Jet Glider
05-24-2005, 07:20 AM
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Jet Glider
Just had to share with you all this creation. we had an Airworld swift aerobatic glider but no tug to aerotow it. We then had the idea of mounting a turbine on the top and make it self launching. The turbine is an AMT Mercury (not an HP) but it has adequate power to launch the glder from grass. Now we can take off and fly aerobatics on the way up !!!
Next thing its to try aerotowing a power model behind the glider ??!
Will try anything once
John Greenfield
Ghost Squadron Model Aircraft Team
Next thing its to try aerotowing a power model behind the glider ??!
Will try anything once
John Greenfield
Ghost Squadron Model Aircraft Team
05-24-2005, 08:06 AM
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RE: Jet Glider
Swift on its own weight 35lbs and with the turbine installation it now comes out at 41lbs. The turbine provides very little drag and the glide performance seems unaffected. The glider aerobats even better now due to the additional weight providing more energy.
John
John
05-24-2005, 06:34 PM
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RE: Jet Glider
Hi jonjon,
Does the vertical stabilizer deform by the exaust heat?
I'wd like to know the thrust line with respect to the wing cord.
Good job!
Best regards,
Alex
Does the vertical stabilizer deform by the exaust heat?
I'wd like to know the thrust line with respect to the wing cord.
Good job!
Best regards,
Alex
05-24-2005, 06:52 PM
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RE: Jet Glider
JonJon,
I would like to see this thing take off from grass, please post a video clip if you can.
I have seen a large jet powered model glider fold it's wings when the pilot pulled too much G in a loop/turn.
It was in a Scandinavian country, lots of snow, fozen lake bed. WATCH OUT !
I would like to see this thing take off from grass, please post a video clip if you can.
I have seen a large jet powered model glider fold it's wings when the pilot pulled too much G in a loop/turn.
It was in a Scandinavian country, lots of snow, fozen lake bed. WATCH OUT !
05-25-2005, 03:31 AM
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RE: Jet Glider
Alex
No problem with heat distortion. I started off with a heatsheild on the front of the fin but took it off as it was not needed. you can put your hand on the front of the fin with the turbine at full power, its warm but nothing to worry about. The thrust line is set at 0 degrees relative to the root wing incidence and this seems about right. just a very slight climb at full power but this is probably more to do with the increased airspeed.
Spartan Missile
I have also seen the wing fold on the Norwegen model but did you see the amount of wing flex. My model is designed as an aerobatic glider. Its built by Airworld and I can assure you that it is strong. I have flown it for some time and seriously "tested" it...ever seen a glider do a 800ft diameter BUNT from the top....its one strong model....Thanks for your concerns though.
I do not have a video of the model...sorry maybe one day I will be able to post but my video camera is very old and not compatable with modern technology !!!
John
No problem with heat distortion. I started off with a heatsheild on the front of the fin but took it off as it was not needed. you can put your hand on the front of the fin with the turbine at full power, its warm but nothing to worry about. The thrust line is set at 0 degrees relative to the root wing incidence and this seems about right. just a very slight climb at full power but this is probably more to do with the increased airspeed.
Spartan Missile
I have also seen the wing fold on the Norwegen model but did you see the amount of wing flex. My model is designed as an aerobatic glider. Its built by Airworld and I can assure you that it is strong. I have flown it for some time and seriously "tested" it...ever seen a glider do a 800ft diameter BUNT from the top....its one strong model....Thanks for your concerns though.
I do not have a video of the model...sorry maybe one day I will be able to post but my video camera is very old and not compatable with modern technology !!!
John
05-25-2005, 09:50 AM
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RE: Jet Glider
Jonjon,
I'm so impressed by the 9m Ventus.
I also consider to mount a 54mm class turbine (about 5~6kg static thrust) to a 1:3.5 Discus or 1:3.75 ASW28.
I worry about the length of the runway & the drag cause by grass.
I'm a slope pilot not familiar with sailplane take of from runway either by it's own power or aerotow.
I also worry about the drag (air resistence, parasitic drag ect...) cause by the turbine.
Any comment on the above combination?
Best regards,
I'm so impressed by the 9m Ventus.
I also consider to mount a 54mm class turbine (about 5~6kg static thrust) to a 1:3.5 Discus or 1:3.75 ASW28.
I worry about the length of the runway & the drag cause by grass.
