Reno, my cg with no fuel is at 2 7/8" behind LE. It started further back and needed down trim to fly level. The plane was never twitchy at the aft cg, just wanted to keep climbing.

Hey Ron, just saw your pics.

Isn't there a rule that says I can claim that engine for $100....

I think I'm exempt from that rule too.

But fitting a 9x6 on there is going to be the real chore!

So I guess I'll have to throw a TT Pro .25 on it.

Reno,


IMHO I would have used a z-bend on the servo end of the tail linkage... you have a ball joint on both ends... and frankly nothing, save the wire thread/ball link plastic friction on both ends prevents vibration from changing your elevator pushrod length/trim inflight on one or both surfaces. While it may work AOK... may isn't good enough for me... I would put a Z-bend on the servo end. Not trying to be critical... just want you to have a good experience.


Dan

Hi Dan.

I know you guys like Z-bends, I don't care much for them myself. I've always used the double-ball or ball/clevice setup with success. (No re-trimming or double-centering.) Remember this is a .25 club racer.

But, I'm also putting together a 424 class plane, so if need be, I will resort to the Z's. Also, I'm having a little trouble understanding your last post. Can you clarify how the pushrod length/trim will change? As I look at the pushrod, one end screws while the other end unscrews. Maybe I can lock the whole thing up with a nut at the ball joint on each end?

Thanks.

Ron

[8D]

A nut would work, so would some kind of glue or goop on the threads. Nylon ball-links don't turn as freely as metal clevises, but in theory one of them could unscrew itself. (You're right; the trim wouldn't change until the moment the connection actually broke.)

Some might scoff at the notion that a pushrod could rotate by itself. The other day I was bench-running a Q500 with the wing off, to diagnose a fuel draw problem. This airplane had a cylindrical fuel tank in it. As soon as the engine got up to peak rpm, I could see the tank begin merrily rotating in there, twisting the fuel lines into a knot. Mystery solved! [X(]

Duane Gall
RCPRO

did ya' put a tach on that tank?

Can it idle like a cub?

Ron,

You are corect about them not changing trim... they will movre given enough time and vibration. By the way... I have trouble understanding myself sometimes!


Z-bend Dan

Hi Dan.

Thanks for the good advice. I'll definately keep it in mind.


Duane,

I too have the round Jett tank. I'm going to install it tonight. What are your suggestions to keep it from spinning? I was thinking of zip strapping some soft foam around the outside of it prior to installation. Then jam some in between the fuse and tank. Think that'll work?


[sm=idea.gif]

Hey Dan!

Sorry we weren't able to get together this weekend, maybe next time.


BTW, I went down do the park with my Stinger and trimmmed out my new Mega 4 motor.

We should fly these thigs too!

Check it!

http://www.youtube.com/watch?v=C4DzV6UrFgA

Ron,

I wouldn't worry about the tank spinning unless it actually happens. This was the first time it's ever happened to me, and I've used cylindrical tanks for years. Sometimes it's "just something" in the installation that transfers vibration in whatever way causes the thing to turn ... hard to predict ... unlikely anyhow.

On mine, I just cleaned it off with lacquer thinner and put a couple of dots of Shoe Goo (a/k/a E-6000) where it was touching the inside of the fuse. So now I have a semi-permanent installation. But because it's a bladder tank, I don't have to worry about foaming of the fuel, so I can attach it directly to the fuselage structure.

Duane Gall
RCPRO

Thanks Duane.

That just gave me a good idea utilizing some double sided tape, a couple zip straps, and a little foam.

You know, for preventative measure.

Ok just finished up my Pred 2. Will put her in the air tomorrow. She came in at 3 lbs. and 14 oz. A little off the 3.75 mark but o well. Have a TT-40 Pro with nelson muffler (yes I know the rules) just having some fun for now. Made my own bladder tank with baby bottle liner. Put it on cg. have Hitec receiver , and has HS 225MG on all but throttle. Futaba 600 ma battery. Used stock push rods on tail. Have HPI switch with volt monitor. Used stock wheels. Have lots of decals to make her look good. Will take off on high rates once she is up I.l switch to low. Well thats about it . Wish me luck!

Good luck. Let us know how you end up liking it.

Hi Guys, I Have A Predator Just Finish Putting It Together, Im Just Wondering The Wing Plate That You Get To Hold The Wing Down With, & Also To Hold The That Back Plate Where The Servos Are Mounted, I Have Used Another Way 0f Attaching The Plate For The Servos. So Could I Get Away With Not Using The Wing Mounted Plate. 0r Should I Still Use This Plate For The Wing So The Wing Mount Screws Dont Pull Through The Wing!!!

Vendata I used that plate on mine so I really don,t know what would happen if I didn,t. I,m going to CYA and say don,t omit it. Ok now let me tell my story of how my day went with my Pred 2 first flight. I started out flying my trusty old Sonic to worm myself up. Thats where it all started. Made 10 laps then disaster struck. The wing folded. She spiraled in to the mud. Dam that made me mad. Got all the parts and set down for a wile .Fueled up the new Pred 2 and said what tha hell. Off she went . Trimmed her out . so far so good. Engine still to new to tell if she has it or not. but every lap she seen to get faster. So I landed her and headed back to the pits. My good friend Ray Just had to have my Nelson muffler. So I loaned it to him. He said Dub Jett is trying to put together a race class that will allow both 424 and 428 Q-500 to race together. It will be interesting to see how that turns out. Well so far I like the Pred 2.

Hi Ya Budman27, Thanks For The Imformation 0n The Predator. I Will Glue The Plate 0nto The Wing,
Just Incase. If I Dont Use It, Its Just My Luck The The Wing Bolts Might Just Pull Through The Wing.
& I Will Loose The Whole Plane! Any Way My Predator Weighs In At Just 0ver 3 1/2 LBS. With A 46 0S AX & Used A 600 MAH Battery Pack! 40Z Bubble Tank. I Am Going To Test Fly It This Weekend, So Here's Hoping Its Faster Than My Viper With The Same Gear!

Budman 27,
Where did You Set Your CG 0n Your Predator. I Have Set Mind At 2 3/4 From The Leading Edge.
How Far 0ut Were The Trim's. I Read Some 0ther Guy 0n R/C Flew His Predator & It Climbed Like
Like A *****. Did Your Predator Climb To The Moon!!

My cg is same as yours . She really was not that out of trim. on take off she really didn,t balloon up to much like I here other guys talk about. I just need to get my Nelson muffler back from Ray so I can turn and burn if you know what I mean.

Budman 27,
I Will Let You Know How Mind Flys, 0ver The Weekend Providing The Weather Is 0k.

If you weren,t so far away I would go with you. May the wind always be to your back brother. Good luck. Let me know how it went.

Not on takeoff.

There you go. Get er dune.

Hope all you dads out there have a safe and happy Fathers Day.