I had a hard time trimming my plane. It'd either stall immediately and nose or fly run out if gas and nose. I couldn't get a nice flat glide. I felt like I was tossing it too hard and so it'd stall and dive while lesser power stalled it as well. I don't want to keep smashing it into the ground.

power : haven't gotten that far but I have a stock motor from great planes - hellfire or goldfire something. Runs like mad on the test bench but its battery is an 1800 mAH NiMH 7.2v. I think even prior to lipoly GreT Planes has been selling the 500' per minute for this craft - is this realistic or were they lying? The manual specified no new or more things to purchase to achieve this. At anyrate any help I can get balancing and trimming for max glide is appreciated.


Pete<br type="_moz" />

The safest way I found to trim a new glider before it's first flight was to test glide them. The test glide takes a slight effort and just a touch of skill.

Jog into the wind holding the glider just over your head. Hold it at the CG and feel what it's trying to do. If you can't feel it, then jog a bit faster. You need some room to do the test of course, about as much room as you'd need to safely land from altitude. It usually takes me about 2 or 3 easy jogs to warm up the old legs and see if the glider is trying to nose up or to nose down. The last run or 2 is a bit faster than a jog. The last run is the trick. Push up a bit and let go. Keep your hand close and just let go for a second. See what the glider wants to do and trim for it.

Then go back to your start line and jog it up to however fast you get in 4 or 5 strides. A human walks at about 3mph. He jogs a bit faster. Gliders have no trouble flying at jogging speed. It's a perfectly safe way to see how they're trimmed for landing. It sets the glider up for a safe hi-start launch or powered launch.

If your CG is bad, you will discover that with the glider inches from your hand. If you've set the CG by the plans, and trimmed the elevator jogging, the first jog and complete release will probably show your test field is too small. I no longer try that test at soft ball diamonds. They aren't usually big enough. When you get to the point you're pretty sure of the trim and let go to see for sure, I've never needed more than a click or two of elevator trim. The only risk has been when trying to use too small a field.

If you've got a place large enough to fly from that has room to land (without having to snatch 'em out of the air), you'll have room enough to get the glider trimmed close enough just jogging. If it's big enough to jog and release, you'll be able to get the trim spot on.

<div dir="ltr" style="font-family: ; color: ">&gt; Video of a Hand Throw Test Glide - Best done over tall grass.</div><div dir="ltr" style="font-family: ; color: ">&gt; <font color="#0066cc">http://www.youtube.com/watch?v=ixwur8lakBM&amp;feature=related</font>

So let me ask all the dumb questions.

This is the Carl Goldberg Spectra,a wood 2 meter glider with a motor in the nose?

Do you have the CG set as per the instructions?

Is the elevator flat to the stab in neutral position?

Are the vertical and horizontal stab tight with minimal flex?

Have you checked for flex in the push rods? If you hold the elevator togive <u>some</u> resistance and move the stick, does the push rod bend or does the elevator try to move against your hand? Same for rudder.

Is there play in the surfaces?

Did you build this from a kit?



These are not relevant to trimming but just general info

What motor are you using?

What battery?

What radio/receiver?

Can you provide photos of the glider and component installation?

</div>

I want to thank you guys for the help and apologize for the long delay as I was out of Internet access.<div>The particulars on the set up is this...</div><div>
</div><div>1. Kit built spectra</div><div>2. Batteries are 1800mha not lipoly.</div><div>3. Really nice radio. Four channel Futaba has over a mile range .</div><div>4. Groppner folding prop, soft start</div><div>5. Original Goldfire motor, broken in .</div><div>
</div><div>Hope this helps!</div><div>
</div><div>Pete</div>

OK, let's get to tuning.  Note that this was written ro a pure glider to be launched from a hi-start or a winch.  So, right up to the discussion about the tow hook this still applies to you.

