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Old Sep 23, 2009, 07:16 AM
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Methuen, MA
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I don't think it was your stupidity that puffed the pack. It was E-Domodel's. The power set up is beyond stupid. You shouldn't have to worry about throttle management to keep everything from melting.

I'm not going to spend much time or money on this either, but I'll fix the wings and struts like you did. Maybe I'll just rip open the supplied 4s pack and take off a cell, or build a parallel harness for smaller 3s packs.

Let us know how the float tests go on Sunday. I'm convinced that with a few tweaks this plane could work well.
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Old Sep 23, 2009, 01:39 PM
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No I did definetly choked that pack. I flew 3 seperate packs that day, one was warm the next puffed and the 3rd hot because of the foam I mentioned and it was placed a little different for each pack so I must have really choked the flow on the puffed one. Tell you what I will run it up on a 3s 2200 today and see the numbers. If I get anything around 350-400w I may go that route as I have 4 of those packs (and 4 of the 4s 2200)

Brent
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Old Sep 23, 2009, 05:28 PM
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Ok only 220w at 22 amps with a 3s and stock prop.
3s with a 2 blade 12/8 numbers were similar to the setup in my DR1 330w 32 amps...but unlike the DR1 for some reasomn the pack started getting really hot quick.
4s with a GWS 10/6 didn't get to full when the prop sounded like it wouldn't take it.
So I'm right back with where I was 4s with managementfor this sunday.

I also blew off the stock prop adapter as even with the nut cranked tight it still was slipping.

BTW the servo tabs on the water rudder did not bottom out to where they should sit as the cavitity for the servo is not deep enough. If you carved out some at the bottom the servo should sit lower and the stock clear cover will probably work. Too latre for mine as it is glued in. I use part of a blister pack to water proof mine.
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Old Sep 24, 2009, 07:25 PM
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Methuen, MA
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I tried testing other props on the 4s pack, but I ran into trouble with the stock prop adapter too. The stock three blader must really flatten out under load, as I found that the skinnny little APC 10 x 5e draws just as much current. The 10 x 5e probably makes less thrust, so the stock prop is really the best hope for 4s flying. I'll probably try to fly it initially on 4s, then change to 3s and a 12 x 6 when I get a chance. I think 300 watts should fly this thing fine in calm weather.

Mine came fully assembled, so the water rudder servo was snugged in under the stock clear cover. I think my example had been a trade show exhibit item.

Let us know how it goes on Sunday.
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Old Sep 27, 2009, 06:44 PM
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Didn't work out for me.
The torque at just above 1/2 throttle is crazy, I noticed it on wheels too.

It wouldn't get off the water, a couple guys (long long time float guys) said it looked like negative incidence, so I drilled to holes a 1/4" higher in the acrylic float tabs to drop the front of the floats down.

But from splashing around trying to get off the water 1st time, I noticed the water rudder wigging out (maybe got wet?).

I removed the water rudder and tried again. It should have lifted of at 1/2 but wouldn't and as soon as power was added it torqued heavy to the left and with full right rudder and tons of up it broke loose and of course rolled hard right and nose high. The extra power and some stick work got me out of trouble and it flew nice, it landed nice. I went again and the batt was low (maybe 6 or 7 min) and I came in a little bit hard. Didn't expect damage but one of the acrylic float tabs broke. Fixed it with ply and epoxy. All takeoffs were the same problem. On the 3rd flight it wasn't getting of the water and the hard right rudder bit me...the prop hit the water, she flipped and I went for a boat ride. The motor mount broke, prop broke, the cowl is damaged near the front and there is a gouge in one float.

Another flyer mentioned that the float step looked like it maybe off in relation to the CG.

I guess I will try to fix it this winter. I doubt I will use the same motor. I will try to drive the water rudder from wire to the tail wheel so I don't have to worry about water in the servo. I will remove all the acrylic and use ply and hard wood.

Too bad. It looked nice in the air and where we fly is stunning scenery, but I was hoping for a ready to go tuned package and not a make work project.

I was disappointed...how disappointed?...One of our club members that was there is a Multiplex dealer, I ordered a mini mag and floats from him .

Brent
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Old Sep 28, 2009, 09:23 AM
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Methuen, MA
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Sorry to hear of the bad day with the Cessna.

