boom mounted tail servo, does which way matter?

[istandalone]

i've pretty much finished my 550 build, and i used the boom mount for the tail servo. of course i didn't watch finless video until after, but i think i'm all set. my question is, on the vid bob had the servo mounted with the output shaft/servo horn facing the tail rotor and i ended up mounting mine with the output shaft and horn facing front. as long as i reverse the rudder channel i should be set, right? do i also need to reverse the gyro (401/9254 combo)? in the end after i reversed the rudder, right rudder input still pushes the tail slider in the correct direction- towards the tail case. maybe i'm just being paranoid, but i have to hear it from someone else. and i don't want to have to make a new linkage to accomodate flipping the servo, getting the proper bends in was quite a task.

[istandalone]

oh yea, one more thing. bob mentions that this heli when using the 401 you should set it up in rate mode first. anyone know why? i've been told time and time again the 401 works best with the tail pitch slider centered. anyone have an opinion?

[dave26985]

istandalone, as far as the servo position you should be OK as long as you have the switch in the right position to move the slider to the left when you push the tail to the right, and slide to the right when you push the tail to the left. ( when looking at it from the back.)
As far as your gyro question I am curious about the same thing.
Later Dave.

[mjdee14]

Originally Posted by istandalone

oh yea, one more thing. bob mentions that this heli when using the 401 you should set it up in rate mode first. anyone know why? i've been told time and time again the 401 works best with the tail pitch slider centered. anyone have an opinion?

I think what is meant is you initially set it up with the slider in the middle....then set the end points using the 401 so it does not bind in either direction....THEN...you set up the heli in rate mode by getting light on the skids...see which way the nose turns then move the whole tail servo in the proper direction to stop the movement, now you still have a "centered" servo, but the heli will hover with no rudder input.

Now when you switch to HH you have a centered servo and proper end point adjustments.

You can't do this with the servo mounted in the stock or CF frames....there is no adjustment of the servo other than subtrim or regular trim...

it's really easy once you have done it a few times...the idea is to get the heli to hover strait as close as possible...then the gyro and servo will not have to work so hard to maintain heading...and will use less amps also.

You basically do this with most typed of gyros...

[GatoVolador]

As far as the output shaft orientation is concerned it really doesn't matter. You want to orient it such that you have as straight as shot to the pitch slider ball as possible. If the servo is moving the pitch slider in the wrong direction than just fix it via servo reversing in your radio or gyro if it supports it. You want to setup initially in rate mode so the gyro isn't messing with you as you adjust your end points so you don't overdrive the servo. You shouldn't hear any buzzing from the servo at the extremes. Once you have this setup then bump-up your gyro sensitivity (typically 50 or greater) in the radio to put the gyro back into heading-hold mode. You'll want to fine-tune your gyro sense in the field. Try increasing the gyro sense until you see some wag from the tail in hover then back it off some. That way you'll get a lot better tail authority.

[istandalone]

that's all pretty much what i thought, but i needed to hear it from someone else "just in case". with my 450 i screwed around with what held better, set up in rate mode and switch to hh or just center the slider and set in hh. in the end it held a little better with the slider smack dab in the middle. i'll go both ways and see what happens and post back. now, if i could do something about the 8" of snow we got last night and the 6" forcasted for tomorrow......

[Pinecone]

Also, as you flip the servo end to end, the direction of rotation doesn't change. I know this for sure, as I just flipped the servo on my EP8 tail and thought I would have to reverse and didn't. And after looking at it realized that as you flip end to end, the servo arm also flips over, so motion is the same.

The "normal" (Finless) way of setting up a 401 is to using rate mode, set the pitch slider in the center of travel and the limits sets to not bind. You should adjust the distance of the ball from the shaft on the servo to end up with the limit pot set to 80 - 100 for best performance from the gyro.

The put it in heading hold mode and go fly.

There is NO reason to set up rate mode, unless you want to fly in rate mode. And if you set up rate mode, you need to readjust the limit as otherwise it may bind in one direction of travel as you iwll have moved the center point.

With the 401 and the Trex 450, the best way to set up the gyro is the above method as the limited tail pitch slider range needs the limit set to max in both directions. Other gyros, that allow you to set the rate separately in each direction, can be set up for rate without losing performance.

But the above method will work on any heli.

