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Old Jul 04, 2008, 10:17 PM
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Very Nice!
I'm going to install that tailwheel in my TF P-51 ARF. I like the way you mounted it and may borrow that design

Mark
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Old Jul 05, 2008, 02:15 AM
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Sydney, Australia
Joined Jun 2006
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Thanks very much everyone. It doesn't look like much thought went into it actually because it is relatively simple. I just hope it works though. The challenge will be the door mechanism and building a new rear fuselage section since I now can't use the solid balsa block as called for in the plans.

Eric, where is Embry-Riddle?
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Last edited by Gree; Jul 05, 2008 at 02:38 AM.
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Old Jul 05, 2008, 05:25 AM
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United States, MT, Butte
Joined Mar 2007
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Embry-Riddle

There are two universities in the US, one in Florida and one in Arizona. I'm going here to the one in Prescott, Arizona, for Aerospace Engineering. They are supposed to be one of the best aeronautical universities, so, I guess I'll just find out.

Eric
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Old Jul 05, 2008, 10:38 AM
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Ah I see - well good luck with your studies. That chick on their web page should be paying more attention to what she is flying I think! Bit low t be looking backwards!
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Old Jul 05, 2008, 12:00 PM
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Haha, yeah, thanks. Good luck with your P47, its lookin good!
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Old Jul 08, 2008, 10:20 AM
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Sydney, Australia
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Motor and ESC Decision Finally Made!

Well tonight I bit the bullet and went with Corsair 29's suggestion of a Turnigy motor. I also got their 100AMP ESC and programming card, along with a good UBEC and motor mount for under USD$200. I am pretty happy with that. The ESC may be overkill but I want something I know will be on the safe side!

This was one of the hardest decisions for me as I am still relatively confused by all those amps and volts, but it looked like a good deal based on a lot of people's suggestions of comparable motors.

We'll see I guess!

Stats for items at Hobbycity as listed below for those interested (as you can see there is a bit of a Turnigy theme going on)...


Turnigy 50-65C 320Kv Outrunner



TURNIGY Sentilon100A HV 2-12S Speed Controller



TURNIGY BESC Programming Card



TURNIGY 5-7.5A (8~42v) HV UBEC for Lipoly



HXT Alloy Composite Firewall Mount (25/30mm)



For better or worse its paid for now!!!
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Last edited by Gree; Jul 08, 2008 at 10:25 AM.
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Old Jul 11, 2008, 10:55 PM
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Joined Sep 2007
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Gree

Iíve been reading your posts with some interest, very nice/thorough work! Iíve just finished building/converting a TF P-47 to electric. As soon as they finish paving the runways at our field Iíll fly it. For my P-47, (which is the Razorback version) I made the canopy/cockpit removable (held on with magnets) for easy access to the batteries as you can see from the pics. Iíve glassed it using the water-based Polycrylic method and my ready to fly weight is 10Lbs-2oz. When I made the battery box, I made it so I could move the batteries around quite a bit as needed for balancing. The batteries ended up right behind the firewall for perfect balance.

The power for my P-47 is very similar to yours, as I went with the Turnigy 50-65B-350 motor, an 80 amp ESC, 3300 6S1P batteries and a 14.5x11 3-blade prop. With this setup MotoCalc (which I HIGHLY recommend) says Iíll have just over 100 watts/pound. It was probably a good choice on your part to go with the 100 amp HV ESC like you did, that way if you need to upgrade to 8S, you can use the same ESC. Good thinking! If I find that 6S isnít enough, Iíll need a new ESC.

Iíve had pretty good luck with the Turnigy motors. I think their motors are slightly less efficient then the big names, but you canít beat the price. The only problems Iíve ever had with Hobby Cityís motors/ESC were always my fault (so far).

In the third picture, I have the guns 'firing' in sequence but the camera didn't pick that up.

I look forward to seeing your flight reports!!

Russ
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Old Jul 14, 2008, 05:23 AM
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Hi Russ,

Thanks for your input. I remember you giving me some advice about batteries etc in another thread. I thought long and hard about different motor/battery options and so many people on the forum have been a fantastic help.

In the end you have to make a decision though, and boy am I glad to hear some positive feedback on the decision I ended up making! So thanks for that - greatly appreciated!

I tried to use Motocalc, and it kept telling me my plane would not fly with the information I put in there, so i am not sure what I was doing wrong! You have made me feel confident that it will indeed fly with what I have bought for it!

I think I am going to go for 8s, but it will be a while before I buy the batteries. I want to run a four blade prop however, so I think I will have to try learn how to use that Motocalc before the 30 day trial period finishes up!


Construction has slowed a lot lately as I am a bit busier these days, and I am spending some time thinking things through a bit more as I am up to doing a lot of custom work that varies from the kit - such as the tailwheel etc.

I am debating right now whether to do a hidden elevator linkage and pull-pull rudder system or just to go with the stock setup...

hmmmmm....

Anyway thanks again for the post, it came just at the right time to give me a bit of confidence!
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Old Jul 14, 2008, 05:23 PM
TRP
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United States, CA, Morgan Hill
Joined Jun 2002
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Hey Russ,

She looks great! Kind of reminds me of my old TF P47.

