.5 oz and on 6v is rated at 86 oz/in and 0.15 sec - darn impressive specs for a servo with a MAP of $30 USD. It is a cored motor, but I've not noticed any lack of performance attributable to cored motors in any of the cored JR digitals I've run (the best spec'd servos are coreless tho). I think you would be quite happy with the performance of 821s all around, with an 8411sa on the rudder (~180 oz/in and 0.15 sec at 6volts).
Regards,
Dave Lockhart
Team JR
05-12-2006 | 08:16 PM
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From: Savaneta, ARUBA
RE: servos for 2m patternship
Hello Dave,
I have a quick question here. Aren’t all JR servo rated from 4.8 to 6 Volts ?
I also know more volts could minimize the lifetime of the servos, but don’t really know by how much.
I was thinking on going to 6 volts on my next model, as I’m currently use 4.8 volts and planning on using a lipo battery 7.4 volt
So could we go a bit higher on the voltage with-out damaging them?
Thanks for the info.
Regards
Danny Koolman
www.arubarcclub.com
I have a quick question here. Aren’t all JR servo rated from 4.8 to 6 Volts ?
I also know more volts could minimize the lifetime of the servos, but don’t really know by how much.
I was thinking on going to 6 volts on my next model, as I’m currently use 4.8 volts and planning on using a lipo battery 7.4 volt
So could we go a bit higher on the voltage with-out damaging them?
Thanks for the info.
Regards
Danny Koolman
www.arubarcclub.com
05-12-2006 | 08:29 PM
#6
RE: servos for 2m patternship
Hey Danny,
Yep - the ratings are typically stated for 4.8 and 6.0 volts - nominal voltage for 4 and 5 cell Nicd and Nimh. Nixx freshly off the charger will be ~7 volts for a 5 cell, and all the JR stuff suitable for pattern is rated for 5 cell use. So setting the Vreg to 6.3 or 6.5 is well within the range. I've put 1,000+ flights on some JR servos (with some gear and pot changes) in pattern planes using unregulated 5cell Nixx, so no worries.
Regards,
Dave Lockhart
Team JR
Yep - the ratings are typically stated for 4.8 and 6.0 volts - nominal voltage for 4 and 5 cell Nicd and Nimh. Nixx freshly off the charger will be ~7 volts for a 5 cell, and all the JR stuff suitable for pattern is rated for 5 cell use. So setting the Vreg to 6.3 or 6.5 is well within the range. I've put 1,000+ flights on some JR servos (with some gear and pot changes) in pattern planes using unregulated 5cell Nixx, so no worries.
Regards,
Dave Lockhart
Team JR
05-12-2006 | 08:35 PM
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From: Savaneta, ARUBA
RE: servos for 2m patternship
Hi Dave,
Thanks for the info, it seams that it’s more beneficial to use a constant ( Regulated ) 6 Volts than.
Again thanks for your info.
Regards
Danny Koolman
www.arubrarcclub.com
Thanks for the info, it seams that it’s more beneficial to use a constant ( Regulated ) 6 Volts than.
Again thanks for your info.
Regards
Danny Koolman
www.arubrarcclub.com
05-13-2006 | 04:05 AM
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From: Gothenburg, SWEDEN
RE: servos for 2m patternship
Hitec has specified 475hb to plans up to 8 lbs.
I bought a second-hand 2m pattern plane. It does have Hitec 77 BB on ailerons and to dual elevators. It is not the best but it is working. To the rudder it is a 645 MG. The gearbox on the 645 MG has very big free play after 200 flights. I will change that servo to a JR 8411sa.
I bought a second-hand 2m pattern plane. It does have Hitec 77 BB on ailerons and to dual elevators. It is not the best but it is working. To the rudder it is a 645 MG. The gearbox on the 645 MG has very big free play after 200 flights. I will change that servo to a JR 8411sa.
05-13-2006 | 04:48 AM
#9
RE: servos for 2m patternship
It does have Hitec 77 BB on ailerons and to dual elevators.
You'll notice the difference on centering---much less fighting the model after an ail. input in particular.
05-13-2006 | 11:20 AM
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From: Back home in,
OH
RE: servos for 2m patternship
How much does the transmitter come in to play with these types of servos.
What I mean is there an accuracy limit with the mid price equipment like the 9CAP and a point of diminishing returns is reached?
(the reason I mention that brand and model is because I have one
)
Thanks!
JLK
What I mean is there an accuracy limit with the mid price equipment like the 9CAP and a point of diminishing returns is reached?
(the reason I mention that brand and model is because I have one
)Thanks!
JLK
05-13-2006 | 03:58 PM
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From: Madison,
AL
RE: servos for 2m patternship
Not really. Except for some really cheap radios, modern radios are similar in nature in terms of resolution. With a 9CAP you can definitely tell the difference. In any event, a digital servo will always have more centering and holding power than a similar analog servo. With cheap servos you can also get blow back because they cannot hold against control surface pressure. Also, with a 2 meter airplane, the engine shakes things quite a bit, and servo also has to overcome that effect on centering. Because of the digital serovs much higher sampling rate, it maintains much more holding power at whatever commanded position it is at.
Jon Lowe
Jon Lowe
ORIGINAL: jlkonn
How much does the transmitter come in to play with these types of servos.
What I mean is there an accuracy limit with the mid price equipment like the 9CAP and a point of diminishing returns is reached?
(the reason I mention that brand and model is because I have one)
Thanks!
JLK
How much does the transmitter come in to play with these types of servos.
What I mean is there an accuracy limit with the mid price equipment like the 9CAP and a point of diminishing returns is reached?
(the reason I mention that brand and model is because I have one
)Thanks!
