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Archive for June, 2011
Posted by SkyCadet | Jun 27, 2011 @ 12:32 PM | 3,423 Views
I had a chance last night to try out the Champ's "bush" wheels on a flight last night (Sunday, near 2135 MDT). The plane flew just fine with the new wheels, and they rode the taller, 2" grass much better that the stock wheels.

I only had time for one medium length flight, but the plane seemed to handle the grass a little better with these larger wheels.

SkyCadet
Posted by SkyCadet | Jun 25, 2011 @ 07:45 PM | 3,158 Views
Well, I decided to add some slightly larger wheels on my Pilot 1 Champ to allow it to handle longer/taller grass better, but I wanted to avoid overdoing it in case the CG gets out of whack with larger tundra type tires. I decided on a compromise, and used 9/32" carbon fiber rod as shims inside Dubro 2.75" foam microlite wheels. See picture below.

Too windy today to fly, maybe tonight if wind dies off.

SkyCadet
Posted by SkyCadet | Jun 25, 2011 @ 12:36 AM | 3,191 Views
After a superb 14-minute flight with the new upgraded Champ, I only used 1060mAh - 50% battery! Mostly cruise at 42% throttle, but I did a few 55% climbouts here and there. That's about 21 minutes to 75% battery consumption, so this is pretty close to my older 450 motor's current draw, but WAY more pep, as mentioned before...

TO was about 10-12 feet max with a nice 45 degree angle up - just BANG! - and up she went, level as a feather and straight like a rocket...

I did a great "crop duster" landing by zipping about 5-8 feet over the tree line and glided to a nice 10 foot rollout on TD. One of my neighbours sons saw my plane land and was curious - at first he thought it was a stock plane flying low, until he realized by the motor noise that this was NOT a big plane...

I am really enjoying flying this plane in our local school field - both TO and landings are awesome even in nearly 3" grass. I try to stay in as short a grass as I can get for TO, but TD seems fine so long as the elevator stays up after TD...

SkyCadet
Posted by SkyCadet | Jun 15, 2011 @ 05:27 PM | 3,424 Views
This past Sunday, I was able to maiden the Pilot-1 champ with the newly installed RC Timer 2836/7, 1120Kv motor!

The motor did a fantastic job getting the plane up fast! 10-12 feet and it was flying. At least 1/3-1/2 what the previous [EF 450] motor gave.

After flying 10 minutes, cut short due to some light rain sprinkles, the plane consumed 720mAh, including a 10s at WOT [25A+], 8 minutes of general cruise around 40% throttle, 1.5 minutes of 55-60% throttle for climbing turns and climbouts, and landing. That's about 35% of the battery after 10 minutes, and is nominal to what I would see with the previous power system.

The plane apparently flew a bit peppier, and was less affected by light headwinds and climbing turns with this new power system.

A successful test. I was happy to see theory and reality overlap with this system! I may do the same retrofit to my Lancair ES as it has the same 450BL/20A ESC power system, except the Champ has a 30A model. I would most likely change out motor and ESC to run the 1120Kv in that plane. We'll see. Retesting static 100% throttle rotations, the 9x7x3 tops out at just over 9000 RPM.

SkyCadet
Posted by SkyCadet | Jun 07, 2011 @ 11:40 PM | 3,537 Views
Given the great performance I saw with the RC Timer 1400Kv motor on the Super Decathlon, I thought that I might try out a higher rating one in the Pilot-1 Champ in lieu of the 450 EFlite BL I was using.

They came in the other day, and fit with the same hardware that the 450 does.

Using my 9x7x3-blade MAS, my WOT static testing showed a total wattage of 290Wp on my meter, 25.8Ap. At 50%, the plane's 1120Kv motor ran around 6200RPM, and ~110W/7.8A. THis is close to the 75% number I saw in my Lancair with the 450 BL tests I did. (see earlier blog entry on the 450 motor tests) WOT on the 450 was around 195Wp/16A, so this is a significant increase in shaft power too. The Eflite 30A Esc handles this just fine.

I had a LOT of trouble holding the plane myself during the testing, so WOT top end RPM was not measured precisely using my Hangar 9 photoelectric tachometer, but it was reading over 8200 in the 8200-8900 range (by then, it was getting a bit dark during the static outdoor tests). I'll recheck this next time out.

For a $15 motor on eBay, I was impressed, and can't wait to fly her with the new motor. I will most likely be cruising now around 40% throttle for level flight, where I'd fly 55% before. I should see close to nominal flight times, but we'll see. the RC Timer 1120 Kv motor is rated to 336W max, so we are fine for the motor usage in this plane as per what WOT gives.

One interesting thing here is this is backwards from what I did with the Decathlon: I went down in Kv a tad, versus up in the P-1 Champ. Usually, a higher torue, lower Kv motor should run higher RPM, but then one also has to look at overall wattage ratings too, as more power into the motor, even if not running top efficiency at WOT, should still produce more shaft power and thrust in general when flying. I suspect that this new motor will have the Champ flying more in a sport category vs a stock trainer category now.

SkyCadet
Posted by SkyCadet | Jun 04, 2011 @ 09:37 PM | 3,132 Views
Now we're ready to finish the model!

First up - coating the tail and wing with white glue.

Part 12: coating lifting and control surfaces - 1h

Use 30-40% diluted weldbond (or other white glue), and apply to ALL lifting surfaces, flowing out to even the coating. On the tail, be mindful not to get glue in the hinges of the control surfaces.

