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Dec 07, 2018, 07:48 PM
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PARK-VTPR Aerobatics Intro


Life has its surprises, even in the hobbies we love... Hi, Iím new to the Electric Sailplane group and am about to embark on a flying style that is new for me with electric motor assist, and not really known in RC in general. I do come from a Slope modeling and flying background ranging from floaters to F3B and glider aerobatics since 1992. I have designed and flown many of my own creations, and I am the design owner of the GRYPHON aerobatic wing. You may have heard of it going all the way back to the 70ís when Ron Neal designed it.

This video will help you understand my next chapter of glider design and a newly conceived flying type I call ďPARK-VTPRĒ. You may have heard of Slope VTPR aerobatics but itís not been officially done as a proven style and type with no lift and a motor attached, in a park or on the beach, or for that matter anywhere on the plain. Itís similarly been called freestyle aerobatics, but as you follow along, you will notice a distinct difference from that versus VTPR which the French conceived over 30 years ago. I want to bring that to the park. So, this is my next step in RC glidering and I hope some of you will tag along and help us develop some new models, and the style. I will be presenting my latest 2.8m electric creation with build and design notes and images for you to view. And I am open for any suggestions in moving our RC hobby forward another step towards new fun. And FUN is what this is all about...

Thanks for your interest.

Eric,
VTPR Aerobatics

Introduction of PARK-VTPR Aerobatics
PARK-VTPR Intro (16 min 12 sec)
Last edited by oldscooler; Jan 27, 2019 at 02:47 PM.
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Dec 09, 2018, 09:32 AM
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TyFlies's Avatar
Very glad to hear that you're working on an electric VTPR project! I like to slope soar, but have to drive several hours to a do it since I live in the flatland.

I’ve been following your slope thread and have been kicking around the idea doing a VTPR build, but with a power system. I believe there are some designs in the 1.7 meter range, I’m leaning toward that size. And hopefully a design with some durability.
Dec 09, 2018, 09:39 AM
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TyFlies's Avatar
A VTPR slope video...
VTPR 2012- LEROYER Guillaume with Sonic (5 min 14 sec)
Dec 10, 2018, 12:24 AM
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Quote:
Originally Posted by TyFlies
Very glad to hear that you're working on an electric VTPR project! I like to slope soar, but have to drive several hours to a do it since I live in the flatland.

Iíve been following your slope thread and have been kicking around the idea doing a VTPR build, but with a power system. I believe there are some designs in the 1.7 meter range, Iím leaning toward that size. And hopefully a design with some durability.
Thanks for your interest and I would really like to see you do a 1.7. Great fun size and if you keep it light with an ejectable wing, will give you more confidence on the sticks when going low. If you need any help let me know.

The Leroyer video you posted is just so good, and William hadnít flown in over 2 years when his dad filmed it! 6 time French National Aerobatic Champion right there!

Here is the only video I know of that attempts to represent what we are presenting in the PARK-VTPR flying concept. Itís an electric Excalibur 2.5m on the beach. Itís not much but enough to get the PVTPR juices running lol. Hopefully it gives viewers a glimpse into whatís possible in the future of this new type of VTPR.

Eric

excalibur 2.0 vtpr on the beach (2 min 6 sec)
Last edited by oldscooler; Dec 11, 2018 at 02:57 AM.
Dec 12, 2018, 01:25 AM
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This video of Julian Benz and his Xplorer 3 in certain sections demonstrates the concept of low and slow PARK-VTPR flying with motor assist. With the design of a very light air frame and on-demand electric propulsion, one can only imagine the many low & slow possibilities. Granted it will be more dangerous because the slope pilot can no longer rely on upward slope lift as he is accustomed to. 3D Park flyers will easily catch on. The left stick now becomes the main input that determines just how low and slow one can safely execute and maintain a controllable aerobatic aloft state!

Eric

Xplorer 3 Acrobatic-Fligth Julian Benz (5 min 35 sec)
Dec 12, 2018, 12:38 PM
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TyFlies's Avatar
Any thoughts about a good model choice to add a power system to would be great.

