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Old Feb 07, 2012, 02:20 PM
60 years of RC flying
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Canada, ON, Ottawa
Joined Feb 2006
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Originally Posted by justinspanier View Post
Perfectly said. This is my first delta plane, so I'm still in the process of learning the nuances of flying it. I also like to tinker with stuff just to see what happens (flaps,spoilers, etc.).

I usually like to mix a little rudder in with the ailerons, but after about an hour of flying this plane, I found that it seemed to fly better when I didn't mix in any rudder. Anybody else have any experience with this?
You should also try high alpha flying. Gradually pull lots of up elevator while reducing power, till you get to a state where it is flying nose high and slowly without losing height. At this point, the ailerons are mostly ineffective and it's mandatory to fly on rudder for steering. Eventually, you should be able to fly indefinitely with full up elevator while controlling climb and descent with throttle and steering with rudder. The model will at some point start a classic delta wing rock, which should be fully manageable.

To recover, just ease of the up and add power gently. It's all quite safe if done at altitude, but obviously it can get you quickly into trouble. So don't try it low down till you've had some practice.

Spoilerons give a kind of automatic high alpha, but the ailerons keep working quite well.

I tried mixing aileron to rudder and found it somewhat helpful during approach but the rest of the time you definitely don't want mixing. Nor do you want aileron differential.

If you like rolls and inverted, you need to set up the elevator with quite a bit more down than up, as with the stab at -2 degrees, the first part of down throw is used up just compensating for the built-in up. I typically set the endpoints at 85% up and 110% down, or something like that. You may also find that you want less expo in the down direction (not all transmitters can do this).
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Old Feb 07, 2012, 02:24 PM
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Originally Posted by Daedalus66 View Post
You should also try high alpha flying. Gradually pull lots of up elevator while reducing power, till you get to a state where it is flying nose high and slowly without losing height. At this point, the ailerons are mostly ineffective and it's mandatory to fly on rudder for steering. Eventually, you should be able to fly indefinitely with full up elevator while controlling climb and descent with throttle and steering with rudder. The model will at some point start a classic delta wing rock, which should be fully manageable.

To recover, just ease of the up and add power gently. It's all quite safe if done at altitude, but obviously it can get you quickly into trouble. So don't try it low down till you've had some practice.

Spoilerons give a kind of automatic high alpha, but the ailerons keep working quite well.

I tried mixing aileron to rudder and found it somewhat helpful during approach but the rest of the time you definitely don't want mixing. Nor do you want aileron differential.

If you like rolls and inverted, you need to set up the elevator with quite a bit more down than up, as with the stab at -2 degrees, the first part of down throw is used up just compensating for the built-in up. I typically set the endpoints at 85% up and 110% down, or something like that. You may also find that you want less expo in the down direction (not all transmitters can do this).
I'm going to change my flapperons up to spoilerons and set everything like you said here and go for it..
Thanks for the wisdom
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Old Feb 07, 2012, 03:35 PM
60 years of RC flying
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Canada, ON, Ottawa
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Originally Posted by pecanpatch View Post
I'm going to change my flapperons up to spoilerons and set everything like you said here and go for it..
Thanks for the wisdom
Let us know how it goes. I have mixed feelings about the spoilerons but had an interesting time experimenting with them.

The other thing you can do, if your transmitter allows it, is to use the ailerons as elevons and link to elevator, so ailerons go up when elevator goes up. This adds to control power, and some people swear by it.

Note that this is the opposite of what is done with conventional models when flaps are linked to elevator. In that case, the flaps go down for more lift when elevator goes up to increase angle of attack. Here, the flaps/ailerons are going up to reinforce elevator action. The difference is that on a delta, the control surfaces are well behind the CG and thus have lots of moment arm to work with. This is one reason why flaps are not very effective on a delta (and generally aren't needed).

All sorts of things to experiment with if you install two aileron servos. On the other hand, I don't think any of them really make the Polaris fly better, just different. But that's a matter of taste, I guess.
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Old Feb 07, 2012, 04:17 PM
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Originally Posted by Daedalus66 View Post
Let us know how it goes. I have mixed feelings about the spoilerons but had an interesting time experimenting with them.

