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Old Aug 01, 2004, 09:40 PM
Gravity is just a theory.
Capt Crash's Avatar
Nuevo Mexico
Joined Jul 2004
188 Posts
Project Groundstrike journal

I, like so many other poor fools, fell for the lure of the dreaded Megatech Airstrike. Fortunately, I never tried to fly it. I figured (rightly) that I would first get sharp on other, easier to fly airplanes (Firebird Outlaw, Great Planes Yard Stik) before trying to fly the very cool-looking Airstrike. After finding this forum, I realized that I'd been had.

Getting my money back wasn't an option. Fortunately, I bought this husk of waste very cheaply. So, what to do? It was obviously waaaay overweight, and to try it in stock trim was simply asking for a quick trip into the dirt at a high rate of speed. If the lowly bird were ever to fly, it would need mods.

Thus was born Project Groundstrike. I whipped out the tools, and began by dissecting the fuselage. Within were perhaps some of the most fiendish radio control elements ever to see the light of day, or to be destroyed during involuntary contact with the ground during an attempt at "flight".

I kid you not. See the photo for the primary reason why the Airstrike will never fly out of the box. At least not easily. There must be 18 pounds of plastic, about 12 miles of heavy gauge wiring, and all sorts of excess. The motors in the servos look like 180's. Well now.

Stripped of this cancerous system, the airframe and powerplant strike me as relatively light in weight and structurally sound. Next step: surgical implantation of micro servos, micro receiver and speed control, and a different battery. Stay tuned.
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Old Aug 01, 2004, 10:07 PM
Registered User
U.S.A.
Joined Jul 2004
23 Posts
Maaannnnnn,

Thanks for the info. I was looking to get one. Maybe not.
Sorry about your experience Capt Crash, but keep on Flying!!!!!!!!!, just not this one.
----SnapP
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Old Aug 01, 2004, 11:00 PM
PGR
Low AltiDude
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United States, CA, Costa Mesa
Joined Jun 2004
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Looks like the perfect equipment for a powered lawn dart.

Pete
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Old Aug 02, 2004, 12:47 AM
characters welcome!
Mark Wood's Avatar
United States, CA, Bear Valley Springs
Joined Feb 2000
26,446 Posts
The main problem with the GroundStrike is that it was too heavy for the power system and the wings tend to fold because of the weight. Make sure you reinforce them.

mw
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Old Aug 02, 2004, 10:39 AM
Gravity is just a theory.
Capt Crash's Avatar
Nuevo Mexico
Joined Jul 2004
188 Posts
Indeed the power system is heavy. It looks like a 370 motor and a clunky gear drive. Ironically, the system is stamped "enjoy" on the firewall and on the clear plastic that makes up the gear drive. Someone out there has a sick sense of humor...

The real weight is to be found in the massive control system. The plastic used is a cheap, coarse high density stuff. Combine that with a hefty 7 cell NiCD battery, and you've got serious ballast.

Project Groundstrike will keep the existing powerplant, but will be using an FMA direct micro setup, and 7 cell 2/3AAA battery pack. I hope to get some weight comparisons on the stock setup versus the mod setup just for comparisons. And yes, the wing will be reinforced with carbon fiber spars.
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Old Aug 02, 2004, 02:33 PM
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Joined Jan 2003
1,421 Posts
Very interesting contribution that should be helpful to others. An unusual sentence in the Megatech AirStrike description . . "Flies up to 3000 ft above sea level" . . a newcomer to the hobby may not fully realize what this statement implies, and the grief this plane will give them if they reside at a higher elevation.
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Old Aug 02, 2004, 04:09 PM
Gravity is just a theory.
Capt Crash's Avatar
Nuevo Mexico
Joined Jul 2004
188 Posts
The instruction manual for the Groundstrike is good for lots of comic relief. The long warranty statement contains a very nice disclaimer:

"The express warranties contained above are in lieu of all other warranties, expressed or implied, including but not limited to the warranty of merchantability and/or fitness for a particular purpose,..."

So, Megatech basically is saying that claims that the plane is a "trainer" and that it is "easy to fly" are not really valid. Ah, the thrill of corporate chicanery.

The best part is the opening paragraph, second sentence:

"With proper assembly, and by following this instruction manual, your flying success is almost certain!"

I had a good hearty laugh; given the harsh experiences recounted in this forum, that "almost" is doubtless the operative word. "Almost" only counts with nukes and nerve gas; a plane doesn't "almost" fly! Too funny.

