Oh now thats a very interesting body cut.
Flex wing experimenting
- Thread starter Alan R
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the flexi needs a lot of pull to get it open. the rubber bands weren't really doing it. I need strong rubber, not stretchy rubber.
the music wire I had wasn't cutting it. too light. I picked up an old wiper a while back and tore out the spring, the epoxy is currently drying ...
wiper spring didnt work. 1. it came unglued (ya, ya, string wrap... ) 2. when I bend it in to fit, it stays bent too much 
time for another try at the coil springs. or find some different rubber.
time for another try at the coil springs. or find some different rubber.
wiper spring didnt work. 1. it came unglued (ya, ya, string wrap... ) 2. when I bend it in to fit, it stays bent too much
time for another try at the coil springs. or find some different rubber.
Depending on the size and strength of your flexwing spars, you might try a SMALL diameter "bungee cord", for deployment.
https://www.paracordplanet.com/paracord/shock-elastic-cord/elastic-cord
https://www.amazon.com/Black-Shock-Bungee-Rubber-Rope/dp/B00EYQD56W
https://sgtknots.com/collections/shock-cord/bungee?grid_list=grid-view
https://www.amazon.com/s?k=small+di...888064&tag=googhydr-20&ref=pd_sl_74ii0luxi5_e
Dave F.
oh thank you for suggestion. hadn't thought of that. they have little ones at the $1 store. might check that today.
I had another thought last night: a strip of bicycle tube.
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Have you considered tubular surgical rubber tubing, the type used in spearguns, slingshots, etc.?
https://amzn.to/3f9sqFt
Alan,
Here's a question that I should have asked, right from the start . . .
How big is the rocket being recovered and how big is the Flexwing ?
Dave F.
Here's a question that I should have asked, right from the start . . .
How big is the rocket being recovered and how big is the Flexwing ?
Dave F.
Here's the whole thing, sans NC.
The wing is 24", the BT will eventually get cut down to about 24" also. 38mm tube. Engine is 24mm (D/E).
Total length with booster about 30"
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NOTE : I am NOT a "Flexwing Expert" !
Given the light mass of your rocket ( I was expecting a larger model ), you may encounter issues where the "Gliding Assembly" ( Flexwing above the rocket ) becomes unstable and might become "upset" by a wind gust or other influence. If it does, it may not recover into a glide again. The cause would be the ratio of the weight of the rocket to the weight of the Flexwing ( the rocket being too light or the Flexwing having too much mass ) .
Remember, the mass of the object being recovered in the NASA experiments was MUCH more than the Para-glider ( "flexwing" ) . . . It creates a "pendulum effect" !
What is the weight of the Flexwing ?
What is the weight of the rocket ( with an expended motor onboard ) ?
Dave F.
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TheAviator
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http://www.georgesrockets.com/GRP/CONTEST/Plans-C/FlexWings/Flexwings.htm
See this page for George's thoughts on flexies. I've found the one critical thing for getting a flexie to work consistently is to set the "billow" appropriately. Can't remember what the appropriate amount of billow is, but I think 20-30% more length than taut is what I usually use. I have some notes on my other computer for construction.
See this page for George's thoughts on flexies. I've found the one critical thing for getting a flexie to work consistently is to set the "billow" appropriately. Can't remember what the appropriate amount of billow is, but I think 20-30% more length than taut is what I usually use. I have some notes on my other computer for construction.
I built mine per r/c spec. The material is attached 90deg to the spars, but the spars are limited to 80deg opening (one set of plans). Another set of plans showed a specific length for the cross spar to limit the opening, but didn't give a degree setting.
well.. whoo hoo. I finally got around to finishing this.
It will have its initial launch tomorrow morning.
My biggest worry is that it won't pop all the way out of the tube. the flexi goes all the way down to the motor. I printed a little cup on the bottom of the center spar to catch the ejection charge. some wadding in front of it.
33" long, motor is D12-5. Fin can/body is attached to a bridle on flex wing.
It will have its initial launch tomorrow morning.
My biggest worry is that it won't pop all the way out of the tube. the flexi goes all the way down to the motor. I printed a little cup on the bottom of the center spar to catch the ejection charge. some wadding in front of it.
33" long, motor is D12-5. Fin can/body is attached to a bridle on flex wing.
The limiter "spar". ... not the tape, just the thread. Tape has the spar length marked.
Good luck!
It works.
Launch report
My biggest worry was not a problem. The entirety of the glider was ejected from the body tube.
My sad report: i only got video from pad to apogee... no recovery vid. I guess that means I could say whatever i want and yall would just have to believe me
Broke a fin on landing.
