Aerospacer's blog View Details
Posted by Aerospacer | Sep 21, 2017 @ 02:40 PM | 3,991 Views
This is a followup to my build post of the Eachine Micro SkyHunter FPV.

To date, I have about 15 flights (all LOS) on the SkyHunter. I started with the stock 6x3 prop and 3S-1000mAH battery. Flight times are 8-10 minutes which consumes about 55-65% of the battery capacity. Cruising is done at 50-75% throttle with full throttle reserved for up-line portion of aerobatic maneuvers. The CG is at the recommended marks on the wing. It seems to fly neutral with respect to nose or tail heaviness.

Initially, I had too much gain for roll stabilizing by the Lemon Rx receiver so it would oscillate the wings at high speed. After some adjusting, the SkyHunter is now very solid in roll and pitch for 10-15 mph winds. The wind does still induce some tail wag (yawing) even with the extra sub fin surface I built into the tail booms.

For my flaperon setup, I have two notches of flaps, 10 degrees and 20 degrees down. Flap deployment caused a slight down pitch which I offset with some up elevator mixing. There seems to be no appreciable drag added at 10 degrees and only a minor amount at 20 degrees. But additional lift at lower flight speed isn't as plentiful as I'd hoped it might be. Even though the flaperons are positioned on the outside half of the wing, the stalls don't produce any snap roll tendency, only an occasional mild wing drop. Using the 10 degree flaperon setting at 3/4 throttle for hand launch does seem to afford a steady climb out without requiring constant control...Continue Reading
Posted by Aerospacer | Sep 18, 2017 @ 05:40 PM | 5,181 Views
Bolstered by my fixed wing FPV success with the Multiplex Shark, I began to consider something else to try in the fixed wing category. One plane that I had considered before was a Mini SkyHunter. From forum threads and reviews, I couldn't tell if this was a good choice or not. Then along came a micro/nano (depending on who was selling it) SkyHunter 780mm wingspan version both virtually the same and design, just different foam material and color.

I selected the white Micro SkyHunter from Eachine that included all the servos, motor and ESC, adding the Eachine TX-03 AIO FPV cam like I am using on my Multiplex Shark to round out the package. I then read through the threads here on RCG for both the RMRC Nano SkyHunter and the Eachine Micro SkyHunter seeking ideas that might optimize the build.

When the kit arrived, I casually inspected it to see what additional detailing seemed appropriate as I put it together. First I wasn't too impressed with the elevator servo cover. It was a very bulbous vacuum formed plastic piece that gave the impression that it could blank a fair part of the elevator surface behind it. So I peeled the cover off and also made some room along a side of the servo pocket to store some of the excess lead wire leaving only enough length to reach the left tail boom. The short little pushrod wasn't running squarely between the servo arm and elevator control horn, so I flipped the Z-bend to the inside of the arm. This flipping of the rod Z-bend was used to...Continue Reading
Posted by Aerospacer | Sep 18, 2017 @ 01:54 PM | 4,896 Views
Soon after my blog entry last year, Multiplex apparently discontinued the Shark. However, I continued to expand the use of the one I had but didn't post anything because I didn't think it was noteworthy as Sharks weren't to be had any more. I first mounted a 808 #16 key chain video cam on my Shark and had a good time shooting video especially off the water. Then I mounted a all-in-one FPV cam on it so I could transition from my FPV quadcopter flying to fixed winged.

My first attempt was a Eachine EF-01 FPV AIO Cam fitted on top of the wing just behind the canopy. I was doing a ride-along flight with it to get the feel for the view and range when the plane crashed due to what I eventually deduced was a failure of the OrangeRx receiver. Though substantially damaged (mainly the wing), I rebuilt it and upgraded to a Eachine TX-03 AIO Cam that provided 50mw and 200mw output strength to take advantage of the Shark's flying range. I also replaced the OrangeRx Spektrum compatible receiver with a Lemon RX gyro rate stabilized receiver.

I have been flying the Shark FPV all this summer with at least 30 flights logged, typically 7-8 minutes per flight. I have flown exclusively with the Shark on its the landing gear with my stearible tail wheel mod. All takeoffs and landings have been done under the FPV headset without a single incident. The Shark will do numerous aerobatic maneuvers with the added performance I got with the prop and ESC upgrades I had previously done for LOS...Continue Reading
Posted by Aerospacer | May 19, 2016 @ 12:38 AM | 6,928 Views
After a number of successful flights off the ground with its landing gear along with my steerable tail wheel modification, I moved on to try the Multiplex Shark off the water with its hull/float set.

