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Old 04-09-2009, 08:47 AM
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Re: Extreme Flight 88" 50cc Extra 300 Build!

Quote:
Originally Posted by pani View Post
I would like to ask something since Charles and the manual both state the same thing. The 4" servo arm requires 70% end points for bevel to bevel deflection at 100% dual rates on my JR X9303 driving a Spektrum AR9100 Rx which in turn controls a Hitec HS7955TG. How come this is optimal? Assuming that you can't, by any means, screw the rudder horn assembly up, this means that a 3" is more practical as it requires 115% end points upping up the available resolution and the torque to the surface. Of course there is a chance (very big one) that I have no idea about mechanical advantage etc but I thought that more end point travel, more resolution.
Thanks for your thoughts.
Pani,

Something is different on your setup. I'm running a X9303 and AR9100 and turned the end points up to get max throw with a 4" SWB offset arm. What brand servo arm did you use? If it was an 4" MPI it is a different size than a 4" SWB.
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Old 04-09-2009, 09:57 AM
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Re: Extreme Flight 88" 50cc Extra 300 Build!

The servo arm should be the same width as the rudder control arm clevis'. If not, one cable or the other will go slack.
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Old 04-09-2009, 10:55 AM
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Re: Extreme Flight 88" 50cc Extra 300 Build!

Quote:
I would like to ask something since Charles and the manual both state the same thing. The 4" servo arm requires 70% end points for bevel to bevel deflection at 100% dual rates on my JR X9303 driving a Spektrum AR9100 Rx which in turn controls a Hitec HS7955TG. How come this is optimal? Assuming that you can't, by any means, screw the rudder horn assembly up, this means that a 3" is more practical as it requires 115% end points upping up the available resolution and the torque to the surface. Of course there is a chance (very big one) that I have no idea about mechanical advantage etc but I thought that more end point travel, more resolution.
Thanks for your thoughts.
I see what you're saying but the pull pull rudder is not the same as other surfaces. You can't max out your mechanical advantage with the pull pull rudder. You have to match your servo end points to the rudder surface's end of travels. These end of travels end up as a result of the control horn widths, horn offset, and the recommended servo arm width and servo arm offset to minimize slack. It also takes into account the straight or crossing cables. It just depends on the plane and the recommended pull pull setup. It normally ends up very close to, but not exactly a 1:1 mech advantage. This explains why you need gobs of torque for rudder servos.
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Last edited by JoeAirPort; 04-09-2009 at 11:42 AM.
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Old 04-09-2009, 09:40 PM
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Re: Extreme Flight 88" 50cc Extra 300 Build!

Hey Charles,

Could you post a picture of how you set up your electronics inside? I'm curious as to how the balance works out before I start to just mount stuff. Does it tend to be tail heavy or nose heavy?

Sincerely,
tm
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Old 04-09-2009, 11:05 PM
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Re: Extreme Flight 88" 50cc Extra 300 Build!

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Originally Posted by t-moller View Post
Hey Charles,

Could you post a picture of how you set up your electronics inside? I'm curious as to how the balance works out before I start to just mount stuff. Does it tend to be tail heavy or nose heavy?

Sincerely,
tm
TM,

I don't have a picture of the inside of the one with the DA-50 and RE-2. This picture is of my extra with a Brillelli 60. The batteries need to be up beside the fuel tank with the DA/RE-2. I'll see if Jason will post some pictures of his. I really like the Brillelli on the plane it's just a shame you can't get them anymore.

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Old 04-09-2009, 11:19 PM
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Re: Extreme Flight 88" 50cc Extra 300 Build!

Here's how mine was with the DA 50 and RE2, rx and ignition batteries are in the motor box. I have another one coming next week, think I'm going with the ES pipe this time, we'll have to get all our E.F. planes together at the Nall this year for a group photo for the website, and a group hover would be awesome also!!

Lee
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Old 04-09-2009, 11:22 PM
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Re: Extreme Flight 88" 50cc Extra 300 Build!

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Originally Posted by mxcop View Post
Here's how mine was with the DA 50 and RE2. I have another one coming next week, think I'm going with the ES pipe this time, we'll have to get all our E.F. planes together at the Nall this year for a group photo for the website, and a group hover would be awesome also!!

Lee
I have an ES pipe, you are gonna have to put you batteries in the motor box to get it to balance. Or consider using a heavier spinner like a true turn.
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Old 04-09-2009, 11:42 PM
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Re: Extreme Flight 88" 50cc Extra 300 Build!

Quote:
Originally Posted by cjcyclesrc View Post
Pani,

Something is different on your setup. I'm running a X9303 and AR9100 and turned the end points up to get max throw with a 4" SWB offset arm. What brand servo arm did you use? If it was an 4" MPI it is a different size than a 4" SWB.

Charles,

Thanks for your clarification. I would think that a 4" offset arm is a 4" inch offset arm. I have the MPI 4" and 3". Now you've got me thinking. Do me a favor mate. Can you please measure hole to hole on your 4" SWB arm. Looking at your photos it looks smaller than the tunnel pipe width. My 4" MPI is (as expected) 4inch hole to hole.
EDIT: Charles, no need to go into trouble mate. From SWB's website: Please note: Offset arms are for pull-pull and do not measure there
designated length but are for that length rudder horn.

This is the reason I was getting such low ATV's with the MPI and had to go with the 3 inch. Your photo alerted me.

Joe, wires are crossed as per the manual.

