njmheli

Hi Chorner.

Many thanks for your comments,the P-47 is the H9 30cc ARF ( now not produced anymore )..........she has a OSGT55 up front and weighs in at 26Lbs.

Regards Nick (UK).

Forgot to ask................how's your build going..?

njmheli

Hi Eric.

All the details of my build........so far and set up are posted in this thread,but see below for some answers to your questions.

Rx used is AR 12200 Cockpit...............great Rx,6 servo door sequencer built in ( easy to set up,once you have got your head around it !!! )....main disadvantage is that with every thing bolted on,can't see the LCD twin screens,plus it will spend all of it's life up-side down.I did send it back to Germany for the software up-date and also asked the question about an additional "screen" to see all............No go on the additional screen,as would involve "new hardware ",fantastic service from "Powerbox Germany" and sent back with some sweets (candy in the US ) too !!!!

I will always over servo my aircraft,in the Corsair,all the control spektrum A6030 servos,throttle spektrum DS821servo,gear doors 4 x A7020 MG servos:.

Batteries : Rx powered by 2 x 3650mAh 2S packs
Ignition powered by 1 x 2500mAh 2S pack
U/C powered by 1 x 2150mAh 2S pack
Lights powered by 1 x 1050mAh1s pack.

The Rx and Ign packs are housed in a "batt compartment" built right into the nose,on the L/H side as you look into the fuzz from underneath ( can see the Rx EC3 cables running into the compartment ).
U/C and lighting packs are on the c of g position in the side of the fuzz on a platform,with velcro straps ( just behind the Port elevator servo ).

The servo with the "white arm" ( extra strong servo arms,from Dubro ),is the rudder / tail wheel steering servo...............I tend to use 30LB " breaking strain" fishing line ( plastic coated steel wire ) on all my pull-pull rudder lines,it is much thinner and the items you see "crossed" are the anchor swivels for the tail wheel steering lines.

I use "screwed ball-ends" on the connection to the "tiller" on the tail wheel,with the "fishing-line" just looped around the neck on the ball-ends,then crimped and sleeved.....all the adjustment for the steering,is then done at the "swivels" at the servo.

Hope that the above helps you...?

Regards.....................Nick (UK).

Mein Duff

Nick...many thanks for the detailed info.. this really helps steer me in the right direction especially with the battery packs needed and servo info.
I believe the 2S are Lipo batteries ? excuse my ignorance...I've been using NmHi only for years.out of fear of fires and exploding etc.....I guess the weight saving makes 2S more practical.
I also bought a set of Lipos for a biplane last year but then had to buy a voltage converter to lower the current for 4.8 volt servos which then added more weight again so I was back to the original weight of my NmHi basically....
I imagine your servos are digital ?...haven't read up on them yet...and are digital servos really needed?
Thanks again for posting, Eric

njmheli

Hi Eric.
Batteries are Lipo's,servos are digital...being able to produce more torque,quicker response and better holding power against the in flight forces etc.
The Cockpit Rx will take various types of batteries and can be adjusted for voltage output to the servos...either 6volts or 7.4 volts.All the servos I mentioned are rated up to 6volts.Note : any Spekturm Rx's should only be supplied with a min of 6 volts....NEVER use 4.8 volts....... Very hi risk and probably will occur a "brown-out" !!!!?

At the end of the day,it's whatever you feel best with and have used in your aircraft that works for you....Lots of info on this thread and everybody is willing to help you out with their indervidual ideas and ways of doing things....also any problems encountered along the way and there had been a few !!!!

IMO for this build,I think the engine choice is an important one to start on and work things out from there,as said lots of info on engine choice and achieved weights, c of g's etc.....

Definately fit TWO servos for the flaps........quite a strain IMO for one,even a high torque servo.

Hope that your Corsair arrives ok,enjoy your build !!!!

Regards Nick(UK).

chorner

Nick, you could eliminate 2 of those smaller batteries and you'd be perfectly fine. That's a hell of a lot of batteries to charge to go out flying considering the bloody thing is gas powered, it's twice the battery maintenance ontop of engine maintenance! All you need are the two RX batteries, and single ignition battery. The lights takes next to no power draw, and the retracts I was quoted as being able to obtain a good 30 cycles on 2000mah. You'd never use anywhere near 30 cycles even over the course of 4 flights.

Heck you'd be OK with one 4,000mah RX shared battery with the setup on this plane. Be quite the different story on a giant scale 3D plane with all high torque servos: 4x aileron servos, 2x elevators, and a super high torque rudder servo. Even still a single 4,000mah battery would last you at least 3 8-10 minute flights.

