Cougar429

My Feedback: (3)

Great to hear and congrats. What powerplant do you have on yours?

I'm hoping if we can get to the field to bring mine with me tomorrow. Have been setting it up on the new Tx.

Kind of a downward spiral here. Grass keeps growing and retaining more and more of what seems a constant rainfall. Won't dry up enough to allow us to cut between monsoons.

Air Sally

I have a turngy G-160 on 8s

Air Sally

These are very pitch sensitive so the only change we made after the madien!was to tone down the elev.

Cougar429

My Feedback: (3)

Tell me about it. I finally cut a swath wide enough in the 2' tall grass to attempt a take off this afternoon and flight #4 got VERY interesting. Plane was all over the sky till I got some trim in. Then it was just a case of light on the sticks or it "Diverged" again. Landing went fine until touch down, then it did a goat in the deep grass, (even angled forward a bit that tall gear does not help there). If I had the length would like to see how it works on pavement.

I had switched From Futaba to JR on this one recently and the programming was off, to say the least. I had tried to mix aileron and elevator dual rates to a single 3-way switch and for some reason moving it from center also had up elevator. Going to take a bit of work to get used to how they do things. For now, went back to the stock dual switch setup, although I don't like altering what I have on all the other craft, nor the fact one D/R is above the right stick. Definitely toned down both the elevator and aileron travel and added even more expo.

For the first time I got the chance to try the Eflight retracts. Work great, but the tailwheel hanging conspicuously out in the breeze does detract from the looks a bit.

Oh, yeah. Goes like stink with that Graupner prop. Took some picks with the tablet just before packing up and will try and get them uploaded tomorrow.

Air Sally

Good news Cougar ...glad you got it under control . I set the C/G just in front of the panel line . only have about 1/8" elev . on low rate .we started with 35% expo . seems to fly just like the navy version we had .I have pretty long gear on mine ...they are as long as I could make them . I do have them shimmed forward ,but the only time we see it tip forward is when power is applied too fast ,or when doing a touch and go with the flaps still fully deployed. the mods I did to the stab are working well ,and im glade I put the flaps on too ,a lot of work but she lands very sweet with just a touch of power on ...lands on the mains and rolls for a while before the tail drops down. The guys at the field were very impressed with how it flew and it's good looks. shame TT did not see to it that these planes were made a bit better they looked awesome and were nice kits . they just needed to mod the stab servo to the tail wheel area and put some glue into the build. I sure wish I could get a hold of the molds for this plane.

Cougar429

My Feedback: (3)

I have mine balanced right on the money, although for this flight I did have the cowl removed. Wanted to check the needles to compare to the 125 in the Waco as it seems to burn twice as much fuel. As it turned out I did have to tweak both LS and HS to get it running reliably. Since it's been over a year not surprised some adjustment was required.

Even on grass have to hold full up when applying power or it tends to lift the tail enough to lose steering.

I really should have looked at flaps when I had the wing apart, but was more concerned with repairing the damage when the wing tube tore loose. Are yours full or split and do you find the need to mix any trim when deployed?

Here are the pics just before pulling the wings. Have to also admit the plane was back in the van as the first assembly had me lose the retainer for the LH wing in the grass. Looked for almost 30 minutes and only plus was my friend I taught to fly has better eyes. Spotted the SOB right away!

Air Sally

I did full flaps ,there are pics in the RCG glow to electric conversion thread ,there is a tad of pitch up if you don't get slow enough before going to full flaps. so we drop the gear going by us ,turn 180 and go half flaps and drop full flaps as we turn base ,then just let it hang on the flaps coming down hill to final ..once on final we add power and adj alt with the throttle ,not much of a flair is needed and we just wheel it onto the runway ....im sure grass will require a lot of elev to keep it from flipping over. I modded my wings with a thumb screw to hold the wings on as I did not like the wood screw stock design . there a bit hard to get at but doable . where is your elevator. servo located?

