232CAP

I just got a older yellow f4 never flown. it was built with scale ailerons and no flaps. should i set them up as flaperons for take off and landings? it has an 0s 91 with a dynamax fan. not many ducted fan fliers around my area. thanks

tamjets

My Feedback: (2)

You don't needed.
I flew my both df and turbine without flaps.
Tam

joeflyer

My Feedback: (48)

Mine is built the same way and I use 15 deg. of flaperon for take off only. The Yellow F-4 has its main gear in the scale location, which is quite far behind the CG. This makes the plane difficult to rotate. If you read the Yellow instructions they recommend 15 deg. flaps for take off and warn you not to use them for landing.

If you have plenty of runway and can get up lots of ground speed you don't need them. My field has a 400 ft. paved runway and I use most of it for take off. If I rotate a little too soon the plane all of a sudden leaps off the runway and you immediately have to give it down elevator to get the nose down and build up some speed or it will stall. I have seen a couple crash this way.

The best (safest) way to take off is to get up plenty of ground speed and gently fly it off the runway. 15 deg. of flaperon greatly helps the tendency to over-rotate, and you can fly off the deck at a slower speed. Yellow claims that when coming in nose high for a landing that flaps can blank out the elevators making them ineffective, so I have never tried landing with any flaperon, and you really don't need it. On a cool day I can take off fine without flaperon, but definitely need them on a hot day.

A couple other tips for take off are to make sure you have some nose up attitude (or it won't get off the ground), make sure it rolls easily, make sure your engine is peaked out, and do a couple of taxi runs to make sure it will get up to flying speed okay. The elevator is a little mushy when it first takes off. Build up some speed before entering your first turn. Once it gets on the step it's quite fast. The plane takes a little getting use to, so slow it down a little until you get a feel for it. Keep some power on and nose up when coming in for a landing. I don't recommend trying to fly it from a grass field.

Good Luck,
Joe

232CAP

thanks Joe for the info, i don't have the building instructions for the jet. What throws do you use on your f4? thanks

joeflyer

My Feedback: (48)

Cap,
Here's what the manual says, and how I have mine set :

Manual_ my Hi_ my Low
Ailerons (+/-): 1/2"_ 1"_ 3/4" measured on inboard side
Elevator (+/-): 1 1/8"_ 1 1/2"_ 1 1/8" LE at fuse
Rudder (+/-): 1 1/2"_ 1 1/2"_ 1 1/8" at bottom
Flaperons: - 15 deg._ -1/2" for Take Off
CG: 8 - 8 1/4"_ 8 1/4" behind LE of wing at fuse
Elev. Neutral: 1/4"_ 1/8" above the fuse panel line that angles down at LE

I believe there is a misprint in the manual +/- 1/2" isn't nearly enough aileron. Even 1" does not give a real crisp roll rate. I use exponential and normally fly on hi rates all the time. Try my hi/lows for your first flight. You can try both rates to see what you like and adjust from there to suit your flying style.
m
Good luck,
Joe

VIRUS

Hi, I have mine set up pretty much as joeflyer has his...I use flaperons, about 15 deg. for take off...every take off. i had a crash on about the 5th flight of this plane...pitched straight up, came down on the right wing....right wing turned to powder....i was lucky, nothing else was damaged. anyways, built another wing from yellow, used flaperons ever since...problem gone.
i also use flaperon for landing, between 15 and 25 deg., depending on the wind...on strong gusty days i never use them for landing 'cause you have less aileron effectiveness with the flaperons down, so it's easier to keep the wings level on final. i've never had them blank out the stabalisers either. mine has the stab mixed with flap....18% up stab with flap extension to counter the pitch down tendency with flaperon extension. and i know they say never do this, but i have mine balanced at 8 2/3" behind the leading edge at the root with the tanks full...flies much better now. the plane really is pretty fast once it gets on the step...downwind low passes are just sweeeeeeeeeeeeeeeeeeeeeet!!! and she sure looks pretty coming in nose high on approach and landing
hope this helps, and enjoy your f-4!!!
lee.