TM,

Both of my A123 batteries are in front of the fuel tank with my DA/RE2 combo. It IS tailheavy at that location. I will try and get a pic.
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Last edited by pani; 04-10-2009 at 01:40 AM. Reason: Updated info
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Old 04-09-2009, 11:52 PM
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Re: Extreme Flight 88" 50cc Extra 300 Build!

Quote:
Originally Posted by JoeAirPort View Post
I see what you're saying but the pull pull rudder is not the same as other surfaces. You can't max out your mechanical advantage with the pull pull rudder. You have to match your servo end points to the rudder surface's end of travels. These end of travels end up as a result of the control horn widths, horn offset, and the recommended servo arm width and servo arm offset to minimize slack. It also takes into account the straight or crossing cables. It just depends on the plane and the recommended pull pull setup. It normally ends up very close to, but not exactly a 1:1 mech advantage. This explains why you need gobs of torque for rudder servos.

I didnt qiete fallow the whole story hear but the way i do it it set my ATVs to 140 then set my rudder throw with my dual rates. Works out really good for me this way. And just try to get as close as you can to the arm length as the measurment accross the rudder control horns to the outside hols.
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Old 04-09-2009, 11:57 PM
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Re: Extreme Flight 88" 50cc Extra 300 Build!

DA 50 and ES pipe need 3 , 3.5 ounce batteries in the motor box for a CG at 6 3/4 inch. Granted I have a CF spinner and wooden prop.

Also I finally got some graphics from Bad Brad, Awesome stuff as usual. One of my favorites is the wheel pants logo, its a recreation of the actual logo they put on full scale extras.
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Old 04-10-2009, 01:05 AM
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Re: Extreme Flight 88" 50cc Extra 300 Build!

Quote:
Originally Posted by pani View Post
Charles,


TM,


Both of my A123 batteries are in front of the fuel tank with my DA/RE2 combo. It IS tailheavy at that location. I will try and get a pic.
First off thanks for the pictures. This sure will help as one starts to lay things our with the knowledge of how the plane usual balances out. Now I'm glad I got the three Li-on 2600mha batteries. Better to have some useful weight in the nose then just plain led.

I suppose I could also push the DA forward a little bit.

What about using two Hitech 7985 on the elevators. They are 0.11 oz lighter and a bit faster too. I'm currently using two on my 94" Aerowork Yak54 and they seem to do it just fine?

Sincerely,
tm
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Old 04-10-2009, 01:25 AM
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Re: Extreme Flight 88" 50cc Extra 300 Build!

It should work but keep this in mind. The Hitec 7955 and 5955 servos were spec'ed at 333oz of torque. TBM did testing on them and showed that they were only producing 74% of advertised torque In real world applications. I have not seen any tests on the 7985 but it is spec'ed at 172 oz at 6.0 volts. If it suffers the same fate as the other Hitec servos it may only give you 74% of that or 128 ounces of torque and extreme flight recommends 200 ounce torque on all surfaces. Chances are you would be okay but keep an eye on it for the first few flights checking for flutter or blow back.

You may want to give Power HD servos a good look they were tested and put out 224 ounce torque at 6.0 volts and they are much much cheaper than hitec. My buddy has these servos on his 50CC bird and they were flawless at only 34 bucks a pop.

http://www.troybuiltmodels.com/items/HD-9150MG.html


Servo Comparison:

http://www.troybuiltmodels.com/ns/ac...mparison.shtml

And for what its worth I am running Hitec 5955's on all surfaces. If I had 2 do it again I would have gotten power HD 9150 servos.
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Old 04-10-2009, 01:32 AM
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Re: Extreme Flight 88" 50cc Extra 300 Build!

TM,

Can't go wrong with the 7985's. I use the same on my Extra, and the older 5985's on my Yak. Driving the elevators on both planes.

BTW I forgot to mention that I have a wooden prop and a GF spinner. Ignition Fromeco LiIon is mounted at the extreme front edge of the firewall.
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Old 04-10-2009, 02:02 AM
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Re: Extreme Flight 88" 50cc Extra 300 Build!

Quote:
Originally Posted by crash-n-burn View Post
It should work but keep this in mind. The Hitec 7955 and 5955 servos were spec'ed at 333oz of torque. TBM did testing on them and showed that they were only producing 74% of advertised torque In real world applications. I have not seen any tests on the 7985 but it is spec'ed at 172 oz at 6.0 volts. If it suffers the same fate as the other Hitec servos it may only give you 74% of that or 128 ounces of torque and extreme flight recommends 200 ounce torque on all surfaces. Chances are you would be okay but keep an eye on it for the first few flights checking for flutter or blow back.

You may want to give Power HD servos a good look they were tested and put out 224 ounce torque at 6.0 volts and they are much much cheaper than hitec. My buddy has these servos on his 50CC bird and they were flawless at only 34 bucks a pop.

http://www.troybuiltmodels.com/items/HD-9150MG.html


Servo Comparison:

http://www.troybuiltmodels.com/ns/ac...mparison.shtml

And for what its worth I am running Hitec 5955's on all surfaces. If I had 2 do it again I would have gotten power HD 9150 servos.
Hey Crash,

I checked the link and yes that would be a savings. The weight was in between the 7955 & 7985.
Well the 55's should be on their way so what the heck. With the info on the CG I will try and push what I can as forward as possible.

Can't wait until big packages show up.

tm
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Old 04-10-2009, 10:01 AM
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Re: Extreme Flight 88" 50cc Extra 300 Build!

TM,

Good choice on the 55's. The 85's work perfectly fine, but its worth the little extra to get the titanium gears.
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