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Flaps and slowing this thing down

Old 03-18-2010, 03:09 PM
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mooseflier
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Default Flaps and slowing this thing down

Hi, I have a 40 size super sportster with an OS 46 abc in it. The plane is pretty fast, which I want, but it's like landing a lawn dart with a rocket on it. I have a DX7 raidio that has flap capability, so I started looking at that as a way of slowing it down for landing. I would assume this is a good idea...?

The question I have though, is can it be configured if I'm using a Y harness for the two aeleron servos? I can't seem to get it to work... as the aelerons go opposite directions when using the flaps on the radio. I can get it to work if I hook them up individually to the receiver, and then make one of them (say aux) a slave of the other servo, but this would require me to buy a new extension for both servos. I know that's not a whole lot of money, but I would like to avoid buying more stuff if I don't need to. So I'm wondering if anyone knows how to do it with a Y harness that wouldn't involve reversing one of the servos.

Also, any other advice for slowing the plane down? I've heard that using a triple prop could help as well.

Thanks for any help!
Old 03-18-2010, 03:35 PM
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carrellh
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Default RE: Flaps and slowing this thing down

You can't have flaperons unless you get rid of the "Y" and run the ailerons on two channels.

A three blade prop may or may not help. A bigger two blade, with less pitch, might be a better alternative.

Which OS 46 do you have? FX, AX, LA?
What prop are you currently using?
Old 03-18-2010, 03:36 PM
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ChuckW
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Default RE: Flaps and slowing this thing down

Unless you install actual flaps and add servos for them, you will have to use the ailerons as flaperons. Most computer radios have this mix function in their programming. That being said, I wouldn't do them, especially on a Super Sportster. For one reason it just doesn't need them. Secondly it could create some negative characteristics that you just don't want like a nasty stall tendency.

I've built and flown kit and ARF versions of this airplane in both the .40 and .60 size. All were fast and agile. The .60 was a little heavy so it did come in a little hotter than the .40 but neither was what I would consider too fast to land. In fact, the .40 slowed down very nice. I always land them on the mains and let it roll out a little before it drops down on the tail wheel.

What prop are you using? How is the idle speed on the engine? It might just take some practice on setting up the approach to get it slowed down. I had the same problem with my .40 size GP Revolver at first but I eventually figured out how to get the airspeed and landing technique right.
Old 03-18-2010, 04:13 PM
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Default RE: Flaps and slowing this thing down

I agree with chuck here-I think your problem is approach. If you cut throttle to idle and glide long enough-it will stop flying and fall out of the sky, you just need to time it so your only 1/2" off the ground well you get my point. Also check your balance, make sure your not real nose heavy, that plane should land easy.
Old 03-18-2010, 04:19 PM
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Villa
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Default RE: Flaps and slowing this thing down

Hi mooseflier
Do you have much R/C airplane experience? Do you fly at a club where others can advice you? None of my plane have ever had flaps. I can slow every one of my planes till they literally dropout of the sky. Of course, it is best to be either very high, or just a few inches above the ground when that happens. Generally speaking, R/C models do not need flaps to slow down. I hope such a "broad" statement does not bring the house down on me. If you know how to fly R/C, then you should know how to slow the plane down for a landing. A low idle, up elevator, and lots of experience is all that is needed.
Old 03-18-2010, 04:36 PM
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ChuckW
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Default RE: Flaps and slowing this thing down


ORIGINAL: frenchie79
Also check your balance, make sure your not real nose heavy, that plane should land easy.
Good point, nose-heavy airplanes sometimes tend to come in a little hot.
Old 03-18-2010, 06:53 PM
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Default RE: Flaps and slowing this thing down

Personally, I'd use spoilers. Set a Flaperon wing type, then mix throttle as master & flaps as slave. Set the "flaps" to move up about 15-20 degrees at idle. They'll be in normal flight position at half throttle.

I use this set-up on everything except scale planes. Works great for spot landings.

Balance your Super Sportster on the main spar.
Old 03-18-2010, 08:19 PM
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Default RE: Flaps and slowing this thing down


ORIGINAL: Ed_Moorman

Personally, I'd use spoilers. Set a Flaperon wing type, then mix throttle as master & flaps as slave. Set the ''flaps'' to move up about 15-20 degrees at idle. They'll be in normal flight position at half throttle.

I use this set-up on everything except scale planes. Works great for spot landings.

Balance your Super Sportster on the main spar.
Now you mention scale planes!!!! I did that set up on one of my extras and it scared the peewaddle out of me the first time I used it. Can't say I wasn't able to spot land it from way up high but wow!!!! I can't sit at a computer long enough to read the new on line RC Report so I am really missing your stuff Ed. Any new stunts you came up with for us nimrods?? Gene
Old 03-19-2010, 02:08 AM
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mooseflier
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Default RE: Flaps and slowing this thing down

Thanks for the replies! I'm sure you guys are right in that I need more practice. I flew for the first time in about 15 years last weekend... was anxious, and had two or three landings that were rather speedy. The day was also during dusk, windy, and drizzling (live in Seattle). My approaches were fairly high up, as Ididn't want to take a chance on skimming the tall grass/weeds.