Mein Duff

I've pretty much settled on the G-62...lots of local help if I need it and price / performance / reliability sounds like a solid way to start. Plus I can use this engine with a Schlundt 2.81 reduction unit for a 1/3 Camel later on.
Enjoying the input on batteries...I agree with Chorner with the "less battery maintenance the better" motto....having two packs though does sound like a good idea especially if one conks out.
BUT: in over 20 yrs flying, I have never had a battery die on me in the air...after three yrs. they are recycled...no black wire disease please.
Always have a "volt watch" thingy plugged in and never fly in the yellow zone.

njmheli

Hi Chorner.

It's just my preference to have those batteries and set-up that way.............I need some weight in the nose,so the extra battery for the ignition works with that. By the time everybody is finished "kitting" this bird out,there is quite alot of $'s and £'s up in the air.As said before,I prefer to over servo my control surfaces and make sure that there is plenty of power available for 20Kg servos @ 6 volts...........

No massive problem to charge the batteries,can be done all at once on a "multi-charger"...................

I like the fact that all the electrical systems are separate,nothing "shared",therefore if there was to be a "fault" in one,it would not cause a problem with the other systems.The very last thing I would want to do is share the power for the Rx,especially as it is designed to have redundancy built in via the two separate power supplies,and tapping of those would certainly make one open to a fault and render the redundancy useless !!!

All the U/C control / ignition / lighting boards should have their own built in "short-protection" devices..............but if they should fail,having shared the power source,you could end up with a battery melt-down up in the air and you wouldn't know about it until you either saw smoke or loss of control !!!

On my all electric models,I never use the BEC function on the ESC....................ALWAYS powering the RX from a separate battery,along with keeping the retracts on their own battery.Should the ESC fail,lets be honest here,they do work hard,with all those amps going through them,you will possible lose all your RX power and that will end a good days flying !!!!

As said in the begining,lots of monies tied up here,so why not make the bird as safe as you can,with redundancy where you can and make good use of the weight required and it's distribution in the airframe.................

Regards.....................Nick (UK)

How's your build going..................?

Ted62

My Feedback: (2)

I, too, use 2 RX batteries for redundancy. The "Smart-Fly" power distribution system makes it really easy to do with only one small switch needed to turn everything on. I only power the RX with my 2 LiPo's - everything else has its own power supply (gear doors, nav lights, glo-driver, pilot). The plane has been a real work in progress and Nick has been super helpful getting to this stage (tnx, Nick!). Now that the ground run has been completed, it's finally ready for the maiden which will be a week from tomorrow - wx permitting. The 7-77 idles less than 1000 with the glo-driver and sounds wonderful. Plane weighed-in at 31.5 pounds today.

chorner

Hey Nick,

Fair enough! I have a 200watt 4x charger, but to me adding more complexity actually increases the chances of something going wrong. Just my 2 cents anyhow, and I definitely agree on the idea of doing your best to protect the kind of $'s and £'s invested though. I just think going that route could and usually does end up causing more problems than it fixes, not to mention having to think of all the additional check points. "Is my 2000mah battery charged, is my 3250 charged, is my 2150 charged is my 1000 charged... whups I put my 2000mah on 1000mah on the charger, and forgot about the 3rd battery and oops, how many MAH was drawn from this battery in this length a flight, versus that battery" It can get a bit "silly".

Just my opinion of course, we all have our own ways but I'd hate to see all those extra points of redundancy end up causing an issue!

Mein Duff

"Whatever works for you is best, as long as it works !" ...each to his own and probably based on lots of personal experience.....I am all for simplicity but redundancy makes sense to a degree.
Enjoying this exchange from a newbie standpoint..
I received my Corsair Saturday and have already spent two hours repairing vertical Stab. after it fell out of the box while standing vertical...nice way to start !
I am planning on converting mine to the Birdcage version and was wondering if anybody has any detailed drawing or pics of that area of how the original was designed to function?
Looking at some of the pics in a book I have, the angles don't make sense to me....

njmheli

Hi All.

Have just finished my final installation of the 84 on my Corsair,all good so far !!! Just a couple of finishing items to do on the wings and to replace those "plug connections" for the lights...............too fragile IMO..?

Decals to do, final spray on the cowl and lastly the c of g...............so pretty near now,been a long time on this "project" ............

See photos below...........

Hope all going well with the builds etc............

Regards.......................Nick (UK).

SWORDSN

My Feedback: (13)

Neat install

youngguy

My Feedback: (7)

A short up date on my Corsair and a caution for all those who are in the process of assembling their Kits. After 1/2 dozen flights on mine, the rod on the compression strut on the tail wheel unit came undone and was lost in flight. There are two things that everyone may want to consider. Lock Tite the retaining studs on each side of the rod and change the compression spring to one that is softer than the original. Mine was so stiff that it allowed very little if any movement.
I still consider this to be a fine model with very good flight characteristics. The landings are very well mannered using full flap. Rolls could be faster and I will be working to speed them up. Really enjoying the few flights I have had on this bird.

chorner

For those looking for ways to balance this plane, or any other giant scale plane here's the most accurate and "stress free" way to do it. It also happens to be the way full scale planes are balanced. I tried the Vanessa rig and it works well enough but I'm not a fan of hanging these planes by string with all the weight on small points of balsa etc.