I'll check the float incidence and step/CG relationship on mine. I fitted flap servos, so I was hoping the flaps would help it get unstuck from the water, but it sounds like there is another fundamental problem here.

I got mine with a broken acrylic strut mount in one wing, so replaced them with 1/16th ply in both wings. Now it sounds like I should replace all the acrylic. I was hoping this might be a good rig for flying off snow. The acrylic would probably be too brittle for the cold.

The previous owner of mine hadn't successfully flown off water either. His problem was that the floats had started to fill with water in the rear and threw the CG way off. He lost interest after that. I'll have to seal the floats and make sure the water rudder servo is well protected.

I haven't got much into this thing and have no other projects on the bench, so I'll continue to press on. I want to get it sorted out in order to leave it permanently at the in-laws lake home in northern Maine. Looks like I have a lot of work ahead of me, with a good chance of failure.

I checked out all the Multiplex offerings last week at the NEAT fair and they look to be very well sorted out and great flyers. One of the Hitec guys was flying a float equipped Mentor off the pond and doing knife-edge and torque rolls with it. I don't think you can go wrong with Multiplex.
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Old Sep 28, 2009, 11:41 AM
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Hey Mike, Yeah 2 guys were float flying mini mags and 1 the mentor. The mentor got the ESC wet on the 2nd flight but all 3 flew nice.

My only other float experience was with my GWS beaver, it faired far better than the cessna.

Winter flying...exactly what our clud pres. said...the acrylic will become brittle.

I think some of this stuff can be worked out for takeoff and as I said it flew and landed nice.

Our next float fly isn't until spring so I have time to figure it out and get a better suited motor.

Good luck with yours, let us know how your mods work out.

Brent
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Old Sep 30, 2009, 03:21 PM
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Lauderdale
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brent

Sorry to hear about all the problems with this cessna. Seems like to much trouble. Knew it was to good to be true for the price. Btw the mini mag onfloatsnis great and alot of fun. Love mine. Guess I will be getting a mentor after all. Want a 40size. Good luck getting the cessna worked out.
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Old Oct 01, 2009, 12:45 AM
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Yeah I think that other flyer is right about the step. It looks way too far forward as they are usually situated right at the CG.

It might be feasible to push forward on the stick while giving full power in an attempt to get on the step, but it's probably of no use.

Marlin
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Old Oct 08, 2009, 06:50 PM
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Methuen, MA
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Brent,

My Cessna is nearly ready for a test flight this weekend. The weather report for northern Maine looks pretty grim with winds 12-15 mph and temps in the 40s. If I donít get a shot at it this weekend, then it will have to wait for next year.

I replaced the upper wing strut attachment points with 1/16th ply, the lower attachment points with 1/16th + 1 layer of 1/32Ē. I separated the wire struts from the Styrofoam they were incased in and replaced them with rods with 4-40 threads at one end. I screwed nylon clevises on the top end and bent an L shape on the bottom, glued them back into the styrofoam and covered them in Monokote trim sheet. The bottom end is held in place with a wheel collar. This makes for a secure and easily removable strut.

I glued 25Ē long 4mm carbon rods into the wing just as you did. I cut the ailerons free, as well as the flaps and hinged them top and bottom with Monokote trim sheet. This is much easier for the servos to move than the stock set up. I hinged the elevator the same way. I gave the trim material a pressing with a warm trim iron to ensure best adhesion. I noticed the rudder hinges had glue in them and the post that went from the rudder though the fuse to the tail wheel was off-center from the rudder. Both these problems caused the rudder to be awfully stiff, so I ditched the tail wheel post completely and hinged the rudder with Dubro pinned hinges since the bevel wasnít good for Monokote hinges. All the surfaces now move freely and I have them set up for huge travel throws.

I used Monokote trim sheet to surround the water rudder servo cover and the lead going out to the rx. I added a piece of it to the hole in the cover and glued a piece of pushrod guide tube for extra help at keeping water out. I wonít try and fly this thing without a water rudder.

