Can I have some top tips on installations please?

I am interested to know what can go next to each other and what needs to be separated (electronics wise).

Any good rules to minimise interference between onboard components. I am not too concerned about external interference issues.

Just keep your Turbine fuel pump as far away as you can from the Receiver and the antenna. Also try to keep the antenna away from any long servo leads.
Whatcha buildin'?

I'm just at the point of installing the servos in my Kangaroo. I want to run the servo wires down each side of the fuselage but this means that on one side they will run within 2 inches of the ECU/fuel pump. I'm a little concerned about this.

What about batteries/power leads? do these have to be kept away from other items or am I worrying about nothing?

I am sure someone can help me here!

Pleeasssseeeee

The answer is that there is no hard and fast answer to your question. All installations are slightly different, and every airframe has it's own unique restrictions because of physical size, CG requirements, and the type or equipment you are installing.
It is desireable to keep as much seperation as possible between the ECU and the reciever, between the fuel pump and the reciever, and between all of your servo leads and both the ECU and the fuel pump in order to minimize the possibility of EMI. In the cramped space of many of our models it is not always possible to achieve this though. The good news is that most modern ECUs have been designed to limit their emmissions in our frequency range, and most turbine fuel pumps are equipped with filters to minimize thier emmissions as well.
Do your best to keep things seperated, then make sure you range check the model with the engine at several different throttle setting, and with the turbine shut down. If there is a noteable discrepency between the amount of range you get under different engine conditions then you know you will need to track down the problem before you fly the airplane.

Not exhaustive but some ideas. A quick brain dump in the 10 mins before i go out so apologies for lack of structure /grammer/spelling

Do not run the aerial in parallel with other wires/metal includes carbon fibre.
If you can get a right angle into the aerial lead this is good news improving reception and giving the aerial 2 planes of operation. whips achieve this or routing part of the antenna along the wing.

The receiver picks up it signal via the aerial this is relative to the receiver earth, the very point your long servo lead is connected (zero volts) it could also be of a similar length which should be avoided if poss. This can lead to the signals you want your receiver to detect being cancelled out by signalls appearing on the servo leads. solution : use opto isolators from the servo leads or wrap a few turns of the servo lead through a ferrite ring or tube. This makes sure that servo leads have a high impedance to RF signals, make sure the ferrite is close to the receiver.

The ferrites can also prevent any noise generated inside the servos getting back into the receiver.

Think about interfering sources in your fuselage i.e. wires in which high currents are being switched /glow/solenoid/pump/lights/ECU/servos keep them as far as possible from receiver or aerial. Any interference from these sources will drop according to square law, so the bigger the distance the less chance of interference. I have a noisy harness on one side of the fus less noisy on the other. Make sure supression is fitted to pump and solenoids usually a capacitor is all that is needed manufacturers usually give advice here, follow it to the letter. Motors are notoriously noisy.

Contraversial -- but i use a seperate battery for servos and receiver using an opto-isolator, i know some will say this inceases the possibility of a failure (more things to go wrong). But with only one battery and a stalled servo, or lots of servo activity drawing many amps I would rather my receiver has a clean and independant supply, than take the risk of the voltage dropping to the receiver reducing its performance.

Look out for metal to metal moving connections. these can generate RF noise unless they are in intimate contact with each other, a metal horn to metal clevis would be an example, if you have these make sure electrically the two sides are joined together using flexible braid.across the moving connection.

...... all for now hope this helps.

John

My installation is in an Avonds F15 but its near enough to apply to the Kangaroo
reciever is at the nose all servo leads go down the left side of the fus and power leads down the right
turbine ecu is 12 inches behind radio reciever and its control leads are on the right side but 3 inches above the power leads
pump is situated as far back as it will go on right side and well away from servo leads
ariel goes down left side to a whip antenna just behind rear of cockpit.

