A friend of mine purchased a Super Stearman, assembled it, and I test flew it earlier tonight. I took off and it went straight up and tried to do a loop, I had to go to idle and give it full down elevator to stop the climb. I managed to get it down in one piece somehow, then looked it over good. It appears that the wing saddle was cut or ground wrong making the wings pitched way up. The lower wings on all my biplanes are about level to the horizontal stabilizer, but the lower wing on his Super Stearman is way to low in the rear, throwing the top wing off as well, and causing the plane to climb uncontrollably. Not sure what to do at this point, and feel it should be replaced under warrantee... Dennis Flora, Red Bluff, Calif.

No the positive incidence of the lower wing is correct.

You can also see this in the picture Hambone1 posted of his Stearman.


Even if it were a few degrees off, you would only have seen a rapid climb, not a looping tendancy.


It sounds like you had the C.G. way off the mark.

The plane should almost feal nose heavy with the C.G. set properly.

opjose,

You can not see anything on wing incidence from a picture. I believe most bipes lower wings would be set at 0deg and the top wing may be 0deg or -1deg. If you go by what you see in the picture you showed it would indicate that the stab is also positive.

Also if the wings are not correct you would have an uncontrollable flying condition.

I do agree with your comment on CG being off. A tail heavy plane would fly just as freeonthree has indicated.

Actually you can see it on the pics if you look. Pay attention to the trailing fairing on the fuselage.

Check the pictures both on the web site and on Hambone1's post.

The wings have a pronounced positive incidence, that is purposely increased by the fairing at the back.

Mine is the same way and the positive incidence is quite noticable and purposely designed in, w/o causing the aforementioned flight characteristics.

Most of my SMALL Ultimates 40S have at least 1 degree of lower wing incidence as well. The larger ones do not.

Even if the incidence were off to say 3-4 degrees positive, the plane would not pitch up uncontrollably. ( Don't ask ... yes I accidentally flew a bipe this way. )

It would develop more lift and drag and if anything tend to stall out at faster speeds.... he would be inclined to pitch the nose down as it would want to climb fairly fast, but the plane would not go into an almost uncontrollable loop.

All else being correct, you would have to have a fairly pronounced incidence to get into an uncontrollable state... at the least over 4 degrees as I've flown with this much on the lower.

The Stearman has a good tail moment. With a light engine it is fairly easy to get the C.G. too far back.

I have flown tail heavy planes before, but this Stearman is uncontrollable ! I bet the wings are pitched up 10 degree's from the stab ! My new NM Pitts is maybe 2 degree's.
This Stearman doesnt climb, it wants to do backflips !

The bottom line here, is that when a plane fly's thru the air, the wings should be pointed straight forward in relation to the direction the plane is going, not 8 or 10 degree's up from that direction. Here's a good question... how come there is no brand name on the box, or in the manual ? They claim that the normal price for this Stearman is something like $300.00 on the website. Ha ! I have a 4 year old Kyosho Super Stearman, and it was like $250.00. The manual was beautiful in the way they explained every segment of assembly, and they gave the incidence figures as well. The Kyosho came with high quality hardware also. By comparrison, the Stearman that my friend bought, is a POS, and the manual isn't worth the paper it's printed on... The Kyosho devotes a whole page on mounting the engine, Joe's manual has a silly pic and says "mount engine". The manual that came with my Pitts looks like a photocopy, and is much worse than his. Were both very dissappointed, and thats mainly because they tell you that the normal price is like $300.00, making you think that your just getting a good deal. Joe and I have decided to shape his wing saddle to mimic my Kyosho incidence, and that means that the rear of the lower wing needs to come up about 1/2 inch to get there. There is no excuse for this kind of design flaw, especially when they expect you to fly the thing.

Wings straight forward?

No.

My Stearman ( I have the same plane ) has a postive incidence as do many planes that I fly.

It flies very well with a .46 engine.

While I understand that your friend had a problem there is no point in talking about posted prices or the quality of the manual.

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I'd debate that you ARE getting a "good deal" but you have to understand the caveats of this tradeoff, which include the known lousy manuals and spotty tech support.