The other thing you can do, if your transmitter allows it, is to use the ailerons as elevons and link to elevator, so ailerons go up when elevator goes up. This adds to control power, and some people swear by it.

Note that this is the opposite of what is done with conventional models when flaps are linked to elevator. In that case, the flaps go down for more lift when elevator goes up to increase angle of attack. Here, the flaps/ailerons are going up to reinforce elevator action. The difference is that on a delta, the control surfaces are well behind the CG and thus have lots of moment arm to work with. This is one reason why flaps are not very effective on a delta (and generally aren't needed).

All sorts of things to experiment with if you install two aileron servos. On the other hand, I don't think any of them really make the Polaris fly better, just different. But that's a matter of taste, I guess.
I once again had an Elev to Aileron Mix setup on the Gear switch for Vectaris but I had it switched OFF for the test flight. After the first pack and some changes to bring the Expo way down, I found myself turning the mix ON and ahhhh I've got my Polaris(Vectaris) back again. I think what happens is that during the flare I not only get assistance in pitch from the ailerons but the up-going ailerons help 'dump' lift a little and ensure touch down is stay down. Maybe it's just that I always fly with this mix ON and I need the response it gives? Who knows.
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Old Feb 07, 2012, 05:15 PM
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D66
What you said about ailerons (ie acting as flaps) together with elevator deflections I find interesting. When flying full size aircraft we always lower the nose, ie ease the stick forward, as we lower the flaps and vice versa, never do we do we pull back on the stick as we lower the flaps. I have never used flaps on a model as I can see no value in having them.
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Old Feb 07, 2012, 06:41 PM
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The large delta wing of the Polaris means that the ailerons can't act as "flaps" per se. To call them either flaperons or spoilerons is really not correct.

They're elevons, either mixed with the conventional elevator or not. This is proven by the fact that modified Polari have been flown with no stab installed at all. Something you wouldn't try on a "flaperon" ship.

(They fly better with the stab, in partly due to the incidence compensating for the high thrust line and partly due to the added control authority from the propwash overthe elevator, but they'll fly OK without it.)

You can mix the elevons to assist the elevator, or you can mix them to fight it. Most people seem much happier with the results when they work together.
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Old Feb 07, 2012, 06:46 PM
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Originally Posted by acecall View Post
D66
What you said about ailerons (ie acting as flaps) together with elevator deflections I find interesting. When flying full size aircraft we always lower the nose, ie ease the stick forward, as we lower the flaps
For level flight or landing approach, a typical flap equipped model will do the same. Down elevator is always mixed with down flap. The down angle on the fuselage during some flapped landings can be quite striking.

D66 is referring to the way some aerobats will mix down flap with up elevator (note the reversed order) in order to get a sharper pitch response. In soaring we call it "snap flap," and some guys use it to make a more efficient race turn.
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Old Feb 07, 2012, 10:39 PM
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Canada, ON, Ottawa
Joined Feb 2006
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The ailerons on the Polaris can certainly function as flaps, since Polaris has a stabilizer to counteract the nose down pitch produced because they are far aft of the CG.

The point really is that you don't need or even want the extra lift generated by adding camber to the airfoil (which is what flaps do). The Polaris has very light wing-loading and the issue on landing is how to get rid of speed and lift. So the useful part of drooping the ailerons is not the lift but the drag. Because the ailerons also have elevator (elevon if you like) power, they produce nose down pitch that has to be compensated for by holding up elevator or using a mix. You might say that the down aileron/up elevator situation is a bit like crow on a glider.

Raising the ailerons also produces drag, but it reduces lift. As well, it has an up elevator action, so the nose tends to pitch up. This is troublesome if you are going fast but fine if you get slowed down first. On the Polaris, it's quite a stable and easy to fly mode. Just go easy on the throttle! I even allowed the XL a couple of times to make hands-off landings from a considerable height in this spoileron mode.

