BOUND_4_HELL

My 1/3 scale Pitts special must have been built on a Friday afternoon after a liquid lunch. My first few flights were iffy at best, the plane wanted to pitch up even with 11 clicks of down elevator and was flying sideways to the left. After the first flight I increased down thrust, still pitched up. After the 2 flight I increased left thrust, still flying sideways. Our club president got his measuring tape out and notice that the tip of the wings measurement to the centre fuselage had a difference of one inch ( no exaggeration ) from the left wing to the right wing.

Took it home and shimmed the fore and aft saddle to straiten out the wings, back to the field, now the plane would fly straight but still pitched up severely. My club president back to the rescue, he suggested I check the wing incidence. I'm not a builder and I have only assembled ARF planes and never needed an incident meter, so I do not own one. The pres lent me his and sure enough the bottom wing of the Pitts was out. It had a negative incidence of 2 degrees. The top wing was only 0.5 degrees negative.

Took the plane back home and sanded the front of the bottom wing saddle by 1/16 of and inch and made a 3/16 inch ramp shim for the back of the saddle, to give me 0 degree incidence on the bottom wing. At this time I also used the incidence meter to level the bottom wing by shaving a little bit on one side of the saddle.

Now to the top wing, I had to elongate the centre mounting holes a bit at a time, so that the wing would pitch forward to a negative 1 degree incidence. Filled the now elongated holes with epoxy and then re-drilled at the proper location to give me a negative one degree incidence on the top wing

Checked the motor incidence and baked it off to factory settings 3 degrees down 3 degrees right.

Back to the field. Now the Pitts flies like a whole different plane, it is smoother more stable and less skidish. Although I still have a minimal up pitch, but I can live with it.

I have assembled 19 planes so far, all of them ARF models and never needed to check the incidence of anything. The RC guys Pitts manual does not mention anything about checking wing incidence or to make sure that your wings are the same measurements to the centreline of the fuselage.

For all you RC Guys Pitts owners, did you have the same problems ?????

I would like to know if mine was a bad build at the factory or if they are all bad ???

One more note, if you are still using the single centre elevator control linkages in the fuselage, do your self a favour and modify it to a dual control horn by installing a dual push rod system and take the control horns out to the elevator halves. I have run into one Pitts owner who crashed his Pitts because the factory horn inside the aft fuse broke off in flight.

Thanks
Geppino

PS: what do you guys think of my new colour scheme ??

mtwister

What you have run into are typical things that need to be checked when assembling a bipe, especially a prebuilt arf. All the planes are jig built, but they are not put together and incidences checked. Always check incidences on a bipe before 1st. flight. I had the 80 cc Goldberg Ultimate that was so far off when put together that it was a guarunteed crash without fixing it.

Rcpilot

My Feedback: (78)

I ALWAYS check the incidence and engine thrust when assembling ANY airplane.

Just because it's an ARF doesn't mean it's going to be perfect from the factory. Don't blame the factory. Blame the builder who slapped it together without using a tape measure and incidence meter before slinging the epoxy and drilling the holes.

Sorry dude, no sympathy here. It's your own fault for not checking it during assembly stages.

BOUND_4_HELL

Hi Rcpilot,

I was not looking for sympathy, you just stated the obvious, I screwed up. I’m not a builder or have any intentions of building from plans or a laser cut pile of balsa wood. I do not have the time or the motivation for it. I’m a flier.

Do not get me wrong on this either, I admire builders like our club president, as the are very knowledgeable and full of good information, and I hope that there are always builders out there to fall back on, when I need advice, it’s just not for me. If companies sold plug and play mid-size planes like the Pitts with good servos and motors, and I only needed to plug my receiver in, I would be the first in line to buy one.

My intention in posting was to let other RC Guys Pitts owners know that the wings may be a problem. I bet you would be surprised if you took a poll to see how many guys in this hobby are just ARF assemblers like me. I belong to two clubs and half of the members in both, mostly new to the hobby like me have never built, they just buy ARF or RTF and do not own an incident meter.

I have assembled 4 Bi-Planes so far in my short three years in this hobby, a GP PT-17 Stearman, GP Super Skybolt and a Goldberg A300 Ultimate and they all flew straight and true out of the box. The RC Guys Pitts has all the holes drilled in the wing struts, cabanes, and the top wing mounting bracket. The bottom wing saddle is already there, all you need to do is bolt it together, just like all the other ARF Bi-Planes I have assembled. All I was trying to say is that the quality was not there in this ARF kit.

Geppino

joseph.batson

I have a Skyshark Christen Eagle that I maidened a little over a month ago, that did the same thing. It was totally unexpected that when it lifted off, it went up and to the left. I too thought the thrustline was off or needed more down and right thrust, think I will check the incidence on the wings.