Flexwing ejected and spread. It greatly slowed descent, but it wasn't really 'gliding'. It was dipping, looked nose heavy. need to move cg back.
Today was just a test day. I know it works. Now the effort goes into putting a good trim on the glider. Moving the connection point on the bridal a bit more to the rear should keep it nose up.
There is another scheduled launch in 2 weeks.
on the pad:
Launch report
My biggest worry was not a problem. The entirety of the glider was ejected from the body tube.
My sad report: i only got video from pad to apogee... no recovery vid. I guess that means I could say whatever i want and yall would just have to believe me
Broke a fin on landing.
Flexwing ejected and spread. It greatly slowed descent, but it wasn't really 'gliding'. It was dipping, looked nose heavy. need to move cg back.
Today was just a test day. I know it works. Now the effort goes into putting a good trim on the glider. Moving the connection point on the bridal a bit more to the rear should keep it nose up.
There is another scheduled launch in 2 weeks.
on the pad:
Congratulations on the successful flight .
I was at the Smithsonian Udvar-Hazy Center a couple of years back. They have the Rogallo wing there that they were looking at landing the capsules with. Our tour guide's claim to fame is that he was a hang-glider pilot when he was younger and actually had a crash with another hang-glider one day. Both pilots survived, and the other pilot was Mr Rogallo himself!
.I was at the Smithsonian Udvar-Hazy Center a couple of years back. They have the Rogallo wing there that they were looking at landing the capsules with. Our tour guide's claim to fame is that he was a hang-glider pilot when he was younger and actually had a crash with another hang-glider one day. Both pilots survived, and the other pilot was Mr Rogallo himself!
i went back and looked at the first post on this thread. seems I've been thinking about this working on it for about 9 months. wow. I'm glad i finally got it up in the air. I'm looking forward to the next flight.
Flight report ... YouTube link here. You can watch if you want, but you'll only see it going up.
I had a bad D12, the ejection charge just fizzled. When I examined it, the front cap was still intact. Another guy at the monthly launch had the same problem. G201120 is the code on my motor.
This was actually the 2nd flight. I launched about a month ago at the high school. Unfortunately I messed up the video recording.
First flight worked ok, but the glider was dipping. I was happy that the first flight proved it would push the whole wing out of the tube.
It came down sideways so not much damage except for a split fin, which I fixed with my trusty 15min epoxy, but by the time the next lauch window opened up the winds had picked up and I decided not to go.
Youtube launch vid
I had a bad D12, the ejection charge just fizzled. When I examined it, the front cap was still intact. Another guy at the monthly launch had the same problem. G201120 is the code on my motor.
This was actually the 2nd flight. I launched about a month ago at the high school. Unfortunately I messed up the video recording.
First flight worked ok, but the glider was dipping. I was happy that the first flight proved it would push the whole wing out of the tube.
It came down sideways so not much damage except for a split fin, which I fixed with my trusty 15min epoxy, but by the time the next lauch window opened up the winds had picked up and I decided not to go.
Youtube launch vid
Got it up again today. Good enough flight to prove that it CAN work. Obviously some issues with balance/cg/or something. Wing ejected, entire rocket contained below, but it was having nose-heavy issues, wasn't gliding.
Maybe I'll mess with it in the future to figure that out, but for now it's good enough to know that it can be successful.
Long frustrating project.
Youtube link...
View attachment IMG_0932.mp4
Maybe I'll mess with it in the future to figure that out, but for now it's good enough to know that it can be successful.
Long frustrating project.
Youtube link...
View attachment IMG_0932.mp4
TheAviator
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Looked close! I would suggest having a multi-point harness to hang the tube in a fixed spot, like a line that goes from the tail of the glider to the tail of the rocket, and a line that goes from the nose (inside) of the rocket to the nose of the glider. The body swinging around changes the balance of the glider too much for it to work without that.
That's pretty much what I was thinking when watching it. It was having trouble getting oriented. Very first flight few months ago the wing seemed to "catch" early on. Much better than this flight.
I have all winter to think about it now too. Put the body horizontal like you said, that seems similar to those old NASA pictures above. Or maybe do a 3-point attachment to the wing nose and outer spars.
boomtube-mk2
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And we all know how "great concepts" work out.
In theory, many things are possible.
In reality, many things don't work.
LOL. I stand by my words. Sometimes great concepts require a little greater engineering.
From my perspective, the wild oscillations may be caused by the short length of the attachment lines. Increasing the distance between the Rogallo Wing and the Booster body should slow and reduce the oscillations.
Dave F.
Dave F.
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