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Old Aug 01, 2008, 07:49 AM
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Basic Giant Scale Power and Electronics Setup

I am getting ready to start my first gasser build on a Hangar 9 Sukhoi. I have been building electric for a while, including giant scale electric, but I've not done a gas plane yet.

For large scale electric I'd go with something like a SPIN ESC for motor control, and then something like a Spektum AR9100 reciever/power management module to provide power to the servos. Both of these units are top end for electric setups and very reliable. The AR9100 has up to four integrated recievers and this is one of the main reasons I like it. Never had a hit of any type.

So, I will be flying a DA 85 on the Sukhoi and here is what I am wondering:

- do I need a dedicated battery for the engine ignition, or is there a power expanded way to get power to the ignition?
- can I use something like an AR9100, or do I need to go to a reciever and power expander combination?
- I read a lot about ignition cutoffs, and I assume this is a key safety feature for gassers to take the ignition circuit out. I assume this is mandatory.
- I also read a lot about plugs and circuits which let one re-charge batteries while still in the plane...is this recommended?
- One of the main reasons I am switching to gas is for smoke. Can anyone recommend a hassle free smoke setup?
- What am I forgetting?

Appreciate the help.

dan
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Old Aug 01, 2008, 03:03 PM
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Me too!

I am also considering a large scale gasser including the Sukkoi! I've got a question about dual RX batteries. What is the purpose of this with one RX? Will my DX7 handle this plane setup okay? Can I run a 9 channel RX with the 7 channel radio? Thanks guys!
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Old Aug 01, 2008, 03:27 PM
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you want a dedicated ignition battery. some guys are using fancy combination and expensive packs, but nicads or nickel metal work just fine at a fraction of the cost. 1500 Mah or so on ignition, and a couple for the receiver. electronic ignition cut off is a good idea - it is the best way to kill the engine. there are several that work fine. the purpose of dual batteries (and switches) is to provide redundancy for the system. not sure if da sells smoke pumps, but the set-up is pretty straightforward.
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Old Aug 01, 2008, 11:19 PM
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Got my Sukhoi in the mail today....

Very cool plane to look at, and impressive in the extent to which many things are already built, I would guess that there are about 2-3 nights of work taken out of the build from the get go.

- all surfaces prehinged
- aileron and elevator halves hinged and sealed
- aileron control horn posts installed
- cowl mounted and screwed down

Bad news was that the wing box was perforated and my left wing had a hole in it the size of my fist. Rather than ship back I took the covering off and repaired the insides, then replaced the covering. The perforation was on the bottom side and was all ultracote silver, so I patched it up pretty cleanly with some ultracote I have from another build.

The only other bummer is that the cowl is dimpled downwards on top, and I do not know a way to fix this. I will send Hangar 9 a note and see if they will replace this.

I also had some large scale "Red Bull" decals saved away from another build I never got to, and I put these on the wings and elevators....looks extremely cool. The Sukhoi is already borrowing the Red Bull rising sun, so adding the bulls looks awesome.

The DA 85 also looks nice, however, I am an absolute newbie when it comes to gassers so I am not sure exactly what I am looking at.

I am also looking at replacing the aluminum wing tube with a CF tube. The aluminum tube is tight and relatively heavy compared with other large scale planes I have flown. This will save a few ounces.

Regarding power management on this plane, I had a long conversation with Josh at K/C hobby in Archdale N.C., and here is what he told me.

- I must use some sort of switched battery for the ingition circuit. Josh recommended a regulated 2 cell lipo and an MPI switch with charging circuit.

- For servo power I can continue to use the faultless AR9100 I have been using for other applications, however, I probably should be using regulators to control the lipo voltage. This being said I have never had an issue flying with Hitec 5955TGs and the AR9100 without voltage regulation.

- If you are moving from electric to gas, you need to gear up for dealing with gas. So, you need a pump, some extra fuel line, in line fuel filters, a fuel dot for refueling, attachments for you gas can and probably a few other things I am not thinking about.

I am looking forward to turning this motor over and also adding a smoke system to this plane.

I will attach some pics as soon as my wife gets back with the camea.

dan
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Old Aug 03, 2008, 02:22 AM
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I'll use my 50cc plane for an example set-up and try to answer a few of these questions.. I've had the plane for a long time, and it's proven it works for me.

Q- do I need a dedicated battery for the engine ignition, or is there a power expanded way to get power to the ignition?
A--- A dedicated/isolated battery for your ignition is recomended to alleviate Rf interferance.. it was recomended to me in the manuals I got with my engine to keep the Rx and any radio components at least 12" from the ignition module/engine.. I use a PCM Rx and have never had any problem..

