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Z-8's blog
Posted by Z-8 | Aug 08, 2010 @ 07:31 AM | 2,628 Views
Genius, or insanity?
Posted by Z-8 | Jul 31, 2010 @ 03:54 PM | 2,760 Views
This question seems to come up a lot. Here is the theoretical, full throttle flying time with a given battery.

(Battery mAh in Amps/ Power draw in Amps) * 60 = minutes of flying time

For example, using a 2250 mAh battery:
(2.250/ 34.6) * 60 = 4 minutes of flying time

If you are going to fly less than full throttle, use your anticipated average power draw in Amps. Or, simply multiply the result by a similar factor.
Posted by Z-8 | Apr 02, 2010 @ 07:10 PM | 3,323 Views
Moved to Parkflyers thread.
Posted by Z-8 | Apr 01, 2010 @ 11:20 PM | 2,976 Views
Moved to thread linked above.
Posted by Z-8 | Apr 01, 2010 @ 07:46 PM | 3,042 Views
Disregard the following findings, the only significant finding is the Power 10 may have fried my 40A ESC. After a quick run on a 60A, I think everything is going to be higher.

===========

After the visual inspection was so interesting, I decided to do a quick test between the P10 and ST10 to see if this was going to be a TKO. I've read that the Power 10 is substantially more powerful than the Turnigy motor--and given the Super Tigre is half the weight and 1/3rd the price of the Power 10--I thought if thrust was even close then I would stop here and not even bother with the comparo.

That was not the case (darn it, more work for me).

I went with the NRG 35C battery and APC 10x7 for a quickie, since it was the only prop that I had two brand new copies still in bags. Prop shaft adapters turned out to be more of a PITA than I anticipated, I'll probably limit the number of props I test from the original plan. Anyway, right off the bat, the Power 10 generated substantially more installed thrust than the others:

Power 10 - 42.5 oz (1.25 Thrust:Weight)
ST.10 - 33.8 oz (1.06 Thrust:Weight)
Stock 480 - 25.9 oz (.80 Thrust:Weight)

Weight includes plane, engine, prop and battery.
Posted by Z-8 | Apr 01, 2010 @ 03:00 PM | 3,184 Views
I haven't even taken everything of boxes yet, and it's already interesting. First thing I noticed is that, in the Monster vs Mouse category--the Power 10 and the ST .10--the guts are visually, nearly identical. Each one has about about 0.5 inch (front to back) and 1.1" (diameter) copper coils.

The primary visual difference is empty space and thickness of the casing. The silver portions of the Power 10 case are entirely empty, as is a small portion of it's black central casing. The ST .10 casing is full. Another obvious difference is the ST .10 has thicker, stiffer, lower gauge wiring.
Posted by Z-8 | Apr 01, 2010 @ 08:19 AM | 3,326 Views
I'll be posting a T-28 head-to-head (flying + installed static thrust tests) using:

Stock motor
E-Flight Power 10
Turnigy 35-36C
Super Tigre ST .10

...as soon as $69 shipping gets the Turnigy motor here. It changed from Processing to Shipped yesterday, 6 days after I placed the order (everything was in stock). The international shipping company's tracking system doesn't seem to work.

All of the engine samples will be brand new/never flown. Draft spreadsheets attached. The formulas for Installed Static Thrust incorporate the weight of the plane, motor and prop in each calculation. I would like some input on the Overall Rankings, particularly on the weightings and how to figure the upgrade price.
Posted by Z-8 | Mar 30, 2010 @ 01:46 PM | 3,441 Views
Available by PM.
---------------
Looks like my gear mod for the T-28 is going to work out, I just need a servo from the hobby store to finish it up. This makes the main gear retractable, with an up and down lock, using nothing more than two additional servos. Easy mod. Total installation time is an hour. I will try post pics to the blog in a day or so.

There might be a way to do a nose retract, but it would not be this easy. Time to make your 28 into an F8-F tail-dragger, or settle for two.

Two Out of Three Ain't Bad (5 min 30 sec)



Posted by Z-8 | Mar 30, 2010 @ 04:48 AM | 3,491 Views
This might be the most boring set of videos ever posted on the internet.

49 patterns on this flight and I think they got worse the whole time (the camera batt dies on #46). Part of the reason is an ever increasing headwind and only compensating for the previous amount of wind each time around. Another problem is a lack of skill. Plus I think I need to turn the expo off for landing from now on--too touchy after half stick.

It's easier to see the plane by double-clicking on the video to view full size on youtube, rather than watching inline with this message....

Parkzone T-28 Touch and Goes Part 1.avi (9 min 50 sec)

...Continue Reading
Posted by Z-8 | Mar 28, 2010 @ 03:42 PM | 3,499 Views
This morning I did quite a few speed runs and was happy to see very consistent results. To calculate the exact length of the test run, I used Google Earth Professional to locate my starting line (cul-de-sac west curb) then measuring using the cross-hairs tool to the exact Finish Line (a manhole cover). Track length: 646.2 feet. I think the overall speed calculations will fall within a margin of error of 1-2 mph, as explained below.