I checked the float/wing incidence and found one float to be about the proper 3 degrees positive, but the other was just 0 degrees. They werenít even parallel with each other. It appears to be inaccuracy in the way the aluminum gear is formed. I made new float attachment points from 3 layers of 1/6th ply and sealed them with thin epoxy. The rear attachment points were drilled just as the originals, but I left the fronts blank. I fastened the rear points, then clamped the front in place after I swung them to the proper 3.5 degrees positive to the wing. Then I marked and drilled them. The original acrylic mounts were 4 times the weight of the ply mounts and a fraction of the strength. The stock relationship of the step-to-CG was fine. With the airfoil level, a line was dropped from the CG (set now at 64mm back from LE) and the step was about 1Ē back, so the new mounts were installed in the same place as the originals.

The floats are hollow and comprised of several pieces glued together. The bottoms were not glued on well and gaps were present that would allow the floats to fill with water. I filled the seams with a mixture of epoxy and microballons.

I fitted up an APC 10 x 5e to benchmark motor performance. The 4s pack spun it at about 10,500 rpm and drew 30 amps, which the battery seems able to supply. Dr Kiwiís thrust calculator shows this to produce about 55 oz of thrust, which is good, but at a pitch speed of 52 mph, which is ridiculous. My gut feeling is that this plane canít possibly go more than 35 mph. This is a pretty high kv motor. It is stupid to use it with 4s in anything but a sleek sport plane. Most of the power of the stock set up is wasted on excessive pitch speed.

On 3s the motor spun the 10 x 5e at 8,800 rpm. That works out to 38 oz thrust (not really enough) at 41 mph (still too fast). Playing with the thrust calculator I found that the ideal combo for 3s would be an APC 11 x 4.75 SF which would make 74 oz thrust (better than 1:1!) at 38 mph. Too bad I wonít have one for this weekend, but maybe I can dig an 11 x 5.5e out of the flightbox.

I would have built a plywood motor mount, but my plane came with the cowl permanently glued on, so Iíll probably only replace the mount if it breaks. Edo-Model saw fit to build the most highly stressed parts of this plane out of heavy and brittle clear plastic. That was stupid. They built a relatively large plane with an un-reinforced Styrofoam wing. That was careless. They also decided that it needed a 4 cell battery pack. That shows that they really donít have a clue about electric power. The rest of the package looks acceptable. Iíll let you know if Iím successful with water operations.
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Old Oct 13, 2009, 03:54 PM
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Methuen, MA
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Finally got it in the water, but no air time for the Cessna. I zoomed it around at seemingly way above stall speed and couldn't yank it off the surface. It was very unstable in yaw, especially when it got light on the floats. I cranked in a lot of rudder expo, which didn't help much. It needs huge amounts of left to get going, then it needs right and when it gets light it takes a hard left turn. It was raining Friday and cold. That was my only chance to be out there before it got windy for the rest of the weekend. Seeing as a rescue mission would involve digging out the kayak from winter storage and risking overturning in the 50 degree water, I decided not to push my luck with aggressive attempts to yank it from the water.

I had my waterplane guru, Palmettoflyer, take a look at the pics and he said the same thing as everyone else, that the step is too far forward. The step on these floats is a highly inclined V shape. The peak of the V is indeed well aft of the CG, but most of it is well forward. You can see that it sits in the water pitched way back. At speed it was dragging the back of the floats instead of balancing up on the step. The entire back of the float must have been submerged as evidenced by the water rudder servo being completely submerged under its filled cover. Fortunately the servo worked fine while under water.

So just as everyone theorized, the floats must be moved back. Perhaps the step should be cut straight across also. At least I have until May to take care of that.
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Old Oct 27, 2009, 07:22 AM
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Methuen, MA
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Brent,

I had a chance to fly mine off of wheels yesterday. I used an APC 11 x 5.5e prop and a three cell pack. Climb was great and it had enough power for enormous loops. Roll rate with the re-hinged ailerons was crisp. It flew great. On four cells it sounds like a glow plane with the prop tips going supersonic and wasting all the power beating the air. On three cells it silently cruises around or goes straight up. No need to replace the motor on this thing. It is a good power system. I'll be cutting 1 cell out of the four cell pack that came with the plane. I got nice long flights out of 2 1200 3s packs running in parallel. This flies like a .40 size sport plane, but floats in for landings like a Slow Stick. I spent lots of time doing low-level flying and touch and goes. Very scale-like flight characteristics. Looks great in the air. I still need to work on mixing for the flaps, as it pitches up a bit on full deflection. You also need to keep the power on when the flaps are deflected. Any stall with this thing ends with a quick 1/4 spin to the right that can catch you off guard. Recovery is pretty much automatic if the controls are neutralized and power applied. The flaps aren't really needed because of the low wing loading, but are fun to play with.

