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#1 GrahamWilson Feb 27, 2012 03:09 AM

Cessna 400
 
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I am also working on a Cessna 400 I purchased from HobbyKing in Sydney. Opening the box revealed that this is another FMS model with the usual series of very poor and very small black and white photos in the manual for instructions. This really is not good enough and these manufacturers need to get the English Language instruction manuals up to a much higher standard than what they are supplying with their kits now.

When I removed the horizontal stabiliser from the packaging the elevator hinge failed and the elevator just fell off! Great build quality FMS. So I installed pin hinges and inspected all the other foam control surface hinges. They were ok.

Just like the Cessna 350 the 400 Corvallis just bolts together. Just be careful that everything lines up straight and after installing a Spektrum receiver and binding it to my DX8, I thought it would be a good idea to install the optional flaps. This involved cutting the flaps away from the trailing edge of the wings, installing the hinges, control horns, servos and pushrods. Feeding the servo wires through the wing channels available and configuring the flap system on the radio.

I set the C of G exactly as indicated in the manual but the maiden flight proved that this was a little too far aft. So I have been experimenting with the position of balance by taping coins to the cowl. So far I have tried 20 cents and 40 cents and it still needs to be further forward. Most probably needs about 90 cents to get it right.

The Cessna 400 fits easily in the back of my car fully assembled for the trips to and from the field. A big bonus in my opinion.

The maiden flight the Cessna 400 did not leave the ground, after hitting a tuff blade of grass on the runway the rudder servo striped and was totally useless. I replaced this servo with a Turnigy 90s servo that fitted without any problems. The 90s has metal gears and a lot of torque.

The next day the 400 was flying at the field and apart from a rearward C of G it flew very well and the flaps are very effective at slowing the model and allowing steep short field approaches and landings. The model has plenty of power and a good turn of speed. It looks very scale like in the air and it is a lot of fun to fly.

However, after the fourth flight the nose wheel pushrod bent after a fast landing roll out. I have replaced this pushrod with 3mm piano wire. This seems to be working ok at the moment.


Went out flying on Tuesday morning (28/2/12). expeimenting with the C of G location. I found that my 400 flies very well with the C of G set at 60mm from the Leading Edge of the wings.

#2 GrahamWilson May 16, 2012 06:47 PM

There are continuing problems with the fire wall and the nose wheel on this model. After a heavy bouncy landing on the grass the fire wall, which is made from a hard white plastic broke around the mounting points for the nose wheel.

This proved to be very difficult to repair as the epocy and diffent glues I tried would not bond to the plastic. So I have ended up making a aluminum plate that I have bolted to the plastic to effect the repair and keep this model flying.

Yet issues continue with the nose wheel continually bending.

The model now has around 100 flights on it. Still flies very well but I have had to replace the pushrods on the rudder and elevators as a serious flutter was developing.

#3 Andy2No Aug 28, 2012 01:09 PM

Hi Graham,

How does this compare to the ST Model Cessna 350, would you say? I've considered the ST one a few times.

I have the ST Fox EP, and I know someone with the ST Discovery trainer and someone with the ST Beaver. They do tend to under power things. The Beaver seems to have plenty of power but the wing isn't stiff enough, IMHO. The servos are too small for the size, as they are in the Discovery - which is a bit marginal on power. It can be hard to get it off the ground unless the grass is very short. Some skimping on an ARTF or RTF is normal though.

The Fox wing is very flexible but it's a glider, so that's fine. The real thing would be flexible too. I changed the motor in my Fox but I know someone who flies his quite happily with the stock motor and just a cut down prop, which improves it a lot.

How hard would it be to carve more space behind the battery box on the ST Model Cessna 350, for a bigger battery, or to balance a heavier motor?

The fact that the 400 is tail heavy is promising in a way - it would be easier to add more stuff in the nose.

#4 GrahamWilson Aug 28, 2012 04:40 PM

The ST 350 and the 400 are similar. the ST 350 is very under powered out of the box. Mine now has a Turnigy motor and it is by far a better model that the standard version.

Problems with the 400 are the firewall breaking constantly and the nose wheel. The model flies very well on the standard setup.

#5 Andy2No Aug 28, 2012 05:52 PM

Thanks, Graham.

I could change the motor on the ST 350 easily enough, but getting it to balance could be a problem, unless the battery can be set further back.

Maybe I could reinforce the firewall on the 400 and fit a better nose leg instead though. I plan to use 3" wheels for grass on either of them, so it's not going to look perfect anyway. On my Parkzone Trojan, I did a mod I'd read about to strengthen where the nose leg attaches by just setting a block of wood behind that part. It stands out a bit, but I never notice it now.

The 400 is quite a bit heavier, from the specs, but adding a decent motor and a bigger lipo to the 350 would account for some of that. I like the fact that the 400 already has independent aileron servos. I guess adding the flap servos is no real trouble.

How do they compare for wing stiffness and general rigidity?

