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HomeAircraftHelicopterAntiques or Out of Business › WHOS STILL FLYING THERE KAVAN JET RANGERS?
01-24-2010 08:20 PM  8 years agoPost 1
huey nut

rrApprentice

DRIPPING springs texas

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looking for pics fo your rangers and how long has she been flying as well as any tips you can give me for my restoration thanks guys

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01-25-2010 12:20 AM  8 years agoPost 2
heli_headcase

rrKey Veteran

Hovering around Atlanta

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I'll start...
Got a 1974 KJR that's flying about as good as the stock wood blades and period Supertigre G.60 blue-head will allow.

Control system is converted over to eCCPM to eliminate the mechanical play inherent in the mechanical mixing system. Using 90deg mode, servo in the front and back and one side of the swash.

Head speed is pretty constant at 1050rpm and the available power is marginal at best for the heli's overall weight.

Flybar paddles are the 'Expert' wood units with no additional weight. The Bell-Hiller rotorhead update and washout are installed. I don't think I ever measured the collective pitch range - just set it for what looked 'right'.

Did this help?


HHC

So many heli's - too little time...

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01-26-2010 01:01 AM  8 years agoPost 3
RAK402

rrElite Veteran

Alhambra, CA

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I still have mine, but it will never fly again (not by me anyway).

Team KBDD/Compass Team Manger/Experience RC/Team JR Americas/WR Field Rep

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01-26-2010 11:20 PM  8 years agoPost 4
raptorgary

rrApprentice

lima ohio

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i have one and i am considering converting it to electric and fly it i am not sure what motor set up i will need maybe someone while chime in and give me some suggestions
gary

team wildcat fuels

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01-26-2010 11:38 PM  8 years agoPost 5
heli_headcase

rrKey Veteran

Hovering around Atlanta

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The conversion components will depend mostly on what you plan on using for battery packs, cell count in particular. Then pick your desired head speed. I say 1200rpm is about right. I forgot the gear ratio so if someone provides that number the rest is a snap to compute.

Use 10S (2 X 5S packs in series), around 4000mah LiPo for convenience and cost effectiveness. Should give you easy 10min flights.

But let's just say the engine-to-main rotor gear ratio was 12-1.

At 1200rpm head speed, multiply that times the ratio of 12 and that's going to give the running motor rpm of 14,400. Divide that by the battery pack voltage of 35V (nominal) and that gives the rough Kv of the motor, or 411 rpm/volt. But now multiply that times the basic efficiency correction factor of .8 and you get a real motor Kv of 329.

A smaller pulley should be selected since that's a somewhat low Kv for what's commonly available in heli brushless motors.

Or you can drop the cell count to 8S (2X 4S packs in series) for a nominal pack voltage of 28, divided into 14,400 which after all is calculated lets a 400Kv motor work well. Lots of those around.

You need to check that gear ratio to make sure this is a real calculated ratio and my numbers would fit.

That's a start anyway. Mounting the motor securely should be easy if a flat plate is bolted to the bottom of the engine mount frames. Yeah, I like that

Have fun!


HHC

So many heli's - too little time...

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01-26-2010 11:58 PM  8 years agoPost 6
raptorgary

rrApprentice

lima ohio

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thanks steve that gives me a place to start

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01-27-2010 06:30 AM  8 years agoPost 7
vrhc

rrApprentice

East Yorkshire - England

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Kavan Electric
Slight ammendment to the calculations needed. When working backwards you divided by the efficiency as the Kv achieved is always less than the rated motor kv at no load i.e.

411 / 0.8 = 514 rev/volt

From this you will need something like a Plattenburg Orbit motor.

Joe

www.vrhc.co.uk - The Da Vinci Mode

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01-27-2010 06:57 AM  8 years agoPost 8
heli_headcase

rrKey Veteran

Hovering around Atlanta

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Whoops! "Backwards Maths"
Thanks Joe for making the correction. I've done these calculations so many times but usually starting with the available motor and finding the appropriate gearing to match.

There are many ~500Kv motors out there so take your pick. This is for 10S by-the-way. Make it a 600Kv motor if 8S is used. Or modify the size of the motor pulley as needed...


HHC

So many heli's - too little time...

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02-16-2010 05:01 AM  8 years agoPost 9
chuck nowell

rrVeteran

beaumont texas

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retired after dad passed away in 1993.

chuck

E-Kavan
trex800
trex700
ma razor600
team visa

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