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FPV Scratch build plane?

#1
Hi,

I want to build to make a long range fpv plane which I can belly land in the grass. I have an 1800 KV engine (stock bixler engine) also I have a 30 amps esc. I can choose between an 5X5 prop or n 6X4 prop, I would like the 6x4 more because the 5X5 is pretty flimsy. I hope that people have some ideas/want to help me. I am using the readymaderc 300mw 1.2 GHz VTX and EZuhf with two antenna's. (Diversity) I am using a 1.2 GHz receiver with upgraded saw filter. Also I am using an 8dbi patch optimizd for 1280 MHz. I am planning to build a vee antenna and a biquad.

Greetings Arman, nonamerc

I have flown the sky eagle by nine eagles and I have the bixler since january and I am learning fpv now. (I have flown FPV for about 5-6 hours, this number is increasing daily)
 

earthsciteach

Moderator
Moderator
#5
What's wrong with the Bixler for this?

If you are in the mood to build an airframe for this purpose, a flying wing is very easy to construct; flies efficiently and makes a good fpv platform.
 
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#6
What's wrong with the Bixler for this?

If you are in the mood to build an airframe for this purpose, a flying wing is very easy to construct; flies efficiently and makes a good fpv platform.
Yea I like the idea of a wing, but does an 1800Kv engine has enough power to carry the plane and my FPV electronics?

Arman
 

earthsciteach

Moderator
Moderator
#7
My Assassin flies on a 2200kv, 1.8 ounce motor with a 30 amp esc and 1800 mah, 11.1 v battery. That produces 32 ounces of thrust at 28 amps. It will fly right out of my hand without tossing, so I have no doubt it would carry fpv gear. Your 1800 kv, matched with the right prop should as well, depending on the weight of the motor.
 
#8
My Assassin flies on a 2200kv, 1.8 ounce motor with a 30 amp esc and 1800 mah, 11.1 v battery. That produces 32 ounces of thrust at 28 amps. It will fly right out of my hand without tossing, so I have no doubt it would carry fpv gear. Your 1800 kv, matched with the right prop should as well, depending on the weight of the motor.
I have an 6x4E prop, will this work? Do you have any build plans/pictures of your wing? I think that I am going to use an 2200 mah but I can also use an 1500 mah but I think that I want a wing that can carry an 2200 mah and maybe two 2200 mah batteries
 

earthsciteach

Moderator
Moderator
#9
I don't have plans of the Assassin, as it is a purchased wing. Check out www.crashtesthobbies.com for info. They also have other models which would be much more suited to carrying fpv equipment. The Assassin is far from ideal for this.

With an 1800 KV motor you may be able to go to a slightly bigger prop than a 6", but be careful. For fpv, I would want more torque, not so much top end speed. As such, I don't think 1800 kv is ideal. Something around 1100 kv with an 8x4 or 8x6 prop would be more suitable, in my opinion.

I am scratchbuilding an fpv wing for a couple of friends right now. You can check out my build log here: http://forum.flitetest.com/showthread.php?2368-fpv-flying-wing-build-log

I have no idea what motor/prop/esc I am using at this point as I am fiberglassing the whole thing and don't know the all up weight, yet.

What materials are you planning on using?
 
#10
Well I am going to use some foam I think but in the netherlands we dont have a such thing as dollar tree foam. Quite anoying because you will need to buy special foam etc etc.

Nice build log looks like a X8 from bevrc. Do you know any scratchbuilds for 1800 kv engines with an 6x4 prop?
 
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earthsciteach

Moderator
Moderator
#12
It would be extremely helpful to you if you knew the thrust that the 1800 kv motor and prop combo produces. Once you know the materials you are going to build with, you can determine the amount of that material you can use to end up with a decent thrust-to-weight ratio taking into account the weight of all other components.

Quick tip for flying wings - The more sweep you have (to a point) the more forgiving the cg location will be. This is a nice cg calculator that is very helpful when laying out the wing: http://fwcg.3dzone.dk/ Let me know if you have any questions about the calculator.
 
#13
It would be extremely helpful to you if you knew the thrust that the 1800 kv motor and prop combo produces. Once you know the materials you are going to build with, you can determine the amount of that material you can use to end up with a decent thrust-to-weight ratio taking into account the weight of all other components.

Quick tip for flying wings - The more sweep you have (to a point) the more forgiving the cg location will be. This is a nice cg calculator that is very helpful when laying out the wing: http://fwcg.3dzone.dk/ Let me know if you have any questions about the calculator.
I have searched everywhere for the thrust that the stock engine gives but I cant find it no where :( I saw the calculator, I understand all things except for the ''sweep' is that the point from the cg to the nose??
 

earthsciteach

Moderator
Moderator
#14
No, the sweep is the angle that the wings rake backwards.

I looked earlier for numbers on the stock Bixler motor without much success. I think it will get the job done for you, though.