Here's what I'm thinking:
-Sheeted foam wing. (Or possibly low density EPP, which I'd cover with 3mil laminating film.)
-1.5 meter to 2 meter wingspan
-As durable as possible. So the wing should probably either be connected with rubber bands or with nylon bolts going into a strong block.
-I do have EPP fuse material, but if EPP, I'm guessing the hollowed out nose area would need to be reinforced with carbon rods or strips.
-Since this plane will probably get a bit beaten up, I'd like to keep the build as simple as possible.
-I'd build it as light as possible

Do any 1.5M -2M models seem like a electric good option?

Found your link of some slope model options.
https://vtpraerobatics.blogspot.com/...st-part-7.html

Thanks!
Dec 12, 2018, 07:56 PM
vtpraerobatics.blogspot.c om
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Quote:
Originally Posted by TyFlies
Any thoughts about a good model choice to add a power system to would be great.

Here's what I'm thinking:
-Sheeted foam wing. (Or possibly low density EPP, which I'd cover with 3mil laminating film.)
-1.5 meter to 2 meter wingspan
-As durable as possible. So the wing should probably either be connected with rubber bands or with nylon bolts going into a strong block.
-I do have EPP fuse material, but if EPP, I'm guessing the hollowed out nose area would need to be reinforced with carbon rods or strips.
-Since this plane will probably get a bit beaten up, I'd like to keep the build as simple as possible.
-I'd build it as light as possible

Do any 1.5M -2M models seem like a electric good option?

Found your link of some slope model options.
https://vtpraerobatics.blogspot.com/...st-part-7.html

Thanks!
You bring up a really good point. On the slope, 2m span works great with lift and are a lot of fun with no worries. Here is my 72” scratch built Super-Jig VTPR model, all wood with veneer wings, 9.5oz wing loading (41oz). This is how we basically want to fly in the park….

Super Jiggin the Point (4 min 8 sec)


Moving to the flat-land though with NO lift, that’s another story. Suddenly you need more square inches on your wing design due to the fact that you are carrying lipo batt, motor and prop on the nose. The plane needs to be balanced with weighing the tail. Hence the wing loading goes up and you will have to fly faster to stay aloft.

This is the prime reason 2.5m or larger is preferred. They give you much more leeway and they are actually easier to fly whether the slope or the park. So, it really comes down to how fast or slow you want to fly, or come up with really light airframe as you already know. I would think if you can design a 2m ship having a 7-8oz wing loading RTF, you would have a nice predictable ship.

Airfoil? Our favorite foil on the slope is the SB96V/VS at 9.35% thick. But again, with no lift in the park it may be a bit fast. Take it to 12% or so and it will be much gentler and still have decent penetration I would think.

Not sure EPP is the way to go. Its durable and all, but it’s also heavy which means more speed. Again, you would need more square inches on that wing. 2.5 is the way to go IMO.

I know of no 2m model on the open market that would fit the bill. Again, PARK-VTPR has really never officially been established, hence why I have begun this thread. There will be trial and error which is in itself exciting. Eventually other aerobatic flyers will chime in here with some innovative ideas, I hope...

Eric
Last edited by oldscooler; Jan 27, 2019 at 05:39 PM.
Dec 12, 2018, 09:50 PM
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Paul Naton's Avatar
Why wait for wind, electric akro is great training for slope and high performance big air thermal flying. Been experimenting with power-assist sloping since the mid 90ís, nothing funner than a vintage 20 cell NiMh F5B on the slope in any lift!

Here are a few clips of me flying a 2 channel Radian, my Xplorer, and Egida with various power set ups on the flat lands. Great for keeping your thumbs sharp when the slopes are not working. Just donít let your glider evolve into those soul-less foamy 3-D planes the others fly.

Don't be a gliding purest if you don't have to.

Paul Naton
Radio Carbon Art Productions
R/C Soaring Training Videos
http://radiocarbonart.com/
http://glidefast.typepad.com/
https://www.youtube.com/user/pnaton
https://vimeo.com/radiocarbonart

Radian Acro Practice.mp4 (4 min 48 sec)
Dec 12, 2018, 09:50 PM
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Xplorer X3 F5J Freestyle Low & Fast Acro Flight (5 min 47 sec)
Dec 12, 2018, 09:51 PM
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Paul Naton's Avatar
F5J Egida Fall Aerobatic Glider Freestyle Flight (6 min 52 sec)
Dec 13, 2018, 12:03 AM
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Low and Slow


Thanks for your posts Paul. Glad you checked in. Really great flying. And yes, gliding purity takes the fun out of it. Now we want to see you taking them down within 2 wingspans and much more inverted with figures and such. We like at least 50% stick time inverted. You can do eet...