You'll need:
- 1 to 3 scales (one for each wheel optimally)
- tape measure
- box or something to prop the tailwheel up so the horizontal stab is level

Step 1)
draw a line on the floor at the tip of the spinner or push the plane up against the wall so the spinner is touching the wall. This is your measuring point. If using 3 scales, place scales under each wheel and set tail level. If less than3 scales make sure to get the height of your scale and add that same height under the wheels without a scale. The idea is to keep things as level as possible, but a little off won't be an issue.

2) get the weights at each wheel. Now measure from the measuring point to directly under the centre of the axles on all the wheels. Keep track of each separate wheels measurements.

3) multiply the weight x distance recorded for each wheel. This is the "moment". Now add all 3 "moments" (units doesn't matter) together for a total. Add all three weights together. Divide the total moments by the total weight. This will be your current CG point back from your measuring point on the plane. Compare this to the correct CG listed for the plane from the LE of the wing. Add weight where needed and recheck.

My favourite method and by far the most accurate.

Greg Wright

My Feedback: (6)

This is a new product from Xicoy to set up your C.G.

https://www.youtube.com/watch?v=tfXTyz8w7JY

chorner

Greg, that's an awesome product. Calculates the method posted above in real-time, with 3 included scales; never knew that existed! I will have to buy one for sure now. Thanks for posting that. I was actually going to post how to calculate where to add weight/how much for people if there was a response to this method, but I see the CG machine also tells you this in real-time. Awesome

http://www.ultimate-jets.net/product...tal-cg-machine

Link to the product page. Better than buying 3 scales plus building a Vanessa rig only to find out it sucks and is way off compared to this method like I did haha

Greg Wright

My Feedback: (6)

I just placed my order for one.

Zeeb

My Feedback: (41)

The Xicoy machine is just a tiny version of the way full scale airplanes are done and it's got the advantage of doing all the math for you. When I used to do full scales you had to level them on a provided datum line and weigh each of the three gears. Then measure from the forward datum which was usually the firewall on singles or the first cabin bulkhead on multis and do all the math. I always had to put out my A&P Airframe Manual to figure out how to do it.... lol

Any way, this thing is really well made but comes in a small cardboard box so you may want to consider something to put it in while traveling. I saw a post of one in a Pelican case over on the Jet Forum so that's what I bought for mine.

chorner

Zeeb that's pretty cool. Wonder why the differences in measurement points, or maybe just that they were good squared up points of reference or something? From what I understand (but having never done a full scale of course!) you can pick and reference point as your datum and the math will work out the same - you can test this on the model as long as your measurements are all spot on

So the Xicoy is worth it then and well built? I'd like to buy one but having just gone to all the trouble of making my own setup for this I'm hesitant to buy something else now. Though if this is well built it will last and be used many times over

ForcesR

During aircraft weight & balance we always picked a reference datum point 10 to 20 inches out from the front of the nose as indicated in the attachment.

Roger

Zeeb

My Feedback: (41)

Yes I think the unit is well built, the little scales are nicely made and while there's nothing fancy about the control unit its on a par with a turbine GSU unit.

As for the datum; yes you could put that anywhere as you suggested and ForcesR mentioned. However in the USA, father Federales (the FAA) wants it done according the particular A/C maintenance manual. If no datum's are specified then you can pick your own.

Now while the rig you just made will do the job, this is much cleaner and I don't have issues putting one of my turbines on the setup. My Shockwave was done the old fashioned way by friends who put it together so I'll be interesting to check using the Xicoy. I can do that alone with the Xicoy where other methods would be difficult with a model that's 102" long and weighes about 48lbs. dry, by yourself.

camss69

My Feedback: (46)

I have an Excel spreadsheet that I use for calculating CG, it was given to me by an old timer friend of mine. You level the airplane, weigh it at all three gear, add in the meausrements to the datum and it does the rest. The nice thing about it is you can pick a point on the airplane, add or remove weight and it will calculate where the CG will move to. As long as you have a scale it's basically free and you know exactly what adding or removing weight from any place on the plane will do to your CG.

Zeeb

My Feedback: (41)

Well then may I humbly suggest you keep your setup, no one is going to force you to buy the Xicoy....

DrScoles

My Feedback: (18)

Nick, do you have to cut the cowl to get that bad boy in?

Zeeb

My Feedback: (41)

Not Nick but I'll tell you that the boys in St George who put mine together with the FG84 didn't have to cut the cowl and probably would not have had anywhere near as much effort if it had the stock exhaust. But mine has the Keleo exhaust ring and the Ray English mods on the engine.

Have fun Mike.....