I don't think the DX7 has servo match - haven't come across it in the manual nor anywhere in the TX.

I'll look at the servo linkage some more.

During the downward part of the loop - I only have a slight up pressure on the elevator (less than a 1/8 input) and as I finish the loop I give it a tad bit more up elevator to level her off - thats when it tips - but i'm only giving it - maybe - quarter input. I checked the throws on the ground with the same (approximate) inputs and the differance is very minimal. I see the differance at the highest and lowest but not in the middle. Can that slight differance in the middle be enough to make the plane tip? obviously, something is going on and I will double check my linkages.

I have DS821's on all sufaces and the rudder is the HS-5625MG. Powering it with an OS FS91 surpass III w/ pump. spinning a 14x6 Master.

Yes you can match those elevator servos. Connect one to the elev. channel, and the other to AUX 2, (aux 1 is probably being used for the ailerons)...Now select one of the last 2 mix choices as they will allow both surfaces to respond to trim changes. Now you can adjust end points for each channel and use other functions to even the travel throught the range. I tape brass tubes to each elevator after adjusting them so they are about 1 foot behind the surfaces and pointing at each other. Now you can watch the action of each elevator throughout its entire travel range. Now adjust away. Please don't tear your hair out though. Getting them perfect is a lengthly process.

Billiefly- all good comments on the L/R balance stuff.
What I wrote about flat spinning kind of assumes pretty good L?R balance- but that isn't always a good assumption on my OWN planes, no less somebody else's!
NRAD2000:
Any chance your battery is flopping around during a loop? If the loop made it flop left to right, you could be seeing this effect as you level out the loop.
Anything reasonably heavy could do the same if it weren't held in place.
Another thing that I wanted to bring up because I did not catch it is whether you have the two servos both linked to the elevator on the top side of the horn:
http://www.rcuniverse.com/forum/fb.asp?m=9439191
The original kit suggests using a Y harness, which also requires the elevator linkages to be top and bottom, leaving significant asymmetry in the throws that you would fight.
With all DS821's and the OS 91, you are probably over 7.5 lbs. Heavier is snappier, but 7.5 shouldn't snap out as you slightly tighten a BIG loop.

I have (2) HS225 servos on the the elevator, with the linkages both on top side of the horn.
Mine is under 7 lbs and can loop around itself in maybe a 15-20 ftØ loop and not snap out.
If you are using the DX7, make sure you have the slave channel's ATV at 0% both directions. I say the slave channel, because some use CH5 (gear) others use CH7 (AUX2) but either works. You just want it (the slave) to follow the elevator channel, not add its own stuff as well. Maybe there is something happening there?
Remember to use one of the last two Mixes so that the trims come across from elevator channel, like Maynardrupp said. That's a peculiarity of the DX7.

One more thing:
My elevator counterbalance surfaces did not agree with the bulk of the elevator surface when viewed from the rear.
Many people I talked to use a couple of popsicle sticks to clamp the counterbalance surface (that part ahead of the hinges) fluch with the stab.
When I used that shortcut to set mine up, the elevator halves were way off just at neutral, adding some twist that the ailerons had to be set to counter.
So give a look from the back, at neutral and other positions to see if the two halves agree, ignoring the counterbalances. Those little counterbalances are probably less than 10% of each elevator's area, so if they are off you'd want to ignore them like I do. Its the bulk of the elevator surface that you need to set equal. The errors I'm talking about (measured at the counterbalances) are one shirt cardboard thickness up on one side, and two cardboard thicknesses down on the other, FYI. That's about 1/16" on one side, 1/8" on the other when the bulk of the elevators' surfaces are at neutral.

I used 2 mixing sticks and taped it to the elevator closest to the rudder. I got it to mix really close. it's down to a millimeter or so on both up and down. one other flying guy said " did you balance it side to side". Ah, no. He picked up the plane from the tip of the spinner and near the center of the back of the plane and the plane plopped to the right. same side that drops in the loop. he looked inside the plane and noticed everything is down mid line except for my throttle which is on the right. Since I have an OS FS91 mounted horizontally (rockers on the right) - he said maybe that is why the plane could be favoring to drop the right wing. he suggests to mount the battery on the left wall of the plane and what ever I can move to the left. I was thinking maybe put weights into the aluminum wing tubes on the left. what do you think about that?

