1. What does VTPR mean?
The acronym translated from its French origin means “voltige très près du relief” or aerobatics very close to the terrain. The term was introduced to the US in 2005 by Pierre’ Rondel. How close is close? Within a few feet to inches of the ground sometimes touching.
2. What type of model gliders are preferred for VTPR?
Generally speaking a model glider with a wingspan of at least 1.5m up to 4m monoplane design. They can be constructed of fiberglass fuselages and or EPP foam components. Traditional balsa skin over a white foam core material can be utilized for the wings. The preferred airfoils to date are the SB96V/VS and TP42 symmetrical airfoils. VTPR models by design have larger than normal flight surfaces for extra control at slow air speeds. Some of notable mention are Sonic, Excalibur, Air-100, Le Fish, Zeppelin, Limande, Stiction, The Flo, Vol-Lent, Twister and Voltig. Anything that is aerobatic by design and lightweight can fly VTPR. The only limiting factor is the pilot.
3. What is the weight of VTPR gliders?
VTPR models are generally lighter (AUW – all up weight) than traditional ‘Totale’ slope aerobatic models we see covering large volumns of sky. A typical 60-72” model can have an AUW of 20-40ounces. The larger 2 to 2.5m models of composite construction vary from 45-60 ounces. Wing loadings usually run from 5-10 ounces per square foot of wing area. The low weight means a low mass inertia component that greatly helps a VTPR glider survive the rigors of the flying style.
4. How many servos are needed in a VTPR model?
Typically only four. Rudder, Elevator, 2 only ailerons. Flap servos are not needed as a VTPR model doesn’t develop great speed and are lightweight making them very maneuverable at low air speeds, therefore making them easy to land. The 4 servo unit helps keep the weight down and roll inertia low, thus a quick roll rate
5. What type of slope is preferred for VTPR flying?
For the best VTPR, a rounded and shallow slope with laminar air flowing across the top. The reason it is preferred to fly this type of slope with a good headwind is to be able to perform all manner of VTPR without limitation. What we mean by all manner is everything you can think or dream up you could possibly do with a glider very close to the ground. The headwind flowing over this shallow slope allows the current to remain consistently more horizontal to the ground angle as to actually allow the model to hover in place in a hands-off fashion if desired. This balance of nature and model is one of the sweet spots of VTPR.
6. What are some of the maneuvers (figures) normally flown in VTPR?
One of the marquis maneuvers is a low to the deck inverted path while touching the vertical fin to the terrain or vegetation while maintaining momentum. Another is half-snap rolls off the deck with only inches between wing tip and the terrain as the plane rotates. Wing tip touches upright and inverted, And of course, all other standard aerobatic maneuvers such as single and double rolls and 2 and 4 point rolls, all within a few feet of the deck! Knife-edge passes up to 3-5 seconds long are very impressive as it wasn’t but a few years ago it was thought a model glider couldn’t perform a KE. Catching the model is standard procedure in VTPR.
7. Someone said VTPR is only flown at slow speeds. Is this true?
This is not true. VTPR pertains to the relationship of the model as to its approximate height above the terrain. This is the zone where VTPR maneuvers are measured. Low or high speed has no significance except in developing the proper kinetic energy to complete a VTPR (height oriented) maneuver successfully. If one chooses to perform at low speed he must consider the model design and its built in durability to survive a hard hit. VTPR is very dangerous to a models survival. In this mode one of the secrets to flying VTPR slow is to understand it is performed without inertia and extreme agility. On the contrary if one wishes to fly a high speed, very low to the terrain maneuver, this too is VTPR. It’s just faster and even more dangerous to the model. Air speed is a preference that is wide open and directly relates to the model design and pilot comfort level. The sweet spot of true VTPR is “lowness to the ground”.
8. Is VTPR and Ultrabatics the same?
No, there is a distinct difference. VTPR has been around for at least 25 years in the traditional French style out of Brittany France. The new flip-flop low to the ground style of flying now seen with ultra-light EPP foam models is coined Ultrabatics. This style began in Southern California and Santa Barbara in 2011. Traditional VTPR consists of longer, flowing maneuvers that are called ‘figures’ and can cover larger areas. Ultrabatics is performed more in the pilots close proximity to the glider, even in his face in a manner that appears defying gravity with many quick and repetitive maneuvers such as “floops, flips and flops’. These ‘mad flips’ where the glider pitches in a forward or reverse tumble action utilizing a 180 degree moving mad elevator are very popular in Ultrabatics. VTPR tends to rely on less than Ultrabatic flight surface movements but more than standard slope model movements. VTPR can be flown much faster than Ultrabatics style due to the AUW (all up weight) and stiffer consruction of the model. A flexible Ultrabatics glider can easily fly in ‘hover mode a few feet off the deck and make impact with little to no damage. To hover a VTPR styled glider one would need more head wind to be successful. All in all, whether VTPR or Ultrabatics, both fill a great need to experience extreme and dangerous adrenalin pumping slope aerobatics. The trade off between both styles is all matter of pilot preference. Fly both, It’s all fun!
9. Are there any VTPR aerobatics contests for the competitor minded?
Not very many because the VTPR pilot population has very low numbers as compared to general slope aerobatic flyers. The first annual US VTPR Recontre occurred the summer of 2011 at Temple Hill slope, California. The second annual event occurred in the summer of 2012 at Glider Point Ca. A new VTPR format has just been introduced that simplifies and makes for a points competition that is fair and equal for all participants. This format is called ‘Slope Instant Scoring VTPR Contest’. It can be seen here. Secondly, there is in the works a contest called The V-CUP CHALLENGE event, the first of which will be flown in Southern California, USA. This is a semi-annual perpetual trophy challenge. Some VTPR contests occur in Brittany France, the motherland of VTPR where they occasionally have point’s contests. VTPR has been a part of the American slope scene maybe 5 years. It is hoped through education and exposure more new enthusiasts compete in VTPR contests.
10. How does one get started flying VTPR?
First, there is a good reason why VTPR pilots are few and far between. It’s not normal to fly a glider next to the ground or for that matter, any type of RC airplane. The new pilot needs to want to experience flying a model up close and personal as opposed to far away in traditional style. He needs to desire and crave the ultimate adrenalin rush of bringing his glider right to the ground in front of him enjoying mass amounts of fun. Then he needs to enjoy building and repairing his models because they will get broken. Foam EPP gliders fare well but even those will break up, just differently than a composite model. Seek out those that are already building and flying VTPR. A good place to start is at Slope VTPR Aerobatics website and this blog. These websites are 100% dedicated to VTPR.