Anyhow, I now await the arrival of the desired radio gear. The Groundstrike sits on the shelf, now relatively light, bereft of it's Dr. Frankenstein radio setup. Stay tuned...
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Last edited by Capt Crash; Aug 02, 2004 at 04:22 PM. Reason: Add a photo
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Old Aug 02, 2004, 04:17 PM
Trapped in California
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United States, CA, Arcadia
Joined Nov 2003
1,857 Posts
Wow, look at all that plastic! It looks like an attempt to take an electric plane and beef it up like a glow plane.....
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Old Sep 05, 2004, 08:01 PM
Gravity is just a theory.
Capt Crash's Avatar
Nuevo Mexico
Joined Jul 2004
188 Posts
Project Groundstrike: Radio retrofit

The new radio stuff showed up, and I've made the "conversion" to micro gear. Check out the photos below. The receiver is a Cirrus MRX4 MkII, the ESC is a Wattage IC-15, the servos are two FMA Direct PS20's. Everything was stuck to a convenient surface in the now-cavernous fuselage with double sided tape, and seems to be nice and secure. Cost of all the new toys was about $90.

I kept the battery box, and CA'ed some foam blocks to hold the 7.2 volt 300 mah NiMH battery in place. The ESC got stuck on the topside of the battery box. Everything popped back into place nicely, and from the outside, there's no clue of the nice light gear within.

The wings were definitely in need of some reinforcement. I used some light wood dowels as spars, and glued them in place on the underside with foam friendly CA after pulling up the decals a bit. The tape decals were then put back in place. The wing is now much stiffer, and has no problem supporting the now-lighter airplane.

The stats tell the story. The empty weight of the Groundstrike is now 13.7 oz./388 g. That's a substantial improvement over it's previous porkiness. With the light battery (1.7 oz./46 g.) the ready to fly weight is now 15.4 oz./436 g.
What's most impressive is the change in wing loading. The wing is approximately 213 sq. inches/1.48 sq. feet. The new displacement results in a wing loading of 10.4 oz./sq. ft.- respectable, and within specs of many current trainers, electric sport flyers, and parkflyers. Not bad.

Of course, the real test is flight. I've done my power tests, and the pull seems more than adequate. I await calm weather for that first attempt. Stay tuned...
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Last edited by Capt Crash; Sep 06, 2004 at 01:04 PM.
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Old Sep 06, 2004, 12:46 PM
Gravity is just a theory.
Capt Crash's Avatar
Nuevo Mexico
Joined Jul 2004
188 Posts
Groundstrike maiden flight: feel the fear!

This morning dawned cold and crisp at the old soccer field (6600 feet ASL). I was out with the Groundstrike, ready to put it to the test. I did my range test, and things seemed to work out fine. One glitch that cropped up was the ESC would shut the motor off at full throttle; I'm guessing the voltage drop for the battery pack was too much. Fortunately, it would allow restart. I had to mark the allowed "full throttle" position on my Tx to make sure not to go over it. Still, power seemed plentiful; when wound up, the prop blast would clear the table and blow the curtains around.

Still... lurking in my head were all the horror stories of Groundstrike disappointment and death from this forum. I was scared. I did some running tests with the plane to see if I could feel lift developing; it sure did seem to have more than adequate lift at a moderate jog. So... checking the wind, I cranked it up and launched.

The plane floated away very nicely, climbing out at about 15 degrees, and tracking nice and straight. I tentatively put over the stick for a turn, and the Groundstrike responded gently, easily. As she cruised up the field, I could see that there was plenty of power, and the plane had gained about 70 feet of altitude. I rolled back the power, and the nose dropped slightly. I held about half throttle, and just putzed around the field. The rudder seemed to have plenty of authority, but the dihedral meant that I'd just release the stick, and it would level out quickly.

I did about 6 passes around the field and set up to land. I rolled off the throttle, and the nose dropped, requiring a bit of up elevator to hold it. Still, the Groundstrike settled into a very nice glide, and descended gently. It held onto it's altitude better than I would have suspected, and I almost ran out of field (pucker factor going up here...) but I flared and touched down about 25 feet from the fence. Unfortunately, the little wheels don't seem to care for grass; she flipped upside down immediately. But touchdown was at such a slow speed that it was a nice gentle flip. Nothing damaged, just some dew sprayed on the plane.

No photos of flight (my wife, the in-flight camera operator, is out right now...) but stay tuned, I hope to get some shortly.

The verdict? With the light gear, the plane performs as Megatech says it should. I can't even imagine flying it with the stock gear; it would need tremendous speed just to stay up, and landing would be terrifying. The impact of hitting the ground with all the ballast on board must cause serious damage as well. My Groundstrike is now the docile performer that Megatech promised in its literature. With it's moderate wing loading, it should be able to handle some wind as well. Even though the 6 cell battery is not the most powerful, performance is gained via the lighter weight. I thing Li Po batts would definitely benefit this plane.
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Old Sep 08, 2004, 01:59 AM
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Joined Jan 2003
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The Deception Continues

From their Holiday Preview 2004 catalog:
"This remote-controlled plane takes to flight so smoothly and easily that itís the model favored by international radio control champions for training." . . HAMMACHER SCHLEMMER

They must be referring to Chris Chianelli?
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Old Oct 04, 2004, 05:18 PM
Gravity is just a theory.
Capt Crash's Avatar
Nuevo Mexico
Joined Jul 2004
188 Posts
More Groundstrike fun...