First I did a static floating test to see what I might do for a tail rudder to provide the same degree of positive steering as taxiing on the ground. However, I was dismayed to see how much the tail of the fuselage sunk into the water. This motivated me to try something to help raise the tail out of the water as well as steer it. I came up with the idea of a kind of hydrofoil rudder, reasoning that a small ski-like device would lift the tail out of the water once the plane was under motion similar to how the step in the hull does.

I fabricated a hydrofoil style rudder out of some Lexan poly-carbonate plastic sheet I had left from a desk top protector. I fitted this assembly to the tail wheel strut such that only a single screw secures it and is swapable for the tail wheel as easily as the float/hull unit.

With my water steering device in place, I went to the next phase of testing, low speed taxiing, followed by high speed runs getting the hull up on the step. The tail rudder seemed to come up on step right along with the float/hull and skimmed along on the water perfectly.

Next test phase was to lift off the water and get some air time with the float/hull set on it. That's when "bad Shark" appeared and things went south in a hurry. Once in the air, it was very...Continue Reading
Posted by Aerospacer | May 10, 2016 @ 12:59 PM | 7,393 Views
Did not buy the Multiplex Shark but received one new in box. Was barely aware they even existed. Before I undertook assembly and flying, I looked around at reviews and forum threads to see what others had to say. Quite a mixed bag. Generally, there were lots of positives when it came to the details of workmanship and design. But when it came to flying, the Shark was not nearly so universally acclaimed as most of the line of Multiplex models are. I have owned or flown 6 different models from the Multiplex lineup and found them all respectable, albeit benefiting from various modifications to perform to their utmost.

As many have commented, the stock prop is an enigma. As it comes mounted, with the tips curled forward, static power was around 90 watts (7.9 amps) on a 3s-1000 battery @WOT. When I flipped it so the tips curled back, I got about 100 watts (8.6 Amps). Normally, props draws less amps when they run “backwards”. Yet based on the airfoil shape of the blade cord, you’d think the prop was meant to run as it came mounted. So far, I’ve not tried to fly my Shark with the Multiplex stock prop.

I’ve noticed couple of things in regard to the motor mounting that could cause motor drag. The motor wires wrap very closely around the outrunner can. There is some relief cut in the ID of the foam cowl to help the wires clear but a little more seemed warranted to ensure there always is clearance. And the prop adapter could also rub on the motor...Continue Reading
Posted by Aerospacer | Jun 26, 2014 @ 10:43 PM | 9,059 Views
I started this project last fall but winter closed in with a vengeance, so I left it to finish this spring. But then my club decided to put in a hard surface runway on our field, so much of the spring was devoted to that.

When I'd left off last fall, I was just about to detail Park Flyer Plastics canopy kit I got for it along with the belly pan. I also took the suggestion that Keith Sparks of Park Flyer Plastics when he modified his Stinger. I cut a hatch in the turtle deck to allow the receiver to be mounted up there and clean up the wiring.

The stock ESC for the Stinger 64 HP is physically very large and tough to place in the fuselage behind the battery. So I used an old Castle Creations Phoenix 45 and added a UBEC to handle the servos/Rx off the 4s battery voltage that the Phoenix 45's on-board BEC isn't rated for.

Today, I made the first flights with my Stinger 64HP. I used a 4s-2200 mah battery. The all up weight was 29 ounces (820 grams) surprisingly quite a ways north of the 600 grams listed as the max for the Stinger on Hobby King.

I had the CG set between 60- 70 mm back from the leading edge reference shown in the manual. On the first flight it exhibited many traits of being quite nose heavy. Needed up elevator trim, almost full down elevator to fly inverted and almost full up to pull through the corners or the down side of a loop.

So for the second flight, I moved the battery back about 1/2" back from the front of the compartment but it didn't help...Continue Reading
Posted by Aerospacer | Feb 19, 2014 @ 09:42 PM | 7,630 Views
Living in Minnesota on a lake no less, I've spend a good portion of my 30+ year RC flying with float equipped planes. Once I made the full transition from glow to electric powered, I went from just a couple ROW aircraft setups to about a half dozen. Last summer was the second season with a particular favorite of mine on floats, the Parkzone Wildcat. After I got a hold of the TH Hellcat, it just had to go onto floats.

When I was zeroing in on floats for the PZ Wildcat, I was quite familiar with the ones that Multiplex provides for their Mini Mag. These floats are one of the more nicely engineered that I'd come across for light electric aircraft. The Elapor foam that Multiplex uses is very strong, light and smooth surfaced. These floats are close to what I thought would be an appropriate size for either the Wildcat or the TH Hellcat. Technically, they are a little shy in length but I found their water handling under the Wildcat was still excellent. The TH Hellcat's metrics are very similar to the PZ Wildcat so why not go with a proven setup for the Hellcat.

