hey guys im dave from australia. just joined the forum after lurking for a few weeks lol.

anyway im new to rc flying. i bought a skyartec skyfun jet and im learning with that for the last 3 weeks. crashed many times but im starting to get the hang of it now. i also have a cessna 182 which i took up recently and crashed it on the landing. nothing major though.

i have a few questions but i wasnt sure where to ask.... hopefully this is the right place?

id like to build a new skyfun jet but install retractable landing gear on it for ground take offs and landings. the one i have now is hand launched but id like to try and mod one myself.
ive been looking at hobbyking website and theres alot of cool stuff on there. i want to take this off from short grass or a cricket pitch and as im kinda knew to all this would anyone be able to give me advice on what sort of landing gear would work best for this?
the jet is foam and it runs on skyartec 7 channel receiver. will i need a different receiver or can i just get landing gear and put straight into it. i assume im also going to need servos to run the landing gear correct?


sorry for all the questions but yeh its all knew to me so id appreciate some advice.

To add a retractable gear to a little foamy would require building in a structure to support it. It may not even be possible to do within the confines of the jet. Besides, it will add weight which will hurt the flight characteristics. It's better to buy a plane originally designed to have a landing gear. Welcome to the hobby though. It's a blast.

hi jester
thanks for the welcome.
yes i fully understand id have to mod the plane to make this work and also might have to put a bigger motor in also and im willing to give it a go if anyone as any advice for me and what sort of landing gear and stuff to use would be great
thanks

It's not just a bigger motor. Any time you add weight, you change the power required to fly that plane. This includes the motor, most likely the ESC, and the battery capacity and C factor. You will reach a point where it won't fly no matter what you do for power.

CGr

Consider the watts per pound guideline:

You can determine the power requirements of a model based on the ‘Input Watts Per Pound’ guidelines found below, using the flying weight of the model (with battery):

50-70 watts per pound; Minimum level of power for decent performance, good for lightly loaded slow flyer and park flyer models
70-90 watts per pound; Trainer and slow flying scale models
90-110 watts per pound; Sport aerobatic and fast flying scale models
110-130 watts per pound; Advanced aerobatic and high-speed models
130-150 watts per pound; Lightly loaded 3D models and ducted fans
150-200+ watts per pound; Unlimited performance 3D models


So, if you have a plane that weighs in at 25 ounces. That works out to roughly 1.5 pounds. To fly this at sport aviation levels, it will take 1.5 X 110 watts or 143 watts. If you use a two cell LiPo, that's 7.8 volts (nominal). 7.8 volts works out to a battery capable of supplying at least 18 amps. So, a 2000 mah pack is pretty much minimum for this plane, and you have to consider how you want to fly it at that and that's where the C factor comes in.. how long and how much burst power do you want/need? A three cell Lipo will need less current.. but you get the idea, i'm sure.

It's not as simple as just putting a battery on the plane and trying it out. You chance burning up both the motor and the ESC with the wrong selection.

Remember that when making weight measurements (not estimates, unless you know exactly what each component weighs), everything has to be considered: airframe, motor, esc, battery pack, receiver, servos, everything.

Read this thread. It has some pretty good information on selecting power for electric aircraft. You will probably recognize the above as being cut and pasted as a reply.

http://www.rcuniverse.com/forum/m_10376559/tm.htm