BOUND_4_HELL

Hi Joseph,

I just learned this about Bi-Planes. Negative incidence on the bottom wing will make it pitch up. It goes against the grain, but because of the drag factors involved it acts opposite of what you expect. I also confirmed it on the simulator and sure enough negative incidence on the bottom wing pitches up and positive incidence pitched the nose down.

Hope that you can correct your problem.

Geppino

joseph.batson

After you made adjustments, what did you end up with on top and bottom wings incidence?

BOUND_4_HELL

The bottom wing should be 0 (zero) and the top wing should be -1 (negative one) degrees. This configuration stalls the bottom wing first and you get gentle stall characteristics. On a stall it just gently points the nose down like a trainer and start flying again without dropping a wing.

Bound_4_Hell
You can never have enough power, as you can always throttle back.

BOUND_4_HELL

I finally got the Pitts flying fairly well, not what I expected from a Pitts, but it will have to do, as I did about a dozen adjustments to the engine thrust angles and a half dozen adjustments to the wing incidence, it been a real pain in the butt to tweak, here is what I settled on.

Down thrust >> 3 degrees (factory recommended setting)
Right thrust >> 3.5 degrees
Bottom wing incidence >> positive 0.5 degrees
Top wing incidence >> negative 1.5 degrees

The quality of the kit I got was very poor, I had to sand and shim the bottom wing saddle in both directions to get the wing centred and at the proper incidence, it came from the factory at negative 2 degrees. It has very cheap covering, if I do not crash it, I will recover it this winter. Its coming apart at every seam and splitting at the wing ribs and fuselage ribs. I have been patching it up all over the place.

Once I got the thrust and wing incidence in the sweet spot, it now flies a lot better than the first few flights I had with it, although it cannot hold a candle to the other bi-planes I have flown. It's definitely the worst flyer out of the 4 >> Stearman, Skybolt, and Goldberg Ultimate.

It knife edges slow and low, but has a lot of coupling in both aileron and elevator with some practice I have trained my thumbs to get it fairly smooth. Rolls are axial with some differential programmed in the ailerons, but loops are not inline, I think that is just a defect with my airframe.

I have not been able to do flat spins, either upright or inverted. I'm at the middle of the C of G range, so I will now start to move it back to see if it will flatten out on spins. The best flat spinner I have flown is the Super Skybolt.

Flying inverted is a real hand full; it needs more that a half elevator stick to keep it level.

The Pitts excels at tumbling and it's a real crowd pleaser when I do them at the field.

I give the Pitts and overall rating of 3 stars out of 5.

This is short clip of my Pitts in knife-edge with a 50DL and a 22x8 Xoar prop.

http://www.youtube.com/watch?v=QLWrG0ZPCjo

Geppino
__________________
BoundForHell
You can never have enough power, as you can always throttle back.

jtsails

My Feedback: (2)

I bought one of the first of these planes and I had the same problem. I am sorry to see that they haven't made any adjustments. I also found the covering to be low quality, doesn't like to stay attached and has faded very badly. There is an old thread in the Giant scale forum about these issues.
james

BOUND_4_HELL

Hello everyone,

I do not want to give a totally bad impression about the Pitts. It's now flying really well, it just took a long time to find all the sweet spots with all the incidence and thrust variables.

I'm not a builder and a real hobbyist (AKA a builder) would have never complained about the wings being way off, he would have fixed them on installation. I did not own an incident meter, but I do now, and everything worked out in the end.

My DL50, although it's burbling, is still performing beyond my expectations.

Here is my new video with the DL50 and Pitts Special doing some knife edging, through the setting sun at Humber Valley flying club.

There was not a cloud in the sky that evening, the spectacular red hue in the video is from the smog in Toronto.

I shot it in High Definition. You can watch it in High Quality by clicking on >> Watch in High Quality link just under the video window on the right hand side just below the volume button on the YouTube site.

http://www.youtube.com/watch?v=1Cb0ym4Hw9E

Geppino

Here is a photo to wet your appetite for the video.

gjmjoe017

My Feedback: (1)

I have had two Pitts,Kyosho and the GP Pitts and had no problem with the incidence in either,but the guys are right,it should be checked to make sure.I do think these things should be shipped out with all of those things done correctly.That's what we pay for.But as every one says,better safe than sorry.Good luck and hope you have her flying better!!

BOUND_4_HELL

Hi gjmjoe017

I totally agree as an ARF assembler I expect that all of thrust and wing incidence variables should be done for us, so we can just bolt it together and fly. Maybe I'm asking for too much, but that is my expectation, and as you said, it's what we pay for. In the end every thing turned out great, it just took a lot longer than it should have with an ARF.

