DIY 50mm EDF Grunjet

dap35

Elite member
I like the v tail a bit better because it has rudder control and because I feel that it looks better
I agree the v-tail looks great, but have many compliments on my std tail design from the members at my club. I have not flown the v-tail version, but another plane of mine has some challenges when the throws are high on the v-tail. I built the std version with an added 1.5" rudder and it flies great.
 

2jujube7

Well-known member
I finished up the build this morning, and maidened it in the snow. One problem though: stadium lights. Some ice gathered up on my LE from all the landings I was doing to trim it out (I'm not good enough of a flyer yet to trim it out in the air), so I'm blaming the "hug with the lightpost" on the icing and the funky flying characteristics it gave the airfoil. Luckily it's not very broken because the crash was right after I took off and I didn't have much airspeed yet. Just need to remake the nose and glue the tail back on.

Additionally, I thought that the roll rate was pretty excessive (that's an understatement :ROFLMAO:) and I think I'll reduce the ailerons sizes next time I build one. Other than that, it was a great flyer and started to zoom about pretty fast whenever forgot that I was trying to fly it slow and not crash. :D It's a great plane, and I'd recommend it to anyone. I'm looking to repairing it and flying again tomorrow :)

Oh, and the setup. I saw in this thread that many of you were flying 4s and had a pretty heavy AUW. I tried to keep it light, as I only have Valuehobby's 50mm 3s EDF (Which supposedly makes 770g thrust). Also have a 3s 1300mAh battery, which seems to work great. AUW is exactly 420 grams, which puts the thrust/weight at around 1.75:1

Here's a picture of it before the maiden. Cheers!
Grunjet.jpg
 

Grifflyer

WWII fanatic
I finished up the build this morning, and maidened it in the snow. One problem though: stadium lights. Some ice gathered up on my LE from all the landings I was doing to trim it out (I'm not good enough of a flyer yet to trim it out in the air), so I'm blaming the "hug with the lightpost" on the icing and the funky flying characteristics it gave the airfoil. Luckily it's not very broken because the crash was right after I took off and I didn't have much airspeed yet. Just need to remake the nose and glue the tail back on.

Additionally, I thought that the roll rate was pretty excessive (that's an understatement :ROFLMAO:) and I think I'll reduce the ailerons sizes next time I build one. Other than that, it was a great flyer and started to zoom about pretty fast whenever forgot that I was trying to fly it slow and not crash. :D It's a great plane, and I'd recommend it to anyone. I'm looking to repairing it and flying again tomorrow :)

Oh, and the setup. I saw in this thread that many of you were flying 4s and had a pretty heavy AUW. I tried to keep it light, as I only have Valuehobby's 50mm 3s EDF (Which supposedly makes 770g thrust). Also have a 3s 1300mAh battery, which seems to work great. AUW is exactly 420 grams, which puts the thrust/weight at around 1.75:1

Here's a picture of it before the maiden. Cheers!
View attachment 187158
Hahaha hug the lightpost that’s hilarious. I’m glad it flew will for you!!
 

Winglet

Well-known member
Great story Jube7. I pictured the whole thing in my mind.:eek: The ailerons are very sensitive. No need to make them smaller, just set them up with less throw. If you have expo control on your transmitter, set it up to about +50 percent and it will tame it down a lot! I was out flying my RedSled Vtail Grunjet today in unexpected really nice weather. 34F but zero wind and sunny. 7 great flights on mine today. Best part is sliding off and on to our grass runway. Taxis great too! My third one is well on the way to completion. Photos to follow.
 

Winglet

Well-known member
My last time to our field this year. Wrapped up 2020 flying my Redsled Grunjet and my Arrows Hobby Viper Jet. Both are 50mm EDFs and are both great airplanes. The major difference is I didn't get to build the Viper. Basically just opened the box and glued the wing on. I really enjoy constructing the Grunjet and I like the way it taxis, takes off and lands all on it's belly. Here is a picture of my 3rd Grunjet build in progress. My first 2 are V tail. Will see how the rudder works on the yellow one!
gjand viper.jpg
yellowgrun.jpg
 

Grifflyer

WWII fanatic
My last time to our field this year. Wrapped up 2020 flying my Redsled Grunjet and my Arrows Hobby Viper Jet. Both are 50mm EDFs and are both great airplanes. The major difference is I didn't get to build the Viper. Basically just opened the box and glued the wing on. I really enjoy constructing the Grunjet and I like the way it taxis, takes off and lands all on it's belly. Here is a picture of my 3rd Grunjet build in progress. My first 2 are V tail. Will see how the rudder works on the yellow one!
View attachment 187343 View attachment 187345
That’s definitely going to be the most beautiful Grunjet to date!! I might have to steal some of your ideas the next time I paint a Grunjet. It’s so awesome to hear that you’re enjoying it. That viper jet is sweet!
 

Grifflyer

WWII fanatic
Hey Grifflyer,
For my next Grunjet I'm thinking Amphibian? I think the design would lend it self well to water flying with only a couple of little pontoons attached to the wings? What do you think?
I’ve actually thought about that before haha. Pontoons would definitely be the best way to go, you wouldn’t need to make any changes to the fuselage that way.
 

2jujube7

Well-known member
I was out flying my RedSled Vtail Grunjet today in unexpected really nice weather. 34F but zero wind and sunny. 7 great flights on mine today.

Wow, I think I must have gotten your weather today!!! (In Ohio) The temp is 31F, there's zero wind, and it's very sunny. :ROFLMAO: Yesterday was heckin windy too, so I'm going to be flying quite a bit today! I already had 3 flights on my grunjet, and 1 on my MS Mustang.
 

Winglet

Well-known member
My third GJ build has taken flight. We had an unexpected warmish, no wind day so got the maiden in plus another 8 packs. Flew great and was the focus of a sizeable group of pilots at our club. Everyone loved it! I think at least 2 more are under construction?

Our take on the straight tail vs the V.

Most noteably there is a very different sound. (straight tail much more pleasing)

Better overall performance with the V tail. Slightly better climb and top speed. My suggestion.....build them both!!

gj fleet.jpg