#6 GrahamWilson Aug 28, 2012 10:27 PM

I have a Park 480 1320Kv (http://www.hobbyking.com/hobbyking/s...r_1320kv_.html) with 45 Amp ESC in my 350. C of G is fine with this motor and it flies well.

I fly off grass in a park and I have not needed to change from the stock wheels.

Best C of G on the 400 is 60mm from the leading Edge of the wing. The 400 you will need two servos and a reverser if you want to use the flaps, the 350 has working flaps out of the box.

Both can be difficult to see against white clouds.

I hope this info helps.

#7 Andy2No Aug 29, 2012 01:28 PM

Thanks, Graham. I was thinking the 350 was balanced correctly with an 1800 3s and the stock motor, so any more weight would make it nose heavy.

The 400 is cheaper, from HobbyKing, but from what I've read, it sounds like quite a bit needs replacing, like the pushrods, and a nose leg that doesn't keep breaking would be better than trying to improve on one that does, I suppose.

I have plenty of motors, and probably have a spare ESC, so upgrading the 350 should be easier.

#8 GrahamWilson Aug 29, 2012 05:36 PM

Quote:

Originally Posted by Andy2No (Post 22584233)
Thanks, Graham. I was thinking the 350 was balanced correctly with an 1800 3s and the stock motor, so any more weight would make it nose heavy.

The 400 is cheaper, from HobbyKing, but from what I've read, it sounds like quite a bit needs replacing, like the pushrods, and a nose leg that doesn't keep breaking would be better than trying to improve on one that does, I suppose.

I have plenty of motors, and probably have a spare ESC, so upgrading the 350 should be easier.

Yes you have a good understanding of the 400. My 350 has 15 grams of lead on the tail. I fly it with 1800 mAh and with my tearing up the sky I get eight minutes with 3.7 volts left in the pack on landing. I like a good buffer on the electrons just in case I have a couple of shocking approaches on final.

#9 Andy2No Aug 29, 2012 08:08 PM

Thanks, Graham. I prefer to balance planes without adding weight, if possible, but I guess it doesn't take a lot on the tail to counteract quite a big change in the nose.

#10 Starmarc Sep 02, 2012 08:03 PM

Hey Guys...

I bought this model.. Flew it for the first time on the weekend and was super impressed.. Like everyone else though I had to put a lot of weight in the nose to fix the CG but my guessing at home turned out to be perfect.. Plane flew amazing.. Hardley needed any trimming and had lots of power.

On my 2nd landing though I broke the firewall.. Seeing this post I see its an issue... To be honest I am not sure how I am going to fix it yet.. I am thinking of replacing the whole nose wheel and putting in new mounts on the firewall above the spots where the broken one were.. I am going to lose the scale looking wheel pant on the nose wheel I think.. I will have to keep you updated with how the repairs go..

#11 GrahamWilson Sep 02, 2012 08:47 PM

Yes Starmarc, the nose wheel / firewall is a big problem. I am not sure I have a perfect solution for you. I have tries a number of things and I now have an aluminium firewall. Still not sure if this is the perfect fix.

I have found the best C of G is 60mm from the leading edge. Also change the pushrods as the factory fitted are just too weak and the control surfaces will flutter.

#12 Starmarc Nov 26, 2012 07:40 PM

Hi Graham..

I found the easiest solution so far I think for the nose wheel. I did fix not long after I messaged you here.. I only just saw your reply. Sorry for not getting back to you..

I don't think this will help you now you have replaced the firewall though.. But what I did was odered this

Dubro part #152 Link below..

http://shop.dubro.com/p/steerable-no...bent-qty-pkg-1

I just screwed the nylon brackets into the firewall under the motor mount.. Its is now super strong and I have had about 100 flights no problem since... Once I found a hobby shop that had the part it took me about 30 mins to fix it..

#13 GrahamWilson Nov 27, 2012 03:01 AM

Quote:

Originally Posted by Starmarc (Post 23371439)
Hi Graham..

I found the easiest solution so far I think for the nose wheel. I did fix not long after I messaged you here.. I only just saw your reply. Sorry for not getting back to you..

I don't think this will help you now you have replaced the firewall though.. But what I did was odered this

Dubro part #152 Link below..

http://shop.dubro.com/p/steerable-no...bent-qty-pkg-1

I just screwed the nylon brackets into the firewall under the motor mount.. Its is now super strong and I have had about 100 flights no problem since... Once I found a hobby shop that had the part it took me about 30 mins to fix it..

I have made an aluminium fire wall and mounted the nose wheel to it. It is now much more durable but not bullet proof.

#14 Starmarc Nov 29, 2012 05:01 PM

Is it still flying Graham..?

#15 GrahamWilson Nov 29, 2012 09:18 PM

Yes it is and very well. I have now installed 3 hobby king gyros, and it is brilliant. With the gyros active stable and flyable in high winds plus cross wind landings are a no-brainer. Gyros off and it flies normally.


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