Chris,
When i checked my bird, before i flew it, if i remember correctly, the wing and the stab were at 0-0. Evidently there is some other issue with this plane. I believe it could be because of the short tail moment. Maybe Great Planes designed it at 0-0, but it sure does not fly that way. Could be that is why pattern planes have such a long tail moment. All planes are different, some need to be at "0", others need incidence, some negative, some positive. I guess you could say "its the nature of the beast". All i can tell you is with my front of the wing down, that half degree, it flies perfect.
I guess you could add nose weight, that would help it fly with less elevator trim, but i prefer to have the CG where it belongs.
Hope this is of some help to you ....... Good luck, Paul

Hey Paul,
I think I'm going to confirm your findings. How did the plane fly at 0-0 on the knife edge? Did it pull tothe belly?
Rick

Rick,
I can not give you an answer to that, as the plane now has the 1/2 degree down incidence in the wing. i don't recall any pulling to the belly in knife edge, but i was not looking for that either. I am going to fly it today, i will see what it does on knife edge.
Let you know later. Paul

Paul,
Have fun, wish I could go - you know how this work thing gets in the way.... How did you get the -1/2? sand the wing saddle? More important is that you got rid of all the uptrim in the process, is this correct?
Rick

Rick,
just got back from the field, bird is flying great. I did put it on knife edge, and it does pull to the belly. Not bad though, i can live with it!
It does fly great inverted though. I drilled out the front dowel holes down, about 3/32" then made a new plywood plate ,and epoxied it in behind old bulkhead, to accept dowels, then filled in gap in fuse with epoxy& micro baloon mix. I guess you could sand the rear of the saddle too, six of one half dozen of the other, LOL
Yes, the stab is now flying at level with no down trim!!
Good luck, Paul

Gentlemen,

The thrust angle is VERY VERY VERY extensively tested and is 100% accurate. Thrust angle is not set to give you a nice looking stab/elevator mate, it is set to keep the model from changing pitch trim when power is applied. As someone stated along the way, if hte model does not pitch down hard, suddenly, upon pulling back the throttle, then the model does NOT need more downthrust.

It sounds to me like a wing incidence/seating problem, and I am passing this thread along to our R&D manager immediately for his research and to check the wing/stab measurements on the flying prototypes and post-prototype models. Nearly every member of our R&D staff have one of these, and love them, so we should have plenty of data to work from!

Paul, I'm sure it was an innocent mistake if your email was not responded to. We answer literally thousands of pieces, and mistakes, system failures, etc, can and do happen. Please do note that your indication that we are "dead wrong" about the thrust angle is inaccurate.

Sincerely,
Mrs. AnnMarie Cross
Senior Manager, Proprietary Services and Support
Great Planes Model Distributors
[email protected]
www.greatplanes.com
www.bestrc.com
NO AUTORESPONDER

Thank you AnnMarie for taking the time to answer this concern here at RCU.
Although I haven't heard your problem before in my neck of the woods guys, I appluad your efforts to find the fix.
Now that AMC is on it, I'm sure you'll get the answers you need from GP.

Good luck,

Wow Ann,
Thanks for the Info. I have duplicated Paul's problem. New and out of the box 0-0 the plane needs a significant amount of down trim for straight and level. This really caused my plane to pull to the belly in knife edge.
I need to get that down trim out of the plane (I like the CG as it is pretty nutral now) to tame the pulling to the belly on knife edge. I'm going to try -1/2 incidence like paul, but I'll wait to hear what you say.
Thanks
Rick

Annmarie,
Thank you for taking the time out of your busy schedule to comment on our posts. I would certainly like to have some hard facts, as to why this plane is designed this way. Please do not get me wrong, as i am not bad rapping GP, i think you folks have done a fantastic job on this airplane, as i have commented in my earlier posts, there is "no way" I could have built and covered this airplane for the price I paid for it.
I think my biggest gripe was before i flew the plane, i noticed the huge amount of "upthrust" in the firewall, so I did notify you folks, and was told that it was designed with that much upthrust.
So when i made the first flight, unexpectedly, the plane pitched up nose high on take off, and i nearly lost it! I had to put 28 clicks of digital trim in it to get it to fly level. So i started experimenting with the thrust angle, I even had the engine at 3-1/2 Degrees of down thrust. this did not cure the problem, as i still had to put down elevator trim in the plane. So this told me that i also had an incidence problem, which i corrected by dropping the front edge of the wing.1/2 degree. I put the engine thrust angle at 1-1/2 deg. down thrust. The plane now flies very respectable.( Weight and balance were checked numerous times, and are to specs.) I believe the plane has two problems, thrust and incidence, as i had to change both on my plane.
When checking all the posts on the web, i find out that it is not an isolated problem with just my plane! Like i said, earlier, i know of 5 of these planes that i have seen personally ,with my own eyes, that have the same problem.
Like you just stated yourself, you believe it is a wing/incidence problem too. It is good to know that you are making your R/D guys aware of this problem, I hope you post a reply as to what they find out, is causing the plane to require lots of down elevator trim.
Ann, I do apologize for making the statement that you guys were " dead wrong", that is not accurate, as you stated. but i guess by making that statement, i got Great Planes attention. As for my emails, not being answered, you could be right about it being an innocent mistake.
Again, thanks for taking the time to answer our posts, and also my thanks to RC Universe, for such and outstanding job they have accomplished with this website!
sincerely, Paul