<div>PREFLIGHT AND TEST FLIGHT PROCEDURES FOR GLIDERS</div><div>by Ed Anderson</div><div>aeajr on the forums</div><div> </div><div>Here are some quick tips and a "check sheet" for preparing your glider for</div><div>launch.  If you are a new pilot, you really need to heed the wind cautions.</div><div>If you are experienced, use your own judgment.</div><div> </div><div>Here is how you prepare for your first flights.  Skip a step and you open</div><div>yourself to problems.</div><div> </div><div>Be sure to balance the plane to the suggested point.  If you don't have a</div><div>reference setting from planes or a guide, then try balancing on the main</div><div>spar as a starting point.  Another reference point is 35% back from the </div><div>front of</div><div>the wing at the root.  It is more complex than that, but it will give you a</div><div>starting point.</div><div> </div><div>Gordy's Balancing System</div><div>http://www.flyesl.org/forums/topic.asp?TOPIC_ID=255</div><div> </div><div>It is better to be a "little" nose heavy than tail heavy on your first test</div><div>flight.  A nose heavy plane is more stable so you have a better chance of</div><div>a smooth first flight session.  But stable is not your goal, it is proper </div><div>balance.
</div><div>
However, as you gain experience with the plane, plan to move the CG back.</div><div>This is a process you want to do slowly.  The plane will be more sensitive</div><div>to lift with a more rearward CG, BUT, it will also be less stable.  You have</div><div>to find that happy point and there is no magic formula.  What works for you</div><div>is what works.</div><div> </div><div>Respect the wind - For new pilots, dead calm to 2 MPH is perfect.  No more</div><div>than 5 MPH for your first test glides and early/training flights or you will</div><div>be fighting the wind, not flying the plane.</div><div>(guess how I know)</div><div> </div><div>AT THE FIELD</div><div> </div><div>1)  If you are flying 72 MHz, make sure no one is on your channel BEFORE</div><div>you turn on your radio.  Remember 72 MHz needs frequency control.</div><div> </div><div>2) Do a range check before the first launch of the day or after a hard</div><div>landing.</div><div> </div><div>3) Make sure that battery is fully charged just before the launch.  Not 3</div><div>days ago.  Not last week.  Last night or today!  And make sure it can't move!</div><div> </div><div>4) Make sure all your surfaces are properly aligned and move properly before</div><div>you launch.  Right rudder goes right and up elevator goes up, etc.  Check</div><div>that surfaces are properly aligned.  Also make sure your wing is straight!</div><div> </div><div>5) CHECK THE TRIMS!  Check the trim slides on the side and below the</div><div>stick(s).</div><div>Be sure you have not bumped one out of position.  A bumped trim can cause</div><div>the plane to crash.  (guess how I know).</div><div> </div><div>6) Always launch and land into the wind.  ALWAYS!!!!</div><div> </div><div>7) For hand launches - good firm LEVEL throw - not up.  Never</div><div>throw the plane upward on a test glide as it will most likely stall, nose</div><div>down and crash.</div><div> </div><div>Video of a hand launch test flight</div><div>http://www.youtube.com/watch?v=ixwur8lakBM&amp;feature=related</div><div> </div><div>8) Let it fly straight out (no power on e-gliders also) - the fist few times</div><div>and see if it goes straight and level.  Try not to use the controls unless</div><div>you have to.  If it is balanced correctly, and your surfaces are trimmed it</div><div>should glide straight and flat for about 75 to 150+ feet.  If it does not,</div><div>you have some balancing or trim to adjust.</div><div> </div><div>The first time I bring a plane to the field I might do 10-15 test glides,</div><div>evaluating and adjusting then testing again.  Only when I am happy that the</div><div>plane glides straight and flat will I launch it.  If it is going to miss</div><div>behave I want to see it at 4 feet not 40 or 400.</div><div> </div><div> </div><div>IF THIS IS YOUR FIRST FLIGHT AND YOU ARE LEARNING ON YOUR OWN</div><div> </div><div>If you are learning to use a hi-start on your own, consult this article on</div><div>learning to use a hi-start:</div><div>http://forums.flyesl.com/topic.asp?TOPIC_ID=216</div><div> </div><div>My suggestion is to make your first few hi-start launches purely test and</div><div>trim</div><div>launches  Launch and spend your time testing the behavior of the plane.</div><div>Avoid</div><div>thermals until you are sure of your plane.  Land after a short time and see</div><div>how it lands.  Do several launch and land drills to get to know the plane.</div><div> </div><div>If you have a standard radio, or a radio with mechanical trims, you should</div><div>try to trim the plane so that your trim slides will be centered when you</div><div>fly.  It makes it easier to have the radio right before you fly.  If you</div><div>have a computer radio with digital trim buttons, this is still a best</div><div>practice, but less of an issue as the radio will set your trims where you</div><div>last saved them.</div><div> </div><div>If you can locate some tall grass to do your first glides, that is a real</div><div>bonus.  Naturally your plane will fly perfectly the first time you glide it,</div><div>but if something is out of trim, the tall grass will help cushion the plane</div><div>if it hits hard.  I always go to the tall grass to do first glides of a new</div><div>plane, or a newly repaired plane</div><div> </div><div> </div><div>Full Launch</div><div> </div><div>After this, I go for a full launch, but I am not done yet.</div><div> </div><div>Now I test how the plane lands.  This is more of training for me.  So I</div><div>launch, fly two circuits around the field, then land.  I may do this 10-15</div><div>times until I can land the plane, reasonably reliably where I want it to</div><div>land.</div><div> </div><div>If I have a landing mix set-up, here is where I test it.  I test the landing</div><div>mix at 100 feet to see what the plane will do.  If it stalls or dives, I</div><div>will have time to correct.  If I do this at 10 feet the first time, I may</div><div>not recover in time to save the plane.   Only when I have tuned the landing</div><div>mix will I use it near the ground.</div><div> </div><div>I worry less about where I am going to land than that I can make a safe</div><div>landing.  There is no walk of shame while testing.  Protect the plane, not</div><div>your ego.</div><div> </div><div>Once I have done all these things, which might take hours, then and only</div><div>then would I go for a full flight.  Many will say this is over kill.  I am</div><div>only</div><div>sharing what I do.  I feel it is better to spend the time to tune and learn</div><div>than to risk the plane or the repair bench.  I want to know the plane is</div><div>right</div><div>before I send it out hunting.</div><div> </div><div>Clear Skies and Safe Flying!</div><div> </div><div>OTHER RESOURCES</div><div> </div><div>Welcome to the Novice Lounge</div><div>http://forums.flyesl.com/topic.asp?TOPIC_ID=224</div><div> </div><div>CG Location by Mark Drela</div><div>http://polecataero.com/articles/cg-location</div><div> </div><div>Performance Tuning for Gliders</div><div>http://www.radiocarbonart.com/Pages/perftunemain.html</div><div>This is a fantastic video that everyone should get!  It is from Radio Carbon</div><div>Art, a company that makes RC Soaring videos.  I have several of</div><div>them and they are all excellent.</div>