After getting a few Groundstrike flights under my belt, I did some further adjustments. Given the light wing loading, I found it necessary to reduce the control throws a bit. I moved the links in to the hole closest to the servo output shaft, and that seemed to make the plane a bit less sensitive. The surfaces still have plenty of bite without the plane being overly jumpy.

I went out on a fine Sunday morning for some more flights. I was planning to shoot landings and set down on the gravel parking lot next to the field. I launched the plane, circled around, then rolled off the power and set up for approach. Oddly enough, the Groundstrike will float pretty easily, and power needs to be chopped substantially to get it to descend. The plane made a nice approach, and as the wheels drew near the gravel, I closed the throttle, and she settled down on all three. Cool! Nice rollout of about 15 feet. I did one more flight, but as I was getting set up to land, a car pulls into the parking lot, right next to me. A dude hops out and begins quizzing me about the plane. I throttled up, did a go around, and told the guy that I was trying to land. I set up the descent, rounded the final turn, and again the Groundstrike settled easily onto the gravel and rolled out.

I guess that brings up the real lure of the Groundstrike: it looks pretty cool. I had to tell the dude to make sure and NOT buy this particular airplane, since it was a quick ticket to disappointment in stock trim. It seems that the Groundstrike has eye appeal that better flying airplanes lack; every time I fly it, people gather around. I can't remember who said it, but "what a shame it is for humanity that beauty and virtue are not related..."
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Old Dec 21, 2004, 12:01 AM
Gravity is just a theory.
Capt Crash's Avatar
Nuevo Mexico
Joined Jul 2004
188 Posts
A better prop for the Groundstrike

I decided to try a bigger propeller on the Groundstrike; the stock prop was adequate, but didn't seem to be using the available power. I bought a GWS 8x6 and an APC 8x6. Both props work fine, but the APC propeller is the one to beat.

The GWS prop goes right onto the stock shaft with no need for spacers or any modification; I used a Cox 1/2 a flat washer on the front along with the nut. Due to the thickness of the hub, I left the spinner/backplate off. Power and climb were improved, but the GWS props are a bit fragile. That may be an advantage; if you are trying to get the plane dialed in, or practicing landings, it's cheaper to replace a broken prop than to tear down the gearbox and replace a bent shaft.

The APC prop rules; loads of thrust, and it can be used with the stock spinner. Due to the size of the hub, a spacer is needed to center it; I used a bit of 1/2 a fuel tubing. The APC 8x6 really pulls well, and gives the plane quick response to a throttle up.
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Old Dec 21, 2004, 08:11 AM
an earth bound misfit, I
Basketcase's Avatar
St. Pete, Florida
Joined Sep 2001
9,429 Posts
Great job Cap! And very entertaining thread too. I'm glad it back up as I somehow missed it the first time around.

Good to see that the GroundStrike can be modded to be a nice flyer. Even better is that you kept the original appearance and now have a real sleeper.

I definitely agree with you about it's eye appeal. I've seen a number of them show up at the field, even flew one... once. It's a shame that none of the pilots have ever been seen again. I hope they don't get turned away from the hobby for good.

Gotta love that quote posted by Aeropal from Hammacher Schlemmer, too funny!

BC
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Old Jun 11, 2005, 12:34 AM
Gravity is just a theory.
Capt Crash's Avatar
Nuevo Mexico
Joined Jul 2004
188 Posts
The Groundstrike fun continues...

Another summer with the Groundstrike. I'm amazed that this airplane has managed to survive this long. It's back to the old soccer field, shooting landings and just enjoying putzing around with it. I've even managed to have a couple of really neat crashes.

One wipeout came when I was practicing landings. I knew the batt was getting to the end, but it tached up OK when I tested it, so I launched again. I need to pay attention to that "sinking feeling"... As it climbed out, I could hear the motor speed drop. I panicked, and tried to get it back over the parking lot. Bad move. I lost too much altitude in the turn, and caught a wingtip. I cartwheeled the plane, and bent the shaft (had the APC prop on; very strong material...).

I managed to get the shaft straightened out, and decided to switch to the GWS props due to their more "forgiving" nature. I was back at the field a day later cruising around, and experiencing some radio interference. Weird. Finally, on one very nice flight, I got shot down. The motor stuttered, and the plane dived. I gave the stick full up, and managed to level it out just as it hit the ground. It bent the landing gear, and broke the prop, but otherwise no damage. Amazing...
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