The use of coupled flaps and ailerons on models goes back to the 1940 and 50s, when control-line stunt models (like the classic Nobler) used flaps to increase lift while the elevator managed pitch. So the flaps went down when the elevator went up, This produces very sharp turns, as required for "square loops" and the like. This is the same "snap flap" action that rdeis is referring to.

This is NOT how flap and elevator can be coupled on a Polaris. Instead, if you want increased control action, you need both the ailerons and the elevator going up at the same time. Both are doing the same thing, controlling pitch. That big delta wing can generate all sorts of lift if given enough angle of attack. That's the action nr2go is talking about. I suspect he's right about the up aileron reducing lift and helping the landing but I'm not sure how big an effect it is.

By the way, the question of whether flaps on a more conventional aircraft (more or less straight wing) cause nose up or nose down trim depends of which aircraft you fly. The Spitfire, for example, and many other such aircraft, had a strong nose down pitch when flaps were lowered and required up trim. My recollection of flying a Cessna 172, however, is that, as acecall says, it required nose down trim. Certainly with models, the best advice is simply to be careful the first time you deploy flaps on an unknown model because you don't know which way the trim is going to change.
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Old Feb 08, 2012, 12:59 AM
Radian, Polaris, Mistaken ID.
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Japan (Military)
Joined Nov 2010
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Great Mods!

Wow!! Love all the great mods guys... Custom Canopies, Flaps... and especially the thrust vectoring!!! Great job guys. Inspiring. Makes the build I am working on n0ow seem a little boring.

Keep up the good work! I am feeling inspired to do something different myself.... Have to look around the hobby room and see what is laying around!

I was just happy my Polari is coming out so clean!

I did expand the plate under the Nacelle since I had some .5 CF laying around!
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Old Feb 08, 2012, 01:49 AM
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Originally Posted by Baseman View Post
Wow!! Love all the great mods guys... Custom Canopies, Flaps... and especially the thrust vectoring!!! Great job guys. Inspiring. Makes the build I am working on n0ow seem a little boring.

Keep up the good work! I am feeling inspired to do something different myself.... Have to look around the hobby room and see what is laying around!

I was just happy my Polari is coming out so clean!

I did expand the plate under the Nacelle since I had some .5 CF laying around!
Nice clean build so far, looking good. I like what you've done inside the aft section in creating a cable channel down the side. How are you going to do the ailerons? Will the pieces that form the channel get in the way? The expanded plate will help distribute the loads, but probably isn't necessary if you were trying to keep the wt down. Keep up the good work, pics are always welcomed.
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Old Feb 08, 2012, 02:27 AM
Radian, Polaris, Mistaken ID.
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NRG2GO

Thank you for your comments. I was getting back on here to specifically comment on your Vectaris!

First your questions...

I plan on doing the ailerons on top of the wing like Scotts Planes from Model Aero. My first Polaris I did as per the original plans. I found the rear bottom compartment to be very crowded. Also putting all electronics above the wing (And above the water line) Now only have the Rudder Servo face down and aileron servo on top. They are out of each others way. I will post more pictures soon. Notice I also used Kadils idea for the motor connector. My last one I simply glued the connectors out the bottom of the neceille.. It looked rough... Right after finishing that I seen Kadil post his...

I have been following this thread since I got on RCG. I was inspired to scratchbuild by the Polaris. (I am working on #3) I have to say your work with the vectaris is one of the most impressive things I have seen on this thread!!! Not only did you make thrust vectoring.. You made the stab movable also... not just the motor!! Throw on top of that the fact that you can break it down for easy transport!!! And the whole thing is a clean build!

Brilliant!!!

I am curious as to how you "Locked" the wings on.... (For lack of a better word) And am curious also how the mechanics in your vectoring work??

You, Steve, D66, Scott, Kadill, and everyone else who contributes.... Both triumphs and failures..... (I can learn from others mistakes and mistrials) Make this a great Thread to learn about more than just the Polaris !!





Quote:
Originally Posted by nrg2go View Post
Well I have been very quiet on the thread of late. The reason is because I have been working on an idea and that idea was Test Flown this morning.

