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Extreme Mini3D with Norvel .15

Steve Herlacher reviews the mini 3d -- a lightweight parkflyer 3d airplane. There aren't many 3d planes in this size, and esp. ARF and this nicely built for only $89!

Splash

Introduction


Wingspan:38.5"
Wing Area:530 square inches
Weight:1.75 to 2.25 lbs.
Length:46"
Wing Loading:7.6 - 9.8 ounces per square foot
Recommended Glow Eng:.15-.25 glow 2-cycle
Engine Tested:Norvel .15
Available From:Extreme Flight R/C

The mini 3d is a lightweight parkflyer size 3d airplane. There aren't many 3d planes in this size, and I can't think of one that is an ARF and this nicely built for only $89! For glow pilots, it is meant for a .15-.25 size 2-stroke engine, although they recommend the .15 as the .25 will make it heavy and you will have to move the receiver battery to the tail. For electric, a brushless motor is recommended, and rumor has it that E Zone will have a detailed review of an electric conversion by David Hogue in the near future!

Kit Contents

Everything came very well-packed and each part was wrapped in thin foam, and then in plastic bags. This packaging is well done and in shipping all the parts remained where they were supposed to be. The kit comes with all the hardware to construct the model. Also included is a vinyl decal for the wing; unfortunately, mine got a little deformed, maybe from the heat, it's still usable though. Everything is covered very well in some type of lightweight covering, its not UltraCote(R) or Solite. I believe it may be Solarfilm which from other models I have had, matches UltraCote extremely well.

Assembly

They don't give you an instruction manual with this model, but don't worry -- they give you a CD instead. On the one hand, I liked the idea that I could see the high quality photos on the computer to help with assembly. On the other hand, that concept doesn't work very well for me, and I suspect for many modelers, because I don't have a computer in my hobby room. I printed the instructions out and it only took 16 pages, so that's not too bad.

Concerns with the Order of Steps

It seems to me that they have you build the model kinda backward, they have you start by installing the CA hinges on the rudder, then gluing the horizontal stab on the fuse, after that they have you mount the control horns on the tail surfaces. I don't like to mount the control horn until I have the servos installed with linkages so I can see exactly where they are supposed to go. I also don't like gluing the horizontal stab on, before the wing is on so I can align the tail with the wing, so I skipped all the steps and went for the main wing first.

Moving on

The first thing you do is cut the covering off the wing opening, then cut out the shipping supports that are within the wing socket (they are notched and come right out). The instructions say that the wing will be a tight fit and may need some sanding, mine was tight but didn't need any sanding. I used a mix of HS-81 and CS-12 servos which are the same servo just sold by different companies.

Filling in the Details on How to Mount the Wing.

The next part was kind of tricky, and the main instructions don't really say how to do it, they just say to glue the wing on the fuse. There was an addendum that helped a little bit though. The problem is, you can't put the wing on with both servos installed as it wont be able to slide thru the fuse. To get around this problem, I followed these steps:

A step-by-step of how to mount the wing and be able to plug in the servo leads easily later.

  1. Mount the wing, measure from the tips to the center of the tail to ensure it is centered, mark where the wing meets the fuse on both sides to allow re-alignment, and remove it.
  2. Trim the covering where the wing must be glued to the fuselage. I used a soldering iron. (If you use a hobby knife, be VERY careful that you don't cut into the wing itself!)
  3. Install the first servo into one wing panel. Allow the extension to extend out the wing center.
  4. Slide the wing through the fuse, and then install the other servo, again allowing the extension to exit the wing center.
  5. Tie the supplied fishing line to both extensions, and push the extension ends back inside the wing.
  6. Thread the fishing line under the wing and behind one former so that later it can be retrieved and pulled to the front of the plane to plug into the receiver. (See photo.)
  7. Slide the wing completely into place, aligning with the marks made previously.

Since it was such a tight fit, I used some thin CA all around the wing joint, then followed it up with a bead of medium all the way around. You can also look in from the front of the plane and drip some glue on the front former.

On to the Tail

If you remember, I didn't like that they wanted me to mount the tail without first mounting the wing. By mounting the horizontal stab now, I was able to align it on both axes. First, I lined it up with the main wing, measuring wing tip to stab tip. Second, I also made sure it was level when compared to the wing also. I used 15 minute epoxy so I would have time to adjust it. The vertical stab was glued on next, it lined up in the pre-cut groove perfectly.

Control Surfaces

Now we have a complete airframe minus surfaces, so lets put them on next.

