Help! Adding flaps to Tutor

[codygoodman1337]

Does anyone have a video or webpage link for a tutorial on adding flaps to the FT Tutor? I've seen a few people who have done it, but can't find a tutorial. I've thought of cutting 2 strips of foam and making a tape hinge under the trailing edge and adding servos to drop them, but I've also seen some where there is just a flap cut in the trailing edge of the wing. Pros and cons? Advice?

 

[SSgt Duramax]

Depends on what you want.

You could do split flaps (adding a slat to the bottom of the wing) normal flaps where you cut it out in the wing, or extend the ailerons and do flaperons.

If you do separate flaps, you will either have to reverse a servo, or mount them going the same direction, or work some kind of mix out in your radio.

Split flaps on my FT P40 wing. Note my servo mounting.

 

[codygoodman1337]

Depends on what you want.

You could do split flaps (adding a slat to the bottom of the wing) normal flaps where you cut it out in the wing, or extend the ailerons and do flaperons.

If you do separate flaps, you will either have to reverse a servo, or mount them going the same direction, or work some kind of mix out in your radio.

Split flaps on my FT P40 wing. Note my servo mounting.

View attachment 223003

This is pretty much what I'm thinking. Did you just use tape to attach them? Like a fiberglass strapping tape? Also any input on how wide they should be on a tutor wing? Don't want them to cause too much drag.

 

[SSgt Duramax]

This is pretty much what I'm thinking. Did you just use tape to attach them? Like a fiberglass strapping tape? Also any input on how wide they should be on a tutor wing? Don't want them to cause too much drag.

They shouldn't cause drag when retracted.

I just cut the length of foam I wanted (mine extend from the fuselage to the aileron) and i de foamed about a half inch just leaving the paper on one side and glued it on. Tape would work fine though. I would just do the same, and run them from the aileron to the fuselage.

This is my flap before cutting it out all the way. I guess I had about a 9x3 piece of foam, I cut a half an inch off just leaving the bottom paper. Held it up to the wing, and traced the wing down on it.

 

[codygoodman1337]

They shouldn't cause drag when retracted.

I just cut the length of foam I wanted (mine extend from the fuselage to the aileron) and i de foamed about a half inch just leaving the paper on one side and glued it on. Tape would work fine though. I would just do the same, and run them from the aileron to the fuselage.

This is my flap before cutting it out all the way. I guess I had about a 9x3 piece of foam, I cut a half an inch off just leaving the bottom paper. Held it up to the wing, and traced the wing down on it.

View attachment 223009

Awesome! I got the checkered pattern vinyl in the kit and I've been itching to use it on something. I think I found my project for the night.

 

[SSgt Duramax]

Awesome! I got the checkered pattern vinyl in the kit and I've been itching to use it on something. I think I found my project for the night.

The advantage of adding split flaps for you would be that you dont have to permanently alter the wing. If you dont like them or they break, either pull them off or tape them shut.

 

[codygoodman1337]

The advantage of adding split flaps for you would be that you dont have to permanently alter the wing. If you dont like them or they break, either pull them off or tape them shut.

Another good point

 

[Piotrsko]

Split flaps are a drag generation device, they don't add much to lift. If you want to slow down or increase the rate of descent they are perfect. If you're looking to add extra lift for slow speed flight, do something else. The good SSGT doesn't say how he uses them, but I suspect he likes the wounded duck descent rate when deployed

 

[SSgt Duramax]

Split flaps are a drag generation device, they don't add much to lift. If you want to slow down or increase the rate of descent they are perfect. If you're looking to add extra lift for slow speed flight, do something else. The good SSGT doesn't say how he uses them, but I suspect he likes the wounded duck descent rate when deployed

They do add some lift. Not as much as hinged flaps. You're making them sound like spoilers here. At the very least, if he doesn't like what they do, he can take them off, cut little slices and a hinge in his wing, and use the exact same electronic set up and placement (and probably even control rods) to get hinged flaps. All he is out is a couple strips of foam.

Although, since you mentioned it, I do fly in a smaller area, and I don't like setting up long, wide, low approaches, so you are partially right, I use them to double as airbrakes. I tend to bring my plane in about 75 feet up, and drop down pretty quick pulling a 180 while decending, then jam the flaps once it straightens out for final, at which point it scrubs considerable speed about 10 feet off the ground and drops gracefully on to the wheels. Although I don't really need them at all, much like his plane. If I don't use them, it just rolls further when contacts the ground a little harder.

 

[Piotrsko]

Ahh what we used to call military approach to land. Thought so. I think you are associating the pitch change and up trim requirement as a lift increase as opposed to a camber change, but carry on.

 

[quorneng]

Now if you really want to slow down the stalling speed and increase the drag.

Both flap sections are moved by a single servo on each side.

 

[SSgt Duramax]

There are some cool ideas for fowler flaps on thingiverse too. Someone on here made some pretty cool slotted flaps using popsicle sticks as hinges too. Well they were kind of a slotted/fowler combo type thing but they worked.

 

[Pieliker96]

There are some cool ideas for fowler flaps on thingiverse too. Someone on here made some pretty cool slotted flaps using popsicle sticks as hinges too. Well they were kind of a slotted/fowler combo type thing but they worked.

Not technically proper fowlers since they're simply hinged don't translate aft

I'd hesitate to say "they worked" since I haven't done much with them yet, but from the few seconds of flight time I've had with them down - massive change in deck angle, to where I could point around 10 degrees nose-down and still maintain level flight. They probably create tons of drag and a good bit of lift, especially being externally blown.

Easiest solution is to just extend the aileron hingeline up around where it meets the fuselage. Keeps the upper surface looking nice as well.



I used this technique on my FT Otter, here shown at half-deflection. They work decently well: a bit of extra lift and drag to help you during takeoff and landing.

 

[quorneng]

A slotted flap works using the Coanda effect where a stream of higher pressure air 'sticks' to surface around quite a sharp radius.
Model planes have relatively very low wing loadings so how much air and at what speed passes through a relatively narrow 'slot' is open to question.
Indeed part of the reason why models can achieve angles of attack well beyond that of full size without stalling is down to the relative viscosity of the air at model sizes. It tends to stick to a surface anyway.

Well that's my take on what is happening with low speed aerodynamics.

 

[FishbonesAir]

Now if you really want to slow down the stalling speed and increase the drag.

Both flap sections are moved by a single servo on each side.

Really should have used some nice hinges too, and created a slot at that point!

 

[quorneng]

Fishbones
Models have a low wing loading coupled with the relative viscosity of air is the reason that "slots" are not effective unless the gap is way over scale. Even then the benefit of the slot in delaying flow separation is nothing like that achieved at full size.

In my experience a simple flap on a model, even a two section one, works very well. It is relatively simple to do and even more important it is light.