Here is a privately designed purpose built VTPR 2.5m ship called Flyer out of France. Fiberglass fuselage, veneer white foam wings. This is what we are aiming for in the flat-land. Now imagine an E version and flat land underneath it! Thats Park-Vtpr.

Eric

VTPR en Flyer light (5 min 59 sec)
Last edited by oldscooler; Jan 27, 2019 at 05:40 PM.
Dec 13, 2018, 01:33 AM
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TyFlies's Avatar
Thanks for posting the videos Paul.

Quote:
Originally Posted by oldscooler
This is the prime reason 2.5m or larger is preferred. They give you much more leeway and they are actually easier to fly whether the slope or the park. So, it really comes down to how fast or slow you want to fly, or come up with really light airframe as you already know. I would think if you can design a 2m ship having a 7-8oz wing loading RTF, you would have a nice predictable ship.

Airfoil? Our favorite foil on the slope is the SB96V/VS at 9.35% thick. But again, with no lift in the park it may be a bit fast. Take it to 12% or so and it will be much gentler and still have decent penetration I would think.

Not sure EPP is the way to go. Its durable and all, but itís also heavy which means more speed. Again, you would need more square inches on that wing. 2.5 is the way to go IMO.

I know of no 2m model on the open market that would fit the bill. Again, PARK-VTPR has really never officially been established, hence why I have begun this thread. There will be trial and error which is in itself exciting. Eventually other aerobatic flyers will chime in here with some innovative ideas, I hope...
Eric
Interesting thoughts about size and wing loading.
Today I was kicking around the idea of modifying LEGís LeFish kit to accept a light power system. But itís wing loading may not be floaty enough for flatland VTPR. (His kits do make great slopers though).
https://www.leadingedgegliders.com/p...fish-66-in-epp

For what itís worth, Iíve got a 2.4 meter NAN Orion crunchie, but it will be awhile before I do a low roll with it. But the next time I fly it Iíll definitely play around with it lower and slower.
Dec 13, 2018, 07:50 PM
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Quote:
Originally Posted by TyFlies
For what itís worth, Iíve got a 2.4 meter NAN Orion crunchie, but it will be awhile before I do a low roll with it. But the next time I fly it Iíll definitely play around with it lower and slower.
Your Orion appears would be around 8.5oz wing loading, maybe 8 depending on gear weight which is not too bad. I donít know anything about the airfoil but I would mix snap-flaps in and give her a whirl 40-50 feet off the deck and see how she does. Post some video too...
Dec 13, 2018, 08:51 PM
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Great idea. The Orion has a thermal airfoil, but it’s heavier and more solid than dedicated TD planes. Does great on the slope and it's sporty enough for high speed dives and flatland fun.

My current tx program is based on Sherman Knight’s sailplane programming, which is geared toward thermal. I do need to make some programming tweaks to bring out the fun factor a little more.

And when inverted, adding some reflex (speed mode on a switch) helps makes it floatier - if inverted.

Edit: Most Orions build out to a wing loading in the 10.5 - 12 oz / sq ft range depending on weight of power system and Lipo. No longer in production. There’s a good thread in this forum.
Last edited by TyFlies; Dec 16, 2018 at 07:23 PM.
Dec 15, 2018, 03:12 PM
Abundantly deficient.......
CptMike's Avatar
This is great! Being able to fly a glider in the VTPR style anywhere, close and personal, with electric assist is an amazing idea. Really don't need a very big area either as you're flying in a fairly small box. But having the right glider is of course another thing. Good to see your efforts here Eric and I'm with you on finding or creating a model that will do it in the true VTPR tradition on the field.

Here'a a small effort on my part to fly it on the field with a 2.7m glider. She has power but this short vid shows just gliding for almost a minute. Just need to brave-up and do it inverted......work to do, lol.

Odyssey 2.7 VTPR attempt 1 (0 min 59 sec)


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