Have seen some installations where the servo leads are wrapped in tin foil but not sure if that really works??
turbine case is grounded to airframe
Radio is 9zap pcm.
this works for me have been flying this model for a year now with no problems

Hope this may help you
regards
Brian

Brian,

Could you please post some pictures of your installation in the Avonds F15?
I'm building a Avonds F15 and I don't see were to put al this equipment(CG, space etc)

Won't the carbon strips in the nose interfere with your arial?

You would help me alot with some pictures.

Thanks.

Regards,

Martin

Hi Martin

No problem will take some over the weekend and post for you

all cables run above carbon strips and turbine used is an AMT Mercury hp from AMT Netherlands
so maybe different from your installation

Regards

Brian

Hi Brian

What is the purpose of the carbon strip? it could act as a noise collector which could then be capacitivly coupled into nearby wiring. I have seen this sort of thing recommended before, even using aluminium tape, but can't see how it provides an effictive screen unless the cables are fully enclosed and bonded to ground at one end (same principle as coax) this seems total overkill and gives a big weight penalty. Might be missing somethying so interested in your views.


Something I didn't add in previous post, twisted wires are better than flat ribbon wires on long servo leads, to minimise propagation of interfering signals.


John

Thanks!, that's great.

I'm gonna use an Jetcat P120, installation will be the same for the greatest part(I think...)

Sorry to confuse you the carbon strips are the reinforcement Philip lays in during manufacture
remember this model started life as a ducted fan.

Yes im not convinced about using aluminium tape for your very good reasons like you say total overkill.

Brian

More pics
In all my future jets i am going to use the new electronic air valves for a much simpler installation
and i highly recomend the use of a FOD guard for this model especially if flying off grass

Thanks Brian,

You didn't have any problems with the CG location? I heard the Avonds F15 is easily noseheavy(if you stick with philip's layout).
Where did you put your rx batteries?

Regards

Martin

Hello Brian,
Thanks for posting the pictures.
Please answer a couple of questions for me.

1) I noticed the nice little dual pressure gauges. Did you purchase them in the UK, if so where ?

2) Also, you seem to have 2 Rx switch harnesses. Do you run dual 5 cell Rx packs and a battery backer (glorified common cathode diodes) or do you just stuff 2, 4 cell packs directly into the Rx ?

Thanks.

Jules.

Hi Martin

CG is 29.5 inches from edge of tail cone curtesy of Johnny Hernandez who spent a lot
of time trimming out his own F15 and its spot on
I use two 6volt packs 2400ma thro a backer which drops them equally
these are located just behind the rear engine bay former one either side (see pic No2 charging plug just shows) i installed
everything and used the two batteries for final balance tanks empty gear down.

Tanks are Dubro 32 oz with BVM UAT, front tank empties first leaving mains to drop equally on CG
ensures no trim change for landing this gives me 8 minutes flying time with time for two circuits.

Elevons are massed balanced with lead shot and epoxy
elevon control servo`s are Futaba 9420 digital buggy servo`s
the rest are standard ball raced 3001 servo`s and i use a cheap £30 pounds piezo gyro on the steering servo

regards

Brian

Spartan missile
Gauges are from BVM http://www.bvmjets.com/ but they are really Festo modified
to fit our small bore air lines,found them in his monthly specials

Yes i use a backer and they are "Y" leaded into the reciever ( 5cell 2400ma )

Well, here is the latest install on the turbine trainer that my buddy and I designed, we hoping for the first turbine flight tomorrow.

Chris

Now THATS A NICE LOOKIN' HOMEBUILT!!!!!!!!![8D]

Thanks very much for all your help guys. The photos are particularly helpful. It makes me realise just how much room there is in a Roo fuz.

Also saw a clubmates reaper at the weekend. It really helps to see these things close up!

By the way, the Reaper was absolutely awesome. Hope my Roo is half as much fun.

Have fun and post some pics when you`ve finished it

Regards

Brian