My battery is well secured under the tank. I have the tank pushed far back - right infront of the wing tube. Nothing inside moves except for the servo connectors to the wings - they are slightly free hanging inside.

I flew thru the loop a little faster and noticed that right wing drop tendancy slightly went away. I maybe just exiting the loop too slow and stalling that heavy side.

Hey guys, it has been awhile since i blogged here. I just wanted to update everyone on my plane. I crashed it and brike the fuselodge into a lot of pieces The good news is that I like this plane so much I ordered a new fuselodge. Tonight, while installing the fuel tank I discovered that the fuselodge has been modified. On page 59 of this blog I talked about glide issues with this plane. I found that moving the fuel tank back @2-4 inches really helped this plane to glide better. See post @ top of page 59. Well, tonight while installing the fuel tank i discovered that the new fuselodge is designed to prevent the fuel tank from going all of the way forward. the fuel tank is @2 inches back from the firewall. Some thought I was crazy for doing this but, it really did improvr the glide. Now it seems that the manufacturer agrees with that. So if you have an earlier version of this plane and the plane feels nose heavy with a full load of fuel, and it balances well empty and upside down, then moving the fuel tank back 2 inches will really help. My old one glided like it was on rails after i slid the fuel tank back. It did not glide very good with the tank all the way forward. Thought that I would inform others who have problems with this plane. Setup right and balanced right it is a very good flier.

I had to modify the canopy to get the fuel tank back. But I agree, the plane glides nicely.

Mine was tip heavy on the side that the engine cylinder is on. I just slit the covering on the bottom, just inside the last rib at the tip. Now I glued the needed weight to the rib and put one of the supplied decals over the slit. Hanging the airplane to check lateral balance is a problem. I glued a strip of light ply across the fuselage at the CG. I drilled a hole for a 2-56 T nut exactly in the middle. On the outside I screw in a 2-56 eyescrew. Now you can hang the airplane upside down with a string through that eyebolt. Now you are checking both lateral and for and aft CG. I mount one of these little eyescrews in all my airplanes. You can unsrew it when you are done.

Not a bad idea! Think I'll give it a try.

Phoenix makes a Katana and Edge in the 1.20 size. I am asking Tower to special order them. They are getting me the prices. Any one in the states flies the Phoenix Edge, or Katana?

Nrad2000:
Glad you checked the L/R balance and found some low-hanging fruit.
A plane that is trimmed for level flight at mid-throttle speed can't correct an imbalance as the speed drops. So balanced is definitely where you want to start for good trimming.
If only I had a nickel for every article where a trimming wizard makes the point to do balancing and straightening before any trimming..... I could afford a spare Extra!
When it comes to balancing, I use three rules, in this order. Because lighter is pretty much always better!
(Exception is windy days of course!)
1. shift existing weight
2. remove weight from the heavy side... (rthis is rarely possible/practical so it gets demoted from number 1)
3. add weight only if all else fails, as far away from the CG as possible, so the minimum weight will do the job. You are applying a torque, so lever length is as good as weight, nay, better.

Your friend's advice to move the battery is excellent, and a good example of #1. A lighter or heavier battery is also an option in combination with position.
Your wing tube idea is good, but 1 oz at the end of the wing tube is like 1/6 oz (approx) out at the wing tip. Great way to save 5/6 oz is to put the weight "out there".
That "leverage" of a smaller weight further away from CG is why maynardrupp was slitting his covering to put weight in the last (outboard) rib.
Some fliers like to use those convenient stick-on lead weights, but I always glue weights in for permanence.
A short(ened) nail or screw or two, a penny or dime even a small wrench or other small bit of sheet metal often works well, right out there at the wing tip.
A row of little #2 or #4 wood/servo screws along the wing tip looks kinda BS scale!
Let 'em wonder why you glued a crappy broken off tailwheel to the wingtip...if they ask:
Answer: for botched landings, of course!!!! (I've done this on a funfly and gotten quite a few guffaws- but it worked!)

cmoulder- I agree that Maynardrupp's 2-56 eybolt for balancing "both ways" is a great way to go. I remember him mentioning that a year ago. I recently used his trick on a 1/3 scale Pitts (Byron) to do CG:
Two 4-40 bolts stuck out the bottom on centerline to hold the belly pan on and I put a piece of perforated steel plumber's strap between them and then "pick a hole" to hang it from with a binding screw. The 4" steel strap weight is negligible so close to CG and is a great place to pick up the 15 lb plane!