I'm a slope pilot not familiar with sailplane take of from runway either by it's own power or aerotow.
I also worry about the drag (air resistence, parasitic drag ect...) cause by the turbine.
Any comment on the above combination?
Best regards,
05-25-2005, 10:04 AM
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RE: Jet Glider
Alex
What weight and wingspan is your proposed glider and does it have a wheel fitted. If you let me know I can better advise if a 54mm class turbine will be ok.
If the model has a wheel then take off should not be a problem. You will need someone to hold the wingtip off the ground at the start of the take off run...just like the full size...but as soon as the model is moving control is easy. The take off run with my model which weighs 41lbs and has a 8.5 kg thrust motor is about 30 to 40 yards in light wind conditions but I can haul it off much earlier if I need to.
The cross sectional area of the turbine is very small and I can detect very little difference during the glide. The additional weight of the installation has actually made the areobatic performance better as the model has more momentum.
Happy flying
John
What weight and wingspan is your proposed glider and does it have a wheel fitted. If you let me know I can better advise if a 54mm class turbine will be ok.
If the model has a wheel then take off should not be a problem. You will need someone to hold the wingtip off the ground at the start of the take off run...just like the full size...but as soon as the model is moving control is easy. The take off run with my model which weighs 41lbs and has a 8.5 kg thrust motor is about 30 to 40 yards in light wind conditions but I can haul it off much earlier if I need to.
The cross sectional area of the turbine is very small and I can detect very little difference during the glide. The additional weight of the installation has actually made the areobatic performance better as the model has more momentum.
Happy flying
John
05-26-2005, 05:59 AM
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RE: Jet Glider
John,
The weight of ASW28 is about 5.5Kg with 4m wingspan.
The 4.25m Discus is about 6.5~7Kg.
Both of them do have retracble landing gears.
I think the most important thing is the adverse effect of heat impose on the vertical & horizontal stabilizers.
Since the length of the fuselage is about 1.75~1.8m.
Best regards,
The weight of ASW28 is about 5.5Kg with 4m wingspan.
The 4.25m Discus is about 6.5~7Kg.
Both of them do have retracble landing gears.
I think the most important thing is the adverse effect of heat impose on the vertical & horizontal stabilizers.
Since the length of the fuselage is about 1.75~1.8m.
Best regards,
05-26-2005, 06:37 AM
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RE: Jet Glider
Alex
At that weight and size a 54 size turbine will provied more than enough power. you may even be able to de-rate it a bit and save on fuel consumption....or climb very fast.
If you are worried about heat on the fin make up a simple heat shield. This can be done from lithoplate folded around the front of the fin. set it forward of the fin by 15 to 20mm and attach it to the sides on the fin with 3mm spacers to allow an air gap. I was concerned that fitting such a sheild would have an adverse affect on handling but it made no difference. You can see the heat shield in the posted pictures.
Regards
John
At that weight and size a 54 size turbine will provied more than enough power. you may even be able to de-rate it a bit and save on fuel consumption....or climb very fast.
If you are worried about heat on the fin make up a simple heat shield. This can be done from lithoplate folded around the front of the fin. set it forward of the fin by 15 to 20mm and attach it to the sides on the fin with 3mm spacers to allow an air gap. I was concerned that fitting such a sheild would have an adverse affect on handling but it made no difference. You can see the heat shield in the posted pictures.
Regards
John
05-26-2005, 04:18 PM
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RE: Jet Glider
Hi all Jet-Glider freaks!
Have a look at this..
It`s from the onboard camera on my lost Ventus.
Finally it`s ready in JPEG format.
I strongly recommend the DVD from Fagernes Airshow this year!
You can get it from this adress: http://www.vfkm.no/dvd
Here it is, app 16 Mb.
http://www.workflow.as/jogrini/video/ventus_onboard.wmv
Congratulations with your Swift, it sure looks good!
Regards
Gudmund
Have a look at this..
It`s from the onboard camera on my lost Ventus.
Finally it`s ready in JPEG format.
I strongly recommend the DVD from Fagernes Airshow this year!
You can get it from this adress: http://www.vfkm.no/dvd
Here it is, app 16 Mb.
http://www.workflow.as/jogrini/video/ventus_onboard.wmv
Congratulations with your Swift, it sure looks good!
Regards
Gudmund