Q- can I use something like an AR9100, or do I need to go to a reciever and power expander combination?
A--- This would fall into a dedicated Rx battery category.. really nothing fancy is needed here other then deciding on 4.8volts, or 6volts..and the type of battery..Nicad, Nickelmetalhydride, or LithiomIon.. I wouldn't use LithiomPolymer..even a 7.2volt2S is way to much voltage..and you don't need all that reserve for bursts..servos don't take take the amperage to operate like brushless motors do.. and it is recomended using a regulator for 6volt system.. 6volts at full charge buzzes most systems without regulators.. it works without.. but..I'd use one..
If your going with newer lithiom-Ion technology just follow manufacturers instructs. 6volts gives alot more torque for your servos..I recomend it for any bigger plane.. I know Hitec for sure gives torque specs for both voltages on each servo.

Q- I read a lot about ignition cutoffs, and I assume this is a key safety feature for gassers to take the ignition circuit out. I assume this is mandatory.
A---Yes.. it is mandatory, by most sets of rules I've seen.. and I've had my plane inspected before meets and events for such a device.. of which I have 2 ways to kill my engine.. one is the optical/electronic device through the Tx... the other is the engine is set up to mechanically shut down at low-throttle/trim.

Q- I also read a lot about plugs and circuits which let one re-charge batteries while still in the plane...is this recommended?
A--- Absolutely.. You don't have to "change" batteries out for charging.. there's several companies that make devices that house charging jacks and swithes..MPI makes a great unit that's pretty bullet-proof.. you'll want 2 swithes.. one for ignition the other for the flight-pack. For charging you just plug your charging jack into the side of your plane.. and you'll have 2 of those.. one for your ignition the other for your Rx.

Q- One of the main reasons I am switching to gas is for smoke. Can anyone recommend a hassle free smoke setup?
A--- I don't have enough experience to share much info on that.. not quite sure what's on the market these days.. most mufflers that are available for the new generation of gas engines are equipped for retro-fit smoke systems though..its just a matter of finding the system that fits your app.

Q- What am I forgetting?
A---Gas can, oil, chicken-stick(crazy not to use one), some sort of leash for your plane so you can tie it off when starting..I use a long dog-leash.. and just loop it around a pole and gently around tail feathers.. and it comes right off before I taxi. Take some cleaner with you..I use 409glass/surface.. It's tough enough to take light oil off, but not harsh enough to affect your planes finish. You won't get much throw off from a gasser..but there will be some residue in places(I don't miss glow planes at all when it comes to that)..all my electrics do is get dusty..hehe..feather duster cleans them.

I use 2 identical batteries in my plane for Rx and ignition.. 1400mah nicads. These give enough power to fly 4 flights comfortably.. then it's time to charge... AND.... CHECK your batteries with a meter EVERY flight.

This is where electrics and gas part ways.. when you put a battery pack in your Eplane.. you know it's charged..mostly because you either just charged it the night before, or maybe just took it off the charger.. with gas/glow.. the only way to be sure is to USE THOSE CHARGING JACKS TO CHECK VOLTAGE every time..very important.. maybe I'm anal because I use nicads..but I wouldn't have it any other way.. I fly a kit-built(by me)27%Extra300 and I don't take any chances.


I also recomend you call Don's hobbies in Salina, KS.. he was very informative when I was building my plane.. I also bought most of my components there. I haven't talked to them in a while though. Here's a link I found for them with contact info.. http://www.wtp.net/DBEST/dons/dons.html
And...Hanger9 should make your wing and cowling right.. I've had nothing but GREAT experience with them.. they replaced major components on one of my planes for no-charge, with no questions asked to the tune of about $250 worth of stuff..of which some was justified.. and some they just said..we'll send it anyways just in case.. great company.. you can't go wrong with them.

Man..I hope there's some useful info here.. sorry so long.. do research everything I've said here.. it's always best for second and third opinions... and good luck.. the big planes are a real kick in the pants.. Its just not as easy for some to enjoy them as much, as it is a bit more work.
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Old Aug 03, 2008, 06:02 AM
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I am also new to gas , is my MPI unit that has the switch , chargeing jack ect , is the switch that turns on the power also the "kill switch "?
ALso --throttle set up , do I need to remove the spring on the existing throttlr and add a normal rc unit ?
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Old Aug 03, 2008, 10:53 AM
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Quote:
Originally Posted by Ldm
I am also new to gas , is my MPI unit that has the switch , chargeing jack ect , is the switch that turns on the power also the "kill switch "?
ALso --throttle set up , do I need to remove the spring on the existing throttlr and add a normal rc unit ?
---is the switch that turns on the power also the "kill switch "?
---It is actually another way of killing the engine of course.. main thing I use the igintion switch for is simply turning the ignition on and off.. you don't want to leave that ignition on if your not running your engine.. but I kill the engine from the Tx after taxiing my plane back..and I don't taxi directly towards myself or anyone else.. just a safety thing. When those engine ignitions are armed it doesn't take much effort to start them when conditions are right..I've not heard of anyone being hurt from leaving the ignition on.. but ..there's still a spark generated from the module if the sensors pass each other simply turning the prop.. it takes nothing to get a spark on those ignitions..and it's still thousands of volts to that plug.. just turn that plane off and save that power for flight.