[istandalone]

well, i feel like a complete Rtard now. thanks, pinecone! thinking about it, if you just flip the servo (but the output shaft is still facing the right side of the heli) front to back, yea, the servo still moves the same way when rudder input is given. duh!! i guess all this time off from work is making my brain atrophy. at any rate i maidened her today. whoo hoo! she flew on the first try, everything seems damn near perfect. although i had to dial in quite a bit of expo, .13 60/deg servos are pretty quick. too quick. but this thing is a very solid hoverer. i just had it out in the driveway so i couldn't do too much but i had to try it. now if this damn snow will go away and the temp rises by about 50f i'll be set. and as far as the gyro goes i just set up the tail slider centered and left it in hh. it was pretty windy, but it held great. i've got the limit on it set at about 140 with no binding, which seems high to me but i'm using the wheel that came with the servo (9254) so a smaller wheel will lessen the throw. i want to say thanks to everyone who answered my newb questions in the last few days, because without your help i'd still be setting it up. one more thing, has any of you had your two long black swash links hit the canopy when it's installed? i had to trim back about 8mm of the canopy for it to clear. seems my canopy was bent out of the box, so one side was closer to the head.

[mjdee14]

Had to trim my canopy on both sides a little..it cracked after a while and I fixed it with a small piece of white cloth...and thin ca....also fixed both grommet holes the same way....

[istandalone]

my canopy is cracking wicked easily. so tonight i mixed up some epoxy resin and brushed it around all of the edges on the inside of the canopy. the edges seem to be where the cracks start so that should hold it.

[mjdee14]

Originally Posted by istandalone

my canopy is cracking wicked easily. so tonight i mixed up some epoxy resin and brushed it around all of the edges on the inside of the canopy. the edges seem to be where the cracks start so that should hold it.

I did the same thing and it cracked again....I made a new repair with of all things...the elastic waist band form some old briefs....(underwear) it's streachy and it's thicker than regular material. i put done some tin CA and sprayed the material with kicker....."it will never crack" there again ! i also moulded it around the grommet holes..used regular material from briefs...drilled new holes in the material and now the grommets are stronger than the rest of the canopy. I have a couple of other canopies awaiting painting...and I might just do this before they crack.

[Pinecone]

Don't feel bad, I only know because I just went through it. It had me scratching my head a bit.

Epoxy by itself has little strength, you need to add some reinforcement. It can be as simple as some paper towel, or some light cloth, can be normal, or fiberglas, or etc. Kevlar would be perfect as it doesn't tear.

[istandalone]

i've got a bunch of kevlar at work, we use kevlar gloves. i guess i'll have to "liberate" a pair! thanks for the ideas. btw, does anyone know of a source i can get sheets of carbon fiber from?

[Happy|Harry]

Originally Posted by istandalone

i've got a bunch of kevlar at work, we use kevlar gloves. i guess i'll have to "liberate" a pair! thanks for the ideas. btw, does anyone know of a source i can get sheets of carbon fiber from?

have a look here

EBAY CF Sheet

phil

[Pinecone]

Cured or raw?

http://www.acp-composites.com/acp-cat.htm

http://www.cstsales.com/

[istandalone]

cured. on ebay it's all cf vinyl sticker sheets, i could not find a piece of real carbon fiber and i looked at 12 pages of crap! i'm looking to make a new battery tray for the 450 (trex style, slanted) and maybe a rx/servo lipo tray for the 550. so i'd probly want something 1/8" or close to it.

[Happy|Harry]

Originally Posted by istandalone

cured. on ebay it's all cf vinyl sticker sheets, i could not find a piece of real carbon fiber and i looked at 12 pages of crap! i'm looking to make a new battery tray for the 450 (trex style, slanted) and maybe a rx/servo lipo tray for the 550. so i'd probly want something 1/8" or close to it.

huh? i just double checked and 95% of the CF listed in the link i provided above is proper CF sheets in thicknesses varying from 0.5mm to 3mm, are you sure you used my link or did you just try looking through ebay yourself?

for what your intending to use the CF sheets for you wont need near 1/8 of an inch thick, in fact anything over 2mm thick sheets is just not needed, for instance the gaui CF frame is only 1.5mm thick

phil

[istandalone]

i didn't use your link, as it was ebayuk. i just searched "carbon fiber" and "carbon fiber sheet". no worries, though. i friend of mine works at a manufacturing plant in my town that produces cf bumper and fender panels for the new corvettes. he's telling me that i'll have more cf then i can shake a stick at by thursday.