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Mar 22, 2013, 09:58 AM
Airplane and Heli Flyer
V-Man's Avatar
Quote:
Originally Posted by iceman88
What radio type do you use? I thought DSM2 was pretty standard?
Futaba (6EX and 8SFG, both are FASST 2.4 GHz systems). Spektrum is common for ARF and RTF models, but I build my own planes.
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Mar 22, 2013, 12:49 PM
Registered User
What are the advantages of the FASST system over DSM2
Mar 22, 2013, 01:54 PM
Airplane and Heli Flyer
V-Man's Avatar
Quote:
Originally Posted by iceman88
What are the advantages of the FASST system over DSM2
It's really a question of opinion, and both camps have their champion. Hit Google and you'll see many, many flamewars about it.

To my knowledge (I might be totally wrong), the differences are as follow. You should really check in the Radios sub-forum for a better answer.

Spektrum
Excellent availability, many RTF and ARF models run on this
Decent price
Voltage cutoff issue (a guy at my field crashed his Hurricane because of this)
No Frequency Hopping

FASST
True Frequency hopping
Said to have better range and response time
Now can use S-Bus technology (true plug and play, plus satellite receiver)
Much more expensive (both Tx and Rx)
Good availability; but to my knowledge, there are no RTF/ARF running on FASST

For a plane like the Twin-Boom Pusher, either system will work perfectly.
Mar 26, 2013, 06:18 PM
Registered User
Final question*s*: For the pushrods, do they need to be straight from the servo to the control horn, at an angle, bent, etc? How do I know they will push and not just bend instead of pushing the control surface.
Mar 26, 2013, 06:26 PM
If I build it, it will fly
Depending on length of rod, guides are your answer. I used coffee stir straws (single straw not the doubled ones).

~psguardian
Last edited by psguardian; Mar 26, 2013 at 06:40 PM.
Mar 26, 2013, 07:34 PM
Registered User
So you hooked the rod to the control horn and servo, and had a coffee straw surround the rod before you hooked it up?
Mar 26, 2013, 07:52 PM
If I build it, it will fly
Right. They sell guide tubes in various sizes, but for most situations a 2-3mm straw works fine. I have seen them glued right to the fuse/boom, which puts a controlled arch into the rod, & raised on a platform of foam or Skewers to keep the rod level. Either works well.

~psguardian
Mar 26, 2013, 08:03 PM
Registered User
Interesting. I'm not sure I will need this, I was more concerned with making sure that the rod will not bend when it should be pushing the control surface the other way. How does having the straw act as a guide prevent the bending?
Mar 26, 2013, 09:01 PM
Airplane and Heli Flyer
V-Man's Avatar
Quote:
Originally Posted by psguardian
Right. They sell guide tubes in various sizes, but for most situations a 2-3mm straw works fine. I have seen them glued right to the fuse/boom, which puts a controlled arch into the rod, & raised on a platform of foam or Skewers to keep the rod level. Either works well.
I used plastic drinking straws from the cafeteria (see the green circles in the image). Worked well.

The guide prevents the pushrod from bending and allows it to do its job of pulling and pushing. Naturally, the guide has to be either rigid or well anchored along its entire length to work.
Mar 27, 2013, 12:38 AM
Registered User
Interesting. I guess I will have to hook them up and see how it goes. How big of a prop did you use? I got the 8040 as suggested and it hits the ground when I have it on the ground..

How do you find the V tail does at control? Is it more difficult or less than a conventional tail setup?
Mar 27, 2013, 11:11 AM
Airplane and Heli Flyer
V-Man's Avatar
Quote:
Originally Posted by iceman88
How big of a prop did you use? I got the 8040 as suggested and it hits the ground when I have it on the ground.
The plane is hand-launched so it doesn't matter. Check the settings of your ESC and make sure the brake setting is OFF, and the prop rotates out of the way on landing. I'm still flying with the original prop after 40-odd landings.

Quote:
How do you find the V tail does at control? Is it more difficult or less than a conventional tail setup?
The same, it just means a different setting in the transmitter.
Mar 27, 2013, 06:03 PM
Registered User
Alright, that is good to know about the prop. I am scared to death that I will land wiht the prop "down" and snap it or the engine parts off. Still waiting for my pushrods, once those are in I'll hook em up and see how it flies..if it does at all.

Is there a way to determine what or "how big" of an ESC is needed? A formula or guide perhaps?

Do you put wheels on your plane? If not, where do you hold it to hand launch, without getting ur fingers cut up by the departing prop?
Mar 27, 2013, 06:32 PM
Airplane and Heli Flyer
V-Man's Avatar
Quote:
Originally Posted by iceman88
Alright, that is good to know about the prop. I am scared to death that I will land wiht the prop "down" and snap it or the engine parts off.
Naw, the path of least resistance is for the prop to rotate out of the way (though you may still lose a prop once and again). Most of my planes are belly-landers and I've only broken props in crashes so far, never landing.

Quote:
Is there a way to determine what or "how big" of an ESC is needed? A formula or guide perhaps?
The ESC needs to be able to take more Amps than the draw of your motor. You can measure this with a Wattmeter, but most of the time the specs of the motor will tell you how many Amps are pulled for a given prop (you may have to dig into reviews or online databases for the more obscure motors).

Quote:
Do you put wheels on your plane?
You could, but on this design it would just add drag, weight and complexity.

Quote:
If not, where do you hold it to hand launch, without getting ur fingers cut up by the departing prop?
My launch method is as follow (this presumes you've checked controls, range check, set timer, etc.):

1) Transmitter in left hand, throttle off, left thumb under throttle stick.
2) Model in right hand, held by the fuselage, below the wing.
3) Turn toward wind.
4) Throw model about 20-30 degrees upward, firmly but smoothly.
5) Wait for model to get about 3-4 feet away. The plane, if well-trimmed and built straight, will begin a shallow climb straight ahead.
6) Push throttle smoothly to max with left thumb.
7) Place right hand on transmitter and begin piloting.
Mar 27, 2013, 06:39 PM
Registered User
Is the ESC rated for continuous or max draw?

That procedure sounds imply enough, I'm still not convinced this thing will ever see the friendly skies...I just have a gut feeling the aerodynamics are going to be all screwed up thanks to my inexperience building..
Mar 27, 2013, 07:28 PM
Airplane and Heli Flyer
V-Man's Avatar
Quote:
Originally Posted by iceman88
Is the ESC rated for continuous or max draw?
I believe it's max draw. Personally, since I use inexpensive equipment, I try to use an ESC about 20-25% larger than the suggested Amps, for safety. So if the specs say 14A with a given prop at max throttle, I use a 18 or 20A ESC.

Quote:
That procedure sounds imply enough, I'm still not convinced this thing will ever see the friendly skies...I just have a gut feeling the aerodynamics are going to be all screwed up thanks to my inexperience building..
Make sure to follow the instructions, get all the measurements accurate, make sure the plane is straight, get the CG right, and it will fly.


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