This is how I do all of my planes with CA hinges. The hinge slots were pre-cut but a few of them were hard to find, so I ran a hobby knife thru them. Put the CA hinge into one surface, then put a pin in the middle of it so when you push the surface into the other side the hinge stays centered.

I repeated this for the ailerons also.

Time for the Rest of the Installation!

I then installed the tail servos. It was a little tricky getting the servo extensions thru the fuse with the wing in place already but it wasn't too bad. Again, a little better planning on the order of steps in the manual would've run the tail extensions BEFORE mounting the wing. I made my own extensions and they were about 30" in length.

Again, because my servos were smaller than standard, I also had to fill in the extra space with a piece of balsa as with the aileron servos. I used some scrap covering to cover it as this area may get fuel on it so it needs to be protected.

All of the linkages were just simple Z bends with the included metric rods and hardware.

Assembly of the fuel tank is the same as any other, the only thing I did was substitute the thicker fuel line they gave for some thinner stuff so it would reach the bottom and top of the tank when flipped around, as this model will be flipped around alot! ;)

A Minor Setback at Engine Mounting

The engine mounting was a problem though. I am using one of the recommended engines, a Norvel .15, but when placed in the mount, the muffler hits the side of the fuse. I either had to cut the fuse out and make it look a mess, find an exhaust port extension for the engine or an aftermarket muffler, or extend the mount a bit. All it took was about 1/2", so I glued a piece of the same thickness spruce on the front of the mount, then I laminated 1/16" ply along the bottom of it to give it some strength.

Important Safety Note for Attaching the Mount to the Firewall:
When you mount the firewall to the engine mount, the instructions don't tell you what to do with the small triangle stock they give you, they go as seen in the picture of the whole mount would just pull out when the engine was running, don't forget them!

The instructions also don't say anything about fuel proofing the mount. I used 30 minute epoxy thinned with 91% rubbing alcohol.

Making Room to Mount Everything

After trying to get everything in the front of the plane I finally gave up. I cut a hole in the pink covering on the bottom of the fuse. I had some pink Econokote that matched it almost perfectly that I used to cover it up after installing the receiver and the receiver battery. I didn't use a switch, as the instructions state, to save weight.

Checking CG and Getting Ready to Go!

We now have a finished airplane. The CG came out to 100mm from the leading edge, which is the rear of the limits in the instructions. I expected to end up moving it back from there, but test flew it as recommended and have found no reason to move it further aft. I used roughly the stock low rates, and high rates of the maximum available throw, with 50% exponential. I used a Hitec electron 6 channel receiver with a 720 nimh 4 cell battery. I will also use elevator-to-flap mixing.

Flying

I took it out, fueled it up and set it on the runway. The Norvell .15 had only been run on the test stand, so I had it set rich for the first flights. The plane took off in a few feet and didn't require much trimming at all, it was pretty windy out but I was anxious to test fly it anyway!

The plane has a very light feel, and seems to do everything in the book. Even though the engine was rich so throttle response wasn't the best, the plane still did everything I asked of it!

Downloads

Thanks, Dave!

Notes From the Video

In case you can't see the video, the model demonstrated very quick roll rates, nice tight loops were accomplished by elevator-to-flap mixing, knife edge pulled to the canopy a tiny (bit but not anything that cant be mixed out for those cheaters. :) ) Flat spins were awesome and I even landed it in a flat spin 4 times. The elevator was so effective that square loops were both impressive and challenging to keep the plane from pulling more than 90 degrees at each corner. There was power to spare, even on a rich-running barely-broken-in Norvel .15. (The manufacturer has video on their site of the plane performing superb 3D on an inexpensive OS .15!) The plane hovers with ease.

After the Video

After my 4th flat spin landing I noticed the elevator was jumping around, I had stripped one of the HS-81 servos and it didn't even land hard. After that, there is no way I would use the HS-55 sub-micros they recommend in this plane, Stick with the HS-81's.

The only thing I couldn't get it to do very well during the video session was a blender and a waterfall but that is only because I had a linkage problem and couldn't get enough down elevator, I have that fixed now and its much better at them than in the video.

Conclusion

The mini 3d is a great 3d plane for the experienced pilot -- including those looking to learn 3D. You can't beat the price and the quality is well above average. The construction isn't hard, but the instructions could use a bit of a rewrite. The experienced builder/pilot will know what to do, like fuel-proofing the engine rails, but a newer modeler, or someone who doesn't usually assemble his own ARFs, might miss something.

If you're looking for the plane that does it all for the right price, you just found it.

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