BTW I did contact RC Guys on this problem, both by phone and by e-mail. Dan is a great guy to deal with and he also said that he would make a change to the assembly manual and include a check for the wing incidence, so this kind of trouble could be caught when assembling. The problems with my kit I believe all stems from the bottom wing saddle, as that is where I needed to sand and shim to make the wings fit correctly. Other than giving me a new fuse, there is nothing that RC Guys could have done better. I did not expect a new fuse, and I never asked for warranty.

I have a friend who has bought the Super Decathlon and the AG Wagon kits from RC Guys and both of those kits had no problems. Although, he has complained about the quality of the covering.

I'm sure that my kit is not the norm for RC Guys. My intension for starting this tread was/is to alert other ARF assemblers like me that there could be a problem, so they would not have a hard time on the maiden flight like I did. To trim the Pitts on the maiden I had 11 clicks of down elevator and 8 clicks of right ruder. The first few flights and landings were iffy at best.

The story I have told here is my experience and review if you will. Not intended to bash RC Guys. My final thoughts......
The Pitts is now flying superbly, and the question to ask is; WOULD I BUY ANOTHER PITTS from RC Guys..... The answer is YES..... For those of you that are sitting on the fence JUST DO IT, in the end the Pitts turned out to be a real good flyer and a crowd pleaser. I take it every time I go to the field now.

Here is my new video with the RC Guys Pitts Special and DL50 doing some knife edging, through the setting sun at Humber Valley Flying Club. There was not a cloud in the sky that evening, the spectacular red hue in the video is from the smog in Toronto.

http://www.youtube.com/watch?v=1Cb0ym4Hw9E

rack

My Feedback: (11)

seems the arfs are getting to large an advanced, some of you guys nead to learn the basics before waisting your money on an airplane that you cant get the most out of .
well good enough for me, may not be good enough for the people who think there watching someone who knows what he and his plane are doing as it careams toward the ground

esbjoern

Hello Bound4Hell,
Great post. I am currently building the GP Pitts, and I am very happy to learn from your experience.
Regarding the saddle for the lower wing: I will need to remove some 4mm of the front in order to achieve your incidence of +0.5degree, but this leaves only little material from the already disturbingly thin rib. Did you somehow reinforce that section?


I am using a DA50 so your experience with the DL50 should be directly transferable. Like what was your total take-off weight?

Thanks
/E

Tisoy909

My Feedback: (21)

BOUND_4_HELL,
I have been looking into getting this RC guys 33% Pitts recently and i'm concerned now since reading your posts. I noticed the color scheme of your Pitts to be different, (perhaps an earlier model?) from what i see now available through the RC guys site, is it possible they have also made the type of corrections with wing incidence issues that you encountered aside from simply changing up the color schemes? I too am aiming to use the DL50 as you have and for the most part have read nothing but good about this motor, well aside from the gripes of DA owners at my club. Anyhow, I have some experience with wing incidence issues, and also have an incidence meter myself, but in all honesty I dont think they should even sell the model with issues that will negatively affect the quality of its flight characteristics. Its one thing to build the model correctly another thing to have a hidden issue for the modeler to go and discver and be left to contend with it once he owns it. Certainly the looks of the model has gotten me, its definately sharp, but biplanes with wing incidence issues I have come across before on cheaper kits. I'm proud to say that im an EX-builder, atleast for now, and dont have the time or patience to correct issues that the actual builder/designer should have addressed in the first place. In contrast, if i break it, then fine, I can opt to rebuild the broken part and do a repair in that case, knowing atleast that it was a perfect model to begin with. Anyhow whats your input on this? If RC guys havent put attention to a model thats built with a wing incidence thats 2 degrees off i think i would just scrub the whole idea altogether. I like the youtube video of your pitts btw, saved it to my favorites a couple of months ago, didnt realize that was yours till just now.
Thanks,
Louie

BOUND_4_HELL

Hi esbjoern,

I did not need to reinforce anything on my RC Guys Pitts. Yours is a Great Planes Pitts, so you may need to reinforce. Please note that you may not have a problem, I think Great Planes kits are of better quality.... Make sure you find out what the incidence is suppose to be, as it may be different than the RC Guys model.

BoundForHell
You can never have enough power, as you can always throttle back.

BOUND_4_HELL

Hi Louie,

Although I was not the only one with this issue, others also reported that they had to tweak the incidence. However I also have run into and talked to RC Guys Pitts owners that flew their Pitts without tweaking anything and they flew well out of the box. I believe that it was an assembler at the Pitts factory that did not make the proper quality checks, and some got out of the factory with problems, as not all Pitts had this problem.

Mine is from the first run two years ago. It only came in that awful mauve/yellow colour. Some people commented that it looked gay, so I changed the mauve on the wings to a checker pattern. The new Pitts arriving now come in the standard red/white scheme or the black/yellow scheme, so you have a choice.

