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DIY 50mm EDF Grunjet

Grifflyer

WWII fanatic
#1
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
 
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jaredstrees

Well-known member
#13
Afternoon Grifflyer! I’m going to start my build on this tonight. Any tips? The batteries and esc I have are a little big at 1500mah and 60 amp esc, but I’m using gorilla glue to shave a little and I’ll probably shave a little more weight where possible. Looks like a great plane and am looking forward to the build/flight!
 

Grifflyer

WWII fanatic
#14
Afternoon Grifflyer! I’m going to start my build on this tonight. Any tips? The batteries and esc I have are a little big at 1500mah and 60 amp esc, but I’m using gorilla glue to shave a little and I’ll probably shave a little more weight where possible. Looks like a great plane and am looking forward to the build/flight!
Personally....I think you'll be fine, I run on a 1300 and a 40 amp with NO regard to saving weight and it comes in SO slow. So, I think you might not come in as slow, but you'll get a bit more power and make the ground takeoffs even more fun! The only tip I've got is make sure your thrust tube is straight,

And I should probably mention control throws.
Ailerons Low=~15 degrees | High=~24 degrees
Elevator Low=~11 degrees | High=~20 degrees
 
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jaredstrees

Well-known member
#17
Probably not the decals, I'll add some color to it, most likely just a little colored packing tape for orientation. After the maiden and I get a handle on it's flight characteristics I'll most likely build another and really dress her up. Seems like it should be pretty straight forward and quick build. If you get a chance though, could you take a pic of the bottom so I have a 360 view for the build? If not I'm sure I can figure it out.
 

Grifflyer

WWII fanatic
#18
Probably not the decals, I'll add some color to it, most likely just a little colored packing tape for orientation. After the maiden and I get a handle on it's flight characteristics I'll most likely build another and really dress her up. Seems like it should be pretty straight forward and quick build. If you get a chance though, could you take a pic of the bottom so I have a 360 view for the build? If not I'm sure I can figure it out.
sorry I'm a little late but here are some pictures from lots of different angles
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make sure the tail tapers down to one sheet of foam thick.

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