---throttle set up , do I need to remove the spring on the existing throttlr and add a normal rc unit?
I'm not quite sure your meaning on a "normal RC unit".. I am trying to be basic.. basic says no springs.. just a nice sturdy pushrod from a good reliable servo..and it doesnt need to be 100oz's of torque..just make sure your throttle is mechanically smooth from the engine and your pushrod is routed smoothly and the throws are correct to alleviate binding.

There is another point on the choking mechanism that might want to be addressed also.. the engines I've seen have a choke that you operate before starting.. I usually have to use mine.. unless I'm flying back to back flights.. After arming the ignition.. you apply the choke.. flip the prop just like your starting it.. and when you get ONE POP.. it's time.. disapply the choke and get ready for starting.. and at that point they will..
I use a small lever tool that reaches through a small hole in my cowling.. I just reach in with my lever tool(I made it, simple simple),, activate choke...flip prop ..when get my POP..I can quickly reach in and deactivate choke(you don't want to wait too long after the pop as everything will cool off again..if you can crank it 15-30 seconds after choke your OK).. that is simple basic choke stuff..
You can put a servo on the choke and use an open channel.. but in my case.. it's a 50cc plane.. no biggie.. I did take alot of measures to get my plane under 15lbs.. and it wasn't to add stuff... it's a pure dream to fly a light plane.. so that's pretty basic huh..
PS.. I do most of the time choke the engine and crank it through 5 or 10 times WITH IGNITION OFF.. then turn the ignition on and proceed with stuff.. this gets fuel into the system immediately.. just don't hand crank it with ignition on.. it will probably tell you it's on with a KICK<< and hopefully that's all.. I've had kick-backs on my chicken-stick that would have broke my fingers..mostly glow.. but it has happened.. just be ready for anything.
All in all it's very easy to run the engines.. it's just a matter of getting a comfortable safe routine.. and that's a bit different for everyone.
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Old Aug 03, 2008, 05:22 PM
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Thanks for all the information. This is extremely helpful. I have learned that there is just as much to learn on the ground, or more, than there is in the air!!

I am assuming that a chicken stick is somehting that lets you turn the prop over without using ones hand....This sounds like a good idea indeed.

Here are a few pictures of the plane and engine I will be using. It will be a few weeks before I am ready to fly as I am working in Switzerland quite a lot and am not here on the ground in the US as much as I would like.

I hope that Hangar 9 makes good. I've probably mail ordered 15 planes and I've never had as many issues as on this one from the shipping. The gas tank mount had also snapped free internally and was bouncing around inside the fuse making lots of little marks on the skin. Everything ironed out and the gas tank mount epoxied right back in. Only thing that still needs replacement is the cowl. We shall see.

Here are the pics and I will keep adding as I go.

Thanks for the advice.

dan
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Old Aug 03, 2008, 06:10 PM
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First Gasser

A few other tips if I may...

Go the extra mile on real secure battery mounting. DO use foam or other suspension to soft-mount to reduce vibration.

Use blue (not permanent) locktite on engine mounting.

DO lock ALL the electrical connections, or change the power lead connections over to Ultra Deans plugs. Do anchor all the wires every few inches so everything is tight and clean.

If you have to put the Ignition Battery up in the cowl space to balance, be concious of cooling and vibration... make it strong and keep it away from the hot parts of the engine.

It's always best to isolate your ignition wiring from your control system wiring. Run the two systems on opposite sides of the airframe if the Ignition system is inside the fuse.

Balance your prop(s).

RANGE CHECK.

After your first flight... take off the canopy and cowl.... check all your mounting and connections, fuel system, etc. Be patient, check things out carefully. Put a wrench on every screw and bolt. Assume you are an idiot...

Re-Torque the prop bolts after every flight for the first 3-4 flights. They will come loose on wood props as they seat and experience vibration. Use locktite on the spinner bolt... very time.

First flight, avoid real snappy stunts like blenders and hard snaps.

Check your fight and ignition batteries before every flight. Get an eight-ball or other tester.

Cooling air... exit area should be 3 times entrance area. Check your head temperature immediatly after landing on fiirst flights. It will be hot, but you should be able to touch the cooling fins on the head without getting burned. If you have a IR temp meter, look for temps below 200F.

