rocket launched rogallo glider

I am currently building a rocket launched rogallo wing glider which you can view at:
https://home.iprimus.com.au/phillipeagles/rocketglider_index.html
The glider has built in rc 2 servos and glides reasonably well. Parachute deployment from rear of rocket (at margin between black and orange sections.)-untested. Wingspan about 1 meter, weight 650gm booster 700gms. Deployment by perfectflite altimeter. Need to incorporate a backup in there. via timer or rc?
Will do some test flights with E F engines without glider. G engine would take booster and glider to about 250mr.
Has anyone else tried this?
Any constructive suggestions?

Phil

Cool, VERY unique idea. It looks like it should work. 650g and 700g each? so 1350 together?

Phil,

Very neat project. I especially like the V-tail. I've not seen anyone do such a large Rogallo, especially not RC.

But much smaller, free flight, flex-wing gliders are fairly easy to build and big fun. NAR has a whole competition class just for them (they had to take them out of the boost glider class because they tend to thermal way better than standard boost gliders). In general, flexies are fairly easy to build but a real bear to trim. Lots of fun, though.

Great explanation of flexies, with plans, can be read at:

https://www.astre471.org/Newsletter/sd1998-0102.pdf

Great article on trimming flexies:

https://www.glasseyeproductions.org/rockets/fwrd/fwrd.pdf

Of note for your project, Phil, is that a large component of how well Rogallo's (flexies) fly has to do with the relative stiffness (tightness) of the front part of the wing as compared to the looser rear part. Flexies seem to work best when the front part of the wing is stretched tight and the rear portion is looser (not stretched tight but not so loose as to be flapping either). The art is learning how to fashion the wings so as to optimize both portions.

Only hard part of building small flexies is making the spring, but if you want to avoid that you can buy a flexie kit from QCR (Qualified Competition Rockets) https://www.qcrhobbies.com/gliders.html. QCR flexies are also carried by Heavenly Hobbies (https://store.heavenlyhobbies.com/07-033-0130.html).

Thanks again for posting such a cool project. Really interested in flight reports.

Steve

[POW]Eagle159;251786 said:

Cool, VERY unique idea. It looks like it should work. 650g and 700g each? so 1350 together?

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I would prefer it to be lighter but....it all adds up.

Gus said:

Phil,

Very neat project. I especially like the V-tail. I've not seen anyone do such a large Rogallo, especially not RC.

Thanks again for posting such a cool project. Really interested in flight reports.

Steve

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Thanks for the information links Steve. The leading edge of the wing is carbon fibre tube and it is unfolded by a carbon fibre strut pulled by an old fashioned elastic band.
I stretched some elastic cord through the back end of the wing fabric to tighten it and reduce the amount of "flapping".
The V tail folds back and together to slide inside the booster fuselage.
The big question is whether the glider will deploy vertically from under a parachute at apogee....a difficult thing to test.

Phil

That's a neat idea, so under chute the glider is supposed to slip out of the tube and then pop open?

Frank

burkefj said:

That's a neat idea, so under chute the glider is supposed to slip out of the tube and then pop open?

Frank

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That is what is supposed to happen. At the moment I have a perfectflite altimeter to trigger the parachute ejection at apogee. What would you suggest as a backup to that? :eyeroll:
Would a timer be the best alternative with a second ejection charge or could the backup be wired into the same charge? If the first one works then it would be preferable for a second one not to be ignited.

I have added a radio control backup to the perfectflite altimeter chute deployment. By deflecting the glider's elevator down(while it is folded inside the rocket fuselage), a switch is moved to "on" position to power a backup ematch to the ejection charge. I have added a power switch for the gliders electronics behind the nose cone so it can be switched on just before launch. Also i have replaced the balsa v-tail with a light plywood. While it is heavier, the extra strength will probably be beneficial if the deployment should be less than gentle. :fly:

philip said:

I have added a radio control backup to the perfectflite altimeter chute deployment. By deflecting the glider's elevator down(while it is folded inside the rocket fuselage), a switch is moved to "on" position to power a backup ematch to the ejection charge. I have added a power switch for the gliders electronics behind the nose cone so it can be switched on just before launch. Also i have replaced the balsa v-tail with a light plywood. While it is heavier, the extra strength will probably be beneficial if the deployment should be less than gentle. :fly:

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Cool. How does the V-tail fit into the rocket?

