DIY 50mm EDF Grunjet

[Grifflyer]

How much for 64mm

There have been people who run it at regular size with a 64mm edf and have had great results! You’ll have to scale up the thrust tube will have to be cut a little bit bigger but everything else will work at the normal size.

 

[2jujube7]

What % do I expand the plans for 64mm

64/50=1.28

128%, but as Grifflyer said, the normal sized plans should work great.

 

[Lester]

64/50=1.28

128%, but as Grifflyer said, the normal sized plans should work great.

Thank u all !!! I'll stick with standard size ! Standard is 20×30 ???

 

[dap35]

Thank u all !!! I'll stick with standard size ! Standard is 20×30 ???

I built mine with a 64mm and only changed the thrust tube and mount to fit the EDF.

 

[The Hangar]

Here’s my maiden of the grunjet. Apart from a sketchy launch due to it being quite far out of trim, it went really well! I love this plane - I put 5 packs through it that day. The maiden was on a 1500 4s which is a perfect size, but I only have one of those so I ran it several times on a 2200 3s which also worked very well but was a bit slower. I’m planning on trying it out on a 2200 4s, so I’ll give an update once that happens. If you haven’t built one of these yet, do it! It’s so worth it!

 

[The Fopster]

Here’s my maiden of the grunjet. Apart from a sketchy launch due to it being quite far out of trim, it went really well! I love this plane - I put 5 packs through it that day. The maiden was on a 1500 4s which is a perfect size, but I only have one of those so I ran it several times on a 2200 3s which also worked very well but was a bit slower. I’m planning on trying it out on a 2200 4s, so I’ll give an update once that happens. If you haven’t built one of these yet, do it! It’s so worth it!

Nice catch at the end. Ninja skills!

 

[Lester]

Thank u all !!! I'll stick with standard size ! Standard is 20×30 ???

Nice catch at the end. Ninja skills!

Going to start tomorrow evening .64 on 4s 😉thanks for the kick in the right direction!!!!!😎

 

[Homey]

This comes to the field with me almost every time. Does everything you ask it to!
Flew this battery to the ground! Lol

Peter

 

[Racer649]

Introducing the Grunjet, a two sheet foamboard performance jet flying fast and sporty, slows down to a crawl on landings, and is packed with amazing vertical performance, all only costing $80 to build! With this plane you have the option of building the plane with a V tail or a standard tail, there are no real handling differences between the two other than the fact that the V atil has a rudder.

-Videos

-Overview

-Speed
While certainly not a speed demon, coming out of a dive it might get up to roughly 70mph.

-Handling
With such a low wing loading this thing flies like a trainer, and with such large control surfaces you're able to pull of a ton of aerobatic maneuvers.

-Stalls
They can become little rough but I have yet to drop a wing

-Aerobatics
If you build the plane with a standard tail you'll only be able to do the basic such as: loops, rolls, inverted, split S's etc. Even if you decide to build the V tail there's quite a bit of adverse roll when you apply rudder (a common characteristic of V tails) so you'll still be relatively limited to the basics

-Take offs
You can either do an underhand launch while holding the thrust tube, or my favorite, just plop it on the grass and give it full throttle and off she goes!

-Landings
With such a large wing and low wing loading you can glide it in without any problem, but I prefer to leave a little bit of throttle on to get some airflow over the elevator so I can flare it right before hitting the ground.

-Skill level
This is the easiest jet I've ever flown, if you want to dip your feet into the sweet waters of EDF jets this with by far the best way to do that. This would make a great second or third bank and yank airplane.



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-Plans
Grunjet Plans V2.0

Any build instructions or video?

 

[2jujube7]

Any build instructions or video?

It's pretty simple, everything should be self explanatory if you've built any FT models. Ask if you have any questions.

 

[Racer649]

I just built one. Where should the balance point be? Thanks

 

[dap35]

I just built one. Where should the balance point be? Thanks

I measure 7.46" in front of the trailing edge of the wing. The CG location is shown by this symbol on the plans.

 

[Racer649]

I measure 7.46" in front of the trailing edge of the wing. The CG location is shown by this symbol on the plans.

View attachment 229047

Thank you

 

[Taildragger]

Almost six years later this design is still rocking! Probably one of the most fun per dollar planes I have

 

[FlyerInStyle]

Almost six years later this design is still rocking! Probably one of the most fun per dollar planes I have

could it fly on a 3s edf that produces almost no power?

 

[Taildragger]

could it fly on a 3s edf that produces almost no power?

The “patriotic” plane in the video is powered by a powerfun 3s 50mm, so I think the answer would be yes.

 

[FlyerInStyle]

The “patriotic” plane in the video is powered by a powerfun 3s 50mm, so I think the answer would be yes.

ok, how much power does it need to take off, and what motor is in your edf? mine has a tiny motor on 4 blades...

 

[Taildragger]

ok, how much power does it need to take off, and what motor is in your edf? mine has a tiny motor on 4 blades...

I think mine is like a 4900kv 2212, not sure 100%
It also has 11 blades. I'm not sure about yours, but I got mine cheap from here:

Powerfun 50mm 11 Blade 4900KV 3S EDF Fan Motor Combo-BFM-MT-

valuehobby.com

 

[FlyerInStyle]

I think mine is like a 4900kv 2212, not sure 100%
It also has 11 blades. I'm not sure about yours, but I got mine cheap from here:

Powerfun 50mm 11 Blade 4900KV 3S EDF Fan Motor Combo-BFM-MT-

valuehobby.com

ok, thanks, I might try, I jsut want to find something that I CAN put that severely underpowered 3s edf into, this plane is on my list, but want to verify that it works before I start building. How much thrust does your edf produce at crusing power?