So thanks again, Maynard! Maybe I can catch up to you at Stoney Creek this summer.

So, it's safe to put weights on the wing tips? where on the wing tips? at the leading edge? smack in the middle?

As near the main spar as possible. Usually between the spar and trailing edge strip. Glue them with thicckened epoxy.

Maynard is spot on, but there is a little enhancement I would add. If you need tad more tailheaviness, go behind the spar. If its already a little too tailheavy, go ahead of the spar. Maynard's X'lent suggestion to go "near as possible" to the spar will maintain your current front/rear CG, assuming your CG is on the spar. In a pinch, put it wherever it fits well on the wingtip. You are probably working with such a small weight (<1oz) out there at the wingtip that an inch or two ahead/behind the spar will do very little to front/rear CG. Remember, the fuel weighs ~0.8 oz per fluid ounce of fuel, so a 12 oz tank has 9.6 oz of fuel at ~8" ahead of CG that comes and goes during your flights of glory. I'm guessing that whatever you put on the wingtip, whether ahead, on or behind the spar will do nothing to fore/aft CG compared to using a heavy APC prop vs a wood prop. That's because the props are at ~12" from the CG and have a lot more leverage than the little bit of wingtip weight you'll have to add.

ADVANCED CONCEPT (meaning you can ignore this and still be just fine..): you could shade your wingtip weight position forward/aft of spar to reduce/eliminate any weights previously added for fore/aft CG. For example, if you put the required weight for L/R CG (say its 1 oz for discussion purposes) 2" ahead of CG, you could eliminate 1/4 oz that you currently might have in the nose 8" ahead of CG. Again, its all about leverage, so 1 oz at 2" from CG is equivalent to 1/4 that weight 4x further out from the CG at 8" from CG. Its not magic, its just a bunch of see-saws! Remember how it took two normal kids to see saw against one heavy kid- or you could just have the heavy kid move toward the pivot and have one normal kid....
Hope that helps, sorry if I have offended any normal kids out there!

I was the normal kid - LOL.

That really helped. I'll peel back the covering on the wing tip and add the required weight to balance it side to side. Hope this will correct the problem.

OK,

I will be very shortly putting together the Extra myself. Mine is old stock meaning it doesnt have the 2" tank spacing from the firewall, I will do that myself.I also plan to use push rods instead of the pull pull rudder and will reinforce the tail and landing gear with additional formers and fiberglass cloth. Anything else?

Ameyam

use magnets for your canopy - I did - makes it easy to get in and out. also, make the firewall stronger.

For the canopy, I used a cabinet door latch from lowes. .89 cents. The kind with rollers and metal tang. I glued some square hard wood across the rear of the canopy opening inline with the canopy screw holes.. ( don't go all the way across unless you plan to remome the screw tabs from the canopy) leave room for the canopy tabs. i glued it to the plywood brace that goes across there. I did the same to the canopy, where i mounted the metal tang. Not sure how to upload my phots' of this to you. it won't let me browse for the photo. anyway this has worked well for me.

Hi, as i saw, there are people flying this plane with the descriptions, almost like mine. i have one with a ASP .91 4 stroke, with a 14oz tank. i have a CG problem, i mark it a 120mm from the wings leading edges, and i balanced the plane to be a littlenose heavy. When i took it to the air it declares a tail heavy, but in my CG machine was balanced, so i flew it with difficulty and land it in a grass field, separating the main landing gear base from the fuselage. I reinforced the base and glued it again in position. Going back to the CG subject i took this time the rule of the 25% front limit and the 33% rear limit areas for cg, from the leading edge of the wing in the part that is next to the fuselage, the 120mm cg point that the manual says is almost next to the 33%( rear part) instead of being in beetwen the 25% and the 33%.

Can someone tell me how can i make a good CG balance in this plane ?

At first with no RX battery my plane balanced tail heavy. Too heavy. I placed my 3s 1050mAh Lipo right under the fuel tank. Oh, my fuel tank is pulled back right infront of the wing tubes. I have an aluminum spinner on the nose, remote glow driver right below the cowl, and extra epoxy and hard wood supporting the firewall from the inside and beefed up the wood around the landing gear area. Balances now exactly at 120mm.