You've been most generous and I've copied your instructions.<div>
</div><div>The problem isn't with my Spectra per se - indeed Im doing my best to spare it the fate of the Odyssey. It was my first and only attempt at balancing an airplane. May I share my horror?</div><div>
</div><div>My Futaba is a fine thing. Just under $400 about 6 years ago. Its sat idol since "the horror". The Odyssey is a cheap constant chord wing junky thing. You don't have to have any appreciable experience to realize its junk and it was reflected in the price.  Nevertheless I took it to a park realizing it'll be a simple matter - just toss it and see what needs trimming. Oh and if its having trouble - well just pour on the power!!!! I was extremely impressed with the howling wind it created on my test-bench dining room table. Infact it was scarey powerful. </div><div>
</div><div>What a relative term.</div><div>
</div><div>So I put my thumbs under the wing roughly where the spar is - yeaaahhhhh - that'll do.  Afterall if its off Ill just elevator my way out of the mess one way or another! </div><div>
</div><div>Right?</div><div>
</div><div>I test all my control surfaces - the rudder and elevator whir with response . This is going to be good.</div><div>
</div><div>
</div><div>With that I level the elevator out and toss it...</div><div>
</div><div>
</div><div>I gave it a healthy throw and it soared up a few feet the came crashing down.</div><div>
</div><div>Huh?</div><div>
</div><div>Ok ok a little down elevator thee wings obviously have a lot of lift!</div><div>
</div><div>Crash. Ok it went a but and again nosed in.</div><div>
</div><div>Oh to hell with this. Ill power through it...</div><div>
</div><div>I had it at full throttle whereby it was tossed and made a nice angled line straight into the ground. There was no pulling out of it. </div><div>Elevators didn't do anything.</div><div>
</div><div>Ok Ill toss it up a little more maybe it needs a little angle help on launch.</div><div>
</div><div>It popped up and peaked about ten feet away then went straight down again.</div><div>
</div><div>
</div><div>At this point Im wishing two things...</div><div>
</div><div>1. I had wheels for a rolling take off and to hell with tossing it.</div><div>2. I shoulda got an RC sailboat and screw flight.</div><div>
</div><div>I tried a few more times but I realized I hadn't a clue as to what was wrong and power and elevators were no save wharsoever. I ended up breaking my motor mount and folding propeller. </div><div>
</div><div>
</div><div>I bought a new prop a month later after the disappointment wire off. This time I thought I had it balanced in my kitchen. Someone told me your finger tips at the right point will let you know if its balanced. It looked fine to me.</div><div>
</div><div>I went to the park again with the same results though this time I folded the enterprise in half and shoved it in the local garbage can at the park and swore off the endeavor. </div><div>
</div><div>
</div><div>To this day I have no idea if it was nose heavy or tail heavy. No clue. It'd either shoot up and stall then auger in or do a powered flight line into the ground 30 feet away despite up elevator and full power. </div><div>Because of my brute ignorance the Spectra I built from a kit has sat idly on a shelf. I can't throw 80hours of work into the local garbage and with nary a clue as to what the heck was happening.</div><div>
</div><div>I still don't get it. If its tail heavy it'll pop fly and stall every time. But under power it drills a hole into the ground in a straight line  30 feet away. It can't be tail heavy and not climb. But if its nose heavy how could it pop up and then crash sometimes? I'd feel better if I could say the battery was shifting but it wasn't the case.</div><div>
</div><div>
</div><div>So here I am my Spectra afraid of me and me afraid of it. </div><div>
</div><div>So there you go - my horror. Fueled with arrogance and naïveté . </div><div>
</div><div>
</div><div>
</div><div>Pete</div>

Sounds like the elevator was reversed.

Personally INEVER launch electric sailplanes under high power except in contest situations. It should be able to fly from a hand throw or with 1/2 or less throttle so I can observe it flying before I give it the guns.

As you can see my self invented notions of Rc flight were problematic at best. Ill follow your instructions systematically.


Pete<br type="_moz" />