Topic: Whisper 2 Servo to 4 Servo Wing Converversion

I have a 2 metre Whisper with a 2 servo wing. The model flies well but does not get used as much as my other models as it can be difficult to to land at times. I am thinking of converting it to a 4 servo wing. Has anyone done this before?

Looking at the wing with a strong light behind the wing you can see the inner structure wing of the wing. There does not seem anything in the way. I was planning to cut out the flaps with a razor saw and then bottom hinge the flaps. I would make cut outs for the two extra servos and fit some covers. I may have to insert a drag spar to strengthen up the wing. I would use microballons and west epoxy to close off the open faces of the flaps.
 This sounds very drastic. The alternative is sell on the model and put the money towards a 4 servo replacement moldie.

Hi Bartplus4
I've modded other moulded 2 servo wings to 4 and they all looked like a bodge job 
IMO go for a 2nd hand pair of 4 servo wings 
There is a chap on BMFA classifieds at present selling a Blade with 2 sets of 4 servo wings - might be worth a call and an ask? - nothing ventured........
Good luck
Pete

the whisper isn't bottom hinged anyway
razor cut the ailerons half way out, fill in the ends of the surface with a little 16th balsa
cut the bottom of the wing to allow the servo to sit in, connect up same as the ailerons but with the horns facing rearwards a little for more movement back ( down ).
you may need to trim some of the now flap bottom skin away to allow more movement.
it'll be as good as the proper 4 servo version

The existing ailerons do not run the full length of the wing. They are only half span. I propose to keep them as they are. The new flaps would be cut into an existing static section of the wing.
Looking at photos of the 4 servo version the wing looks identical to the 2 servo version only differing in that the inboard section has been cut out for flaps.
I would end up with flaps and ailerons of equal length. The flaps would stop about 30mm from the fuselage.

sorry, thought they were already full span.
i'd still be tempted to top hinge tho, just because they don't have wipers, unless you intend to make some?

I would just dial in a load of down aileron (Flaperons) and elevator comp and not bother with crows

UP aileron UP!

UP aileron UP!

Horses for what ever
as long as it slows it up
Im sure the is some science between spoilerons and flaperons but I would always chose the latter and have found that even planes they say use spoilerons still work better the flaperons
just suck it and see, to hell with equations

it's not equations, yes they both cause drag, but down causes the tips to stall earlier meaning your stall speed probably increases
up allows you to hang on the elevator which is actually what slows the glider without stalling

I have tried the Spoileron route and it does help to slow the plane down and bring her in on a steeper glide path. However they do not work as well as crow on my other planes. This limits the places I can fly the plane and also the wind speeds. As a result it does not get used as much as my other planes.
Thanks for the advice.

I think what you describe will work. It might depend on how strong the skin you are hinging off is (it is an xmodel....).  I don't know how flexible the skin is, but as you say you could install a drag spar to stiffen things up a bit.

Seems a lot of work though. And potential for disaster if you make a mistake. 

I thought a Whisper was a light air craft but I guess it would fly in most conditions 

The Whisper uses a MH32 section and is fairly light. I have mixed in a little of droop on the ailerons for a thermal setting (about 3mm). It goes well in light air. It also has provision for ballast in the wing for windier days.

At the main site where I fly there is ample room to land away from the lift zone. However on other sites I have to land in the lift zone slopeside or in a very tight area bounded by walls and fences. I do not attempt to fly there with the Whisper. I prefer to fly one of my four servo planes or something foam based.
The purpose of the 2 to 4 servo conversion is to extend my use of the plane.
On reflection perhaps the conversion is too ambitious and prone to error.

Hello,
        If its any help i have just done the same thing but to a composite jet,i cut away the bottom and simply used some silicone to strengthen up the hinge line.
cheers Euan.

I was thinking of a balsa drag spar in the wing set back slightly. I would use some balsa and epoxy microballons to close off the open flap surfaces. I was considering making up a radiused molded wiper to glue onto the flaps.

copy the ailerons, top hinge, no wiper, lots of whistles!!
I had mine out in 60mph winds before, 16oz onboard, it loved it!!

At the main site where I fly there is ample room to land away from the lift zone. However on other sites I have to land in the lift zone slopeside or in a very tight area bounded by walls and fences.

If you have tougher 4-servo planes available, then I wouldn't bother.

Unless you either

• Fancy the build experience
• Like the landing challenge

In which case, go for it!