But will a 75AX with a 14x4 prop be sufficient for 3D-sports hybrid on this airplane? I have almost given up trying to fix the landing gear on my Reactor 46 and wont have a ready 2c airplane if the repair doesnt work out

Ameyam

Hi, thanks for share your opinion with me, I'll try moving the rx battery to the space beetwen the fuel tank and the servo tray, let's wait what i found during this process.
Can you tell me how you get access to the back of the firewall, i want to do the same as you didN but i don't want to cut the cover film or wood. Is there any way that you show me photos of all the improvements that you make to this plane?.

Best Regards.

it's not improvement - it's just re-enforcing. You don't have to but I do. I have just heard stories of firewall breaking off and that alone was enough to scare me. Basically, I placed the nose facing down and dribbled epoxy glue down into the corners of the firewall. that alone probably does a lot. But, I also took a small piece of angled wood and dropped it down into that corner. Use a long wire to move it around and to press it down. I used the side holes to get to it. Right below the original fuel tank would be is the landing gear mounting block. It just feels thin. I basically epoxied the whole bottom ( try very hard not to get into the blind nuts) and laid a few pieces of wood behind it (goes from one side to the other). Hard to explain. Also, the wing bolts mount into the walls - I placed a round dollar size plywood and epoxied that to the hole so that when the bolt goes in it has something more solid to rest up against (the dollar size plywood also has the same size hole in it). On the canopy I cut out the Grey bottom where the pilot dude sits on. That really lightened the canopy. I put a cross beam on the canopy and mounted a 1/5 scale Great Planes Pilot. Looks much better. My plane is Right Heavy - due to the OS FS91SII cyclinder. I haven't done it yet but with everyones help and idea's on this forum I have decided to put some weights on the tip of the Left wing. For some reason at the bottom of the loop the Right wing drops every time. I can anticipate it and correct it with stick control but it's beginning to bug me. Oh, also I built a bridge that goes from the original fuel tank area to the front of the wing tube. my fuel tank rests on that bridge. because the tank comes back it made it near impossible to put the front wing bolts in. I now use a dubro black nylon wing bolts and cut short for the front. I use just the socket from a socket wrench set to turn the wing bolt - cuz you can't get a tool in there (especially when there is a fuel tank in-between). I also used rare earth magnets (8 pieces) on the back of the canopy to secure it. no bolts - I just have to pry it open with my nails to get it to open. those magnets are strong. there 1/8 in. thick and the diameter is about the same size as a #2 pencil eraser. I'll try to post a picture or two - sometimes this week. tooo tired right now.

Seeing as some are flying it with a FS91SII, I assume, it will definately fly with a 75AX. What I want to know is, will it 3D with that engine with some authority in the hover? I dont want it to rocket out but the pullout should be sufficient to get out of trouble. A fellow flier has the Phoenix Yak 60" which is essentially the same airplane without the radial cowl. But he is using a 120AX on it. I have a 120AX, but the original idea was to use this airplane as a test bed for the 75AX (which had given me problems earlier) so I want to stick with the 75AX and have fun with it

Ameyam

Back on page 64-post # 1585
Some nightmair stories followed but
i wrote:

After pulling the Hacker motor and all the components out of
my Phoenix Extra 330 .61-.91
i had to patch all the air holes and the hole i made so the electric
motor would fit.
Even though it cost me 1/2 oz in glass and epoxy; I'm Real glad i did !!
There are two tabs on the very front of the firewall that secure the side
of the fuce to the fire-wall and also double as a attachment point for the
cowl.Can see good in link below:
http://www3.towerhobbies.com/cgi-bin...LXNCT4&amp;P=Z

I cut them off so as to wrap glass and epoxy to strengthen the fire-wall.
-There was hardly any glue in the hidden joint-
,and i'm betting that the
DLE-20 would have pulled the mount right off the front of the plane !!!
2 hr of work and glass later-It's not going anywhere now. But if you
have this airplane,be SURE to check this before mounting a DLE-20 to it !!
Bille <span class="info"> </span>

OK, i'm going to try to do the same that you did, and i hope everything goes ok. In the meanwhile i uploaded the video on youtube.
http://www.youtube.com/watch?v=R_UHTcDa5JI
I accept comments and suggestions.