To start off with, I have always added a little more durability to the Multiplex MM floats by covering the bottoms with packaging tape. To prep them, I lightly sand off the mold nibs and fill the hole behind the step where the mold fill plug depression is. Then wipe them down with some lacquer thinner. My supply of packaging tape is all in 2" width rolls, so I cover with multi-strips across the bottoms. I...Continue Reading
Posted by Aerospacer | Nov 28, 2013 @ 10:12 PM | 7,647 Views
After seeing a couple of these flying back in October at our indoor venue in the Minneapolis HHH Metrodome, I did some more research to find out if they were possibly a hidden gem of park flyers. Of course I found an extensive review thread in RCG's eZone started by Jon Barnes back in March of 2010. I was almost dissuaded from getting one by all the negative posts on the durability of GP's version even before you could take it out the the box.

Then one of my fellow Metrodome fliers let me take his up for a few circuits around the Mall of America Field and told me that they aren't all that fragile. Always wanting a Tiger Moth since seeing the GWS version fly in the Metrodome many years back, I pulled the trigger on an order from Tower Hobbies.

Since this was primarily going to be an indoor and calm weather park flyer, I didn't want to more than double the investment by following the GP recommendations for electrical bits to complete it. First off, I already had a Castle Creations Phoenix 10 ESC and a couple of small 2S lipo battery packs. So I needed only servos and a motor. I decided to shop for them at Value Hobby because they had a close match to the Rimfire 250 outrunner motor in their G-Force 2204-1800 KV and so I added to that 3 of their digital 6 gram Power HD servos and a 8x4.5 SF prop. Those together were less than a Rimfire 250 motor from Tower Hobby.

When the Tiger Moth parcel arrived from Tower and I opened the box it was amusing to see the caution card...Continue Reading
Posted by Aerospacer | Nov 08, 2013 @ 10:12 PM | 9,682 Views
For the indoor flying season here up north, we break out the micro aircraft in our fleets. After flying mostly larger aircraft all summer with multi-cell LiPo's, it can seem that by comparison, we are running blind when it comes to the battery condition you can discern on the typical equipment available to maintain the small single cell LiPo's.

One of our electric flying association members came across a neat component to help out with that problem. It is a small 3-digit self-contained digital voltmeter module that can be obtained for less than $3 each. He obtained 100 of the digital display volt meters for our members to build a tester that he designed. These are available on eBay from a multitude of sellers such as item # 360713999468 from axeprice which is identical to the ones we are using.

The voltmeter is 3-digit display auto range that measures up to 30 volts and requires from 3 to 12 volts to power it. So it is well suited to either the 1S/3.7 volt or 2S/ 7.4 volt LiPo's we use in the typical micro aircraft. With the addition of some suitable load resistors and switches, you can have a tester to measure battery voltage under load to determine if your batteries are capable of delivering the capacity required.

To increase the versatility of this tester, I added some features to the basic design. A second connector that allows me to tie in one of the basic 1S chargers for monitoring voltage during the charge and an isolated input to measure batteries up to the...Continue Reading
Posted by Aerospacer | Oct 06, 2013 @ 01:51 PM | 8,435 Views
This aircraft will be my 5th EDF aircraft. Got it because I saw a local pilot who is a skilled aerobatic flyer doing very smooth maneuvers with it. Mine is purchased from Motion RC.

Initially, I planned to throw it together quickly and get some flying in before the fall weather here in Minnesota got too nasty. But as I am want to do with all my aircraft, I began to get picky after I encountered a problem with the horizontal stabilizer. The elevators were severely hinge-bound. I found that the plastic pivot hinges that supplement the live foam membrane hinge were over glued to the extent that glue flowed into the pivots and locked them up tight.

I contacted Motion RC and they quickly sent me a whole replacement tail package (both horizontal and vertical tail). The replacement horizontal stab had the proper amount of glue for the plastic hinges but was still somewhat hinge-bound. Turns out that both examples I had (and I'm presuming all of the horizontal stabs) are built with the outboard plastic hinges set too deeply into the surface so that they are off line from the flex line of the foam membrane. Whereas, every other plastic hinge on the rudder and ailerons are properly located.

Meanwhile, I'd have to extract the elevator servos from the over-glued stabilizer and transplant them to the replacement stab. The servos themselves also had so much glue in their pockets and didn't lay down fully which in turn kept the stab from seating properly on the fuselage.

At...Continue Reading