I have not heard or seen any posts that the new ones have any of the problems that I described, and as I stated before, once I got it flying correctly, it quickly became my favourite plane to take to the field, so go for it. It's a good flyer as far as Pitts go, and the DL has more that enough power to take it strait up as high as you want it to go, it’s fun spinning it back to earth

It sound like you have way more experience that me building them, so I cannot see you having any problems.

I recommend you buy one, you will not be disappointed.

I'm glad you liked the video, it was a lot of fun flying that day. Not a blade of grass was stirring and the smog made the sun that warm red colour at sun down. It was a perfect ending to a great day of flying.

http://www.youtube.com/watch?v=1Cb0ym4Hw9E

Geppino

adslparts

I also own this model with a DL50 engine and its the old colors which creates an issue FOR ME as far as visibilty. I am going to do something with the bottom wing to make it more visable. I had no problem with the incidence, I used a meter and was able to get it right the first time pretty easily. The covering is "chinacote". Mine started to peel from the 2nd flight and I have been adding clear packing tape all over the place. The other thing that should be echoed is DO NOT USE THE SUGGESTED ELEVATOR INSTALLATION INSTRUCTIONS. I reccomend that you move the elevator servo to the rear of the fuse and reinforce the wire joiner or just use 2 servos.

The plane is a very nice flyer and has rediculous power with the DL50. I agree with Bound4! I would buy another one! The good outweights the bad in my opinion. I guess for the amount they are charging, they could have done a little better on the covering, that's my only real complaint. Its a head turner, thats for sure, especially with smoke!


James
Fergus Falls Regional RC Flyers
Vice President.

adslparts

adslparts

Hi All,

I own one of these and am not the greatest pilot. I'm still getting use to it. Gotta do power on landings...can't just cut the throttle on final and expect to glide it in. Since the dl50 is just rediculous power for this plane. throttle management! I think I need to invest in a good digital for throttle.

Please note, the higher quality planes are always lighter and more fragile but biggest issue was poor glue work.

On the quality:

I had the landing gear rip right off on a soft landing and found the plywood was not glued in one side. I repaired it correctly by making a new part of ply and it survived a very hard landing that bent my gear and did some other damage. Lesson sI learned with this plane include

1. Reglue (CA) everything - this is very important! All joints need to be CA, also need alot aroud where the blind nuts for the wing go. I had that pull out on hard landing.
2. Make a top hatch for your engine box
3. Reinforce the elevator or use two servos5
4. Prepare for the covering to come off in flight , it kinda stinks
5. Don't use the clevis parts they include, go buy good ones
6. Install prop so that if engine quits it willl be horizontal (I use TBM 22x8)
7. Check the tightess of your prop bolts and yes its a pain if you have a spinner, but it must be done after a few flights
8. Works well with smoke system and has plenty of room for 2 tanks
9. Use a DL50 or 55

adslparts

Still have that same opinion? I've pulled back the covering on the fuse aft of the cockpick and there was loose wood in there too! Just hate to see a 50cc go in for shotty maufacturing.

keith124

My Feedback: (5)

I just recently built a super decathlon the are was put together badly quality controlI've built from china is not very good. I had to modify the plane alot . I've built numerous arfs before but nothing as crappy as an rc guy arf . sorry just my personal opinion

RonMcCormick

My Feedback: (4)

It's 2014 and the kit is still just as bad. Mine is sitting on the board with the finish stripped of. The covering is crap I will redo in Ultracote, I used three small bottles of CA so far re- gluing every balsa joint. I reenforced the engine box it had joints with no glue at all. I corrected the wing incidence by lowering the trailing edge of the bottom wing 1/4". I put three servos in the rear since I'm using a EME 60 engine if tail heavy I will move the rudder servo forward with pull-pull which I hate. Because I lowered the trailing edge of the wing I had to do a lot of work on the belly pan to get it right. The hinges are crap breaks very easy so I upgraded to Robart and increased to five on each elev and six on the rudder. (dont use any of those hinges) I love Pitts and for some reason this is the first one for me and I started flying in the 1960s. If I really like flying this thing I will build another from plans, the only way to get a nice Pitts of the older design, plenty of 12s I dont like round cowl Pitts, just me. You dont have to be a full blown builder for this kit but it helps. This is not an ARF in the sense of an Aeroworks Pitts which I could build in a week. I wish someone would make a nice 33% round wing Pitts ARF then I can spen my time flying not building or re-building.

a70eliminator

Alot of tinkering to change wing incidence on a bipe like changing the wing strut angles too so you don't get twist.
Anyhow, out of curiousity what does you pitts weigh ready to fly? I ask because I've built 2 from scratch and have yet to hit the17lbs mark with 50cc engines.
Mine are from GP weeks but very similar to pitts. The pitts arf specs advertise 12-14lbs! thats without engine right?