I think I'm also just looking for an excuse to use flaps. =) This is the first radio i've ever had with more than 4 channels... so fancy and all. The idea of the flaps are neat. So I'll work on my approach hopefully this weekend, and save the flaps for toying around with.

I'm curious though now that I have it set up and got the servo extensions I need to seperate them... for flaperons, do you make the aelerons go up or down? In planes that I've flown in (747s and such), the flaps always go down, but someone above mentioned that they should be set to go up.

The plane is balanced on the spar when the tank is full, so it shouldn't be nose heavy really. Though, I had to add about 7 or 8 ounces to the nose to get it that way! For some reason it was rather tail heavy. My guess is it's due to the elevator servos. I mounted two mini servos just in front of the stabalizer's leading edge in the firewall, one for each elevator half. I've always hated split elevators with a four-channel radio, so I put some servos in the tail to make the elevator rock solid.

Thanks again for the advice!
Old 03-19-2010, 02:50 AM
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mooseflier
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Default RE: Flaps and slowing this thing down

Oh, about the prop, I trashed it and can't remember exactly what it is. But now I have an Evolution 11x7. The other prop was definitely shorter.
Old 03-19-2010, 07:54 AM
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MikeL
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Default RE: Flaps and slowing this thing down

Always balance with the tank empty, unless your tank is behind the CG.
Old 03-19-2010, 10:25 AM
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ChuckW
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Default RE: Flaps and slowing this thing down


ORIGINAL: mooseflier
I'm curious though now that I have it set up and got the servo extensions I need to seperate them... for flaperons, do you make the aelerons go up or down? In planes that I've flown in (747s and such), the flaps always go down, but someone above mentioned that they should be set to go up.
Flaps generally do go down. They are also generally dedicated surfaces on the inboard portion of the wing. The problem with using the ailerons as flaperons is that it creates wash-in toward the tip of the wing (someone correct me if I am wrong). This could create a situation where the wing tip stalls easily or cancels out any beneficial wash-out that may have been put into the wing intentionally.

What Ed Moorman was referring to is using the ailerons as spoilers by deflecting both upward. He can elaborate on them much better than I can and explain why they are sometimes used and how they work. I've personally never tried them but I might one of these days.

Doing flaperons/spoilerons should just be a mix in your radio. You need to used dedicated channels for each aileron servo rather than a Y-harness then just program the function. Your DX-7 manual should explain it.
Old 03-19-2010, 11:51 AM
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Default RE: Flaps and slowing this thing down

ORIGINAL: MikeL

Always balance with the tank empty, unless your tank is behind the CG.
That is a very important advice!

Also, try to reduce the range of the acceptable or designer recommneded CG location.

Leave ailerons being just ailerons.

Spoilers kill lift, their use is like shopping off half of the wings in the air.

Flaps have the opposite effect, increasing lift and drag, and reducing the speed you can reach with no stall.

I recommend much practice and experienced company while you fly.

If you insist on flaps, a split flap will be easy to add and experiment with, without major surgery of the model.

http://en.wikipedia.org/wiki/Flap_(aircraft)
Old 03-19-2010, 01:58 PM
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mooseflier
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Default RE: Flaps and slowing this thing down

Hmmm I always thought CG was test with the tank full. I'll very likely be nose heavy again if I check it empty (cant' right now as I'm at work). But I guess I'll just have to add more nose weight. It's odd, cause I had 3 people out at the airfield look it over before I flew it and they all asked if the tank was full when they were checking CG (which it was).

Bummer about the flaps =( ...sounded fun. Maybe I'll set them up later, but only with a tiny tiny bit of down flap at max.

Thanks for all the advice!
Old 03-19-2010, 03:40 PM
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Default RE: Flaps and slowing this thing down

You check it with the tank empty because as you fly and the fuel is expended, your CG will keep moving further aft.  That can create a very bad situation.

Your Sportster will slow down nicely without flaps.  Just let it.  Practice slowing it down a few mistakes high, with the intent of becoming comfortable with its slow-speed characteristics and finding where/how it stalls.
Old 03-19-2010, 10:16 PM
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Default RE: Flaps and slowing this thing down

ORIGINAL: ChuckW


ORIGINAL: mooseflier
I'm curious though now that I have it set up and got the servo extensions I need to seperate them... for flaperons, do you make the aelerons go up or down? In planes that I've flown in (747s and such), the flaps always go down, but someone above mentioned that they should be set to go up.
Flaps generally do go down. They are also generally dedicated surfaces on the inboard portion of the wing. The problem with using the ailerons as flaperons is that it creates wash-in toward the tip of the wing (someone correct me if I am wrong). This could create a situation where the wing tip stalls easily or cancels out any beneficial wash-out that may have been put into the wing intentionally.

