North American F-86 Sabre (Tomahawk)

It was a beautiful day so the F-86 had a day at the field for a photoshoot and some tests. The cockpit is build light and is not that strong so i hoped that the airflow did not move parts around. Without the intake they did but with the intake everything was perfect. The hydraulic simulation on the geardoors was looking great also. The best photos are created when flying so i made 2 flights.

WOW!!!! Congrats!

Hello Tadango,
fantastic flight, awesome modell - like a dream!
I hope we will see us in MC!
Jetgruß Peter

With a high wind, especially cross wind, full flaps is to much during the landing. This is what happens

fly fantastic you jet!!! very nice!��������

Normally in flight photo's with low light are terrible. Sometimes they are not

During the last show i discovered that the lightweight 2s LiOn packs can't handle the large servo's when they are 60% depleted. I had a very scary moment where i applied flaps to slow down and the sabre dove to the ground (normally is stays level) and applying UP did nothing..... There was a low battery warning on my transmitter so i quickly removed the flaps and then i could level the plane. When i slowed down i applied flaps slowly and made an emergency landing. On the ground the logs showed that the 2 packs reached 6.4v when applying flaps, that is to low.

I replaced the receiver batteries with the LiPo's from the first flight because they can handle the current much better. I can also notice that the mAh consumption of the LiPo's is less than the LiOn's because they keep a high voltage. Although the LiOn's have a higher mAh rating they are a bad choice.... They work great on the ECU and lights but not on the high powered servo's.

Thank you for sharing this info; good to know!
Jetgruß Peter

what specs do your li-ion batterys for rx have?
for bigger jets i prefer (2packs) 2s2p li-ion charged with lipo-program (as recommended by experts). but i use 6v-servos, no hv-servos.

i´ve got your specs in your statement above.
as far as I know there are no 18650 cells with 3000mah and realistic 30ampere rating on the market, there may be a misinformation. the 3000mah i know are rated with 10 ampere.
the ones i know rated with 30ampere are distributed by hacker (former irc-emcotec) with 2600mah.
alternatively from the same distributor should be good 20700 series 4250mah with 20ampere-rating, only slightly more weight.
brg
thomas

Tadango schrieb:

During the last show i discovered that the lightweight 2s LiOn packs can't handle the large servo's when they are 60% depleted..

Zum Vergrößern anklicken....

Do you use a power regulator (such as Powerbox, etc.) in HV configuration with LiIo's?
I'm asking because I had some Jeti PowerIon Batteris connected to a Powerbox Mercury with 8 HV servos on a testbed, and the voltage was already unstable when I just moved the sticks with no flaps attached.

I decided to operate that Powerbox with LiPo's as well instaed of the PowerIon packs.

steinix schrieb:

what specs do your li-ion batterys for rx have?
for bigger jets i prefer (2packs) 2s2p li-ion charged with lipo-program (as recommended by experts). but i use 6v-servos, no hv-servos.

i´ve got your specs in your statement above.
as far as I know there are no 18650 cells with 3000mah and realistic 30ampere rating on the market, there may be a misinformation. the 3000mah i know are rated with 10 ampere.
the ones i know rated with 30ampere are distributed by hacker (former irc-emcotec) with 2600mah.
alternatively from the same distributor should be good 20700 series 4250mah with 20ampere-rating, only slightly more weight.
brg
thomas

Zum Vergrößern anklicken....

Sony Konion US18650VTC6 3120mAh - 30A. The main issue with LiOn is that the voltage drops when the battery get's empty. A LiPo will hold a much higher voltage until it is really empty. So when the LiOn is about 50% empty the voltage drops and the servo will need more current for the same power. This results in a higher load and even bigger voltage drop. 2s2p might work fine but i cannot handle the weight. The 20700 sound like an option maybe, but LiPo's have never let me down before

UweHD schrieb:

Do you use a power regulator (such as Powerbox, etc.) in HV configuration with LiIo's?
I'm asking because I had some Jeti PowerIon Batteris connected to a Powerbox Mercury with 8 HV servos on a testbed, and the voltage was already unstable when I just moved the sticks with no flaps attached.

I decided to operate that Powerbox with LiPo's as well instaed of the PowerIon packs.

Zum Vergrößern anklicken....

I use a mercury also, so stabilized voltage (until the battery drops). I use high voltage servo's and my voltage is set to 7.4v, but my receivers report 6.8V. The stabilizer always has at least 0.4V (if a remember correct) less output than input voltage, to with 6.4V from the batteries there is only 6.0V for the servo's. Sadly i did not log the receiver voltage before so i don't know how low the servo voltage got during the low voltage situation.

as i thought: the regular rating of this sony cell is NOT 30ampere, it is "only" 15ampere! You may go short for some seconds (boost) to 30ampere not to damage the cell.

Some nice photo's from last weekend:

And some nice photo's from last weekend. Probably the last foto's for this year.....