This idea introduces two main concepts and a third which I am currently modifying as it didn't come up to my expectations.

I will post this video first and let it speak for itself. Then I will followup with some pic's. I'll leave the finer detail of how and what for questions if anyone is interested.

Enjoy

http://vimeo.com/36183408
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Old Feb 08, 2012, 02:59 AM
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Australia, NT, Katherine
Joined Apr 2009
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Originally Posted by Baseman View Post
NRG2GO

Thank you for your comments. I was getting back on here to specifically comment on your Vectaris!

First your questions...

I plan on doing the ailerons on top of the wing like Scotts Planes from Model Aero. My first Polaris I did as per the original plans. I found the rear bottom compartment to be very crowded. Also putting all electronics above the wing (And above the water line) Now only have the Rudder Servo face down and aileron servo on top. They are out of each others way. I will post more pictures soon. Notice I also used Kadils idea for the motor connector. My last one I simply glued the connectors out the bottom of the neceille.. It looked rough... Right after finishing that I seen Kadil post his...

I have been following this thread since I got on RCG. I was inspired to scratchbuild by the Polaris. (I am working on #3) I have to say your work with the vectaris is one of the most impressive things I have seen on this thread!!! Not only did you make thrust vectoring.. You made the stab movable also... not just the motor!! Throw on top of that the fact that you can break it down for easy transport!!! And the whole thing is a clean build!

Brilliant!!!

I am curious as to how you "Locked" the wings on.... (For lack of a better word) And am curious also how the mechanics in your vectoring work??

You, Steve, D66, Scott, Kadill, and everyone else who contributes.... Both triumphs and failures..... (I can learn from others mistakes and mistrials) Make this a great Thread to learn about more than just the Polaris !!
Thanks Baseman,

I used Aus as a sounding board for a lot of Vectaris and he had to keep it under his hat the whole time. There is a lot of retired guys who I thought would take my idea over the line before I could so I kept it secret.

You will find that I am adding all the detail slowly to my blog. There is one entry for Vectaris but you have to scroll down a little and click on the comments for it to see all the detail. As I said I am slowly adding detail and if there is something I haven't covered just post a question and I will expand.

To answer you here and now both the wings and the stabs are held in place purely from the friction of the spars. The stabs actually have some magnets that mate with some on the Nacelle sides for extra insurance. But let me tell you that I haven't installed the magnets for the wings yet and after 6 flights last Sat the wings did not move 1mm. I have the magnets in the wing roots but haven't installed the corresponding magnets in the fuselage side. Given the wing has two spars and under flight load I would defy anyone to try and slide them outwards anyway.

Anyway go have a read, and I'm happy to take more pics/vid to show any detail anyone thinks they would like to see.

Cheers
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Old Feb 08, 2012, 03:14 AM
Tony Audsley Retired Locksmith
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Very clever things you have done there Nrg2go

I too would like to see how you did the wing and tailplane and how you hooked up the ailerons etc .. any pics?

Great mods mate, keep up the GREAT work

Baseman … nice looking build mate .. keep the pics coming

Lockey
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Old Feb 08, 2012, 03:33 AM
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Originally Posted by Lockey View Post
Very clever things you have done there Nrg2go

I too would like to see how you did the wing and tailplane and how you hooked up the ailerons etc .. any pics?

Great mods mate, keep up the GREAT work

Baseman nice looking build mate .. keep the pics coming

Lockey
Hey Lockey,

I won't clutter the Polaris thread at the moment. Click on my name 'nrg2go' and it will take you to my blog. Vectaris is the latest entry, so its at the top. Scroll down to the bottom of the Vectaris entry, not the bottom of my blog, and click on comments to see more detail. I am still adding more but if there is something you would like to ask or see thats not already covered just post a comment in there.

Cheers mate.
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Old Feb 08, 2012, 08:01 AM
Tony Audsley Retired Locksmith
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Thanks nrg2go, good info mate, great blog, I might just look at something like that for my XL when I build it

Lockey
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