2025 Speed Challenge - Telnar1236

telnar1236

Elite member
Hmmm: Mr Man or telnar1236. Interesting contest: elegant advanced theory versus brute force engineering. Getting out popcorn and beer.

Oh and you dont get airspeed increase after high point. Was just checking the audience level.
I strongly suspect Mr Man is going to come out on top here, but we'll see what happens - I spent far too long yesterday trying to characterize the EDF pitch speed and thrust curve with hand calcs, but the end result is that my current estimate is about 140 mph.
 

Houndpup Rc

Legendary member
Hmmm: Mr Man or telnar1236. Interesting contest: elegant advanced theory versus brute force engineering. Getting out popcorn and beer.

Oh and you dont get airspeed increase after high point. Was just checking the audience level.
What about old pup in the corner here 😂😂 ...I hit 158...Just uploading it to YT right now!
 

Houndpup Rc

Legendary member
I strongly suspect Mr Man is going to come out on top here, but we'll see what happens - I spent far too long yesterday trying to characterize the EDF pitch speed and thrust curve with hand calcs, but the end result is that my current estimate is about 140 mph.
I am going to give him a run for his money...I am only 4mph beneath him...For now....
 

telnar1236

Elite member
Well... it's done... so I guess I don't get to escape having to try and fly this thing.
1000003183.jpg

The final AUW is 523 g without the GPS module and 560 g with it installed. I forgot to account for it in the weight calculations or in terms of finding space, but thankfully it fits neatly in the nose and the plane still balances out with it installed although it's a bit heavier than I was thinking yesterday. It's a bit hard to describe just how much of a brick this thing feels like, but it should have enough thrust to power through it.
1000003182.jpg
 

Houndpup Rc

Legendary member
Well... it's done... so I guess I don't get to escape having to try and fly this thing.
View attachment 252755
The final AUW is 523 g without the GPS module and 560 g with it installed. I forgot to account for it in the weight calculations or in terms of finding space, but thankfully it fits neatly in the nose and the plane still balances out with it installed although it's a bit heavier than I was thinking yesterday. It's a bit hard to describe just how much of a brick this thing feels like, but it should have enough thrust to power through it.
View attachment 252756
Looks great!!!
 

Houndpup Rc

Legendary member
Well... it's done... so I guess I don't get to escape having to try and fly this thing.
View attachment 252755
The final AUW is 523 g without the GPS module and 560 g with it installed. I forgot to account for it in the weight calculations or in terms of finding space, but thankfully it fits neatly in the nose and the plane still balances out with it installed although it's a bit heavier than I was thinking yesterday. It's a bit hard to describe just how much of a brick this thing feels like, but it should have enough thrust to power through it.
View attachment 252756
I think the weight will be fine because my radjet is slightly heavier and it has a 28" wing span so it might be a little harder to launch and land but it should fly....
 

telnar1236

Elite member
I think the weight will be fine because my radjet is slightly heavier and it has a 28" wing span so it might be a little harder to launch and land but it should fly....
Good to know - that's what all my calculations say too, but it's still hard to imagine. Looks like you should have about twice the wing area so my stall speed should be about 40% higher which is a bit worrying.
But it is EDF so getting up speed will be a little harder....
Not sure normal EDF considerations for thrust apply with this one. TWR is about 1.6 so I should be able to build up speed quite quickly - about 30 mph every second.
 

Houndpup Rc

Legendary member
Good to know - that's what all my calculations say too, but it's still hard to imagine. Looks like you should have about twice the wing area so my stall speed should be about 40% higher which is a bit worrying.
True, though it looks like yours might be a little better balanced...
 

telnar1236

Elite member
I was going to try and fly my jet Wednesday. I've been using a little 3D printed test part to see if it gets too hot for PLA in my car since May and it had had zero issues with warping up until this week, so I felt pretty good about leaving the plane in my car while I was at work. But unfortunately, when I got out and looked in my trunk, everything had picked that day to get too hot and deform. The picture doesn't look too bad till you look at the trailing edge to see how much it curves now. You can also see how the hatch no longer fits properly. I did my best to bend it back into shape while it was still somewhat flexible, but the wings were too warped, and it was unflyable.
1755382023751.png

The good news is it prints so quickly that I had time to fully rebuild it again. Unfortunately, this means I'm going to get one chance to try and fly it in time, and that chance will need to be tomorrow. To make sure it launches well, I'm also putting together a bungee launcher, but at this point I'm about 50/50 on if I'll get it flying in time. If not, I'll still try and put it in the air sometime next week and it just won't count for the competition sadly.
1755382505998.png