It did need about an ounce and a half of ballast in the nose to balance at 64 mm back from the LE. That is a good place for the CG. I needed three ounces on the tips of the floats to get the CG right with the floats installed. That makes me wonder if the designer moved the floats so far forward in order to try and effect balance without adding a ton of ballast. I was encouraged enough with the excellent flight characteristics of this to go ahead and work out the issues with the floats. My guess is that I'l need to cut the step straight across, mount them about 2" rearward and hide significant lead in the tips. I'll post my results. In the meantime, I'll probably use this thing as a winter beater plane because it flies so nice.
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Old Nov 12, 2009, 05:51 PM
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Looks like you had a similar experience Mike.

Yeah I need to switch out the prop and maybe go 3s too after I rebuild the motor mount.

The stock 3 blade prop is definetly no good. I broke a 10/6 GWS (2 blade) prop on my ultimate and only had one of these 3 blades from the cessna. I put it on and the numbers were similar to the GWS prop. I would do 9 min flights with the GWS prop with no sign of the batt running down but....with this 3 blade the plane performed pretty much the same but the batts ran down at less than 7 min and the batts were hot. Crap prop.

Let me know how you make out with the step on the floats. I too have to rebuild for next year.

Cheers

Brent
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Old Nov 13, 2009, 01:16 PM
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Hi Brent,

I did cut one of the cells out of the supplied 4 cell pack and have been flying it on 3 cells with the 11 x 5.5e, drawing 28-29 amps. It is a really good combo. No problem getting 10-12 minute flights out of it. The aerobatics are surprisingly good including inverted flight. But of course that looks pretty stupid with a Cessna 185. The glow guys get a kick out of seeing the super slow and realistic touch and goes. They can relate to this plane because of the size and the fact it weighs less than 1/2 of what they are used to. I get a kick out of flying this relatively big thing very well on less than 300 watts. It simply doesn't need any more power than that.

I started working on the floats. I mounted one on the plane and made measurements compared to the geometric standards for floatplanes. The nose of the float was approximately 1/3rd of a prop diameter forward of the prop disc, so the float body is in correct relationship to the plane. The standard for step position is 53% back from the front of the float. The stock floats have the step only 40% back from the tip. The critical thing is to get the step behind the CG far enough to account for the "hump angle". To account for this "hump angle" I measured an 8 degree angle aft of the aerodynamic chord from the CG to the float. With the V angle cut off the step (step cut straight across), this point is 4" back. So I'm cutting the steps straight across and will be shaping 4" extensions out of styrofoam block.

I'm pretty sure that this modification will allow this thing to gracefully rotate on water and lift off nicely. I'll also move the water rudder servo up into the fuse and run some spiderwire pull-pull cables through pulleys to the rudder. That might be overkill, but I'm not sure the servo in the float can be kept dry even if the float geometry is corrected. I'll be leaving this plane at the lake, 200 miles from my workshop, and want it to be as trouble-free as possible.

I'm not super motivated right now to get the float modifications completed, as I probably won't get a chance to test it off water until May, but I'll post my progress here.
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Old Dec 15, 2009, 05:16 PM
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San Marcos, CA
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Hello,
I just received my Cessna 185 - ehm - Cessna 182? - Yeah, I got the Cessna as a 182 Skylane in red with a tricycle landing gear.

Looks actually identically except of the landing gear and the color. Has a N-registration, it's big and I am happy with it, but hopefully don't have any bad landings.

All parts were good - I got it as a replacement plane from Bananahobby after 3 months of battling with them.

I already saw a few things which i would like to change:

1) Adding magnets to the cowl (6x) to secure it probably instead of gluing it together. Maybe use Velcro to secure it even more.

2) The cowl needs landing lights :-) and I am going to put the full set on it.

3) Adding Flaps is a must

4) I am planning to use a 4 Cell 3600mAh Battery on it - will that work?

5) Otherwise I will follow the recommendations that I found here.


Thanks,

Andy
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