HELP! I need more thrust!

[moy71]

Hello all.

Tried to fly my GP Electricub II (wz ailerons) today. It is powered by a speed 600 motor (geared 3:1) and 2400mAH 7 cell battery. I am currently using 10x8 master airscrew prop as recommended by the manual.

But the damned thing had a hard time taking off. It rose about waist-high (& it was a long shallow take-off at that) , then simply wouldn't go any higher. So i figured i need more thrust. I read somewhere that by switching to a 10x6 prop, it will give me more thrust.

Can anyone else offer any suggestion or agree with a prop switch?

rgds

[jgdvrs]

Hi There

Did you happen to check your prop for correct mounting? I have put one on reversed and caused that sort of problem...

Just a thought

Jamie

[Dave Robelen]

Hi Moy,
If you do switch props try to add some diameter as well. An 11-7 might be a reasonable compomise. Is the 7-cell battery normal for that setup? It sounds a little on the low side (compares to 8 or more). Dropping toi a lower pitch at the same diameter would only be suitable if the other were drawing excessive current and really bogging down.
Regards, Dave

[2NG]

Moy,

How is your motor mounted to the Cub? Is it straight, or with a little bit of down thrust? (where the motor is slightly nosing down) Change that prop. Your gonna collect more troubles with that prop.

[moy71]

i bought a couple of different props today. a)10x6 master airscrew prop for electric motors (with undercamber) b)9x6. the motor is mounted with a slight downward angle, and a slight point to the right as per the manual.

i was also thinking perhaps it could be a weight problem. too heavy maybe. but according to the manual it should weigh betwn 1.4 to 1.6kgs.

the CG should be 2 & 7/8" from the LE. but i do not have a real tool to test the CG. i just use my finger to lift it up at that point.

oh well, if it doesn't fly well, it'l still make a good display piece over the living room!!!

i am thinking of getting the wattage cub if this one doesn't fly. at least that is is ARF and not a kit.

[2NG]

GP has a nice CG machine. In my opinion Big Hobby manufacturer making more money. Let beat them at their own game. Let's make or own CG machine:p

Seriously, this is how I get my CG. (The airplane below, is from a bud of mine. Rodgerdoger, with Generic Cub) with my CG I put a pencil eraser on the tip of it:)

[moy71]

hi 2ng

that's a real neat looking CG tool. it looks inexpensive too! so basically its just 2 long sticks with eraser tips on top & a broad base at the bottom?

i will make my own today!!!!

thks heaps.

[2NG]

I love to fly, Moy71. I hate the price:( , but I am glad that you like it. You can also make a slider, so that a ruler can slide freely.

[Shiraz]

Hi

LRK Motors (they are specially wound brushless motors) are supposed to give higher torque than ordinary motors. Some related motors can be rebuilt from electric motors scavenged from CDROM drives - perhaps you should add one more dimension to your hobby - why not build your own motor as well(!). Believe it or not there is a group on yahoo(lrk-torquemax) of people interested in the ultimate torque/thrust/... then you can use a propeller with a greater pitch and get what you need... and it does not have to be expensive either, if you have the patience to do it yourself...

Regards

Shiraz.