It looks like your battery pack is a long stick. You could reconfigure your cells to get more weight up front.

Nick

I would try a 12 cell pack to help the ballance.
I have some 12 packs that are four sticks of 3 cells each in a square configuration, like a transmitter pack. That will get more nose weight and allow more of the weight further forward.

Reconfiguring the pack didn't help. You still need a fair amount of lead in the nose. I ended up swapping out the Jeti 30/3 for a 15/3. That shaved 3 ounces from the tail. On eight CP2400 cells it's drawing 44 amps static with the 8x6 prop. Less power than the 30/3 but I don't want aerobatics. I just want the plane up to thermal height.

The pack is made up in a brick and placed all the way forward. It still took 3 ounces of lead in the nose to balance. Of course, I could add two cells and take out the lead.

I can't figure out how they got this thing to balance with the spec gear. The instructions say you could put a geared speed 600 in it. I'd like to see how to balance that!

Projected weight is 63-77 ounces as per specs. Mine came out to 71 ounces. Hopefully I can get a flight or two in this weekend.

A graupner inline gear coupled to a sp600 ways only 300 grams with a controller!

If you put that in your plane and take out the elevator servo that is also another good ounce, i think she should ballance

If i read about your plane with the elevator servo erlier i would have said DON'T !!! Unless you plane on F5B style flying you don't need to keep the connections that short. You could have just used a bowden cable.

But 3 ounces of lead isn't all that bad. I have an electric plane that needs 4 ounces and i don't mind.

Good luck on the mayden!

300 grams is 10 ounces. Even with the elevator servo forward, I'm not sure it would balance. I'm using a 0.5 ounce micro servo in the tail. The Jeti 30/3 is 8 ounces not including controller. The 15/3 is 4.8 ounces. The controller adds another ounce.You're right, three ounces to balance with the 15/3 is not bad. It should fly fine. However, 10 ounces of lead in the nose with the 30/3 is too much IMHO! I don't see any advantage to gearing the motor in this plane. The max prop clearance is 9x6.

I bought this plane as a video platform. The thing to do is cut the nose and put the motor up front. The rear pod can then be used as a video bay. But, I can't do it! The glasswork is so nice!

Random thoughts.

Maiden flight today. Motor on and toss her forward. A little scary as she heads toward the ground. The motor pitches her forward. Needs to get on step and stable before pulling elevator. The Jeti 15/3 is plenty of motor to speck out quickly. Thermals were there and the Windex picked up the lift. Turns are tight even without rudder. Fast airfoil. Spoilerons definitely needed to land.

Balance is right on, however, Sal is 100% correct. The tail is understabbed. A little more forward cg should improve the stability as he stated in an earlier post.

I've decided I hate those Jeti brushless controllers. The brake is lousy. I couldn't get the prop to stop spinning. This is like a recurring nightmare whenever I use a Jeti controller. I'm going to swap out for a Kontronik.

The Jeti 15/3 motor is more than enough. However, I think I'll try a 15/4 to drop the amp draw. I think I'm pushing the limits of the 15/3.

A carbon wingrod would decrease the weight. It shouldn't be a problem since I don't plan on doing (intentional) aerobatics. I placed some tape at the wing/fuse. It's not needed. The fit is very secure, but, I was being cautious.

docphi: plane looks good and congrats on successful first flights.

I found that with Jeti controllers, the brake is enough to slow the momentum and allow folding props to fold back. I have an Old-timer with a fixed prop, and when I fly by slowly, I can hit the brake and see that the prop slows, but then it just begins to windmill again. I can't tell from the pic, but I am not sure if a folder would work with the tail in the way. Just a thought.

Good luck with everything, and thanks for the info.

Just tried a folding prop. The tail gets in the way. I just realized I didn't have the brake on! We'll give it another go before playing musical speed controls.

From my experience with all kinds of speed controllers i know that some brakes are better then others and that some are smother then others. If you do have a brake on your ESC it should be used the stop and fold a folding prop out of the airstream.

When using it with normal props, the prop will start to windmill shortly after you cut power agian. This is becous of the nature of the braking system. The controller shortly aplies full power to all three cooils and then cuts power all together. If there isn't enything holding the rotor down then the prop will start turning agian.

Also there are more things to look at before you blame the controller. Remember, the new Jeti's are top notch!

Kimble.

with the amount of work going into your Windex, I don't know if I want one now. seems like a PIA all the way around.

tim

Definitely not a PIA plane. Just the cg balance was tough. It limits the powerplants you can put in the tail pod.

I documented all of my progress in detail so it may seem like it was torture. It's like parents talking about their new baby to other people! The effort was definitely worth it. She looks great in the air and flies awesome!


Kimble, thanks for your input! I've got motors with Kontronik controllers that stop the prop and don't windmill. Maybe the Jeti master (gold label) controllers have a stronger brake? I'm using the white label controllers.

Motor tests are complete. I've tested the Jeti 15/4 and 30 amp gold-labelled controller. Spinning an 8x6 Graupner Cam prop on 10xCP2400 cells I get 32 amps off the charger.

Climbout is as brisk as the Jeti 15/3 on 8 cells. However, the amp draw is down from 44 amps. The max draw for the 15/3 as per manufacturer specs is 35 amps.

The gold-label controller seems to have a better brake. The prop stops no problem.

The extra cells from the 10 cell pack allowed the removal of the 3 ounces of lead in the nose for balance.

I really like this sailplane! Sorry if all my posts were overkill. Hopefully there was some useful information.

Sweet ride!

Is your old ESC the 40-3 opto? I have this one and didnt know it had a brake. bought it 2nd hand, no instructions. could you tell me how to enable the brake?

You may try adding downthrust to the motor to cancel some of the power-on pitch-down...?

Far4nugn,

Old ESC was the 40 BEC.

To enable/disable the brake put the throttle all the way up and turn on the transmitter. Now plug in the ESC/RX. Pull the throttle closed quickly. The ESC should beep once. This means the brake is on. If it beeps twice, the brake is off.

Thanks!