Let us know how she flies. How'd you get it to balance with the batteries that far back? I had to put mine through the firewall.

T
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Old Jul 15, 2008, 10:19 AM
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Advice Needed! Pull-pull Set Up

I am in the middle of setting up my pull-pull system for the steering on the tail wheel, and have hit a dilemma, and I would appreciate some advice from those with experience with these types of set ups.

I am using a Dubro pull-pull system. I want to run both the rudder and the tailwheel steering from one servo to simplify everything and keep weight down.

The trouble is when I run the cable from the tail wheel to the servo, a few formers get in the way, as you can see in the pics below.

The solution I was thinking of involves drilling a hole in the former directly behind the servo (as indicated in my pics) so as to pull the wire out a little to clear the other formers. I would use a metal eyelet (since the wire is coated in nylon - should be relatively smooth and 'slidey') to reinforce the hole and to give the cable something to slide on. The type you see on canvas or women's bodices etc (hmmm, what was I saying, sorry got distracted...), oh yeah - like this one....




The only problem I see is that this will increase the friction in the system and put more load on the servo... But how much extra friction will there be?

Since I have no experience with this type of thing, I was wondering if anyone had done something similar before, and if any friction added in the movement would really be noticeable or not. I thought of making some kind of small pulley system but that is getting too complicated.



I would really appreciate ideas or comments on my idea if anyone has any out there! Thanks
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Last edited by Gree; Jul 15, 2008 at 10:24 AM.
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Old Jul 15, 2008, 12:17 PM
Fly allot, Crash allot, next?
United States, CA, Corona
Joined Feb 2006
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Gree,

I just want you to know that I am using Turnigy motors and the 100 amp ESCs and in the past I have nothing but good things to say. I even plan on ordering more for future builds. However, I have found something unusual with the last 100 amp ESC that I bought. I am using it on the Thunder Tiger Sea Fury with an Eflite 110 motor. Anyway please test it out on the ground before using it on your maiden flight.

Here is what mine does, rapid advancement of the throttle seems to cause the ESC to send the wrong messages to the motor, the motor squeels and looses power. At first I thought it was a loose prop, nope, I was able to duplicate the problem on a test stand. I re-progammed the ESC with the card hoping to clear up the problem, but, it happened again last week. I was attempting a go around. I slammed the throttle stick forward and was forced to land long. Perhaps there is a communication problem with just my setup of the Turnigy 100amp ESC and the Eflite motor as I have another setup with the same ESC and an Hacker 60 motor and it works perfect.

Nothing to be overly alarmed about, but just to be sure, check it out. I can't wait to read the flight reports on all the P-47s, it's the only plane that I haven't done yet.

Al
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Old Jul 15, 2008, 01:50 PM
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Ted,

Mine does look quite a bit like yours Ė although you got the grey going up on the bottom of the cowl (like it should), I didnít. Iíve always liked the early green/grey Razorback versions of the 8th Air Force instead of the later silver bubbletop versions.

It sure sucks that you had the fires Ė I probably would have sold it just like you did. Iíve had an ESC start on fire also, but that was on the bench after it worked really weird in flight. I got lucky. It turns out that a 60 amp ESC doesnít like 70 amps; who knew? I probably should have purchased MotoCalc before I flew that plane.

Not sure how I got the CG right with the batteries further back that you did, as mine came in at 10.2 pounds compared to your 10.5? Didnít you have air retracts? Maybe they add more weight to the rear than the mechanical retracts I used? I did use the cheaper (read heavier) motor and batteries from Hobby City Ė that may be some of it.

I took the plane out and taxied it around my driveway and bent the mechanical retracts (wonít use those again, they are very weak) so Iíve been waiting for the contractors to finish paving the 850í runways at the field before I take her up. Iíd like to have 15-20 flights on the P-47 before I try my TF P-40 (which has been ready for almost a year now). I heard that the P-47 was much easier to fly, so I want to get proficient with the P-47 before I try the P-40 Ė need more flying experience in general as I still crash a lot. Already 4 pretty bad crashed this year.
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Old Jul 16, 2008, 03:51 AM
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Sydney, Australia
Joined Jun 2006
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Thanks very much Scalefan for the advice - I hope mine doesn't do that! I'll end it back if it does. I had a speed control that did that, and also stuttered at low throttle, so I know what you mean - funny thing was it was an expensive model. I sent it back to where I bought it and the guys says he tested it and it was perfect so he sent it back.

Guess what? Put it in another model and low and behold it does the same thing! My cheap ebay Tower Pro ESCs on the other hand, never had one problem!


So no one has any advice about my pull-pull system problem?
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Last edited by Gree; Dec 31, 2010 at 04:47 AM.
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Old Jul 16, 2008, 10:17 AM
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Brentwood, California
Joined Jul 2007
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Gree I think you will be fine with the wire guide idea..
I would just make sure you have a good metal gear servo
with at least 100 oz torque ..like a hi tec 645 MG
then you will have no worries

Ron
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Old Jul 17, 2008, 06:37 PM
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Thanks Ron. Good to hear you think it will work OK. I am going to keep thinking about it for a little while because I am worried about friction wearing the nylon of the wire over time - but at the moment it will remain my plan of action.

More updates soon I hope - time to work on it is scarce these days
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