I usually apply two coats to the wing, esp. on the outside edges where the wing may be subjected to touching the ground on a bad landing, or during a tight turn to avoid an obstacle. Before application to the wing, attach the strut clevices with some CA, and then flow white glue out over the upper and lower wing body - INCLUDING the centre sections. I use a Qtip to dab additional glue around the clevice mounts to strengthen them.

Let dry overnight or at least 8-10h to ensure a good cure before applying any decals. Add additional glue coating after 2h to elevator leading/trailing edges and top of rudder.

Part 13: Decals, gear install and CG test - 30-60 minutes.

Start with applying decals to taste, rubbing out any bubbles. Once applied, then attach the gear. I prefer the Dubro 1.75" foam lightweight wheels over the stock landing gear and pants, because the wheels roll better on both asphalt and grass, and give a bit of extra nose clearance as well. If you opt for this, the stock gear hardware may be used, with some small washers on either side of the wheel to ensure smooth rolling, and some lock nuts on the inside...Continue Reading
Posted by SkyCadet | Jun 04, 2011 @ 08:08 PM | 3,097 Views
Now that the tail assembly is finished, we can now reinforce the body with GE.

Part 9: Undercarriage and gear strut reinforcement with GE - 1 hour.

Before doing the first jobs on the plane, I color matched my struts with lemon yellow acrylic enamel. Two coats, left for about 24-36h for curing. Taking the struts, These are inserted in the slots on the underside of the fuselage. I initially poke them partially through, then pull almost out, leaving ~1/4 inch inside the fuse.

mix GE and apply with a brush onto the upper and lower exposed strut sections, before insertion. Do not overdo the application here too much, or the material oozes out of the slots, and runs over the fuselage and newly-painted struts. Wipe excess cleanly, leaving a little GE to flow out where the slots are. This adds some rigidity to the gear. You want enough GE to flow inside the strut housing, to hold it well in place. cure time 30 minutes. Leave the wheels off the gear strut during this procedure.

While the gear is curing, mix a LOT of GE, and apply with a brush inside the body of the plane half way up the fuselage sides, and over the plastic strut housing. This will assist in adding a LOT of strength and support to the gear assembly during rough landings. My plane before handled 0 F temps on hop landings on skis and this led to the failure after >200+ flights and landings. Had this been flown in spring, I'd not have had these issues. Uncoated, the body would have failed long before.

...Continue Reading
Posted by SkyCadet | Jun 04, 2011 @ 01:46 PM | 3,007 Views
Once the part one steps are done, I then go to the tail, graphite epoxy the wheel mount, and the interior of the plane...

Step 5: Tail Assembly, time - 30-60 minutes

The PZ Decathlon tail comes with control horns, rudder, elevator, and a mounting block. I use CA on the block to affix to the horizotal stabilizer - the block has 2 slots and 4 pegs/posts which puncture the elevator section to eventually mount the rudder. Once attached, use CA on the rudder where it mates to the slot on top. Ensure that the empennage is SQUARE at this time. It is important to get the tail properly aligned to the fuselage so that the plane not only looks good, but flies true. Much less trim req'd if done right.

Step 6: Tail installation time - 30 minutes

Once the CA is dry, Check the slots where the tail fits into the fuse, and test fit it to make sure that it will mate well. I often have to cut a small slot on top of the fuse where the rudder tab mates into the unit or else it won't go on right. I use a hobby knife to check that the tail can split at the rear a touch to fit the tabs properly, just tane care not to rip the tapes on both the upper and lower sections (other than the cut if needed to mate the vertical stabilizer front to the fuselage).

Use 1:1:1 [hardener:resin:graphite] 6-minute graphite epoxy (GE) to mate the tail to the rear of the fuselage. I use powdered lock graphite - available at many hardware outlets. It goes a LONG way, and it changes the rheology (flow and...Continue Reading
Posted by SkyCadet | Jun 04, 2011 @ 12:58 PM | 3,098 Views
Well, my plane had a gear [undercarriage] failure last weekend, and while it may be repairable, after 300+ flights, I thought it easier to semi-retire it for now, and build a new one - same effort to do. The wing is still fine, so it was used for this plane as well...

I will go over the sequences I use to build one of these planes from parts and how it is done, for those interested in doing the types of mods I use:

Step 1: time - 5 to 10 minutes

Dremel cut or remove the tail skid. I used a dremmel, and then smooth off the remaining sections (see attached pix) to permit Dubro micro tail wheel to be used as a steerable tail wheel. I also drill holes to match the "ring" to the rudder's hinge position.

Step 2: time - 10 to 20 minutes

Use CA to mold the wing mount on the fuselage (if needed) to maintain a proper surface to make wing mount square. Many of these fuselages have small variances and defects during manufacture, storage, and shipping. I like to make sure that the wing will mount square to the fuse when assembly is complete. Allow CA to cure well before moving on.

Step 3: time - 10 to 15 minutes, drying time 1-2h

I use weldbond white glue on the inside of the fuse under the wing, about 1/2 way down the fuselage sides (where the window decals would go, but inside the fuse). This stiffens the fuse, and minimizes flex. I also apply at this time with a Q-tip shaft glue to the wing rods on the outside where they meet the fuselage, and aply...Continue Reading