Paul,
Being married to the test pilot, trust me when I tell you that the stock thrust angle of the models that were sent as "ok'd for production" was dead on. That is mike's biggest pet peeve and he works VERY hard at it.

I firmly believe what you have is solely an incidence problem, assuming your model has the called for 1 degree of up and 2 degrees of right thrust, as that configuration was PERFECT for the test flying.

I suspect there is something wrong with wing saddles or with stab saddles, and have folks looking into that now.

Please note that CG positioning is CRITICAL to how much elevator trim you will need and even more so on how much the model pitches to the belly in knife-edge.

Sincerely,
Mrs. AnnMarie Cross
Senior Manager, Proprietary Services and Support
Great Planes Model Distributors
[email protected]
www.greatplanes.com
www.bestrc.com
NO AUTORESPONDER

AnnMarie,
Again, thank you for your reply. It is great to know that, a large manufacturer, such as GP takes a very real concern about their products. Some companies would not even have the decency to reply.
I guess you could say that my mission is accomplished, as you are now aware that there definitely is some sort of a incidence problem, because of the different posts you are reading, that all say they have to put in down trim in the elevator.
My bird did not have one degree upthrust, it had better than
2-1/2 degrees of up thrust. I am not so sure as to the fact that it is good that i have 1-1/2 deg. down, i am going to put the thrust at the required 1 deg. UP as you suggest. I am also going to check my right thrust, as it looks to be more than the required 2 deg.
After that, i will see if there is any change in level flight, when power is chopped, or added.
I will inform you Via email.
Keep up the good work Ann. I have heard rumors that you new Patty Wagstaff Extra 300 is an AWESOME airplane!!
sincerely, Paul

Hello AnnMarie and Paul,
I would also like to second Pauls comments about the quality and being able to build this model for the same money. I am very happy with it. When I set mine up I Put in 1/2 degree of upthrust before I drilled the mounting holes for the engine. (I was actually aiming for 1, but when all was said and done, it was 1/2). With )on the wing and 0 on the stab, I needed considerable down trim, maybe over 1/2 the trim on my standard transmitter and it was definitely visable upon inspection of the stabilizer after flight. I plan on putting some negative in the wing incidence and will let you know how it works.
PS I think your customer service department is top notch and doing a fantastic job. I'll be a GP customer for life.
Rick

Hello friends,

I want to get in this discussion too. I know I might be late but need to confirm many of the same issues as the other fellas. I got this plane this winter and fell in love with its style, looks and great price. There is NO WAY anyone can build this plane for the price of the ARF. Keep up the great deals GP!!!

However, I concure with the guys about the flight characteristics. I had it set-up by the book. The CG was right on, the mount flat on the firewall, wing and stabs at 0 degrees. I was using the suggested ST 2300 and Trueturn 4" spinner. What a beauty (took third place at the mall show)

On the first flight the plane took off in about 15 feet pulling up in to a loop. I added a ton on down to get flying level. At first I though I was tail heavy. When I cut the power it dove to the ground. I was fortunate to still have it. I began to do research on the net when I began to read of the possible thrust problems. Now on the sixth flight I am getting closer. The engine is 1 degree down, tail still has down in it, and I added three turns of the aileron linkages in to give it a more positive incidence. I now flies straight in power and cut power, tracks straight in a 90 degree dive, but still pulls to the belly on knife edge. I have some flight time on video that I am going to make digital for you geeks out there.

Personally I would love to get my hands on one of those the GP guys are flying. I want to compare, cause something isn't right. Don't worry though cause I still love the plane still a little shakey when flying it, cause I am not sure what it is going to do. So if you are ever in South Central Indiana stop by our field it is very nice. Paved runways picnic area, great people, and great place to fly.