There are a bunch of people flying these planes at our field, but we do not qualify as novices anymore.

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It sounds as if a mistake was made with the C.G., least Hambone's and my Stearman would have exactly the same problems.

There is no need to bring up the trailing edge 1/2".

As long as the wing sits along the fuselage like any ARF the lower wing incidence should be correct on this plane.

He has a 46 on it... The CG is dead on... Trust me, the wings are pointed up bigtime, not just a few degree's... more like 10 ! My Stearman and Super Skybolt are within 2 degree's of the stab. Even the side view in the manual shows the wings and stab aligned pretty much. If what your saying is true, about his plane, then there's no point in the side view pic at all... I could make my Stearman and Skybolt commit suicide if I added 8 or 10 degree's of positive pitch to the wings also. The plane was not built correctly, and if we just added weight up front to correct this problem, it would have so much drag on it, it still wouldn't fly, and the faster you went, the steeper it would climb. Look at any plane going by at speed, level... the wings are close to level too, no pointed way upward. When we set the wings level by raising the rear of the plane, the fuse is pointed down drastically ! We just don't want anyone to but one of these things without knowing what to look for before they try flying it and crash. You cannot fix incorrect wing incidence with weight, and come out without lots of drag in the air, and this one is way too far off to even concider just adding weight. Lots of things get made wrong ocassionally, somebody put the ting in a jig wrong, or whatever, but these ARF are not inpervious to the same mistakes. I can take a side pic of his Stearman, and I guarantee that you will agree with me. The wings are not even close to reality !

10 degrees is certainly excessive.

You may want to post a pic for NP to review, so that hopefully they will act upon this.

I haven't measured mine with a laser incidence meter, but I'd estimate it to be UNDER 3-4 degrees with the wing seated fully on the saddle.

This one is way over that ! He's flipping the struts now, and were going to meet at the field so I can look at it. Yeah, my Pitts is maybe 2 to 3 degrees +... If flipping the struts doesn't tilt the top wing down alot, I won't try flying it again, thats for sure. All I know is that the wings need to be close to the angle of the fuse, or it's going to go up or down, thats just simple physics. You can put your hand out the car window on the freeway and prove that theory. lol

For Yuks I took my G3.5 model of the Nitroplanes Stearman and set the wing incidences up to see how the plane would react.

With the lower wing incidence at 10 and the top at 0 it still flies just fine but it wants to nose down, and has LOTS of drag.

With the top at 1-2 it still flies ( lower wing left at 10 ).

Now, at 3 degrees, you guessed it, it does EXACTLY what you say.

Even 1/2 of a degree ( or 2.5 at the top wing ) puts it over the edge.



Now all of that said. 10 degrees of incidence on the lower wing looks absolutely wacky.

No one would ever fly a plane that looks so "off".



I still wonder if you actually had a combination of two factors at play. Which makes more sense to me.


1 - The C.G. was too far back or just at the edge of the recommended.

2 - You indeed had a high incidence, but not 10 degrees, say 5 instead. This is more plausible, but still a flaw with the construction of your plane... it shouldn't have been this high.

I would imagine that at 5 degrees or below the plane would not have that "wacky" look to it, and anyone would assume it was safe to fly.


However at this high of an incidence ( let's assume that the fixing posts at the front were too "high" giving you more than the plane should have, due to a manufacturing defect ), the C.G. then becomes absolutely critical. Just a little bit back of the forward most recommended point, and you would have an uncontrollable looping plane.

Just got back from the flying site. I guess my degree jugdement is off because we discovered that he had the cabane struts on the wrong sides. Unbelievable ! It flies great now ! It still puzzels me why the wings are pitched up so much farther than the wings on my 2 biplanes, and my new little Nitro Models Pitts as well. It does fly great now though. He just has some extra cabane holes in the fuse now, no big deal... He's in hog heaven now, and I feel alot better about finishing my Pitts up. He said he put them on just like the picture in the manual shows, and it was apparantly wrong. My manual is even worse than his... Sure glad my Pitts struts only fit one way...

Hi;/That incidence problem isn't only related to your steerman!When Sportsman out with there Waco it was possible to putthe Cabanes on backward too.Result was about like yours!Word got out and the rest of us checked how we put them on and no more problem!!

