[MarkToo]

I've recently acquired a nice gas set up, and find myself a little over my head.

Airframe is a Patty Wagstaff 1/4 scale Extra 300 from Great Planes.
Engine is a DA50

Servos are all 5645MGs. Two rudder (fuse mounted, not pull-pull), Two elevator, and two Aileron.

There is also a smoke system for it.

It has been partially disassembled, and I'm putting it back together, and want to make sure I do it right the first time, so am looking for your input.

I have a servo programmer for the Hitech Digitals.

I'm not afraid to set up the radio programming or the servo programming, but want to make sure the aircraft in general is assembled in a safe and reliable way, and in a way that will provide the best possible results.

My main questions are as follows:

1. I have seen optical isolation set ups for ignition kill switches - do I need to do this, or can I just servo the manual ignition switch as was done before?

2. Is there any reason I cannot run "Y" harnesses for the control surfaces?

3. The choke is currently manual - is this fine, or should it be servo actuated?

4. There are 2 power switches twinned with a single lever that extends outside the cockpit area (not including the ignition switch), why two switches? Would one be for the smoke system?

5. Does the receiver I use matter? (I'm running 72 MHz still). Do I need anything fancy? Can I use a JR700?

6. Are there certain ways to set up the electronics redundant? Is it necessary? Is it smart?

7. Should I be using some sort of power block for distribution?

Any advice - especially specific answers to the above questions, is appreciated. I hope my questions are clear, as I don't yet know what the pitfalls of a gas set up are, and I'm just trying to head off any possible problems by asking first.

Thanks in advance.

Mark

[RAMJET]

1-- opti kill is best & light for small planes /be carfull with type as some appear to be better suited for the more tollerant 2.4 radios

2-- Y harness .should not use as you lose the ability to mix & lose redundancy

3--keep the choke as it saves weight

4--redundancy /nothing can beat 2 recievers &2 batteries .each running 1/2 the plane/

5--nothing wrong with 72 /but they seem less tolerant to interferance so keep ignition far away /also cheap now so doubling recievers is less money& lighter than power expander .

6--1 through 5 should do ok

7--50cc don't need the weight

[yakityyak]

1. Not needed but a good idea, I would chose the optical switch over the servo as it is a solid -state system (no moving parts)

2.Y-harnesses are silly, there is no reason TO use them. Use the proper rx for the setup and mix. Its hard to achieve a bind free setup with y-harnesses, simple with mixes/matchboxes/equalizers.

3.Choke is good the way it is, make sure its easy to use.

4.Switches are a common point of failure, two is better then one, but one FAILSAFE switch is better then all of the above. Redundancy is important, but remember that the more points of failure you add the higher the risk of failure. I would remove the switches if they are not failsafe. Some rx's come with a failsafe switch installed and provide for two battery leads (redundant) but they are........

5.Not 72MHz. MY opinion is that 2.4 systems are more reliable and provide a much more robust and secure connection and because of that I wouldn't use anything else. (just my opinion)

6. and 7.
Again, only my opinion based on readings and my own expierence with the products.... The most proctected, redundant, reliable, robust and safe 50cc system is the following.

Your choice of JR or Spektrum transmitter with an AR9100 rx, powered by (2) 1100mah A123's through the two leads using EC3 connectors.

Thats it!

This has all the benefits of the powerboxes, redundant power, failsafe switches, and properly regulated rx power while providing ample power to your servos and also allows for the use of the Flight Log from Spektrum which will allow you to see just how good your setup is working.

Hope that helps and good luck!

Andrew.

[MarkToo]

Originally Posted by yakityyak

Your choice of JR or Spektrum transmitter with an AR9100 rx, powered by (2) 1100mah A123's through the two leads using EC3 connectors.


Andrew.

Ok, that sounds like a route I can take.

I should have mentioned that I'm using a JR10X (heli version) TX, and although my stuff is 72MHz, I do have a Spectrum 2.4 module for the TX.

I guess I could pick up an AR9100 and just swap the TX module when I want to fly the Extra.

Thanks for the tips so far......

Mark

[michel gravelle]

Hi Mark

I think that this question is relevent , what receiver are you useing and can it handle a power surge ? And from what I have learnt PPM is OK , BUT, absolutly NO metel TO metal . Anyone wishing to correct me , please step in

Michel

[MarkToo]

I don't actually have a receiver dedicated to this plane. I do have a couple JR 700's that I was debating using but, the AR9100 sounds like it accomplishes just about everything I need to do.....

[yakityyak]

Originally Posted by MarkToo

I don't actually have a receiver dedicated to this plane. I do have a couple JR 700's that I was debating using but, the AR9100 sounds like it accomplishes just about everything I need to do.....

And you'll save $$$ over buying all the individual components too!!!!

Andrew.

[michel gravelle]

Hi

I do not pretent to know what I am takeing about . I have seen a few planes go down , and it was determind that there reciever was too small for the requirement of the plane . Who doesn t want to save money , When I put my TF P-51 to-gether , I had no idea what I was geting into , and I had no funds to buy a new radio system . I ended up buying a smart fly , I really had NO CHOICE . My JR 7202 was built to handle 60 size aircraft , thats why the Smart-Fly With to-days high end recievers , you do not need this .

I just thimk that it is better to ask than not to ask , thats all . I will let you ask the question

Michel

[bobreib]

Optical kill switches have another advantage in that if your rx systems should fail it will kill the engine.
Even if the rx battery dies, or is disconnected, the engine will be shut off. ( happened to me, it does work )
Far better than mechanical kill switches, which can sometimes cause intermittent problems with vibration.
You also get better electrical isolation which is quite important with 72 mHz receivers.

[MarkToo]

Michel,

From what I've been reading tonight about the AR9100, it would seem that it is designed for this application, and should have no problems handling my smaller, large scale plane.

I'll just have to sort out the ignition system. i.e. switch, battery size/location, charging options etc.

On a side note:

One thing I did notice while setting up the .60 size extra that I have, is that I had to "throw away" the AUX1 port on the RX, as it was slaved to the throttle (remember heli radio), and I couldn't see a way to unlink them. Because the little Extra has independent ailerons, I had to learn how to mix them to make it work. So, unless I'm missing something, when shopping for receivers for aircraft while using my heli radio, I must keep in mind I need one more channel on the receiver than I'm actually going to use.?.?.?