OK - gonna try the Cox Viper one more time.... - Page 2 - RC Groups
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May 21, 2001, 09:47 AM
Registered User
Steve McBride's Avatar
I know I am not the others, but.....

Mine was way over 109 grams and flew fine. I used CS-10's, GWS direct on stock Viper prop and 6x110 cells (the ones included in the viper free flight setup), feather receiver and Wattage IC-55 ESC and all flew great.

Where do you have your CG set at? I tried to balance mine where the free flight balanced at whic I think was just ahead of the spar. Placing the servos just behind the wing saddle, the receiver just behind those, the battery up front and the ESC just behing that should get you close. On 6 cells mine came out a bit tail heavy. On 8 cells it balanced better but the motor cooked after a couple of flights.

Good luck and let us know how it goes!

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May 21, 2001, 11:35 AM
Registered User
Visited 3 Wal-Mart's in my area and came up empty. They all had the highway patrol plane by Cox, but none had the Viper. When I asked, they told me that they do not stock it! Has anyone seen it online anywhere? I checked the Wal-Mart site and did not find it there either. Ideas?

May 21, 2001, 12:56 PM
Registered User
Well I got finished with my Viper and used a 9v nicd for power(since it is actually a 7.2v). I have the GWS flight pack and the DX-A power unit installed via direct drive.
On the first toss nose down. Second toss she went down nose first again and cracked the fuse in front of the wing. I can't get it to stay up in the air. I have it balanced just behind the wing reinforcement spar.

I am new to microflight but not to rc aircraft. I timed the duration of my setup to last 1.20 minutes on the bench with the throttle fully open before the motor powered off. Is this normal?

Frankenfoamy, how long is you viper flying? I had a 50mah nicad pack in mine that only ran the motor at full throttle for about 30 seconds. What is wrong with my setup?

The plane fully rigged is weighing in at ~120 grams.


May 22, 2001, 12:02 AM
Mike Swan
Hey Guys, Tower Hobbies finally has the Hobbico free flight P-40,20"span for $15.00 looks very similar to viper.
May 22, 2001, 12:05 AM
Addicted Member
miker's Avatar

Regarding CG, I saw an earlier post (I think from you) which recommended a CG just forward the spar. I think that is where I had the balance when it fell, I mean flew .

Still need to bench test the power system.

May 22, 2001, 01:25 AM
Registered User
Answered my own question:

Your Wal-Mart doesn't carry the Viper?

May 23, 2001, 09:49 PM
Registered User
jimmyray's Avatar
I buolt one too, all per suggestions in the Microflight newsletter. I got is to glide right (eventually) and tried powed up with 6x50 nicads. It would tip stall and dive, or roll bad and dive, but after lots of nose jobs, it has to be replaced. I'll try it again, but maybe I need more experience...

Having great fun with my Pico Fuse, though!
May 23, 2001, 09:58 PM
Blew out my flip flop
David Hogue's Avatar
For those who might be looking for a Viper, I have one for sale:

I also have one of those Acro bipes that has been talked about over on the microflight board...I might be talked out of it, also!!

May 26, 2001, 01:23 AM
Addicted Member
miker's Avatar
Another flight this morning. Not completely successful, but much closer. Previous flights have injured this Viper, making flights unpredictable. But I did see some signs of flight this morning until I hit a tree, the house, the rock wall, etc.

For my flights this morning, I tried 7x50mah cells instead of 6 and I think that helped.

I also removed the charger/switch panel, which turned out to be rather heavy. With additional wiring my panel weighed 9g I think. I can't find it now, but I think that was it.

Unfortunately this plane has had it. Fortunately there is a Walmart down the street.

May 26, 2001, 12:23 PM
Addicted Member
miker's Avatar
oops, the charger/switch panel with battery leads is 5 grams. Sorry for the exageration.
May 26, 2001, 12:41 PM
Strange Plane Central
frankenfoamy's Avatar
The aileron conversion weighs 123 grams ready to fly with 7 cell double time NiMHD.
The wing reinforcement did three things
1. stiffened wing which was needed to prevent aileron binding.
2. removed under chamber from wing root area which help it fly faster without ballooning.
3. the wing tip has relatively more chamber reducing tip stall

( article at http://phreak.mine.nu/drblott/RadioControlProjects.htm )

Let me say something about the motor.
At least one pilot thought the motor I referred to was a 280. ( I think a LHS lead him astray) way too heavy.
Also not all Mabuchi 060 are the same.
The one I used came out of a DX gearbox which apparently has better windings and maybe magnets than the STD.
May 31, 2001, 05:08 PM
Strange Plane Central
frankenfoamy's Avatar
The COX VIPER P-51 kits apparently are not available everywhere.
I bought a few and will sell them at my cost. ( Hey, I got one free for buying a bunch)
check my web page for details.

They are a blast to fly!

Insanediego AMA#02241 http://phreak.mine.nu/drblott/RadioControlProjects.htm
May 31, 2001, 05:15 PM
Registered User
Steve McBride's Avatar
Local wal-mart has about 6 of them in stock at $15.00 each. Perhaps order through walmart.com?

Jun 01, 2001, 11:47 AM
Strange Plane Central
frankenfoamy's Avatar
Last night I had a long IM session with a VIPER builder in the UK.
He is using a S280 motor!
He hopes to have a flight report within a week. Stay tuned.
Jun 01, 2001, 08:32 PM
Strange Plane Central
frankenfoamy's Avatar
Possible weight savings.
I did not split the fuselage in half as some people did. Glueing it back together adds weight.
I used polyurethane glue.
Also I used a GFS esc. one gram plus 4 grams of wires. (three times too long) so I can lose three grams there.