The v-tail can be pulled together and turned back to slide into the tube.

Glider wingspan is 82cm - 32 inches. Wing loading 2800gm/sqr mr or 9.2 ounces / sqr ft. Which is an approximation to the wing loading of a sail plane

:fly:

I am trying to calculate the black powder ejection charge for the rocket.
diameter 2.6 inches, length of parachute compartment 6 inches,
assuming 15psi c=.006

cddl=.006x2.6x2.6x6=.24 gm
over roughly 5sqr inches that is 75lb pressure which seems a lot.
Does .24gm of black powder roughly equate to .24 cubic centimetres?

The parachute i have is 55cm (21inch) in diameter. The booster part of the glider is 700gm which would mean a descent rate of 7.7mr p/s or 25 ft/s. I suspect this is too fast?
I think i would need an 80cm chute for a 5mps - 17ftps descent which seems more reasonable???

17fps is a nice decent rate, I'd target that if you have the recovery area and body tube room. However your fins don't extend below the tube so you can probably get by with a higher decent rate and not damage anything.

Frank

philip said:

The parachute i have is 55cm (21inch) in diameter. The booster part of the glider is 700gm which would mean a descent rate of 7.7mr p/s or 25 ft/s. I suspect this is too fast?
I think i would need an 80cm chute for a 5mps - 17ftps descent which seems more reasonable???

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I am thinking of getting a CF30 crossfire parachute from top flight recovery.
https://topflightrecoveryllc.homestead.com/page1.html

They look well made but no spill hole. Any suggestions regarding that or other suppliers?

philip said:

I am thinking of getting a CF30 crossfire parachute from top flight recovery.
https://topflightrecoveryllc.homestead.com/page1.html

They look well made but no spill hole. Any suggestions regarding that or other suppliers?

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No idea about suitability for your purpose, but Top Flight chutes are top quality, and the supplier himself is as good as they get.

Man i hope this works and I would love to infklight pictures or viseo
Cheers
Fred

I had been hoping to use the RC of the glider to flick a switch and fire up an ematch as a back up to the the hialt45k altimeter drogue deploy. But having done some testing i realise that the onboard batteries - a 9v for the altimeter and 4.8v 600mah battery for the glider don't have the power to do that and as the overall weight is already up around 1.5kg, a heavier battery wouldnt be desirable. I guess some sort of capacitor would have to be linked into the circuit to hold enough charge for that purpose but this is the extent of my electronics knowledge. Or I could just wire the main chute deployment into the same ejection charge and set it as close as possible to the expected altitude?? Any suggestions?

I have bought a TFR crossfire parachute for my 2lb booster. It is 30 inches across when laid flat and is supposed to be suitable for weights up to 3.5lb. It is well constructed but to me it looks too small for the task of a 20fps descent. Comments anyone?
Nevertheless, possibly attempting a launch of the glider this weekend if the wet and windy weather holds off for a few days.

Should be fine. The shape of the inflated chute really gives it more drag than you'd think.

Looking forward to flight reports and photos!

kj

philip said:

I had been hoping to use the RC of the glider to flick a switch and fire up an ematch as a back up to the the hialt45k altimeter drogue deploy. But having done some testing i realise that the onboard batteries - a 9v for the altimeter and 4.8v 600mah battery for the glider don't have the power to do that and as the overall weight is already up around 1.5kg, a heavier battery wouldnt be desirable. I guess some sort of capacitor would have to be linked into the circuit to hold enough charge for that purpose but this is the extent of my electronics knowledge. Or I could just wire the main chute deployment into the same ejection charge and set it as close as possible to the expected altitude?? Any suggestions?

