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Nov 10, 2006, 10:50 PM
Registered User
hardlock's Avatar
Help!

Carbon Mix-Master flies (sort of)


Here's my VTOL project.

I wanted a heli for airplane pilots so went with TX mixing using flaperons for the main motor ESCs slaved to the throttle stick. Still playing with the mixes but differencial thrust is working okay for roll. Too well actually as I've managed to flip it on it's back a number of times from a 2" hover!

Tail motor is for pitch mostly with very little lifting being done based on a slightly tail heavy CG on the mains centerline. Maybe an ounce or two. Mixing is being tested both with throttle combined with mains as well as separate off the elevator stick only.

I also want to try using it as a pusher with the CG slightly forward but the TB-9 seems to only want to run the motor one direction off the stick no matter how I reverse the travel direction on the elevator stick! Maybe a fixed throttle phx-10 will allow it?

The tail motor is setup for tilt with a HS-55 for yaw and it seems to work pretty good from the few 2" high test flights done so far.

Specs are:

Span (prop disc)= 24" - length=17.5" to back of tail rotor disc.
Weight: 10-12oz depending on pack(s)

Motors: Mains- 2) Komodo 2204-17 with Max products 10x4.5 counter pitched props
Tail: Feigao 1208436L w/ 3x2 dd

ESC: 2) Phx-10 for mains with fixed throttle setting
Tail: TB-9 (needs to be Phx-10 also for fixed throttle I think)

Pack: 2S 800-1250 or larger - getting ~2:1 power to weight I figure as it wants to hover at about half throttle.

I started out thinking I needed about 2000mAh for amp requirment and good duration and connected 2) 1250 2S packs together in parallel for 2500mAh. Forgot once to connect the 2nd pack and was flying it fine on one so got to ditch a couple ozs right away to help keep it light for testing.

Now down to the problems with it. I'd hoped to not need gyros but it appears that it will be a real handful to fly without them. Possible maybe in the right hands but not in mine.

QUESTION: What's gyros are available for pitch and roll that will work for this bird? Any multi ones available yet? I was reading in some old tri-copter posts they were in the works.

I assume 3 separate cheapos may do it but am concerned that the roll ones may want to fight each other in the mixing? I know little to nothing as to how they work or get setup.

I'll try to get a vid up soon but it will be very short at this point.
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Nov 11, 2006, 08:07 AM
Registered User
v22chap's Avatar
hard lock
Nice looking tri copter .. like the tail control unit ..

The gyro has to be a slow responding type on the airplane prop vector units .. As VTOLMAN has pointed out .You must be able to keep turning the gyro around and round by hand and the servo arm move about to its extreme throw and stay there . If it returns right away it will make the motor control jerky and only make the control problem worse.

ACT Europe make a double input/ output gyro for about 99.00 ,,but you have to order it from Germany and you have to have a website translator too as it is written in German.
The horizon pz -200 revolution gyro also seems to work o.k. when running the above test ... VTOLMAN used arcamax ,,but they are no longer produced.

You should be able to use two together as that is what VTOLMAN did .. search for his project as I remember there was a wiring diagram on how to hook up the Veetail mixers and the gyro units.
Good luck
Larry
Nov 11, 2006, 08:08 AM
Square-rigger
meatbomber's Avatar
Now that's a cool plane can you show some more detail pictures please ?

i'm planning on doing a similar configuration
Nov 11, 2006, 04:47 PM
Registered User
hardlock's Avatar
Quote:
Originally Posted by v22chap
The gyro has to be a slow responding type on the airplane prop vector units .. As VTOLMAN has pointed out .You must be able to keep turning the gyro around and round by hand and the servo arm move about to its extreme throw and stay there . If it returns right away it will make the motor control jerky and only make the control problem worse.
Larry
Thanks Larry, I've read most of his posts. Isn't that problem only related to moving motors that vector the thrust? My mains are stationary so only differential thrust needs to be tamed for roll and tail rotor RPM for pitch. The pitch gyro should be easy enough since it has no mixing but am concerned about the TX mixed mains needing separate gyros and which type as well as if they won't fight each other.

Everyone said this wouldn't be easy or cheap. Guess I was dreaming thinking I could just fly away with little effort.

MEATBOMBER: I'll get you some more pics. The construction is very simple with no wood or even glue used. All the frame is .08 rod plugged together with Superthene tube elbows or Ts make from a length with a hole poked in it and the rod forced through. Motor mounts are attached with wire ties and that's about it. The tail rotor is attached with a sliced open kite rubber T and more wire ties with a short length of .157 CF tube extention pivoting in some poly tube again wiretied to the frame. The connection to the servo is a piece of rubber windshield washer hose plugged directly onto the servo hub.
Nov 11, 2006, 09:54 PM
Registered User
v22chap's Avatar
Code:
Isn't that problem only related to moving motors that vector the thrust
I haven't done a lot on this type ,,but I believe that even the differentail thrust will need the slower type gyro's ... anything that isn't as fast as a tail rotors control needs the slower type. Actually ,,my collective v-22 needs the slower gyro ,,if I try to use heading hold on the ACT ,,, it gets really twitchy.

The mix in the TX of the throttle and roll will have to go into the ACT or futaba dual input / ouput gyro as it will not work with two seperate gyro's for the ESC's differentail . I think
I will have to try that one to see for sure. I did one engine vector with just one gyro on one motor and it was flyable.The one side kind of play catch up with the other but it was slow enough to control in side my garage and they were IC motors.
Nov 11, 2006, 11:41 PM
Registered User
hardlock's Avatar
Cool - Any results greatly appreciated! Before I layout a bunch of $ on gyros, I have a friend that is going to loan me a couple to test with. With the right differential on the main motors, maybe I can get away with just a single on the tail pitch one.