I havn't looked at the cabane pic he's refering too in his manual, but I can believe it. My manual is terrible, but now I find out that our planes didn't come from Nitro Models, but came from a different distributor, or clearing house. My Pitts for instance came with full wheel pants, where the Nito Models Pitts just has those little goodies behind the wheels. With all these different things coming out of China, it hard to tell what your getting anymore. lol The model quality appears to be wonderful, but the manuals are just awful... With shipping and insurance and tax, my little Pitts came to about $225.00, but other than the full wheel pants, it's identical to the Nitro Models Pitts.

I don't mean to be sarcastic, so please don't take this the wrong way. Are you using an incidence meter? Get all the exact info together so we can help you better.

I believe you when you said the CG is where it is supposed to be.

He resolved the problem.

He had the interplane struts backward, which puts in WAAAY too much incidence.

Nope, but I knew it wasn't right. It's fixed now, and fly's great ! It rips with the LA 46, and practically lands itself ! Cool little plane really... I hope my new little Pitts flys as well, and that the Saito 56 pulls it good. It sure looks good ! I just wish the manual was a little nicer, and had a little more info, like the incidence specs. Maybe there so precise because of the lazor cutting, that it isn't necessary. I'd like to think so...

Is that what their called ? Interplane struts ? I thought they were cabane struts. Or is both correct ? I also heard Cabin Struts before...

Which Biplane do you have?

The NP 40S Challenger?

( I destroyed mine last weekend, but it sure flew nicely, for a WHILE! ).

Mine is called a Pitts 50. Came with full wheel pants. Manual looks like a copy.

Wingspan?

Where did you get it?


I destroyed mine when I encountered some engine sputtering during takeoff.

I wasn't getting climb, so I pulled back on the stick, forgetting that I had flipped on high rates after the prior landing as I felt that I was not getting as much elevator as I usually like....

MISTAKE!

The Pitts floundered and snapped hard right into the ground.

Too bad, the little 42" plane with the .46 TH engine screamed.

It probably went lean, you should have pulled the throttle back to about half and leveled out. I lost many an airplane like that. Remember the pull the throttle back thing, but don't forget to level out too... I recently lost a Cessna 180 Skylane the same way. I was taking off, had just switched from 20/20 to 15/15 fuel, and a guy fired up his 2 stroke as I was headed for the runway. I hit the throttle and it took off, then went lean, but I couldn't here it slow down over the other engine. I just saw the plane stop and fall. lol Oh well... The Saito 56 and electronics are going in the Pitts now...
I really don't know where my hobby guy got the Pitts. Some clearing house in Chico, or Sacramento, Calif I think. I asked him the other day, but he couldn't remember...

OOPS ! The wingspan is 42 1/2 inches...

That's the same size then.

Mine tracked nicely and flew very well.

Keep those rates low when you maiden it and use at least 20% expo ( except possibly on the rudder ).

No way... I never use expo... expo feels creepy to me...I set the throws by eye, and head for the sky and trim. I only use the rudder for hammerheads, and pitching sideways to slow down for landing sometimes. Im not big on stunts at all. I like to just fly around and land alot. Landing is my favorite thing. I always set my high rate elevator just below the point where they snap out of a loop, and high rate alerons to a 1 second roll. I like a good amount of rudder too, because these short coupled biplanes will keep ya busy after touchdown, or ya wind up playing wing tip bongo's, or hopping sideways down the runway. If a plane handles well on the ground, I get bored. My Super Skybolt fly's great, but it lands and rolls out too easily to be fun for me. It's simply too big and long to be fun. My Kyosho Super Stearman 40 is fun, but it's not quite squirlley enough for me anymore, and thats why I got the smaller and shorter Pitts. I guess we all like different stuff, and I like little tiny ill handleing biplanes the most. Large, good handeling planes bore me to tears. I don't mind test flying them for folks, but that's it. I do most of my flying at 1/2 throttle, and usually land 10 or more times per tank. I think the little Pitts will wind up being my favorite plane, especially with the Saito 56 on it. It should use very little fuel, and im all for that !