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Old Mar 11, 2009, 02:55 AM
So Cal FPV Aviator
EyeFlyPlanes's Avatar
USA, CA, Santa Clarita
Joined Feb 2008
3,575 Posts
Quote:
Originally Posted by GryphonRCU
EyeFlyPlanes,

Measure as accurately as your ruler and eyes allow.

See if you like mm or 1/16"...whatever works for you just keep it line up well so the ruler does not move during your work....look at it square on as you read (not from above or...)

With fancy equipment you can measure angles of throw (best) but measuring with a ruler works for me just fine.

Double check each number and then write it down before going to next one.


Good luck,

Gryphon
Will do
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Old Mar 11, 2009, 04:12 AM
Xtreme Nut
Kuala Lumpur, Malaysia
Joined Oct 2005
2,046 Posts
I only done that sort of a launch with my MJ, that baby will torque more than the FJ.

Gryphon ... we got over 500 pages! I have not searched yet, hehehehee
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Old Mar 11, 2009, 05:35 AM
Ook!
skaffen's Avatar
New Zealand
Joined Aug 2007
1,496 Posts
Has anyone tried a cheap gyro to prevent torque roll? Can't say it's an issue for me, but I know a few FPV guys are using them in Easystars.
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Old Mar 11, 2009, 05:49 AM
Xtreme Nut
Kuala Lumpur, Malaysia
Joined Oct 2005
2,046 Posts
skaffen ... a bit of right aileron on launch helps a lot
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Old Mar 11, 2009, 07:04 AM
Xtreme Nut
Kuala Lumpur, Malaysia
Joined Oct 2005
2,046 Posts
I need some help here. You guys doppler things all the time. Can someone assist me and lemme know how fast this baby is doing? Its about 30*C here or 86*F with a humidity of about 90% I think. Appreciate the assistance!

Viper 500 GP
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Old Mar 11, 2009, 12:01 PM
zoom zoom
gotboostedvr6's Avatar
USA, NJ, Mt Laurel
Joined Oct 2007
3,691 Posts
Both got 97 mph.

The runs need to be done directly over the camera with it being 100% stationary, not following the model. Also The run has to be less then 35 feet off the deck with a 200 foot approach and 200 foot fly by with out pulling up the whole time.

If you do this correctly next time your speed will be higher
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Old Mar 11, 2009, 06:48 PM
The Kid
Thekid3418's Avatar
Detroit, MI
Joined Dec 2007
2,587 Posts
Quote:
Originally Posted by tIANcI
I need some help here. You guys doppler things all the time. Can someone assist me and lemme know how fast this baby is doing? Its about 30*C here or 86*F with a humidity of about 90% I think. Appreciate the assistance!

Viper 500 GP
My dodger with a ST-45 on a ultrathrust muffler with a 9x6 was faster then all the Vipers out there at our last club race. I was at 122 mph coming out of turn 1, and i would say i had about 5 mph on everyone else. As long as you have a good strong .40 you should be up around 100-110 if i had to guess, so GB doppler is pretty darn close by my guess
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Old Mar 11, 2009, 08:36 PM
Xtreme Nut
Kuala Lumpur, Malaysia
Joined Oct 2005
2,046 Posts
GotBoosted .... yeah the cam should not follow the plane. Okay I shall try to get it done properly and then see how it goes. Camera stationary, plane comes in from 200', 35' off the deck and out 200' later. Thanks a lot guys!!!
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Old Mar 11, 2009, 08:43 PM
zoom zoom
gotboostedvr6's Avatar
USA, NJ, Mt Laurel
Joined Oct 2007
3,691 Posts
also dont forget directly above the camera not off left or right... if the camera guy stands behind you it is alot easier
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Old Mar 11, 2009, 09:58 PM
Xtreme Nut
Kuala Lumpur, Malaysia
Joined Oct 2005
2,046 Posts
I got that BoostedMan! I shall fly above me, maybe get a tripod for the cam since the cameraman will feel iffy with that baby coming in at 35'. Hahahahaaa ...

Anyways, back to topic ... looking at the speed of my Viper, I will then now say that my FJ on 4S and the HET 2W-25 turning a 4.75x4.75 is about that speed. Hence, potentially about 100-110 mph. But that feels really slow when you are the pilot!
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Old Mar 12, 2009, 12:28 AM
What smoke?
Lostlad's Avatar
SoCal
Joined Feb 2008
279 Posts
Once you get really comfortable flying a plane you tend to get a bit over confident and make mistakes. I was doing some high speed passes down the street next to some trees and all was well.....

