RE: New Giant GP Super Sportster!!!!!
 

I have long since stopped flying IMAC competitively, but I still like to put my 50 cc Edge through the paces just to keep my diminishing reflexes sharp (just turned 70). So I will reply from that perspective.

One of the things that I learned back in the day was you had to have the aircraft properly trimmed out in order to fly the maneuvers. We didn't have these computer thingies. With that having been said, knife edge pitch is primarily a function of CG. Ailerons have nothing to do with it. If the plane pitches toward the canopy, move the CG aft. If the plane pitches toward the belly, move the CG forward. This has always worked well for me, provided that the aircraft is designed for these types of maneuvers.

Also, when doing KE in a cross wind you have to learn how to simultaneously use your elevators the same way you use your rudder in level flight. If not, you will lose points for not maintaining a straight line of flight.

Like Al said, nothing written in stone and so much has to do with the design and construction of the aircraft in question.

Al

RE: New Giant GP Super Sportster!!!!!
 

If you try to mix out any KE coupling - without trimming the CG for a neutral elevator first - you are going to be using enough mixing where you are darn sure going to notice that mixing in level flight. You'll want it on a switch for sure!

RE: New Giant GP Super Sportster!!!!!
 

I agree with the CG statement %100, best way is do a 45 degree inverted climb out and see if the tail drops and tries to go vertical. My ships are neutral at that attitude. Elevator neutral, of course. You should not require down elevator when inverted either - My airframe is so close that my mixes are on all the time. They are not sport planes - and the mixes are minimal but perfectly "tweaked".
I remember some first attempts at knife edge with a slightly nose heavy 4 Star and the belly tuck coupled with weak rudder were a big lesson in knife edge flying. Very difficult to control.

One of my friends flies a clipped wing cub and he can knife edge it across the sky, talk about degree of difficulty :-) He has to use massive rudder and constant correction, nothing that could or should ever be attempted with mixes!

Paul

RE: New Giant GP Super Sportster!!!!!
 

Great advice guys. I moved the CGback on my GSSwhen Iadded the pushrods and now it barely has a click or 2 of up trim. When Iput the pulse back together I decided to run the CG at the most rear point recommended by the manufacturer. Turns out that I had all the same weights on it as the first time when it was nose heavy. There was a lot of repair aft of the wings (it snapped in half just behind the canopy) so the extra material added just the weight that I needed. Now that plane also only has about one click of up trim. It still needs more down elevator flying inverted then the GSSbut Ibelieve the semi symmetrical wing of the pulse has something to do with that. I really appreciate the answers and feel confident that what Iwant to try will work. Someone mentioned that Rudder to elevator mix is not required for KE flight. From what I have been reading you should always use a mixon the ailerons to get the roll coupling out of the plane and that should be on 100% of the time in all flight conditions. Do you all agree?

RE: New Giant GP Super Sportster!!!!!
 

"Rudder to elevator mix is not required for KE flight" - OOPS! I meant to say rudder to Aileron

RE: New Giant GP Super Sportster!!!!!
 

Describe "roll coupling" please?

RE: New Giant GP Super Sportster!!!!!
 

I have always understood roll coupling to mean that when you apply rudder you not only get yaw but also get a roll ineither the same direction as Rudder input or sometimes oppositte. I have a pattern type of plane that has almost zero roll coupling but Inoticed with my pulse that when you are hard rudder it wants to roll in the direction of rudder input. My GSSdoes the same thing. If I hold it in straight level flight and apply rudder it will start to roll in the direction of the turn.

RE: New Giant GP Super Sportster!!!!!
 

I have a slight roll when knife edge right to left (counter clockwise), removed with a tiny amount of rudder to aileron mix. There does not seem to be the same amount flying clockwise knife edge. Again, I use the mixes all the time. After CG and neutral elevator tests, I do a very long KE pass in each direction to test for the roll. In the counter clockwise direction I had to mix a bit of aileron to compensate - not sure what causes it on an aerobatic airframe - maybe the 2 and 1/2 degree right engine offset? The airframe also does a KE with a bit less rudder when flying it right to left. When all balanced, I can circle the field in KE without a problem in either direction. The mixing is so minor that I cannot detect it without hard rudder deflection, so it just does not come into play much in normal flight.

The roll coupling occurs more strongly if the wing pattern has the slightest dihedral or difference between the wings - witness how the rudder/elevator/throttle 3 channel trainers work. They bank just as if there were ailerons on them.

RE: New Giant GP Super Sportster!!!!!
 

OK, gotcha. I've never taken a plane to that level, where I'm trying to mix something like that out? -Al

RE: New Giant GP Super Sportster!!!!!
 

Good stuff guys. I am going to try some mixes this weekend and will post results.

RE: New Giant GP Super Sportster!!!!!
 

I was thinking about the roll coupling - what might cause it? Would it not be caused by a larger percentage of the rudder area on one side of the plane's roll axis? That vs. a plane where the roll axis splits the rudder area in half?

RE: New Giant GP Super Sportster!!!!!
 

From Masportaviator:
<span class="goog_qs-tidbit goog_qs-tidbit-0">In almost all sport model aircraft, applying rudder alone can cause the aircraft to bank into a turn without aileron input. The ability of the rudder to</span> perform a banked turn is called roll coupling since the rudder input also induces the roll into the bank. Roll coupling is caused by wing dihedral, (the upward bend in the wing), and rudder placement. The higher the rudder is above the wing and fuselage, the greater its roll coupling effect

RE: New Giant GP Super Sportster!!!!!
 

Muttdog, what you are referring to is called adverse yaw/roll. If the center of pressure on the rudder is lowered, the model will begin to roll in the input's direction. This is called proverse yaw/roll. It's early and I haven't finished my first cup of coffee yet, so bear with me if I've got it backwards. I'm sure someone will jump in there and straighten me out. <G>


Ed Cregger

RE: New Giant GP Super Sportster!!!!!
 

