Q-500 Racing Discuss AMA 428, AMA 424, and any other variants of Quickie 500 racing

Viper Thottle Servo Placement

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Old 05-22-2008, 07:06 PM
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YUKONFLYR
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Default Viper Thottle Servo Placement

Where would be the best place to put the throttle servo if I were to use Hitec 225's on the elevons and a 85 for the throttle. I would also like to use a CG tank and that would occupy the forward position.

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Old 05-22-2008, 07:18 PM
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Fxrs_tim
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Default RE: Viper Thottle Servo Placement

I moved the normal throttle servo tray back a bit in the fuse to clear my tank (Jett 6oz slim). I went ahead and did this (although I shortened the tray a bit) to provide structural strength in the forward fuse area. I then mounted my throttle servo just aft of that. I used a couple of short basswood rails to mount my servo on. You need to watch and make sure that your aileron servo clears the throttle servo.

I use JR MN48 servos in the back, a HS225 for the throttle, a 270 mah nicad pack, and a 7 channel Airtronics rx. I put the battery and rx in the main fuse compartment (under the wing) and had the balance come out perfectly. Weight was exactly 3 lbs 12oz.
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Old 05-22-2008, 07:22 PM
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Default RE: Viper Thottle Servo Placement

Place the throttle servo in front of the elv/rud servos all behind the wing. Use a good Sullivan cable and tube with a ball link to the carb, a lighter but perfect servo for the throttle is the Hi-tec 81 vs the 85. A Jett 6 oz. slim tank fits in the cg location with a small amount of fitting. Doug 115
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Old 05-22-2008, 08:36 PM
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Ed Smith
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Default RE: Viper Thottle Servo Placement

Does this answer the question? Here can be seen everything, the elevator servos, the throttle servo just ahead of them, the switch, Reciever, battery and tank on the CG.

Ed S
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Old 05-22-2008, 09:03 PM
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Default RE: Viper Thottle Servo Placement

I use a Jett oval cg tank and a Hobbico mg 12 micro servo in the forward compartment stuck to the side with servo tape. Works great many flites with no problems.
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Old 05-22-2008, 09:44 PM
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Default RE: Viper Thottle Servo Placement

I use a Jett oval cg tank and a Hobbico mg 12 micro servo in the forward compartment stuck to the side with servo tape. Works great many flites with no problems.
The biggest problem I see with that is section 8, paragraph g, of the AMA pylon rules. It states "Rubber grommets shall be used on all servos designed to accept them." I would interpret this as meaning the servo can't be servo taped to the fuse side. While it's just the throttle servo, I'd still rather see more protection from vibration than the tape gives.
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Old 05-23-2008, 06:32 AM
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Ed Smith
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Default RE: Viper Thottle Servo Placement

The biggest problem I see with that is section 8, paragraph g, of the AMA pylon rules. It states "Rubber grommets shall be used on all servos designed to accept them." I would interpret this as meaning the servo can't be servo taped to the fuse side.
Nice catch Gary, I like it.

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Old 05-23-2008, 09:53 AM
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Default RE: Viper Thottle Servo Placement

Just put the rubber grommets in the servo, it doesn't say they need to have a screw go through it

Just take two small square pieces of hardwood, and glue them to the side of the fuse and mount the servo to it through the screw holes.
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Old 05-23-2008, 12:03 PM
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Default RE: Viper Thottle Servo Placement

Dave...I only quoted a portion of the rule...here's the entire paragraph.

"g. All screws holding the servos to the servo rails or trays and holding any trays to the airframe shall be in place and secure. Rubber grommets shall be used on all servos designed to accept them. If the heads of the servo mounting screws are small enough to pull through the grommets, washers shall be used to prevent this."
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Old 05-23-2008, 01:19 PM
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Default RE: Viper Thottle Servo Placement

It still doesn't say that a screw has to be used to secure the servo.
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Old 05-23-2008, 01:40 PM
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Default RE: Viper Thottle Servo Placement

Ok. So with that logic, since it only says "screws" must be secure, so if tape is used for servo mounting, it doesn't have to be secure? Maybe I'll start tying my servos into place with kite string
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Old 05-23-2008, 03:26 PM
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Ed Smith
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Default RE: Viper Thottle Servo Placement

All screws holding the servos to the servo rails or trays and holding any trays to the airframe shall be in place and secure.
Dave, the operative part here is "Shall be in place" Not maybe, or if used, but "Shall"

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Old 05-23-2008, 03:47 PM
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Default RE: Viper Thottle Servo Placement

All screws holding the servos to the servo rails or trays and holding any trays to the airframe shall be in place and secure.

It does not say that there has to be screws, but if you do use screws, they need to in place and secure.
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Old 05-23-2008, 04:02 PM
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Default RE: Viper Thottle Servo Placement

Ok, the same terminology is used regarding engine mounting, so I take it that it's legal to tape the engine on as well? I really don't care regarding the throttle servo, but it is the way I read the rule.

Actually here's a rule that many people have failed to adhear to, even myself.....

Section 8, paragraph C. "The radio receiver and battery pack shall be surrounded by soft foam rubber or other vibration-dampening material and adequately protected against contamination by engine exhaust, raw fuel, or fuel residue."

Since going to FASST 2.4Ghz receivers, I've been servo taping 1/4" foam to the receiver and then attaching it to the fuse side with velcro. The rule states it "shall be surrounded by soft foam rubber....." Mine haven't been "surrounded", they've just had the foam between them and the fuse structure.
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Old 06-01-2008, 01:40 PM
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Default RE: Viper Thottle Servo Placement

Oh Boy here we go. Maybe we should all show up to the next race with a aterny.
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