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Old Nov 18, 2009, 09:10 AM
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Swansea, Massachusetts
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Quote:
Originally Posted by Dave Barrow View Post
Yeah, my HK order shows shipped.
signguy, can you give me the dia. of the 750 motor mount base please? I have the body and arms cut and bolted together, I can start making the yaw mount and mount discs for the other two motors. I'll post pics tomorrow, been working overtime every day so I don't have a lot of build time in the evenings. I should be able to get more done this weekend.
Dave

The base is 1 3/16" and the motor bell is 1 5/8"
You'll need to make your yaw mount longer in the front to allow the motor bell to clear the servo.
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Old Nov 18, 2009, 09:59 AM
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My new copter is using no motor mounts - Just a zip tie through the bolt holes and around the boom - So far it has been very solid and doesn't slip at all - My hope is that in a crash it would either break free or move a little to absorb some impact. Also very easily field repairable - Anyone here knowledgeable in programming? I would like to use one of these for my tricopter Lots cheaper than gyros and I can get them locally - Makes lots of sense if you think about it - http://www.rcgroups.com/forums/showthread.php?t=1143580

Mike
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Old Nov 18, 2009, 10:03 AM
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Quote:
Originally Posted by cdi3d View Post
My new copter is using no motor mounts - Just a zip tie through the bolt holes and around the boom - So far it has been very solid and doesn't slip at all - My hope is that in a crash it would either break free or move a little to absorb some impact. Also very easily field repairable - Anyone here knowledgeable in programming? I would like to use one of these for my tricopter Lots cheaper than gyros and I can get them locally - Makes lots of sense if you think about it - http://www.rcgroups.com/forums/showthread.php?t=1143580

Mike
I saw that too Mike.
I would love to build something like that. He is going to use the nunchuck's accelerometers with the gyros too. I may try to learn the programming if things slow down this winter.

Bob D
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Old Nov 18, 2009, 10:43 AM
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Hey all
Another update on carrying ability.
I just came in from flying around with a 6" length of 2x10 strapped to the bottom of the copter. I was trying a 4 cell a123 2200 mah pack that weighs 12 oz.
here are the weights

tri empty 28.5 oz
tri w/ battery 40 oz
Block 24oz
all up weight 64 oz

It can fly safely at this weight, you have to turn the gyro gain down a bit.
I only flew for a couple min, but can tell you, you are not going to fly long at this weight. Maybe 4 min at 2200 mah. You also have to plan your descents, and start to power up a little higher than normal. Also had a complete motor out while landing ( without the weight) I throttled down too much, and the gyro shut one motor off trying to stabilize the copter in a turn. I hit the power and flew away from about 10 ft up scared the heck out of me.

Bob D
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Old Nov 18, 2009, 10:49 AM
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That is amazing!!! 24oz - Almost doubling the weight of the copter - Great job Bob! Now get busy on that WII controller!!! LOL - Thanks

Mike
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Old Nov 18, 2009, 01:42 PM
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I've been using Golf club shafts for many years for tailbooms on sailplanes and on my Eyespy Photoplanes. they are relatively light and stiff.
I just trimmed up three 20" butt ends for a tricopter. They are from Cobra 34" stiff shafts. each piece is 1.35 oz., making a total of 4 ounces.

There are a few interesting things about carbon shafts. They seem to use a constant amount of carbon fibre throughout the full length.
As they are tapered from 0.6" to 0.37" this means that wall thickness increases appreciably towards the slim end. This is likely done to obtain the required springiness and stiffness. The result is that the centre of gravity is almost only a little bit off the half way point of the shaft.
The thickest end is constant diameter or the first 4.5 inches and this can be useful in lining up everything in the base plate mounting.

One important thing to take into account is that unidirectional fibres are used, with no "cross grain " fibres. This can lead to splitting of the tube if not suitably reinforced around the drilled pivot hole. A 2"long dowel should be fitted internally and if possible, wrapping with kevlar tow around the pivot will help in preenting splitting.

