Hello flying friends!

I got my hands on a Super Stearman from Kyosho. I like this plane a lot but i think the wing incidences is not correct. Also the CG point is described in my manual 15-20 mm from leading edge on the lower wing but on Kyoshos homepage they write 4' , i assume this is the upper wing. To get it flying straight i must have nearly 5 mm of downtrim on the elevator. Does anyone have any experiences with this model?

Best
Thomas

I don't have the Super Stearman, I have the PT17 Stearman and the balance point is listed at 15-20 mm from leading edge of bottom wing also. Thats where I balanced mine. I balanced it inverted between the 15 and 20 mm marks. It did take a few clicks of down trim to get level flight (not 5mm worth of down), but it flies great and flies inverted with very little down elevator applied. I would say it is probably at the aft edge of the cg range. It tracks straight and level and doesn't appear to fly like it is tail heavy. I would say the 4" on Kyosho's web site would be if you are balancing from the top wing. I didn't have to add any lead to balance with a Saito 56 in the nose. Hope this helps.fossil

Greetings.
My Kyosho Super Stearman is currently in its fifth year of flying, and I yet have to tire of it.
I looked in my records and found the balance point at which to place the fulcrum, is four inches aft from the leading edge under the top wing (101.6 mm). Balancing required five ounces of lead to be added to the front of my engine mount beams. Power is a TT .46 with a Bisson Pitts style muffler, SonicTronics 310 glow plug, swinging a MA 11 x 6 prop while using Morgan Omega 5% fuel. Throws are set to: Aileron--5/8" down, 11/16" up, Elevator--5/8" up, 7/8" down, Rudder--1 1/4 " both left and right. The aileron hinge line is sealed with Monokote. Only one important change was made to this model: A wedge-shaped piece of spruce was added to the landing gear strut mounting face at the fuselage to angle the gear forward so that the centerline of the wheels are even with the leading edge of the top wing when the model is horizontal (level flight attitude). This prevents the model from nosing-over. New screw holes were needed, of course, and the old holes plugged.

Good luck with your endeavors.
Regards,
DrGO

http://www2.towerhobbies.com/cgi-bin...?&I=LXS634&P=7

My Kyosho Super Stearman is now 3 years old. It is powerd by a Thunder Tiger 54, 4 stroke turning a 12 x 6 prop.

I found that the control throws as supplied by Kyosho were on the extreme side for me and toned them down. 1/2 the recommended elevator throw was all I programmed in and it flies nicely. Loops well and will snap and spin all I want.

The model needed about 30 grams of weight up the nose end. I balanced it slightly nose heavy on the factory c of g point.

It depends upon your choice of engine as to how much, if any, weight will be needed.

The upper wing incidence is pretty well correct as built. The upper wings of bipes should be 1 or so degrees negative anyway. Mine did have a tendancy to climb when inverted, (without any down elevator input) so I added a small, thin washer under the front of each cabane strut mount between the strut mount and the wing, to reduce the incidence by .5 or so of a degree. This put a stop to the climbing and it flies straight and level on 1/2 power, with no elevator input regardless of whether it is right way up or inverted.

I found mine also needs to have the nose forced down when approaching to land, otherwise it is quite content to fly on straight and level, even with power off, until it looses way and just stalls and drops. (ouch)

One caution. The u/c dural is soft and will twist if the landing is on the hard side.

The only changes I have to the kit during assembly were:

I mounted the u/carriage with 3 counter sunk 5mm nylon bolts rather than with the supplied self tappers.

I also used Dubro axles to mount the wheels on rather than the machine bolts supplied to use as axles.

I fly off a grass strip, somewhat rough, so did not use the wheel spats.

I discarded the machine nuts/bolts/self tappers supplied to
attach the cabane struts to the wing and fuselage. I drilled, tapped and c.a. hardened each hole in the wings and fuselage to 2 mm and used 2 mm nylon bolts to attach the supports (nylon will not vibrate loose) and then used allen head bolts and nylon lock nuts to attach the cabane struts to the metal mounts.

I routed the battery pack /switch harness connection through the cockpit so the battery can be disconnected when the model is stored, and also the model can be transported, WITHOUT having to remove the wings. (Saves huge amount of time at the flying field not having to do up and undo all those fiddly nuts and bolts, especially at the end of the day when the light is fading.)

I fitted a control horn to EACH elevator half and made the elevator pushrod a "Y" rod (split elevator)

All in all, it is a great airplane to fly. I love flying mine.

Thanks all for your replies!

But one more question, how much thrust should the engine have?

Keep flying!

Sorry, saw it on http://www2.towerhobbies.com/cgi-bin...?&I=LXS634&P=7

It depends upon yor engine choice. This is one model that can be over engined. Screaming .48 - 51, 2 strokes etc, are probably over the top and COULD lead to left hand yaw tendancy's. Extremely powerful engines will not give any additional speed.

