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        Discussion Topflite P-40 Red box edition

#1 screilly Jan 21, 2013 01:22 PM

Topflite P-40 Red box edition
Anybody familiar with this plane. It was 40 - 60 size. They are about 6 -7 pounds? I believe they were out of production quite a while ago ... maybe early - mid 90's. I was interested in the flight characteristics and maybe some suggestions if you have ever flown this particular plane?

I have two of them that were built by someone in the 80's or 90's? It looks like they were going to try to fly them and changed their mind an used them as static display only. The glue was very brittle and not air-worthy on the first one, ... I have not checked the second plane but I expect the same on it too. The glue-joints at the main structural components were compromised at almost every point of connection. This made easy work of dis-assembly. Once apart, ... I went through with e-poxy and CA glue where it was possible.

I removed the 5 original standard servos thoughout the entire plane and also the bell-crank assemblies at the ailerons & flapps. Originally it had one servo for the flapps and one for the ailerons with the bell-crank assemblies, ... plus one servo for each of the other elevator. throttle, and rudder.

I took out all bell-crank hardware, push-rods, etc and installed individual servos for each control surface. I used the HS-81 at every surface. I mounted the new servos close to the control surface so they would have very short push-rods. I made access panels in the wing and at the rear fuselodge area to mount the new servos securely. I think they will be a good choice but would like some opinions on that if anyone has a suggestion?

The engine he installed is the K&B 61from that same time period, ... It was run and tested but has never been fully broke -in. Probably 1 or 2 tanksof fuel? The piston and combustion chamber is all clean as new. The piston has the raised beam on top. It should pull that pane but also wondering if there is any suggestions or comments on the engine.

The plane is 6lb - 10oz with everything but the fuel. I wanted to balance it and go fly but wanted to be very careful with the throw adjustments and C/G. I'm interested If you may have advice in the set-up, ... I wanted to try Dual rates on the control surfaces. Any input is welcome.

#2 Ldm Jan 22, 2013 05:21 AM

Have to leave home for work , running late .
I built the original and have one new in box .
Will comment tonight .
The good news is its a great flying plane , keep it as light as possible in your "re-assembly"
Google and you will see some eletric conversion , great plane more stable then the kit version of the Gold Edition of the P40

#3 screilly Jan 23, 2013 12:25 AM

The firt one that i'm working on has flapps and no retracts. The other one, ... which I have not reallylooked at has retracts and no flaps. The CG is a big concern. They came fully assembled and one original box. I have a set of plans but I don't know if they are for the one I'm working on or the other one? Maybe they were two of the exact same kit? The plans I have do show several differnt schemes of the original full scale version of the P-40. I read a little bit of the plans and they do state that you can sheet the plane in balsa or cover it in monocote. These are both fully sheeeted in balsa .

#4 screilly Jan 23, 2013 04:20 PM

I had a 6o -90 size seafury that weighed about 8.5 lbs. it balanced good and flew decent. I never flew the P-40 so I wanted a little advice with c/g and also the throws on control surfaces. The elevator is 5/8 " on the plans but that is from full up to full down according to the drawing. I would think that would be 5/8 up from neutral and 5/8 down from neutral? The Ailerons show 1/2" full up to full down .... I would think 1/2" up from neutral and 1/2" down from Neutral?

#5 Ldm Jan 24, 2013 01:02 AM

Home on Thursday and will get you the settings .
As far as CG I use the 25% of mac rule, if you need details on that let me know

#6 screilly Jan 24, 2013 09:37 AM

I would be interested in your thoughts on the c/g .. I've heard several different ways over the years, ... and some of which has been bad advice. I've been doing mine upside down and empty fuel tank.

#7 turbonut Jan 24, 2013 11:19 AM

Low wing = upside down and tank empty..plane sits level...not nose down or up...

#8 screilly Jan 24, 2013 01:29 PM

I've been doing it upside down, tank empty, and just al ittle nose heavy, I had a P47 that was extra nose heavy but it crashed before I could try anythng different. I had a Combat 40 corsair with an electric set up that was slightly nose heavy too, ... but probably too much nose heavy? I'm gonna try it level and see what we get?

#9 Ldm Jan 24, 2013 06:41 PM

Scre , the 25% of mac is proven , its not guessing , urban legend ect , its math .
If you google "how to calculate CG on an RC model you can see the process useing 25% of mac .
Now if you want the "cheat sheet" that does not take wing shape into consideration you simply do the following .
Measure the wing front to back at the line that attaches to the fuse , lets say is 12" leading edge to trailing edge .
25% of mac useing the cheating method (close enought ) =4" from the leading edge .
I can tell you that in the last five years I have maidene about 10 rc planes , everyone a warbird , everyone useing true mac and or cheat method everyone still in my possesion unless I sold them.
I am telling you what was given to me by a very wise rc flyer and its the best advice I ever received

#10 screilly Jan 24, 2013 08:36 PM

Thank you and I will do the same from this point forward. If that works for you ... it will for me too. I asked that before and that is generally what I've practiced too. I have tended to leave a little weight up front of CG but have found that it is not as necessary as some have implied. Tailheavy is another story all together.

#11 Ldm Jan 25, 2013 04:27 AM

No problem , tonight I am home from traveling and I will go to my red box kit and look up anything you need from settings to suggested CG .
In my span of RC I have one problem , I have had an addiction for the P40 lol .
I have or sold or built , the Guillows , TF red box (2) Gold edition , Pica 1/6 , Hobby People ARF , 2 VQ P40 , LX Models 79" P40 (seen in my blog) 2 FMS foam P40ties , so its one plane i am very familar with lol

#12 screilly Jan 26, 2013 07:34 AM

Ldm ... These two are built by someone else and they were never flown, I can tell you that they were not airworthy. the guy thought they would be but he was mistaken' The glue was dis-engaged at every sritical structural point. Evevn the balsa was seperated from the ribs. They do look reakky cool though. I will get some pitures for you and you'll see what I mean. I didn't want to let them stay in this condtion. They just feel like they want to come to life. If They are properly tended to, .. they will be very impressive! It's like they have been waiting for 30 years for this moment.

#13 Ldm Jan 26, 2013 05:05 PM

I opened the box to find the following
airleons 1/2 max
elevator 5/8" max
Flaps 50 degree
CG based on my suggestion of 25% of mac is virtually dead on at the back end of the measurment , almost dead on !! :)

#14 screilly Jan 26, 2013 05:37 PM

Ldm 1/2" from neutral center to the end of travel, ... or from full down to full up travel?
Same question for the elevator .... and the rudder. What is the travel for the rudder

#15 Ldm Jan 26, 2013 05:52 PM

Hi Sci , every movement described was from dead center with the exception of the flaps ,they are are closed position to 50 degree max .
The rudder was not listed at all but I always give my rudder max throw as on any warbird you need good rudder movement

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