Champstarr

Hi everyone,

currently I am building a glow powered VQ Yak-9 (58.9 inch wing span) with a .70 four stroke. Many of the flight reviews I have read for this model explain that the plane has an usually high approach speed and is difficult to slow down.

This model does not have flaps but would it be feasible to add them? Is it risky to install custom add flaps to models that don't have them included from the factory?

Any input is appreciated.

Thanks.

AA5BY

I'd not mess with them on that size model. First, is the additional weight. Second, your use of a 4 stroke will be as beneficial... use a larger lower pitch prop. Four strokes generally idle down well, and with a large shallow pitch prop, it will provide a lot of braking and good takeoff and climbing torque.

RBACONS

My Feedback: (3)

Rather than flaps, you can implement spoilerons (tilting both ailerons up slightly) for landing. No extra weight, induces drag to help slow the plane, and washes out the wing to help reduce tip stalling.

jetmech05

Flaps are not speed brakes, they are lift augmentation devices. Deploy flaps with too much airspeed and the airplane will balloon up on you.
several things can cause too much speed on landing/approach. Too much altitude the trade off for too much altitude is airspeed as you dive the strip, too high an idle, too small a prop, CG too far forward.
I would leave the flaps alone I think

Champstarr

Wow! Great stuff, thanks for all of the insightful feedback.

bikerbc

When you deploy flaps your airplane will pitch up but to prevent this you mix in some down elevator . Flaps are great for slowing your aircraft .

bikerbc

On full size aircraft flaps are used for landing and taking off . They increase lift and drag so at the same time that they increase the lift of the wing they allow you to slow down . When first deployed your aircraft will often pitch up depending on your speed . So to prevent this down elevator is mixed in with your flaps . Even on full sized aircraft when flaps are deployed you trim in down elevator. You need to set this by trial and error. It dosen't take a lot . One other thing I like to do is slow my flap servo down .Not all radios can do this . It makes the pitching up a lot easier to manage untill you get the mix set properly .Flaps are great for slowing your aircraft for landing and if it looks like you can add them I would not hesitate . If you have them and don't like them you don't need to use them . I think however once you get used to them you will be very happy to have them .

Gray Beard

My Feedback: (-1)

I'm more of a bigger prop with a smaller pitch person. It just depends on the plane and I do a lot of testing. For fun I was using a three blade with a low pitch on my Kaos. It was like using an air brake when I cut the power. Flaps?? Probably not needed or the plane would have come with them.

Champstarr

Thanks for the feedback fellas

jaka

Hi!
Use a 13x6 or 14x4 APC, RAM or Graupner G-Sonic prop. Those are the best prop brands available.
Flas are no good on a small plane like yours!