It has a relatively light wing loading, so will fly itself off the ground when the speed is right. The fat fuselage, cabane struts etc, equal lotsa drag, so it also comes down quick if the power is off.

If you want to do huge pattern like loops, go buy an Ultimate. This is not the plane for you.

I didn't add any additional thrust from my 4 .54 stroke installation. Just installed the engine as per the instructions. It suits the model well and makes it a pleasant model to fly. It cruises along nicely at 1/2 throttle. Any 4. stroke in the .50 class would suit.

If you want to 2 stroke it, try something like a Thunder Tiger GP.42 or a Magnum XL .46.

Hi Woody 51!

I'm happy with the machine dont misunderstand me. On the http://www2.towerhobbies.com/cgi-bin...?&I=LXS634&P=7 page the engine they recommend is what you are also mention. So that is little confusing because Kyosho says 0' thrust. The plane flies very well, i like it a lot but it want to climb and needs downtrim. I checked the incidences and the upper wing has 0 at the root, -0.5 at the tip, the lower wing has +0.5 at the root and the same at the tip. You write in you reply..

The upper wing incidence is pretty well correct as built. The upper wings of bipes should be 1 or so degrees negative anyway. Mine did have a tendancy to climb when inverted, (without any down elevator input) so I added a small, thin washer under the front of each cabane strut mount between the strut mount and the wing, to reduce the incidence by .5 or so of a degree. This put a stop to the climbing and it flies straight and level on 1/2 power, with no elevator input regardless of whether it is right way up or inverted.

Was it really in the front you put the washer? I thought i had to put the washer on the back of the struts to lift the rear of the wing to add more negative incidence.

Best regards!

Hi Slotts,

My climbing problems came when my model was inverted. It climbed when inverted and I did not like this. I had to feed in a lot of down elevator.

When rolling back to right way up, this could present problems if one didn't take it off quickly enough. (Too close to the ground = "SPLOT!")

When inverted, the negative incidence changes to positive. (Wing TE is lower than the LE, giving the same effect as lowered wing flaps on a control line model, viz - climb.)

I first inserted a 0.5mm washer under each of the front cabane struts, (between the wing and the cabane strut anchor point) to make the incidence more neutral (less positive when inverted and more positive when right way up, remember it is negative as built as per plan.) but felt this was a little too drastic when I next flew the model.

So I tried a thinner one. about .03 mm, (when measured on a vernier scale.) and was happy with the result. (There is still a little negative incidence, just not as much as Kyosho designed into it.)

If you want more negative incidence, (when right way up) insert it under the rear strut.

Less negative incidence will result in more climb, when right way up (and less when inverted,) especially when under full throttle or flying into a strong headwind.

After mucking about with the incidence, I trimmed the model with a couple of clicks of down elevator, to fly "hands off" at 1/2 throttle. (right way up)

It 's a matter of juggling the washer thickness until you get the result you are happy with.

Mine will still climb under max throttle, when flying right way up, However it now does not climb when inverted.

I can now fly it inverted with no down elevator input on the Tx, which is what I set out to achieve in the 1st place.

Yours sounds as if it needs to have a slight increase in the NEGATIVE incidence on the top wing, or bottom wing set to 0 degrees. You could go either way. My models bottom wing is 0 degrees. If you chose the top wing, (probably easier) then try a VERY thin washer under the rear mounting point. Go easy, a little at a time.

Oh, one other thing, check your Horizontal Stab incidence as well. I once had a Cessna C34 ARF which needed a heap of "UP" trim to stay aloft. The problem was negative incidence on the horizontal stab, despite it being built as per what came straight out of the box. (The factory had made a mistake when cutting the original balsa bits pre construction.)

Once this was cut out and reglued with correct incidence (0 degrees ) all became well.

As for the side thrust what I meant was don't add any extra if your using a 50 size 4 stroke. or low powered .46 2 stroke. Go with Kyosho's settings, they're fine.

If anyone is thinking of using something in the .50 size 2 stroke genre, such as a Super Tigre G51 or OS 50 SX, then additional side thrust may have to be considered.

This model cries out for a 4 stroke, that's why I bought one for mine. Mine is installed sideways as per Kyosho's instructions.

As for the C of G, I started with the instruction settings, but then added weight to the nose, it was tail heavy initially but even at neutral on their settings, was a bit of a pig to fly intially. ("Brown Jocks" material.)

I ended up (trial and error) with it balancing neutral 4 centimeters (40mm) from the BOTTOM wing LE, measured when the model is inverted.

This is about the border of where the red LE trim meets the white wing covering. I am comfortable with this and it is a nice model to fly.

I also toned down the elevator settings by almost 1/2 of what Kyosho give in the instructions. Even with the C of G moved back, they were still too drastic for my liking.

Have fun.