Ricmussman,
Thanks for your reply, this is just another one for the record books. I guess, i opened up a can of worms for GP on this one.
But I am sure that they would want to know if they have a problem with one of their products. I too wonder how this one got by their R&D guys, as ALL the Giles i have seen have the same problem. I am glad that AnnMarie had the decency to reply to our posts. She was willing to go way out on a limb, by saying that there is an incidence problem.That just shows That GP IS a great Company in my books! It will be interesting to hear what conclusion their R&D guys come up with....Paul

Hi! fellow flyers! I got to reading all of your suggestions when I saw the GP Giles 202 post, I have had that same problem about almost stalling on takeoff, I get up good speed and all of a sudden mine wants to go straight up, I will try some of your tips, In the meantime Rickp I grew up in the southern part of Hicksville near Levittown... Wishing Lane off of Jerusalem Ave. near Scooter Lane, I have moved in 1978 and was not into Rc until about a year ago, where do you fly at in that area? I haven't been there in about ten years and everything was so changed then.

Guys,
I put the engine thrust at 1 degree UP, as AnnMarie says is designed for this bird. Checked right thrust, it is exactly at 2 degreees, like GP states, that is designed in. Flew the bird again, it actually seems to fly better with the 1 deg. up thrust! But plane is still turning right.
Chop power, no difference, add power no difference, so thrust seems to be no problem,(not sure it needs 2 degr. right thrust)..I think i will do my own R&D on this, as i have a gas engine,which does have a little differeent performance than the methanol motors ..The plane still pulls to the belly in knife edge....
The 1/2 degreee, that i dropped the front of the wing seems to be essential for level flight , with no trim in elevator!
There are so many things that affect flite performance, that i have to take one step at a time in making changes.. Oh Well, i should be used to it , as i was the Tecnician for NORVEL, which is a totally different ball game , as they are 1/2 A size! Okay guys, don't email me with your small engine troubles, as SIG now handles all NORVEL products! Thanks ,Paul

We have two links for setting up your planes:
http://www.geistware.com/rcmodeling/...tics/setup.htm
http://www.geistware.com/rcmodeling/...lane_setup.htm

Enjoy!

Rick, thanks for your input, I have tried the power off dive, and its fine, no pull to either belly or canopy, only pulls in KNIFE edge to the belly.. We will have to wait and see what the GURU's at GP come up with, its their bird, so hopefully they will come up with some logical answer......Paul

Hey,
That's not far from me. I live right off Jerusalem Ave near to Hempstead tpk. We fly at Ceedar Creek, near the water on the south shore. It's just oposite Wantaugh Park over the Wantaugh pkw. Weather is tough though. Cold and windy, but we make due ;-)
Rick

The day before i was going to test fly my gp g202 i read this thread and became concerned.I went back and check my thrust on the engine and it was over three degrees plus.I put two washers on the engine mount which was 2mm.checked it again and it was 1 degree plus.i flew it the next day and it flew great.The only trim i had to make was one click down.our club ace said it was the most stable plane he has ever flown.Paul Thanks for all your imput and thanks to all who gave imput it was a great help to me.This is a fun plane. Roy

I've got one in the box just waiting to go together if I decide to. So if the answers come out here it would be great. What would be a good gasser for it? Thanks!!!

Folks,
The prototyes -- and all of the R&D boys -- birds are all as follows:

engine +1
wing 0
stab +1

and all fly beautifully as far as thrust angles.


We are actively researching why some customers' production birds have such varied thrust angles.

The model DOES have a pitch to the belly in knife edge -- as do most aerobats -- which requires mixing to resolve. Yes, design changes could have been made to resolve this, but such changes affect other flight parameters which were given priority. Using the proper CG has a huge effect in minimizing such a pitch.

Hello Annmarie,
OK, so positive stabilizer incidence is the LE of the stab up? This would make sense why on our planes with 0 wing and 0 stab we need negative in the wing. Kind of hard to change the stab once it is glued in. I also have 1.5 deg up. I will change the wing to -1 degrees ASAP and let you know how it flys.
Rick

Rick,
yes, wing -1 to a 0 motor and 0 stab.

This plane has a lot of up thrust. I think the company did this so it would be easy to hover. The up thrust makes it hard to trim as you found out. I put everything at o and the plane was a dream to fly. I put the cg. a little on the tail and added a O.S. 160 18x6/10 and burned holes in the sky all day.