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This doesn't sound quite right. Either of those batteries should be able to fire any ematch. Perhaps the problem is that you're missing some electronics to convert the servo pwm signal to a switch? You can use a DC brush motor ESC, or buy a part that is designed to turn power on and off from a servo signal.

Adrian A said:

This doesn't sound quite right. Either of those batteries should be able to fire any ematch. Perhaps the problem is that you're missing some electronics to convert the servo pwm signal to a switch? You can use a DC brush motor ESC, or buy a part that is designed to turn power on and off from a servo signal.

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I actually worked out the problem was simply a flat battery! But I am going to launch just using the drogue and main deployment from the altimeter without any RC assistance.

We had a successful first flight of the glider today. The glider plus booster weighed around 1500gm. With a G80 aerotech it got up to 616ft according to the altimeter. The booster flew straight and the perfectflite altimeter ejected the parachute just after apogee. The CF30 crossfire parachute deployed perfectly and the glider slid out of the booster without any problems. The glider dropped for some distance before the wing unfolded properly and it started a fast steep glide. I gave it as much up trim and elevator as possible with the RC but it seemed nose heavy though controllable and landed without any damage. It took over an hour to prepare for launch so some simplification is required to reduce the potential for failures. On recovery the altimeter had switched off - due to a loose fitting wire! I will try to have the video up on Youtube by tomorrow.

Yes please! Video or pictures. I am interested in your build.

Here is the video of the glider. Unfortunately the flight is over pretty quickly, but the glider and booster both came down intact. I should have applied some left rudder to pull the glider out of the spiral and prolong the flight. The question is how to improve the design and get more altitude? It was launched with a G80-4t (cost around $60)and got to 616ft so that is a lot of money for a short flight. Obviously I need to look at trimming down the weight and streamlining the deign but an RC rogallo glider is always going to be a reasonably heavy payload. [video=youtube;B_B3rSx0-bQ]https://www.youtube.com/watch?v=B_B3rSx0-bQ&feature=youtu.be[/video]

Definitely a good first flight. I agree the glider looked a little nose heavy in flight. I like the idea of using the nose cone like you did, but I bet that's where all the extra mass up front is. I like that you tried to compensate by having the servos in the rear. Maybe you can make the glider without the nose cone and move the gear up front to change the mass distribution? This is a great project!

kj

There are more experienced R/C modelers here than me, but I tend to think that gliders from rockets may need to pick up some downward speed and then require some up-elevon (if you have it) to go into glide mode.

kjohnson said:

Definitely a good first flight. I agree the glider looked a little nose heavy in flight. I like the idea of using the nose cone like you did, but I bet that's where all the extra mass up front is. I like that you tried to compensate by having the servos in the rear. Maybe you can make the glider without the nose cone and move the gear up front to change the mass distribution? This is a great project!

kj

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If I had trimmed it to the left to stop the steep spiral it would have flown a lot longer but I didnt realise that until after viewing the video. I applied full up elevator but it turned out the left elevator (of the v-tail) had more up deflection which probably caused the spiralling. Considering the low wing loading it should have hung a lot longer in the air and not beaten the booster to the ground. But I guess all the mechanisms worked as they were supposed too and I can develop it further. The main factor would be weight reduction.

The glider is ready for another flight. The main obstacle at the moment is the windy weather which rarely stops this time of year and a new housing estate is beginning to creep across the launch area. I have removed excess weight from the glider to bring it down to about 600gm and the booster is about 900. I have changed the internal altimeter switch to an external plug and made a few other minor changes. Tested the glider on a steep slope and it settled into a slow gentle glide with the v-tail pitch adjusted to the correct angle,battery and receiver shifted as far forward as possible and no elevator input. If the wing unfolds properly can't see why it shouldn't do that when deployed from the booster???
I have been practising gliding descents with my Easystar using just elevator and rudder input to simulate the v-tail mixing on the glider.

Awesome project, and great thread!