Do use a filter on the fuel pump fill line. Keep the system in the plane clean by never filling without filtration.

I'm sure there is way more, but those are the things I had to learn, some of them the hard way. Be safe, be patient, and enjoy the beauty of gas power, it's awesome! You'll find your slimers will get very lonely.
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Old Aug 03, 2008, 06:57 PM
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not to start a debate, but i have never seen anyone use a chicken stick to start a gas engine, even with three bladed props and 150cc engines. nor do i know anyone who has been bitten, and I ran with the IMAC crowd for about ten years.

a few guys used gloves, but the larger majority did not. The larger props of gassers makes the movement across the blade more natural and your hand is out of the arc when the engine fires, nothing like a smaller glo engine. if you do make one, and you are running a wood prop, make sure the surface is soft otherwise you will crack the trailing edge of the prop. but I really wouldn't worry about it. compared to glow engines, gassers are very simple and reliable - once you fly gas, you will never look at glow engines the same...
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Old Aug 03, 2008, 07:42 PM
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Ditto Koppter... hand start is safe. Gassers are slow and easy. The natural flip is easy to keep clear. Just fingers on the face of the prop, not on the trailing edge. Never have seen anyone use a stick.
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Old Aug 03, 2008, 08:38 PM
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Quote:
Originally Posted by koppterX
not to start a debate, but i have never seen anyone use a chicken stick to start a gas engine, even with three bladed props and 150cc engines. nor do i know anyone who has been bitten, and I ran with the IMAC crowd for about ten years.

a few guys used gloves, but the larger majority did not. The larger props of gassers makes the movement across the blade more natural and your hand is out of the arc when the engine fires, nothing like a smaller glo engine. if you do make one, and you are running a wood prop, make sure the surface is soft otherwise you will crack the trailing edge of the prop. but I really wouldn't worry about it. compared to glow engines, gassers are very simple and reliable - once you fly gas, you will never look at glow engines the same...
That's pretty good there... Budlite(my favorite beer) commercials have what they call "Real Men of Genious"..
There's an idea for them..
"Mr. "I can start my plane without a chicken stick" guy". ....
I think they should all be in that hall of fame..
Then the next segment...
"Mr"I started my plane and cut my finger off"guy"
I'll take a pic of the .40 cents of material I used to make a safe stick and post it...
You all can decide whatever chances you want to take.. I'll even send you guys some... free. I've given them out around Xmas, with custom stickers.. personalized chicken-sticks you might say.. and my friends use them....

And.. not to start a debate here either..but.... how about sharing some nice positive stuff.. this person is NEW to this..with no experience running an engine..... and I can't say I'm not pretty surprised that someone is actually saying they've never seen someone using a chicken stick... come on out and fly with me.. and you'll see someone using a chicken stick... I've gotten used to it after having a tempremental Moki that I've since tamed.. I got secure with it and haven't looked back... gas or large glow.. I use it on all.
I also happen to be a guitar player.. and am very very careful with my fingers..and I run a large printing press for a living that can be very dangerous if your awareness isn't up.... SO..CONSIDER ME AWARE!!
And you all can decide if you like the stick or not.
It's alright guys... just a little vent there...I feel better.
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Old Aug 03, 2008, 09:11 PM
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Hi guys for something linke this I would be using a smartfly "sport" reg and expander system. In this package you get a sport regulator that would alow you to keep the model light using 2x2s lipos or lithium manganese batteries such as duralights. the kit also includes a fibre optic kill switch that is operated from your transmitter with a built in failsafe so in the event of a loss of power themotor will automatically shut down. There is also a Battshare system that hunts beteen which ever battery has the highest voltage therebuy giving you a reliable battery backer. You will also need to run either a 4 cell ignition pack of around 2500 mah or a 1 cell lipo, The imac guys have been experimenting with using this on a DL 50 to good effect. best of all the sport system from Smartfly is only $330 Aussie dollars. Not exactly a huge investment considering the cost of your model and motor.
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Old Aug 03, 2008, 09:12 PM
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so what you are saying is experience be darned, i do it this way and therefore, so should you. good for you, but don't condemn the efforts of others - and certainly don't make the insinuation that I or anyone like me is a Bud Light (note spelling) idiot. The guy is new, so let's keep him on this side of what is common practice. thank you for the invite, but I've been to Clovis, and unless I am passing through on my way to Yosemite, there ain't much reason for me to be there....
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Old Aug 03, 2008, 09:15 PM
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I also agree a chicken stick is bad news on big gass engines, I set my prop on compression at 2 o'clock and use a heavily padded riggers glove that has padding on both front and back andremember when starting to follow through right to left. thats it really, I have done more damage to cowls with a chicken stick than I have been bitten buy a prop and I've been doing this for 28 years.....
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