CADgeek

I am nearly finished building a 64" Sterling Stearman PT-17 Kit. Does anyone have a good set of starting control throws for this plane? This is my first Bipe so I don't have any baseline to start from. I am using a Saito .91 engine and expect the build to come out around 12 pounds. If anyone can even tell me what they are using on similar sized Bipes that would at least give me a starting point.

CADgeek

Wow, I would like to thank everyone for the zero replies. Evidently people who fly biplanes don't read this forum, or know how type, or something.

Lnewqban

A little bigger model, but you could use it as a reference for the first flight:

http://manuals.hobbico.com/gpm/gpma1350-manual.pdf

CADgeek

Thanks for the info LNEWQBAN, The Super Stearman, if I remember correctly, has ailerons on both the bottom and top wings so I don't know how to relate that but the other controls should be similar. Thanks again.

Crash Campbell

Hi CADgeek,

The following set up is for a CG Ultimate which has ailerons on the top and bottom wings, it's powered by a 125ASaito. You should also be aware that I like responsive aircraft.

Ailerons 14%
Elevator up 18% down 14%
Rudder all I can get, yes it will knife edge loop.

If like most of us if you err on the side of caution with the CofG and fly the first few flights with a slightly nose heavy CofG you may like to add more up elevator to "hold the nose up" in the flair.

Bipes have a lot of windage compared to most airframes and you need to fly with a bit of throttle until you are sure you have the strip. This is obviously exacerbated as the wind increases, assuming you are landing into it. Don't cut the throttle and glide in as you will have a heavy landing. If you have a deadstick get the nose down immediately and glid fast!!!

Hope this helps,

Colin

SeamusG

Control throws for a Hog Bipe:
Aileron - 5/8" up and down
Elevator - 3/4" up and down
Rudder - 1 1/4" left and right

CG stuff per the manual:
25%; 3-5/8" Good place to start if this is your first biplane.
30%; 4-1/8" Better elevator response and quicker snaps.
35%; 4-5/8" Approach this CG with precaution. Inexperienced pilots may find this to be to extreme for their ability.

The Hog Bipe finished at 8 1/2 lb and uses a Saito 100.

CADgeek

Thanks a bunch guys. I have the Real Flight Simulator and have been practicing with the Stearman, but simulators only go so far. I have noticed the need for throttle to land cleanly as the plane slows down like it has the brakes on. I like the idea of balancing a little nose heavy also. These settings will make me feel more comfortable for the first flight in about three weeks (After vacation to FL).
Good Flying!

Lnewqban

Welcome to Florida, CADgeek!

Perfect time for vacations.

Gray Beard

My Feedback: (-1)

Never saw the post?? I would like a bit more power on that Bipe but that just a choice. Throws are pretty basic for planes until you get into 3-D. I use a degree meter on all my controls except rudder. I get all the rudder I can, the others I set up at 12 degrees up and down for high rates and 8 degrees for low then as I fly the plane I decide if I want more or lass. On bipes I often add Diff to the ailerons so I may set up my ailerons to 2 degrees more up then down to help the roll rate. Yes, Bipes do slow down a lot faster so you can shorten your approach.

Charlie P.

If I told you my 65", 13 lb. biplane has 2-3/4" up/down on the elevator, 5" left/right on the rudder and 1-3/8" up/down on the ailerons would it help you at all without knowing the chord of the ailerons, strip or barn-door style, or the strengths of the design?

I've never owned a Stearman, but I bet 1/3 of those throws would be plenty. Tear up the sky, tiger.

CADgeek

Gray Beard, Thanks for the input. That kind of info/preference is exactly what I was looking for and very helpfull. I typically build with extra power, but since I aim to fly this plane as close to scale as is practical, I decided to go with the .91 instead of the 1.20 I was originally going to use.

Charlie, sarcasm noted and appreciated. What those figures do tell me is that you sound like an experienced pilot, and possibly builder, so you more than likely have an opinion about initial setup on a plane like this. That is all I am trying to establish from this post. A comfort zone to start out with.

P.S. I apologize for the intended tone of my second post but I have to bow to my wife who said, "It's easy to ignore someone who is asking for something, but watch how many stand up when their apathy is acknowledged!". I promise not to do it again.

Gray Beard

My Feedback: (-1)

This is a forum, no one is required to answer, if no one has set up or used your plane combo they may not want to give false information. That even happens here sometimes, usually not. Charlie is yanking your chain or flying 3-D but also stating some fact. Just because others have there plane set up with throws they like doesn't mean you would like them at all. I use a lot of Expo, I have friends that hate the feel of my planes. There is a lot of pilot choice in plane set up.
Here is what is said in a throw meter add from Don's hobby shop, they are big into giant scale and 3-D planes.They use a degree meter instead of inches because inches are meaningless, a 1/2 inch deflection on a 1/2 inch wide elevator is far different then 1/2 inch on a 6 inch wide surface but a 12 degrees deflection is the same reguardless of the planes surface size. They also use 12 and 18 degrees as there starting points. I discovered I liked about 10 and 8 but I often set up at 12 and 10 depending on the plane and then after flying I start adding and subtracting my throw rates as needed for the plane. You can buy meters from Don's for about $25.00 but I make my own. I make them in right and left and use them two at a time to make sure each half of a control surface is zeroed/level/ equal. The instructions usually give you a starting point but I have been using degrees so long I no longer bother with the kits starting points, I just know what I like.