SMALL - espritmodel.com SMALL - Telemetry SMALL - Radio
Reply
Thread Tools
Old Jan 21, 2012, 10:36 AM
Registered User
Germany
Joined Jul 2010
486 Posts
About the extended elevator horn when using a "bent snake":
One could use 100% servo travel and get the desired elevator throws by using a very short servo arm and a control horn attached underneath the elevator which would be the way to go if the snake didn't have any slack.

Unfortunately, there is always a little bit resulting in sloppy centering of the elevator. Now if you increase the length of the servo and control arms so as to maintain the ratio you had before all that happens is you increase the "snake travel" while its inherent slack remains the same. Logically, this reduces the effect of the snake's slack on the system making the elevator more precise. The long servo horn behind the elevator is ugly but very recommendable when you use a snake, especially a curved one. People don't do this to ailerons because they are not snake linked so there's no need.
Kwahn is offline Find More Posts by Kwahn
Reply With Quote
Sign up now
to remove ads between posts
Old Jan 21, 2012, 12:34 PM
Registered User
LVSloper's Avatar
Las Vegas
Joined Mar 2009
1,308 Posts
Quote:
Originally Posted by sebbe View Post
Mike, yepp, the rear wingbult is the way to go, I hate tape there..

Whats your setup ?
Sebbe, Im running a Neu 1115/1y 4.75x4.75 apc tp 4s 65c 2700mah; CC ice lite 100 esc; radio is a JR 9303. I decided to go bottom drive only, not planning on racing so I was not too concerned with the added drag. I used hyperion ds09-amd servos in the wing and a ds09-scd for the elevator. The AUW ended up at 40.5 oz.(lipo wt. 10.50oz.) with the CG at 57mm. This is my first electric F5D pylon and I really only picked up the plane to keep my thumbs in condition for DS during the off season. Fun plane; although; the desert is not too kind to hollow molded CF planes. I got some damage to the L.E. the other day and in the repair process now. Hopefully I can clean up the L.E. and get it back to a nice and clean airfoil again. Good luck with your build.

Best, Mike
LVSloper is online now Find More Posts by LVSloper
Reply With Quote
Old Jan 21, 2012, 04:20 PM
"The Judge"
sebbe's Avatar
Sweden
Joined Feb 2006
5,817 Posts
Ok, Mike, seems like a nice setup... ok so you bet up your Viper, thats bad, she is a real beuty. hope you fix it..

On launch, do you go full throttle, does the Viper torqueroll much ?
sebbe is offline Find More Posts by sebbe
Reply With Quote
Old Jan 21, 2012, 04:50 PM
Registered User
LVSloper's Avatar
Las Vegas
Joined Mar 2009
1,308 Posts
Quote:
Originally Posted by sebbe View Post
Ok, Mike, seems like a nice setup... ok so you bet up your Viper, thats bad, she is a real beuty. hope you fix it..

On launch, do you go full throttle, does the Viper torqueroll much ?
Yes, I go full throttle, not much of a torqueroll. The Aileron trim was a straight trailing edge; elevator was up about 1/2mm. I could moved the CG back some and try to get the elevator even with the stab, more concerned with making sure my repair job is clean for now. I used about 5mm/-3mm for ailerons; 29mm of flap; 4mm/-3mm elevator and about 3-4mm for spoilers. The elevator has about 3mm down when in full flap/crow mode. The plane can really be slowed down and does no have any bad stall habits.
LVSloper is online now Find More Posts by LVSloper
Reply With Quote
Old Jan 22, 2012, 02:10 PM
"The Judge"
sebbe's Avatar
Sweden
Joined Feb 2006
5,817 Posts
Quote:
Originally Posted by LVSloper View Post
Yes, I go full throttle, not much of a torqueroll. The Aileron trim was a straight trailing edge; elevator was up about 1/2mm. I could moved the CG back some and try to get the elevator even with the stab, more concerned with making sure my repair job is clean for now. I used about 5mm/-3mm for ailerons; 29mm of flap; 4mm/-3mm elevator and about 3-4mm for spoilers. The elevator has about 3mm down when in full flap/crow mode. The plane can really be slowed down and does no have any bad stall habits.
Thanks man.... 4mm/-3mm elevator sounds much ?? I thought it should be like +2/-1.5mm..
sebbe is offline Find More Posts by sebbe
Reply With Quote
Old Jan 22, 2012, 09:51 PM
Tim Lampe; Hobbico R&D
KRProton's Avatar
Champaign, IL
Joined Dec 2009
3,864 Posts
Okay, so I wanted to displace the elevator pushrod as far back in the vertical stab as possible to align it with the trailing edge of the elevator for the best servo resolution and mechanical leverage (as recommended by several of you on this thread.)

