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Old Apr 09, 2003, 10:39 AM
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mars's Avatar
San Francisco, CA
Joined Jan 2002
577 Posts
Hellcat, Take 3

Specs:
25"w.s.
100sq.in. area

The first one exploded on "landing" due to pilot error

The second one flew great (non-aerobatic) on an M-100 and 8 720Nimhs at 9.3oz. but got crushed by my dog in the back seat of our car. Yes, we still have and love the dog mostly because his destruction allowed me to upgrade the power system and build the plane to be more durable ;-)

Here's the third to be powered by a Hacker B20-31s on 3 1200Mah Lipos at 10.5oz. Wing loading will be in the neighborhood of 15oz./s.f.

Do you think it will fly?
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Old Apr 09, 2003, 12:58 PM
Balsa Flies Better!
Stamford, CT
Joined Oct 2000
6,704 Posts
You've got perserverence

Mars

Gotta give you credit for sticking to it- you must love that airplane (and your dog)

I'm glad to hear the M-100 worked. These days, I'm really liking that motor on a 2 cell 1020 li-poly pack- that's a lightweight approach.

Don't know much about the Hacker- think your battery selection is fine though- isn't that lighter than the 8 cell 720s? Another motor option might be a geared Astro 010 or one of the new Razzors- might be lighter than the Hacker. Are you looking at an 8" prop?

Good luck with this one.

Sam
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Old Apr 09, 2003, 01:08 PM
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mars's Avatar
San Francisco, CA
Joined Jan 2002
577 Posts
Thanks Megowcoupe,

The 3 Lipos are about .5 oz. lighter than the 8 720s, but the motor weighs in at +/- 3oz. with the MPJet prop adapter and a CC Phoenix25. The motor itself is only 1.8oz.

So, the new power system accounts for the extra weight of Mark III vs. Mark II.

I have tested a GWS 8x6 prop on the motor setup and I draw about 5.5-6 amps at full throttle static. WOW does this little motor pull!! I have no thrust numbers yet but will as soon as I put the plane together.

Do you think the wing loading will be too high to fly or do you think It will fly and land fast? The wing loading is comporable to a Jim Ryan bird but the size is smaller. Any educated guesses out there?
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Old Apr 09, 2003, 06:03 PM
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Gerald's Avatar
Joined May 2000
3,335 Posts
I think it will be a little bullet and will be a handfull to handle . I don't think I'd want to fly it. The stall speed will be fairly high for a plane this size at about 18-20mph. Motocalc says it "will require the undivided attention of an expert pilot". Also your pitch speed may be too low if you are using the 4:1 geared version of the Hacker.

It's gonna be way overpowered with your setup. At 1.8oz you must be using the 4:1 geared Hacker. the direct drive unit is only 1.4oz.

If you are determined to have a brushless in it you could probably use the same motor direct drive, a smaller prop - say about a 5x4, and a two cell battery to save a lot of weight and still have high performance. You would also be better off with the CC Phoenix 10 as it is much lighter too.
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