Cougar429

My Feedback: (3)

I built a deck bonded between the two stab tubes and mounted a high-torque JR digital. Metal arm with ball links bolted to each side and running to each elevator. Solid as can be so no threat of flutter.

Only problem is one I also ran into with the Northstar; any weight here requires 3X as much in the short nose moment to balance.

I posted pics much earlier of how I modded the tailwheel steering to move the arm to the top and inside the shell. Has the advantage of running the springs to the rudder post perpendicular while hiding everything from view. Unfortunately you can't really see the servo and links hidden behind the tailweel mount.

Air Sally

I basically did the same thing . mounted the servo between the CST 3/8" C/F tubes I bought to replace the weak stock " straws"

Cougar429

My Feedback: (3)

Starting to regret the decision to try a different radio brand. Brought the Bear to the field yesterday and had a bit of a problem again. Once off the ground it headed orbital and even with full down trim I had to fly it with active down stick. This made fine control problematic and consequently I dropped it into the cut grass on landing rather than a bit further along. Broke off one gear and the trunnion on the other. Both are repairable with replacement parts and the gear mounts seem fine. Will need a closer examination once unloaded, (will have a boo though everything AGAIN! Starting to have the maintenance requirements of a Sea King helicopter).

Somehow, when rearranging the D/R setup again there was a whack of up elevator subtrim introduced. I was NEVER in that page at all!

Even though I have experience with lots of different radio systems from instructing, I have been flying Futaba for 3 decades and am comfortable with their programming arrangement and switch layout. Along comes a 10X touch-screen since it had servo speed option, (saved another module in the plane) but their flap programming had me pulling out my hair. Even my friend that flew turbines with this Tx was stumped. Anyway, recently traded it for a 9303 module to be able to use 72 and 2.4. Still a bit confusing, but at least I was able to get the programming to work much better. Biggest difference was I have D/R set up on the Futaba identical throughout the fleet, while JR has those split up all over the Tx and not really able to move them where they can work that way.

Another negative is the loss of shut down capability. With Futaba I can set the low speed idle position and leave it there, using the spring-loaded training switch to close the throttle completely and shutting the engines down when intended. With JR I have to use throttle trim, meaning while flying I am taking a guess at position for landing and then hoping I have enough range to drop it out. Would be nice to use the button on the upper right rear, but if that is available have not found it yet.


On a final note: flight test pretty much confirms a suspicion I had when the box was first opened. The elevators are far too large for this plane. Unless throw cut down and lots of expo you can practically swap ends. On a plane this pitch sensitive and having such short moments things get extremely interesting, to say the least. Add in the stock control linkage and iffy tubes easy to see why there could be enough flutter to tear off the stabs.

Air Sally

Yeah I've been flying airtronics for 30 years so I under stand those issues.on mine I felt the elev. We're too!big also.so I stripped the covering and cut off a 1/4" from the TE.and only have @ 3/16 " of up elev.I think this plane flys nicer when a tad nose heavy.

Air Sally

I added some alum tape to the exhaust ramps ...I'll airbrush some exhaust color to them and post a pick.

Cougar429

My Feedback: (3)

I did the same to mine during the build, as well as add some exhaust stacks. Those should have been larger, but were the only size alloy tubes in spares. Used insulation seal tape my friend that does AC gave me.

For some reason had trouble logging on last night to post. Seems O/K now.

Air Sally

Cool .trying to post pics of mine

Signofinfinity

Hi all,

Thanks for all the info....

I acquired an unused RB... With the 91fx.

What servos did you chaps put in? Metal gear? Or will the trusty 3001s suffice?

Many thanks,

George

Cougar429

My Feedback: (3)

signofinfinity, welcome. Can't wait to see some pics.

Only metal geared JR for the elevator and due to being the strongest and quickest digital I had in spares. The ailerons on mine have Hitec HS-5645MG digitals and the rudder is standard Hitec as that was the only one with a wheel fabbed for wire pull/pull.

Each aileron has its own servo so you could get away with a standard like the 3001. Since this one is not built for wild aerobatics the comparably slow .22 sweep transit speed may be adequate roll control as well. However, due to the loads on the tail I would look for something a bit stronger for elevator and rudder.