JLK
05-14-2006 | 01:14 AM
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From: Great Bend,
KS
RE: servos for 2m patternship
Hey Super D,
I met you at the Temple/Waco contest. I fly my Temptation with a Futaba 9CAP, A Futaba DP319 Sythesized receiver, JR 9411SA digital aileron servos, 2 JR 3421SA digitals for elevator and a JR 8411SA for Rudder. Throttle is a JR341. I also use a JR matchbox on the elevator servos... The elevator servo's were not quite in synch if I used 2 seperate channels for elevator on the transmitter. The Matchbox fixed that.
Joe Dunnaway
I met you at the Temple/Waco contest. I fly my Temptation with a Futaba 9CAP, A Futaba DP319 Sythesized receiver, JR 9411SA digital aileron servos, 2 JR 3421SA digitals for elevator and a JR 8411SA for Rudder. Throttle is a JR341. I also use a JR matchbox on the elevator servos... The elevator servo's were not quite in synch if I used 2 seperate channels for elevator on the transmitter. The Matchbox fixed that.
Joe Dunnaway
05-14-2006 | 05:47 AM
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From: Madison,
AL
RE: servos for 2m patternship
No suggestions, but one thing to watch with Futaba servos is that some of their digitals are 4.8V ONLY. Don't know why, but it prevents you from gaining essentially free speed and torque by going to 6V, both good things. Seems kind of brain dead to limit themselves that way, given that the other brands don't have that limitation. There is no downside to 6V; I've been running it exclusively for 3 years.
BTW, there is a good article in this months RC Report on 4 cell vs. 5 cell packs, and the myth that systems draw more current on a 5 cell pack, and that you cannot fly as long on a 5 cell pack with the same mah rating as a 4 cell. Good reading, backed up by test data. Bottomline, there is essentially no difference in either current draw or flying time.
Jon Lowe
BTW, there is a good article in this months RC Report on 4 cell vs. 5 cell packs, and the myth that systems draw more current on a 5 cell pack, and that you cannot fly as long on a 5 cell pack with the same mah rating as a 4 cell. Good reading, backed up by test data. Bottomline, there is essentially no difference in either current draw or flying time.
Jon Lowe
ORIGINAL: Super D
How about some futaba suggestions for those that are just partial to futaba.
How about some futaba suggestions for those that are just partial to futaba.
05-14-2006 | 08:26 AM
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From: CebuCebu, PHILIPPINES
RE: servos for 2m patternship
Always preferred Futaba servos myself as I have seen one too many JR servos suddenly lock up and cause a crash. Having said that, there are so many people in my area successfully using JR servo so I know they are fine. For Futabas, I would use a 9154 or 9150 digital or 9102 analog servos for ailerons, 9650s for dual elevators or 9151, 9255, 9252 for single elevators (9402, 9404,9204or 9206 if analog), 9255, 9350, 9151 for rudder (9204, 9402, 9206 for analog). ALL Futaba servos rated at 4.8 volt can safely run with no problem at 6 volts regulated since a freshly charged 4 cell battery would exceed 6 volts. They cannot be run at 6 volts unregulated since a freshly charged 5 cell battery would exceed 7 volts. I have been running these 4.8 volt rated Futaba servos with a 5 cell battery and 6 volt Jaccio regulators for the past 10 years in over a dozen 2x2 pattern planes with not a single problem so you can still get some free torque and speed with Futaba. Just my humble opinion based on my experiences.
05-14-2006 | 08:44 AM
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My Feedback: (45)
RE: servos for 2m patternship
Super D,
I am a Futaba sponsored pilot. I am currently running all of my Futaba digitals on 6.0 volts regulated, and I know of other guys who are running the "4.8" only servos at the higher voltages with no problems. One was even running them unregulated on a LiPo 7.4v pack and had no issues. I personally am running, 9154's on my ailerons, 9351 on the rudder, 9254 (heli tail rotor servo, 50oz torque, .06 transit time at 4.8, so its probably closer to .04 at 6v). In my new ship, I will be running dual elevator servos, simply to counteract the heavier YS 1.60DZ in the front, so I'll be using 9650's mounted in the stab. All of these servos will successfully handle 6.0 volts with no problems.
For cheaper servos, the 3151, and 3152 sport digital servo's are nice servos at a very reasonable price.
Arch Stafford
Team Futaba
I am a Futaba sponsored pilot. I am currently running all of my Futaba digitals on 6.0 volts regulated, and I know of other guys who are running the "4.8" only servos at the higher voltages with no problems. One was even running them unregulated on a LiPo 7.4v pack and had no issues. I personally am running, 9154's on my ailerons, 9351 on the rudder, 9254 (heli tail rotor servo, 50oz torque, .06 transit time at 4.8, so its probably closer to .04 at 6v). In my new ship, I will be running dual elevator servos, simply to counteract the heavier YS 1.60DZ in the front, so I'll be using 9650's mounted in the stab. All of these servos will successfully handle 6.0 volts with no problems.
For cheaper servos, the 3151, and 3152 sport digital servo's are nice servos at a very reasonable price.
Arch Stafford
Team Futaba
05-14-2006 | 02:45 PM
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From: Oslo, NORWAY
RE: servos for 2m patternship
What are all these references to ships"
"Patternship"... "in my new ship"... "my friends ship"?
If I went around refering to my next airplane as a ship people'll think I was mad.
Infact why stop at a ship? From now on I'll refer to my next airplane as a car!
Now, what servos would anyone recomend for my next pattern car?
"Patternship"... "in my new ship"... "my friends ship"?
If I went around refering to my next airplane as a ship people'll think I was mad.
Infact why stop at a ship? From now on I'll refer to my next airplane as a car!
Now, what servos would anyone recomend for my next pattern car?
