red_guy

anyone tried it? how dit it go?


last week I modified my qhor so I could use the flaperon mix on my radio. today I flew it and when I landed and lowered the flaps it just dove into ground. I was coming with a little power like I always do, so I totaled the plane. the wing is reusable but the fuse just broke begind the engine mount. I use a aluminum engine mount (cut from a 1/2" thick aluminum plate) and managed to bent it pretty bad.

can anyone explain me what happened. to my knowledge the flaps are supposed to slow the plane while mentaining the lift. but in this case I lost the lift and the plane dodged into ground. very messy

regards
red guy

DLSmith2

Red guy,

Sorry to hear about your crash. I think a couple of things happened to cause it. First, when you lower flaps on a full scale plane, it will be like putting brakes on, causing lots of drag. When that happens the nose wants to pitch down, altering the angle of attack of the wing and making your glide slope go from 3* to 5* or 10* depending on the aircraft and size of the flap. You can control that with throttle and elevator management. Second, when you put flaps on a regular aircraft wing, they cover maybe the inner half of each wing with the ailerons extenting to the wing tips. A friend put separate flaps on his Deb (cut part of the aileron to make it a flap), and when he deployed them the first time, the pitch down was dramatic. His flaps were about the size of a Qhor aileron, so with that relatively small sized flap for that big of a wing it caused quite a startling amount of drag. Once he learned to anticipate it and control it better, he made some really short, slow approaches.

When you put the flaps down on a Qhor, I'm assuming that the flaperon moved the entire aileron down, it alters the airflow and since they are wide to begin with it alters the airflow drastically. Not to mention with all that surface area sticking down, you may have masked the airflow to the elevator, effectively losing all pitch control to counter the new nose down attitude.

Don't give up on the flap thing, just practice it at least two mistakes high, and with VERY LITTLE increments to start with. For that size airplane, with about 2" wide aileron you might only need to drop it 1/4 inch to get the desired effect. Then when you master it you can increase the throw to 1/2" or more and use the 5* - 10* glide slope to your advantage and make some amazingly short slow landing approaches.

Good luck, and let us know how it goes!

Blue skies,
DL

red_guy

thanx DLSmith2. The same told me the guys at the airfield but wanted to ask on the coro forum cause these planes fly a little bit different. Well, I put about 1" of flaps. A friend of mine told me to do so cause he does it like this on his SkyMax (aerobatic trainer). But now when I think of it he has barn-door ailerons which don't interrupt the airflow to the elevator. And yes, I had no pitch controll. It just dove into ground. And the flaperon switch on my Flash 5 radio is on the right side of the transmitter and I couldn't flip the switch back cause I was trying to gain controll of the plane.

Anyway, I'm done with flaps. On a 1 mile long airstrip this little plane makes so nice long landings I don't know why I needed flaps in the first place. I guess I wanted to try

red

Deadeye

red guy, Coroplast planes don't fly any 'different' than the balsa or foam planes. Some guys just build them heavier than they need to.

I have flaperon on every dual wing servo plane I have, and deploying them on either balsa or coro results in a dramatic pitch down. Since you are using a computer radio, you can also mix in elevator with the flaps/flaperon. This is a necessity, not an option. If you have 0 degrees incidence built into a wing, deploying full flaperon changes that incidence by up to 10 degrees! Don't give up on flaperons, as they are fun to play around with. Just be aware of the inherent changes it does to your airfoil.

red_guy

well, i think i'm gonna dig in my closset for my fms interface and play a little with the simulator. by the way, how a simulated model reacts to flaps? like the real thing??

regards,
red_guy

MrGreenSpeed

Sorry to here You crashed.
flaperons = quick crash device.
Get Your plane fixed and test the flaps/flaperons up high enough so You have time to react.
Every plane reacts differently to flaps or flaperons.
So get 2 mistakes high any time Your testing new stuff.
Good luck.
I'm sure with practice You'll get it right.
Jeff.