Good servos are relatively inexpensive now and that is true for digitals which give much better performance. The only concern is with their higher current demands, especially under load or stalled, (some real stompers such as what my friend uses in his turbine jets can draw in excess of 1.5A EACH!) so you can see where a well designed flight power system is mandatory.

I won't mention specific brands, but stay away from bargain basement digital and/or metal geared servos. There are some critical design factors that are often ignored with these. I have a box full of one such I acquired for a song simply as they are meant for non-critical apps such as throttle or grandkids toys.

NOTE: I run exclusively 6V on my flight systems as servo outputs are better, especially with long servo leads. Imagine will eventually go with HV to use LiPo direct, but for now stay with LiFE. Make the NiCad and NiMH packs utilized for so long go the way of the dinosaur.

Air Sally

im using metal gear digitials in mine ...read through this thread. throw away the stock elev. set up .cut the lower skin off the stabs and fix the issues in there,but a real C/F stab spar from CST.com(the composite store .com).put the elev servo in the back of the plane under the tail wheel. use short 4-40 push rods for the elev. and try to drip CA into as much of the wing as you can ,and reglue with epoxy the landing gear mounts. if you don't do these things your really nice looking plane wont last long. elve will flutter and plane will CRASH

Signofinfinity

Indeed. Thanks for the heads up. I was of the impression that MG was mainly for the gasers.

So, so I use mini servos hitec MG 85s....at 6v? Keeps the weight down... But torque in excess of 4kgs...

As power I was to use a six cell 3500mah of my turbine vampire, in the nose for CG and peace of mind....

I have the upgraded feathers which I will use, and planned on using a wood dowel, with 3mm rods and ball links...

LG is the modified later kit with half inch ply and ply rib doublers...which I will re glue as a safety measure....

I will do some servo hunting at my LHS for good MGs too. Yes I agree, I only use futaba, Jr and hitec. Recently had good success with ACE sevos MG on a 53cc gaser MSXR running at 6v. Ds1015 I believe... 10kgs output at 6v. The MXS is a 1.9m.

Will post some pics. This is an interim model as I wait for my Savex L39 !

Air Sally

also on RC Groups there is a thread in the glow to Eletric conversion thread that has more info ...read Corsair nuts posts whatch vids and I have a few pics in there too of the mods you need to do to keep the bear alive

Air Sally

don't use any kind of long push rod for the elev. any thing that was tried failed even C/F .put the servo in the back between the stab spars two small one if you have to but don't put the servo in the stock location

Cougar429

My Feedback: (3)

I have seen some put the elevator servos right in the stabs, but if done as per Air Sally and myself one single servo between the tubes will be sufficient, along with having all the linkages internal.

One other point I was worried about was the rather dubious metal used for the stock elevator linkages, (the ones that install into the elevators and exit inside the fuse). These seemed rather weak and chromed, as well, which tends to make them brittle. So far they are holding up with no problems.

Now, if I could only figure out some way to make the tailwheel retract...............

Air Sally

I trimed @ 1/4" off the T.E. of my elev. and recovered them after I did the " open stab " surgery on mine...I have not had any issue with the stock wire either ....but they do flex a bit ...so we will see how it goes

Signofinfinity

Thanks Cougar and Air Sally.

I see the point of the long pushrod.

I will stick to the servo in the tail.... One or two weight dependant...

The 'open surgery ' was on the retrofitted stabs?

Do you have a link to the glow to elec conversion?

Signofinfinity

I was considering modding the stab linkages.... Using cf or wood dowel.

Will get to the drawing board.... And will post some ideas.

Cougar429

My Feedback: (3)

I think if you read from the start both versions of stab were checked and if memory serves even the new offering suffered from substandard bonding and ribs of extremely soft grain. IMO, not worth the risk for the cost of one sheet of balsa.

I read of some filling the entire stab with Gorilla Glue. From my own experience there is a big chance for structural swelling if not monitored and held to shape.