First, that meant grinding/sanding out some of the resin inside the fuse joining the trailing edges of the vertical. I used a combination of my Dremel with tiny cutting bits, sandpaper and a rat-tail file to remove enough of the resin to accomplish the task.

I then sanded down both sides of the pushrod guide tube to allow it to fit farther aft inside the vertical stab. I also switched from the oversize .032” K&S pushrod I was contemplating using to the .025” K&S pushrod wire (the kit comes with .023” pushrod wire).

Then, time to make my elevator horn. Working with carbon fiber is a messy (and potentially dangerous) proposition. BE CERTAIN TO USE GOOD BREATING FILTERATION! I started a slot in the carbon fiber, then cut the piece from the sheet. Next was to shape the slot to fit the elevator. I used the cutoff wheel, sandpaper, a razor saw and a small file. Once I got the “wedge” cut to fit the elevator, time to drill the hole. I used a .025” drill. But I found out drilling straight through carbon fiber is difficult – the very thin and “bendy” drill bit takes on a mind of its own and just angles through the material. After all the work I had done to fit the wedge to the elevator, the hole came out angled and the horn was useless! After a few more trial-and-errors, I learned that if you chuck the drill bit almost all the way down into the drill it won’t bend so easily and you can drill a straight hole (well, as straight as you can hold the drill). Time to cut another elevator horn!

This time I got it sanded to final shape and attached are images of the end result. The hole is behind the pushrod, so I made this little bend. Think that’s okay?

My next plan is to temporarily glue the horn to the elevator with RC-56 white glue, then continue on with the servo installation. After it’s all done and I have everything working the way I like, I’ll remove the horn and permanently glue it on with CA.

I’m thinking of using a quick shot of spray foam insulation to anchor the guide tube in the vertical stab.

When I make the removable elevator servo mount it’ll also hold my receiver battery and receiver.

Tim
KRProton is offline Find More Posts by KRProton
RCG Plus Member
Old Jan 23, 2012, 04:56 AM
"The Judge"
sebbe's Avatar
Sweden
Joined Feb 2006
5,817 Posts
Very nice, looks like mine, it will be perfect... Dont worry about the little bend, it will be good..
Its more important to make that plastic tubing sit tight on just about every place you can glue it..
sebbe is offline Find More Posts by sebbe
Reply With Quote
Old Jan 23, 2012, 01:08 PM
AEM
AEMontoya's Avatar
Bay Area, CA
Joined Sep 2009
1,039 Posts
The elevator horn setup looks good. The bend in the pushrod won't be a problem. One thing, though. Before gluing the elevator horn in place, I would connect it to the pushrod, as you did in your last pick, and move the elevator up and down across a range of about +4 to -4 to make sure that the pushrod it doesn't rub up against the pushrod sleeve where it exits the vertical stab. You probably already did this, but I thought I'd mention it just in case. Also, with the pushrod that far out behind the trailing edge, you won't be able to use a tiny servo arm in order to get the type of elevator deflection you'll need--just something to bear in mind when you make the arm. Looks like you already have every detail thought out really well, though.

AEM
AEMontoya is offline Find More Posts by AEMontoya
RCG Plus Member
Old Jan 23, 2012, 01:17 PM
Tim Lampe; Hobbico R&D
KRProton's Avatar
Champaign, IL
Joined Dec 2009
3,864 Posts
Thanks guys.

What I already did was temporarily glue the elevator horn to the elevator with RC-56 canopy glue. Then I can continue with the rest of the setup and make sure everything works the way I like. If I need to make a new horn I can still remove the one I already have and replace it.

Where do you think the pushrod should end up on the elevator? As close to the trailing edge as possible? I could make another horn with the hole moved forward 1mm or 2mm. Or, should it be under the elevator, but near the TE???

Thanks.

Tim
KRProton is offline Find More Posts by KRProton
RCG Plus Member
Old Jan 23, 2012, 02:16 PM
"The Judge"
sebbe's Avatar
Sweden
Joined Feb 2006
5,817 Posts
Tim, my horn is setup this way, look at my picture, i can move +4mm/-4mm with 90% travel, pretty good I think..

My elevator is stiff, no flex, 100.0% sloopfree...

I dont think its gonna be much better..

I drilled a new hole under the most inner hole in the servo arm, HITEC HS-65HB..

Just try wich hole to use in the servoarm to make the travel lika I have, then its all fine..



From what I can see, your horn looks like mine in shape and size, go for it, cant be much better..