I want to thank everyone on the thread and my order hasgomne to HobbyKing.

john
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Old Nov 18, 2009, 05:27 PM
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I just tried some 12x6 GWS props on mine and really like the way it handlles - lots more lift - at lower rpm - Can't wait to get it outside -

Mike
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Old Nov 18, 2009, 05:32 PM
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Quote:
Originally Posted by John O'Sullivan View Post
I've been using Golf club shafts for many years for tailbooms on sailplanes and on my Eyespy Photoplanes. they are relatively light and stiff.
I just trimmed up three 20" butt ends for a tricopter. They are from Cobra 34" stiff shafts. each piece is 1.35 oz., making a total of 4 ounces.

There are a few interesting things about carbon shafts. They seem to use a constant amount of carbon fibre throughout the full length.
As they are tapered from 0.6" to 0.37" this means that wall thickness increases appreciably towards the slim end. This is likely done to obtain the required springiness and stiffness. The result is that the centre of gravity is almost only a little bit off the half way point of the shaft.
The thickest end is constant diameter or the first 4.5 inches and this can be useful in lining up everything in the base plate mounting.

One important thing to take into account is that unidirectional fibres are used, with no "cross grain " fibres. This can lead to splitting of the tube if not suitably reinforced around the drilled pivot hole. A 2"long dowel should be fitted internally and if possible, wrapping with kevlar tow around the pivot will help in preenting splitting.

I want to thank everyone on the thread and my order hasgomne to HobbyKing.

john

The golf club shafts are interesting. Are they available at a fair price ?
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Old Nov 18, 2009, 05:34 PM
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Hobby City should pay a commission on this thread. I just ordered gyros and motors and props and........
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Old Nov 18, 2009, 05:59 PM
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Quote:
Originally Posted by cdi3d View Post
I just tried some 12x6 GWS props on mine and really like the way it handlles - lots more lift - at lower rpm - Can't wait to get it outside -

Mike
Maybe I could lift even more!!!
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Old Nov 18, 2009, 06:26 PM
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I got a bundle of shafts on Ebay about six years ago. Have not been looking for them lately, but there should be some about.
Perhaps a visit to your local golfing repair man would spring some at rock bottom prices.

John
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Old Nov 18, 2009, 07:42 PM
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Bob - I bet you could lift another 5-8 oz with these maybe more - I was so surprised at how well it flew with them very stable - Any ideas why I have to keep trimming while in flight? The GWS props are by far the lightest I have found - The APC's I had on there were to heavy One thing I did have to do is adjust my gain way up to around 20 for hands free hovering with them (this was on the trainer of course) Might go try to lift some weight-

Mike
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Old Nov 18, 2009, 08:05 PM
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Look for local thrift stores like Goodwill. They usually have a bunch of clubs, some with graphite shafts. I've never paid more than $1.50 for one! Strip off the grip, cut off the head, and have fun.

Rob D.
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Old Nov 18, 2009, 08:20 PM
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Ky
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Mike try turning your gyros on and let them warm up for 5 minutes and then restart them before flying, worked for a Telebee gyro I had on my Guru-Z. Moving from a warm house to the cooler/warmer temperature outside can cause this also, let it sit outside for a while to let the gyro components acclimate to the air temperature. Make sure your tri is sitting as level as possible before turning on and do not move it until all gyros have fully initialized.

What kind of amps do the 12x6 props pull on the T750's? How warm are they get after a flight?
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Old Nov 18, 2009, 08:43 PM
Flying with the eagles
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Eagle's nest
Joined Nov 2008
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Hi signguy,

I'm very impressed by your tricopter build thread. I really like the low cost and simplicity of it. Simple things are the best.

Currently I'm flying my camera on an EPP eagle and would like to explore putting my camera on a tricopter for closeup and indoor shots. Some thoughts in my mind before I take the plunge.

Protection
How reliable is it to carry a 7 oz (200 g) P & S camera.
Any way to make it crash proof.
Would an extended heliopter style skid help.
How about those carbon rods with balls at the ends they use for helicopter training.

Control Stability
You mentioned there was a sudden accidental climb, that nearly crashed your tricopter. Anyway to prevent that. Was it due to too much weight overloading the power system. Would lower kV motor with larger props help. How to calculate the maximum loading for a tricopter?
Do tricopters autorotate when out of juice?

Camera
Regards to framing the shot, any way to steady the rolling and yawing. How about video downlink or a laser pointer for aiming.

Components
For which components is it critical to buy a good quality one? e.g. gyros, servos, esc.
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