What Ed Moorman was referring to is using the ailerons as spoilers by deflecting both upward. He can elaborate on them much better than I can and explain why they are sometimes used and how they work. I've personally never tried them but I might one of these days.

Doing flaperons/spoilerons should just be a mix in your radio. You need to used dedicated channels for each aileron servo rather than a Y-harness then just program the function. Your DX-7 manual should explain it.
Chuck, Spoilerons are fun!! Ed and I were talking set up after one of his articles in RCR and I went ahead and did it but I used them on my Extra 300 CG kit plane, they are a lot more fun on my Hots but I went back to flaperons for playing in the wind. Moose, I used to fly a lot of the super sportsters and the trick to slowing them is just flaring them a couple of times during your approach until you get to the speed you want. As you fly the plane more you will notice you don't even need to do that. Just give it a little time and you will be wondering why you even thought about adding flaps.
Old 03-19-2010, 10:51 PM
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mooseflier
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Default RE: Flaps and slowing this thing down

Sounds good, thanks again for the advice!
Old 03-19-2010, 11:09 PM
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mooseflier
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Default RE: Flaps and slowing this thing down

Well I'm currently glueing in about 4 or 5 MORE ounces in the front of this thing, on top of about 5 that I already had under the engine. Used up just about every fishing weight I have. Drove around and couldn' t find any tackle stores open after 7pm on a friday. And tire stores don't seem to use lead anymore. Anyone know of a good place to find lead if you're in a bind on an evening, just out of curiousity? I'm really surprised that how tail heavy this plane ended up being. I'm also used to balancing all my other planes with the tank full, and I even use to add weight to make them tail heavy. This could odd when I go to fly tomorrow. Suppose to be a nice day too!
Old 03-20-2010, 01:50 AM
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Default RE: Flaps and slowing this thing down

Hi mooseflier

Regarding finding lead, here are some ideas. Shooting ranges are great! If it has a sandbank behind the target area, you will find tonnes of lead there. I have on a couple of occasions gone to the shooting club and asked if I could sift the sand. So far nobody ever had any objection. You walk away with more lead than you could use. The shooting club ends up with a nicely "re-shaped" sandbank. Smiles all around.

Crack open a few discarded car batteries. Heaps of the stuff in there. Just be carefull about the acid. Best idea is to fill any old battery with water and rinse it a couple of times, untill all the acid is removed. Break out the grids on the inside=heaps of lead.

Gun stores are another great source. (Unfortunately not free)
Old 03-21-2010, 03:03 PM
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Default RE: Flaps and slowing this thing down


"...mounted two mini servos just in front of the stabalizer's leading edge in the firewall, one for each elevator half. I've always hated split elevators with a four-channel radio, so I put some servos in the tail to make the elevator rock solid."

Is the rudder servo in the tail also?

You need to put the servos in the fuselage where they belong and link the elevator halves as it was designed.
If done properly you won't have any slop. You should not have to add any weights at all to get it to balance.
Just move the battery location. Also as mentioned previously you should balance with an empty tank.
The plane is designed with the servos sitting near the CG normally, remember how leverage works, the CG is about 2/3 to 3/4
the length of the fuse, usually where the wing spar is, any weight in the tail has a 2x to 3x leverage over the nose end.
And I think you mentioned you where using 2-stroke so the engine is light. There is no way you can afford the weight
of a servo in the tail. You will be amazed at how well this thing will fly when you get the balance right, it will flair nicely
and set down so gracefully and much slower than you are used to. BTW, flaps are a blast too but got to be well balanced first.

Enjoy.

Old 03-24-2010, 10:10 PM
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Default RE: Flaps and slowing this thing down

Check out one of your local tire stores. they're not supposed to reuse lead tire wieghts and they wind up scrapping them. If one store turns you down ongiving you the weights, try another. I hit 2 stores; first said they can't give them away because lead is a hazardous waste, second store offered me four 5gal buckets full of discarded weights...I took about a shoebox full. Melt them with a blowtorch while holding them by the steel tang with a a pair of pliers.
cut up and folded softdrink cans make excellent molds for molten lead as well.
Old 03-25-2010, 02:46 PM
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Default RE: Flaps and slowing this thing down

Your plane is too heavy and it is also too nose heavy. The .46 is too heavy for that plane and in order to compensate for the nose heavy condition you may have had to add tail weight to balance it. In order to get those super slow, nose high landings you need a light plane that is more tail heavy than nose heavy. By tail heavy I am talking about sneaking the CG back a little at a time until it lands the way you want it to.

I've seen that plane fly fantastic on a good .40. There is quite a bit of weight difference between the two engine sizes. Most people now like to overpower their planes to be able to perform fantastic 3d and vertical manuevers. I prefer a light, well balanced plane that flies more on the wing than the prop. Wild aerobatics are fun and easy with proper balance. The other benefit is those nice slow landings.

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