Bob_B

My Feedback: (11)

I want to clarify that by Flaperons you mean mixed to the elevator but movement in the opposite direction. As opposed to pure flaps moving to a fixed down position.
Thanks, Bob

joeflyer

My Feedback: (48)

Nope. Flaperons combine the function of flaps and ailerons. When we say that we are using 15 deg. flaperon that means the neutral position of the ailerons is dropped 15 degrees below the trailing edge of the wings. This provides extra lift, otherwise they function like ailerons. I control the neutral position with the flap switch, lowered for takeoffs and normal for regular flying.

Joe

FireBee

My Feedback: (34)

232CAP, Follow joe's advise. Mine set up about the same and flys great. mine has os.77/Danamax combo at 10 lbs.
I've seen same F-4 w os.91/dynamax and 14 lbs and it flies exactly the same. Like a fast pattern plane on rails.

Landing Gouge: Three words : let it settle.
I learned to land from him and this is so easy now. Use Navy oval approach pattern for landings not rectangle.
start w/ upwind gear check pass at 1/2 throttle, turn to downwind and continue to bleed off speed. Pull throttle to 1/3 and start 180 descending turn to final. Control descent w/ throttle as required but around 1/3. As plane makes the runway, roll to wings level (i'm about 20 ft here) for lineup. Here is the key: begin to lift the nose and it will find a particular nose high groove it likes and then just "let it settle" in for landing. About 20mph. Check descent rate w throttle. About 1 ft off the deck bump up the engine slightly to reduce the sink rate at touch down on mains for perfect landing. (Later you can do a break upwind and drop gear on the downwind).

I also have flaperons but have yet to need them on takeoff or landing. I raised nosewheel 1/4 inch to help rotation on takeoff.
At full speed (estimate 150mph) I notice a "slight" porpousing in pitch. something like a +/- 2 inch bobble in the nose. Back of slightly and she is on rails. Also if you fly too far away the wings tend to disapear when you turn in to you again. Spins are no problem and crosswinds are easy with that wide track gear.

I balanced mine w/ trapeeze method but any will work. balance w/ fuel and gear up at most aft cg on plans. I have since added 1/4 oz to elevator access area as it helped the inverted flight with less down stick required.

Best looking and flying jet out there. Love that 'Toom.

Happy landings,
Mike

Bob_B

My Feedback: (11)

Okay, I appreciate the clarification. Have you ever given thought making the Aileron longer than what they call for? I'm very excited about getting started on mine. What torque range servos do you recommend for the elevator function? Also what wheels do you use on the main gear and are you using a double nose wheel and if so whose strut?

Bob_B

My Feedback: (11)

So would lengthening the ailerons be a good idea? I know it would not be scale but if it fly better with less throw(drag) it might be a good idea?


I believe there is a misprint in the manual +/- 1/2" isn't nearly enough aileron. Even 1" does not give a real crisp roll rate. Good luck,
Joe
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joeflyer

My Feedback: (48)

If I remember correctly the instructions give three options for building the wings: 1) ailerons only, 2) ailerons & flaps, and 3) flaperons. The flaperon option is basically the scale aileron and flap as one long piece. I don't think that would make it fly any better. The larger surface would just require less throw to get the same roll rate. Scale ailerons work fine for me. Perhaps there is someone out there who has tried the flaperons.

You need a strong servo for the elevator, 90 in-oz. or better. I have a Hitec 645 with 6.0 volts on mine. Also I highly recommend the optional aluminum heavy duty elevator arms that Yellow sells. The plastic ones that come standard have been known to break easily.

My main wheels are 2.5 " Sullivan Skylites. I like them for my jets because they are solid tires. For the nose wheel I have two Dubro 1.5" tailwheels. These have a hard rubber tire and a solid aluminum hub. My strut is a Robart straight one. Yellow also sells a nice nose strut that is more scale.

Bob_B

My Feedback: (11)

Thanks for the info Joe.

joeflyer

My Feedback: (48)

Correction on the elevator servo. I have a Hitec 615MG. It puts out 132 in-oz. with 6.0 volts.

Joe