PopPhil

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There are a lot good articles on cg on biplanes. I used a formula that I found years ago, and it came out at 4 7/8 from the leading edge of the top wing. Thats with the correct incidence on the wings of : top wing -1 degree and the bottom wing +1 degree. 1st flight put the elev at neutral. Will try to find the info web page and post it.

PopPhil

My Feedback: (8)

Hope this helps works for me.[img][/img]

bps

My Feedback: (3)

Thats the formula I found most helpful. Thanks for posting that again as I could not find the link.

Paul_Barsamian

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Thanks guys, I do have an incidence meter, I'm probably goin to get her assembled tonight. And check incidences and double check the actual cg as well. Will report back tomorrow.

Spaul302

I measured the CG again and it falls about 5 1/4 inches on the top wing. It is still a tad tail heavy, but just how I like it. That is with an RCG 26CC up front. Here is a not very good quality video of part of the flight immediately following the CG measurement. You will notice that this plane needs more rudder to do any more than simple aerobatics, so that may be my next mod... I attempted a pop top and a hammerhead, but both suffered from the lack of rudder authority.

[youtube]http://www.youtube.com/watch?v=zGh1_ffUDTY[/youtube]

Paul_Barsamian

My Feedback: (5)

Thanks man.

Love the smoke on the video. I think I've pretty much talked myself into adding a smoke system. Based on reading up on the RCG engine you mentioned using, I think I'm only about 6-8oz off of where you are weight wise up front. I also used a single elevator servo (Hitec 5945) instead of duals and moved my throttle servo and battery up front. When I get back in town I'll get it assembled again and try to rebalance and check wing incidence.

Agreed the rudder is probably not going to be statisfactory for me, part of the issue with it is throw, the elevator gets in the way before I can get enough movement into it. I'll analyze and start a thread here on what the remedy might be, interested in your all input.

Spaul302

The amount of throw is the problem I have with it as well. I may try to widen the elevator opening to obtain more. I think it has plenty of surface, just not enough throw. I will let you know what I come up with. Ailerons however, are adequate and I am happy with the roll rate. See the video below for a demonstration of that.

In regards to your balance, I also have the smoke pump mounted on the firewall. That is another three ounces in addition to the ignition and engine, fyi. My videographer was not the best this trip. Weather dependent, I will get my wife to film some passes that will result in much higher quality in the near future. I hope yours figured out, it has been a blast to fly the few times I have had it out.

[youtube]http://www.youtube.com/watch?v=fkkNL-QrztI[/youtube]

Spaul302

Well, not to prod an old thread, but...

I always looked at this plane and said "it needs something." I think I figured it out.

That's right, Flying wires! My wife was on a girls weekend, so I took the opportunity to equip the Pitts with all kinds of wires. I like the look, granted it is not done to the scale attachment points, but I was going for a more dramatic effect anyway. I used coated stainless steel fishing leader from Bass Pro Shops and metal landing gear mounts as attachment points.

I attempted to use solder clevises for the end of the wires, however I could not get enough solder to grab to make a reliable connection. I ended up using crimp connections on all points.

Let me know what you think!

Paul