V-Tail Cunstruction Articles

[condor-60]

......Anyone recall seeing any step by step construction articles on converting
a glider to V-Tail configuration. I would like to try out a V-tail on my Floater
G-110 fuselage.

Thanks
Condor-60

[Mtntop]

If you are needing info to properly size it from a regular stab/fin to v then check the CRRC website then click on "old site" in the upper right corner then scroll down to aircraft designing. Find it.

[OVSS Boss]

Don Stackhouse might also have info on that. My thought though, big wings and v-tails with no ailerons are usually a disappointment.

Marc

[jcyr1]

Condor-60

[jcyr1]

Condor-60
OOps!!!! Do a search for CloudyIFR. He has a great XLS program for doing all the number crunching. Can't remember his website offhand, but worth the search.
John

[jcyr1]

Condor-60
Found the link: www.h1.ripway.com/cloudyIFR/index.html. Look for R/C Model Files.
John

[condor-60]

.......Guys I don't need number crunching as I can get that. I just need construction
articles,pictures and techniques. Thanks to all so far that responded.

Condor-60

[tinkrerpilot]

Condor-60,

Simple enough for the Floater. Add 2 inches to each side of the original stab plan. Cut it down the middle. Bevel the edges for 100 degree v. Knock the rudder mount off the top of the boom and use the exsisting stab mount. Center the V into the stab mount , add some triangle blocks on both sides. controls rods thru the original slots in the fuse boom with ball links on the ends to the elevators. Pretty straight forward.
Flew mine for 13 years that way. Sorry I sold it off, now.

[Don Stackhouse]

Don Stackhouse might also have info on that. My thought though, big wings and v-tails with no ailerons are usually a disappointment.

Marc

As far as sizing, just make the total area (NOT the projected area!) the same as the original tail. The common (but totally erroneous) practice of trying to make a V-tail have the same projected area as the tail it's replacing is almost singlehandedly responsible for the unfair reputation V-tails have often been saddled with.

There are a number of articles in the "Ask Joe and Don" section of our website www.djaerotech.com that discuss design and sizing of V-tails.

As far as "usually a disappointment", I beg to differ. If the tail is sized right, there is no problem, big wing is no more of a challenge than a small one. A properly sized V-tail should have essentially the same characteristics as the equivalent conventional or T-tail.

As far as structure, you can cut off the old tail mount and replace it with a saddle on top of the tail boom for the new V-tail, but another approach that usually works as well or better is to mount the tail on the underside of the tail boom, so the end of the boom nestles down into the notch formed by the tail panels. This lets it act as a structural reinforcement for the tail's dihedral joint, as well as an aerodynamic fillet.

[PeterH]

Mr. Stackhouse gave all the advice that's needed. To add a bit of (probably unnecessary) detail, if the original horizontal stabilizer/elevator had 150 square inches of area and the vertical stabilizer/rudder had 100 square inches of area, then the v-tail needs to have 250 square inches of area.

I've built mine at 110 degrees, having no better idea, and then found that Hobby Lobby sells control horns meant to be put on 110-degree v-tails. I've also built my v-tail fuselages so that the pushrods come straight out the back and the rear of the fuselage is aligned with the hinge joint on the v-tail.

[Don Stackhouse]

The angle required depends on the relative sizes of the equivalent horizontal and vertical tail surfaces. There are two different approaches, linear vs. squared, depending on whether your defining factor is tail authority (based on tail stall), or based on stabilizing effect. In general, longer, higher aspect ratio wings need more tail dihedral, while lower aspect ratio wings need less.

There are some articles in "Ask Joe and Don" that go through the details:

http://www.djaerotech.com/dj_askjd/dj_questions/vtailvolumn.html

http://www.djaerotech.com/dj_askjd/dj_questions/chrys_vtail-angle.html

The actual formulas for calculating the required tail dihedrals for the two approaches are here:

http://www.djaerotech.com/dj_askjd/dj_questions/vtail-formula.html

There are a number of other articles in AJ&D that discuss V-tail design. Just type "V-tail dihedral" or "V-tail sizing" into the search engine on the opening page of AJ&D, and it will come back with a list of url's for those articles.

[Thermaler]

As far as "usually a disappointment", I beg to differ. If the tail is sized right, there is no problem, big wing is no more of a challenge than a small one. A properly sized V-tail should have essentially the same characteristics as the equivalent conventional or T-tail.

Me and my 173" Super Esprit agree with Don. :D

Joe

[Crashmo1]

Condor,

All of these guys know way more than I do, I'm sure. Nonetheless, here is my input.
I decided to throw a V tail on a glass fuse 2 meter that didn't have any name or instructions, etc.
I worked with XFLR5 a bunch and 2 MS excel files on V tail sizing and conversion. I cannot upload MS files here. If you PM me I'll get your email and send them to you that way. The articles Don has are excellent. The MS files just do all of the algebra for you.
The only thing I noticed about my particular 2 meter was that rudder effectiveness was low at the common 110 degree spread. I moved it to a 100 degree spread and it was fine.
The photos are something I found somewhere a long time ago. It's just info to help your decision of how to attach the V tail.
I did mine with carbon tube spars that fit inside carbon tubes which are epoxied into the fuse. That way I can remove them for transport. I'll post photos of those later today if I remember. If you don't see them, PM me and I'll get on it.

[Crashmo1]

HI Berry,

This is the only way I knew to get you the photos. I can't attach anything in the pm.

I used a laser level to align everything. I even set the decalage angle at zero this way.

The XFLR5 program showed better dynamics with a +.5 or +1 degree incidence angle on the wing. I'll change that in the wing mount as needed so I can experiment with many angles.

This is a small diameter tail section and I spooged a bunch of epoxy in there to hold the tubes so I'll have to drill through that to run my pushrods.

Bill