Nothing too crazy, but I'm building my first scratch glider. Here's my build thread/advice thread.

[UCChris]

Building a scratch glider for slope. Just mocked it up this morning and starting to work on the wing. I wanted to get some advice on the setup.

60" wingspan
48" fuselage
Leading edge of the wings set 10" back from nose

Does that seem like a reasonable setup?

Also, what are the dimensions of the slots that FT uses to stick in their 9 gram servos?

Also, is it okay to build a glider with ailerons only and mix them to be elevons?

Here's a pic of what the ratio of wing/fuselage looks like.

 

[Hai-Lee]

Building a scratch glider for slope. Just mocked it up this morning and starting to work on the wing. I wanted to get some advice on the setup.

60" wingspan
48" fuselage
Leading edge of the wings set 10" back from nose

Does that seem like a reasonable setup?

Also, what are the dimensions of the slots that FT uses to stick in their 9 gram servos?

Also, is it okay to build a glider with ailerons only and mix them to be elevons?

Here's a pic of what the ratio of wing/fuselage looks like.

As for a reasonable setup, Almost anything similar will fly and if the weight is low and the balance correct it will glide quite well.

The servo slot size is something I never worry about I just leave the servo slot cutting until I work out where the servos are to be fitted to give the proper balance and then I just run a pencil around the actual servo and then cut out the hole in the FB to suit.

The use of Elevons ONLY on a conventional aircraft layout may give slow control response, in pitch especially, as the horizontal stab tends to become the determining factor on the centre of pitch rotation. In the extreme the plane may seem to want to pitch using the tail as the centre of the pitching moment.

For better control you could consider making it a flying wing, (tailless), a canard, or fit a functioning elevator and mix a little elevator into your aileron channel.

Have fun!

 

[UCChris]

Thank you for the help Hai-Lee. I was worried about the elevator thing. I'm hoping it won't be an issue because I personally find that I don't use as much elevator slope soaring as I do regular flying, so we'll see.

I got the wing done, now working on the 3d printing of the wing bracket and tail bracket. I'm not terribly happy with the shape of the airfoil, but live and learn.

 

[foamtest]

I would still recommend making a separate elevator control, it may not seem like your using much until it’s gone. If you put the “elevator” on the wing it will just act as flaps or spoilers ( I think that’s what they’re called). I don’t think it would have enough leverage to control the plane. Also I would move the wing back a little unless you’re using a giant battery to balance this. Just some recommendations from what I saw.

 

[UCChris]

I would still recommend making a separate elevator control, it may not seem like your using much until it’s gone. If you put the “elevator” on the wing it will just act as flaps or spoilers ( I think that’s what they’re called). I don’t think it would have enough leverage to control the plane. Also I would move the wing back a little unless you’re using a giant battery to balance this. Just some recommendations from what I saw.

Thank you for the advice. I am currently designing a way to mount a functional elevator to make it a standard bank and yank.

 

[Grifflyer]

I agree with foamtest move the wing back a little bit that'll make balancing it out a little easier.

But so far the wing looks pretty good, and do you plan on having any sort of flaps/flaperons?

 

[UCChris]

I agree with foamtest move the wing back a little bit that'll make balancing it out a little easier.

But so far the wing looks pretty good, and do you plan on having any sort of flaps/flaperons?

How far back should I move the wing?

I have the ailerons. I was just going to mix the ailerons to make flaperons. Is that okay?

 

[Grifflyer]

How far back should I move the wing?

I don't know exactly, but have it so it looks something like this.

I have the ailerons. I was just going to mix the ailerons to make flaperons. Is that okay?

Yes, that'll work great!

Good luck,
Grifflyer.

 

[UCChris]

Not much progress these last couple days. Waiting to have the money for the main CF tube for the fuselage and for my buddy to print the mounting brackets I designed. Did put a carbon fiber tube as a support strut in the wing. Wing all up weighs exactly 11.5 oz.

 

[UCChris]

Question about v tail vs standard t tail. V tail is going to be way easier for me to put on the plane, but I've heard that they aren't great for rolls. However, I don't really plan on doing many rolls with this plan since it's a sloper.

 

[Grifflyer]

Question about v tail vs standard t tail. V tail is going to be way easier for me to put on the plane, but I've heard that they aren't great for rolls. However, I don't really plan on doing many rolls with this plan since it's a sloper.

A V-tail isn't designed to control roll it controls pitch (elevator) and yaw (rudder) authority. I know that just from looking at it that if you land in tall grass the leading edge of the tail won't get dinged up as much as a traditional tail would, and I'm going to guess that because there are two control surfaces moving there could be a bit more drag, but I'm going to go ahead and say that this is going to be more of a fun flyer and not so much a competition plane. I have also heard that angle of the tail will change how much authority the tail has. You could probably tune this quite simply because I think that the shaper the angle is (the closer the two sides of the "V" are to vertical) the more rudder authority you are going to have, and the shallower the angle is (the closer the two sides of the "V" 180 degrees) the more elevator authority you are going to have.

 

[Fluburtur]

Most V-tails have an angle of about 110°, from my experience they work quite well but standard ones cause adverse roll when you yaw, however inverted ones add roll in the direction of the turn but if you make it do only pitch it will be fine, they are also used in some racing rc planes because they actually reduce drag because the overall surface of the tail is a bit smaller.

 

[Hai-Lee]

Question about v tail vs standard t tail. V tail is going to be way easier for me to put on the plane, but I've heard that they aren't great for rolls. However, I don't really plan on doing many rolls with this plan since it's a sloper.

A LARGE V tail will make axial rolls difficult but otherwise they have no serious effect upon your ability to roll your glider.
As long as you know how to design for the "Effective rudder and elevator sizes" you should be fine.
V tails have a minor drag advantage and a serious advantage when it comes to landing as the tail surfaces are unlikely to ever contact the ground unless you crash.

If you need help just post, (ask).

Have fun!

 

[UCChris]

Thanks guys! I don't know know why I thought it would ruin the roll when I'm building a bank and yank... Stupid question!

Since this is just a fun flyer, I think the durability aspect is a definite yes for me. And since I only need it to run elevator, it should be easy to implement!