Once I lined it up for a landing I came in a bit hot and didn't see the trees till it was too late and well the tree won. I tore thought it like foam - oh wait the plane is foam. I think it was going over 60 when it hit. Oh well I got a good deal on a new frame and going to start the build tomorrow.

Lostlad
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Old Mar 12, 2009, 12:57 AM
Xtreme Nut
Kuala Lumpur, Malaysia
Joined Oct 2005
2,046 Posts
Lostlad you are not the only one! Hahahahahaa ... its fo familiar ... that is why I sometimes limit my flight times. Once its more than 5 mins the devil comes out and the plane is in smithereens
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Old Mar 12, 2009, 02:56 AM
So Cal FPV Aviator
EyeFlyPlanes's Avatar
USA, CA, Santa Clarita
Joined Feb 2008
3,575 Posts
Hey guys,

Ok flight update on my unpredictable funjet. So today i decided to go through everything on it with a fine tooth comb and made sure every bit of it was perfectly aligned and straightened.

Apparently the trailing edges, right next to the motor, were a bit tweaked. So i cut them loose, re aligned everything and reglued everything in the most perfect way the human eye could notice.

I also put carbon strips across the entirety of the trailing edge so everything was Straight as an arrow.

So today when i took it out and I pulled down stick for up elevator, it did up elevator! No twisting, nothing. It was the airframe and not the servos. It flew straight and true.

But the torque roll thing still seems to be an issue. Funny though i was talking to another guy there with his funjet that he has setup on a 4 cell & said when hes got it @ full throttle his plane will torque roll right as well. And he would describe the exact same feeling as i did, the torque was so strong he would hit full right stick and it would just barely turn.

So funny how that works. Any other remedies for this? I really love my 6x5.5 prop & I will never go back to a 4.75x4.5 again (no thrust).
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Old Mar 12, 2009, 03:08 AM
zoom zoom
gotboostedvr6's Avatar
USA, NJ, Mt Laurel
Joined Oct 2007
3,691 Posts
A 6x4 would exert 28% less tq to the airframe and produce 20% more thrust give or take.

or you could try a 5.2 x 5.2 graupner
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Old Mar 12, 2009, 07:22 AM
Gone Flying.
ChrisWNY's Avatar
Western NY
Joined Nov 2006
2,401 Posts
Quote:
Originally Posted by EyeFlyPlanes
Hey guys,

Ok flight update on my unpredictable funjet. So today i decided to go through everything on it with a fine tooth comb and made sure every bit of it was perfectly aligned and straightened.

Apparently the trailing edges, right next to the motor, were a bit tweaked. So i cut them loose, re aligned everything and reglued everything in the most perfect way the human eye could notice.

I also put carbon strips across the entirety of the trailing edge so everything was Straight as an arrow.

So today when i took it out and I pulled down stick for up elevator, it did up elevator! No twisting, nothing. It was the airframe and not the servos. It flew straight and true.

But the torque roll thing still seems to be an issue. Funny though i was talking to another guy there with his funjet that he has setup on a 4 cell & said when hes got it @ full throttle his plane will torque roll right as well. And he would describe the exact same feeling as i did, the torque was so strong he would hit full right stick and it would just barely turn.

So funny how that works. Any other remedies for this? I really love my 6x5.5 prop & I will never go back to a 4.75x4.5 again (no thrust).
I had a similar problem with one of my FunJets - I'd get a lot of torque roll on hand launches, but later found out that I hadn't double-checked lateral balance, and sure enough, re-balancing fixed the issue. The airframe doesn't need to be 100% true to fly straight, some things can be fixed by balancing to off-set any frame imperfections. Carbon fiber rods definitely help also, I've seen some run them along the back side of the wings by routing channels with a dremel or soldering iron.

Depending on the motor/power setup, a 4.75x4.5 can provide plenty of thrust, but you need the RPMs to make up for the smaller prop size. It may be that your motor was better suited for a slightly larger prop size, but make sure you check Amp draw to be on the safe side. Generally, hotter wind motors (1.5-2 turn) are designed to spin smaller props at higher RPMs, whereas the higher winds are built to spin a larger prop for more thrust but at lower RPMs.
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