wingnutEOD

Lo All,
I am a novice RCpilot looking to get into flying pattern as a means to gain/hone my flying skills. During my research I've read about using various maneuvers to help determine the required adjustments to an airframe that result in neutrally stable flight characteristics in all flight attitudes. (Trim sheet maneuvers and adjustments). What I have not found is an explanation or example/case study of actually using this method. This gives rise to a couple of questions for me:

1. At what throttle setting(s) am I flying these maneuvers? If I were to mechanically trim for SaL flight at 50% throttle, then at 51% to 100% I would have positive VS flight (not SaL anymore).

2. Is going through the trim sheet an iterative process? ie. After trimming for SaL flight you are to adjust the CG via one of two maneuvers. This CG change results in a different trim requirement for SaL flight than before, so do I go back and start over with the new CG position?

I am highly interested in any input the community has on this topic. I look forward to your replies.<o></o>

Jetdesign

My Feedback: (8)

Good questions.

1) the speed is decided by you - trim your plane for a comfortable cruising/flying speed. In pattern, it is not a requirement but we strive for constant-speed flight. Find a speed that gives you enough time between maneuvers but is fast enough that the plane is flying with authority - not fast, but fast enough that a pull or roll won't put the plane near a stall.

2) it is iterative. If you go through and end up changing your CG, you should go through the process again, as changing CG will affect almost everything.

Trimming takes a long time. I am still learning the art of properly trimming a plane - with the ARF I have, I am limited to what adjustments I can make so I have to modify the trim sheet/process to fit my plane.

speedracerntrixie

My Feedback: (29)

Having your wing and tail incedences set correctly and your CG dialed in will make your airplane fly SaL at anything from 1/4 to full throttle. My default settings are wing at +.5 degrees, stab at zero, engine up at zero and right 3 degrees. Set CG to around 30%. With these settings I fly and adjust CG according to what elevator trim is required. If up trim was required then I move the CG back and opposite for down trim. At one point you will find the sweet spot and you will require no elevator trim. For me that is where I like the CG but for some that is a little aft. Once you have the CG set you can start messing with engine thrust and mixing. Don't bother with anything else until you get your CG lock in as if affects everything else down the line.

MTK

I see you live in Georgia....You have several very good guys out your way. Emory Schroeder is one....Chris Hinson (Mr Extreme Flight) is another

Not sure where exactly Glenville is but if it's close to Mack Hodges field (home of the SEFF) definitely give Mack a visit.

Your best bet at getting really good examples of what you seek is to actually have experience guiding you. FWIW2U

wingnutEOD

Thank you all very much for your replies. Informative is only the start. Today I purchased the Great Planes Reactor .46-.70. I will test my knew begotten knowledge (imparted by you fine gentlemen) after some dry runs through RealFlight 5.5. I'm looking forward to the results.

Speedracerntrixie - In my studies I haven't come across a description of how wing (and stab) incidense affects flight performance. Do you happen to have a reference on hand? Also, the idea that SaL flight trim can be achieved at such a wide range of power settings doesn't make sense to me. Could you explain what causes that ability?

gaRCfield-Thank you for breaking it down for me. Your response set off the "I can get this done" spark in my head and really provided the push that I needed to completely commit to Pattern flying as something I should be interested in persuing.

MTK - Glennville is on the western border of Ft. Stewart, GA which is about 35 miles southwest of Savannah, GA. The closest RC airfield that I've found has been in Statesboro (home of Georgia Southern) and is the home field for the Ogeechee Aeromasters. We're a small club, but we have some beautiful land (if not dangerous... there's a tree out there on the back side of the landing field that has claimed more than it's share of balsa wood. Some folks hate the thing. I love it. Not only is it something of a challenge to maneuver around while flying the pattern for landing, but the dang thing has been struck by lightening from tip to tail and is still making leaves.)

speedracerntrixie

My Feedback: (29)

It's fairly straitforward. Most will set up an airplane too nose heavy. This results in up trim. That up trim only works in anorrow speed range. Faster and the airplane will climb, slower and the airplane will dive. Get the CG right, eliminate the need to ANY elevator trim and the airplane will track strait at most speeds and be less affected by wind gusts. This assumes that you have it set to 0-0-0. Or in my case I like to set the wing at +.5 and everything else at zero.