Here's some details of the framework. The fabric triangle panel I already had for another project that never "took off". I just rubber banded it into the frame.

The construction method is like playing with tinkertoys. Start with a pile of fittings and rods and make something. Looks complex but the entire frame less gear only weighs 1.5 oz and is very strong. Best part is I can slide things around to change dihedral, etc.

Speaking of dihedral, I would think that some added to the prop planes would help stability but mine are about level for now.

Any ideas on this? I notice some of the twin gyrocopters use some as they are r/e designs I suspect. However if you look at the twin heli on the right in the Tech Model Products sponsered ad above, it has lots of anhedral? What's up with that?
Nov 12, 2006, 03:52 AM
Square-rigger
meatbomber's Avatar
The heli with the anhedral on top is a Kaman design that uses intermeshing rotordisks.. so you need to tilt the diks to get clearance from the blade to the other rotorhead

I really really like the way you made that airframe! I only found Superthane as a product on the web, but i think really any thin plastic tube will work as long as it's stiff enough rigth ?
Nov 12, 2006, 04:22 AM
Registered User
hardlock's Avatar
Oh, that explains the angles on the blades....Doh!

The Superthane isn't stiff but is like silicone fuel tubing that's rubbery and sticks well to the rods w/o glueing.

Don't know what other types or sizes are available of other materials, but the more rubbery in texture the better it sticks. We used to use just hardware store clear vinyl tubes and CA them but they only make those so small in diameter.

We use the Superthane extensively in the Carbon Traveler Convertible 3D biplane kits. (BTW - we have small amounts on our website as spare parts for the Carbon Kestrel. It's in 16" lengths as a pair of .063 ID and .125 ID sizes if you want to try some.)

Love the stuff as you can slide the rods in easy but you have to release them with a thumb-nail like the old Chinese finger traps.

Like I mentioned you can "breadboard" a frame and change it around until you get it like you want and then CA all the fittings in place if needed. Our CTC bipe can be torn down for flat travel in a couple minutes using the stuff.

Ends up shock mounting all the junctions as a bonus! See the CTC plans here for more fittings you can make with pics if interested in using this method:

http://www.acesim.com/temp/plans/

(the "CTC_construct_final_01.2.pdf" file)
Nov 12, 2006, 07:29 AM
Registered User
v22chap's Avatar
Hard lock
The V-22 also uses 4 degrees or so of anhedral ...the whole nacelle points out ...on mine I just made the cyclic point out about 3 degrees and it always seemed to help .Didn't know that I was doing it like the real one until the trip to see the full scale one at Pax River ,, I just knew from testing that it helped some,,can't explain why it helps ,,it just can be felt when flying it.
Nov 12, 2006, 01:56 PM
Square-rigger
meatbomber's Avatar
Awesome thanks hardlock! That's just like a little model experienters kit i'll hgave to give that a try !
Nov 12, 2006, 02:51 PM
LSF 004 - AMA 5055
bobandris's Avatar

Gyro Recommendation


hardlock,

Based on trying a lot of different combinations and gyros for my TriCopter; here's what I found to be the best for both working correctly and the lowest price. BTW, I used a 'heli' setup of 120deg CCPM, just to make all the mixing transparent.

Three GWS PG-03 (one between each CC Phoenix 10 ESC and the RX), one Futaba GY-240 between the single "yaw" servo (Hitec HS-56HB) and the RX. BTW, I'm using three Feigao 12mm (1208436L) motors in 8.6:1 IPS-C gearboxes, swinging GWS 10x4.7-SF props. I tried the hotter wind Feigaos 1st, but since there is no forward airspeed, they got REALLY hot. Battery is a 3S1P ThunderPower 1320. Thrust-to-weight is about 2.75:1. It's really hot, vertically!

As to setting the gyros, I found that full gain on the PG-03s and 75% on the GY-240 was the best. Hope this helps.

Bob
Nov 12, 2006, 04:22 PM
Registered User
v22chap's Avatar
Bob
Cool idea on the 120 heli setup idea ,,never gave that a thought.
Nov 15, 2006, 12:49 AM
Registered User
hardlock's Avatar
Here's a rough video of it being test flown w/o gyros. Now I see why they are needed!

https://www.rcgroups.com/forums/showthread.php?t=597039

Thanks for the info bobandris and v22chap. I'll have to head in those directions and report back. I just got a JR G410T installed and a quick test shows with some tweaking, pitch should be controllable now.

bobandris - No problems with the roll gyros fighting each other?
Nov 21, 2006, 10:48 PM
Registered User
hardlock's Avatar
I've got the JR gyro installed and it flies much better. Still having trouble in roll but have another gyro ordered for it. Here's a quick clip of the results with a little practice:

https://www.rcgroups.com/forums/showthread.php?t=600305
Nov 24, 2006, 07:28 PM
LSF 004 - AMA 5055
bobandris's Avatar
Sorry for the late answer - haven't been on in a week or so. The "roll" gyros don't really fight each other. They are oriented to control each motor's moment perpendicular to the line from the motor to the CG; not roll, per se.

Bob


Quote:
Originally Posted by hardlock
Here's a rough video of it being test flown w/o gyros. Now I see why they are needed!

https://www.rcgroups.com/forums/showthread.php?t=597039

Thanks for the info bobandris and v22chap. I'll have to head in those directions and report back. I just got a JR G410T installed and a quick test shows with some tweaking, pitch should be controllable now.

bobandris - No problems with the roll gyros fighting each other?


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