Sebbe
sebbe is offline Find More Posts by sebbe
Reply With Quote
Old Jan 23, 2012, 04:49 PM
"The Judge"
sebbe's Avatar
Sweden
Joined Feb 2006
5,817 Posts
There will always be some error/wrong with a setup liknkage like this, due to the geometry and angle the elevator moves...

If you look at mine exit, the plastictube has a wider exit hole at the end, like a trumpet, not deep, but like 2-3mm depp, so the wire can move +-1mm at side when elevator moves +-4mm up/down.... Mostly when you fly you will use like +2 to +3mm up, then when the wire comes more depper into the tube, it will stabilze quick, there will be no flex or bending in this part... the flex will happen where the tube is straight and longrunning inside the fuse, there is where you have to glue the snake securem and also it has to be secured inside the fin, thats why I did dremel o small hole so I could put in epoxi to run along the snake..

IF you secure the plastic tube in as many places as you can all the way, except 15-20mm in the begining and 10mm in the end, you will have no slop at all... Like I said, my elevator feels like its secured with glue, that is how sloopfree it feels...

But of course, there is at least 10 ways to do this, the goal is to get it 100% sloopfree and the travel as close to 100% when moving elevator +-4mm, I think I have achieved it quite good.... SO dont worry, continue the way you are going now, and dont glue the last bit of the tube(10mm) in the end, leave it free, and make sure the wire can move sideways free without bending, otherwise you have to dremel away more material aft in the fin. and it will be perfect..

Sebbe..
sebbe is offline Find More Posts by sebbe
Reply With Quote
Old Jan 24, 2012, 10:51 AM
Tim Lampe; Hobbico R&D
KRProton's Avatar
Champaign, IL
Joined Dec 2009
3,864 Posts
Anybody got any problem with a HiTec HS-65HB on the elevator for the Viper?

I have a couple of Hyperion DS09's for the ailerons, but was thinking about the HiTec for the elevator (just because I already have one). The HiTecs are the ones that cured the aileron flutter on my Sunracer because of their precision - no gear lash/freeplay.

Tim
KRProton is offline Find More Posts by KRProton
RCG Plus Member
Old Jan 24, 2012, 11:22 AM
making my own planes...
decones's Avatar
Curitiba - Brazil
Joined Oct 2007
1,122 Posts
I was using it, HS65 for elevator, no dramas, fits perfect and ok.
Duo to arrange more space for my lipos I moved the servo far away back into the boom,
then I change it to Airtronics 809, just because I have it and it's digital, but the Hitec is OK too

Andre
decones is online now Find More Posts by decones
Reply With Quote
Old Jan 24, 2012, 04:42 PM
"The Judge"
sebbe's Avatar
Sweden
Joined Feb 2006
5,817 Posts
The hitec hs-65HB are 100% sloopfree, accurate and strong enough for elavator in a Viper, no problems Tim..... I would say they have less sloop in gear then Hyp 09 amd:s... So I cant see why Hyp 09 would be ok in elevator and hs-65HB not..

From what I have read so far (even though all my 09:s are fine so far) I would thrust hs-65 more then the Hyp 09:s for sure..
sebbe is offline Find More Posts by sebbe
Reply With Quote
Old Jan 24, 2012, 07:02 PM
Tim Lampe; Hobbico R&D
KRProton's Avatar
Champaign, IL
Joined Dec 2009
3,864 Posts
Thanks sebbe and decones!

Okay, pretty much settled on the elevator pushrod and control horn, now onto the servo/Rx/batery mount (radio tray)...

First I made a guide rail/U-channel from ply and basswood. Then I made a temporary, dummy template for the radio tray/servo mount to be used to position and hold the rails into position while the glue is drying.

The extended "tongue" aids in positioning and will be cut off after the rails are permanently installed.

Drilled holes through the center of the U-channel rails, then used those holes as templates to drill the screw holes through the top and bottom of the fuse.

Positioned the rails on the temporary radio tray, added glue, then positioned it in the fuse until the holes in the rails aligned with the holes in the fuse. Temporarily using tiny wood screws to center the rails while the glue dries.

Then, I'll extract the temp. radio tray and put in the real one to be held in with slick #2 button head screws.

Got my elevator servo mounted to the real radio tray with my Rx and Rx battery standing by.

Tim
KRProton is offline Find More Posts by KRProton
RCG Plus Member
Last edited by KRProton; Jan 24, 2012 at 07:31 PM.
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
New Product New Build thread for Viper F5D Model Rob AR High Performance 20 Sep 08, 2009 04:06 AM
Discussion new pylon model - Viper F5D 2009 MarkChinery High Performance 2 Mar 11, 2009 02:46 PM