Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
A Micro R/C boost glider
#1
I've built a couple R/C rocket gliders over the years, both fixed wing and the Switchblade XP swing wing I was selling for a while, but decided a boost glider was in order. I've seen a couple videos of the Northhawk flying but honestly wasn't impressed by its launch pattern. It suffers from all the problems of my Switchblade XP--underpowered, and weathercocks like crazy. Like the XP, it glides very nicely. The use of the UMX bricks for control has really advanced small gliders.

Well I have a preliminary design I've been working on. The first iteration is a diminuitive 12" span, based off my Carbonette 12 kits. Before I even launched it, test throws revealed that it had potential as a discus launch model similar to the Whipit, only better. But the wing needed to be bigger. We launched it anyway. Height on a B6-4 was unbelievable. An average R/C pilot would have orientation problems it was so high. It's too sensitive to turbulence though, and having so little wing area, wing penetration is an issue. It's awesome on calm days, but if there's wind, you need something that doesn't work at stupid low reynolds numbers.
Image

The next version has been built and is a 19" span with the same fuselage and a top fin added for discus launches. It'll need an offset pod to keep from burning said fin off. 

Image

Image

Still needs some work. The battery is too far forward for the short connector cables on the UMX bricks. I'm going to widen the fuselage core to 1/4" (currently 1/8"), run the wire through the fuselage, and have the battery opening on top instead of the bottom. Also, the plywood cladding will run all the way to the nose. This will actually make it significantly stronger than the UMX whipit without adding more than a gram of weight. Since the model is too light anyway, this can only help.

It flies great, by the way. Hopefully I'll have a launch video available on Monday.
Reply
#2
(01-11-2018, 12:44 PM)Josh Finn Wrote: I've built a couple R/C rocket gliders over the years, both fixed wing and the Switchblade XP swing wing I was selling for a while, but decided a boost glider was in order. I've seen a couple videos of the Northhawk flying but honestly wasn't impressed by its launch pattern. It suffers from all the problems of my Switchblade XP--underpowered, and weathercocks like crazy. Like the XP, it glides very nicely. The use of the UMX bricks for control has really advanced small gliders.

Well I have a preliminary design I've been working on. The first iteration is a diminuitive 12" span, based off my Carbonette 12 kits. Before I even launched it, test throws revealed that it had potential as a discus launch model similar to the Whipit, only better. But the wing needed to be bigger. We launched it anyway. Height on a B6-4 was unbelievable. An average R/C pilot would have orientation problems it was so high. It's too sensitive to turbulence though, and having so little wing area, wing penetration is an issue. It's awesome on calm days, but if there's wind, you need something that doesn't work at stupid low reynolds numbers.
Image

The next version has been built and is a 19" span with the same fuselage and a top fin added for discus launches. It'll need an offset pod to keep from burning said fin off. 

Image

Image

Still needs some work. The battery is too far forward for the short connector cables on the UMX bricks. I'm going to widen the fuselage core to 1/4" (currently 1/8"), run the wire through the fuselage, and have the battery opening on top instead of the bottom. Also, the plywood cladding will run all the way to the nose. This will actually make it significantly stronger than the UMX whipit without adding more than a gram of weight. Since the model is too light anyway, this can only help.

It flies great, by the way. Hopefully I'll have a launch video available on Monday.

very interesting
Reply
#3
This is interesting. I was active in electric powered RC from about 1980 (when it was really hard) until the rocketry bug bit me again (about 9 years ago). I have some UMX equipment (and a Dx7) and have been looking to finally combine the RC with the rockets. I have a North Hawk kit on the shelf but this sounds really intriguing.

That said, any way we can see the images or do I have to go join the flitetest forum to see ‘em?
Bernard Cawley
NAR 89020
AMA 42160
“BEC” on YORF, TRF, RCGroups and a few other places
Reply
#4
(01-16-2018, 08:40 PM)Bernard Cawley Wrote: That said, any way we can see the images or do I have to go join the flitetest forum to see ‘em?

Nope. This forum won't let me directly upload pictures. It's a pain in the neck.
Reply
#5
Hopefully Josh can post some data on his web site: http://jhaerospace.com/
Reply
#6
One other thought....UMX battery extensions are available from HobbyKing (and I’m sure elsewhere) so it would be pretty straightforward to make that lead an inch or so longer by cutting off the male plug and installing the extension in place of the stock battery lead. (Or at least that’s what I get by looking at the UMX bits I have readily to hand).

So if another inch gets the power cell and the brick in the right spots, I wouldn’t see that as a problem.
Bernard Cawley
NAR 89020
AMA 42160
“BEC” on YORF, TRF, RCGroups and a few other places
Reply
#7
I now have something better than photos. Try this on for size:




That's over 100 seconds, on a B engine, with a bunch of aerobatics and shenanigans. Yes, it will take C's. I haven't gotten any good videos of that so far but I'll keep trying.
Reply
#8
Impressive. That little Aleda boost glider also looks like a winner. Sending money your way shortly.
Bernard Cawley
NAR 89020
AMA 42160
“BEC” on YORF, TRF, RCGroups and a few other places
Reply
#9
(01-31-2018, 01:31 AM)Bernard Cawley Wrote: Impressive. That little Aleda boost glider also looks like a winner. Sending money your way shortly.

Bernard, let me know how to builds go!
Reply
#10
Will do. I expect I’ll be building one of the Aleda-R models tomorrow.
Bernard Cawley
NAR 89020
AMA 42160
“BEC” on YORF, TRF, RCGroups and a few other places
Reply


Forum Jump:


Users browsing this thread: 1 Guest(s)