To record and ultimately time the trials, I wedged my keychain cam into the T-28's largest bottom fuselage circular hole, behind the rear wing attach point, looking straight down. Then I used the Windows Movie maker's time-readout to clock the time, frame by frame. It was easy to derive the exact speed of the airplane.

Surface winds were north to south, almost a pure perpendicular cross wind (right to left in the ground video orientation) at ~ 8 mph. I did two opposite direction runs to cancel the wind--one was unmeasurable due to being off target, and the other was the last trial shown below with a decrease of only 2 mph.

The effect of the 8 mph cross wind was to blow the plane 70 feet to the right of course each 6.0 seconds, making the run 650 air-feet long (the hypotenuse of a 646/70/650 right triangle). That only adds 0.42 mph to the measured speed. Net subtraction is 0.57 MPH for a 1 MPH tailwind to arrive at a wind corrected GS of just 0.42 MPH slower than calculated. Since the my flight path control was less than a perfectly...Continue Reading
Posted by Z-8 | Mar 27, 2010 @ 07:49 PM | 3,315 Views
A few have asked me to post my background. So, ok...

I am a still-flying "retired" pilot re-discovering my RC youth. My new plan is to throw money at the hobby, eliminating most of the build time and spending more time enjoying flying, but I've discovered that you can quickly accumulate a lot of very large things this way.

What fun. RC has come a long way from the OS .40 Sig Kadet and Kougar I flew as a teenager, with nicked-up finger starter and square metal block Kraft 4 channel radio. I remember mod’ing it with an LED power light. Or maybe, things haven't come a long way, I just found both models on Sig's website, still for sale. But I'm pretty sure I paid half that.

I started my love affair with 1:1-scale flying by soloing a semi-dangerous, underpowered T-tail Piper Tomahawk at age 14. Fortunately, it was up-hill from there. Technically, I am an Aeronautical Engineer, but luckily I never had to use what little I learned in school. I spent my career flying the F-16CG Blk 40, racking up about 4,000 hours of which 300 is combat time with just under 100 missions. It’s finally time to relax.
Posted by Z-8 | Mar 27, 2010 @ 06:15 PM | 3,561 Views
Today, the world stopped for a moment as I unveiled the MkII version of my internationally famous, T-28F Meteor. A little history:

T-28 Park Zone's original trainer in Navy colors
T-28D Park Zone's USAF trainer version
T-28E Meteor - Single seat speedster with giant PZ pilot
T-28F Meteor - 0 seat version
T-28F Meteor MkII - Engine mount extension, twin battery monstrousity

Here is the T-28F making four high speed passes @:
0:08
0:49
1:29 (fastest pass @ 76mph - measured frame-by-frame between landmarks using on-board video)
2:13

T-28 w/ST .10 Motor, NRG 35C Battery and APC 10 x10 Prop - 4 High Speed Passes (2 min 52 sec)

...Continue Reading
Posted by Z-8 | Mar 27, 2010 @ 05:44 PM | 3,274 Views
There are probably hundreds of motor options for those want to give their T-28 more punch. But at what dollar and time investment? Super Tigre's new ST .10 is a great lightweight motor that gives the T-28 a huge performance boost for a $25 total outlay. If you are conservative with your propeller selection (stock prop or around 10 x 6) you can still use the stock 30A ESC.

If you want more performance later, add a 40A ESC, a fast battery, and a Master Airscrew 10 x 7 x 3 for all out performance, great looks and a meaner engine growl. I've measured this combination and it increases the T-28's thrust-to-weight ratio by about 75% to 1.3 to 1. A 25C battery or slower will keep you in the ST .10's maximum burst Amp and Watt range of 370W and 31A. I've used a 35C battery for a long time with no damage (measured pull: 35A and 405W), but do that at your own $25 risk.

As an added bonus, the motor only weighs 2.4 oz (the Park Zone 480 weighs nearly 60% more), so even after parts for installation you can save an oz to an ounce and a half in the nose, on a 30 oz plane. Losing the weight at the very tip of the CG seesaw carries the added bonus of losing the same weight on the elevator side in required down force to hold up the nose, making the T-28 noticeably more docile in pattern turns and on final, with slower landing speeds. You'll also enjoy better overall handling, a tighter radius and loops.

The attached "how to" shows the my installation method with 3/4"...Continue Reading
Posted by Z-8 | Mar 27, 2010 @ 05:24 PM | 3,571 Views
This mod adds 1 to 1.5 oz more installed thrust to a stock Park Zone T-28 Trojan. That might not sound like a lot, because it isn't. The stock Trojan generates about 23 oz of thrust, so this freebie buys you around a 5% boost. The more you hop up a Trojan, the more it helps. The highest boost I've measured is about 3 oz using a stronger prop, battery and motor.

In general, the more a prop is steeply pitched, with a wide chord toward the hub (in front of the T-28's cowling), the higher percentage of total thrust this mod will salvage.