Sheesh, umm, I kind of forgot this is the GSS thread - the minimal mixes I use are on an aerobatic airframe that is already very close to neutral - not sure the GSS will behave well since it has dihedral and the rudder position is not really designed for aerobatics. Most of the aerobatic airframe world has the wing in the middle of the fuse aligned with the H stab and the largest area of rudder is on the bottom. That reflects all the stuff posted about minimizing roll coupling. It really may need a great deal of experimentation and a switch. The 30cc Syssa I was planning for a GSS is now residing in a 25% Pilot RC Extra -

Paul

RE: New Giant GP Super Sportster!!!!!
 

Paul:
Yeah I think we may be starting to get a little off topic. I am glad for the responses though and will use the info learned here this weekend. Didn't intend to derail anything but hopefully we all learned something - I know I did.

RE: New Giant GP Super Sportster!!!!!
 

Paul, the fact the Syssa is currently "occupied" doesn't sound like a very good excuse to me. Just would be a pretty good reason to get another one - or maybe a DLE35? :D

SOPM....

(spending other people's money)

-Al

RE: New Giant GP Super Sportster!!!!!
 

Yup,
I fly a lot of aerobatics, but I know I will have a GSS because an evil person at the field lets me exercise his on occasion :-) Sure is a sweet flyer in all types of conditions -
Not sure of what motor yet, but maybe even electric.

RE: New Giant GP Super Sportster!!!!!
 

Hmm,
Wonder who that evil person is? We'll be trying out the old US 41 on it this Spring. Hope it is not too heavy for it.

RE: New Giant GP Super Sportster!!!!!
 

That's the engine mine had in it for it's first season (Q42) - was my first gasser! Taught me a bunch, obviously hooked me on gas, and it flew pretty good! At 16.5 lbs. or so though it was not a light weight, but still had pretty good vertical. I used an APC 20" prop, but don't remember if it was a 6" or an 8w? Much trimmer now at something closer to 14 lbs with the Syssa.... biggest differences are in it's slow flight envelope.

RE: New Giant GP Super Sportster!!!!!
 

Hi Dave,
I thought you might be enticed to say something at this point - ok, evil in the way that "way bad" is great!

ahicks - 16.5 lbs, wow - that is a wind penetrating beast at that weight. My 50cc Sbach comes in at 15lbs and 15 ounces on a dry day. It will be quite a different feeling switching between the two eh?

Paul

RE: New Giant GP Super Sportster!!!!!
 

When did this "new and improved" Giant Super Sportster" hit the market? I have a feeling that I am way behind times.

Ed Cregger

RE: New Giant GP Super Sportster!!!!!
 

Boy this is the longest I have seen this thread dormant. I thought I may have been unsubscribed again but I see No one has been posting. After having so much fun with the newly repaired pulse over the last 3 weeks I decided to fly the GSSagain. I had a great flight but it was with a heavy heart and to be honest I was quite distracted. I wanted to share this with everyone just in case it can help someone. There is an older couple at the field where I fly. The gentleman is a great flier and he and his wife both accepted be into their group immediately. I have learned so much from them and even though they are 30 years my senior, we have become friends and I really look forward to seeing them every Sunday. This weekend they were not there and I was horrified to hear why. It turns out that My friend was charging a LiPo battery in his garage unattended. His wife heard a pop and notified him. By the time he got to it, the Garage was up in flames. Long story short, it was a total loss. The House, everything inside, and a car in the driveway are all totally destroyed and he got injured trying to deal with it. All from a stupid battery for a "toy". On top of that they owned their home and had no insurance. It just made me sick to hear it and flying didn't seem so important anymore. I don't have anything that takes LiPo batteries but if/when I do I will be doing what one guy taught me. He charges them outside inside of a ceramic pot. I thought he was a little odd before but now that I have seen first hand what can happenandI will exercise a lot more caution. I beg eveyone using LiPo batts that they exercise EXTREME caution. If your charger has a temp sensor option USEIT but no matter what charge the battery in a place that it will not ruin your life it fails. I heard the warnings before but it's different when someone close to you experiences something like this. A couple in their seventies should be enjoying retirement, not moving in with their kids because they lost evertyhing they own. Sorry I went off topic here and I will climb off the soapbox now. GSSflew great and my goal now is to learn the basic Imac routine so Ican hopefully enter my first contest in April.

RE: New Giant GP Super Sportster!!!!!
 

Very sorry to hear of this event. Do you know if the charge connection was through the battery mains or through the individual cell connector? I use quite a few Lithium Polymer batteries for my electrics, but only charge through the individual cell wires. That limits current input and the charger also "knows" the cell count do to the wiring in the connector. I use a CellPro 10s for the bigger batteries, it has been very safe and stable. I think large electrics will be growing in popularity, especially where there is good space to fly but objections to noise.

I admit that my smaller batteries are not kept in a fire proof box, but all the bigger stuff I have, say 2600mah 4 cells or higher are stored in a fireproof container. I charge on a concrete floor, or outdoors for the big batteries. Small Lipos for indoor flying we charge at the event on the table, but those are under constant observation.

Anyone electrify the GSS?

RE: New Giant GP Super Sportster!!!!!
 

Isn't Boeing having trouble now with the 787 and it's Li ion batteries?

RE: New Giant GP Super Sportster!!!!!
 

The Dreamliner has a big problem with them. Grounded until they find out why they are burning up - maybe Boeing should get in touch with Tesla?
The people with the best Lithium tech are the Tesla designers - even Toyota bought into that design. The model S can run for 300 miles and the tech has been solid.